Enabling multi-hop wireless mesh networks with multi-input multi-output (MIMO) functionality boosts network throughput by transmitting over multiple orthogonalspatial channels (spatial multiplexing) and by performing interference cancellation,to allow links within interference range to be concurrently active. Furthermore,if the channel is in a deep fade, then multiple antenna elements at thetransmitter and/or receiver can be used to transmit a single stream, thereby improvingsignal quality (diversity gain).However, there is a fundamental trade-off between boosting individual link performanceand reducing interference, which must be modeled in the process of optimizingnetwork throughput. This is called the diversity-multiplexing-interference suppressiontrade-off. Optimizing network throughput therefore, requires optimizing the trade-offbetween the amounts of diversity employed on each link, the number of streams multiplexedon each link and the number of interfering links allowed to be simultaneouslyactive in the network.We present a set of efficient heuristics for one-shot link scheduling and streamallocation that approximately solve the problem of optimizing network throughputin a single time slot. We identify the fundamental problem of verifying the feasibilityof a given stream allocation. The problems of general link scheduling and streamallocation are very closely related to the problem of verifying feasibility.We present a set of efficient heuristic feasibility tests which can be easily incorporatedinto practical scheduling schemes. We show for some special MIMO networkscenarios that feasibility is of polynomial complexity. However, we conjecture that ingeneral, this problem, which is a variation of Boolean Satisablility, is NP-Complete.
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