A Simple and Efficient User-Scheduling Strategy for RUB-Based Multiuser MIMO Systems and Its Sum-Rate Analysis

We present a user-scheduling scheme for multiuser multiple-input-multiple-output (MIMO) systems with random unitary beamforming (RUB) in this paper. The new scheme, which is termed as adaptive beam activation based on the conditional best beam index feedback (ABA-CBBI), requires low average feedback load by imposing a feedback threshold on the users' signal-to-interference-plus-noise ratio (SINR) and suffers less multiuser interference by only activating those beams requested by at least one user. We derive the exact analytical expression for the sum-rate capacity of the resulting multiuser MIMO systems, based on which we examine the optimal selection of the feedback threshold in terms of sum-rate maximization. We demonstrate through selected numerical examples that the proposed ABA-CBBI scheme with optimal thresholds can achieve better sum-rate performance than existing schemes over high-signal-to-noise-ratio (SNR) regions.

[1]  Babak Hassibi,et al.  On the capacity of MIMO broadcast channels with partial side information , 2005, IEEE Transactions on Information Theory.

[2]  Mohamed-Slim Alouini,et al.  Adaptive Modulation with Diversity Combining Based on Output-Threshold MRC , 2007, IEEE Transactions on Wireless Communications.

[3]  Mohamed-Slim Alouini,et al.  How much feedback is multi-user diversity really worth? , 2004, 2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577).

[4]  Andrea J. Goldsmith,et al.  Duality, achievable rates, and sum-rate capacity of Gaussian MIMO broadcast channels , 2003, IEEE Trans. Inf. Theory.

[5]  Yeheskel Bar-Ness,et al.  Scaling Law of the Sum-Rate for Multi-Antenna Broadcast Channels with Deterministic or Selective Binary Feedback , 2006, 2006 IEEE Information Theory Workshop - ITW '06 Punta del Este.

[6]  David Tse,et al.  Sum capacity of the vector Gaussian broadcast channel and uplink-downlink duality , 2003, IEEE Trans. Inf. Theory.

[7]  Max H. M. Costa,et al.  Writing on dirty paper , 1983, IEEE Trans. Inf. Theory.

[8]  Thomas L. Marzetta,et al.  Multiple-antennas and isotropically random unitary inputs: The received signal density in closed form , 2002, IEEE Trans. Inf. Theory.

[9]  Chan-Soo Hwang,et al.  A random beamforming technique in MIMO systems exploiting multiuser diversity , 2003, IEEE International Conference on Communications, 2003. ICC '03..

[10]  Wei Yu,et al.  The optimality of beamforming in uplink multiuser wireless systems , 2004, IEEE Transactions on Wireless Communications.

[11]  Nihar Jindal,et al.  MIMO broadcast channels with finite rate feedback , 2006, GLOBECOM '05. IEEE Global Telecommunications Conference, 2005..

[12]  Young-Chai Ko,et al.  Exact Sum-Rate Analysis of MIMO Broadcast Channels with Random Unitary Beamforming Based on Quantized SINR Feedback , 2008, 2008 IEEE International Conference on Communications.

[13]  Young-Chai Ko,et al.  Sum-Rate Analysis of MIMO Broadcast Channel with Random Unitary Beamforming , 2008, 2008 IEEE Wireless Communications and Networking Conference.

[14]  T. Kirubarajan,et al.  Random unitary beamforming with partial feedback for multi-antenna downlink transmission using multiuser diversity , 2005, 2005 IEEE 61st Vehicular Technology Conference.

[15]  Andrea J. Goldsmith,et al.  On the optimality of multiantenna broadcast scheduling using zero-forcing beamforming , 2006, IEEE Journal on Selected Areas in Communications.