Title :
Downlink Site Diversity with Frequency-Domain Equalization for a DS-CDMA Cellular System
Author :
Sato, Hirotaka ; Tomeba, Hiromichi ; Takeda, Kazuaki ; Adachi, Fumiyuki
Author_Institution :
Dept. of Electr. & Commun. Eng., Tohoku Univ.
Abstract :
In DS-CDMA high speed wireless signal transmissions, the bit error rate (BER) performance with coherent rake combining degrades due to inter-path interference (IPI) caused by a severe frequency-selective fading. The use of frequency-domain equalization (FDE) can significantly improve the BER performance. However, the local average received signal power slowly varies due to path loss and shadowing loss according to the movement of a mobile user. This variation degrades the link capacity particularly when the user is located close to the cell edge. To improve the link capacity, the well-known site diversity can be used in conjunction with FDE. In this paper, we present downlink site diversity with FDE for a DS-CDMA cellular system and derive the MMSE weight for site diversity combining. The downlink capacity is evaluated by computer simulation and compared to the case with coherent rake combining. Then it is shown that the link capacity with FDE is better than that with coherent rake combining
Keywords :
cellular radio; code division multiple access; diversity reception; equalisers; error statistics; fading channels; frequency-domain analysis; least mean squares methods; spread spectrum communication; BER; DS-CDMA cellular system; FDE; IPI; MMSE; bit error rate; coherent rake combining; direct sequence code division multiple access; downlink site diversity combining; frequency-domain equalization; frequency-selective fading; interpath interference; link capacity; minimum mean square error methods; wireless signal transmission; Bit error rate; Computer simulation; Degradation; Diversity reception; Downlink; Fading; Frequency; Interference; Multiaccess communication; Shadow mapping;
Conference_Titel :
Communication systems, 2006. ICCS 2006. 10th IEEE Singapore International Conference on
Conference_Location :
Singapore
Print_ISBN :
1-4244-0411-8
Electronic_ISBN :
1-4244-0411-8
DOI :
10.1109/ICCS.2006.301489
