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Wikipedia related words
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米 国Federal Communications Commission(FCC) defines broadband as downlink 2021Mbps / uplink 11Mbps from November 100... on the other hand,According to the (GAO) interview, even a small business needs a minimum of 100 Mbps downlink / 25 Mbps uplink.In addition,Electronic Frontier FoundationHas issued an opinion that the speed should be increased to about 100 Mbps for both uplink and downlink..
In Japan, uplink / downlink 30Mbps is defined as ultra-high-speed broadband (#Definition of speedreference).
Broadband antonymNarrow bandAnd the narrow band has a low capacityDial-up connection,ISDN,PHSMeans such as.Low capacityADSLEtc. are also called narrow bands.Between broadband and narrowband is called
the 1980sHigh-speed lines have high line charges and connection charges (512 yen or more per month), communication speed of 1.5 kbps to 6 Mbps, XNUMX Mbps to tens of Mbps in special casesDigital line(Optical fiber),large company,computersRelationCompany, Even more advancedUniversity-ResearchIt was used by the institution.
the 1990s, ExistingTwisted pair cableCommunication lineUsing,soundHigh, not a voice signalfrequencyAnd communicate with high-band electric signalsDSLAndCable TV Ofcoaxial cableCommunication service usingDOCSIS) Was developed.
the 2000sThe optical fiber can be directly or indirectly led to the user's home.FTTH-FTTAlso started laying.Broadcast on optical fiberOptical broadcastingAppeared and competed with cable TV, and cable TV graduallyFTTHConvert toTelecommunications carrierとCATV operatorThe difference was filled.
the 2010sIntroduced a 10Gbps service for home use by FTTH.Also, slow ISDN and ADSL have been announced to be terminated due to maintenance cost issues.,Digital cable TVAlso the coaxial cable equipment is aging[Note 1]Goes onInstead, optical lines became widespread.
the 2020sThe optical line is scheduled to be a universal service.
Broadband originally meant a wide frequency band.For example, even before the generalization of home-use data communication, cable TV companies were able to provide services beyond cable TV broadcasting by using a broadband communication system (broadband communication system).
Then in the 1980sEthernet2.0 is here,coaxial cableHas come to be used for data communication as well, but with a narrow band baseband coaxial cable, only half-duplex communication of up to 50 Mbps was possible.On the other hand, wideband broadband coaxial cables enabled full-duplex communication of up to several hundred Mbps..
In 1988, wideband and high speed centered on optical fiber (B-ISDN) specification ITU-T Rec. I.121 is now available,TraditionalTwisted pair cableThe central narrowband, slow ISDN became known as the narrowband ISDN (N-ISDN)...In this I.121, broadband ISDN is defined not by the width of the frequency band but by the speed of transmission speed.After that, the line with high communication speed was called broadband, and the line with low communication speed was called narrow band.
Later, it is said that US cable TV companies began to use the term broadband for Internet connections..
Definition of speed
The speed called broadband is increasing year by year.In early Internet connections, speeds below broadband ISDN (156Mbps or 622Mbps) as well as narrowband ISDN (1.544Mbps or 2.048Mbps)) It was also called broadband at the following speeds.
For example, the United States in 1999Federal Communications Commission In the (FCC) report FCC 99-5Dial-up connectionBroadband was defined as "downlink 200kbps or higher" that exceeds the speed ofHowever, the report also stated that in the future, technological evolution would "we would consider today's broadband to be a narrow band."..Since then, the definition of broadband has been accelerated in the United States as declared:
|FCC broadband definition||After February 1999||After February 2010||After February 2015||After February 2021|
|Actual descent speed||200kbps or more||4Mbps or more||25Mpbs or more||100Mbps or more|
|Actual ascending speed||200kbps or more||1Mbps or more||3Mbps or more||20Mbps or more|
On the other hand, in Japan, it is said that "512kbps or more" has come to be called broadband in the private sector.But in 2001e-JapanIn the strategy, the term broadband is not used, and the one suitable for music download is "high-speed Internet access network" (speed not specified), and the one suitable for large-capacity video download is "ultra-high-speed Internet access network" (30Mbps-100Mbps standard). Stipulated..The "ultra-high-speed Internet access network" in the e-Japan strategy at that time was premised on optical fiber, etc.However, a few years later, ADSL and CATV Internet have reached a nominal speed of 30 Mbps or more due to the increase in speed.
After that, in the "Next Generation Broadband Strategy 2006" in 2010, 30Mbps or more for both uplink and downlink was defined as "ultra-high-speed broadband"., In 2010, "Path of Light", ultra-high-speed broadband became simply called "broadband".However, even at that time, the definition of speed remained at the nominal speed.
When the corona disaster spread and telework and distance education became widespread in 2020, the quality standard of broadband became a problem at the "Study Group on the Ideal Broadband Infrastructure" to consider the universal service of broadband...However, as of February 2022, 2, the draft quality standard for wired broadband continues to indicate the conventional "upstream / downlink nominal speed of 2 Mbps or higher" as a provisional form..
Major broadband formats
There are two types of broadband access line provision services, one that uses its own network and one that rents another company's network.There are also services that use both the company's own network and the networks of other companies.The main optical access line provision services using the company's optical fiber network are as follows:
- Communication system (NTT's FLET'S Hikari, KDDI'sau HikariSuch)
- Electric power system (Tokyo Electric Power CompanyTEPCO Hikari(Migrate to au Hikari[Note 2]), Kansai Electric Power's eo Hikari, Chubu Electric Power's Commufa Hikari (sold to KDDI), Kyushu Electric Power's BBIQ, Okinawa Electric Power'sHikarifuru(End) etc.)
- CATV system (J: COMsystem,TOKAIsystem,CCJsystem,CNCISystem etc.)
- Railway system (TokyuSystemIt's Com,KintetsuSystemKCN,Hanshin Electric RailwaySystemBaycomSuch)
The regions and maximum speeds of major optical access line providers are as follows (maximum speeds are only part of the region):
|NTT system(FLET'S Hikari）||1Gbps[s1]||10Gbps[s2]||1Gbps[s1]||10Gbps[s2]||1Gbps[s1]||10Gbps[s2]||1Gbps[s1]|
|KDDIsystem (au Hikari-Commufalight)||1Gbps[s3]||10Gbps[s4]||1Gbps[s3]||10Gbps[s5]||1Gbps[s3]||No||1Gbps[s3]||1Gbps[s6]|
|Sony system(NURO light）||10Gbps||No||10Gbps||No||10Gbps||No||10Gbps||2Gbps (Hiroshima / Okayama)||No||10Gbps (Fukuoka / Saga) ||No|
|Optage(eo light）||No||No||No||No||No||10Gbps (Fukui)||10Gbps||No||No||No||No|
|JCOM (J: COM NET Hikari)||1Gbps||1Gbps (Sendai)||10Gbps||No||No||No||10Gbps||1Gbps (Shimonoseki)||No||1Gbps||No|
|TOKAIsystem[s7]||No||10Gbps (Sendai)[s8]||10Gbps (Kanagawa)[s9]||1Gbps (Nagano)[s10]||10Gbps (Shizuoka)[s11]||No||No||10Gbps (Okayama)[s12]||No||No||No|
|CCJsystem (NCT light-CTY light-CNS light-JCV Hikari)||No||No||No||10Gbps (Niigata)[s13]||10Gbps (Mie)[s14]||No||No||No||No||No||No|
|ZTV (ZTV Hikari)||No||No||No||No||1Gbps (Mie)||No||10Gbps (Kyotanba Town)|
|Azumino TV||No||No||No||10Gbps (Nagano)||No||No||No||No||No||No||No|
|San'in Cable Vision||No||No||No||No||No||No||No||10Gbps (Shimane)[s15]||No||No||No|
|Okinawa Cable Network||No||No||No||No||No||No||No||No||No||No||2Gbps[s16]|
|Tokyusystem[s17] (Shinagawa Hikari-It's com Hikari)||No||No||10Gbps (Shinagawa)|
2Gbps (Tokyo / Kanagawa)
|Kintetsusystem[s18] (K Broad Hikari)||No||No||No||No||No||No||10Gbps[s19]||No||No||No||No|
|Hanshin Electric Railwaysystem (Baycom light)||No||No||No||No||No||No||1Gbps (Hyogo / Osaka)||No||No||No||No|
- ^ a b c d FLET'S Hikari Giga Family / Giga Mansion
- ^ a b c FLET'S Hikari Cross
- ^ a b c d au Hikari Home 1 Giga / Mansion Giga
- ^ au Hikari 10G
- ^ Chubu Telecommunications"Commufa Hikari 10 Giga Home"
- ^ Okinawa Cellular Phone"Au Hikari Chura Home" "au Hikari Chura Mansion Giga"
- ^ Not only "TOKAI Cable Network" but also "TOKAI Cable Network"Sendai CATV""Atsugi Isehara Cable Network""L sea buoy""Toko Channel Shizuoka”And so on.
- ^ Sendai CATV"Cat Vi Hikari 10 Giga"
- ^ Atsugi Isehara Cable Network"Ayu Net Hikari 10G"
- ^ L sea buoy"Hikari de Net 1G Course"
- ^ TOKAI cable networkas well as the Toko Channel Shizuoka"Hikari de Net 10G"
- ^ Kurashiki Cable TV"Hikari 10G Service" (planned)
- ^ N.C.T."NCT Hikari 10G" (Joetsu Cable Vision"JCV Hikari" is up to 1Gbps)
- ^ Cty W"CTY Hikari 10G Course" andCable net suzuka"CNS Hikari 10G Course"
- ^ Marble Net 10G Course
- ^ Hikari Nirai
- ^ "Cable TV Shinagawa""It's Communications""Izukyu Cable Network"including.
- ^ "Kintetsu Cable Network"(KCN) as well as the affiliated"KCN Kyoto""Komadori cable""TV KishiwadaIncluding.
- ^ Komadori cableArea is up to 1 Gbps
Wireless broadband lineMobile communication network/Mobile Wireless Access It is popular mainly in (MWA).For this4G(LTE-Advanced-WiMAX 2.1) And5G(Including WiMAX 3 and XGP 4.0) exists.Mobile broadband linesMobile broadbandIt is called (Mobile broadband).For the main providers of mobile broadband in JapanNTT DoCoMoとKDDI (au) andSoftbankとRakutenThere is.
|MWA service||Standard maximum value||NTT DoCoMo||au||Softbank||Rakuten Mobile|
|4G maximum reception speed||3Gbps||1.7Gbps||1Gbps||838Mbps||?|
|4G maximum transmission speed||1.5Gbps||131.3Mbps||112.5Mbps||46Mbps||?|
|5G maximum reception speed||20Gbps||4.9Gbps (5G SA)||4.2Gbps||3.0Gbps|
3.7Gbps (5G SA)[w1]
|5G maximum transmission speed||10Gbps||1.1Gbps (5G SA)||481Mbps||298Mbps|
444Mbps (5G SA)[w1]
Mobile communication networks have limited capacity, so the public無線 LANData offload to..Also, on iOS 11 or laterIt is also possible to automatically send data that cannot be handled via (public) wireless LAN to the mobile communication network due to the function.[Note 3]..In the public wireless LAN service of the mobile companySIM cardMany of them support the EAP-SIM authentication method using.
|Public Wi-Fi service||Standard maximum value[w2]||d Wi-Fi (NTT DoCoMo)||au Wi-Fi SPOT[w3] (ouch)||Softbank Wi-Fi spot[w4]|
|11n maximum communication speed||600Mbps[w5]||72.2Mbps or more||150Mbps or more||Maximum speed unknown|
|11ac maximum communication speed||6.9Gbps[w6]||?||433Mbps or more||Maximum speed unknown|
|11ax maximum communication speed||9.6Gbps[w7]||?||?||Maximum speed unknown|
- ^ a b As of August 2022, only Kamiochiai 8-chome, Chuo-ku, Saitama City, Saitama Prefecture
- ^ It is the maximum value in one connection, and the total capacity of the dual band / triband / quadband Wi-Fi master unit can exceed this (Archer AX1 etc.).
- ^ Wire and wirelessとUQ CommunicationsUses Wi-Fi network
- ^ oldBB mobile pointAlso exists.
