Node architecture and MAC protocol for full duplex wireless and directional antennas

In this paper, we propose a novel node architecture introducing directional antennas into full duplex wireless (FDW) technology. In the proposed architecture, each element of switched-beam antenna is connected to a software switch for directional antenna selection. A node needs only one set of digital and analog cancellation circuits, which is almost the same circuit scale and complexity of the conventional omnidirectional FDW node. In addition, we propose a MAC protocol for the proposed node architecture with FDW and directional antennas for avoiding collisions and obtaining the advantages of both techniques. We evaluate the performance of the proposed protocol via computer simulations, and show that the proposed protocol can improve end-to-end throughput performance up to 114 percent in a line-type multihop network. Moreover, we extend the proposed MAC protocol for mitigating the performance degradation in two-way traffic in line-type multihop networks, and confirm its effectiveness. To the best of our knowledge, this is the first work that attempts to use directional antennas in FDW networks.