An Efficient Coefficient Coding Scheme for Low Complexity Implementation of Pulse Shaping Filters in Gsm Receiver of a Software Radio

The IF processing block is by far the most computationally intensive part of wide-band receivers in software radios. From a signal processing point of view, digital filtering is the main task in IF processing. Infinite precision filters require complicated digital circuits due to coefficient multiplication. This paper presents an efficient method to implement pulse shaping filters for GSM receivers. We use an arithmetic scheme, known as pseudo floating-point (PFP) representation to encode the filter coefficients. By employing a span reduction technique, we show that the filters can be coded using 8-bit PFP with hardware complexity that is considerably lower than conventional 24-bit and 16-bit fixed-point filters. Simulation results show that the magnitude response of the filter coded in PFP meets the attenuation requirements of GSM specifications.