- ^ In the case of 40Mhz 64QAM 4x4MIMO (half for a 2x2MIMO smartphone)
- ^ In the case of 160Mhz 256QAM 8x8 MIMO (2/2 on a 4x1 MIMO smartphone)
- ^ In the case of 160Mhz 1024QAM 8x8 MIMO (2/2 on a 4x1 MIMO smartphone)
We also used wireless for broadband for fixed linesFixed wireless access(FWA) exists.This involves installing a fixed antenna outside the house or near a window to send and receive to and from the base station. There are short-distance and long-distance FWA.The consumer standard developed for long-distance fixed wireless access has a width of 4.9Mhz in the 20Ghz band.High output wireless LANIEEE 802.11j has a maximum communication speed of 54 Mbps and is for fixed use of the same band and width.WiMAXHas a low maximum communication speed of 74.8 Mbps, and for high-speed access lines, it is mainly IEEE 4.9j / n in the 802.11 GHz band (100 Mbps or higher).), 18GHz band, quasi-millimeter wave band, millimeter wave band, etc.Fixed micro lineIs used.By using a repeater, wireless transmission over a longer distance is possible, and it is mainly used as a backup access line or relay line when the optical fiber is cut due to a disaster (wired laying on remote islands is extremely difficult. It may still be used as the main line in some areas).
Offshoreaircraft"High-throughput satellite" (HTS; high-speed and large-capacity) for broadband for ships in the open seaCommunication satellite)bySatellite internet accessIs used.For thisIntelsat"GX Aviation" "Fleet Xpress","Exede In the Air",Space xof"Starlink"SKY Perfect JSAT"JSAT Marine" etc. exist.In addition, communication satellites are also the last line of recourse for international communication when international lines such as submarine cables are cut off due to accidents, disasters, incidents, etc., especially only one submarine cable is connected.トンガThere are more opportunities to play an active part in an island country like.. HoweverSpaceHigh-speed satellite communication that transmits and receives to and from requires a parabolic antenna, which is difficult to miniaturize, so its use is limited.AtmosphereCan be placed in and sent and received with a smaller antennaStratosphere platform (HAPS) is also being considered.
In addition, wireless broadband has a slower uplink speed than optical fiber connection, and its stability is lower depending on atmospheric conditions and building conditions.Telemedicine,Telework,Distance learningWill be disadvantageous to..It is also said to be vulnerable to congestion..
In order to improve the connection stability in the building, draw a wired line to the inside of the house and close it to the terminal無線 LAN Ofaccess point(Wi-Fi spot) AndLTE OfFemtocellNeed to be installed.Also spread the radio waves with linesLeaky coaxial cable There is also (LCX), which is used indoors and in tunnels..
Expanding the use of broadband
Broadband Internet connection is provided on a flat-rate basis from the beginning and can be used without being aware of communication charges and time zones, which has brought about a major change in the Internet usage pattern with its widespread use (although, likewise).FLET'S・ Narrowband flat-rate services such as ISDN were also provided in advance).
Always connectedI made the most of thatIP phone-Internet phone, Because it became possible to send and receive large amounts of data in a short timeCloud computing-Via internet connectionstorageAccess to (offsite data storage), broadbandVideo on demand-IP broadcastNew services such as video broadcasting such as (IP TV) have become possible.
Web pages are already centered on rich content on the premise of broadband. For example, as of August 2022, 8, the median value (1% tile value) for desktop sites is about 50MB, and the 2.3% tile value is about 75MB. 4.6MB, 90% tile value is about 8.9MB.On the other hand, web pages load more than 2 seconds and it feels tedious., It is said that the bounce rate increases when it exceeds 3 seconds, Simple calculations are not possible due to delay loading and rendering time, but a sufficiently fast communication line is required for comfortable viewing.
Call (IP phone, IP videophone, video conference)
Calls using IP communication (VoIP-IP phone) Is low quality in the era of ADSL and low speed FTTHSecondary phoneHas appeared.In the early days of VoIP, only calls were made between IP terminals, but since the phone number 2002 was assigned to an IP phone in November 11 (050 IP phone), it is possible to make and receive calls with general subscriber phones even with VoIP. Became.
After that, high quality using broadbandPrimary phoneWith the advent of IP phones, the use of telephone numbers with the same area code as general subscriber phones was approved, and IP phones became widespread ().Hikari phoneSuch).Since primary telephones have network quality regulations, they are mainly paid services that use the priority communication function within the closed IP network (non-Internet).
It has been a long time ago to connect IP phones to general subscriber phones and IP phones of other companies.Public switched telephone network (PSTN) has been used, but from January 2021, IP telephone operators will exchange telephones with each other as IP.From 2024 to 2025, it is planned to switch to IP network telephone exchange for general subscriber telephones.However, the charges remain pay-as-you-go.
On the other hand, using the non-priority communication InternetInternet phone(Voice communication / voice chat)SkypelikeP2P communicationFree calling services have become popular, and "" that keeps them connected has become common due to the constant connection of broadband.
Broadband has also generalized not only one-to-one but also many-to-many calls (group calls, conference calls). Even on SNS, "ClubhouseVoice SNS such as "" has appeared, and short-text SNS "TwitterBut the voice conversation function "SpacesHas appeared.
Videophone / video conference
Also on the internet phone mentioned aboveSkypeMany of them are compatible with videophones.
According to NTT Group's announcement, the fatigue of online meetings isSound qualitysaid to be influenced byBut sound quality depends not only on physical microphones and earphones, but also on compression codecs.The sound quality standards for compression codecs includemean opinion score (MOS), etc., but basically a codec with a high compression rate has a low sound quality, so a wider and stable line band is required for high sound quality.
Broadcasting (optical broadcasting, IP broadcasting, simultaneous TV distribution)
Broadcasting by broadband is also performed, but the capacity of broadcast data on normal broadcast waves is enormous as follows:
|Broadcast type||Digital terrestrial broadcasting||BS digital broadcasting||110 degree CS digital broadcasting||Cable television broadcasting|
|Number of physical channels||40||23[Note 4]||26[Note 5]||51[Note 6]|
|Per physical channel|
Maximum bit rate
|Approximately 16.8Mbps (Full Seg) + |
About 312kbps (One Seg）
|About 100Mbps[Note 7]||About 38Mbps[Note 8]|
Therefore, re-transmission via the Internet is inefficient, and re-transmission by another method is the main method.However, the cost of terrestrial digital broadcasting transmission equipment is rising.Since 2021, the Ministry of Internal Affairs and Communications has been considering a broadband alternative to difficult-to-view broadcasts..
Optical broadcasting and internet retransmission
Communication optical fiber (in optical line)Optical communication) And broadcasting optical fiber (Optical broadcasting) And multiplexing (Optical WDM communication) Is being integrated.In addition, a service provided by two cores, one for optical communication and the other for optical broadcasting, without multiplexing (eo optical TV).Etc.) also exists.
In the optical broadcasting method, a broadcasting wave modulation method in which a broadcasting wave is modulated and mounted on an optical fiber (SKY PerfecTV! Premium Service Hikari(FLET'S TV), etc.) and IP multicast method (IP multicast method) that sends broadcast data from a closed network by IP transmission of optical lines.Hikari TVEtc.) is the mainstream.
In the broadcast wave modulation method (RF optical transmission), normal broadcast wave pass-through is performed.Specifically, after converting the broadcast wave into an optical signal, it is distributed by an optical splitter and used in each house.Optical line terminatorIt is in the form of returning to the electric signal on the coaxial cable, and after returning to the electric signal, it can be viewed using a general TV tuner.For broadcast wave modulation, in addition to pass-through signals, it is for set-top boxes for traditional cable television broadcasting (CATV).Transmodulation signalIs also being multiplexed..Since the optical fiber has a very wide band, it is possible to always provide all the broadcast signals shown in the above table at the same time without affecting the data communication in the broadcast wave modulation.
In the IP multicast method, priority communication in a closed IP network is generally used, andIPv6Of the protocolMulticast listener search (MLD) allows the required broadcast data to be sent only to the required recipients...In the part of the passive optical network (PON) branched by the optical splitter, the multicast LLID can be used to allow multiple subscribers' optical network units (ONUs) to receive single data at the same time...A general TV tuner cannot be used for viewing, and it is dedicated.Set top boxEtc. need to be used. In the IP multicast method, the bandwidth is compressed by priority communication, so the video is recompressed, and the communication speed required for viewing it is, for example, 1 Mbps per channel for HD broadcasting on "Hikari TV"., 4 Mbps per channel in 1K broadcasting..There is also a set-top box equipped with a triple tuner, and the communication capacity several times that is used per set-top box..
Some broadcast receivers that can be used for these methods are for home networks.DLNAWith connection methodDTCP-The combination of IP communication enables home IP retransmission of broadcasting.With the advent of DCTP + (DTCP-IP 1.4), it has become possible to retransmit broadcasts via the Internet.
For mobile terminals, 5G Broadcast is a universal broadcasting standard for mobile terminals that uses radio waves.[Note 9]However, 5G broadcasting is still in the examination stage overseas and has not been widely used.Also, in Japan's own standard, ISDB-TOne SegBroadcasting was widespread, but it is not compatible with XNUMXSegiPhoneWith the advent of XNUMXSeg, the reception rate of XNUMXSeg has decreased..
Therefore, simultaneous distribution via the Internet has become important for public broadcasting..
Simultaneous delivery on the Internet
Non-priority communication and one-to-one communication (Unicast) Is also appearing as an IP unicast simultaneous distribution service via the Internet.Many of these methods can be viewed with a general Web browser (dedicated).App or Application or Sakurabook AppThere is also).
In 2007, the P2P-based broadcast reception software "PXNUMXP-based broadcast reception software" was researched and developed with the support of the Ministry of Internal Affairs and Communications.Key Hole TVWas broadcasting TV broadcasts at the same time...After that, in 2010, the simultaneous radio broadcasting service "radikoIn the 2020s, a simultaneous distribution service for television broadcasting also appeared.
In 2020, NHK will release a TV simultaneous distribution service with SD image quality (1.5 Mbps).NHK PlusBegins in all days, It was made 2022 hours in April 4. Also,Private broadcastingAlso from April 2022 "TVerIs scheduled to be broadcast simultaneously on TV..
Video on demand
#Actual communication speedSee below.
OS and applications
For general information equipment, the OS (OS), which is the basic software for operating the equipmentoperating system) Is installed, and in addition, application software suitable for various purposes (Application software) Has also been introduced, but as the software becomes more sophisticated, the capacity of downloads and updates is increasing.
Android TVTV andBD recorderIn, it is possible to update the firmware by "broadcast download" using the broadcast wave of terrestrial digital broadcasting and BS digital broadcasting (engineering serviceHowever, other information devices basically require software updates via the Internet.
Most of the common software is for distributionContent delivery network(CDN, content delivery network) is adopted, and although high-speed and efficient download is possible even with large-capacity software, the capacity of the OS is large even with CDN, and the download can be done to general networks. Influencing..As a result, access line services that have been sped up by separating OS updates have also appeared (OCN light"IPoE Advance"Such).
Generally, game lines have lower latency than speed (LatencyLow) and stability (It is important that it does not occur.Some home routers have a QoS feature that prioritizes gaming packetsHowever, the effect does not extend to the access line[Note 10], On a narrow bandwidth shared access lineQueue(queue) Causes delay and packet loss due to timeout.Therefore, broadband is also important for low latency and stability.
In addition, speed itself is becoming more important year by year in game applications.Enriching the gameDownload contents While the increase in (DLC) has increased the capacity per game to over 1GB,storageIn, the loading time is shortened by speeding up rather than increasing the capacity (PlayStation 5,Xbox Series X / S, Windows PC DirectStorage API, etc.), the opportunity to download is increasing when replacing games.
Online storage, online backup
Actual communication speed
Bandwidth is not guaranteed for consumer broadband linesbest effort(Best effort), and there are various bottlenecks because the line is shared on the way... As of 2021, around 30% of users are experiencing problems with the effective speed of the Internet., The problem of effective speed affects not only video distribution but also web conferencing.
The FCC defines 100 Mbps downlink as broadband, and Japan defines 30 Mbps downlink as ultra-high-speed broadband, but the recommended communication speeds for actually watching 4K video with on-demand video distribution are as follows:
|On-demand video distribution service||YouTube||Netflix||Hulu||U-NEXT|
|Recommended connection speed for 4K video (Mbps)||20||25||16||15|
Therefore, if two or more people in the same household each watch 4K video, 30 Mbps will be insufficient (the average number of Japanese households as of 2020 is 2.27).). Alsooptical disk OfUltra HD Blu-rayIn, video of 82 Mbps or more is possible, and the bit rate lower than that is the mainstream for online distribution videos as of 2022.
In addition, the communication speed required for live video distribution with 4K resolution is as follows:
|Live video distribution service||YouTube Live||AWS Elemental Media Live|
|Recommended Bitrate for 4K 30fps Video (Mbps)||13~34|
|Recommended Bitrate for 4K 60fps Video (Mbps)||20~51||25 and over|
Live video distribution has a higher frame rate than general movies (24fps), it is difficult to perform advanced compression using a high amount of processing due to the need for real-time encoding, and the bit rate is redistributed for the entire video. Since (multipath encoding) is also impossible, the required bit rate tends to increase.
