Method, apparatus and system for random access

1. A method performed by a transceiver, comprising:

incorporating a signature sequence into a signal, wherein the signature sequence is one of a first set of signature sequences, wherein the first set of signature sequences is obtained from a Zadoff-Chu sequence with zero correlation zone, and the Zadoff-Chu sequence satisfies:

a ( k )= W N k(k+1)/2 , k= 0, 1 . . . , N− 1,

where W N =exp(−j2πr/N), N is an odd integer, r is relatively prime to N; and

transmitting the signal with the signature sequence;

wherein r corresponds to a reference received for the signature sequence.

2. The method of claim 1 , wherein a zero correlation zone of the signature sequence is associated with a size of a cell in which the signal with the signature sequence is transmitted.

3. The method of claim 1 , wherein the signature sequence is incorporated into a preamble portion of the signal.

4. The method of claim 3 , wherein the preamble portion of the signal comprises a cyclic prefix.

5. The method of claim 1 , wherein the set of signature sequences is specific to a cell in which the signal with the signature sequence is transmitted.

6. The method according to claim 1 , wherein the signal with the signature sequence is used for correlation with at least one signature sequence from a second set of signature sequences, wherein the first set of signature sequences is of a same set of signature sequences as the second set of signature sequences.

7. An apparatus operable in a cell of a wireless communications system, the apparatus comprising:

a processor configured to incorporate a signature sequence into a signal, wherein the signature sequence is one of a first set of signature sequences, wherein the first set of signature sequences is obtained from a Zadoff-Chu sequence with zero correlation zone, and the Zadoff-Chu sequence satisfying:

a ( k )= W N k(k+1)/2 , k= 0, 1, . . . , N− 1,

where W N =exp(−j2πr/N), N is an odd integer, r is relatively prime to N;

a circuitry, configured to transmit the signal with the signature sequence to a transceiver;

wherein r corresponds to a reference received for the signature sequence.

8. The apparatus of claim 7 , wherein a zero correlation zone of the signature sequence is associated with a size of the cell.

9. The apparatus of claim 7 , wherein the signature sequence is incorporated into a preamble portion of the signal.

10. The apparatus of claim 9 , wherein the preamble portion of the signal comprises a cyclic prefix.

11. The apparatus of claim 7 , wherein the value of r is indicated by the transceiver to the apparatus.

12. The apparatus of claim 7 , wherein the set of signature sequences is specific to the cell.

13. The apparatus according to claim 7 , wherein the signal with the signature sequence is used for correlation with at least one signature sequence from a second set of signature sequences, wherein the first set of signature sequences is of a same set of signature sequence as the second set of signature sequences.

14. The apparatus according to claim 7 , wherein a zero-correlation zone of said signature sequence of the first set of signature sequences is of a length-substantially corresponding to a maximum expected delay of a transmission from the apparatus to the transceiver.

15. An apparatus, comprising:

a transceiver, configured to

receive a synchronization signal being sent from a second transceiver over a random access channel, wherein the synchronization signal is designated for an uplink synchronization between the second transceiver and the apparatus within a cell in a multi-user cellular communication system, wherein a first signature sequence of a first set of signature sequences is used in a preamble portion of the synchronization signal, wherein the first set of signature sequences is obtained from a Zadoff-Chu sequence with zero correlation zone, and the Zadoff-Chu sequence satisfies:

a ( k )= W N k(k+1)/2 , k= 0, 1, . . . , N− 1,

where W N =exp(−j2πr/N), N is an odd integer, r is relatively prime to N; and

a processor, configured to

perform a correlation of the synchronization signal with a second set of signature sequences, the correlation being designated for detection of the first signature sequence;

wherein r corresponds to a reference received for the signature sequence.

16. The apparatus according to claim 15 , wherein the first set of signature sequences and the second set of signature sequences are of a same set of signature sequences.

17. The apparatus according to claim 15 , a zero-correlation zone of said signature sequence of the first set of signature sequences is of a length substantially corresponding to the maximum expected delay of a transmission from the second transceiver to the apparatus.

18. The apparatus according to claim 15 , wherein the correlation comprises:

correlating the synchronization signal with each signature sequence in the second set of signature sequences for a predetermined number of delays of the received signal by calculating aperiodic cross-correlation using a set of matched filters in the transceiver;

detecting a peak output from each matched filter; and

estimating a time of arrival of the first signature sequence to synchronize transmission between the second transceiver and the apparatus using the detected peak output from each filter.

19. A non-transitory computer readable medium, comprising:

a computer program code including executable instructions, which, when executed by an apparatus, to perform:

incorporating a signature sequence into a signal, wherein the signature sequence is one of a first set of signature sequences, wherein the first set of signature sequences is obtained from a Zadoff-Chu sequence with zero correlation zone, and the Zadoff-Chu sequence satisfies:

a ( k )= W N k(k+1)/2 , k= 0, 1, . . . , N− 1,

where W N =exp(−j2πr/N), N is an odd integer, r is relatively prime to N, wherein the signal with the signature sequence is then transmitted; wherein r corresponds to a reference received for the signature sequence.