Switching control method and apparatus for wireless telecommunications

• US 6,434,130 B1
• Filed: 08/19/1998
• Issued: 08/13/2002
• Est. Priority Date: 08/22/1997
• Status: Expired due to Term

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Soininen, Pekka, Rinne, Mikko
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US09/136,379
• Time in Patent Office: 1,455 Days
• Field of Search: 370/331, 370/335, 455/522
• US Class Current: 370/331
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

A switching method for a wireless telecommunication system which comprises at least one first station and at least one second station, includes the following steps. At a first station the power level of a signal received from a second station is determined, said first and second stations being in communication. A first value for the power level of the signal to be transmitted from the first station to the second station is provided based on the determined power level of the signal received from the second station. At the second station the power level of the signal received from said first station is determined. A second value for the power level of the signal to be transmitted from the first station to the second station is provided based on said determined power level of the signal received from the first station. The first and second values are compared and based on said comparison it is determined, if said second station is to be switched.

Claims

1. A switching method for a wireless telecommunication system comprising at least one first station and at least one second station, said method comprising the steps of:

determining at a first station the power level of a signal received from a second station, said first and second stations being in communication;

providing a first value for the power level of the signal to be transmitted from the first station to the second station based on said determined power level of the signal received from said second station;

determining at the second station the power level of the signal received from said first station;

providing a second value for the power level of the signal to be transmitted from the first station to the second station based on said determined power level of the signal received from the first station;

comparing said first and second values and based on said comparison determining if said second station is to be switched.

2. A method as claimed in claim 1, wherein in the comparing step the difference between said first and second values is determined.

3. A method as claimed in claim 1, wherein in the comparing step, the difference between the logarithms of the first and second values is determined.

4. A method as claimed in claim 2, wherein said second station is switched if said difference falls outside a predetermined range.

5. A method as claimed in claim 1, wherein said telecommunication system is a cellular telecommunication system.

6. A method as claimed in claim 5, wherein said second station is a base transceiver station or a mobile station.

7. A method as claimed in claim 5, wherein said first station is a mobile station or a base transceiver station.

8. A method as claimed in claim 5, wherein said cellular telecommunication network uses a code division multiple access technique.

9. A method as claimed in claim 8, wherein said code division multiple access technique is a wide band code division multiple access technique.

10. A method as claimed in claim 1, wherein in a packet data transmission mode, packet data can be transmitted between said first and second stations on a dedicated channel.

11. A method as claimed in claims 1, wherein in a packet data transmission mode, packet data can be transmitted between said first and second stations on a common channel.

12. A method as claimed in claim 11, further comprising the steps of selecting either the common channel or the dedicated channel to transmit said packet data in dependence on the length and/or frequency of the data packets.

13. A method as claimed in claim 1, wherein when said second station switching is activated, said first station ceases to communicate with said second station and starts communication with a different second station.

14. A method as claimed in claim 13, wherein said first station terminates its communication with said second station before it commences communication with the said different second station.

15. A method as claimed in an claim 1, wherein when said second station switching is activated, the connection between the said first station and the second station is broken and new connection is subsequently made between said first and second stations.

16. A method as claimed in claim 1, comprising the steps of:

measuring at the first station the strength of reference signals received from a plurality of said second station including the second station with which the first station is currently in communication; and

terminating the connection between the first station and the second station with which the first station is currently in communication if the stronger signal is received from another of said second stations.

17. A method as claimed in claim 13, wherein if the comparison of the first and second values is indicative of a failure in the path from the second station to said first station and the current second station is providing the strongest signal, then the connection between the first and second station will be broken and then subsequently re-established.

18. A method as claimed in claims 1, wherein if the comparing step determines that the first and second values are such that the second station should be switched, switching of the second station is delayed until the first and second values have maintained values indicative that switching should take place for a predetermined length of time.

19. A method as claimed in claim 18, wherein said second station is able to determine if the first station is moving and the predetermined time is set in dependence on the length of time required by the second station to determine if the first station is moving.

20. A method as claimed in claim 1, wherein if the comparing step determines that the first and second values are such that the second station should be switched, said first station and said second station provide only signals required to determine said first and second values and if the first and second values continue to be such that the second station should be switched, said second station is switched.

21. A method as claimed in claim 18, wherein if the comparing step determines that the first and second values no longer indicate that the second station should be switched, the connection between the first and second stations is continued.

22. A switching method for use in a cellular telecommunication system comprising at least one first station and at least one second station, the method comprising the steps of:

estimating for the first station a closed loop power level for transmission of a signal from the first station to a second station;

estimating for the first station an open loop power level for a signal to be transmitted from the first station to the second station;

comparing said estimated open loop and closed loop power levels, wherein if the difference between said estimated values falls outside a given range, second station is switched.

23. A first station for use in a wireless telecommunication system, said first station being arranged to communicate with a second station, said first station comprising:

means for estimating the power level of a signal received from said second station;

means for receiving a value for the power level of a signal to be transmitted from the first station to the second station from said second station; and

means for comparing the value estimated at said first station with the value transmitted from the second station and based on said comparison, said first station is arranged, if appropriate to send a signal to said second station indicative that second station switching is to take place.