Title :
Design and performance of quasi-synchronous multi-carrier CDMA system
Author :
Tsumura, Shigehiko ; Hara, Shinsuke
Author_Institution :
Dept. of Electron., Inf. Syst. & Energy Eng., Osaka Univ., Japan
fDate :
6/23/1905 12:00:00 AM
Abstract :
Multicarrier (MC)-CDM/CDMA is one of the promising code division-based multiple access/multiplexing techniques for fourth-generation mobile communications systems, where high data rate services will be provided even for high speed-cruising mobiles. Investigations so far made in Japan have shown that the MC-CDM scheme has superiority over the direct sequence (DS)-CDM scheme in the downlink; on the other hand, the MC-CDMA scheme is not so advantageous over the DS-CDMA scheme in the uplink. This is because the code orthogonality among users can be kept in the downlink, whereas it is totally distorted by frequency selective fading in the uplink. First, we show a new signal design for MC-CDM/CDMA transmission. The new signal format has head/tail guard intervals in one symbol duration, for accurate DFT window synchronization in downlink and uplink, and establishment of quasi-synchronous transmission in uplink. Then, we show the bit error rate performance for MC-CDM with minimum mean square error (MMSE)-based combining in downlink and MC-CDMA with MMSE-based multiuser detection in uplink
Keywords :
code division multiple access; data communication; discrete Fourier transforms; error statistics; least mean squares methods; mobile radio; multiuser channels; packet radio networks; packet switching; synchronisation; DFT window synchronization; Japan; MC-CDM/CDMA; MMSE-based combining; bit error rate; code division multiple access; code orthogonality; downlink; fourth-generation mobile communications; head/tail guard intervals; high data rate services; minimum mean square error; multi-carrier CDMA system; multiplexing; multiuser detection; performance; quasi-synchronous CDMA system; quasi-synchronous transmission; uplink; Bit error rate; Downlink; Fading; Frequency synchronization; Mean square error methods; Mobile communication; Multiaccess communication; Multicarrier code division multiple access; Signal design; Tail;
Conference_Titel :
Vehicular Technology Conference, 2001. VTC 2001 Fall. IEEE VTS 54th
Conference_Location :
Atlantic City, NJ
Print_ISBN :
0-7803-7005-8
DOI :
10.1109/VTC.2001.956891
