Open Access

Space-Time Coded MC-CDMA: Blind Channel Estimation, Identifiability, and Receiver Design

EURASIP Journal on Advances in Signal Processing20032002:480905

DOI: 10.1155/S1110865702209075

Received: 8 June 2002

Published: 2 January 2003

Abstract

Integrating the strengths of multicarrier (MC) modulation and code division multiple access (CDMA), MC-CDMA systems are of great interest for future broadband transmissions. This paper considers the problem of channel identification and signal combining/detection schemes for MC-CDMA systems equipped with multiple transmit antennas and space-time (ST) coding. In particular, a subspace based blind channel identification algorithm is presented. Identifiability conditions are examined and specified which guarantee unique and perfect (up to a scalar) channel estimation when knowledge of the noise subspace is available. Several popular single-user based signal combining schemes, namely the maximum ratio combining (MRC) and the equal gain combining (EGC), which are often utilized in conventional single-transmit-antenna based MC-CDMA systems, are extended to the current ST-coded MC-CDMA (STC-MC-CDMA) system to perform joint combining and decoding. In addition, a linear multiuser minimum mean-squared error (MMSE) detection scheme is also presented, which is shown to outperform the MRC and EGC at some increased computational complexity. Numerical examples are presented to evaluate and compare the proposed channel identification and signal detection/combining techniques.

Keywords

MC-CDMA OFDM space-time coding blind channel identification identifiability multiuser detection

Authors’ Affiliations

(1)
Department of Electrical and Computer Engineering, Villanova University
(2)
Department of Electrical and Computer Engineering, Stevens Institute of Technology

Copyright

© Sun and Li 2002