Code design and implementation improvements for low density parity check codes for multiple-input multiple-output channels
Methods and systems for designing LDPC codes are disclosed. A method in accordance with the present invention comprises configuring a plurality (M) of parallel accumulation engines, accumulating a first information bit at a first set of specific parity bit addresses using the accumulation engines, increasing a parity bit address for each of the parity bit addresses by a pre-determined offset for each new information bit, accumulating subsequent information bits at parity bit addresses offset from the parity bit addresses by a pre-determined offset until an M+1 information bit is reached, accumulating the next M information bits at a second set of specific parity bit addresses using the parallel accumulation engines, increasing a parity bit address for each member of the second set of parity bit addresses by the pre-determined offset for each new information bit; and repeating accumulating and increasing the addresses until the information bits are exhausted.
1. A method for generating Low Density Parity Check (LDPC) codes from input data comprising a plurality of information bits into parity bits of the LDPC codes for use in broadcast systems, comprising:
a) accepting the plurality of information bits at a LDPC encoder;
b) accumulating a first information bit at a first set of specific parity bit addresses using the LDPC encoder;
c) increasing a parity bit address for each member of the first set of specific parity bit addresses by a pre-determined offset for each new information bit;
d) accumulating subsequent information bits at parity bit addresses that are offset from the specific parity bit addresses by a pre-determined offset until an M+1 information bit is reached;
e) accumulating the next M information bits at a second set of specific parity bit addresses using the LDPC encoder;
f) increasing a parity bit address for each member of the second set of specific panty bit addresses by the pre-determined offset for each new information bit; and
repeating (e) through (f) until the information bits are exhausted.
2. The method of claim 1 , wherein accepting the plurality of information bits at the LDPC encoder comprises accepting the plurality of information bits in a Multiple-Input, Multiple-Output (MIMO) system.
3. The method of claim 2 , wherein accumulating the subsequent information bits at parity bit addresses that are offset from the specific parity bit addresses by a different pre-determined offset, the different pre-determined offset being code-dependent.
4. The method of claim 3 , further comprising accumulating the parity bits by adding each parity bit address to the immediately preceding parity bit address.
5. The method of claim 4 , further comprising transmitting the LDPC codes by a plurality of antennas.
6. The method of claim 5 , further comprising limiting a number of bit nodes in the parity check matrix to 400.
7. The method of claim 5 , wherein the LDPC codes are short block length codes.