Fast transmitter based on table lookup

1. A method of differential modulating, spreading, over-sampling and filtering of a stream of data bits forming symbols for transmission, the method comprising:

determining an in-phase component I i and a quadrature component Q i for each symbol S i using differential modulation with respect to an I i−1 and a Q i−1 of a previous symbol S i−1 wherein i is an integer.

indexing a row of an I matrix for the in-phase components using two of I i−1 /Q i−1 , I i /Q i , and S i and providing samples in the indexed row as a spread, over-sampled, filtered output of I i ; and

indexing a row of a Q matrix for the quadrature components using two of I i−1 /Q i−1 , I i /Q i , and S i and providing samples in the indexed row as a spread, over-sampled, filtered output of Q i .

2. The method according to claim 1 , wherein each matrix has n rows, wherein n is equal to a number of possible combinations of values of said two of I i−1 /Q i−1 , I i /Q i , and S i and m columns, wherein m is equal to a spread factor times an over-sample factor.

3. The method according to claim 1 , including, prior to performing the method, determining the spreading, over-sampling and filtering of the stream of data bits and storing the spread, over-sampled and filtered stream of data bits in the rows of each matrix.

4. The method according to claim 1 , wherein the determining of I i and Q i uses a look-up table indexed by the previous I i−1 Q i−1 and the present symbol S i .

5. The method according to claim 4 , wherein the determining of I i and Q i is performed in one of in series with, in parallel with and simultaneously with indexing the I and Q matrices.

6. The method according to claim 4 , wherein the look-up table is part of one of the I and Q matrices.

7. The method according to claim 1 , wherein the determining of I i and Q i is performed in one of in series with, in parallel with and simultaneously with indexing the I and Q matrices.

8. The method according to claim 1 , wherein the determining uses one of BPSK and QPSK differential modulation.

9. The method according to claim 1 , including RF modulating and transmitting the output of the I i and Q i .

10. The method according to claim 9 , wherein the method is performed in a 802.11 protocol standard transmission.

11. A signal transmitter including means for performing the method of claim 1 .

12. A method of transmitting a stream of data bits forming symbols comprising:

determining for each symbol S i an in-phase component I i and a quadrature component Q i, wherein i is an integer;

indexing a matrix using two of a present symbol S i , a present I i, Q i pair and a previous I i−1, Q i−1 pair and providing a spread, over-sampled, filtered output sample of the I i, and Q i ;

RF modulating the output sample of I i, and Q i ; and

transmitting the RF modulated I i, and Q i .

13. The method according to claim 12 , wherein the matrix includes an I matrix and a Q matrix which are indexed using two of the present symbol Si, the present I i, Q i pair and the previous I i−1, Q i−1 pair.

14. The method according to claim 12 wherein the determining I i, and Q i uses differential modulation of the present symbol S i with respect to a previous symbol S i−1 .

15. The method according to claim 13 , wherein each of the I and Q matrices has n rows, wherein n is equal to a number of possible combinations of values of two of the previous I i−1, Q i−1 pair, and the present I i, Q i pair, and the present symbol S i and m columns, wherein m is equal to a spread factor times an over-sample factor.

16. The method according to claim 12 , wherein the determining I i, and Q i is performed in one of in series with, in parallel with and simultaneously with indexing the matrix.

17. A matrix device for processing a stream of data bits forming symbols S i , each of which has been modulated into an in-phase component I i and a quadrature component Q i for transmission, the matrix device comprises an I matrix device and a Q matrix device, each I and Q matrix device comprising:

n rows, wherein n is equal to a possible combination of the values of two of a previous I i−1, Q i−1 pair, the present I i, Q i pair, and the present symbol S i , wherein i is an integer;

m columns, wherein m is equal to a spread factor times an over-sample factor; and

each row including sample values corresponding to a spread, over-sampled, filtered I i, Q i .

18. The matrix device according to claim 17 , wherein the modulated I i, Q i are differential modulation of the present symbol Si with respect to a previous symbol S i−1 .

19. The matrix device according to claim 18 , wherein values of the present I i, Q i are included in each row as an additional column and wherein the rows are indexed by the previous I i−1, Q i−1 pair and the present symbol S i .