Method for signal acquisition in a wireless terminal and wireless terminal

• US 7,295,535 B2
• Filed: 11/13/2002
• Issued: 11/13/2007
• Est. Priority Date: 11/13/2001
• Status: Active Grant

• Current Assignee: HMD Global Oy
• Original Assignee: Nokia Corporation
• Inventors: Halivaara, Ismo
• Primary Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US10/294,432
• Publication Number:
  US 20030091009A1
• Time in Patent Office: 1,826 Days
• Field of Search: 370/310, 370/328, 370/329, 370/335, 370/331, 370/342, 370/203, 370/208, 370/209, 370/431, 370/441, 370/320, 370/465, 370/468, 370/330, 455/67.11, 455/403, 455/422.1, 455/550.1, 455/561, 375/130, 375/150
• US Class Current: 370/329
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 7/2684 Synchronisation of a mobile station with more than one base station
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

The invention relates to a method for acquisition of a signal in a wireless terminal receiving a modulated signal transmitted by at least one base station. In the wireless terminal, timing information of the signal from at least two different base stations is used for the acquisition of the signal of at least one of said base stations. The invention also relates to a system, in which the method is applied, as well as to a wireless terminal.

Claims

1. A method, comprising:

receiving timing data of at least two base stations in a wireless terminal, and

performing acquisition of a modulated signal in said wireless terminal transmitted by at least one base station of said at least two base stations by using said timing data of said at least two base stations for performing said acquisition of the modulated signal in said terminal, wherein said timing data comprises a relative time difference between signals from said at least two base stations at a time of transmission.

2. The method according to claim 1, wherein in the acquisition of the modulated signal of the at least one base station, a correlation is made between the modulated signal of the at least one base station and a reference code corresponding to the code used in the modulation of the signal, wherein for the acquisition, a code phase of the reference code is adjusted, and wherein said timing data is used in the adjustment of the code phase.

3. The method according to claim 1, wherein said timing data from said at least two base stations comprises at least one of the following:

data about signal propagation time between the base station and the wireless terminal, data about positions of said at least two base stations.

4. The method according to claim 1, wherein acquisition of signals from at least three different base stations is performed, and wherein code phases determined during the acquisition of the signals from said at least three different base stations are used in positioning of the wireless terminal.

5. The method according to claim 2, wherein for distances of the base stations from the wireless terminal, a maximum distance is selected as a default value, and wherein said maximum distance is used in the adjustment of the code phase of said reference signal.

6. The method according to claim 1, wherein as said at least one base station, a base station serving the wireless terminal is used, wherein the wireless terminal receives the modulated signal of the serving base station, and wherein said timing data is related to neighboring base stations of said serving base station and is transmitted to the wireless terminal from said serving base station.

7. The method according to claim 6, wherein said timing data transmitted to the wireless terminal is about at least one neighbouring base station which does not neighbor said serving base station but which is a neighbor of at least one base station that does neighbor said serving base station.

8. The method according to claim 1, wherein the modulated signal transmitted by the at least one base station of the at least two base stations are spread spectrum modulated signals.

9. The method according to claim 1, wherein the base stations are base stations of the UMTS mobile communication system, and that acquisition of the signal of a pilot channel is performed.

10. The method according to claim 2, wherein for the acquisition, at least the following steps are taken in the wireless terminal:

acquisition of a modulated signal of a first base station, using said timing data of signals from at least two base stations to determine a transmission time difference between said first base station and a second base station, determining an estimate for a signal propagation time difference between said first base station and the wireless terminal and between said second base station and the wireless terminal, adjusting a code phase of a reference code based on said transmission time difference and said propagation time difference, and performing a correlation between a received signal and the reference code for acquisition of a modulated signal of the second base station.

11. A system comprising base stations and a wireless terminal with an antenna for receiving a modulated signal transmitted by at least one base station and a receiver for acquisition of the signal transmitted by the base station, wherein timing data of signals from at least two base stations is used for said acquisition of the modulated signal wherein said timing data comprises a relative time difference between signals from said at least two base stations at a time of transmission.

12. The system according to claim 11 comprising a control for making a correlation between the modulated signal transmitted by the base station and a reference code signal corresponding to a code used in modulation of the signal, and for adjusting a code phase of the reference code signal, and for using said timing data in the adjustment of the code phase.

13. The system according to claim 11, wherein said timing data of the signals from at least two different base stations comprises at least one of the following:

data about a signal propagation time between a base station and the wireless terminal, data about the positions of said at least two base stations.

14. The system according to claim 11, wherein code phases are determined during acquisition of signals from at least three different base stations for positioning of the wireless terminal.

15. The system according to claim 11, wherein the antenna of the wireless terminal is for receiving a signal of a serving base station, and that the system comprises a transmitter for transmitting data related to neighboring base stations of said serving base station to the wireless terminal.

16. The system according to claim 11, wherein the base stations are base stations of a UMTS mobile communication system, and said acquisition is of a signal of a pilot channel.

17. A wireless terminal comprising

an antenna for receiving timing data of at least two base stations transmitted by a base station and

a receiver for acquisition of a modulated signal transmitted by at least one base station and for using the timing data of the at least two base stations for acquisition of a signal of at least one of said base stations wherein said timing data of at least two base stations comprises a relative time difference between signals transmitted from said at least two base stations at a time of transmission.

18. The wireless terminal according to claim 17 said receiver comprising a control for making a correlation between the signal of the base station and a reference signal corresponding to a code used in modulation of the modulated signal, and for adjusting a code phase of the reference signal, and for using said timing data in the adjustment of the code phase.

19. The wireless terminal according to claim 17, wherein said timing data of at least two base stations comprises at least one of the following:

data about the signal propagation time between the base station and the wireless terminal, data about positions of said at least two base stations.

20. The wireless terminal according to claim 17, said receiver for acquiring a signal transmitted from at least three different base stations, and for using code phases determined during the acquisition of the signal from said at least three different base stations in positioning of the wireless terminal.

21. The wireless terminal according to claim 17, comprising a UMTS mobile communication device.