Filtering and guard band for non-synchronized transmission

1. A method for communication, the method comprising

selecting a sequence from a group of sequences for random access;

allocating at least one sub-carrier on an uplink channel for at least one random access channel (RACH), the uplink channel comprising at least one data channel, and each data channel comprising a continuous set of data sub-carriers;

creating a guard band on each side of the at least one RACH by applying a raised cosine filter before transmitting the selected sequence using the RACH, wherein creating the guard band on each side of the at least one RACH further comprises:

for each continuous set of multiple RACHs among the at least one RACH, applying the raised cosine filter to a first frequency bandwidth that corresponds to a combination of a first set of sub-carriers adjacent to a first side of the continuous set of multiple RACHs, the continuous set of multiple RACHs, and a second set of sub-carriers adjacent to a second side of the continuous set of multiple RACHs;

mapping the selected sequence to the at least one RACH to generate a at least one RACH signal; and

transmitting the at least one RACH signal to a base station.

2. The method of claim 1 , the raised cosine filter having a roll-off coefficient of approximately 0.12.

3. The method of claim 1 , wherein creating the guard band on each side of the at least one RACH further comprises:

for each non-continuous RACH among the at least one RACH, applying the raised cosine filter to a second frequency bandwidth that corresponds to the non-continuous RACH.

4. The method of claim 3 , the raised cosine filter having a roll-off coefficient of approximately 0.12.

5. The method of claim 1 , wherein at least one of the first set of sub-carriers and the second set of sub-carriers comprises at least a portion of a data channel adjacent to the continuous set of multiple RACHS.

6. The method of claim 1 , the group of certain sequences comprising a Zadoff-Chu sequence and a Generalized Chirp-Like sequence.

7. A wireless terminal comprising:

a transmitter configured to transmit signals to a base station over an uplink channel; and

a processor configured to:

select a sequence from a group of certain sequences,

allocate at least one subcarrier on the uplink channel for at least one random access channel (RACH), the uplink channel comprising at least one data channel, and each data channel comprising a continuous set of data sub-carriers,

create a guard band on each side of the at least one RACH by applying a raised cosine filter before transmitting the selected sequence using the RACH, wherein to create the guard band on each side of the at least one RACH the processor is further configured to, for each continuous set of multiple RACHs among the at least one RACH, apply the raised cosine filter to a second frequency bandwidth that corresponds to a combination of a first set of data sub-carriers adjacent to a first side of the continuous set of multiple RACHs, the continuous set of multiple RACHs, and a second set of data sub-carriers adjacent to a second side of the continuous set of multiple RACHs,

map the selected sequence to the at least one RACH to generate a RACH signal, and

control the transmitter to transmit the RACH the base station.

8. The wireless terminal of claim 7 , the raised cosine filter having a roll-off coefficient of approximately 0.12.

9. The wireless terminal of claim 7 , wherein to create the guard band on each side of the at least on RACH, the processor is further configured to:

for each non-continuous RACH among the at least one RACH, apply the raised cosine filter to a first frequency bandwidth that corresponds to the non-continuous RACH.

10. The wireless terminal of claim 9 , the raised cosine filter having a roll-off coefficient of approximately 0.12.

11. The wireless terminal of claim 7 , wherein at least one of the first set of sub-carriers and the second set of sub-carriers comprises at least a portion of a data channel adjacent to the continuous set of multiple RACHS.

12. The wireless terminal of claim 7 , the group of certain sequences comprising a Zadoff-Chu sequence and a Generalized Chirp-Like sequence.

13. A wireless communication system comprising:

a first wireless communication device configured to:

select a sequence from a group of certain sequences;

allocate at least one sub-carrier on an uplink channel for at least one random access channel (RACH), the uplink channel comprising at least one data channel, and each data channel comprising a continuous set of data sub-carriers,

create a guard band on each side of the at least one RACH by applying a raised cosine filter before transmitting the selected sequence on the RACH, wherein to create the guard band on each side of the at least on RACH, the first wireless communication device is further configured to, for each continuous set of multiple RACHs among the at least one RACH, apply the raised cosine filter to a second frequency bandwidth that corresponds to a combination of a first set of data sub-carriers adjacent to a first side of the continuous set of multiple RACHs, the continuous set of multiple RACHs, and a second set of data sub-carriers adjacent to a second side of the continuous set of multiple RACHs,

map the selected sequence to the at least one RACH to generate a RACH signal, and

transmit the RACH signal; and

a second wireless communication device configured to receive the RACH signal comprising the selected sequence, and transmit timing synchronization information to the first wireless communication device.

14. The wireless communication system of claim 13 , the Raised Cosine filter having a roll-off coefficient of approximately 0.12.

15. The wireless communication system of claim 13 , wherein to create the guard band on each side of the at least on RACH, the first wireless communication device is further configured to:

for each non-continuous RACH among the at least one RACH, apply the raised cosine filter to a first frequency bandwidth that corresponds to the non-continuous RACH.

16. The wireless communication system of claim 15 , the Raised Cosine filter having a roll-off coefficient of approximately 0.12.

17. The wireless communication system of claim 15 , wherein at least one of the first set of sub-carriers and the second set of sub-carriers comprises at least a portion of a data channel adjacent to the continuous set of multiple RACHS.

18. The wireless communication system of claim 13 , the group of certain sequences comprising a group of a Zadoff-Chu sequence and a Generalized Chirp-Like sequence.

19. The wireless communication system of claim 13 , wherein the timing synchronization information comprises timing advance information.

20. The wireless communication system of claim 13 , wherein the first wireless communication device is further configured to receive the timing synchronization information, adjusts an uplink timing using the timing synchronization information, and send an uplink scheduling request to the second wireless communication device.