tailieunhanh - Next generation wireless systems and networks jul 2006 phần 5

Các tốc độ dữ liệu phù hợp với phạm vi điều kiện kênh có kinh nghiệm trong một tế bào điển hình hoặc mạng PCS. QPSK điều chế được sử dụng để đạt được 38,4 kbps thông qua 1228,8 kbps tốc độ dữ liệu (ngoại trừ 921,6 kbps), 8PSK cho 921,6 kbps và 1843,2 kbps và 16QAM 1228,8 kbps và 2457,6 kbps | 192 3G MOBILE CELLULAR TECHNOLOGIES WCDMA cdma2000 NEC NTT ETRI DACOM Ericsson Nokia Eastern Telecom Chongxing Huawei Da-Tang Telecom Siemens Link Air TD-SCDMA Forum Beijing Ericsson Nanjing Ericsson Qualcomm SK Telecom Samsung Da-Tang Giant Dragon Chongxing Huawei Eastern Telecom Beijing Post Telecom Shanghai Bell and so on. TD-SCDMA Figure The major companies research groups involved in the activities to develop 3- and 4G mobile communication systems in China. China 3G Union China Mobile China Unicom Da-Tang Telecom Huawei Siemens Motorola Nortel and other 210 firms LAS-CDMA LinkAir seriously involved with the TD-SCDMA platform development. It is clear that the company considers TD-SCDMA technology to be a vital 3G solution with great opportunity for success. Siemens has noticeably lead other foreign competitors in TD-SCDMA system development. Currently Siemens has invested a large amount in TD-SCDMA R D facilities in China where it has recruited several hundred research personnel working in the TD-SCDMA system. Several Korean companies and institutions such as Samsung and ETRI have also expressed a keen interest in TD-SCDMA systems development. In 2001 CATT also sent a large delegation to Taiwan to seek possible collaboration with Taiwanese companies in chip set design silicon wafer fabrication support and so on. Since China has the largest number of GSM subscribers in the world the technical similarity especially in mobile CNs between TD-SCDMA and GSM gives an advantage to those GSM operators who upgraded their networks into TD-SCDMA at a relatively low cost in comparison with opting for other 3G standards. CATT estimates that the saving in the upgrading cost can be as much as 30 . Currently both CATT and Siemens are developing dual-mode and dual-band terminals for use in GSM and TD-SCDMA networks to suit the great needs in the transition period from 2- to 3G systems in China as well as other regions where the TD-SCDMA will be selected as a 3G solution for

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