Method of WCDMA coverage based handover triggering

• US 20020187784A1
• Filed: 06/06/2001
• Published: 12/12/2002
• Est. Priority Date: 06/06/2001
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Holma, Harri, Schwarz, Uwe, Heikkinen, Kai, Artamo, Atte, Tigerstedt, Karl, Wacker, Achim
• Granted Patent: US 6,615,044 B2
• Time in Patent Office: Days
• US Class Current: 455/439
• CPC Class Codes: H04W 36/0088 Scheduling hand-off measurements
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 36/302 due to low signal strength

Abstract

A method of triggering an IF or IS handover between two WCDMA carrier or a WCDMA carrier and a GSM carrier. Six triggering conditions are used to initiate the search for an alternative network connection by starting the handover measurements. These triggering conditions are: a) the mobile terminal TxPwr has exceeded its threshold value longer than a specified time; b) the connection based power in the downlink has exceeded its threshold value longer than a specified time; c) the mobile terminal TxPwr has reached the maximum value a specified number of times; d) the SIR target at the base station has risen above a specified threshold value over a period of time; e) the mobile terminal TxPwr has exceeded its threshold value and the gradient of the power control signature indicates sudden rise to maximum power level; and f) the pilot power measured at the mobile terminal has fallen below a threshold value for long than a specified time.

Claims

1. A method of triggering a handover event in telecommunication networks having a plurality of base stations operated by a plurality of network operators each having one or more frequency carriers, wherein the handover event is used in a frequency division multiplex (FDD) mode of a mobile terminal capable of communicating with one or more base stations of the telecommunication networks over corresponding uplink and downlink, for allowing the mobile terminal to move from the radio coverage area of a first frequency carrier to the radio coverage area of a second frequency carrier while maintaining communication with one or more base stations, wherein the handover event is performed based on signal strength and/or signal quality measurement, said method comprising the steps of:

obtaining a first signal indicative of a triggering parameter;

determining from the first signal whether the triggering parameter has fulfilled a triggering condition regarding a reference value; and

providing a second signal when the triggering parameter has fulfilled the triggering condition for starting the signal strength and/or signal quality measurement.

2. The method of claim 1, wherein the triggering parameter is indicative of a transmission power of the mobile terminal in the uplink, and the reference value is indicative of a threshold value for the transmission power, and wherein the triggering condition is fulfilled when the transmission power has exceeded the threshold value over a predetermined period of time.

3. The method of claim 1, wherein the triggering parameter is indicative of a transmission power in the downlink to the mobile terminal, and the reference value is indicative of a threshold value of the transmission power, and wherein the triggering condition is fulfilled when the transmission power has exceeded the threshold value over a predetermined period of time.

4. The method of claim 1, wherein the triggering parameter is indicative of a transmission power of the mobile terminal and the reference value is a maximum value of the transmission power, and wherein the triggering condition is fulfilled when the transmission power has reached the maximum value over a predetermined number of times during a predetermined period of time.

5. The method of claim 1, wherein the triggering parameter is indicative of an uplink signal-to-interference ratio (SIR) targeted at one of the base stations, and the reference value is indicative of a threshold value of the SIR, and wherein the triggering condition is fulfilled when the targeted SIR has exceeded the threshold value over a predetermined period of time.

6. The method claim 1, wherein the triggering parameter is indicative of a transmission power of the mobile terminal, and the reference value is indicative of a threshold value of the transmission power, and wherein the triggering condition is fulfilled when the transmission power has exceeded the threshold value and an average of the transmission power over a period of time indicates that the transmission power is capable of reaching a maximum transmission power within a predetermined period of time.

7. The method of claim 1, wherein the triggering parameter is indicative of a ratio of a received signal power to a received signal strength indicator, and the reference value is indicative of a threshold value for the receiver signal power, and wherein the triggering condition is fulfilled when the ratio has fallen below the threshold value over a predetermined period of time.

