Concurrent channel access and estimation for scalable multiuser MIMO networking

This paper presents MIMO/CON, a PHY/MAC cross-layer design for multiuser MIMO wireless networks that delivers throughput scalable to many users. MIMO/CON supports concurrent channel access from uncoordinated and loosely synchronized users. This new capability allows a multi-antenna MIMO access point (AP) to fully realize its MIMO capacity gain. MIMO/CON draws insight from compressive sensing to carry out concurrent channel estimation. In the MAC layer, MIMO/CON boosts channel utilization by exploiting normal MAC layer retransmissions to recover otherwise undecodable packets in a collision. MIMO/CON has been implemented and validated on a 4×4 MIMO testbed with software-defined radios. In software simulations, MIMO/CON achieves a 210% improvement in MAC throughput over existing staggered access protocols in a 5-antenna AP scenario.