Systems and method for generating a common preamble for use in a wireless communication system
A UWB system comprising a plurality of piconets, wherein each piconet uses a different code to generate a preamble for use in communicating with a plurality of remote communication devices. The preamble can be generated from the combination of repeated versions of the code, negative versions of the code, and no code or zero, the codes used have a perfect autocorrelation function and optimal cross-correlation.
1. A method for wireless data communication, comprising:
generating a preamble code for a preamble of a frame to be transmitted to a wireless communication device, wherein the preamble code exhibits perfect periodic auto-correlation and optimum periodic cross-correlation in a wireless communication system, the cross-correlation results in a peak that is no larger than a square root of a peak of the auto-correlation, and the preamble code is generated by a circuit that:
selects preferred pairs of maximum length sequences of a length 2 N −1, wherein N is an odd number;
modifies the periodic cross-correlation values for the selected preferred pairs of maximum length sequences by adding 1 to the periodic cross-correlation values; and
divides the modified periodic cross-correlation values by 2 (N+1)/2 .
2. The method of claim 1 , wherein the periodic cross-correlation for the selected pairs of maximum length sequences is a 3 level signal.
3. The method of claim 1 , wherein N=5.
4. The method of claim 1 , wherein N=7.
5. The method of claim 1 , further comprising using the selected pairs of maximum length sequences to generate perfect ternary sequences with perfect periodic auto-correlation and optimum periodic cross-correlation.
6. An apparatus for wireless communication, comprising:
a circuit configured to generate a frame for transmission to a wireless communication device, the frame comprising a preamble, a header and a payload, wherein the preamble comprises a sync portion and a stop frame delimiter, the sync portion and the stop frame delimiter formed from a code, the code exhibits perfect periodic auto-correlation and optimum periodic cross-correlation, the cross-correlation results in a peak that is no larger than a square root of a peak of the auto-correlation, and the code is formed by:
selecting preferred pairs of maximum length sequences of a length 2 N −1, wherein N is an odd number,
modifying the periodic cross-correlation values for the selected preferred pairs of maximum length sequences by adding 1 to the periodic cross-correlation values, and
dividing the modified periodic cross-correlation values by 2 (N+1)/2 .
7. The apparatus of claim 6 , wherein the periodic cross-correlation for the selected pairs of maximum length sequences is a 3 level signal.
8. The apparatus of claim 6 , wherein N=5.
9. The apparatus of claim 6 , wherein N=7.
10. The apparatus of claim 6 , wherein the selected pairs of maximum length sequences are used to generate perfect ternary sequences with perfect periodic auto-correlation and optimum periodic cross-correlation.
11. The apparatus of claim 6 , wherein the sync portion is created by repeating the code a certain number of times.
12. The apparatus of claim 11 , wherein the sync portion is created by repeating positive or negative versions of the code a certain number of times.
13. The apparatus of claim 6 , wherein the stop frame delimiter is constructed by using zeroes, the code, or negative versions of the code.
14. The apparatus of claim 6 , wherein the preamble comprises a equal number of negative and positive versions of the code.
15. The apparatus of claim 6 , wherein the code comprises half zeroes.
16. The method of claim 1 , further comprising creating a sync portion of the preamble by repeating the code a certain number of times.
17. The method of claim 16 , wherein the sync portion is created by repeating positive or negative versions of the code a certain number of times.
18. The method of claim 1 , further comprising constructing a stop frame delimiter of the preamble by using zeroes, the code, or negative versions of the code.
19. The method of claim 1 , wherein the preamble comprises an equal number of negative and positive versions of the code.
20. The method of claim 1 , further comprising transmitting the frame to the wireless communication device.
21. The apparatus of claim 1 , further comprising a transmitter configured to transmit the frame to the wireless communication device.
22. A wireless communication device, comprising:
a circuit configured to generate a frame for transmission, the frame comprising a preamble, a header and a payload, wherein the preamble is formed from a code that exhibits perfect periodic auto-correlation and optimum periodic cross-correlation, the cross-correlation results in a peak that is no larger than a square root of a peak of the auto-correlation, and the code is formed by:
selecting preferred pairs of maximum length, sequences of a length 2 N −1, wherein N is an odd number,
modifying the periodic cross-correlation values for the selected preferred pairs of maximum length sequences by adding 1 to the periodic cross-correlation values, and
dividing the modified periodic cross-correlation values by 2 (N+1)/2 ;
an antenna; and
a transmitter configured to transmit the frame via the antenna.
23. The wireless communication device of claim 22 , wherein the transmitter comprises an impulse transmitter configured to transmit the frame in short, pulses.