| 摘要 |
A method of estimating signal-to-noise ratio in a Viterbi decoder comprising: setting a threshold SNR value; determining a dependence on SNR of the average decoding path length; filling branch metrics matrix, minimal path metrics matrix, path metrics matrix and paths matrix with initial values; receiving packets from a communication channel; calculating the matrices that contains paths stored during operation of Viterbi algorithm in its rows, and a minimal path metrics matrix, including calculating an estimate of a decoding path length, where all the paths converge, based on the paths matrix; calculating current SNR estimate using an estimate of a decoding path length, based on results of previous steps; setting a decoder control signal to an active state if the current estimated SNR does not exceed the threshold, and to an inactive state otherwise; if the decoder control signal is in active state, the branch metrics matrix, the minimal path metrics matrix, the paths metrics matrix and the paths matrix are filled with the initial values; generating a decoded symbol; and repeating the steps on a next packet if one is available. |
