Cross-Layer Adaptive Resource Allocation Algorithm For Wireless Communications Networks

In this paper, a cross-layer adaptive resource allocation (XARA) algorithm for channel division based systems, such as OFDMA, is proposed. XARA design is based on a PHY-MAC cross-layer approach which yields better channel utilization compared to separate PHY or MAC designs. XARA uses a joint power and channel allocation algorithm to determine both the channel assignment and the transmission power for each user in order to maximize the overall system capacity. Through an iterative algorithm, XARA enhances the channel utilization by taking into account the demands of the users so as to assign the minimum number of time slots needed to fulfill the requirements of each user. The saved time slots are reported to the scheduling and admission control functions of the MAC layer in order to either allow more users to enter the network or to allow the current users to request more quality of service "QoS" sessions. The proposed algorithm can fit in different wireless systems such as WIMAX and LTE. The algorithm is also flexible enough to accommodate the dynamic nature of the spectrum in the case of cognitive radio networks and considers the power constraints associated with such networks.