Method and apparatus for symbol alignment in diversity signal reception

Abstract

Methods and apparatus taught herein provide for symbol alignment between diversity signals in a communication receiver. For example, in one embodiment, a method of symbol aligning diversity signals in a communication receiver comprises generating diversity sample sets for a received signal and hypothesizing two or more relative symbol alignments for the diversity sample sets. The method further includes jointly determining a preferred relative symbol alignment and a preferred synchronization position for the diversity sample sets by evaluating a function that is dependent on relative symbol alignment and synchronization position according to the hypothesized relative symbol alignments and a number of candidate synchronization positions. In one embodiment, a burst-type communication receiver uses Single-Antenna-Interference-Cancellation (SAIC) processing, and over-samples the received signal to obtain the diversity sample sets as sub-channels of the received signal. A diversity processor in the receiver jointly determines the best relative symbol alignment and synchronization position.

Description

technical field [0001] The present invention relates generally to communication receivers, and in particular to symbol alignment in diversity-based communication receivers. Background technique [0002] Diversity receivers exploit transmit redundancy to achieve receive performance improvements. For example, so-called multi-branch receivers typically include two or more antennas, each providing an antenna-specific version of the same received signal. Assuming that for a certain minimum spatial separation of the antennas, the received signal typically exhibits uncorrelated fading behavior across the antennas, thus each antenna provides a different diversity signal for processing. [0003] However, multi-antenna designs carry the disadvantage of their inherent cost. Furthermore, as a practical matter, it is quite a challenge to adapt even the highest performance antennas to small portable communication devices. Few designers would welcome the added burden of finding space fo...

AI Technical Summary

Problems solved by technology

However, a typical assumption, especially in the case of oversampling receivers, is that diversity signals are naturally mutually aligned symbols

However, delay variations in the propagation channel, sampling phase mismatches in anti-aliasing filters, analog-to-digital converter and decimation filter mismatches, etc., can cause misalignment of symbols between diversity signals

Therefore, the assumption of natural symbol alignment between diversity signals may be incorrect, which means that any signal combining or other diversity processing operations performed on diversity signals will produce sub-optimal results

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