Delay properties in non-orthogonal spectrum sharing with adaptively rate controlled selfish dynamic spectrum control

This paper discusses message delay properties of an autonomous selfish dynamic spectrum control (S-DSC) in comparison to a carrier sense multiple access with collision avoidance (CSMA/CA) for the cases that S-DSC is applied to future machine to machine (M2M) wireless networks in which lower latency rather than higher throughput is required. To achieve this requirement while satisfying a certain level of spectral efficiency, selfish acquisition of spectrum using DSC is proposed in which interference is statistically controlled to an acceptable level by random selection of spectrum in the DSC process. Specifically, in the S-DSC, each node selects a certain amount of spectrum having higher channel gain and the transmitted spectrum is mapped onto the selected spectrum. Because channel gain in a system band for each user is different and varies independent to each other, interference becomes sparse in the selected spectrum and link for each user becomes less sensitive to mutual interference even if each node transmit signals without mutual coordination. Computer simulations confirm that the proposed scheme can share a system band with the aid of S-DSC and achieve shorter delay time in comparison to CSMA/CA employed system.