Cog-PRMA protocol for CR users sharing a common channel with TDMA primary users

To enable secondary transmissions in cognitive radio (CR) networks, the medium access control (MAC) protocol design for CR networks is an important but challenging issue. In this paper, we propose a cognitive packet reservation multiple access (Cog-PRMA) protocol for the CR/secondary users (SUs) sharing a common channel with time division multiple access (TDMA) primary users (PUs). This Cog-PRMA protocol not only achieves the goal of supporting secondary packet transmissions without interfering the PUs´ transmissions, but also takes advantage of PRMA to improve the CR network bandwidth efficiency. In this paper, the Cog-PRMA protocol and frame structure are fully described, and theoretical network throughput for the CR networks is derived using the speech model and two dimensional Markov chain in this paper. Simulation results show that effective secondary communication is achieved and there are noticeable increases in the total network throughput (primary plus secondary).