Embracing Distributed MIMO in Wireless Mesh Networks

This paper proposes a novel routing protocol, DM⁺, to achieve distributed spatial multiplexing gain in wireless mesh networks. It lets multiple nodes simultaneously send and receive different streams over each hop. To realize this goal, we propose an optimization framework that jointly optimizes spatial multiplexing, routing, and rate limits while taking into account wireless interference. We further design and implement a practical routing protocol that (i) enforces the optimized multiplexed routes, (ii) synchronizes transmissions from different senders, (iii) encodes and decodes analog signals to support simultaneous transmissions, and (iv) compensates for the frequency offset incurred over a multihop path. Using QualNet simulation and USRP implementation, we show it significantly out-performs state-of-the-art shortest path routing and opportunistic routing protocols. To our knowledge, this is the first routing protocol and prototype that achieves distributed spatial multiplexing in a real multihop network.