Method and apparatus for achieving system acquisition and other signaling purposes using the preamble in an OFDM based communications system
View Patent ↗In the system acquisition process system information is non-coherently detected using correlation of reconstructed and received preamble signals, such as the primary broadcast control channel (PBCCH) and the acquisition pilots (TDM 1 , TDM 2 , and TDM 3 ). The phase correlation signals between the correlated signals of PBCCH and TDM 2 or TDM 3 and between the correlated signals of TDM 2 and TDM 3 are combined to decode other sector interference (OSI) information and the like. Acquisition is also made more efficient by taking advantage of predictable information based on system synchronicity. The sync/async bit is included in at least one of the acquisition pilots. The mobile then uses knowledge of system synchronicity to more efficiently detect the additional information in the superframe preamble.
1. A method comprising:
indicating at least timing, channel bandwidth, and system synchronicity in a first acquisition pilot (TDM 1 );
sequencing said TDM 1 using one of a plurality of time-repeating sequences;
forming a second and third acquisition pilot (TDM 2 and TDM 3 ) using information selected according to said system synchronicity, wherein one of said TDM 1 , TDM 2 and TDM 3 comprises a cyclic prefix length and another one of said TDM 1 , TDM 2 and TDM 3 comprises sync/async information, wherein said TDM 2 comprises a first portion of a pilot phase or sector identity information, and wherein said TDM 3 comprises a remaining portion of the pilot phase or sector identity info information but does not comprise the first portion; and
transmitting a superframe preamble including said TDM 1 , TDM 2 , and TDM 3 .
2. The method of claim 1 further comprising:
receiving said superframe preamble by a mobile station;
detecting said system synchronicity in said TDM 1 ; and
decoding said selected information in said TDM 2 and TDM 3 according to said detected synchronicity.
3. The method of claim 2 further comprising:
comparing said decoded selected information from expected information corresponding to said detected system synchronicity;
declaring an error when said decoded selected information does not correlate to said expected information; and
re-processing said superframe preamble for said system synchronicity.
4. A computer program product having a non-transitory computer readable medium with computer program logic recorded thereon, said computer program product comprising:
code for indicating at least timing, channel bandwidth, and system synchronicity in a first acquisition pilot (TDM 1 );
code for sequencing said TDM 1 using one of a plurality of time-repeating sequences;
code for forming a second and third acquisition pilot (TDM 2 and TDM 3 ) using information selected according to said system synchronicity, wherein one of said TDM 1 , TDM 2 and TDM 3 comprises a cyclic prefix length and another one of said TDM 1 , TDM 2 and TDM 3 comprises sync/async information, wherein said TDM 2 comprises a first portion of a pilot phase or sector identity information, and wherein said TDM 3 comprises a remaining portion of the pilot phase or sector identity information but does not comprise the first portion; and
code for transmitting a superframe preamble including said TDM 1 , TDM 2 , and TDM 3 .
5. The computer program product of claim 4 further comprising:
code for receiving said superframe preamble by a mobile station;
code for detecting said system synchronicity in said TDM 1 ; and
code for decoding said selected information in said TDM 2 and TDM 3 according to said detected synchronicity.
6. The computer program product of claim 5 further comprising:
code for comparing said decoded selected information from expected information corresponding to said detected system synchronicity;
code for declaring an error when said decoded selected information does not correlate to said expected information; and
code for re-processing said superframe preamble for said system synchronicity.
7. A computer program product having a non-transitory computer readable medium with computer program logic recorded thereon, said computer program product comprising:
code for receiving a superframe preamble by a mobile station, wherein said superframe preamble includes first, second and third acquisition pilots (TDM 1 , TDM 2 , and TDM 3 ), wherein said TDM 1 indicates at least timing, channel bandwidth, and system synchronicity, and wherein said TDM 1 is sequenced with one of a plurality of time-repeating sequences;
code for detecting said system synchronicity in said TDM 1 ; and
code for decoding information in said TDM 2 and TDM 3 according to said detected synchronicity, wherein one of said TDM 1 , TDM 2 and TDM 3 comprises a cyclic prefix length and another one of said TDM 1 , TDM 2 and TDM 3 comprises sync/async information, wherein said TDM 2 comprises a first portion of a pilot phase or sector identity information, and wherein said TDM 3 comprises a remaining portion of the pilot phase or sector identity information but does not comprise the first portion.
8. The computer program product of claim 7 further comprising:
code for comparing said decoded information with expected information corresponding to said detected system synchronicity;
code for declaring an error when said decoded information does not correlate to said expected information; and
code for re-processing said superframe preamble for said system synchronicity.
9. A method comprising:
receiving a superframe preamble by a mobile station, wherein said superframe preamble includes first, second and third acquisition pilots (TDM 1 , TDM 2 , and TDM 3 ), wherein said TDM 1 indicates at least timing, channel bandwidth, and system synchronicity, and wherein said TDM 1 is sequenced with one of a plurality of time-repeating sequences;
detecting said system synchronicity in said TDM 1 ; and
decoding information in said TDM 2 and TDM 3 according to said detected synchronicity, wherein one of said TDM 1 , TDM 2 and TDM 3 comprises a cyclic prefix length and another one of said TDM 1 , TDM 2 and TDM 3 comprises sync/async information, wherein said TDM 2 comprises a first portion of a pilot phase or sector identity information, and wherein said TDM 3 comprises a remaining portion of the pilot phase or sector identity information but does not comprise the first portion.
10. The method of claim 9 further comprising:
comparing said decoded information with expected information corresponding to said detected system synchronicity;
declaring an error when said decoded information does not correlate to said expected information; and
re-processing said superframe preamble for said system synchronicity.
11. The method of claim 1 , wherein said TDM 1 comprises the cyclic prefix length and said TDM 3 comprises the sync/async information.
12. The method of claim 1 , wherein said TDM 3 comprises the cyclic prefix length and said TDM 1 comprises the sync/async information.
13. The computer program product of claim 4 , wherein said TDM 1 comprises the cyclic prefix length and said TDM 3 comprises the sync/async information.
14. The computer program product of claim 4 , wherein said TDM 3 comprises the cyclic prefix length and said TDM 1 comprises the sync/async information.
15. The computer program product of claim 7 , wherein said TDM 1 comprises the cyclic prefix length and said TDM 3 comprises the sync/async information.
16. The computer program product of claim 7 , wherein said TDM 3 comprises the cyclic prefix length and said TDM 1 comprises the sync/async information.
17. The method of claim 9 , wherein said TDM 1 comprises the cyclic prefix length and said TDM 3 comprises the sync/async information.
18. The method of claim 9 , wherein said TDM 3 comprises the cyclic prefix length and said TDM 1 comprises the sync/async information.