Portal field news

Portal field news

in ,

📱 | TV wireless TV tuner anywhere in the house with your smartphone or PC


TV wireless TV tuner anywhere in the house with your smartphone or PC

If you write the contents roughly
If you add this unit to your home Internet environment and connect it to the antenna line, you can watch TV programs using your smartphone / tablet or PC in a place where the wireless LAN in your home is connected.

Pixela (Osaka City), which handles digital devices, is a TV tuner brand for personal computers and smartphones. → Continue reading

 J-CAST News

Wikipedia related words

If there is no explanation, there is no corresponding item on Wikipedia.

無線 LAN

無線 LANWhat is (Musen orchid)?Wireless communicationIs built usingLAN.Wireless LAN (Wireless LAN, WaveLAN[1]) Or abbreviated itWifiAlso called.There are various wireless LAN communication methods, but as a well-known wireless LAN standardIEEE 802.11There,Wi-Fi(Wi-Fi) is a registered trademark for wireless LANs that use that standard.


Before the spread of wireless LANIrDACompliant with the standardInfrared communicationIs the main means of wireless communication,laptop,Mobile phone, IC card typePublic phoneIt was installed in.After that, IEEE 802.11 was standardized, and from around 1998, it was commercialized as a wireless LAN device based on the standard being formulated by each manufacturer.However, it was not widely used due to problems such as low speed of about 2 Mbps, high price, and inability to connect to each other if different manufacturers.

In IEEE 802.11b, the communication speed was planned to be improved to 11 Mbps, but at that time the price of IEEE 802.11 equipment was high, and the Home RF standard promoted by Intel was considered to be the favorite of home wireless LAN. Ta[2]..However, in July 802.11, just before the official standardization of IEEE 1999b, Apple Computer (currently: Apple)ButAirPort(The name in Japan is AirPort) announced.This has an impact on the market at a low price of $ 299 for access points and $ 99 for cards.[3][4], In JapanMelco(Current: Buffalo)[5]Following each company, IEEE 802.11b standard equipment has become widespread.

2009 year 9 month,IEEE(Institute of Electrical and Electronics Engineers) officially formulated IEEE 802.11n (11n).


When multiple wireless LAN access points are installed, the function that allows continuous communication even if you move away from the connected access point and move to another access point is available.roaming".To use the roaming function, the access point must support the roaming function.

Various methods

IEEE 802.11 series

IEEE 802.15 series

Incidentally,IEEE 802.15SeriesWireless PAN (WPAN: Wireless Personal Area Network) May be classified.


Since wireless LAN communicates by radio waves, there is a risk that the communication contents will be intercepted by a third party.Therefore, security measures are required between the wireless LAN access point and the communicating device.For example, there is a method of limiting computers that can communicate using a password called a network key to only computers that know the network key.

Security technologies in encrypted communication mainly include WEP, WPA, WPA2, and IEEE 802.11i.In addition to the purpose of limiting communication devices by network keys, these encrypted communications also have the purpose of preventing the interception of communication contents by a third party by encrypting the communication contents.

In recent years, encryption decryption technology has advanced, and there is a paper that WEP can decrypt in 10 seconds.[6]. Also,MAC addressThe method of limiting the computers that can communicate with each other is not a strong security measure because it is technically possible to spoof the MAC address.

Information Processing Promotion OrganizationAccording to the authentication method for home useWPA2-PSK, As an encryption methodBEA(CCMP) Is selected and the shared key of sufficient strength (uppercase (A --Z), lowercase (a --z), number (0-9), symbol (!, $,%, \, Etc.) is included 20 You should use more than a letter)[7].

In Japan,crackingIf you illegally break into or attempt a password-protected network using a method such asAct on Prohibition of Unauthorized AccessMay conflict with.

However, there is no criminal problem with the act of simply using a wireless LAN for which no password has been set (free riding).AttorneyHideo OguraAccording to the report, such free riding does not correspond to an unauthorized access act and is not charged with theft, but if it uses a band that interferes with the original user's use, it is a civil pursuit. May receive[8]And

Various functions of wireless LAN

Infrastructure mode, ad hoc mode


SSID (Service Set ID) ・ ESSID (Extended SSID)
ID for grouping wireless LAN connections.Also used for authentication.Up to 32 alphanumeric characters can be set.Normally, you cannot connect unless the settings of the access point and client match.It is possible to set so that you can connect without matching,Free spotIt is not recommended from the viewpoint of security except when providing public free connection services such as.

