Interference cancelling receiver for range extended reception in TDMA cellular systems
K. Kim, Gordon L. Stüber · 2003
An interference rejection combining (IRC) receiver with a highly selective antenna array is proposed for GSM/EDGE cellular systems to mitigate the effect of uncorrelated cochannel interference (CCI) and provide extended range reception. IRC is used to combat cochannel interference by maximizing the received signal-to-interference-plus-noise ratio (SINR). When multiple antenna arrays, each having a narrow angle of reception, are aligned in different directions, the number of incoming rays from both the desired and and interfering signals at each antenna is limited, and the cochannel interferences at different antennas are uncorrelated and the average carrier-to-interference ratios (CIRs) seen at each antenna array are not equal. An IRC delayed decision feedback sequence estimation (IRC-DDFSE) receiver is proposed and evaluated for a variety of cochannel interference environments. Also, the log-likelihood ratio (LLR) of each bit is generated from the IRC-DDFSE receiver to be used as an input parameter for an adaptive antenna array beam steering function. The BER performance and the reliability of the softout of the receiver is evaluated by computer simulation for line-of-sight Rician fading channels.