A Comparison of Scheduling Algorithms for Wireless Access plus X-Haul

We consider a centralized wireless architecture in which multiple cells are connected to a centralized unit via a shared x-haul. When computing a schedule for this architecture we must take into account capacity constraints on both the air interface access link and the x-haul. We evaluate three scheduling approaches that differ based on the degree of coupling between the air interface/x-haul and on whether queuing is allowed at the access link. It is known that we can optimize the geometric mean of throughput via a standard backpressure approach in which the air interface and x-haul scheduling is coupled by a queue at the access link. We demonstrate that with a joint scheduling approach we can obtain similar performance with zero queuing at the air interface (and hence zero delay).