Dynamic Interference-Avoiding MIMO Links

We address the problem of dynamically optimizing arbitrary multiple-input multiple-output (MIMO) wireless links that may or may not be directional to avoid interference over a fixed frequency band. The optimization is, therefore, applicable to near-field machine-to-machine communications. Specifically, we aim to determine the transmitter beam weight vector and pulse code sequence that maximize the signal-to-interference-plus-noise ratio (SINR) at the output of the joint maximum-SINR space-time receiver filter. We propose a novel and simple model-based solution that we call space-first-time-next waveform optimization where we optimize first the transmit weight vector (space) and then the pulse code sequence (time). We derive the solution formally and evaluate its performance through extensive simulation studies considering varying waveform code length, near-field/far-field conditions, and spread-spectrum/non-spread-spectrum interference. The studies demonstrate the effectiveness of the proposed method and its remarkable interference avoidance capability in dense interference scenarios compared to static conventionally designed MIMO links.