Resource Allocation And ICI Coordination In Cellular Networks

Orthogonal frequency division multiple access (OFDMA) has been written into thestandardized protocols of future wireless communication networks as a key techniquedue to its high spectral efficiency and its capability in combating frequency selectivefading. Adaptive resource allocation algorithm and inter-cell interference (ICI) are twomain factors affecting the performance of the cellular networks based on OFDMA.A suboptimal resource allocation algorithm based on a tradeoff factor (SRATF) isproposed in this paper, in order to solve the problem of sub-carrier and power allocationin OFDMA systems with heterogeneous services. Provided that the total transmittingpower is limited, it focuses on how to maximize the system throughput with therequirement of QoS from real time users and proportional fairness among non-real timeusers. Both of the adaptive resource allocation and adaptive modulation are combined inthe proposed algorithm, which results in an efficient tradeoff between the resourceusage of real time users and non-real time users. It is proved by the analysis in theorythat the running time has been reduced greatly with guaranteed overall systemthroughput and fairness between non-real time users. The results have been verified bycomputer simulations.This paper proposes a semi-static fractional frequency reuse (SFFR) schemeaiming at ICI coordination/avoidance, which is applied in an uplink cellular networkwith the users’ non-uniform distribution in each cell. It is supposed that there is noinformation exchange among the cells. Under any given distribution of cell load, theavailable frequency band is divided into four sub-bands with various ICI blockingcapabilities based on modeling and solving a localized weighted sum-rate maximizationproblem. Significantly, a method to select user weights representing different prioritiesof the user traffic is given. In addition, the user weights are updated according to cellload situation. For resource allocation, the schedulers efficiently allocate the frequencyresources to users under different ICI depending on the reported channel qualityinformation (CQI) and QoS requirements from them. Moreover, simple power control isused to further harness multiuser diversity. Simulations results show that the SFFRscheme decreases the cell capacity under some load distributions, but always has higheraverage edge user throughput compared with the enhanced fractional frequency reuse(EFFR) scheme.