Searching in dual-mode communications system

• US 20010028674A1
• Filed: 02/12/2001
• Published: 10/11/2001
• Est. Priority Date: 02/13/2000
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Shoev, Roni, Edlis, Ofir
• Granted Patent: US 7,085,308 B2
• Time in Patent Office: Days
• US Class Current: 375/130
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A method including searching for a pilot signal of a second communications system while substantially simultaneously being in communication with a first communications system.

Claims

1. A method comprising;

searching for a pilot signal of a second communications system while substantially simultaneously being in communication with a first communications system.

2. The method according to

claim 1

wherein said searching comprises:

recording on-line a portion of signals received from said second commmunications system; and

background processing said portion of signals to search for said pilot signal.

3. The method according to

claim 2

wherein said recording comprises recording a portion of spread spectrum signals and said processing comprises processing a portion of spread spectrum signals.

4. The method according to

claim 3

wherein said processing comprises performing Code Division Multiple Access (CDMA) acquisition.

5. The method according to

claim 2

wherein said recording and said processing comprise recording and processing a portion of CDMA signals while substantially simultaneously receiving RF signals at a different frequency on-line.

6. The method according to

claim 5

wherein said recording comprises recording said portion of CDMA signals after converting the portion of CDMA signals from an analog signal to a digital signal.

7. The method according to

claim 5

wherein said recording comprises recording said portion of CDMA signals after digitally processing the portion of CDMA signals.

8. The method according to

claim 4

wherein said performing of CDMA acquisition comprises finding a correlation between a pseudo-noise (PN) sequence of the recorded portion of CDMA signals and one of a plurality of known PN sequences.

9. The nethod according to

claim 8

and further comprising shifting the PN of the CDMA signals.

10. The method according to

claim 1

wherein said first communications system operates in a compressed mode of communication, said compressed mode comprising a gap period wherein there is generally no reception and transnission, and said searching comprises:

recording on-line a portion of signals received from said second communications system during said gap period; and

background processing said portion of signals to search for said pilot signal.

11. The method accordi to

claim 1

wherein communication signals from said first communications system comprise repetitions of sub-frames in a data frame, and said searching comprises:

recording on-line a portion of signals received from said second communications system during at least one said repetition of at least one said sub-frame in at least one said data frame; and

background processing said portion of signals to search for said pilot signal.

12. A dual mode receiver comprising:

a searcher adapted to search a pilot signal of a second communications system, while substantially simultaneously being in communication with a first communications system.

13. The receiver according to

claim 12

wherein said searcher comprises:

a memory adapted for recording on-line said portion of signals received from said second communications system; and

a background processing unit adapted to process sod portion of signals offline to search for said pilot signal.

14. The receiver according to

claim 13

wherein said portion of signals comprises a portion of spread spectrum signals.

15. The receiver according to

claim 13

wherein said portion of signals comprises a portion of CDMA signals.

16. The receiver according to

claim 15

wherein said CDMA signals comprise a PN sequence.

17. The receiver according to

claim 16

wherein said background processing unit is adapted to perform CDMA acquisition by processing said portion of CDMA signals offline.

18. The receiver according to

claim 17

wherein said background processing unit is adapted to find a correlation between the PN sequence of said portion of CDMA signals and one of a plurality of known PN sequences.

19. The receiver according to

claim 15

wherein said first and second communications system'"'"'s comprise at least one of CDMA, Advanced Mobile Phone Service (AMPS), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Global Mobile Systems (GSM) communications system'"'"'s.