Title :
Coding for asynchronous-CDMA systems
Author :
Wu, Y.W. ; Chang, S.C.
Author_Institution :
US Army CECOM RDEC, Warrenton, VA, USA
fDate :
29 Jun-4 Jul 1997
Abstract :
A coding scheme for asynchronous code-division multiple-access (CDMA) systems with finite delays is presented in this paper. All transmitted codewords are assumed to reach the receiver within finite delay of D digits. This coding scheme combines source encoding, synchronous-CDMA (S-CDMA) spreading sequences, and interleaving to support error-free asynchronous multiple-access communications. It can support at least m(log2m-2)/(2log2/3)+1log2 3 users and the lower bound of its maximum code rate approaches asymptotically to (1-D/T)(log2m)/(2log23) where m is the length of S-CDMA spreading sequence, and T>D+log(D+2)
Keywords :
code division multiple access; concatenated codes; delays; interleaved codes; source coding; spread spectrum communication; S-CDMA; asynchronous-CDMA systems; code-division multiple-access systems; codewords; coding; error-free asynchronous multiple-access communications; finite delays; interleaving; maximum code rate; receiver; source encoding; synchronous-CDMA spreading sequences; Added delay; Arithmetic; Concatenated codes; Decoding; Delay systems; Interleaved codes; Multiaccess communication; USA Councils;
Conference_Titel :
Information Theory. 1997. Proceedings., 1997 IEEE International Symposium on
Conference_Location :
Ulm
Print_ISBN :
0-7803-3956-8
DOI :
10.1109/ISIT.1997.613290
