Revisiting Optimal Link Activation and Minimum-Time Scheduling in Wireless Networks

Abstract: With the popularity of wireless communications in the last two decades, data traffic is exponentially increasing and requests high speed transmission. However, the resources, in particular, spectrum and energy, are limited. Therefore, network optimization with the objective of utilizing radio resource as efficiently as possible is crucial to the sustainable development of wireless communications.Link activation and scheduling are two classic problems of access coordination and resource allocation for multiple links that share a common channel. The problems originate from the broadcast nature of wireless media and are of significance in more complicated cross-layer optimization problems. Although there is a rich amount of literature, the problems remain challenging and are extended by novel setups incorporating new interference management technologies.In this thesis, we revisit these two fundamental problems with the main methods of mathematical modelling and applied optimization. The first two papers address the scheduling problem that amounts to emptying a given amount of data in minimum time. We derive theoretical insights including problem complexity, optimality conditions, as well as problem approximation and algorithmic framework, in general and for a class of networks with a particular structure. In the third paper, we incorporate cooperative transmission and interference cancellation with maximum link activation. Theoretical results and algorithm development are provided. Simulation study shows the new setup brings significant performance gain in comparison with the conventional approach.