Net-eigen MAC: A new MIMO MAC solution for interference-oriented concurrent link communications

Interference-oriented concurrent link communications are designed as using each link's TX/RX beamforming vectors to null co-channel interference on existing links. Representative solutions in this area mainly include SPACEMAC and NullHoc protocols, which inherently rely on zero-forcing beamforming vectors and are not efficient in the sense that they only null the interference on existing links, but have little consideration for SNR maximization within the desired link. Motivated by this critical observation, in this paper we will present a new concurrent link solution, named as Net-Eigen MAC, which not only nulls the interference on existing links, but also maximizes the post-processing SNR within the desired link. Particularly, we implement above design objective via three sequential steps: (i) initial TX vector derivation that nulls interference on existing links; (ii) RX side whitening filter that transforms spatial colored interference into white Guassian noise; and (iii) TX/RX vector updating and eigen-value derivation for post-processing SNR maximization within the desired link. To demonstrate our proposed design, we first present a theoretical framework describing the mathematical principle of Net-Eigen MAC. Then we further propose a distributed handshaking process that implements the Net-Eigen MAC in a realistic way. Simulation results verify that our Net-Eigen MAC can guarantee each link's throughput to be no less than single link MAC's counterpart. And its ergodic link throughput is 28% higher than that of single link MAC or SPACEMAC.