Title :
Optimal space-time block codes for reduced complexity DS-CDMA decoders
Author :
Geng, Jifeng ; Mitra, Urbashi
Author_Institution :
Dept. of Electr. Eng. Syst., Univ. of Southern California, Los Angeles, CA, USA
Abstract :
Space-time coding promises greater insensitivity to wireless channel fading and improved channel capacity. In the current work, decoders based on the minimum mean squared error (MMSE) criterion are investigated. Two different MMSE-based decoders are developed based on knowledge about the residual error statistics. The performance of the decoders are evaluated in terms of achievable diversity levels for spread (so called "wideband" signaling) and non-spread ("narrowband") signaling as well as for single user and multi-user systems. The effects of multiple receive antennae is explicitly considered. Based on the pairwise symbol error rate, MMSE decoder optimized codes are found via exhaustive search. By evaluation of the union bound, it is seen that the MMSE decoder optimized codes offer good performance and ML decoder optimized space-time block codes generally maintain their good performance even when decoded through a MMSE decoder.
Keywords :
antenna arrays; block codes; channel capacity; code division multiple access; computational complexity; diversity reception; error statistics; fading channels; least mean squares methods; maximum likelihood decoding; multiuser channels; optimisation; receiving antennas; spread spectrum communication; ML decoder; MMSE decoder optimized codes; MMSE-based decoders; achievable diversity levels; channel capacity; exhaustive search; minimum mean squared error; multi-user systems; multiple receive antennas; narrowband signaling; nonspread signaling; optimal space-time block codes; pairwise symbol error rate; reduced complexity DS-CDMA decoders; residual error statistics; single user systems; space-time coding; spread signaling; union bound; wideband signaling; wireless channel fading; Block codes; Channel capacity; Decoding; Equalizers; Error analysis; Fading; Multiaccess communication; Pairwise error probability; Receiving antennas; Space time codes;
Conference_Titel :
Signals, Systems and Computers, 2001. Conference Record of the Thirty-Fifth Asilomar Conference on
Conference_Location :
Pacific Grove, CA, USA
Print_ISBN :
0-7803-7147-X
DOI :
10.1109/ACSSC.2001.987649
