OBTAINING SUPERIOR PERFORMANCE FROM DUAL-CHANNEL RECEIVERS USING BEST-CHANNEL SELECTION
AbstractA Pre-Detection Maximal-Ratio Combiner (Pre-D MRC) provides optimal performance in the face of additive noise but sub-optimal and even potentially degraded performance in the face of other common channel impairments such as multipath. Using Data Quality Metric (DQM) information from the Pre-D MRC and its two input channels, a Best-Channel Selector (BCS) can correlate the three demodulated data streams and select the best available data on a bit-by-bit basis. Thus, the BCS can produce a single receiver output with optimal performance in additive noise and superior performance across all types of channel impairment – fulfilling the promise the Pre-D MRC cannot always keep. Further, since the BCS need only accommodate small and predictable latency differences between its inputs, its local performance may exceed that of an external source selector designed to handle seconds of delay between channels. This paper describes the BCS and presents performance results from several test scenarios.