Adaptive resource management for a vague environment using cognitive radio

Adapting resource management, for vague environments, in wireless communication proved to be a measure point of research recently. In this paper we present a system that is capable of adapting some important resources (type of modulation, code rate and number of subcarriers) for blurred channel conditions. The system in this work is mainly designed for WiMAX, which proved to be one of the prominent technologies in providing Broadband Wireless Access (BWA) in metropolitan areas with a simpler installation and lower cost than the wired alternatives. The approach depends on using cognitive radio for decision making which uses fuzzy logic for reasoning. The cognitive engine controls the type of modulation, code rate and number of subcarriers in order to maintain a good system throughput without wasting available bandwidth. Fuzzy logic reasoning in the cognitive engine was chosen because it is well suited for situations of uncertainty, incompleteness and heterogeneity information, in the case of fast changing radio environments. The results showed that new combinations of modulation type, code rate and number of subcarriers should be considered in WiMAX since in most cases it outperforms the standard in error probability and spectral efficiency, especially in a fast changing radio environment.