Reseach On Interference Suppression Technology Based On OFDM Communication System

As well as high rate wireless communication system, high throughput and high spectrum efficiency requirements, LTE(Long Term Evolution) and LTE-Advanced established by 3GPP chose the multiple access based on OFDM(Orthogonal Frequency Division Multiplexing) technology, OFDM become the core of the new generation of wireless communication system implementation technology. Subcarriers’ orthogonality ensures the user noninterference, but because of the limitation of frequency resources and same frequency network, inter-cell interference will seriously affect the system performance. In addition, under the compx electromagnetic environment, narrow-band interference will seriously destroy OFDM communication system. So the effective narrow-band interference suppression technology is a powerful guarantee of system to adapt to the disorderly electromagnetic environment. More importantly, the realization of improvement of the LTE system’s throughput and the service quality must use effective inter-cell interference suppression technology to meet the needs of the actual operation.On the basis of deep analysis of OFDM system, choose the appropriate parameter to build simulation model of the system, and study narrow-band interference signals in the influence of the change of power and bandwidth on the system; Put forward a new method to improve the interference suppression of OFDM system, by means of reconstruction suppressing jamming signal and feedback, improve the utilization of spectrum, and verify the effectiveness of the interference suppression system through the simulation. Build the cellular communication system simulation model based on OFDMA, and make the simulation for different reuse factor of frequency reuse scheme, research cell centre-edge radius percentage and bandwidth percentage for the influence of throughput and coverage. Simulate soft frequency reuse technology, and the center throughput influnced by the center and edge of transmission power ratio, choose the appropriate power ratio according to the actual situation. Put forward four different models in view of the sector of cellular system, through the switch between them in order to meet the actual needs of the business, thereby effectively restrain system inter-cell interference.Study and establish the downlink CoMP(Coordinated Multiple Points Transmission/Reception) model, the introduction of multiple users, as well as the choice of suitable area are the important factors that affect the user SINR gain, through collaboration and gain curve, such as collaborative SINR showed the geographical area of effective gain can be obtained. Soft frequency reuse is proposed on the basis of above the interference coordination and joint application of multi-point collaborative transmission technology. In between two base stations and base station coordination, combined with the soft frequency reuse model for fixed and adaptive simulation and analyze two kinds of combined transmission scheme, the results show that soft frequency reuse and CoMP can improve system performance, more effectively suppress inter-cell interference.