Investigation Of Power Control And Resource Allocation In Ieee802.16e

IEEE802.16standard is known as basic solution for local and metropolitan areanetwork WiMAX. IEEE802.16e is a reversion and consolidates material from802.16for operational frequencies from2-6GHz supporting the air interface for fixed andmobile broadband wireless access system, high data rates service so that users canswitch and roaming among base stations, subscriber station move with vehicularspeed, which become an important milestone in the history of WiMAX technologydevelopment. WiMAX private wireless network widely serves the field of emergencycommunications of the electricity, petroleum, water conservancy, civil airportemergency communications services.In this paper, we investigate the power control and resource allocation inIEEE802.16e wireless network. These advanced algorithms and methods areconsidered in detailed.Firstly, in order to implement the closed loop power control in IEEE802.16e,ranging mechanism is utilized to obtain the power adjustment parameters. Thegeneration, transmission and testing principle of ranging code are analyzed in theIEEE802.16e standard. Considering the influence of threshold on the detection,simulations have been undertaken to select the appropriate threshold by detection rate,omission inspection rate and false alarm rate. The proposed implementation processof ranging code detection, power detection and timing delay are accomplished by DSPto guarantee the feasibility, and it is utilized in IEEE802.16e base station.Then, co-channel interference (CCI) model in IEEE802.16e uplink network openloop power control is presented. The outage probability of SINR with respect topower control is derived based on the CCI model. Hard/soft limiting combiningalgorithms are proposed to reduce interference. Simulation results show that theproposed combining algorithms can suppress the co-channel interference and reducethe outage probability of SINR, such that the power control performance ofIEEE802.16e uplink can be improved.Furthermore, considering the IEEE802.16e downlink power control is powerallocation actually, for the multi-cell IEEE802.16e network, the suitable CCI model isutilized firstly to solve resource allocation problem which is subject to power andbandwidth constraint. Then, the joint bandwidth and power allocation scheme isproposed based on different resource allocation strategies which are the maximizationof the sum capacity of all users, the maximization of the worst user capacity and theminimization of the total power consumption of all users respectively which can betransformed into convex optimization question. Simulations results show that the proposed scheme can increase the system capacity and reduce power consumptioncompared with the convention resource allocation method.Finally, the weighted sum rate maximization (WSRM) power allocation ismodeled based on fairness among users in multi-cell IEEE802.16e downlink network,and solving the NP-hard by transforming the model into second-order coneprogramming. The results show that the WSRM based downlink power allocation canincrease the spectrum capacity and guarantee the fairness among users compared withthe conventional average sum rate maximization.