8. The method of claim 1, wherein the mobile terminal comprises at least two receivers.

9. The method of claim 1, wherein the mobile terminal comprises a single receiver.

10. The method of claim 9, wherein the first network operator has at least one radio network controller for connecting one or more base stations to the telecommunication networks, and where the second signal is conveyed from the radio network controller to the mobile terminal to activate the compressed data transmission mode in the mobile terminal.

11. The method of claim 1, wherein the first network operator operates at a first frequency and the second operator operates at a second frequency different from the first frequency in a wideband code division multiplex access mode.

12. The method of claim 1, wherein the first network operator operates in a wideband code division multiplex access (WCDMA) mode and the second network operator operates in a mode in accordance with the global system for mobile communications (GSM).

14. The system of claim 13, wherein the triggering parameter is indicative of a transmission power of the mobile terminal in the uplink, and the reference value is indicative of a threshold value for the transmission power, and wherein the triggering condition is fulfilled when the transmission power has exceeded the threshold value over a predetermined period of time.

15. The system of claim 13, wherein the triggering parameter is indicative of a transmission power in the downlink to the mobile terminal, and the reference value is indicative of a threshold value of the transmission power, and wherein the triggering condition is fulfilled when the transmission power has exceeded the threshold value over a predetermined period of time.

16. The system of claim 13, wherein the triggering parameter is indicative of a transmission power of the mobile terminal and the reference value is a maximum value of the transmission power, and wherein the triggering condition is fulfilled when the transmission power has reached the maximum value over a predetermined number of times during a predetermined period of time.

17. The system of claim 13, wherein the triggering parameter is indicative of an uplink signal-to-interference ratio (SIR) targeted at one of the base stations, and the reference value is indicative of a threshold value of the SIR, and wherein the triggering condition is fulfilled when the targeted SIR has exceeded the threshold value over a predetermined period of time.

18. The system of claim 13, wherein the triggering parameter is indicative of a transmission power of the mobile terminal, and the reference value is indicative of a threshold value of the transmission power, and wherein the triggering condition is fulfilled when the transmission power has exceeded the threshold value and an average of the transmission power over a period of time indicates that the transmission power is capable of reaching a maximum transmission power within a predetermined period of time.

19. The system of claim 13, wherein the triggering parameter is indicative of a ratio of a received signal power to a received signal strength indicator, and the reference value is indicative of a threshold value for the receiver signal power, and wherein the triggering condition is fulfilled when the ratio has fallen below the threshold value over a predetermined period of time.

20. The system of claim 13, wherein the mobile terminal comprises at least two receivers.

21. The system of claim 13, wherein the mobile terminal comprises a single receiver.

22. The system of claim 21, wherein the first network operator has at least one radio network controller for connecting one or more base stations to the telecommunication networks, and where the second signal is conveyed from the radio network controller to the mobile terminal to activate the compressed data transmission mode in the mobile terminal.

23. The system of claim 13, wherein the first network operator operates at a first frequency and the second operator operates at a second frequency different from the first frequency in a wideband code division multiplex access mode.

24. The system of claim 13, wherein the first network operator operates in a wideband code division multiplex access (WCDMA) mode and the second network operator operates in a mode in accordance with the global system for mobile communications (GSM).

13. A system for triggering a handover event in telecommunication networks having a plurality of base stations operated by a plurality of network operators each having one or more frequency carriers, wherein the handover event is used in a frequency division multiplex (FDD) mode of a mobile terminal capable of communicating with one or more base stations of the telecommunication networks over corresponding uplink and downlink, for allowing the mobile terminal to move from the radio coverage area of a first frequency carrier to the radio coverage area of a second frequency carrier while maintaining communication with one or more base stations, wherein the handover event is performed based on signal strength and/or signal quality measurement, said system comprising:

means, communicative with the mobile terminal, for obtaining a triggering parameter and providing a first signal indicative of the triggering parameter; and

means, responsive to the first signal, for determine whether the triggering parameter has fulfilled a triggering condition regarding a reference value, for providing a second signal when the triggering parameter has fulfilled the triggering condition for starting the signal strength and/or signal quality measurement.