DocumentCode :
1430952
Title :
Performance limits of Reed-Solomon coded CDMA with orthogonal signaling in a Rayleigh-fading channel
Author :
Kim, Sang Wu ; Stark, Wayne
Author_Institution :
Dept. of Electr. Eng., Korea Adv. Inst. of Sci. & Technol., Taejon, South Korea
Volume :
46
Issue :
9
fYear :
1998
fDate :
9/1/1998 12:00:00 AM
Firstpage :
1125
Lastpage :
1134
Abstract :
The asymptotic performance of Reed-Solomon (RS)-coded M-ary orthogonal signaling with ratio-threshold test (RTT) type demodulation in a Rayleigh-fading channel is considered. We show that the minimum E¯b/N0 needed for error-free communication is eln2 (2.75 dB) with RTT, and 4.79 (6.8 dB) with hard decisions. The optimum code rate that minimizes the required E¯b/N0 is e-1 with RTT and 0.46 with hard decision, and the optimum ratio threshold approaches 1 for large M. Next, we investigate the fundamental limit in a direct-sequence spread-spectrum multiple-access (DS/SSMA) system employing an M-ary orthogonal code of length N=Mm, which is obtained by spreading every row of an M×M Hadamard matrix with a user-specific random sequence of length N. We derive the minimum E¯b/N0 for error-free communication as a function of the number of users, the optimum code rate that minimizes E¯B/N0, and the maximum limit on the total information transmission rate. Then, we consider a multirate DS/SSMA system, where a population of users simultaneously transmit at different power levels a variety of traffic types of different information rates. We derive the minimum required E¯B/n0 and the optimum code rate for each traffic type
Keywords :
Hadamard matrices; Rayleigh channels; Reed-Solomon codes; code division multiple access; demodulation; fading; spread spectrum communication; telecommunication signalling; DS/SSMA; Hadamard matrix; M-ary orthogonal code; M-ary orthogonal signaling; Rayleigh-fading channel; Reed-Solomon coded CDMA; asymptotic performance; direct-sequence spread-spectrum multiple-access; error-free communication; hard decisions; information rates; optimum code rate; optimum ratio threshold; orthogonal signaling; performance limits; ratio-threshold test type demodulation; traffic types; user-specific random sequence; Demodulation; Error correction; Error correction codes; Information rates; Multiaccess communication; Random sequences; Rayleigh channels; Reed-Solomon codes; Spread spectrum communication; Testing;
fLanguage :
English
Journal_Title :
Communications, IEEE Transactions on
Publisher :
ieee
ISSN :
0090-6778
Type :
jour
DOI :
10.1109/26.718555
Filename :
718555
Link To Document :
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