Prediction device and method applied in a Viterbi decoder
First Claim
1. A prediction device applicable to a Viterbi decoder, said Viterbi decoder at least comprising a path computing module, a path metric comparison module, a plurality of path memories, a traceback module and a storage control module, said prediction device comprising:
- a prediction module receiving a path source of all states in a current stage from said path computing module and the state of the minimum path metric of the current stage from said path metric comparison module to determine whether the state of the minimum path metric of a previous stage is connected to the state of the minimum path metric of the current stage based on a prediction activation signal from said storage control module and the state of the minimum path metric of the previous stage stored in said prediction module, and outputting a prediction success signal to said storage control module; and
a plurality of decoded bit storages, each of said decoded bit storages corresponding to one of said path memories, and storing at least a decoded bit outputted by said prediction module or by said traceback module sequentially.
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Abstract
A prediction device and method for use in a Viterbi decoder is provided. The prediction device is applicable to a communication system with low bit error rate for reducing the count of accessing path memories, thereby lowering the power consumption of the system. The prediction device needs not activate the traceback modules when making a successful prediction. In other words, no access to the path memories is required. The predicted bits decoded and outputted by the decoded bit registers are the decoded bits from the Viterbi decoder. Therefore, the prediction device saves much traceback and power consumption for decoding.
14 Citations
13 Claims
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1. A prediction device applicable to a Viterbi decoder, said Viterbi decoder at least comprising a path computing module, a path metric comparison module, a plurality of path memories, a traceback module and a storage control module, said prediction device comprising:
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a prediction module receiving a path source of all states in a current stage from said path computing module and the state of the minimum path metric of the current stage from said path metric comparison module to determine whether the state of the minimum path metric of a previous stage is connected to the state of the minimum path metric of the current stage based on a prediction activation signal from said storage control module and the state of the minimum path metric of the previous stage stored in said prediction module, and outputting a prediction success signal to said storage control module; and a plurality of decoded bit storages, each of said decoded bit storages corresponding to one of said path memories, and storing at least a decoded bit outputted by said prediction module or by said traceback module sequentially. - View Dependent Claims (2, 3, 4)
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5. A prediction method applicable to a Viterbi decoder, said Viterbi decoder at least comprising a path computing module, a path metric comparison module, a plurality of path memories each corresponding to one decoded bit storage, a traceback module and a storage control module, said storage control module at least comprising a plurality of counters with each counter corresponding to one decoded bit storage, said prediction method comprising the following steps of:
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(a) using a prediction module to determine whether the state of the minimum path metric of a current stage is connected to the state of the minimum path metric of a previous stage based on a prediction activation signal from said storage control module and the state of the minimum path metric of the previous stage stored in said prediction module, said prediction module receiving a path source of all states in the current stage from said path computing module and the state of the minimum path metric of the current stage from said path metric comparison module; (b) waiting until a preset condition is met to return to step (a) for activating prediction if the state of the minimum path metric of the current stage is not connected to the state of the minimum path metric of the previous state; and (c) generating at least a decoded bit of the current stage, storing sequentially the decoded bit to one of said decoded bit storages, and adjusting the counter corresponding to the decoded bit storage currently used. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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Specification