Coordinated Scheduling Based on Overload Indicator for LTE/LTE-A Uplink

This paper focuses on coordinated scheduling to combat uplink inter-cell interference for LTE/LTE-Advanced. In OFDM system, inter-cell interference is the dominant interference which limits system capacity, especially the performance of cell edge users. Meanwhile inter-cell interference in OFDM system has an inherent characteristic of interference fluctuation, which reduces the efficiency of channel dependent scheduling and the accuracy of MCS selection. In conventional inter-cell interference coordination methods, such as path-loss based coordinated scheduling, fractional frequency reuse and OI (overload indicator) based inter-cell power control, either the estimation of the interference is not accurate or the problem of interference fluctuation is not solved. To combat these problems, we propose a coordinated scheduling method by utilizing multiple OI thresholds. In our method, different OI thresholds are previously determined on different resource blocks, having a complementary pattern among neighbor cells. Based on the exchanged OI information among neighbor cells, one user can be scheduled to an appropriate resource block, on which the neighbor cells can endure inter-cell interference caused by this user. So high interference generated users and high interference endurable users are scheduled on same resource block, resulting in more accurate inter-cell interference estimation and reduced interference fluctuation.