Multi-Blocker-Tolerant Passive MIMO Receivers

Wireless connections worldwide is slowly moving away from being noise limited to interference-limited communications. Newer generation radios use MIMO techniques to increase throughput by exploiting multipath signals from all directions. Unfortunately, this means that a single co-channel blocker from any direction can jam all the antennas. Prior techniques attempted to solve the co-channel blocker problem by providing nulls in a few directions using active circuits. The proposed architecture is based on providing both spectral and spatial filtering using all passive techniques, which results in superior co-channel blocker resistance. Linear filtering techniques that have an inverse can be used to provide RF beamforming combined with a baseband inverse without losing any of the multipath information. The M-antenna architecture can handle blockers from M-1 spatial directions. Additionally, the data throughput for the proposed design drops gracefully as the number of jammers increase. We provide measurement results from a 4-antenna prototype design.