Optical communication speed
Number of access line branches,Provider (ISP) Network termination device (in the case of PPPoE) that is the boundary withVirtual fixed communication provider The boundary with (VNE)Network / network interfaceLine capacity (for NNI; IPoE), in ISP or in VNErouterProcessing capacity and line capacity,backboneThe line capacity ofInternet exchangeExchange ability etc.bottleneckTherefore, even if the maximum communication speed is advertised, the actual communication speed will be low.
In the consumer FTTH service, the line bandwidth is shared among subscribers, for example, NTT's "FLET'S HikariIn the access line, a maximum of 1 branches (about 32 Mbps per branch) including spares for a 1 Gbps contract and a maximum of 30 branches (about 10 Mbps per branch) including spares for a 64 Gbps contract are used. 1Mbps), and the bandwidth will be shared between subscribers (shared access method)...The average number of branches was 2016 branches in NTT East and 11.8 branches in NTT West at the end of 7.0, but it has deteriorated to 2020 branches in NTT East and 14.4 branches in NTT West at the end of 7.9..
Of the optical access line that sandwiches this optical splitterPassive optical networkIn (PON) multiplexing, there is also a mechanism called WDM-PON (Wavelength Division Multiplexing PON) that does not share a band, but according to a 2010 Atlantic Engineering Group estimate, WDM-PON is the current time division multiplexing. It is said that it costs about twice as much per contract as GPON of conversion (TDM)...Therefore, TWDM-PON (TDM M-PON, which is a combination of TDM and WDM (Etc.) have been formulated, but as of 2022, they are not yet widespread. As of 2021, NTT has an all-photonics network (APN) concept, and plans to stop time division multiplexing and introduce one wavelength per person in the future..
In the FTTH service for business use, a single star (directly connected to the core wire) method that is directly connected without sharing an access line (without using an external optical splitter) is also used...Previously, even for home use, the early "B FLET'S New Family Type" adopted the single star method...As of 2019, the useful life of optical fiber is 20 years for fictitious sections, 28 years for underground sections, and 21 years for submarine sections.However, according to an interview with NTT East as of 2005, 7% of optical fiber disconnections occur in the closure that houses the external optical splitter., NTT East continues to emphasize failure at closure connections.
Also, network termination equipmentInternet service providerBandwidth is being shared by more subscribers within the network...For example, NTT East's PPPoE connection uses a large number of PPPoE network termination devices, with 20 Gbps shared by 1 sessions for C-1,600 network terminators and 10 Gbps shared by 16,000 sessions for E-type network terminators. (1kbps per session)..On the other hand, this bottleneck does not exist because the IPoE connection does not use the PPPoE network termination device and shares a small number of large-capacity gateway routers as a whole..
Also, the communication speed is in the houseLocal area network It can also be affected by the quality of (LAN) communication equipment and cables, and radio / electromagnetic conditions.In the house無線 LAN(Wi-Fi) Equipment can be replaced by yourself because no qualification as a wireless operator is required., Replacement of home LAN wiringElectrical workerIt is possible to do it by yourself because you do not need the qualification ofHowever, it is not progressing, and the "Internet Traffic Study Group" of the Ministry of Internal Affairs and Communications is scheduled to carry out "implementation of enlightenment activities for improving the communication environment in apartment houses and homes"..
Japan's optical communication speed is deteriorating year by year, ranking third in the world in the 2010 Akamai survey.From the state, the Nihon Keizai Shimbun survey in 2019 shows that the nighttime speed of Japan has fallen below Southeast Asia...This is also affecting business services. For example, in May of the same year, Sega and Bandai Namco Technica announced a malfunction of the arcade game chassis due to the deterioration of the communication environment.In addition, in August of the same yearWindows UpdateThen, congestion occurs in each communication company and communication failure occurs., It has led to actual damage such as the inability to use electronic money and credit card authentication at some stores..
Announced in 2021Tokyo Institute of TechnologyAccording to the results of the communication speed survey by the iNonius project ofPPPoEAbout 12% of connections,IPoEAbout 4% of the connections were downlink 20 Mbps or less, and about half of them were downlink 10 Mbps or less..
Mobile communication speed
Since the Ministry of Internal Affairs and Communications has set guidelines for the effective speed of mobile communication, each company has released it since December 2015...The following is based on the data released by each company as of November 2021 (green is over 11 Mbps, red is less than 100 Mbps):
|Careers||Effective downlink speed (Mbps)||Effective upstream speed (Mbps)|
|Maximum value||75% value||Median||25% value||minimum value||Maximum value||75% value||Median||25% value||minimum value|
|NTT DoCoMo (Android)||430||299||237||168||13||62||45||35||23||2|
|NTT DoCoMo (iOS)||548||298||221||154||3||61||38||30||21||2|
Services for low latency are relatively possible even via the Internet, where priority communication functions cannot be used with broadband.However, the problem of latency still remains, and wireless communication becomes a problem especially on the access line side.
Half-duplex communication and latency
There are two types of communication: full-duplex communication, which allows bidirectional communication to flow simultaneously, and half-duplex communication, which allows only one-way communication to flow.
In half-duplex communication, time-division duplex (TDD / ping-pong transmission) is performed, which divides a single frequency into time divisions to bring it closer to full-duplex communication.However, since it is necessary to provide a protection period (guard period) according to the transmission distance when switching between uplink communication and downlink communication, there is a trade-off relationship that increasing the ping-pong speed for latency reduces the throughput.
In wireless transmission, time division duplex (TDD), which communicates half-duplex at a single frequency, has a radio path for transmission and reception than frequency division duplex (FDD), which separates uplink and downlink frequencies for full duplex communication. TDD is often used especially in the high frequency band where there is little wraparound because it is convenient to match.In mobile communication, carrier aggregation (LTE TDD-FDD CA) that combines TDD with FDD has appeared since 4GPP Release 3 of LTE Advanced of 12G., The problem of latency for half-duplex communication has been alleviated.
Also, as of 2022, single-frequency full-duplex communication (SFFD) and sub-band full-duplex communication (SBFD), which perform full-duplex communication at single frequency or frequencies different from sub-band by self-interference elimination in wireless transmission, Technology is under development (5G-Advanced SBFD)Such).
|TCM-ISDN||Euro-ISDN||ADSL||DOCSIS 3.1 or earlier||DOCSIS 4.0||FTTH||FDD-LTE||5G NR FDD||TD-LTE||5G NR TDD||5G-Advanced SBFD (planned)|
|Transmission line||2-wire telephone line||HFC(Combined use of optical fiber / coaxial cable)||Optical fiber||wireless|
|Duplication[Note 11]||Time division||Single frequency||Frequency division||Single frequency||Frequency division||Frequency division||Time division||Subband|
|フ レ ー ム[Note 12]||2.5ms||Full double||5ms / 10ms[Note 13]||? ~ 10ms||Full double|
|Retransmission request||None||None[Note 14]||None||4ms||0.57ms etc.[Note 15] ||4 ~ 13ms||? ~? ms||?|
Packet loss and latency
In a part of the transmission lineWhen (packet loss) occurs, the entire transmission linePacket retransmissionIs required and causes a large delay.
Packets overflow with relay equipment on high-quality transmission linesconvergenceCauses packet loss. As of 2022Then, congestion control is performed by detecting packet loss (Loss-based method; な ど) Is common, and congestion control is performed by detecting the delay caused by the concentration of packets (Delay-based method; BBRな ど) Has only been partially used.This is because BBR is always mildBufferingThis is because it is vulnerable to relay equipment that causes delays (improved version of BBRv2 is under development)...However, the TCP protocol has ECN (ECN) that notifies the congestion of relay devices.) Also exists, and its use is widespread.
On the other hand, in a poor quality transmission line, the transmission line itself causes packet loss, but the transmission data is encoded.Forward error correctionDo (FEC) or (RS sign-Turbo code-LDPC codeEtc.), local retransmission (Automatic repeat request) Or (VDSL G.fastDTU[Note 16], LTE / 5G NR HARQ, etc.) and other mechanisms to prevent packet loss are in place.
Also, the cause of packet loss in wireless transmissionMultipath propagationAlthough there are some, this multipath propagation isDiversity,Orthogonal frequency division multiplexing (OFDM) In addition, the drawback of being vulnerable to the phase noise of OFDM has been alleviated by phase tracking (such as PT-RS of 5G NR).
However, as of 2020, the packet loss rate and delay of 5G services still have room for improvement..
According to QTnet, latency of 30ms or less is required to play the game without lag..The physical distance between communications is also important for latency, as the speed of light in optical fiber is limited.
According to the speed measurement site "Minna no Net Line Speed", as of May 2022, optical lines are the only line type with an average latency of less than 5 ms for all users...Also, in the world catalog of the Internet speed measurement site Speedtest by Ookla, the median and average latency of Japanese mobile lines as of April 2022 exceeds 4 ms., Median and average of fixed broadband lines are below 30ms.
Also an internet measurement platformAccording to IIJ's research using open data from Japan, Japanese operators have a large difference in latency between non-crowded hours and busy hours as of 2020., IIJ speculates that this difference is due to congestion at PPPoE's network termination device..
Deployment in Japan
JapaneseMinistry of Internal Affairs and CommunicationsIs "Broadband serviceWaitFTTH (including FTTB) andCable TVStatistics on Internet connection services such as (coaxial / HFC) are published.In addition, fixed-type services with a downlink speed of 30 Mbps or more are treated as fixed-type ultra-high-speed broadband services.
The number of fixed Internet service contracts in Japan is as follows as of the end of June 2021. :
|The number of households|
(As of 2022 month of 1)
|Whole fixed system||FTTH|
(Coaxial / HFC only)
|(A) DSL||Fixed radio|
The Ministry of Internal Affairs and Communications wants to further promote equipment competition and service competition, but it has been weak.
- Lack of killer applications
- Many people who need fixed broadband services have already signed up, and killer applications have been regarded as important for expanding demand.After that, 4K TV became widespread and became in demand.4K broadcastingCan't catch up, High-quality Internet video distribution services are growing.
- Large capital investment
- The main optical cable has already been laid on a large scale, leaving only remote areas.Although laying in remote areas requires a lot of cost and time, optical cables are used for high-speed mobile communication and IoT (IoT).Internet of Things) Is also necessary for the backbone, so subsidies are being used to improve remote areas.
- On the other hand, the cost of investing in the backbone of the Internet is increasing as the distribution of large-capacity videos and games grows.
- Lack of IPv4 address
- The IPv4 global addresses required for mainstream IPv4 communication are already exhausted, and IPv4 addresses can be transferred from overseas, such as DS-Lite.Carrier grade NATThe life of IPv4 continues to be extended by sharing the IPv4 address with multiple people.But UDP-basedHERE CUsedHTTP / 3Due to the widespread use of IPv4, problems such as NAT table overflow and SPI table overflow have occurred., It is desirable to move to IPv6.
History in Japan
From 1999 to 2000, services for general individuals such as ADSL, CATV, and FTTH were started in urban areas and gradually started to spread. Until thenLeased lineOther than the above, inexpensive internet connection methods that can be connected all the time except for a fixed amount are available only during limited hours at night.NTTSubscriber phoneLine ofDial-up connectionbyTele HodaiThere was only means using.
East and West NTT in October 1999,ISDNIf you pay a flat rate on the line, you can use the "I Plan", which is a quasi-flat rate system that allows you to use the call charge up to the upper limit of the flat rate, and in June 2000, the "I Plan"IP connection service (FLET'S ISDN)Has started to be deployed on a nationwide scale.
In January 2001, the countrye-Japan strategyIn October of the same year, the Ministry of Internal Affairs and Communications launched..Under this concept, it was planned to combine high-speed FTTH and inexpensive xDSL / CATV to create a broadband environment for 2005 million households by 4,000...With the start of government subsidies for network construction, broadband deployment to rural areas, which had been stalled until then, gained momentum, but the number of FTTH contracts was sluggish even in FTTH service areas.In addition, even the cities, towns and villages with a small population continued to not provide even ADSL, let alone FTTH..
In some local governments, the development of cable TV (CATV) and broadband are spreading by local governments, and even in depopulated areasTo a certain extentNow available. In the maintenance of CATV, the national and local governments often subsidize the backbone lines (optical fibers), service lines, and subscription fees that make up HFC (FTTN), and in prefectures,National road,Prefectural roadFTTH/FTTx and CATV (HFC/DOCSIS) are widely spread over the world with optical fibersMunicipalitiesAlso started to appear.On the other hand, there are differences such as delays in response depending on the local government, and there are many areas where maintenance is not done at all in depopulated areas and areas around urban areas.Information gapWas occurring.
