The
Personal Handy-phone System (
PHS), also marketed as the
Personal Access System (
PAS) and commercially branded as
Xiaolingtong (小灵通) in
ChinaChina is a cultural region, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
, is a mobile network system operating in the 1880–1930 MHz frequency band, used mainly in
Japanis an island country in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, People's Republic of China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
,
ChinaChina is a cultural region, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
,
TaiwanTaiwan , also known as Formosa , is the largest island of the Republic of China in East Asia. Taiwan is located east of the Taiwan Strait, off the southeastern coast of mainland China...
and some other
AsiaAsia is the world's largest and most populous continent, located in the eastern and northern hemispheres. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population.Asia is traditionally defined as part of the...
n countries.
Technology
PHS is, essentially, a
cordless telephoneA cordless telephone or portable telephone is a telephone with a wireless handset that communicates via radio waves with a base station connected to a fixed telephone line, usually within a limited range of its base station...
like
DECTDigital Enhanced Cordless Telecommunications , known as Digital European Cordless Telephone until 1995, is an ETSI standard for digital portable phones , commonly used for domestic or corporate purposes. It is recognised by the ITU as fulfilling the IMT-2000 requirements and thus qualifies as a 3G...
, with the capability to
handoverIn cellular telecommunications, the term handoff refers to the process of transferring an ongoing call or data session from one channel connected to the core network to another. In satellite communications it is the process of transferring satellite control responsibility from one earth station to...
from one
cellA cellular network is a radio network made up of a number of radio cells each served by at least one fixed-location transceiver known as a cell site or base station...
to another. PHS cells are small, with transmission power of
base stationThe term base station can be used in the context of land surveying, wireless computer networking, and wireless communications.-Land surveying:...
a maximum of 500 mW and range typically measures in tens or at most hundreds of meters (some can range up to about 2 kilometres in line-of-sight), as opposed to the multi-kilometer ranges of CDMA and GSM. This makes PHS suitable for dense urban areas, but impractical for rural areas, and the small cell size also makes it difficult if not impossible to make calls from rapidly moving vehicles.
PHS uses
TDMATime division multiple access is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using his own time slot. This...
/TDD for its radio
channel access methodIn telecommunications and computer networks, a channel access method or multiple access method allows several terminals connected to the same multi-point transmission medium to transmit over it and to share its capacity...
, and 32 kbit/s ADPCM for its voice
codecA codec is a device or computer program capable of encoding and/or decoding a digital data stream or signal. The word codec is a portmanteau of compressor-decompressor' or, more accurately, coder-decoder'.Historically a modem was a contraction of modulator/demodulator and converted...
. Modern PHS phone can also support many
value-added serviceA value-added service is popular as a telecommunications industry term for non-core services or, in short, all services beyond standard voice calls and fax transmissions but, it can be used in ANY service industry for the services providers provide for no cost to promote their main service business...
s such as high speed wireless
dataThe term data means groups of information that represent the qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables...
/
InternetThe Internet is a global system of interconnected computer networks that use the standardized Internet Protocol Suite to serve billions of users worldwide...
connection (64 kbit/s and higher),
WWWThe World Wide Web is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view Web pages that may contain text, images, videos, and other multimedia and navigate between them using hyperlinks...
access,
e-mailElectronic mail, often abbreviated as email or e-mail, is a method of exchanging digital messages, designed primarily for human use...
ing, text messaging and even color image transfer.
PHS technology is also a popular option for providing a
wireless local loopWLL redirects here. Not to be confused with Weight Load Limit, the maximum weight that a given apparatus can bearWireless local loop , is a term for the use of a wireless communications link as the "last mile / first mile" connection for delivering plain old telephone service and/or broadband...
, where it is used to bridge the "
last mileThe "last mile" is the final leg of delivering connectivity from a communications provider to a customer. The phrase is therefore often used by the telecommunications and cable television industries. The actual distance of this leg may be considerably more than a mile, especially in rural areas...
" gap between the
POTSPlain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in most parts of the world. The name is a retronym, and is a reflection of the telephone service still available after the...
network and the subscriber's home. Actually, it was developed under the concept that it makes up a wireless front-end of an
ISDNIntegrated services digital network is a set of communications standards enabling traditional telephone lines to carry voice, digital network services, and video. Prior to ISDN, the phone system was viewed as a way to transport voice, with some special services available for data...
network. So a base station of PHS has a compatibility with, and is often connected directly to ISDN
telephone exchangeIn the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...
equipment (A.K.A. a digital switch).
