On End-to-end Delay Minimization in Wireless Networks under the Physical Interference Model

The problem of scheduling transmission in single hop and multi-hop wireless networks with arbitrary topology under the physical interference model has been extensively studied. The focus has been on optimizing the efficiency of transmission parallelization through a minimum-frame-length schedule that meets a given set of traffic demands using the smallest number of time slots, each of which is associated with a set of compatible (according to the interference model) transmissions. This approach maximizes the resource reuse efficiency, but in general does not correspond to the best performance in terms of end-to-end packet delivery delay for multiple source-destination pairs, due to the inherent restriction of frame periodicity. In this paper, we study the problem of scheduling to minimize the end-to-end delay in wireless networks under the Signal to Interference plus Noise Ratio (SINR) constraints, and propose two schemes. The first scheme extends the minimum-frame-length approach with a phase of time slot ordering to account for the delay metric. The second scheme directly optimizes delay without the constraint of periodic framing. We propose novel mixed integer programming models for the two schemes and study their properties and complexity. Moreover, we present an efficient heuristic method that provides good quality solutions time-efficiently.