In 2004, the Ministry of Internal Affairs and Communications launched the "Broadband Zero Area Escape Plan", Announced "Next Generation Broadband Strategy 2006" in 2010.In this strategy, the goal was to increase the household coverage rate of broadband to 2010% and the household coverage rate of ultra-high-speed broadband centered on FTTH to 100% by 90...In the same year, the "Survey Study Group on Wireless Access Systems for Eliminating Broadband Blank Areas" was held at the Hokuriku General Communication Bureau of the Ministry of Internal Affairs and Communications.In 2007, the "Survey Study Group for Promoting Broadband in Unfavorable Areas" was established at the Okinawa General Communications Bureau..
In 2010, the country saidPath of lightWith the goal of "aiming for 2015% (ultra-high-speed) broadband utilization rate by 100", we planned to reduce the cost in order to raise the low utilization rate of FTTH.However, it was unrealistic and failed due to the backlash of each company. In 2011, the Ministry of Internal Affairs and Communications was established, and the fixed telephone network will be converted to IP by 2025, which is the useful life of the core network of the NTT fixed telephone network. At the same time, the fixed telephone access line will be converted to FTTH. It was decided to be considered slowly.
In 2019, the Ministry of Internal Affairs and Communications will announce the 5th generation mobile communication system (5G) and IoT (IoT) in disadvantaged areas.Internet of Things) Started "advanced wireless environment maintenance promotion project" to support the laying of optical fiber cables required for backhaul lines of base stations (Financial resources areRadio usage fee) After that, the "ICT Infrastructure Regional Development Master Plan" was launched, and the development of optical fiber for home use was promoted as a side to the development of 5G and IoT infrastructure... In 2020, the "Study Group on Broadband Infrastructure" was established to make broadband a universal service..
In the same yearNew coronavirusbyCoronaAs a result, the development of optical lines was advanced to promote telework and distance education... In 2021, the country plans to increase the coverage of optical lines to 2030% by 99.9.Digital rural city-state conceptLaunch, In 2022, the Ministry of Internal Affairs and Communications announced the "Digital Rural Urban National Infrastructure Development Plan".
Optical connection (FTTH)
FTTH is a connection method that connects everything from the base station to the house with optical fibers.The maximum speed of FTTH in the early days was about 10 Mbps.However, since then, the speed has been increased to 1 Gbps or higher.
As of the end of December 2015, the number of FTTH contracts was 12 million (up 2,758% year-on-year).However, after the end of ADSL and the corona disaster, the number reached 2020 at the end of September 9..
Super fast in specs in the late 2010s5GIn order to counter the advent of mobile communication, the number of home-use 10Gbps fixed-line communication services increased ahead of that...2015 in JapanNURO light 10G preceded, thenau Hikari Home 10 Giga / 5 Giga(2018), eo Hikari Net 10 Giga Course / 5 Giga Course (2019),FLET'S Hikari Cross(2020) and so on are appearing in succession.
VDSL (telephone line wiring) method
VDSLFrom the premises to the houseStructured cablingOld can't draw fiber opticshousing complexIt is used in such as.This is often done by connecting the inside of the building with an optical fiber and using a telephone line (metal cable) to the inside of the house.The data that goes through the telephone lineOrthogonal frequency division multiplexing In (OFDM)Digital modulationIs done.
新 し いG.fastBy using the standard, relatively high-speed communication is possible, and from 2018 in Japan, au will use it to 664 Mbps downlink / 166 Mbps uplink "au Hikari Mansion Type G".Offers (UR City OrganizationThere is also "au Hikari Mansion Urban Organization G" for rental housing in Japan).
On the other hand, NTT's "FLET'S Hikari Next Mansion Type (VDSL method)" is said to have about 2019 million contracts as of 200.However, it is as slow as 100 Mbps at maximum...Therefore, in July 2020 during the corona disaster, NTT made the conversion from VDSL wiring to optical wiring (FTTH) free of charge, and is promoting the conversion of premises wiring to optical wiring..
LAN wiring method
The LAN wiring method is the same as above.housing complexIt is used in.This is connected to the inside of the building with an optical fiber, and by the inside of the houseLAN cable(Baseband transmission) is used.Each house is the sameLocal area network Since there is a security problem if it belongs to (LAN),Virtual LAN The LAN of each house is divided using (VLAN)...However, the text from the VLAN device to the inside of the house is plain text (non-encrypted text).
Since the LAN wiring method does not require home equipment, it is mainly used in all-unit collective condominium ISPs.As of the end of March 2020, it is said that there are contracts for 3 thousand units for all-unit collective condominium ISPs.(Including VDSL method etc.).In addition, NTT offers "FLET'S Hikari Next Mansion Type (LAN wiring method)" and KDDI offers "au Hikari Mansion Type E".
As of the end of December 2021, the number of mobile communication contracts has risen to about 12 million...However, there are also regional disparities.Villages outside the area where mobile communication signals do not reach are scheduled to be eliminated by the end of 2023, but only 95% of the national roads under direct control within the area are..
In addition, not only in depopulated areas, but also in the surrounding areas of urban areas, the frequency band (number of bands) provided is small, and the density of base stations is low, so the connection speed is often low.Platinum bandAlthough each company provides (700MHz-900MHz band) with a population coverage rate close to 100%, other frequency bands have not reached that level of coverage... NTT DoCoMo offers "LTE (by speed)" on the area map.
Optical fiber is basically used for the backhaul line for wireless access, but flexible fiber is used even in areas where optical fiber lines are not provided.It is possible to provide ultra-high-speed services by micro-wireless relay at speeds comparable to those of optical fibers (such as 5G at the summit of Mt. Fuji).However, in some areas slow micro radio relay and satellite communicationsThere are also base stations that use the as a backhaul line.
The number of wireless Internet service contracts in Japan is as follows as of the end of December 2021. :
(As of January 2022)
|Public wireless LAN||5G||3.9G / 4G||3G||BWA||Local 5G|
|the way||Radio band|
|LTE-A (4G) /|
|700/800 / 900MHz band|
1.5 GHz band
1.7 GHz band
2 GHz band
3.4 GHz band
AXGP (LTE compatible)
|2.5 GHz band|
|1.9 GHz band|
|5G||2.3GHz band (planned)|
3.7 GHz band
4.5 GHz band
28 GHz band
|(5G additional candidate)||(2.6GHz band)|
|Local 5G||4.7 GHz band|
28 GHz band
|Public wireless LAN||2.4 GHz band|
5 GHz band
6 GHz band
60 GHz band
|5GHz wireless access|
(High output wireless LAN)
|4.9 GHz band|
|Fixed micro line|
|6 / 6.5 / 7.5GHz band|
11 / 15 / 18GHz band
22 / 26 / 38GHz band
70 / 80GHz band
|Communication satellite||Ka band|
Wireless LAN method (Wi-Fi 4 or later, IEEE802.11n / 11ac / 11ax)
August 2009, 4,Wire and wirelessIs a public wireless LAN service that uses IEEE 802.11n "Wi2 300To start, KDDI and Okinawa Cellular responded to its roaming on June 2011, 6.au Wi-Fi SPOTStarted.. From May 2013, 5, docomo will be "docomo Wi-Fi"("d Wi-Fi"Predecessor) to support IEEE802.11n, From April 2014, 4, Softbank also said "BB mobile pointStarted to support IEEE 802.11n.
In addition, a design guideline for 2010GHz wireless access (71GHz band) has appeared in the domestic standard ARIB STD-T5.1 5 version for wideband mobile access systems in 4.9., The use of high-speed IEEE 5n has advanced even for long-distance 802.11GHz wireless access.This is IEEE 802.11j / n, IEEE802.11n / j, IEEE802.11njAnd so on.
Mobile communication (5G)
5rd generation mobile communication system (5G) is the successor to 4G, and 5G has higher frequencies than 4G (Sub6 band andMillimeter waveHigh speed is realized by using a wide band (band). 5G's new wireless interface5G NRIt is also possible to convert the frequency bands of 3G, 4G, and BWA, which have a narrow band but easily spread radio waves, to 5G NR and use them (5G diversion).
From 2020, each mobile company started official 5G service.In addition, regional BWA 5G NR (BWA 5G NR) has been possible since the same year.。2022年冬にはUQワイコミュニケーションもUQ WiMAXの周波数帯を5Gに転用する予定となっている.
Wireless broadband connection during migration
Mobile communication (4G)
Takeover of WILLCOM's assets from 2011Wireless City PlanningAs the successor to XGPTD-LTECompatibleAXGPTo start, The AXGP network is from SoftbankSoftBank 4GWas also used.Also, since 2013, UQ will be compatible with TD-LTE as a successor to WiMAX.WiMAX 2.1 Based on AEWiMAX 2+To startIn 2014, the ban on TD-LTE compatible AXGP method and WiMAX 2.1 AE method was lifted in the regional BWA as well... With TD-LTE compatibility, carrier aggregation between these services and LTE-Advanced (4G LTE) is also possible..
Also, in 2014, SoftBank will use the AXGP line as the back end to connect wired LAN and wireless LAN clients.SoftBank AirAlso appeared.
The LTE-Advanced adoption service then became compatible with 5G NR.
Wired broadband connection during migration
FTTN connection (DOCSIS 3.0 or later)
DOCSISBy FTTN (HFC: Hybrid Fiber Coaxial) Connection is mainly used for internet connection of cable TV service.This FTTN (HFC) utilizes the existing coaxial cable that is easily attenuated at the end, but it is of high quality at the core part.Optical communicationAdoptingCarrier-to-noise ratioIt is to earn (C / N ratio).
DOCSIS 3.0 or later bundles multiple communication channelsChannel bondingWas introduced, and by increasing the frequency band used for communication, it became possible to significantly increase the speed. In August 2006, DOCSIS 8, which can achieve a maximum downlink of 1 Gbps / maximum uplink of 100 Mbps, was introduced, and in October 3.0, DOCSIS 2013, which can achieve a maximum downlink of 10 Gbps / maximum uplink of 10 Gbps, was introduced.However, unlike wideband optical cables, narrow-band coaxial cables have a problem with the range of frequencies that can be passed.The maximum frequency that can be used according to the standard is DOCSIS 2.5 up to 3.1 MHz., Although it rose to 3.1Mhz in DOCSIS 1794, Japanese household equipment is not guaranteed to pass frequencies above 770MHz used in terrestrial digital broadcasting., And even if you can pass up to 1794Mhz, Japan BS-IF / CS-IF frequency band Since it collides with (1032 to 3224MHz), there is a problem of collision due to wraparound of BS digital broadcasting / CS digital broadcasting signals in buildings where BS / CS antennas are installed.As of March 2017, it was common for Japanese cable TV to use the band up to 3MHz...Therefore, it was difficult to get the full speed of the specifications.
For example, J: COM started a service using DOCSIS 2007 in Kansai in September 9 and in Kanto in October of the following year, but a service with a maximum downlink speed of 10 Mbps and a maximum uplink speed of 3.0 Mbps ("J: COM NET Ultra" → " 160M course "), Even after the speed increase in January 2015, the maximum downlink speed was 1 Mbps and the maximum uplink speed was 320 Mbps ("10M course")..
After that, at J: COM from January to April 2015Digi-ana conversionEnded analog broadcasting by, Starting with "J: COM Kumagai / Fukaya" in October 2017Introduced a service using DOCSIS 3.1, which finally increased the nominal speed to 30 Mbps.[Note 17]Reached a service with a maximum downlink speed of 1 Gbps and a maximum uplink speed of 100 Mbps ("J: COM NET 1G course").
In addition, speeding up with FTTN (HFC) is more susceptible to noise.,Full dual communicationThere is an oscillation problem of the amplifier inTherefore, it is necessary to expand the optical section, and in addition,New 4K8K satellite broadcastingDue to the problem of insufficient bandwidth for retransmission, more and more cable TV companies are switching to providing services via optical line (FTTH). Cable Labs, which has established the DOCSIS standard, has also prepared his DPoE (DOCSIS Provisioning of EPON), which adds DOCSIS operation management functions to passive optical network (PON) -based FTTH lines.
Japan Cable Television FederationThe technical committee of Japan launched the "Transmission Line Advancement Task Team" in 2017 to support the conversion of cable TV lines to FTTH.In addition, in 2017, the Ministry of Internal Affairs and Communications started the "Cable TV Network Optical Promotion Project"., In 2018, "Disaster resistance enhancement project by cable TV opticalization" was started, and the target of FTTH was set to "about 2025%" by the end of 50 (2019% as of the end of 26.6)... In fiscal 2019, "Emergency Measures for Cable TV Operators to Convert to Optical Cables" was also started.(However, this subsidy is limited to the part used for broadcasting purposes.).In addition, subsidies for the "advanced wireless environment maintenance promotion project" can be used for communication purposes, and in some local governments, "temporary subsidies for regional revitalization for new coronavirus infections" are also used for the conversion of cable TV. (Tottori CitySuch).
