Scheduling vs. pseudo-scheduling models in IEEE 802.16j wireless relay networks

Given the relatively low costs associated with its deployment and its capacity to deliver last mile wireless broadband access, WiMAX and LTE are the current technologies of choice to effectively meet the increasing demand for high bandwidth services and applications. In the literature, several pseudo scheduling algorithms, which are very often time-independent, have been proposed to optimize the scheduling horizon without taking care of the sequencing of packets within the scheduling period. In this paper, we develop an optimization model having in mind to perform "true" scheduling, not only optimizing the scheduling horizon but taking into account the allocation of resources over a given time window. We propose a two-step solution scheme. The first step relies on a model, which chooses among a set of possible configurations (a set of transmitting links over a predetermined period of time slots) with end-to-end transmissions. The second step consists in a time ordering of those configurations, in order to complete the scheduling process. In our experiments, we compare our solution scheme with one of those so-called "scheduling" in order to investigate how the throughput varies depending on whether we use pseudo=scheduling vs. "true" scheduling. The results show how explicitly considering nodal buffers can make a meaningful difference on the forms of scheduling, depending on the assumptions on the buffer sizes.