System and method for transmitting data

A transmitter for transmitting packets of data along a plurality of paths, said data being transmitted along each path in sub-packets containing at most p.sup.n -1 symbols, where p is a prime number, n is a positive integer and the number of different possible symbols is an integer power of p, comprising:

• a circuit for routing respective sub-packets along respective said paths;
• a first cyclic redundancy check generator in a first of said paths, using a first predetermined cyclic redundancy check polynomial of degree b greater than n;
• and
• a second cyclic redundancy check generator in a second of said paths, using a second predetermined cyclic redundancy check polynomial of degree b and which is different from said first cyclic redundancy check polynomial;
• said first and second cyclic redundancy check polynomials being chosen to have the property that, when all arithmetic is carried out modulo p, each said polynomial has a respective factor of degree at least b-n+1 such that the collection of polynomials which are each exactly divisible by all such factors constitutes a BCH code.

A receiver for receiving data sub-packets transmitted along a plurality of paths, each sub-packet containing at most p.sup.n -1 symbols, where p is a prime number, n is a positive integer and the number of different possible symbols is an integer power of p, comprising:

• a first cyclic redundancy check comparator in a first of said paths, using a first predetermined cyclic redundancy check polynomial of degree b greater than n;
• and
• a second cyclic redundancy check comparator in a second of said paths, using a second predetermined cyclic redundancy check polynomial of degree b and which is different from said first cyclic redundancy check polynomial;
• said first and second cyclic redundancy check polynomials being chosen to have the property that, when all arithmetic is carried out modulo p, each said polynomial has a respective factor of degree at least b-n+1 such that the collection of polynomials which are each exactly divisible by all such factors constitutes a BCH code.

A method of transmitting data along each of a plurality of paths in sub-packets containing at most p.sup.n -1 symbols, where p is a prime number, n is a positive integer and the number of different possible symbols is an integer power of p, comprising the steps of:

• assembling data into sub-packets for each path;
• applying a cyclic redundancy check code to data sub-packets for each path, using a respective and different cyclic redundancy check polynomial of degree b greater than n for each path;
• transferring the data sub-packets along the respective paths;
• receiving the transferred data sub-packets;
• and
• checking the data sub-packets transferred along each path for occurrence of errors, using the cyclic redundancy check code applied to each sub-packet and the respective cyclic redundancy check polynomial for each path;
• said different cyclic redundancy check polynomials being chosen to have the property that, when all arithmetic is carried out modulo p, each said polynomial has a respective factor of degree at least b-n+1 such that the collection of polynomials which are each exactly divisible by all such factors constitutes a BCH code.