Implementation of RSSI indexed look up table based AGC for improved dynamic range of DSSS based wireless rf transceivers

Abstract

The military wireless systems often have specific constraints such as achieving very good receiver sensitivity, very high tolerance to frequency shifts and best possible dynamic range. Direct spread spectrum (DSS) is the proven threat free technology in many militarized wireless systems, which will also gives the advantage of good receiver sensitivity because of spreading gain it offers. The RF dynamic range of the receiver is defined as the range of signal strength values for which receiver works without packet loss. Improving the RF dynamic range is one of the important challenges. Because of power variations, Doppler variation (or) any other wireless channel effect received signal power varies. In worst cases, the received signal power can vary with a dynamic range of 70 dB to 80 dB depending on the distance between a transmitter and a receiver. In this paper, we have implemented RSSI indexed Look Up Table (LUT) based approach of automatic gain control. The results show improvement in dynamic range with simplicity in implementation.