Communication protocol and encryption method

WEP (Wired Equivalent Privacy)
Early standard for wireless LAN.Security vulnerabilities have been pointed out, and the use of the WEP method is not recommended.[9].The WEP password can be decrypted in about 10 seconds.[10],AirSnortSince cracking software such as is on the market, it can be easily hijacked.
WPA (Wi-Fi Protected Access)
Prior to the formulation of IEEE 802.11i to improve WEP vulnerabilitiesWi-Fi AllianceWas enacted by.TKIP for encryptionTemporal Key Integrity Protocol) Is used, but this is in WEPRC4It is an attempt to avoid known attacks as much as possible by adding a function that mixes the key and the initial vector to the method.However, in reality, many of the same attacks as in WEP will work (see details).English version of TKIP articleSee).
WPA2 (Wi-Fi Protected Access 2)
Enhanced security version of WPA. With the formulation of IEEE 802.11i, it was enacted to incorporate it.As an encryption methodAuthenticated encryption OfBEA-CCMでMPDUAnd protect its headerCCMPThe method is adopted.
WPA3 (Wi-Fi Protected Access 3)
Serious vulnerability regarding WPA2,KRACK A security standard established in June 2017 following the report of (Key Re-installation Attack) in October 10. Vulnerability was also reported in WPA2018 in April 6[11], The cat-and-mouse game continues.

PSK mode and EAP mode

WPA / WPA2 / WPA3 has two modes, PSK mode and EAP mode.

PSK mode (Pre-Shared Key) isPersonal modeAlso called, a password is set in advance on the access point side, and the connection is started by entering the password on the terminal side.The key used for communication is from the passwordPBKDF2Algorithm (Key derivation function) Is used for calculation.

on the other handEAP mode TheEnterprise modeAlso calledRADIUSUsing an authentication serverEAP By authentication of (Extensible Authentication Protocol)PPPsConnecting.The details are standardized to IEEE 802.1x.


Since wireless LAN is more complicated to set up than wired LAN, there are the following standards and systems.Depending on the model, it may be necessary to set manually.

WPS (WiFi Setup)
A standard that makes it easy for beginners to set up WPA.Wi-Fi AllianceIt is formulated by and can be used by any manufacturer.There is a security problem in the standard,PINIf you use authentication, the PIN will beBrute force attackCan be done[12][13][14]Therefore, if authentication fails several times, it is necessary to use a model that is set to lock authentication, or to protect it by disabling WPS after setting the PIN on the user side.[14].
AirStation One-Touch Secure System(AOSS)
BuffaloIs on saleAirStationThe setting system introduced in.
Easy wireless start
NEC Access TechnicaCo., Ltd. (currentlyNEC Platforms) Developed setting system.

Original expansion

Some manufacturers have technologies that have their own improvements while ensuring connectivity with IEEE 802.11a / b / g.There are "SuperAG", "SuperG", "Frame Burst", "Frame Burst EX", etc. as high-speed technology (compression, protocol optimization, etc.), and "XR (eXtended Range)" as reach area expansion technology (SuperAG, SuperG). , XRRiceQualcomm Atheros Of商標).Since these are manufacturers' own extensions, there is no effect unless the master and slave units are made by the same manufacturer and both are compatible.These appearances were around the time when 54a and 802.11g, which had a maximum communication speed of 11 Mbps, were the mainstream, but they have not been seen much since 802.11n, which has significantly improved communication speed, became widespread.

Mesh wireless LAN

Mesh type wireless LANAlso called[15] [16].Mesh networkIs applied to wireless LAN, and there are multiplesatelliteAre interconnectednetworkMake up.

Public wireless LAN

A service that provides the public with a connection to an access point, thereby providing a means of connecting to the Internet.Public wireless LANSay.Hotspots for public wifiFREESPOTand so on.

Wideband wireless LAN

5 GHz bandWireless accessシステムAlso called. 250mW high output wireless LAN (IEEE 802.11j), And the transmission distance is several kilometers[19]..The dedicated frequency is 4.9 to 5 GHz (184, 188, 192, 196 channels).The maximum communication speed is 54 Mbps (best effort).When using itRadio station licenseNeed to get[20].

Vast construction site / farm / factory[21]On-site LAN such as, or LAN line connecting remote facilities[22][23], Municipality[24][25]·Residents' association[26]Self-employed wireless IP communication such as, wireless internet line provided in areas where it is difficult to draw ADSL / optical line "Skynet V"Ginoza VillageBroadband service Ginoza BB "[27]Used in etc.

Use in companies, etc.

With the widespread use of wireless LAN, wireless LAN access points have become more sophisticated and are increasingly used in various situations.However, due to the characteristics of wireless, it is necessary to install a large number of devices when configuring a large-scale network such as for enterprises, so problems such as management / maintenance and fault tolerance occur with high-performance single devices for home use. Sometimes.Therefore wirelessLAN switchCentralized management is performed using (wireless LAN controller), and a wireless LAN access point with the simplest design (thin access point) may be selected.

