2011/05/30 by Chinmay S. Vaze, Vaze, Chinmay S., Mahesh K. Varanasi +1
Computer Science · Engineering · Mathematics · #Advanced MIMO Systems Optimization #Cooperative Communication and Network Coding #Wireless Communication Security Techniques #cs.IT #math.IT
paper · pdf · doi:10.48550/arxiv.1105.6033
Submitted to IEEE Trans. Information Theory, May 2011. A material in this paper will be presented in part at the IEEE Intern. Symp. Information Theory (ISIT), Aug. 2011
arxiv created 2011/05/30 · arxiv updated 2011/05/31
The two-user multi-input, multi-output (MIMO) interference and cognitive radio channels are studied under the assumption of no channel state information at the transmitter (CSIT) from the degrees of freedom (DoF) region perspective. With Mi and Ni denoting the number of antennas at transmitter i and receiver i respectively, the DoF regions of the MIMO interference channel were recently characterized by Huang et al., Zhu and Guo, and by the authors of this paper for all values of numbers of antennas except when min(M1,N1) > N2 > M2 (or min(M2,N2) > N1 > M1). This latter case was solved more recently by Zhu and Guo who provided a tight outer-bound. Here, a simpler and more widely applicable proof of that outer-bound is given based on the idea of interference localization. Using it, the DoF region is also established for the class of MIMO cognitive radio channels when min(M1+M2,N1) > N2 > M2 (with the second transmitter cognitive) -- the only class for which the inner and outer bounds previously obtained by the authors were not tight -- thereby completing the DoF region characterization of the general 2-user MIMO cognitive radio channel as well.