Adaptive initial ranging resource allocation algorithm in IEEE802.16 system

In IEEE802.16 system, the initial ranging uses the random access mode. The standards [1] [2] define the size of initial ranging resource(IRR-size) as a fixed and large value, but the large size of ranging resource can cause the waste. To solve the above problem, this paper proposes an adaptive initial ranging resource allocation algorithm. It makes use of the trend of the ratio between the calculated number of the initial ranging triggering users(IRTU-num) and the actually allocated size of the initial ranging resource(AIRR-size) which are gained from the previous two frames to adaptively adjusts IRR-size in the next frame. By comparing with the fixed allocation algorithm, the simulation results verify the proposed algorithm can significantly improve the system performances at the aspects of the average success rate per ranging slot(AS), the average occupation rate per ranging slot(AO) and average access delay(AD). The simulation results math the theory analysis very well. The proposed algorithm can be put into practical application.