This function checks if the given input is of trellis structure
[ISOK, STATUS] = ISTRELLIS(S) returns [T,''] if the given input is valid trellis structure. Otherwise ISOK is F and STATUS indicates the reason for invalidity
Fields in trellis structure are numInputSymbols, (number of input symbols) numOutputSymbols, (number of output symbols) numStates, (number of states) nextStates, (next state matrix) outputs, (output matrix)
Properties of the fields are as follows numInputSymbols and numOutputSymbols should be a power of 2 (as data is represented in bits). The 'nextStates' and 'outputs' fields are matrices of size 'numStates' x 'numInputSymbols' . Each element in the 'nextStates' matrix and 'output' matrix is an integer value between zero and (numStates-1). The (r,c) element of the 'nextStates' matrix and 'output' matrix,denotes the next state and output respectively when the starting state is (r-1) and the input bits have decimal representation (c-1).
To convert to decimal value, use the first input bit as the most significant bit (MSB).
Valid trellis structure trellis.numInputSymbols = 4; trellis.numOutputSymbols = 4; trellis.numStates = 3; trellis.nextStates = [0 1 2 1;0 1 2 1; 0 1 2 1]; trellis.outputs = [0 0 1 1;1 1 2 1; 1 0 1 1]; [isok,status] = istrellis(trellis) Inavlid trellis structure trellis.numInputSymbols = 3; trellis.numOutputSymbols = 3; trellis.numStates = 3; trellis.nextStates = [0 1 2 ;0 1 2 ; 0 1 2 ]; trellis.outputs = [0 0 1 ;1 1 2 ; 1 0 1 ]; [isok,status] = istrellis(trellis) |  |  |