Portal field news

Portal field news


🌏 | Boeing and Airbus are concerned about the safety of 5G


Boeing and Airbus Concern 5G Safety Is It Bad for Aviation Equipment?

If you write the contents roughly
Meanwhile, the wireless communications industry group CTIA has criticized 5G as a secure technology, distorting the facts by mischievously frightening the aviation industry.

Boeing and Airbus management, a major aircraft manufacturer, told the U.S. government on the 21st that they would use the 5th generation mobile communication system (... → Continue reading


From the news, readings, and feature articles of BBC journalists who interview in about 100 countries around the world, we select and deliver topics that are meaningful to Japanese users who are knowledgeable.

Wikipedia related words

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

Industry group CTIA

Wireless communication

Wireless communication(Musentsushin,British: wireless communication) Is mainlyRadio waveDo usingTelecommunicationsIs that[1]..Often shortened to "wirelessIs called.In contrast to wireless communication that uses radio waves, communication that uses cables as a transmission line isWired communicationCall.


Radio Law Enforcement RegulationsIn, wireless communication is "all kinds of radio waves.symbol,signal,文言,image,acousticOr情报 OfSEND, Launch orReceiveIs said to be "(Radio ActEnforcement Regulations Article 2, Paragraph 1, Item 15).About how radio waves are transmittedRadio wave propagationSee also

Wireless communication has the following features.

  • There is no need to lay a line as a transmission line.
  • Although it depends on the frequency used and the transmission output, it is possible to provide services in a very wide range and communicate with a large number of nodes.It is also suitable for broadcasting.
  • It may be affected by changes in transmission line conditions (such as changes in weather).
  • Others that generate radio waves, etc. (Source of interferenceThat.(I.e.Other than the earth includingCelestial body,Electronics,Prime moverSuch. ) May be affected.
  • Information transmitted is relatively easy for a third partyInterceptionit can.To prevent this, it is difficult for a third party to restore the information.modulationUse the method or the contentencryptionMeans such as


The applications of wireless communication are as follows.

However, on TVリ モ コ ンWireless communication may include optical communication such as, etc. (However, especially for optical communication, "Optical wireless communicationIs often called).Also, rarely, but in a broader senseSound waveMay also be included in "wireless communication".




  • 1900:FessendenSucceeded in an experiment to put voice on radio waves
  • 1906: Fessenden,Radio broadcastSuccessful experiment
  • 1912:Uichi Torigata・ Eitaro Yokoyama, Seigo Kitamura, TYK ceremonyWireless phoneInvented. After a practical test in Toba, Mie Prefecture from December 1914, 12, it was put into practical use on April 16, 1916.
  • 1919: Marconi succeeds in developing a 20 watt vacuum tube that operates at 200 MHz shortwave.CaernarfonHoly headSucceeded in wireless telephone experiment at 32km[4]
  • 1920:Frank Conrad, The world's first commercial radio station KDKA in the United StatesPittsburghOpened at[5].
  • 1921: Marconi succeeds in cross-North Sea call (UK-Netherlands) with simultaneous radiotelephone using two shortwave 3MHz band[6]
  • 1923: AT & T and UK Postal Service GPO begin testing transatlantic radiotelephones with single-sideband SSB[7].. Main business started on January 1927, 1[8].
  • (Same year): Frank Conrad succeeds in broadcasting the program of radio station KDKA to the BBC in the UK across the Atlantic Ocean on the 3MHz shortwave experimental station 8XS.[9].
  • 1924: Marconi successfully receives 2MHz shortwave radiotelephone from Poldhu 3YT station in Australia[10]
  • 1931: ITT (International Telephone and Telegraph Corporation) laboratory in the UK and MT (Le Matériel Téléphonique) laboratory in France succeed in demonstrating across the Strait of Dover with an ultra-shortwave 1.67 GHz radiotelephone.[11].. Official operation started in 1934[12].
  • 1933: Marconi begins operation of simultaneous radiotelephone in the 500MHz band connecting the Vatican Palace and the Pope Gandolfo Palace.This was the world's first practical UHF band line.[13].

Comparison with wired communication

Mobile communicationIf you doWireless communicationHowever, if you are trying to communicate between fixed points, both wired and wireless are options.To briefly describe the cost required in each case, in the case of wired communication, the cost is accumulated according to the length of the line, but in the case of wireless communication, the cost is accumulated according to the number of transmission / reception equipment. Therefore, there is an aspect that wireless communication is cheaper in long-distance communication.

On the other hand, in the case of wired communicationCircuit switchingForswitchIn many cases, multiple communications are established using (within the same communication network), whereas in the case of wireless communications, individual communications are established.Transmitteras well as the Receiving machineIn frequency andmodulationA method of establishing multiple communications is taken by distinguishing by, and the number exceeds the number of exchanges in the case of wired communications.Although it is very difficult to compare the prices of exchanges, transmitters and receivers (or the prices including terminals required in each case) in general terms,1990 eraIn the price situation until aroundTelecommunications carrierIt is said that wired communication was inexpensive when the density of the starting point and ending point of communication (sometimes referred to as an access point to the line) was high, assuming that the service is provided.

