Title :
Comparison of multiple access interference in asynchronous MC-CDMA and DS-CDMA systems
Author :
Carey, Daniel ; Roviras, Daniel ; Senadji, Bouchra
Author_Institution :
INPT/ENSEEIHT-IRIT, Toulouse, France
Abstract :
In this paper we make a comparison between the multiple access interference (MAI) incurred in asynchronous multicarrier code division multiple access (MC-CDMA) and direct-sequence code division multiple access (DS-CDMA) systems for uplink satellite communications. Using a symbol by symbol recovery approach, we characterize the MAI produced by both systems in the absence of additive channel noise. For a given set of transmission offsets, the bit-error-rate (BER) is computed, and analyzed for an increasing number of users. This analysis has been performed for codelength´s of N = 8 (using Walsh-Hadamard codes) and N = 7 (using Gold codes). Simulations show that, on average, the MC-CDMA scheme outperforms DS-CDMA in an asynchronous non-selective environment for the spreading codes considered.
Keywords :
Hadamard codes; code division multiple access; error statistics; radiofrequency interference; satellite communication; spread spectrum communication; DS-CDMA systems; Gold codes; Walsh-Hadamard codes; asynchronous MC-CDMA systems; asynchronous nonselective environment; bit-error-rate; direct-sequence code division multiple access systems; multicarrier code division multiple access systems; multiple access interference; spreading codes; symbol by symbol recovery approach; uplink satellite communications; Additive noise; Bit error rate; Computational modeling; Fading; Gold; Mobile communication; Multiaccess communication; Multicarrier code division multiple access; Multiple access interference; Power control;
Conference_Titel :
Signal Processing and Its Applications, 2003. Proceedings. Seventh International Symposium on
Print_ISBN :
0-7803-7946-2
DOI :
10.1109/ISSPA.2003.1224886