COPA: cooperative power allocation for interfering wireless networks

As 802.11 wireless networks proliferate, interference becomes increasingly severe, particularly in dense, urban environments. These networks are usually operated by different users (e.g., tenants in apartments). In this paper, we develop techniques for mitigating interference between such loosely cooperating 802.11 MIMO APs and clients, which do not share a high-speed wired backplane or central controller. We propose CoOperative Power Allocation (COPA), an approach to concurrent wireless medium access that combines fine-grained, per-subcarrier power allocation, nulling, and multi-stream transmission to claim capacity that status-quo approaches cannot. Jointly turning these knobs allows COPA to allocate subcarriers to senders partially, rather than all-or-nothing, and to embrace a measure of interference when doing so increases capacity.