Mozart: Orchestrating Collisions in Wireless Networks

Distributed packet scheduling in a wireless network is non-trivial due to lack of knowledge of which node has packets to transmit. This paper describes and evaluates Mozart, a new and practical approach that encourages collisions rather than trying to avoid them. Upon receiving multiple collided packets, the receiver carefully selects the retransmitters, so that all the packets can be recovered in the fewest number of slots. Our design enables the nodes to transmit without any backoffs during this recovery phase. To enable Mozart, we also propose a novel algorithm for estimating the Received Signal Strength (RSS) of a packet in presence of high interference. We implement Mozart on the USRP N210 radio and evaluate its performance on a USRP testbed. Our experiments show that Mozart’s throughput is up to 3.70x compared to IEEE 802.11. Using real world traces, we show that on average, Mozart provides a network throughput of 2.55x and 4.10x when compared to 802.11ec and 802.11, respectively.