Laws and regulations of each country


Radio Act

JapanIn 1992 (4)Radio ActSo-called decreeLow power radio station OfLow power data communication system OfRadio stationAnd technical standards were set.ThislicenseIs unnecessaryCertification of conformity with technical standardsWas decided to be required.In addition, what connects to the telecommunication lineTelecommunications Business LawOrdinanceCertification of conformity with technical standardsAlso required.

The items that need to be displayed and the contents related to wireless LAN are as follows.  

TypesSymbol, typeRemarks
Technique markCWith lightning insidePostal CodeArrange.Display starts when technical standards are applied

Mark revision in April 1995 (Heisei 7)
As a general rule, diameter 5 mm or more

Certification of conformity with technical standards2400 to 2483.5MHzWWWhen the technical standard was first applied, it was placed in the first or second letter of the number in GZ.

From October 1999 (Heisei 11), 10 to 2400MHz became NY.
From March 2000 (Heisei 12), the 3 GHz band was added and it was designated as WY.
It was placed in the 2001rd to 13th letters of the number from October 10 (Heisei 3).
It was placed in the 2003rd to 15th letters of the number from October 7 (Heisei 4).
From May 2005 (Heisei 17), the 5GHz band and 5.2GHz band were designated as WY.
From March 2007 (Heisei 19), the 3GHz band was added and it was designated as TW.
From June of the same year, NY was designated as WW, WY as XW, and TW as YW.
From December 2011 (Heisei 23) by construction design certification
(The fourth letter of the number ishyphen(-)) Does not require symbol display.

2471 to 2497MHzGZ
5.2, 5.3GHz bandXW
5.6 GHz bandYW
Note: The proof is valid even if the mark and number structure is the same as before.

Do not use in Japan without the technical suitability mark..In addition, the technical standardsantennaExcept for the system, there is a special saying that it cannot be opened easily.screwEtc. are used, so the user must not disassemble it not only for modification but also for maintenance and repair.Even if it is for domestic use, if it is modified, the technical standard conformity certification will be invalid.Illegal radio stationBecomes

ISM bandHarmful from usinginterferenceMust be tolerated[28]..For the most popular 2.4GHz band equipment, it is in operationmicrowaveIn the vicinity of, communication will be significantly affected or communication will be impossible.Also,VICS (ETC) ・ For general useRFID-Amateur radio stationEquipment, etc.Wireless station license・ Operate after receiving radio station registrationRadio stationFor harmful interference fromThere is no right to object or exclude, and conversely, if requested to discontinue use, the user must obey..

Furthermore, as a low-power wireless station equivalent to wireless LAN, RFID for low power,2.4GHz band digital cordless phone, Model airplaneRadio control,Multicopter,BluetoothFor these, the one used first has priority, but in reality, interference cannot be completely avoided.Multiple devices on different networksaccess pointWhen the channels overlap due tothroughputIt is affected by the decline.

In 2010 (Heisei 22), it was said that it was selling high-output wireless LAN equipment that exceeded the provisions of the Radio Law.Osaka-Nihonbashi OfElectronics storeHas been caught and the owner has been arrested[29].

Wireless LAN in amateur radio

August 2009 (Heisei 21),Amateur radio stationJF1DQI can operate IEEE 5.6b / g wireless LAN as an amateur business in 10.1GHz band, 24GHz band, 802.11GHz bandWireless station licenseWas given.For the equipment, use a commercially available USB wireless LAN adapter with an external antenna terminal (2000 yen or less), and use that antenna terminal.TransverterIt is possible to operate in the 5.6GHz band, 10.1GHz band, and 24GHz band by connecting (device that performs frequency conversion).

Amateur radioThen,JargonNo use or confidential radio equipment is allowed[30][31]Therefore, it was required to operate a radio station without setting WEP / WPA, which is an encryption technology.Frequency bands that can be used by amateur radioThere is also a 2.4GHz band, but operation in this frequency band was not permitted because of the commonly used "possible misconnection with wireless LAN".We are aiming to experiment with long-distance and high-speed data communication in microwaves.In addition to this station, several stations in the Greater Tokyo area are preparing to apply for a radio station license.[32].


In the United StatesFederal Communications Commission (FCC) manages the wireless LAN network[33].

In the United States, there is a movement to regulate the construction of broadband networks including wireless LAN by local governments by state law, as telecommunications carriers have claimed that it is putting pressure on the private sector.[33].. As of February 2014, 2 states have imposed restrictions on broadband service provision.[33].