However, there are still some businesses that have left the old FTTN (HFC) equipment.As of the end of December 2021, the number of contracts for the Internet using coaxial / HFC was about 12 million, and the prefectures with the largest number of contracts were Tokyo, Osaka, and Kanagawa in that order...Therefore, as of 2022, J: COM will not include the upstream nominal speed in the "broadband quality standard" at the "Study Group on Broadband Infrastructure" of the Ministry of Internal Affairs and Communications, and will make it "only the downlink nominal speed". Claims to be "nominal speed in protector" rather than nominal speed in modem.
Past wired broadband connection
FTTB connection (coaxial wiring method)
Coaxial wiring is also used in apartment buildings."C.LINK" ("c.LINK") that uses the blank frequency between terrestrial digital broadcasting and BS / CS digital as a standard corresponding to the coaxial cable on which the TV broadcast wave rides.There is a specification called (predecessor of)In 2005, J: COM used its c.LINK to provide "J: COM NET Hikari".It has been canceled.
MoCA 2006 with a maximum of 135 Mbps was standardized in 1.0, and then MoCA 2010 in 2.0 supports a maximum of 1 Gbps, MoCA 2016 in 2.5 supports a maximum of 2.5 Gbps, and the planned MoCA 3.0 supports a maximum of 10 Gbps.HoweverJapan Cable LaboratoriesAccording to 2015, there are no known examples of MoCA use in Japan..
FTTN connection (DOCSIS 1.0 / 1.1 / 2.0)
The first DOCSIS 1.0 appeared in 1997 as a standard with a maximum downlink speed of 42 Mbps and a maximum uplink speed of 10 Mbps.In Japan, in 1999, a cable TV companyJ-COMand riceJointly at Home Japan (laterAt Net Home) Launched, At Home Japan began to provide CATV Internet service "J-COM @ NetHome" (later "J-COM Net") on the J: COM cable TV network from June 2000.However, the speed is low for both downlink and uplink, and even after the speed increase in July 2001, the maximum downlink speed is 7 Mbps and the maximum uplink speed is 2 kbps., Even after the speed increase in February 2002, the maximum downlink speed was 2 Mbps and the maximum uplink speed was 8 Mbps..
2003 yearsInternet associationAccording to a survey by J: COM, J: COM had the top share of CATV Internet.However, when a service with a maximum downlink speed of 2002 Mbps such as "Yahoo! BB 12M" appears in 12 with inexpensive ADSLThe CATV Internet, which was expensive and had a maximum downlink speed of 8 Mbps, became inferior in terms of catalog specifications...Therefore, J: COM is in some areas (TokyoHigashimurayama city) Was used for FTTH conversion experiments.However, the realization of TV broadcasting services on FTTH was still difficult at that time., J: COM went on to introduce DOCSIS 2.0 instead.
In 2007, J: COM introduced the next generation of DOCSIS 3.0, but it is technically backwards compatible.After that, "1M course", "12M course", "24M course" and "40M course" were continued for a long time, but the low speed course gradually disappeared due to the subsequent speed increase of the billiard type..
ADSL communicates from the base station to the house with a metal cable.
ADSL specifications with a maximum downlink speed of 1999 Mbps and a maximum uplink speed of 8 Mbps in 1.3 (G.dmt) was formulated. In 2001, a high-speed ADSL service with a maximum downlink speed of 8 Mbps was launched.Yahoo! BB,ACCA NetworksAppeared moreThe following year, in 2002, many services with a maximum downlink speed of 12 Mbps appeared beyond the standard.After that, the speed has continued to increase rapidly, reaching a maximum downlink speed of 2004 Mbps and a maximum uplink speed of 50 Mbps in 5..
However, after that, the speedup stopped, and the number of contracts began to decrease from the April-June period of 2006, decreasing at a pace of about 4% every quarter.2008At the end of March, the number of households using optical lines exceeded the number of households using ADSL lines for the first time.The number of users, which used to be more than 3 million, has decreased to 1500 million at the end of June 2017, which is about 6% of the peak..
Due to deterioration of facilities and deterioration of profitability,Telephone officeSome line operators have terminated the ADSL service on a unit basis... NTT will also end the FLET'S ADSL service in the "FLET'S Hikari" service area on January 2023, 1..
Past wireless broadband connection
Wireless LAN method (Wi-Fi 1, IEEE802.11)
2001Since AprilTEPCO-Softbank-MicrosoftThe joint venture Speednet will make the last mile a 2.4GHz band IEEE 802.11 (FH method) wireless LAN communication.Speednet wireless access serviceStarted..However, due to the problem of radio wave interference, it was not possible to move to high-speed IEEE 802.11b.Therefore, it cannot keep up with the speeding up of wired communication., Ended service on May 2006, 5.
Wireless LAN method (Wi-Fi 2, IEEE802.11a / 11b / 11j)
NTT Communications ThePublic wireless LANAfter the service experiment "Hi-FIBE", the commercial service "Hi-FIBE" adopted on May 2002, 5, which adopted IEEE15b in the 2.4GHz band and IEEE802.11a in the 5GHz band.Hot spotStarted..In addition, Softbank also started the pilot public wireless service "Yahoo! BB Mobile" (one of the predecessors of "BB Mobile Point") that adopted IEEE2002b from April 4, 24., NTT DoCoMo also adopted the public wireless LAN service "IEEE2002b" on July 7, 1.Mzone(Later "docomo Wi-Fi") started..Japan Telecom (SOFTBANK TELECOM(Predecessor of) also started "Mobile Point" (one of the predecessors of "BB Mobile Point") adopted by IEEE2004b on April 4, 1..
In addition, on December 2003, 12, TEPCO adopted the 1GHz band IEEE 5a as the successor to Speednet.TEPCO Hikari Mansion Type 5GHz Wireless Plan(Later "Hikari one Mansion Type Wireless")(Ended 2011).
In addition, 5GHz wireless access is assigned to 4900-5000MHz (4.9GHz band) and 5030-5091MHz (5.03GHz band, deleted in 2017) in the 5GHz band., 2004 for 5GHz wireless accessHigh output wireless LAN (IEEE 802.11j) Was formulated, and 5GHz wireless access by registered stations using it appeared.For thisOrrence"Skynet V(Hokkaido), Waikomu"Air 5G" (Hokkaido),NTT Business SolutionsThere are consignment operations such as "Whale Net", "Painushi Manet", and "Ginoza BB" (Okinawa Prefecture).
Since then, the Wi-Fi Alliance has been a Wi-Fi access point since 2013 and an old and weak encryption method with Wi-Fi clients since 2014.WEPAnnounced to ban.. NTT Communications' "Hotspot" service ended on December 2012, 12, Successor service "OCN hotspotBut at the end of July 2013, the spot area of the old hotspot was deleted...Also, docomo Wi-Fi also deleted the old access point on September 2013, 9..
Wireless LAN method (Wi-Fi 3, IEEE802.11g)
From July 2004, SOFTBANK BB began supporting IEEE 7g for the public wireless LAN service "Yahoo! BB Mobile"... On December 2004, 12, NTT East adopted the IEEE 1g public wireless LAN service "FLET'S SPOTStarted.. September 2005, 8Live doorLaunched "livedoor Wireless", a public wireless LAN service that uses IEEE 802.11g.
"Livedoor Wireless" was discontinued on April 2013, 4.
Submillimeter wave / millimeter wave band FWA
Originally, the 26GHz band and 21GHz band were used for digital subscriber radios. In 1985, NTT started 26SS-D26 digital subscriber radio using the 1GHz band.[Note 18], In 1987ShindenとInternational telegraph telephone21GHz band is open to.
In April 2002, NTT East used the 4GHz band for condominiums where wired installation was difficult.B FLET'S FWA type(Later "B FLET'S Wireless Access Type").. In 2004, NTT West used the 26GHz band for households with difficult wired connections.B FLET'S Wireless Family TypeStarted.
After that, about 26 stations were operated in the 5300GHz band, centering on mobile phones and BWA entrance lines.However, the 26GHz band is a 5G frequency candidate., The use of those 26GHz bands is also being considered for frequency transition and sharing..
Mobile communication (3.9G)
Standardized as fixed wireless accessWiMAXFor mobile communications in 2005 as a derivative ofMobile WiMAX(3.9GOne of the standards) has appeared, and in Japan the standard has been available since 2008.Region BWAIt came to be used as. In 2009Mobile WiMAXAdoptHigh-speed mobile flat-rate communication service OfUQ WiMAX(UQ Communications) Has also appeared.Also, in the same year, it was an original standard.XGPHigh-speed mobile flat-rate communication service that adoptedWILLCOM CORE XGP(WILLCOM) Has also appeared.
Since the spring of 2011, au has been in-house3GUQ WiMAX network can be used in addition to network+ WiMAXServices and their correspondingSmartphoneAnd at the same time thatTetheringWas released for free. afterwards,NTT DoCoMo,Softbank mobileWith a smartphoneLTEOpened tethering with (3.9G) support.
Various services that adopted LTE subsequently adopted 4G LTE-Advanced technology.In addition, WILLCOM CORE XGP that adopted XGP ended on January 2012, 1., UQ WiMAX with mobile WiMAX ended on March 2020, 3.
Areas not provided with broadband
As of March 2021, the remaining 3 (39%) households in Japan have undeveloped optical fibers...The main areas where FTTN connection, relay, ADSL, etc. are used for communication without reaching the optical fiber are as follows..
- Remote island
- NiigataIwafune-gunAwashimaura Village(Awashima）
- KagoshimaKagoshima DistrictToshima Village(Vassal archipelago）
- OkinawaShimajiriMinamidaito Village(Minami Daito Island)/Kitadaito Village(Kitadaito Island）
- NaganoShimoina DistrictMakimura/Taifu Village
- NaraYoshino-gunTenkawa Village
- HiroshimaYama prefecture countyKitahiroshima Town
- HiroshimaSera-gunSera Town
- Yamaguchi KumageUeseki Town
- Yamaguchi Abu-gunAbu Town
In addition, the following are areas where the undeveloped household rate exceeds 50%.
- MiyazakiNishimori prefecturePlateau town
- OitaKunisaki City
- KochiTosa DistrictOkawa Village
In addition to the above, remote islands where optical fiber does not passLonely islandThere are many (in Hiroshima prefecture)Nasake IslandSuch). As of March 2021, 3% of households living on remote islands are unable to use optical fiber..
Mobile phone line
As of March 2021, there are 3 out-of-area settlements on Japanese mobile phone lines, and the remaining out-of-area population is about 876., It is planned to eliminate the out-of-area population by the end of 2023.
In addition, there are still many tunnels where mobile phones cannot be used.Undeveloped sections have been eliminated in the Shinkansen tunnel of the railway, Sections with a large average number of people passing through conventional line tunnels (109km or more out of 17km)) Is being maintainedHowever, other than that, there are still undeveloped sections.As of the end of 2018, about 2% of expressways and about 5% of directly controlled national roads are undeveloped sections of road tunnels..
Nihon Hyaku Meizan（Japan's hundred famous mountains）High-speed mobile communication of each company is becoming available even on mountain trails of popular mountain climbing spots such asIt is also recommended to use multiple carrier lines with dual SIM just in case...Although high-speed mobile communication has made it possible to upload videos and distribute live even in the mountains, there are still sections where the communication speed is slow and where radio waves do not enter.
FarmlandIn, 95% or more is inside the mobile phone cover, but depending on the prefecture, 5% or more of the agricultural land is not covered (according to the estimation by the Ministry of Agriculture, Forestry and Fisheries in 2022)..
At the hospitalEnd of PHS serviceAlthough the number of places where mobile phones can be used is increasing, it is said that the improvement of the radio wave condition of mobile phones is delayed in small hospitals...In addition, some high-rise condominiums also have mobile phone radio wave problems...JTOWER and others are installing indoor equipment for mobile phones.However, there are some places that have not been installed yet.
At sea, the number of places where mobile phones can be used is increasing in the sea near where radio waves from land reach..
Global Broadband Internet Penetration
|Ranking||Country||Ratio of broadband subscribers to 100 people||Number of contractors (person)|
|DSL||Cable TV||FTTH||satellite||Fixed radio||Other||Total|
- ^ Physical deterioration due to oxidation of cables and amplifiers,4K / 8K broadcastingIncluding both social deterioration due to lack of bandwidth due to the spread of
- ^ Another predecessor of au Hikari, "KDDI Hikari Plus," uses NTT's dark fiber.
