Cooperative Beamforming for Multi-User Multi-Relay Cognitive Radio Networks Based on Second-Order Statistics of Channel State Information

Nabih Alaoui ； Vahid Meghdadi ； Jean-Pierre Cances

《International Journal of Communications》 2卷4期 (2013/12) Pp. 89-99

並列摘要

This paper has investigated linear beamforming techniques in relay networks with one source and multiple relays and destinations with the goal to determine the beamforming matrix so that the signal to noise plus interference ratio at the destination is maximized subject to different power constraints. Two power constraints were considered here: 1- a total (source and relay) power constraint and 2- individual relay power constraints. The key point of this paperwas tha only the second order statistics of channel state information (CSI) was proposed for use which is a more realistic scenario than the case where instantaneous CSI is assumed to be perfectly known at the relay place. It was considered that the source is equipped with multiple transmit antennas and hence it transmits a vector of several symbols at each time. Based on a former work of (J. Li, A. P. Petropulu and H. V. Poor 2011), this new optimization problem was solved and it was shown that despite some losses when compared to the case of zero forcing (ZF) precoding with perfect channel state information (CSI), the obtained results clearly show that second order statistics based beamforming algorithms are good candidates to reliably support multiple parallel data streams with SINR requirements in multiuser multirelay systems.

並列關鍵字

Beamforming ； Cooperative Networks ； Cognitive Radio Network ； Zero Forcing Beamforming ； Optimization under Power Constraints ； Second Order Statistics of Channel State Information