Patent ID: 6950461

Claim:
A digital modem, comprising: a) a digital interface; and b) a transmitter coupled to said digital interface, said transmitter including a low density parity check (LDPC) encoder which generates redundant bits utilizing a substantially deterministically generated H matrix; c) a receiver coupled to said digital interface, said receiver including a LDPC decoder; and d) means for substantially deterministically generating said H matrix, said H matrix having a plurality of columns (M k ) and a plurality of rows (M j ), said means for generating said H matrix being associated with at least one of said transmitter and said receiver and including means for assigning a plurality of “ones” in a diagonal fashion within said H matrix so as to generate a plurality of diagonals of “ones” while not creating any rectangles of ones in said H matrix, wherein column distances between any two pairs of said plurality of diagonals are unique.