Fair queueing for mmWave WMN backhaul

Static Wireless Mesh Networks (WMN) based on high capacity pencil-beam millimeter wave (mmWave) links offer an attractive solution for small cell backhauling in 5G networks. However, the delay targets in 5G are such that it is quite challenging to develop adequate link scheduling and routing mechanisms especially for a system composed of backhaul nodes with a single TDD radio. We have proposed earlier a scheme that is based on cyclic semipermanent link schedules and multiple spanning tree based multipath routing. This scheme enables multihop backhaul connections with low delays and fast fault recovery. However, so far this scheme has been analyzed only by using end-to-end delay estimates based solely on link schedules. The potential effects of different queueing disciplines have not been studied in detail. In this paper, we will show how common output queueing systems can have a harmful interplay with the cyclic link schedules that contradicts our primary path optimization targets. We will also suggest a few simple modifications to existing queueing solutions that resolve these problems at WMN node level.