MIMO-assisted space-code-division multiple-access: linear detectors and performance over multipath fading channels

In this contribution, we propose and investigate a multiple-input-multiple-output space-division, code-division multiple-access (MIMO SCDMA) scheme. The main objective is to improve the capacity of the existing direct-sequence (DS)-CDMA systems, for example, for supporting an increased number of users, by deploying multiple transmit and receive antennas in the corresponding systems and by using some advanced transmission and detection algorithms. In the proposed MIMO SCDMA system, each user can be distinguished jointly by its spreading code signature and its unique channel impulse response (CIR) transfer function referred to as spatial signature. Hence, the number of users might be supported by the MIMO SCDMA system and the corresponding achievable performance are determined by the degrees of freedom provided by both the code signatures and the spatial signatures, as well as by how efficiently the degrees of freedom are exploited. Specifically, the number of users supported by the proposed MIMO SCDMA can be significantly higher than the number of chips per bit, owing to the employment of space-division. In this contribution, space-time spreading is employed for configuring the transmitted signals. Three types of low-complexity linear detectors, namely, correlation, decorrelating, and minimum mean-square error (MMSE) are considered for detecting the MIMO SCDMA signals. The bit-error rate performance of the MIMO SCDMA system associated with these linear detectors are evaluated by simulations, when assuming that the MIMO SCDMA signals are transmitted over multipath Rayleigh-fading channels. Our study and simulation results show that MIMO SCDMA assisted by multiuser detection is capable of facilitating joint space-time despreading, multipath combining, and receiver diversity combining, while simultaneously suppressing the multiuser interfering signals.

[1]  S. Haykin,et al.  Adaptive Filter Theory , 1986 .

[2]  Siavash M. Alamouti,et al.  A simple transmit diversity technique for wireless communications , 1998, IEEE J. Sel. Areas Commun..

[3]  Rick S. Blum,et al.  Guest editorial special issue on mimo wireless communications , 2003, IEEE Trans. Signal Process..

[4]  Teng Joon Lim,et al.  Space-time spreading codes for a multiuser MIMO system , 2002, Conference Record of the Thirty-Sixth Asilomar Conference on Signals, Systems and Computers, 2002..

[5]  Lie-Liang Yang,et al.  Minimum mean square error single-user detection of SDMA signals transmitted over Nakagami fading channels , 2004, 2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577).

[6]  Lie-Liang Yang,et al.  Performance of space-division multiple-access systems communicating over Nakagami fading channels , 2004, 2004 IEEE 59th Vehicular Technology Conference. VTC 2004-Spring (IEEE Cat. No.04CH37514).

[7]  J.E. Mazo,et al.  Digital communications , 1985, Proceedings of the IEEE.

[8]  Sergio Verdu,et al.  Multiuser Detection , 1998 .

[9]  A. Robert Calderbank,et al.  Space-time coding and signal processing for high data rate wireless communications , 2001, Wirel. Commun. Mob. Comput..

[10]  Emre Telatar,et al.  Capacity of Multi-antenna Gaussian Channels , 1999, Eur. Trans. Telecommun..

[11]  Simon Haykin,et al.  Adaptive filter theory (2nd ed.) , 1991 .

[12]  Andrea J. Goldsmith,et al.  Capacity limits of MIMO channels , 2003, IEEE J. Sel. Areas Commun..

[13]  Lajos Hanzo,et al.  Performance Comparison of FH/MC DS-CDMA with Single- and Multi-Carrier DS-CDMA , 2000 .

[14]  A. Robert Calderbank,et al.  Space-Time Codes for High Data Rate Wireless Communications : Performance criterion and Code Construction , 1998, IEEE Trans. Inf. Theory.

[15]  Chunming Qiao,et al.  Guest editorial high-performance electronic switches/routers for high-speed internet , 2003, IEEE J. Sel. Areas Commun..

[16]  Rodger E. Ziemer,et al.  Digital Communications and Spread Spectrum Systems , 1985 .

[17]  David Gesbert,et al.  From theory to practice: an overview of MIMO space-time coded wireless systems , 2003, IEEE J. Sel. Areas Commun..

[18]  Harry L. Van Trees,et al.  Optimum Array Processing , 2002 .

[19]  David W. Lewis,et al.  Matrix theory , 1991 .

[20]  Jack H. Winters,et al.  On the Capacity of Radio Communication Systems with Diversity in a Rayleigh Fading Environment , 1987, IEEE J. Sel. Areas Commun..

[21]  Thomas L. Marzetta,et al.  A transmitter diversity scheme for wideband CDMA systems based on space-time spreading , 2001, IEEE J. Sel. Areas Commun..

[22]  Helmut Bölcskei,et al.  An overview of MIMO communications - a key to gigabit wireless , 2004, Proceedings of the IEEE.

[23]  David Gesbert,et al.  Guest editorial: MIMO systems and applications. 1 , 2003, IEEE J. Sel. Areas Commun..

[24]  Jack M. Winters,et al.  Optimum Combining in Digital Mobile Radio with Cochannel Interference , 1984, IEEE Journal on Selected Areas in Communications.

[25]  Lie-Liang Yang,et al.  Performance of broadband multicarrier DS-CDMA using space-time spreading-assisted transmit diversity , 2005, IEEE Transactions on Wireless Communications.

[26]  João M. F. Xavier,et al.  Closed-form blind channel identification and source separation in SDMA systems through correlative coding , 1998, IEEE J. Sel. Areas Commun..

[27]  Thomas Kailath,et al.  Capacity improvement of base-station antenna arrays cellular CDMA , 1993, Proceedings of 27th Asilomar Conference on Signals, Systems and Computers.