Design of QSPM-MAC: Quasi-synchronous priority multi-channel MAC access protocol

Spectrum mobility poses a challenge to the medium access control (MAC) protocol design. This paper proposes a novel multi-channel MAC design, quasi-synchronous priority multi-channel (QSPM-MAC) protocol, for single transceiver device terminal of distributed cognitive radio networks (DCRN), presents a time frame structure consisting of spectrum sensing, channel access and data transmission, as well as the theoretical analysis framework. Depending on the different QoS requirements of different users, the proposed quasi-synchronous network access algorithm (QSNAA) euphemistically extends the contention time to increase the competitiveness of the cognitive users while solving the hidden terminal problem. The priority access policy based on super-slot commands the second position user (SPU) to abdicate to the primary position user (PPU), which reduces the collision probability. The results achieved from theoretical analysis and simulation show that the proposed protocol outperforms the existing protocol in many system performances.