Title :
Linear Precoding Design in Multi-User Cognitive MIMO Systems with Cooperative Feedback
Author :
Gui, Xin ; Kang, Guixia ; Zhang, Ping
Author_Institution :
Key Lab. of Universal Wireless Commun. for the Minist. of Educ., Beijing Univ. of Posts & Telecommun., Beijing, China
fDate :
10/1/2012 12:00:00 AM
Abstract :
In this letter, we present a linear precoder design scheme for a cognitive (CR) multi-input multi-output (MIMO) system, where a secondary broadcast channel uses the same spectrum with multiple primary users (PUs). Considering both cooperative feedback from the PUs and local feedback from the secondary users (SUs) to the secondary transmitter (ST), the ST can obtain the quantized information regarding the direction of the channels. The proposed scheme is based on the minimum mean square error (MMSE) criteria and is robust to the channel uncertainties caused by quantization error. The derivation is given under two different levels of interference constraints respectively. Simulation results show the effectiveness of the proposed precoder design scheme.
Keywords :
MIMO communication; broadcast channels; cognitive radio; linear codes; mean square error methods; multi-access systems; precoding; quantisation (signal); radio spectrum management; radio transmitters; radiofrequency interference; CR MIMO system; MMSE criteria; PU; ST; SU; channel uncertainties; cognitive multiinput multioutput system; cooperative feedback; interference constraint; linear precoding design; local feedback; minimum mean square error; multiuser cognitive MIMO system; precoder design; primary user; quantization error; secondary broadcast channel; secondary transmitter; secondary user; spectrum; Interference constraints; MIMO; Noise; Quantization; Robustness; Vectors; Cognitive MIMO; cooperative feedback; minimum mean square error;
Journal_Title :
Communications Letters, IEEE
DOI :
10.1109/LCOMM.2012.081612.120623
