Title :
A new look at digital orthogonal transmultiplexers for CDMA communications
Author :
Akansu, Ali N. ; Tazebay, M.V. ; Haddad, Richard A.
Author_Institution :
Dept. of Electr. & Comput. Eng., New Jersey Inst. of Technol., Newark, NJ, USA
fDate :
1/1/1997 12:00:00 AM
Abstract :
Orthogonal transmultiplexers have been successfully utilized for multiuser communications. They are of the FDMA type in their most common version. The transmultiplexers using frequency selective PR-QMFs as their user codes were reported in the literature. This approach conflicts with the requirements of a CDMA communications system. We introduce novel spread spectrum PR-QMF codes, wherein the orthogonality is distributed over both time and frequency domains. It is shown that the proposed multivalued spread spectrum PR-QMF codes with minimized auto and cross-correlation properties outperform the conventional binary Gold codes in CDMA communication scenarios considered in the article
Keywords :
FIR filters; band-pass filters; binary sequences; code division multiple access; convolutional codes; correlation methods; digital radio; filtering theory; quadrature mirror filters; signal reconstruction; spread spectrum communication; telecommunication channels; transmultiplexing; CDMA communications; FDMA; autocorrelation properties; conventional binary Gold codes; cross-correlation properties; digital orthogonal transmultiplexers; frequency domain; multiuser communications; multivalued spread spectrum PR-QMF codes; perfect reconstruction FIR QMF banks; spread spectrum communications; time domain; user codes; Communication systems; Delay; Filter bank; Finite impulse response filter; Frequency division multiaccess; Frequency division multiplexing; Frequency domain analysis; Gold; Multiaccess communication; Spread spectrum communication;
Journal_Title :
Signal Processing, IEEE Transactions on
