Channel Parameters

• Definition:
  The channel parameters mean different things depending on the type of Channel Model used. For the BSC, the channel parameters are the actual and estimate bit error probabilities. For the AWGN channel, the parameters are the actual and estimate noise variances.

  The actual parameter is the value that will be used to distort the data stream. For example, if the channel model is BSC and the actual parameter is 0.2, then the simulation will be generated with approximately 20% of the received bits being in error.

  The estimate parameter does not have anything to do with distorting the data. It is the value used by the Viterbi algorithm to determine branch and Path Measures. It is called the estimate value because, in the real world, you may not know exactly what the channel's bit error probability or noise variance is. So you would make an educated guess. Obviously, the algorithm will work best when the estimate value is the same as the actual value. The Workshop allows you to choose these values independently so you can experiment to see how a bad estimate of the channel parameter will affect the algorithm.

• Valid Input:
  For the BSC model, the parameters are probability values so they must be greater than or equal to 0 and less than or equal to 1.

  For the AWGN model, the parameters are noise variance values so they must be greater than or equal to 0.