We design a cross-layer approach to optimize the cooperative use of multi-packet reception and network coding, in order to relieve congestion. We construct a model for the behavior of the 802.11 MAC and apply it to several key canonical topology components and their extensions to any number of nodes. The results obtained from this model match the available experimental results, which are for routing and opportunistic network coding, with fidelity. Using this model, we show that fairness allocation by the MAC can seriously impact performance; hence, we devise a new MAC that not only substantially improves throughput, but also provides fairness to flows of information rather than to nodes. We show that the cooperation between network coding, multi-packet reception, and our new MAC achieves super-additive gains of up to 6.3 times that of routing alone while using the standard 802. 11 MAC. Furthermore, we show that these gains depend on the symmetry of traffic across each bottleneck. Finally, we extend the model to analyze the asymptotic and throughput behavior of our new MAC as the number of nodes increases and the MPR capability is limited to a subset of nodes within the network respectively.