Key Technology Of Interference Control In Wireless Communication Networks

With the rapid growth of China’s economy various wireless communication systems (LTE, MANET, WiFi, WiMAX, etc.) have been developed, in which growing rate requirements and mobile objectives for wireless communication systems caused the coexistence of multiple wireless access technologies. As a result, more efficient interference control technologies are needed in both academics and industry fields.This paper is supposed to research the key technologies in Hetnet and VANETs.3GPP has started the standardization process of heterogeneous network technologies in LTE-Advanced system. The traditional interference control technologies can’t achieve desired performance because of the new interference environment of heterogeneous networks and the resource competition caused by the coexistence of different types of nodes. It is necessary to develop new inter-cell interference coordination technologies to ensure the network stability and improve network performance. Meanwhile, with the popularity of the vehicle, traffic safety has increasingly become one of the world’s most concerns. The technologies to reduce the interference in the vehicle ad-hoc networks and the probability of accidents need to be developed.In the Hetnet in LTE-A system, the interference coordination technologies is achieved by taking advantage of resource management in the network layer. In VANETs, however, we focus on the access mechanisms of MAC layer. In this paper, the research results obtained are as follows:For Hetnet, firstly we summarize the existing eICIC technology in LTE-A heterogeneous network. After the theoretical analysis, simulations are processed to evaluate the performance of Almost Blank Subframe and Reduced Power Subframe. The simulation results, which include the Macro user throughput and Pico user throughput in downlink, prove that the system capability will be improved by the coordination of Macro and Picos.For VANETs, the channel access methods are researched to control the channel interference. In this paper, an adaptive hybrid MAC scheme is proposed for VANETs, in which "hybrid sub-frame" is designed considering of channel access delay and packet drop probability. Both CSMA/CA and STDMA are used in the hybrid scheme and the splitting percent is supposed to be adjusted according to the traffic load in the system, in which way the packet drop probability and the channel access delay can be reduced because of the controlled interference.