Wireless NoC is an emerging paradigm to design high-bandwidth and energy-efficient communication backbones for massive multicore chips. The achievable performance of this type of on-chip interconnect infrastructure depends on the efficiency of the Media Access Control (MAC) protocol that arbitrates between the competing wireless nodes. In this work we propose the design of a distributed MAC protocol suitable for wireless NoC architectures. Compared to the widely used token passing scheme, a distributed MAC protocol improves scalability, provides better performance and lower overall energy dissipation. Depending on the traffic pattern, the proposed distributed MAC provides up to 23% improvement in energy delay product (EDP) when compared to the existing token passing scheme.