Personal Handy-phone System

The Personal Handy-phone System (PHS), also marketed as the Personal Access System (PAS) and commercially branded as Xiaolingtong (Chinese: 小灵通) in Mainland China, is a mobile network system operating in the 1880–1930 MHz frequency band, used mainly in Japan, China, Taiwan, and some other Asian countries and regions.

Outline

Technology

PHS Japan 1997–2003 (Willcom, NTT DoCoMo, ASTEL)

PHS is essentially a cordless telephone like DECT, with the capability to handover from one cell to another. PHS cells are small, with transmission power of base station a maximum of 500 mW and range typically measures in tens or at most hundreds of metres (some can range up to about 2 kilometres in line-of-sight), contrary to the multi-kilometre 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 TDMA/TDD for its radio channel access method, and 32 kbit/s ADPCM for its voice codec. Modern PHS phone can also support many value-added services such as high speed wireless data/Internet connection (64 kbit/s and higher), WWW access, e-mailing, and text messaging.

PHS technology is also a popular option for providing a wireless local loop, where it is used for bridging the "last mile" gap between the POTS network and the subscriber's home. It was developed under the concept of providing a wireless front-end of an ISDN network. Thus a base station of PHS is compatible with ISDN and is often connected directly to ISDN telephone exchange equipment e.g. a digital switch.

In spite of its low-cost base station, micro-cellular system and "Dynamic Cell Assignment" system, PHS offers higher number-of-digits frequency use efficiency with lower cost (throughput per area basis), compared with typical 3G cellular telephone systems. It enables the flat-rate wireless service like AIR-EDGE throughout Japan.

The speed of AIR-EDGE data connection is accelerated by combining lines, each of which basically is 32 kbit/s. AIR-EDGE 1× or first version introduced in 2001 provide only 32 kbit/s service. In 2002, 128 kbit/s service (AIR-EDGE 4×) started. In 2005, 256 kbit/s (AIR-EDGE 8×) 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 8× 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 8× 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 optic) in its system are completed. And it may exceed the speeds of popular W-CDMA 3G service like NTT DoCoMo's FOMA in Japan.

Implementation

ASTEL-brand PHS Base station in Tokyo, Japan

Originally developed by NTT Laboratory in Japan 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 forming the PIAF (PHS Internet Access Forum). 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 terminated the PHS service in January 2008. Most other countries with PHS networks, have also terminated offering PHS services and migrated to GSM.

Wireless local loop (WLL) systems based on PHS technology are in use in some of the above-mentioned countries. In recent years, WILLCOM, formerly DDI-Pocket, is introducing flat-rate wireless network 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 Chile, Telefónica del Sur launched a PHS-based telephony service in some cities of the southern part of the country in March 2006. In Brazil, Suporte Tecnologia has a PHS-based telephony service in Betim, state of Minas Gerais, and Transit Telecom has announced a rollout of a PHS network in 2007.

China Telecom operated 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 Netcom, the other fixed-line operator in China, also provides Xiaolingtong service. The system was a runaway hit, with over 90 million subscribers signed up as of 2007. The largest vendors of the system are UTStarcom and ZTE. 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.^[1]

A PHS global roaming service was available between Japan (WILLCOM), Taiwan, and Thailand.

Commercial deployments

This is a list of commercial PHS deployments around the world:^[2]

Country	Operator	ƒ (MHz)	Launch date	End of service	Notes
Brazil	Transit Telecom	1910 - 1920	000000002008-01-01-00002008 (?)		[3][4][5]
Japan	Softbank (Y!mobile)	1884,65 - 1919,45	000000001995-07-01-0000Jul 1995		[6][7][8][9][10][11][12][13][14][15] Willcom merged with eAccess to Y!mobile in 2014. Operated by Carlyle (Willcom) (2004 - 2010). Operated by KDDI (DDI Pocket) (1995 - 2004). 070 prefix under the Japanese telephone numbering plan.

Defunct networks

Country	Operator	ƒ (MHz)	Launch date	End of service	Notes
China	China Unicom	1880 - 1920	000000001998-01-01-00001998	000000002013-09-01-0000Sep 2013	[16][17] Operated under the name "Xiaolingtong (XLT)" and "Little Smart".
Hong Kong	(?)	1895 - 1906,1	000000001997-01-01-00001997	000000002016-05-01-0000May 2016	[18][19][20][21]
Japan	NTT DoCoMo	1884,65 - 1919,45	000000001995-07-01-0000Jul 1995	000000002008-01-01-0000Jan 2008	[6][22][23][24][25][26]
Taiwan	Fitel	1905 - 1915	000000002001-05-01-0000May 2001	000000002015-03-01-0000Mar 2015	[27][28][29][30][31][32]
Chile	Telefónica del Sur	1910 - 1930	000000002006-03-01-0000Mar 2006	000000002011-05-01-0000May 2011	[33][34][35]

List of PHS enabled CompactFlash cards

PHS-enabled PCMCIA/CompactFlash cards include:

• TDK DF56CF
• NTT DoCoMo P-in Comp@ct
• NTT DoCoMo P-in m@ster
• NTT DoCoMo P-in memory
• DDI AirH”Card petit [RH2000]
• DDI AirH”Card petit [CFE-02]
• DDI C@rdH”64 petit [CFE-01]
• DDI C@rdH”64 petit [CFE-01/TD]

See also

• OpenBTS

References

External links

Wikimedia Commons has media related to PHS.

• PHS MoU Group (PHS MoU was dissolved and absorbed into a new organization "XGP Forum" in 2009.
• Article on Xiaolingtong
• PHS in Taiwan
• Telefonica del Sur in Chile