Code design and implementation improvements for low density parity check codes for wireless routers using 802.11N protocol

1. A method for implementing Low Density Parity Check (LDPC) codes in an IEEE 802.11 standard system configured to operate in a Multiple-Input, Multiple-Output (MIMO) schema, comprising:

a) defining a base LDPC code, having a length equal to an integer number of data carriers in an ODFM symbol;

b) transmitting the base LDPC code over a plurality of sub-carriers, wherein the base code is transmitted at an expected phase on sub-carriers specified by the IEEE 802.11 standard system, and

c) transmitting the base LDPC code on sub-carriers other than those specified by the IEEE 802.11 standard system, wherein the base LDPC code on the other sub-carriers is transmitted offset in phase from the base LDPC code on the specified sub-carriers.

2. The method of claim 1 , wherein the base LDPC code is 192 bits long.

3. The method of claim 2 , further comprising using a longer LDPC code, wherein a length of the longer LDPC code is an integer multiple of the base LDPC code.

4. The method of claim 2 , wherein the specified sub-carriers are transmitted by a first transmission antenna and the other sub-carriers are transmitted by at least one other antenna.

5. The method of claim 2 , further comprising transmitting bits of the longer LDPC code sequentially on the specified sub-carriers and the other sub-carriers.

6. A Low Density Parity Check (LDPC) coded, IEEE 802.11 compatible Multiple-Input, Multiple-Output (MIMO) broadcast system, comprising:

an encoder, for receiving a base LDPC code having a length equal to an integer number of data carriers in an ODFM symbol, and for encoding information bits using the LDPC code;

a modulator, coupled to the encoder, for modulating the encoded information bits;

a transmitter, coupled to the modulator, for transmitting the modulated encoded information bits on a plurality of transmit antennas, wherein the modulated encoded information bits are transmitted on sub-carriers specified by an IEEE 802.11 standard system and on sub-carriers other than those specified by the IEEE 802.11 standard system, wherein transmissions on the sub-carriers other than those specified by the IEEE 802.11 standard system are offset in phase from transmissions on the sub-carriers specified by the IEEE 802.11 standard system.

7. The LDPC coded, IEEE 802.11 compatible MIMO broadcast system of claim 6 , further comprising:

a plurality of receive antennas for receiving the transmitted modulated encoded information bits;

a detector, coupled to the antennas, for detecting the presence of the transmitted modulated encoded information bits;

an LDPC decoder, coupled to the detector, for decoding the transmitted modulated encoded information bits; and

a demodulator, coupled to the LDPC decoder, for demodulating the transmitted modulated encoded information bits.

8. The LDPC coded, IEEE 802.11 compatible MIMO broadcast system of claim 7 , wherein the base LDPC code is 192 bits long.

9. The LDPC coded, IEEE 802.11 compatible MIMO broadcast system of claim 8 , further comprising using a longer LDPC code, wherein a length of the longer LDPC code is an integer multiple of the base LDPC code.

10. The LDPC coded, IEEE 802.11 compatible MIMO broadcast system of claim 9 , further comprising bits of the longer LDPC code being sequentially transmitted on the specified sub-carriers and other sub-carriers.

11. The LDPC coded, IEEE 802.11 compatible MIMO broadcast system of claim 8 , wherein the specified sub-carriers are transmitted by a first transmission antenna and other sub-carriers are transmitted by at least one other antenna.