ERROR Detection in Space Switches
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
This article describes a method of detecting errors in a space switch arising from faults in one or more input or output lines. In the disclosed technique, knowledge of the permutation function performed by the switch is not required. A space switch is a device that maps an input binary n-tuple to an output binary n-tuple such that the output vector is a permutation of the digits of the input vector. It can be shown that there are exactly n! distinct such permutations so that the space switch is simply a device that implements one such function in a given time. For any binary vector V = (v1, v2, ....vn), let W(V) be the Hamming weight, i.e., the number of non-zero digits in V. A permutation matrix P is a non-singular n by n square matrix with binary elements where each row and column has a weight of exactly one.