ZTE Communications ›› 2012, Vol. 10 ›› Issue (1): 54-62.
Mehmood Awan1, Yannick Le Moullec1, Peter Koch1, and Fred Harris2
Mehmood Awan1, Yannick Le Moullec1, Peter Koch1, and Fred Harris2
摘要: In this paper, we describe resource-efficient hardware architectures for software-defined radio (SDR) front-ends. These architectures are made efficient by using a polyphase channelizer that performs arbitrary sample rate changes, frequency selection, and bandwidth control. We discuss area, time, and power optimization for field programmable gate array (FPGA) based architectures in anM -path polyphase filter bank with modifiedN -path polyphase filter. Such systems allow resampling by arbitrary ratios while simultaneously performing baseband aliasing from center frequencies at Nyquist zones that are not multiples of the output sample rate. A non-maximally decimated polyphase filter bank, where the number of data loads is not equal to the number ofM subfilters, processesM subfilters in a time period that is either less than or greater than theM data-load’s time period. We present a load-process architecture (LPA) and a runtime architecture (RA) (based on serial polyphase structure) which have different scheduling. In LPA,N subfilters are loaded, and thenM subfilters are processed at a clock rate that is a multiple of the input data rate. This is necessary to meet the output time constraint of the down-sampled data. In RA,M subfilters processes are efficiently scheduled withinN data-load time while simultaneously loadingN subfilters. This requires reduced clock rates compared with LPA, and potentially less power is consumed. A polyphase filter bank that uses different resampling factors for maximally decimated, under-decimated, over-decimated, and combined up- and down-sampled scenarios is used as a case study, and an analysis of area, time, and power for their FPGA architectures is given. For resource-optimized SDR front-ends, RA is superior for reducing operating clock rates and dynamic power consumption. RA is also superior for reducing area resources, except when indices are pre-stored in LUTs.