| 摘要 |
The attenuation and phase change of a communication channel have to be estimated for near-maximum-likelihood detection and this presents severe difficulties where rapid fading occurs especially in communication between mobile stations in cellular radio. A number of vectors are stored which represent possible sequences of received data symbols and these vectors are expanded on receipt of each further digital sample. Costs, representing a measure of the likelihood that sequences are correct, the lower the cost the higher the likelihood, are then derived for each vector on the basis of stored prediction of channel performance. Next the earliest data symbols in the vector with lowest costs are output as detected symbols and then the vectors with lowest costs as selected for storage in place of the original vectors. New channel predictions are formed from channel estimates for the current sample and stored for use in the next iteration.
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