Interference mitigation between COMPASS and TD-LTE downlink by subband power reallocation

With the development of Time Division Long Term Evolution (TD-LTE) system, the TD-LTE base station´s density is increasing rapidly. The working spectrum of Compass Navigation Satellite System (COMPASS, also called BeiDou Navigation Satellite System) is adjacent to TD-LTE system. Because the signal received by COMPASS Equipment (CE) is very weak, large frequency isolation between TD-LTE downlink and COMPASS is necessary to avoid inter-system interference, which causes severe spectrum waste. There is still no effective solution to fix this problem. In this paper, we propose an algorithm to change the subbands power allocation of TD-LTE to reduce the interference in COMPASS system caused by TD-LTE downlink, meanwhile reduce the necessary frequency isolation between the two systems. In this algorithm, it is assumed that BSs receive the position information and interference information of CE. The algorithm decreases the interference received by CE to an acceptable level by adjusting the transmit power of nearby BSs´ subbands within preset scope, thus, reduce the necessary frequency isolation. Finally, a system level simulation is conducted to investigate the performance of IEA-SPR.