A Pseudo Random Sequence Based Multichannel MAC Protocol for Directional Ad Hoc Networks

In directional ad hoc networks, the character of directional transmission and directional reception of the links makes it difficult to let one directional link aware of the other concurrent transmission links, so that the collision probability of the concurrent transmission links need to be reduced. In this paper, a pseudo random sequence (PRS) based multi-channel multiple access control (MAC) protocol is proposed to reduce the collision probability of the concurrent transmission links. The proposed PRS MAC protocol is based on the time division multiple access (TDMA) frame structures. After the neighbour discovering sub-frame, the proposed PRS MAC protocol works in the reservation sub-frame, and in each time slot it works in a three-way handshake method to reserve the data slots in the data transmission sub-frame. On one hand, with the introduction of multiple channels, the concurrent transmission links can be distributed to different channels such that the collision probability of each channel can be reduced. On the other hand, with the introduction of the pseudo random sequence, each of the concurrent transmission links may take different PRS such that the collisions of the concurrent transmission links are randomized. Simulation results show that the proposed PRS MAC protocol outperforms the existing DTRA protocol in terms of lower collision probability and higher aggregated throughput.