- ^ Although Multipath TCP itself was implemented earlier in iOS 7, its use is in voice assistants.CrabWas limited to
- ^ BS1 to BS23
- ^ ND1 to ND26 (ND25 and ND26 are unused as of 2021)
- ^ C13 to C63 (TV Frequency Channel # Cable Television Broadcasting）
- ^ When 3 APSK of the ISDB-S16 method is used (advanced BS digital broadcasting that realizes 8K broadcasting and multiple 4K broadcasting).In the ISDB-S3 system, 120APSK of about 32Mbps is also specified, but it is not used as of 2022 due to the problem of non-linear distortion in the satellite repeater.
- ^ When using 256QAM of the ISDB-C method.note thatCarrier-to-noise ratioMany cable TV companies stay at about 64 Mbps of 29QAM due to the problem of (C / N ratio), and in that case, 4K broadcasting requires multiple physical channels per logical channel.(J.183 expansion method, etc.).The J.382 method also specifies 59QAM at about 4096Mbps.
- ^ There are two types of 5G broadcasting: large cell system and small cell system.
- ^ Although there is a priority communication function by QoS in the NGN network, its use is limited to some paid services such as "Hikari Denwa" (including "Data Connect") and "Hikari TV".
- ^ Red for time division, yellow for combination of radio and frequency division, green for combination of wired and frequency division, and green for subband full-duplex communication or single-frequency full-duplex communication.
- ^ The frame here is a set of downlink → switching → uplink.
- ^ 5ms is for DSUxx DSUxx configuration
- ^ G.2 exists in the extension of ADSL2 / ADSL998.4 +.
- ^ 0.57ms is for 2 OFDM symbols per TTI and subcarrier spacing of 15kHz.Different in other configurations.
- ^ DTU was originally intended for ADSL2 / ADSL2 + / VDSL2International Telecommunication Union It is included in G.998.4 (G.INP) standardized by (ITU).BroadcomBased on the vendor extension PhyR.
- ^ Definition of "ultra-high-speed broadband" in "Next Generation Broadband Strategy 2010" (#Definition of speedreference)
- ^ Uses equipment made by NEC
- ^ a b Federal government's series of broadband-related subsidies Foundation for MultiMedia Communications November 2021
- ^ BROADBAND --FCC Should Analyze Small Business Speed Needs p.23 (Page 19) US Board of Audit July 2021
- ^ a b The Future Is in Symmetrical, High-Speed Internet Speeds (English) Electronic Frontier Foundation April 2021, 7
- ^ Narrow band ITmedia
- ^ ISDN's "digital communication mode" will end in January 2024, and companies should immediately check and take measures! JISA releases new version of countermeasure guidelines Impress February 2018, 5
- ^ ADSL de facto "end declaration" major communication, 1 million user transfer battle (4/XNUMX page) Sankei Shimbun March 2015, 8
- ^ Information and Communication Comprehensive Catalog 2021-2022 --FTTH Promotion Project Furukawa Electric September 2021, 9
- ^ Notice of cable TV equipment switching work TOKAI cable network
- ^ Current status of cable TV business (FY2017 financial results version) p.44 Development Bank of Japan December 2018
- ^ a b "New Media White Paper: 59 Edition" Nippon Information and Communication Corporation 1984 ISBN-978 4532085384
- ^ Naomi Fujimura "Network configuration operation theoryP.4 Kyushu University 2004/05/10
- ^ a b c Broadband ISDN (B-ISDN) and the Asynchronous Transfer Mode (ATM) Roger L. Freeman January 2002, 1
- ^ Will broadband change the world? Demonstration experiments have begun, and competition is intensifying. ITmedia July 2000, 10
- ^ a b c Federal Communications Commission FCC 99-5(word perfectFormat) p.10-11, p.13 United StatesFederal Communications Commission April 1999, 2
- ^ BROADBAND --FCC Should Analyze Small Business Speed Needs p.25 (Page 21) US Board of Audit July 2021
- ^ Understanding the FCC "National Broadband Plan" -US Strategy Aiming to Be "World's Best" Business Network May 2010, 5
- ^ World Information and Communication Situation-United States (Cash as of September 2021) p.14 Ministry of Internal Affairs and Communications
- ^ Broadband ITmedia
- ^ Marketing Glossary Broadband: Broadband JMR Life Research Institute
- ^ a b e-Japan strategy Advanced Information and Communication Network Society Promotion Strategy Headquarters January 2001, 1
- ^ 13 White Paper on Information and Communication --Chapter 1 Special Feature Accelerating IT Revolution-- 2 Spread of Broadband Access Ministry of Internal Affairs and Communications 2001
- ^ Next Generation Broadband Strategy 2010 Nikkei BP July 2006, 9
- ^ a b Path of light Nikkei BP July 2010, 6
- ^ Study Group on the Ideal Broadband Infrastructure Phase I Direction of Arranging Issues (Draft) p.6-7 Study Group on Broadband Infrastructure July 2020, 7
- ^ Final summary of the study group on the ideal way of broadband infrastructure [Draft] Study Group on Broadband Infrastructure February 2022, 2
- ^ KDDI's "Hikari Plus", menu for single-family homes and small-scale condominiums added ITmedia July 2004, 11
- ^ OTNet provides FTTH service "Hikarifuru" for Okinawa Impress February 2004, 5
- ^ FLET'S Hikari Cross Service Area NTT East
- ^ a b FLET'S Hikari Cross Service Area Confirmation / Application NTT West
- ^ a b c d e NURO Hikari 10G SONY
- ^ a b eo Hikari Net (for detached houses) --Service area OPTAGE
- ^ About the start of provision of the ultra-high-speed Pikara Hikari Net "XNUMX Giga Plan" STNet January 2022, 1
- ^ 10 giga course BBIQ
- ^ a b c d e f J: COM NET 1G / 5G / 10G course J: COM
- ^ [Final version] Kyotanba-cho cable TV privatization promotion business council explanatory material 20201130 Kyotanba Town
- ^ Cable TV Shinagawa, a FTTH service with a maximum of 10 Gbps, will be available from February 2st. Impress February 2022, 1
- ^ Notice of start of acceptance of "K Broad Hikari 10G" Kintetsu Cable Network May 2020, 5
- ^ Notice of acceptance of "K Broad Hikari 5G" and "K Broad Hikari 10G" KCN Kyoto April 2021, 4
- ^ Light 10 giga split, light 5 giga split TV Kishiwada
- ^ a b PREMIUM 4G NTT DoCoMo
- ^ a b c d Ultra-high-speed communication area KDDI
- ^ a b c d SoftBank 5G --What is the difference between SoftBank 4G and SoftBank 3G? Softbank
- ^ a b 5G NTT DoCoMo
- ^ a b AQUOS R7 Softbank in "Product Information" → "Check Specs"
- ^ Handle the traffic that explodes due to the spread of smartphones! ITmedia July 2012, 7
- ^ a b Apple opens Multipath TCP in iOS11 Tessares June 2017, 6
- ^ Establish a backup connection for iOS using Multipath TCP Apple
- ^ Special TCP used only by iOS "Siri" Nikkei BP July 2017, 4
- ^ The 594th: What is EAP-SIM authentication? Impress February 2012, 12
- ^ a b "Docomo Wi-Fi" to speed up and improve security Impress February 2013, 5
- ^ a b c About the introduction of public wireless LAN service "au Wi-Fi SPOT" next-generation wireless LAN standard "IEEE802.11ac" KDDI July 2013, 10
- ^ a b c Softbank Wi-Fi Spot Terms of Service Softbank
- ^ a b 5GHz band wireless access system Ministry of Internal Affairs and Communications
- ^ Meaning of high-throughput satellite (high-throughput satellite) NTT Resonant
- ^ a b Latest trends in satellite communication systems Ministry of Internal Affairs and Communications January 2017, 1
- ^ Tonga, South Pacific, reverts to "early net" due to submarine cable breakage Reuters April 2019, 1
- ^ Tonga's submarine cable, cut due to landslide or recovery is expected to be 3 weeks Asahi Shimbun November 2022, 1
- ^ Will fibre broadband be obsolete by 2030-and what about 5G? BBC September 2019, 11
- ^ Study Group on Broadband Infrastructure (XNUMXnd) Explanatory Materials p.7 KDDI May 2020, 5
- ^ The topic "wireless LAN cable" actually exists p.2 ITmedia July 2017, 10
- ^ HTTP Archive: State of the Web - Total Kilobytes Internet Archive in "Show Table"
- ^ September 14, 2009 - Akamai Reveals 2 Seconds as the New Threshold of Acceptability for eCommerce Web Page Response Times Akamai September 2009, 9
- ^ Web page loading time, 3 seconds is the limit - bounce rate increases sharply at 5 seconds Mynavi December 2018, 1
- ^ "Don't allow Yahoo! BB to run alone!"-There is an IP phone behind the impatience of rivals Nikkei BP July 2002, 12
- ^ a b Regarding the status of system development related to PSTN migration p.2 Ministry of Internal Affairs and Communications July 2021, 6
- ^ NTT East / West begins selling "FLET'S Phone VP1000", an IP videophone terminal compatible with FLET'S services ASCII September 2004, 7
- ^ Fretzphone VP1000 (information equipment) NTT West
- ^ Fatigue in web conferencing is caused by "poor sound quality". Verification by NTT Data Institute of Management Consulting and Shure Impress February 2022, 6
- ^ Transmission evaluation of a transmitter for nonlinear distortion compensation of a satellite repeater NHK Science & Technical Research Laboratories 2021
- ^ Trends in ultra-high-definition television broadcasting on cable TV p.10 Ministry of Internal Affairs and Communications May 2014
- ^ Information and Communication Council Information and Communication Technology Subcommittee Broadcasting System Committee (47th) --Information and Communication Council Information and Communication Technology Subcommittee Broadcasting System Committee Report (Draft) p.613 Ministry of Internal Affairs and Communications 2014
- ^ Expenses for transmitting terrestrial television broadcasts NHK July 2021, 12
- ^ # 352 A new study session started at the Ministry of Internal Affairs and Communications.How far will the discussion take place? NHK July 2021, 12
- ^ K-Opticom's efforts toward the era of integrated communication and broadcasting p.11 K-Opticom May 2006, 5
- ^ Research report on changes in the market environment for digital content p.26 Digital Conten Association of Japan March 2010
- ^ The latest status of CATV transmission technology p.12 Sumitomo Electric Industries, Ltd. December 2017, 12
- ^ Video distribution service support status in NGN NTT East / NTT West June 2018, 6
- ^ Broadcasting System Committee IP Broadcasting Working Group (2nd) Material --About IP broadcasting in FTTH p.12 Sumitomo Electric Industries, Ltd. December 2018, 5
- ^ a b c Aim of "Hikari TV 4K" leading 60K / 4p distribution Impress February 2014, 11
- ^ About MBMS standard trend survey Broadcast Service Advancement Promotion Association March 2021, 3
- ^ Study Group on the Ideal Broadcasting System in the Digital Era (XNUMXrd) -Advanced Cases of Broadcasting Infrastructure and Internet Distribution in Foreign Countries p.40 Foundation for MultiMedia Communications December 2021, 12
- ^ a b Study Group on the Ideal Broadcasting System in the Digital Age (XNUMXst) p.9 Ministry of Internal Affairs and Communications May 2021
- ^ Yajiuma Watch [2007/11/16] Impress February 2007, 11
- ^ About the simultaneous simultaneous delivery/start of missed program delivery service NHK July 2020, 1
- ^ NHK Plus will be compatible with TV from April 4st. 1-hour simultaneous delivery also started Impress February 2022, 3
- ^ Simultaneous online distribution of 4 commercial broadcasters to start in April TVer system development progress Asahi Shimbun November 2022, 2
- ^ Event traffic as seen by the ISP Kyushu Telecommunication Network January 2014, 1
- ^ Recent traffic situation Japan Internet Exchange January 2016, 1
- ^ Network neutrality from the perspective of traffic control Chubu Telecommunications January 2016, 1
- ^ a b c What are the FLET'S networks and self-defense measures for heavy traffic on Windows Update? ITmedia July 2019, 9
- ^ Launch of option "IPoE Advance" that provides 3 times the bandwidth to "OCN Hikari" Impress February 2021, 6
- ^ What is important in online games?Minimize communication delay Impress February 2019, 6
- ^ a b c About the current state of the Internet and quality measurement JAIPA February 2021, 2
- ^ a b Internet Traffic Study Group (7th) Handouts --Material 7-2 Internet Traffic Study Group Report (Draft) p.22 Ministry of Internal Affairs and Communications May 2021
- ^ System requirements-YouTube help Google
- ^ Recommended internet connection speed Netflix
- ^ Internet speed recommendations Hulu
- ^ Recommended line speed U-NEXT
- ^ The average number of people in a household is 2.27, and Tokyo is "divided into two" due to living alone and aging. Nikkei Shimbun March 2021, 6
- ^ a b Select live encoder settings, bitrate, resolution Google