[How to use footnotes]
  1. ^ WaveLAN
  2. ^ "Home Networking's Bitter Brawl". Wired (September 2000, 9). 2017/8/22Browse.
  3. ^ IEEE802.11b Next Generation Wireless LAN Standard webBCN
  4. ^ Wireless LAN-The Road to Its Glory (Part XNUMX) ITmedia
  5. ^ New release of 11Mbit / s wireless LAN "AirStation" BUFFALO
  6. ^ "WEP can be deciphered in 10 seconds" announced by a group of Kobe University and Hiroshima University Impress Watch February 2008, 10
  7. ^ Precautions regarding wireless LAN security in ordinary households Information Processing Promotion Organization
  8. ^ Is it illegal to connect to the Internet via wireless LAN radio waves from my neighbor? ITpro Nikkei NETWORK August 2008 issue p.8
  9. ^ ""Why Wi-Fi security is not good with WEP"”. Canon IT Solutions Malware Information Bureau (November 2015, 11). 2016/9/28Browse.
  10. ^ ""WEP can be deciphered in 10 seconds" announced by a group of Kobe University and Hiroshima University”. Internet Watch (October 2008, 10). 2016/9/28Browse.
  11. ^ Tomohito Isoya (April 2019, 4). “Vulnerability in the new Wi-Fi security standard "WPA3", discovered less than a year after its appearance”. Internet Watch. 2019/10/28Browse.
  12. ^ Walker-Morgan, Dj (December 2011, 12). “Wi-Fi Protected Setup made easier to brute force”. . オ リ ジ ナ ルArchived as of October 2012, 5.. https://web.archive.org/web/20120502071608/http://www.h-online.com/open/news/item/Wi-Fi-Protected-Setup-made-easier-to-brute-force-Update-1401822.html 2011/12/31Browse. 
  13. ^ "Wi-Fi Security – The Rise and Fall of WPS". Netstumbler.com (September 2013, 1). 2013/12/17Browse.
  14. ^ a b ""WPS" that simplifies wireless LAN settings, vulnerable to PIN method specifications- @ IT”(May 2012, 1). 2016/5/7Browse.
  15. ^ ""Super easy" wireless LAN with mesh Wi-Fi”. Businessnetwork.jp (August 2019, 8). 2019/12/25Browse.
  16. ^ "Recommended mesh Wi-Fi model that strengthens radio waves”. PREMOA MAGAZINE (November 2019, 11). 2019/12/25Browse.
  17. ^ "Betsukai, Nakashibetsu district"High-speed wireless communication service" SKYNET V "" Orrence Co., Ltd.
  18. ^ 26 Coastal Area Seawater Warming Gas Continuous Monitoring Device / System Element Technology Study Subsidy Project ReportMarch 2015, Engineering Association of Japan, Document 3
  19. ^ However, the commercial service Skynet V can reach up to about 15km.[17], Nippon Denki Kogyo has a track record of communicating at 30 Mbps over 7 km.[18].
  20. ^ "5GHz band wireless access system"Ministry of Internal Affairs and Communications Radio Wave Usage Homepage" Ministry of Internal Affairs and Communications
  21. ^ "Introduction case ZEON CORPORATION"Fujitsu Network Solutions" Fujitsu Network Solutions
  22. ^ "Solution case study Wireless data communication between head office and branch offices"DENGYO Nippon Electric Works Co., Ltd." Nippon Electric Works Co., Ltd.
  23. ^ "Solution case study Broadcast video / FM broadcasting station temporary transmission line"DENGYO Nippon Electric Works Co., Ltd." Nippon Electric Works Co., Ltd.
  24. ^ "Introduction case Tadami Town, Fukushima Prefecture"Fujitsu Network Solutions" Fujitsu Network Solutions
  25. ^ "Onna village long-distance wireless LAN construction"Riuden Co., Ltd." Riuden Co., Ltd.
  26. ^ "Next-generation wireless network system Proposal of 5GHz band wireless access system"Toa Toa Corp." February 2013, Toa Corp., page 2
  27. ^ "Okinawa Prefecture Ginoza Village Area Limited Broadband Service"Ginoza Village" Ginoza Village, Kunigami District, Okinawa Prefecture
  28. ^ "Footnote of Ministry of Internal Affairs and Communications Notification Frequency Allocation Plan J37”. Ministry of Internal Affairs and Communications. 20201118Browse.
  29. ^ "For free online" and illegal wireless LAN sales to arrest vendors on suspicion "Osaka Prefectural Police Department Sankei Shimbun September 2010, 9
  30. ^ Radio Law Article 58 No jargon shall be used for communication conducted by radio stations such as experiments and amateur radio stations.
  31. ^ Radio equipment regulationsArticle 18-2 The transmitter of an amateur station shall not have the function of giving confidentiality to communication.
  32. ^ "Microwave World" Satoshi Kumano "CQ ham radio』May 2009 issue,CQ publishing
  33. ^ a b c Survey report on the status of public wireless LAN maintenance in other countries Foundation for MultiMedia Communications

Related item

外部 リンク


Back to Top