As for its low-price
base stationThe term base station can be used in the context of land surveying, wireless computer networking, and wireless communications.-Land surveying:...
,
micro-cellularA microcell is a cell in a mobile phone network served by a low power cellular base station , covering a limited area such as a mall, a hotel, or a transportation hub. A microcell is usually larger than a picocell, though the distinction is not always clear. A microcell uses power control to limit...
system and "Dynamic Cell Assign" system, PHS can afford more number-of-digits
frequencyFrequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency....
use efficiency with lower cost (
throughputIn communication networks, such as Ethernet or packet radio, throughput or network throughput is the average rate of successful message delivery over a communication channel. These data may be delivered over a physical or logical link, or pass through a certain network node...
per area basis), compared with typical 3G cellular telephone systems. It makes possible the flat-rate wireless service such as AIR-EDGE all over Japan.
The speed of AIR-EDGE data connection is accelerated by combining lines, each of which basically is 32 kbit/s. AIR-EDGE 1x or first version introduced in 2001 provide only 32 kbit/s service. In 2002, 128 kbit/s service (AIR-EDGE 4x) started. In 2005, 256 kbit/s (AIR-EDGE 8x) service started.
In 2006, the speed of each line was also up-graded to 1.6 times with the introduction of "W-OAM" technology. The speed of AIR-EDGE 8x is up to 402 kbit/s with the latest "W-OAM" capable instrument.
In April 2007, "W-OAM typeG" was introduced allowing data speeds of 512 kbit/s for AIR-EDGE 8x users. Furthermore, the "W-OAM typeG" AIR-EDGE 8x service is planned to be upgraded to a maximum throughput of 800 kbit/s, when the upgrading for access points (mainly switching lines from ISDN to
fibre opticAn optical fiber is a glass or plastic fiber that carries light along its length. Fiber optics is the overlap of applied science and engineering concerned with the design and application of optical fibers...
) in its system are completed. And it may exceeds the speeds of popular
W-CDMAW-CDMA , UMTS-FDD, UTRA-FDD, or IMT-2000 CDMA Direct Spread is an air interface found in 3G mobile telecommunications networks. It is the basis of Japan's NTT DoCoMo's FOMA service and the most-commonly used member of the UMTS family and sometimes used as a synonym for UMTS...
3G service like
NTT DoCoMois the predominant mobile phone operator in Japan. The name is officially an abbreviation of the phrase, "do communications over the mobile network", and is also from a compound word dokomo, meaning "everywhere" in Japanese...
's
FOMAThe word Foma has several meanings:* Foma is a term in the fictional Bokononist religion in Kurt Vonnegut's novel Cat's Cradle. It is a comforting lie that has value independent of its truth ....
in Japan.
Implementation
Originally developed by
NTT Laboratory, commonly known as NTT, is a telephone company that dominates the telecommunication market in Japan. Ranked the 44th in Fortune Global 500, NTT is the largest telecommunications company in Asia, and the second-largest in the world in terms of revenue....
in
Japanis an island country in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, People's Republic of China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
in 1989 and far simpler to implement and deploy than competing systems like PDC or GSM, the commercial services has been started by three PHS operators (NTT-Personal, DDI-Pocket and ASTEL) in Japan in 1995. However, the service has been pejoratively dubbed as the "poor man's cellular", due to its limited range and roaming abilities. Market share in Japan has been declining and NTT DoCoMo, which has absorbed NTT Personal, and ASTEL is going to terminate the PHS service. Some of other countries have already terminated offering PHS services and migrated to GSM.
But PHS has seen a resurgence in markets like
ChinaChina is a cultural region, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
,
TaiwanTaiwan , also known as Formosa , is the largest island of the Republic of China in East Asia. Taiwan is located east of the Taiwan Strait, off the southeastern coast of mainland China...
,
VietnamVietnam , officially the Socialist Republic of Vietnam , is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea to the east...
,
Bangladesh, officially the People's Republic of Bangladesh is a country in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south...
,
NigeriaNigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising thirty-six states and one Federal Capital Territory. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger...
,
MaliMali, officially the Republic of Mali , is a landlocked nation in Western Africa. Mali is the seventh largest country in Africa, bordering Algeria on the north, Niger on the east, Burkina Faso and the Côte d'Ivoire on the south, Guinea on the south-west, and Senegal and Mauritania on the west...