- ^ AWS Elemental MediaLive Frequently Asked Questions-Can I use a relatively low bandwidth residential or remote network when using Link? The Amazon
- ^ Explanation of application for approval of change of connection agreement for Nippon Telegraph and Telephone East Corporation and Nippon Telegraph and Telephone West Corporation's first-class designated telecommunications equipment (revision of connection fee in Reiwa XNUMXth year, etc.) p.24 Ministry of Internal Affairs and Communications May 2022
- ^ Verizon: WDM-PON Still Sounds Expensive April 2010, 9
- ^ 1 Gbps per person per wavelength, the super network that NTT "IOWN" aims for Nikkei BP July 2021, 2
- ^ NTT East / West Reiwa XNUMXrd year connection agreement change approval application and unused core wire report of subscribed optical fiber p.27 Ministry of Internal Affairs and Communications 2021
- ^ "This is a double regulation."-NTT East argues head-on against antitrust violations ITmedia July 2004, 2
- ^ Review of the useful life of optical fiber cables Ministry of Internal Affairs and Communications
- ^ Toward faster troubleshooting of optical equipment in the FTTH era Business Communication 2005
- ^ Results of studies on reviewing the economic service life of optical fiber cables NTT East 2015
- ^ Main expansion menus and expansion standards for PPPoE network termination devices Ministry of Internal Affairs and Communications
- ^ Explanation of application for approval of change of connection agreement for Nippon Telegraph and Telephone East Corporation and Nippon Telegraph and Telephone West Corporation's first-class designated telecommunications equipment (change of connection menu for network termination device, etc.) p.8 Ministry of Internal Affairs and Communications May 2020
- ^ Difference between IPoE connection and PPPoE connection NTT Communications
- ^ NGN IPoE method internet connection NTT East July 2018
- ^ Is it technically suitable?Weak radio?Basic knowledge of radio wave regulations that can not be heard now Think IT February 2017, 2
- ^ I tried to DIY the home LAN to 10GbE.Replacing the entire wiring of my home is surprisingly easy !? Impress February 2021, 5
- ^ Summary of "Internet Traffic Study Group" Report-Toward Ensuring Internet Service Quality in "New Everyday Life"- p.5 Internet Traffic Study Group Secretariat May 2021, 5
- ^ Average speed of internet connection, Japan is 7.6rd place at 3 Mbps-Akamai survey Impress February 2010, 4
- ^ Japan's optical communication speed falls to 23rd place, hampering 5G Nihon Keizai Shimbun January 2019, 2
- ^ Deterioration of communication conditions in some areas BANDAI NAMCO Games May 2019, 5
- ^ Regarding the problem of communication instability with ALL.Net compatible titles Sega May 2019, 5
- ^ Regarding the problem of communication instability with ALL.Net compatible titles BANDAI NAMCO Technica June 2019, 6
- ^ Communication failure with OCN Does Windows Update increase communication volume? [Additional notes] ITmedia July 2019, 8
- ^ Internet communication speed with many complaints "slower than advertisement" ... Unification of measurement methods, establishment of expert meeting Yomiuri Shimbun May 2020, 12
- ^ Sub-working group on establishing quality measurement methods for fixed broadband services Ministry of Internal Affairs and Communications
- ^ Demonstration Report for FY2021 and Proceedings for FY2022 (Draft) Ministry of Internal Affairs and Communications January 2022, 6
- ^ 2nd Internet Traffic Study Group --Introduction of Network Measurement Project and Report of Internet Environment Evaluation p.21 Yoshiaki Kitaguchi January 2021, 1
- ^ 3 Carriers publish "effective speed" of communication-measured based on the guidelines of the Ministry of Internal Affairs and Communications ITmedia July 2016, 1
- ^ a b Effective speed measurement result (cash as of November 2021) NTT DoCoMo
- ^ Effective speed (cash as of November 2021) KDDI
- ^ iOS --Effective speed (cache as of November 2021) KDDI
- ^ a b "Effective Speed Survey by Ministry of Internal Affairs and Communications" Measurement method / measurement result (cash as of November 2021) Softbank
- ^ What is TDD? Koto bank
- ^ LTE-Advanced (3GPP Rel.12) Technology Introduction White Paper p.42 Rohde & Schwartz
- ^ a b Setting off the 5G Advanced evolution Qualcomm
- ^ Full Duplex DOCSIS Technology: Raising the Ante with Symmetric Gigabit Service CableLabs February 2016, 2
- ^ Advanced carrier aggregation and Dual Connectivity technology for even higher speeds and larger capacities p.37 NTT DoCoMo 2015
- ^ "Design and Optimization for 5G Wireless Communications" p.320 Haesik Kim June 2020, 6 ISBN-978 1119494553
- ^ "LTE for UMTS: Evolution to LTE-Advanced" p.466 Harri Holma, Antti Toskala March 2011, 3 ISBN-978 0470660003
- ^ a b TCP and congestion control learned from the basics …… Congestion control algorithms that you want to keep in mind Gijutsu-Hyoronsha December 2019, 7
- ^ BBR Control in QUIC and HTTP / 3 LightSpeed 2019
- ^ Overview of ITU-T SG15 Q4 xDSL and G. (mg) fast p.16 Hubert Mariotte 2017
- ^ G.INP Retransmission fawn
- ^ What is OFDM? MathWorks
- ^ A new report shows which mobile carriers score the highest in 5G real-world cloud gaming TechRepublic May 2020, 5
- ^ Current status of IX and new developments-Aiming for sustainable IX- p.13 QTnet July 2021, 7
- ^ Everyone's internet line speed (cache as of May 2022, 5) "Average value of each line type (last 3 months)" on flow
- ^ Mobile --Japan Median Speeds April 2022 Ookla
- ^ Fixed Broadband --Japan Median Speeds April 2022 Ookla
- ^ a b How busy is the access network? IIJ December 2020, 12
- ^ Last-mile delay survey / 2020-04-01 IIJ 2020
- ^ a b c d Changes in the number of contracts for broadband services, etc. [As of the end of June, 3rd year of Reiwa] Ministry of Internal Affairs and Communications
- ^ a b Population based on the basic resident register, demographics and points of the number of households (as of January 1, 1) Ministry of Internal Affairs and Communications
- ^ Satisfied with 4K broadcasting and image quality, but dissatisfied with the lack of programs. A-PAB announces market research results Ongen Publishing April 2021, 04
- ^ a b JANOG49 --Let's talk about QUIC Softbank January 2022, 1
- ^ a b Government broadband concept. By 2005, 4,000 million households will be in a broadband environment.Aim to triple the real number prediction ITmedia July 2001, 10
- ^ Mr. Takeda, Ministry of Internal Affairs and Communications "Utilization of broadband infrastructure is behind" --MBA workshop CNET Japan October 2005, 12
- ^ a b Ministry of Internal Affairs and Communications announces draft guidelines for "Broadband Zero Area Escape Plan" Impress February 2004, 12
- ^ "Task Force on ICT Policy in the Global Era" Working Group on Response to Environmental Changes in Telecommunications Market" (Press Release), Ministry of Internal Affairs and Communications April 2015, 10Browse.
- ^ Next Generation Broadband Strategy 2010-Nationwide Development of Broadband Through Public-Private Partnership- (Summary Version) Ministry of Internal Affairs and Communications August 2006
- ^ The first meeting of the study group on wireless access systems to eliminate broadband blank areas Ministry of Internal Affairs and Communications January 2006, 6
- ^ Holding a research study group to promote broadbandization in disadvantaged areas Ministry of Internal Affairs and Communications January 2007, 7
- ^ What is the Path of Light (Hikari no Michi)? Weblio dictionary
- ^ Hearing on PSTN network migration, NTT presents alternatives for payment / signal monitoring communication Nikkei July 2011, 7
- ^ Outline of ICT-related priority measures of the Ministry of Internal Affairs and Communications in 31 p.11-12 Ministry of Internal Affairs and Communications November 30, 11
- ^ ICT Infrastructure Regional Development Master Plan -Solving Regional Issues Utilizing ICT Infrastructure in the Society 5.0 Era- p.1, p.7 Ministry of Internal Affairs and Communications June 2019, 6
- ^ Study Group on Broadband Infrastructure (1st) Handouts --About Broadband Infrastructure Ministry of Internal Affairs and Communications January 2020, 4
- ^ Secondary correction, optical line maintenance two years ahead of schedule, urgent need for telework and distance learning Sankei Shimbun March 2020, 6
- ^ 5G network, 23% of the population in 9 Kumamoto Nichinichi Shimbun December 2021, 12
- ^ Reference materials for the future image of the digital garden city-state p.22 Digital Agency December 2021, 12
- ^ NTT East and West to provide "FLET'S Hikari" test service up to 10 Mbps Impress February 2000, 12
- ^ "Announcement of quarterly data regarding the number of telecommunications service contracts and market share (FY27 third quarter (end of December))" (Press Release), Ministry of Internal Affairs and Communications, (July 2016, 3) April 2016, 4Browse.
- ^ The number of "FTTH" contracts has increased by 100 million in the last six months, and demand has increased due to telework, etc. Impress February 2020, 12
- ^ With 5G coming, your neighborhood could get 10Gbps cable broadband VentureBeat March 2018, 3
- ^ au Hikari launches "Type G" with 664 Mbps downlink for existing metal telephone lines for condominiums Impress February 2018, 10
- ^ a b What happens to VDSL when ADSL ends?Fear of being left behind by speeding up Nikkei BP July 2019, 6
- ^ Free type change work from VDSL wiring in the condominium to optical wiring-NTT East Japan Impress February 2020, 7
- ^ Internet condominium function Panasonic
- ^ Intensifying competition among condominium ISPs for existing rentals "All-units collective condominium ISP share survey" (end of March 2020) MM Research Institute August 2020, 8
- ^ a b c ICT Infrastructure Regional Expansion Master Plan 3.0 p.3 October 2020, 12
- ^ Summary of evaluation results of the radio wave usage survey for mobile phones and national BWA in Reiwa XNUMX (draft) Ministry of Internal Affairs and Communications August 2022
- ^ Our efforts regarding flexible fibers NTT East / NTT West June 2020, 11
- ^ Study Group on Broadband Infrastructure (XNUMXnd) Explanatory Materials p.4 KDDI May 2020, 5
- ^ Publication of quarterly data on the number of telecommunications service contracts and market share (Reiwa 3rd quarter (end of December)) p.2 Ministry of Internal Affairs and Communications July 2022, 3
- ^ Frequency reorganization action plan (XNUMXnd revised edition of Reiwa XNUMXnd year) p.6 November 2020
- ^ Frequency reorganization action plan (XNUMXnd revised edition of Reiwa XNUMXnd year) p.19 November 2020
- ^ a b c d Evaluation of temporary radio wave usage survey to meet new radio wave usage needs such as 5G in the first year of Reiwa Ministry of Internal Affairs and Communications August 2020
- ^ Wi11, a public wireless LAN service using 2n, starts in Marunouchi, Tokyo Impress February 2009, 4
- ^ Public wireless LAN service for au smartphones "au Wi-Fi SPOT" starts from June 6 ITmedia July 2011, 6
- ^ Public wireless LAN (outing access) Softbank
- ^ Standard outline (STD-T71) Radio Industry Association
- ^ Product Details --Multi Access Concentrator --Business Solution Panasonic
- ^ Long-distance wireless LAN Falcon WAVE Tokyo communication equipment
- ^ a b JRL-849AP / ST Japan Radio
- ^ Embedded wireless LAN JRL-849E Japan Radio
- ^ Stationary wireless LAN JRL-849AP2 series Japan Radio
- ^ 総務省、Wi-Fi 6Eの6GHz帯を認可 Impress February 2022, 9
- ^ a b Region BWA and WiMAX Regional BWA Promotion Council
- ^ 2G service using a part of WiMAX 5+ frequency band will be started sequentially from September 9st UQ Communications April 2022, 4
- ^ UQ、WiMAX 2+周波数帯の5G転用を12月以降に延期 Mynavi December 2022, 8
- ^ WCP, "AXGP" with a maximum downlink speed of 110 Mbps will be operational in November, service will start in February Impress February 2011, 9
- ^ UQ will start "WiMAX 110+" service with a maximum of 2 Mbps at the end of October, initially "no upper limit" Nikkei BP July 2013, 9
- ^ au to provide services with a maximum downlink speed of 370 Mbps Impress February 2016, 5
- ^ Carrier Aggregation (FDD x TDD) Softbank
- ^ a b c The 3rd Study Group on Future Network Infrastructure Advancement of Networks in Cable TV p.4 JCOM June 2017, 3
