Adjacent Channel Interference Mitigation Schemes for Software Defined Radio Receiver July 2008 Anas Bin

Wireless communication technology such as cellular and wireless local area network (WLAN) systems have grown rapidly and generated various competing transmission formats. In the need of seamless communication across incompatible radio standards, software defined radio (SDR) concept has received much attention among researchers working in mobile and personal wireless communications. SDR is a technology that allows a single terminal to support various kinds of wireless systems and services such as mobile systems and WLANs by changing software to reconfigure the wireless terminal. In order to realize a SDR receiver, flexible receiver architecture with wideband signal receiving capability is required. However, if the receiving bandwidth is wider, the received signal components may cause interference to each other. In this study, the signal processing methods to combat the adjacent channel interference (ACI) problems in the SDR receivers are investigated and discussed. In this dissertation, we use 2 approaches to realize the flexible receiver for SDR; 1. Low-IF signal mixing downconversion receiver architecture 2. RF sampling receiver architecture In the low-IF receiver, received radio frequency (RF) signal is mixed down to a nonzero low or moderate intermediate frequency (IF). The low-IF receiver is superior to conventional superheterodyne receiver as the architecture does not require external filter. The low-IF receiver does not suffer much from its non-idealities, such as DC-offset and 1/f noise problems in direct-conversion receiver (DCR). In the RF sampling receiver architecture, the received signal is sampled at a RF and is processed