Static and Mobile Relay Selection with Chunk-Based Subcarrier Allocation in Uplink OFDMA Networks

Static and mobile relaying is often used to improve the user data rates in wireless communication networks, which would otherwise suffer due to large distances, interference, obstacles, and fading. In this paper, we propose two algorithms for static and mobile relay selection in order to minimize the total distance between a user and the base station. The most efficient algorithm (according to simulation results) relies on a KD-tree, which is a data structure used for fast retrieval of close points. We also propose a subcarrier allocation algorithm which divides the uplink channel subcarriers into a static chunk used for static relays, and dynamic chunk used for mobile relays and direct users. Dynamic allocation should be performed in real-time by the edge network, while static allocation can be perfomed periodically by the cloud network. Simulation results show that a greedy variation of the proposed allocation strategy is faster and more appropriate for the dynamic chunk, while the AP (assignment problem) variation gives slighty higher data rates and can be used for the static chunk.