The Research Of Radio Resource Allocation In Algorithm In WiMAX Systems

With dramatically growing demands for wireless multimedia services, the limitied radio resource can not satisfy the quality of service (QoS), so the effective radio resource allocation becomes more and more important in the mobile communication systems. In this thesis, the radio resource allocation algorithms used in the uplink and downlink sub-frame have been researched respectively.Firstly, the thesis introduces the research target, research stutas and theoretical basis of the radio resource allocation. Then for the uplink initial access resource of WiMAX system, this thesis proposed an adaptive intial ranging resource allocation algorithm. It makes use of the number of initial ranging success users and the size of the initial ranging resource to estimate the number of initial ranging trigging users with Newton iterative. Through the variety trend of the ratio between the calculated number of the initial ranging triggering users and the actually allocated size of the initial ranging resource gained from the previous two frames, the size of initial ranging resource in the next frame can be adjust adaptively. In addition, the IEEE802.16 protocol proposes a closed-loop power control algorithm to reduce the power consumption of mobile terminals. This thesis carries out the simulations to verity its effectiveness.For the radio resource allocation in the downlink sub-frame, the algorithm proposed in this thesis adopts joint-optimization. It joints the QoS character of media access control sub-layer and the time-frequency fading character of the wireless channel to do the cross-layer radio resource allocation. With the limitied trammit power, the proposed algorithm does the schedule, sub-channel allocation and power allocation. Considering the limited size of traffic buffer in the realization, the schedule referes to the outgate rate of the traffic packets. In order to reduce the computational complexity, the sub-channel allocation and the power allocation are been conducetd separately. Under the criterion of rate adaptivity, the throughput of the system is been promoted through the effective radio resource allocation.