- ^ Q & A about the new 4K8K satellite broadcast reception system p.14 JEITA 2018
- ^ Latest Trends in DOCSIS-Product Applicability in Japan with International Standardization of DOCSIS 3.1 and 4.0- p.16 Japan Cable Laboratories 2020
- ^ J-COM Kanto provides 160Mbps ultra-high-speed Internet service in Kanto area BCN + R December 2007, 9
- ^ J: COM speeds up Internet connection service "160M course" to 320M and "40M course" to 120M Impress February 2015, 1
- ^ J: COM, digital-analog conversion service will be terminated sequentially from January 2015, 1 Mynavi December 2014, 11
- ^ J: COM NET 1G course (cash as of October 2017, 10) J: COM
- ^ About the start of "J: COM NET 1G course" J: COM October 2017, 10
- ^ Service development unique to JCOM, which develops online / mobile / cable TV --JCOM holds a new service presentation in the fall and winter Impress February 2021, 11
- ^ Current status of networks and efforts for sophistication p.6 J: COM June 2018, 6
- ^ Latest Trends in DOCSIS-Product Applicability in Japan with International Standardization of DOCSIS 3.1 and 4.0- p.11 Japan Cable Laboratories 2020
- ^ 29 activity report of federation committees, subcommittees, organizations, etc. p.6 Japan Cable and Telecommunications Association
- ^ Japan Cable and Telecommunications Association 29 Business Report p.5 Japan Cable and Telecommunications Association
- ^ Outline of Cable TV Network Optical Promotion Project Attachment 1 Ministry of Internal Affairs and Communications
- ^ Disaster resistance enhancement project by using cable TV to establish "new daily life" p.1 Ministry of Internal Affairs and Communications
- ^ Emergency measures for cable TV operators to switch to optical cables, etc. Ministry of Internal Affairs and Communications
- ^ Emergency measures business open call for participants regarding optical cable conversion of cable TV operators Ministry of Internal Affairs and Communications
- ^ About Tottori-shi ultra-high-speed information and communication infrastructure maintenance business Tottori City April 2021, 4
- ^ Survive in the high-speed two-way 5G era with JCOM and CATV and invest 3000 billion yen Nihon Keizai Shimbun January 2019, 2
- ^ Started offering "J: COM NET Hikari 10G / 10G Course" with a maximum of 5Gbps up and down Impress February 2020, 2
- ^ Current status of cable TV Reiwa September 3rd edition p.4, p.6 Ministry of Internal Affairs and Communications 2021
- ^ Publication of quarterly data on the number of telecommunications service contracts and market share (Reiwa 3rd quarter (end of December)) p.11 Ministry of Internal Affairs and Communications July 2022, 3
- ^ Opinions and ideas for "Study Group Final Summary on Broadband Infrastructure [Draft]" [Draft] p.35-36 Ministry of Internal Affairs and Communications 2022
- ^ Does coaxial cable exceed "light"? Mechanism of "c.LINK" ITmedia July 2004, 6
- ^ J: COM settlement, "J: COM NET Hikari" official service started. HDD-equipped STB will also be introduced Impress February 2005, 10
- ^ The future of cable 4K pioneered by Japan Cable Laboratories --8th Advancement of access lines and home networks for 4K services p.36 Japan Cable Laboratories 2015
- ^ @Home Network Starts At Home Japan with J-COM RBB TODAY October 1999, 4
- ^ At Home Japan aims to have 27 subscribers ITmedia July 2001, 2
- ^ J-COM, CATV Speed up Internet downlink to 2Mbps ASCII September 2001, 6
- ^ J-COM Broadband speeds up "J-COM Net" to 8Mbps downlink / 2Mbps uplink ASCII September 2001, 12
- ^ Internet White Paper 2003 --2-1 Communication Lines and ISPs p.49 Internet Association July 2003, 7 ISBN-978 4844318019
- ^ a b "Yahoo! BB 12M" launched commercial service Impress February 2002, 8
- ^ a b c 8M Cable Internet is not losing speed to 12M ADSL-J-COM ITmedia July 2003, 2
- ^ a b CATV Internet with 30 megabytes of J-COM. Tokyo in September, nationwide by January 9 Nikkei BP July 2003, 7
- ^ "Study Group on Network Neutrality" 4th Jupiter Telecom Explanatory Material p.9 Jupiter Telecommunications December 2018, 12
- ^ JCOM adopts Motorola's "DOCSIS 3.0" compliant system Nikkei BP July 2008, 4
- ^ "J: COM NET" 160M course is accelerated to 320Mbps with the charge unchanged, starting from Kansai Nikkei BP July 2015, 1
- ^ About the speed increase completed in the past J: COM
- ^ About speed improvement (acceleration) of J: COM NET line J: COM
- ^ Introducing ADSL connection service up to 8 Mbit / s Nikkei BP July 2001, 8
- ^ 37th: Asking operators about the latest trends in 12Mbps ADSL-ACCA Networks- Impress February 2002, 12
- ^ Ymobile launches "ADSL Plus" with a maximum of 12 Mbps in October ITmedia July 2002, 6
- ^ ADSL Nikkei BP
- ^ "Announcement of quarterly data regarding the number of telecommunications service contracts and market share (FY29 third quarter (end of December))" (Press Release), Ministry of Internal Affairs and Communications, (July 2017, 9) April 2017, 9Browse.
- ^ "About the end of new application for "FLET'S ADSL"" (Press Release), NTT East, (July 2015, 7) April 2015, 10Browse.
- ^ "About the end of new application for "FLET'S ADSL"" (Press Release), NTT West, (September 2015, 7) April 2015, 10Browse.
- ^ "Regarding the end of "FLET'S ADSL" service in the "FLET'S Hikari" service area" (Press Release), NTT East, (July 2017, 11) April 2017, 11Browse.
- ^ "Regarding the end of "FLET'S ADSL" service in the "FLET'S Hikari" service area" (Press Release), NTT West, (September 2017, 11) April 2017, 11Browse.
- ^ Speednet will start this service from May ── 5 Mbps for wireless, 1.5 Mbps for wired ITmedia July 2001, 3
- ^ a b Monthly Telecommunications Interview September 2002 Speednet President: Hiroshi Wada The area has been improved and the number of subscribers has increased rapidly. Rick Telecom 2002
- ^ a b Speednet wireless access service ends at the end of May 2006 Impress February 2005, 11
- ^ NTT Com launches commercial service of wireless LAN service "hotspot" -IEEE802.11a / b dual support ASCII September 2002, 4
- ^ Softbank announces wireless Internet connection "Yahoo! BB Mobile" by IEEE802.11b RBB TODAY October 2002, 4
- ^ NTT DoCoMo launches public wireless LAN service "Mzone" ASCII September 2002, 6
- ^ Japan Telecom launches public wireless LAN service "Mobile Point" CNET Japan October 2004, 4
- ^ Public wireless LAN service for providers "Mobile Point" Japan Telecom
- ^ About the transfer of Speednet's Internet business to TEPCO-Providing a new service that integrates optical fiber and wireless to 23 million households in the 1 wards of Tokyo and 3 metropolitan area and 600 prefectures- TEPCO March 2003, 3
- ^ TEPCO launches "5GHz wireless type" connection service for apartments at "TEPCO Hikari" ASCII September 2003, 11
- ^ Regarding the termination of some services (formerly "TEPCO Hikari" service) in the optical fiber service "Hikari one" <Attachment> KDDI
- ^ What you can and cannot expect to open up outdoor use of 5GHz band wireless access Impress February 2002, 7
- ^ Efforts of the Ministry of Internal Affairs and Communications ② p.6 Ministry of Internal Affairs and Communications
- ^ Wi-Fi security in transition Network World July 2010, 7
- ^ NTT Com reviews the lineup of public wireless LAN services and integrates them into "OCN hotspots" Nikkei BP July 2012, 6
- ^ About review of OCN hotspot service area OCN January 2013, 1
- ^ Notice of end of provision of SSID "docomo" due to the abolition of WEP method of docomo Wi-Fi NTT DoCoMo May 2013, 9
- ^ Yahoo! BB Mobile Launched roaming service in partnership with 6 domestic and overseas operators-Established a mobile zone with a maximum of 54 Mbps standard and expanded to 5,000 bases within the fiscal year- Yahoo Japan March 2004, 6
- ^ About the start of provision of "FLET'S Spot" and the provision of a new menu of "M FLET'S" NTT East November 2004, 11
- ^ Livedoor public wireless LAN "livedoor Wireless" haste report Impress February 2005, 8
- ^ livedoor Wireless, service ends on April 4 RBB TODAY October 2013, 1
- ^ "NTT's 10 Years: 1985 → 1995 Material Edition" p.110 NTT Learning Systems Edition July 1996
- ^ "Modern Product Dictionary New Product Edition" Toyo Keizai Inc. October 1986, 10 ISBN-978 4492010365
- ^ 26GHz subscriber radio for 1SS-D26 system-Industrial history database National Science Museum
- ^ "1990s Telecom Strategy-Vision for Advanced Telecommunications" Ministry of Posts and Telecommunications Telecommunications Council October 1987, 10 ISBN-978 4478240403
- ^ a b Information and Communication Council Information and Communication Technology Subcommittee Land Radio Communication Committee Report p.5 Ministry of Internal Affairs and Communications
- ^ a b NTT East ends new acceptance of B FLET'S "Wireless Access Type" Impress February 2009, 3
- ^ a b NTT West's "B FLET'S Wireless Family Type" service ends at the end of November 2017 Impress February 2016, 3
- ^ a b Outline of preliminary survey for frequency transition of 26GHz band FWA Ministry of Internal Affairs and Communications 2022
- ^ Summary of survey results regarding the use of 5th generation mobile communication systems Ministry of Internal Affairs and Communications January 2018, 9
- ^ 2021 version of "Frequency Reorganization Action Plan", aiming to secure a bandwidth of about 2025 GHz by the end of 16 Impress February 2021, 11
- ^ Frequency reorganization action plan (Reiwa 3rd year version) p.10 Ministry of Internal Affairs and Communications 2021
- ^ au lifts ban on smartphone tethering-WiMAX compatible Android terminal "HTC EVO WiMAX ISW11HT" ITmedia July 2011, 2
- ^ Developed 2011 models for the 24 summer model and released some models NTT DoCoMo May 2011, 5
- ^ iPhone 5 is about to be released Softbank renews its appeal with five "let's do it" ITmedia July 2012, 9
- ^ Wireless City Planning ends "XGP" in January 2012-Focusing on AXGP in the future ITmedia July 2011, 12
- ^ UQ's old WiMAX service ended on March 3st, 31 years since the start of 2009 ASCII September 2020, 4
- ^ Optical fiber maintenance status at the end of Reiwa 2 Ministry of Internal Affairs and Communications
- ^ Optical fiber maintenance status at the end of Reiwa 2 (municipalities) Ministry of Internal Affairs and Communications
- ^ Optical line, provided sequentially from March such as Aki Nada XNUMX islands to almost the entire Kure city Chugoku Shimbun January 2022, 2
- ^ About the current situation of remote islands and examples of efforts p.8 Ministry of Land, Infrastructure, Transport and Tourism April 2022
- ^ About the situation of dead zones where mobile phones cannot be used (as of the end of Reiwa 2) Ministry of Internal Affairs and Communications
- ^ Mobile phones can be used in 6 tunnels on the Yamagata Shinkansen Areas have been completed on Shinkansen nationwide ITmedia July 2020, 11
- ^ a b ICT Infrastructure Regional Deployment Master Plan Progress Report Ministry of Internal Affairs and Communications January 2020, 6
- ^ DoCoMo maps the communicable areas of Japan's XNUMX famous mountains ITmedia July 2016, 7
- ^ What is the mechanism for connecting smartphones on mountain trails? Introducing XNUMX famous mountains to which au is connected KDDI July 2019, 7
- ^ Use DoCoMo and au radio waves at a low price!Why dual SIM is recommended for mountain smartphones Mountain and valley company April 2022, 1
- ^ Information and communication environment improvement in rural areas p.20 Ministry of Agriculture, Forestry and Fisheries January 2022, 1
- ^ It is necessary to improve the radio wave environment in medical institutions, and the radio wave condition is poor in corridors, stairs, and underground areas. GemMed January 2020, 1
- ^ Can the iPhone be used on the upper floors of a tower apartment? --Why the iPhone can't be heard anymore? Mynavi December 2013, 1
- ^ Infrastructure sharing market entering takeoff period with full-scale 5G deployment Impress February 2022, 2
- ^ The total number of JTOWER indoor infrastructure sharing solutions introduced in Japan has reached 200 (total floor area: over 1,000 million mXNUMX). JTOWER October 2020, 10
- ^ Aiming to "connect" even in the sea NTT DoCoMo
- ^ "1.2.1. OECD Fixed broadband subscriptions per 100 inhabitants, by technology, December 2020”. OECD. April 2021, 11Browse.
- Narrow band
- Last one mile
- best effort
- Information gap
- data communication
- Satellite internet access