Claims
- 1. A method for facilitating cell searches in a cellular communications system, comprising the steps of:
a base station generating an identifying code set for transmission, said identifying code set comprising a plurality of code words including a plurality of symbols from a set of short codes, each code word of said plurality of code words defined such that no symbol-wise cyclic shift of said each code word produces a valid code word; and said base station transmitting said generated identifying code.
- 2. The method of claim 1, wherein said plurality of code words comprises a plurality of Q-ary code words, and said set of short codes comprises a set of Q short codes.
- 3. The method of claim 2, wherein said plurality of Q-ary code words comprises a plurality of length M Q-ary code words.
- 4. The method of claim 1, wherein said identifying code is formed by concatenating an inner and outer code.
- 5. The method of claim 4, wherein said inner code comprises a tailbiting trellis code.
- 6. The method of claim 4, wherein said outer code comprises a binary code.
- 7. The method of claim 5, wherein said tailbiting trellis code comprises an orthogonal trellis code.
- 8. The method of claim 5, wherein said tailbiting trellis code comprises a superorthogonal trellis code.
- 9. A method for a mobile station to decode an identifying code transmitted from a base station in a CDMA cellular communications system, comprising the steps of:
receiving a plurality of consecutive symbols comprising said identifying code; determining whether said received plurality of consecutive symbols comprises a valid code word; and if said received plurality of consecutive symbols does not comprise a valid code word, cyclically shifting said received plurality of consecutive symbols by a predetermined amount, and returning to the determining step; if said received plurality of consecutive symbols comprises a valid code word, outputting a number of cyclical shifts made to obtain said valid code word and a message associated with said valid code word.
- 10. The method of claim 9, wherein said number of cyclical shifts made to obtain said valid code word indicates a frame timing for said valid code word.
- 11. The method of claim 9, wherein said plurality of consecutive symbols comprises a predetermined number of consecutive symbols.
- 12. The method of claim 9, wherein said predetermined amount comprises one symbol.
- 13. A method for a mobile station to decode an identifying code transmitted from a base station in a CDMA cellular communications system, comprising the steps of:
collecting k times M consecutive symbols, said M consecutive symbols comprising said identifying code; calculating a combined likelihood value for said collected k times M consecutive symbols; for each of L code words and each of M cyclic shifts of said collected consecutive symbols, computing a correlation between said k times M collected consecutive symbols and all of M times L consecutive symbols obtained; and storing a code word and number of cyclical shifts made that produced a highest amount of correlation in the computing step.
- 14. The method of claim 13, wherein said number of cyclical shifts made indicate a frame timing for said identifying code.
- 15. The method of claim 13, further comprising the step of outputting a message associated with said stored code word.
- 16. A method for encoding an identifying code to be transmitted from a base station in a CDMA cellular communications system, comprising the steps of:
computing a period for each of 2M words of length M to be encoded as said identifying code; excluding each of said 2M words that has a period less than M; for each of M cycles of a remainder of said 2M words, determining a representative word; and storing each said representative word.
- 17. The method of claim 16, wherein each said stored representative word includes a plurality of code words and no cyclic shift of any one of said plurality of code words produces a valid code word.
RELATED APPLICATION
[0001] This Application for Patent claims the benefit of priority from, and hereby incorporates by reference the entire disclosure of, co-pending U.S. Provisional Application for Pat. Ser. No. 60/057,412, filed Aug. 29, 1997.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60057412 |
Aug 1997 |
US |
Continuations (1)
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Number |
Date |
Country |
Parent |
09129151 |
Aug 1998 |
US |
Child |
09742714 |
Dec 2000 |
US |