Method, apparatus and system for decoding a non-coherently demodulated signal
AssigneeMotorola, Inc.
InventorColin D. Frank
Life of this patent
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Abstract
Non-coherently demodulated signals are efficiently decoded using a non-complex system that is independent of the fading statistics of the channel. A symbol metric calculator (406) receives a signal-to-noise ratio (404) and symbols from a non-coherently demodulated signal (402) to efficiently produce weighted symbol metrics (408). A symbol metric deinterleaver (410) is then used to deinterleave the weighted symbol metrics. A decoder (414) produces a decoded bit sequence(416) based on the deinterleaved weighted symbol metrics (412).
Claims16
A method for efficiently decoding a non-coherently demodulated signal in a communication system, wherein the non-coherently demodulated signal includes a plurality of M-ary symbols each with M outputs and corresponding to k data symbols, where M equals 2.sup.k, and the non-coherently demodulated signal is used to calculated a signal-to-noise ratio, the method comprising the steps of:
- a) calculating k weighted symbol metrics, for each M-ary symbol, based on the signal-to-noise ratio and the M outputs to produce a plurality of weighted symbol metrics;
- b) deinterleaving, using a symbol metric deinterleaver, the plurality of weighted symbol metrics to produce a plurality of deinterleaved weighted symbol metrics;
- and
- c) selecting a code sequence which is maximum-likelihood using the plurality Of deinterleaved weighted Symbol metrics and providing a corresponding decoded bit sequence.
An apparatus in a communication system for efficiently decoding a non-coherently demodulated signal, wherein the non-coherently demodulated signal includes a plurality of M-ary symbols each with M outputs and corresponding to k data symbols, where M equals 2.sup.k, and the non-coherently demodulated signal is used to calculate a signal-to-noise ratio, comprising:
- a) a symbol metric calculator for receiving the signal-to-noise ratio and the M outputs representing symbols, and calculating k weighted symbol metrics for each M-ary symbol to produce a plurality of weighted symbol metrics;
- b) a symbol metric deinterleaver, coupled to the symbol metric calculator, for deinterleaving the plurality of weighted symbol metrics and producing a plurality of deinterleaved weighted symbol metrics;
- and
- c) a Viterbi decoder, coupled to the symbol metric deinterleaver, for selecting a maximum-likelihood code sequence using the plurality of deinterleaved weighted symbol metrics and providing a decoded bit sequence.
A system having an apparatus for efficiently decoding a received signal, wherein the received signal is binary encoded, bit interleaved, and modulated using M-ary modulation, where M equals 2.sup.k and k is a number of data symbols, the receiver system comprising:
- a) a M-ary demodulator device for producing a non-coherently demodulated signal in response to the received signal;
- b) a square-law combiner, coupled to the M-ary demodulator, for producing M outputs from the non-coherently demodulated signal;
- c) a signal-to-noise ratio calculator, coupled to the square-law combiner, for computing a signal-to-noise ratio in response to the M outputs;
- d) a delay element, coupled to the square-law combiner, for producing M delayed outputs based upon the M outputs representing symbols from the square-law combiner;
- e) a symbol metric calculator, coupled to the signal-to-noise calculator and the delay element, for receiving the signal-to-noise ratio and the M delayed outputs and producing a plurality of weighted symbol metrics;
- f) a symbol metric deinterleaver, coupled to the symbol metric calculator, for producing a plurality of deinterleaved weighted symbol metrics utilizing the plurality of weighted symbol metrics;
- and
- g) a Viterbi decoder, coupled to the symbol metric deinterleaver, for selecting a maximum-likelihood code sequence using the plurality of deinterleaved weighted symbol metrics and providing a decoded bit sequence.
Dependencies are inferred from the claim text.