,
TanzaniaThe United Republic of Tanzania is a country in central East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi and the Democratic Republic of the Congo to the west, and Zambia, Malawi and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.The United...
and
HondurasHonduras is a republic in Central America. It was formerly known as Spanish Honduras to differentiate it from British Honduras...
where its low deployment costs (estimated to be as low as 20% of a GSM network) make it attractive to operators.
Wireless local loopWLL redirects here. Not to be confused with Weight Load Limit, the maximum weight that a given apparatus can bearWireless local loop , is a term for the use of a wireless communications link as the "last mile / first mile" connection for delivering plain old telephone service and/or broadband...
(WLL) systems based on PHS technology are in use in some of the above-mentioned countries. In recent years,
WILLCOMis a Japanese PHS operator, offering flat-rate wireless network data transmission and flat-rate voice calls for its subscribers.The company was formerly known as DDI Pocket, a subsidiary of KDDI. In 2004, the Carlyle Group acquired a majority stake from KDDI and changed the name of the company in...
, formerly DDI-Pocket, is introducing flat-rate
wireless networkWireless network refers to any type of computer network that is wireless, and is commonly associated with a telecommunications network whose interconnections between nodes is implemented without the use of wires...
and flat-rate calling in Japan, which has reversed the local fate of PHS up to an extent. In China, there was seen an explosive expansion of subscribers until around 2005, but it has been calming down in 2006. In
ChileChile, officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
, Telefónica del Sur on March 2006 launched a PHS based telephony service in some cities of the southern part of the country. In
BrazilBrazil , officially the Federative Republic of Brazil , is a country in South America. It is the fifth largest country by geographical area, occupying nearly half of South America, the fifth most populous country, and the fourth most populous democracy in the world. Bounded by the Atlantic Ocean...
, Suporte Tecnologia has a PHS based telephony service in
BetimBetim is a city in Minas Gerais, Brazil. It is located at around . The city belongs to the mesoregion Metropolitana de Belo Horizonte and to the microregion of Belo Horizonte....
, state of Minas Gerais, and Transit Telecom has announced a rollout of a PHS network in 2007.
China TelecomChina Telecom Corp. Ltd. is the largest fixed line service and 3rd largest mobile telecommunication provider in the People's Republic of China.-Sectors:...
operates a PAS system in China, even though technically it was not regarded as allowed to provide mobile services, because of some particularities of the Chinese governance.
China NetcomChina Netcom, full name China Netcom Group Corporation Limited , abbreviated CNC, was formed in August 1999 by the People's Republic of China government to enable inward investments to build high speed Internet communications in the country...
, the other fixed-line operator in China, also provides Xiaolingtong service. The system was a runaway hit, with over 90 million subscribers signed up . The largest vendors of the system are
UTStarcomUTStarcom is a Fortune 1000 company that specializes in IP-based networking products for telecommunications companies and service providers. Its core markets are multimedia communications and broadband, including IP communications and entertainment , next generation broadband networks and optical...
and
ZTEZTE is a global provider of telecommunications equipment and network products based in Shenzhen.ZTE was established in 1985...
. However, low priced mobile phones are rapidly replacing PHS. The Ministry of Industry and Information Technology of the People's Republic of China issued notices on 13 February 2009 that both registration of new users and expansion of the network were to be discontinued with the service to be ended by the end of 2011 .
A PHS global roaming service is available between Japan (WILLCOM), Taiwan and Thailand.
International development
- PHS's subscribers and major operators
- Japan : 4,517,700 (July, 2009)
- Willcom
is a Japanese PHS operator, offering flat-rate wireless network data transmission and flat-rate voice calls for its subscribers.The company was formerly known as DDI Pocket, a subsidiary of KDDI. In 2004, the Carlyle Group acquired a majority stake from KDDI and changed the name of the company in...
- China : 75,200,000 (September, 2008)
- China Telecom
China Telecom Corp. Ltd. is the largest fixed line service and 3rd largest mobile telecommunication provider in the People's Republic of China.-Sectors:...
, China NetcomChina Netcom, full name China Netcom Group Corporation Limited , abbreviated CNC, was formed in August 1999 by the People's Republic of China government to enable inward investments to build high speed Internet communications in the country...
- Taiwan : 1,457,463 (3 quarter 2008)
- FITEL
- Thailand : PCT
- Geography :* Pacific Crest Trail, a hiking trail that runs along the west coast of the United States, from Mexico to Canada* Princeton Airport - Science :* Patent Cooperation Treaty, an international patent treaty...
, Asia wireless communication
- Other major countries: Vietnam, Chile, Brazil
External links