The Evaluation Of RF Channel Impairments And Co-channel Interfrence Over Rician Fading Channel

Abstract

The mobile network system has evolved into its 4th generation and the demand of faster data rate, higher network coverage and reliable communication has never stop. In order to have more bandwidth and reduce power consumption, more and more new transmitting and receiving devices has been developed to achieve the goal. However, during this evolution, the performance of the system is suffering from effects by the radio-frequency (RF) circuit design, which produces DC offset, in-phase and quadrature (IQ) imbalance and phase noise. Also, in cellular mobile communication system, signals from different sources can be using the same frequency spectrum, and those signals will distort each other, producing co-channel interference (CCI) in the system.In this thesis, the influences by each one of these interference in the Rician fading channel wireless system with QPSK modulation have been evaluated. Simulations are designed to find out the dB loss between the original system that has not interfered and the system that are affected by channel impairments and channel interference. The simulation results show that MIMO system does not suffer much from that the DC offset but the SISO3system is significantly influenced. The IQ imbalance and phase noise have very little impact on both SISO and MIMO wireless systems. However, the CCI could make as larege as 6.6 dB to SISO sytem and around 2.3 dB to MIMO system. The combined interference, which means adding all these interference factors to the system at the same time, causes large dB loss to MIMO and SISO system, particularly when CCI has small SIR value. In most cases, MIMO system has less dB loss than SISO system when experiencing channel impairments and channel interference.