ウィルコムの2.5GHz帯周波数免許取得に対してPHS MoU Groupがお祝いコメントを掲載

PHSの普及団体「PHS MoU Group」がウィルコムが2.5GHz帯BWAシステムにおけて「次世代PHS(XG-PHS/XGP)」で周波数獲得認定を受けたことに対してNewsletterにてお祝いコメントを掲載しています。といっても,まだウェブサイトには掲載されていないっぽく,メールマガジンのみでとなっているのかな?サイトに掲載されるまでは転載しちゃっておきますかね(マズイかね?)。コメントは,PHS MoU Groupの議長および副議長,そしてウィルコムの副社長である近義起氏の3氏から寄せられています。また,暇?人さんのところに非常にわかりやすい次世代PHSの技術概要ができてますよ♪先のNewsletterによると,現在,PHS MoUにて公開されている次世代PHSの規格はVer.01 Rev.02ですが,すでに10月にVer.01 Rev.03ができているとのこと。後,ふぇちゅいんさんが記念プレゼント企画を開始されていて,なんと応募者全員にプレゼントを送付するという暴挙に出ていますw あぁやって応募敷居を上げれば全員も可能なのかな…。送付するのがめんど(ry

WILLCOM Obtained 2.5GHz Domestic License for Next-Generation PHS in Japan

WILLCOM obtained license to use 2.5GHz radio frequency in order to carry out BWA* service in Japan.The Ministry of Internal Affairs announced on December 21st that the licenses to use the 2.5GHz radio frequency on condition of carrying out BWA service were granted to WILLCOM Corp. for Next-Generation PHS service and KDDI Alliance for WiMAX service. While any of the investors of an existing 3G operator can apply for the 2.5GHz license as long as it holds less than one third of the operator, application from any of the 3G operators itself is not accepted. At this time when license is granted, the way to use the license is still under discussion. As a result, WILLCOM won one license for Next-Generation PHS, and the other license went to the alliance of the three 3G operators who support WiMAX and applied the license to commercialize this BWA method via their investors who holds less than one third of the three operators each. After a long time waiting, it turns out that there are only two licenses granted this time.One is for the Japan-generated technology of Next-Generation PHS and the other is for WiMAX advocated by Intel. Despite the fact that WiMAX has already become an international focus, Next-Generation PHS is superior at mobility comparing to other BWA systems. We believe that the service to be started by WILLCOM by 2009 will be worthy of your waiting and expectation. * BWA(Broadband Wireless Access)

Congratulatory Address from Mr. Inoue, Chairperson of PHS MoU Group

[IMG] phsmouchairmaninoue.jpgThis is really big news. But, it is also a natural decision. After repeated discussion in MoU, Next-Generation PHS Specification has been approved earlier this year. Now the time to think about practical use of the technology in Japan has come. To add to the already widely used PHS service, 2.5GHz bandwidth is granted to Next-Generation PHS, which will surely bring a blossom to wireless broadband service in Japan. Plural users can enjoy wireless broadband without deterioration of communication quality in urban areas with dense population, owning to Next-Generation PHS’ bi-directional rapidity, adding to the essential advantage of circumspectly deployed PHS system. Based on the past achievement, PHS MoU Group is ready to cooperate with any countries/areas in the world in hope to introduce and expand Next-Generation PHS technology.

Congratulatory Address from Mr. Wakao, Vice Chairperson of PHS MoU Group

[IMG] phsmouvicechairmanwakao.jpgMinistry of Internal Affairs has decided to release licenses for Japan’s new broadband wireless access (BWA) service to WILLCOM Inc., which is to adopt Next-Generation PHS and one more company, which will adopt WiMax With this decision, Next-Generation is officially accepted as a feasible solution for BWA system in Japan. This is delightful news to PHS MoU Group. The group, as well as its members is sharing the celebratory moment with WILLCOM Inc.Besides, Next-Generation PHS Specification drafted by PHS MoU Group was accepted as an ARIB (Association of Radio Industry and Businesses) standard obtaining in Japan on December 12. I want to take this opportunity to thank all members of PHS MoU Group for their efforts to standardize the specification. Finally, sincerely wish PHS industry to take good grasp of this chance and develop bigger and bigger in future.