Phone example

As an example of this, the network used to have a hierarchical structure.TelIs listed.Wired communication was used to connect households (access points) in the city to exchanges, but wireless communication was often used for long-distance communication beyond the exchange to exchanges in other prefectures.This is because the communication network connecting the exchanges is relatively long-distance, the density of access points is low, and the communication network is discrete. Therefore, wireless communication was initially superior in terms of price. ..

However, since the 1990s, the frequency has become tight andOptical fiberDue to the fact that large-capacity communication has become very cheap, long-distance communication of telephones has been replaced by wired communication by optical fiber.Denden Public Corporation(NowNTT) From the towers in many branchesparabolic antennaIs disappearing, and this is why another antenna for mobile communication is being installed.

Military world

In the military world, you can't wait for a cable to be laid on the battlefield, so wireless is important.Wired communication remains, but is limited, due to the danger of being intercepted by the enemy and its strength against jamming.Wired communicationFrench-French warIt is well known that it contributed to the victory or defeat of.By the time of World War I, it became possible to instruct artillery on shooting targets by communication, and practical long range shooting became possible.By the time of World War II, radio became widespread, allowing troops and vehicles to move and organically combine.Even today, the impact of the development of communication technology on the military continues to increase.RMAIt has become the core of the innovation called.

Information transmission in an emergency

Another important merit of wireless communication is information transmission in an emergency.Once in JapanGreat Kanto EarthquakeAt that time, with a wired phone or overseasSubmarine cableFacilities such as these were destroyed, communication was hindered, and an isolated and unsupported situation occurred, but first by radio from a ship in Tokyo BayNavy wireless telegraph station Funabashi transmitting stationTo, and more (only the antenna towerMemories & Haramachi Radio TowerIt was transmitted to the United States and abroad through (remaining as) and was able to obtain world relief.This is the first case where wireless was used during a large-scale disaster in Japan.[14][15][16][17][18].


[How to use footnotes]
  1. ^ Japanese Language Dictionary, Britannica International Encyclopedia Small Item Encyclopedia, Digital Daijisen, World Encyclopedia XNUMXnd Edition, Encyclopedia Nipponica (Nipponica), Selected Edition.What is wireless communication?”(Japanese). Koto bank. 2021/2/5Browse.
  2. ^ Communications engineer, Ministry of Communications.Practical application of paraffin paper manufacturing technology for capacitors in Japan
  3. ^ Marine Engineering Apr.1900 Aldrich & Donaldson p173
  4. ^ CS Franklin "Short-Wave Directional Wireless Telegraphy" The Wireless World and radio review May 20,1922 The official organ of the wireless society of London p221
  5. ^ "History of Japanese Broadcasting" 1951 Edition Japan Broadcasting Corporation pp16-17
  6. ^ Guglielmo Marconi "Radio Communications" Journal of the Royal Society of ArtsVol.73 --No.3762 Dec.26,1924 pp125-126
  7. ^ Noboru Maruge "Transatlantic Radiotelephone" "Radio" 1924.1 Ministry of Communications Radio Club p11
  8. ^ GCBRowe "" Hello London! "" Are you there, New York? "" Radio news Mar.1927 Experimenter Publishing Company p1048
  9. ^ "Broadcasting Complete American Programs to All England" Broadcast RadioVol4 March1924 Doubleday Doran Inc. pp359-364
  10. ^ "WIRELESS TELEPHONY FROM ENGLAND TO AUSTRALIA" The Brisbane Courier June 4,1924 p7
  11. ^ "Telephony on 18 centimetres" Wireless World Apr.15,1931 p393
  12. ^ "Very High Frequency Radio Using Small Reflectors = New British Attempt =" "Yomiuri Shimbun" May 1934, 9 (Showa 5) Morning edition p8
  13. ^ "MARCONI INITIATES NEW RADIOPHONE: The First Ultrashort Wave System Links Vatican and Papal Summer Home" The New York Times Feb.12,1933 p24
  14. ^ Hideo Nigami "Fukushima Bunko 39 Haramachi Radio Tower Story"
  15. ^ Takehiko Yamamura "A little good story about the Great Kanto Earthquake / Tomioka Radio Station that has been transmitting to the world immediately after the earthquake"
  16. ^ Yoichi Katayori "Great Kanto Earthquake and Radio Telegraph (Iwaki Radio Telegraph Station Tomioka Station) (PDF)"
  17. ^ Kaichiro Yonemura"Radio Wave World 50 Years" (serialized "Memorial Note" 11th) "Radio Time Signal" September 1959
  18. ^ Kaichiro Yonemura "50 Years of the Radio World" (serialized "Notes of Memories" 12th) "Radio Time Signal" October 1959

Related item


Back to Top