Congratulatory Address from Mr. Chika, Vice Chairperson of PHS MoU Group

[IMG] willcomvicepresidentchika.jpgIt is a great pleasure to hear the news because today’s decisionis to effect hugely to the future development of the whole PHS industry. We are expecting to start appealing the world with technical priority of Next Generation PHS, by confronting WiMax directly and defeating it in competition. To the interest of WILLCOM Inc., I would like to call for constant support from all of you who involved in PHS business, in hope to introduce and apply Next-Generation PHS service as soon aspossible. Thank you.

Introduction of Next Generatrion PHS Technology

This is an introduction of Next-Generation PHS technology, of which WILLCOM Corp. has just obtained the 2.5GHz radio frequency license as an officially recognized Broadband Wireless Access in Japan. Next-Generation PHS is a high-throughput huge-capacity telecommunication system that adopts both TDMA/TDD and OFDMA technologies. Inheriting the micro-cell and DCA (Dynamic Channel Assign) features of the existing PHS (advanced PHS included), Next-Generation PHS is developed as a more efficient and faster mobile technology that is to be commercialized in Japan soon.The specification of Next-Generation PHS, titled A-GN4.00-01-TS Ver.01 Rev.02, and approved by the general meeting of PHS MoU Group in September 2007 is briefed in the following chapters. [Note : Latest version of Next Generation PHS specification is Ver.01 Rev.03 which was updated on October 2007.]

Specifiction of PHSY Layer

Of the multiple access methods of Next-Generation PHS, OFDMA/TDMA method is adopted for DL (downlink), while OFDMA/TDMA and SC-FDMA/TDMA methods are adopted for UL (Uplink). Mixed use of OFDMA/TDMA and SC-FDMA/TDMA at UL stage is possible. The structure of a TDMA frame issymmetrical, with 4 slots at 625 us for UL and 4 slots at 625 us for DL. This structure, which is identical with that of the existing PHS, builds the mutual base for co-existence of the two PHS systems. TDD is adopted as the duplex method.

The following chart describes the major technical index used for Next-Generation PHS.
Duplex method TDD
Downlink access method OFDMA/TDMA
Uplink access method OFDMA, SC-FDMA/TDMA
TDMA slot period 625 us
TDMA frame period 5 ms
Number of slots in one frame 8 slots, 4 slots for transmission and 4 slots for reception symmetrically
The following chart shows the OFDM parameter of Next-Generation PHS.
Parameter Type1 Type2 Type3 Type4 Type5 Type6 Type7
System Bandwidth [MHz] 2.5 5 10 10 20 20 20
Effective channel bandwidth [MHz] 1.8 3.6 8.1 9.0 16.2 17.1 18.0
Used subcarrier number 48 96 216 240 432 456 480
Subcarrier spacing [kHz] 37.5
Subchannel bandwidth [kHz] 900
Guard Interval length [us] 6.66 (For first OFDM symbol)
3.33 (For other symbols)
OFDM Data length [us] 26.67
OFDM symbol length [us] 33.3 (For first OFDM symbol)
30 (For other symbols)
Guard Interval ratio 1/4 (For first OFDM symbol)
1/8 (For other symbols)
Total Guard Time [us] 51.67 (21.67 + 30)
OFDM symbol number per subcarrier 19
Specification of MAC Layer

Radio resource is managed and controlled in MAC layer of Next-Generation PHS by QS-Mode(high quality channel based on carrier-sensing mode)and FM-Mode(fast access channel based on MAP mode). In QS-Mode, one PRU (Physical Resource Unit)will be assigned fixedly as a CSCH (Circuit Switching Channel) according to the result of carrier sense after an access request is received. As the assigned CSCH is occupied by one user at all times, it guarantees that this one user will be able to occupy a certain radio bandwidth too. Hence, QS-Mode is a perfect choice to carry out service that requires real-time voice communication when data occurs randomly. In FM-Mode, one PRU will be assigned as a ANCH(Anchor Channel)according to the result of carrier sense after an access request is received. ANCH dedicated user control information as one user is assigned once. The PRU for communication assigns EXCH (Extra Channel) in every 5 ms according to MAP which contains information elements from ANCH. That is, EXCH is not exclusively taken by one user, but shared by multiple users. FM-Mode is a perfect choice to carry out high-speed data service as it holds the ability to correspond to the burst change of data amount swiftly. By using QCS-ID(QoS Control Session Identifier)in Next-Generation PHS, providing multiple qualified services (eg: voice plus e-mail reception) to one user becomes possible.

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