Enhanced handover procedure

• US 9,161,282 B2
• Filed: 11/14/2011
• Issued: 10/13/2015
• Est. Priority Date: 11/15/2010
• Status: Expired due to Fees

• Current Assignee: ST-Ericcson SA (Telefonaktiebolaget LM Ericsson)
• Original Assignee: ST-Ericcson SA (Telefonaktiebolaget LM Ericsson)
• Inventors: Sfar, Safouane
• Primary Examiner(s): SIVJI, NIZAR N
• Application Number:
  US13/884,725
• Publication Number:
  US 20130273917A1
• Time in Patent Office: 1,429 Days
• Field of Search: 370/236.1, 370/237, 455/436, 455/446, 4554351-4353
• US Class Current: 1/1
• CPC Class Codes: H04W 36/0094 Definition of hand-off measurement parameters
• CPC Class Codes: H04W 36/22 for handling the traffic
• 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

The invention relates to a handover method for redirecting an ongoing communication of a connected cellular device (UE) from a serving cell (SRV_C) to a target cell (TGT_C). Both cells (SRV_C, TGT_C) belong to a network. The method comprises receiving, in the connected cellular device (UE), a cell attenuation measurement, a supplemental hysteresis parameter which value depends on the load of the target cell (TGT_C), and a threshold parameter. The method comprises comparing, in the connected cellular device (UE), an additive combination of the cell attenuation measurement, of a hysteresis parameter and of the supplemental hysteresis parameter with the threshold parameter. The method comprises sending, from the connected cellular device (UE), a measurement report to the network, if the result of the comparison remains positive during a given duration. The invention also relates to a cellular device (UE) and to a computer program implementing the aforementioned method.

Claims

1. A handover method for redirecting an ongoing communication of a connected cellular device from a serving cell to a target cell, both cells belonging to a network, wherein the method comprises:

(a) receiving, in the cellular device, a cell attenuation measurement,

(b) receiving, in the cellular device, a supplemental hysteresis parameter which value depends on the load of the target cell,

(c) receiving, in the cellular device, a threshold parameter,

(d) comparing, in the cellular device, an additive combination of the cell attenuation measurement, of a hysteresis parameter and of the supplemental hysteresis parameter with the threshold parameter, and

(e) sending a measurement report from the cellular device to the network when the result of the comparison remains positive during a given duration, wherein for a serving cell attenuation measurement the result remains positive when the additive combination is below the threshold parameter and for a target cell attenuation measurement the result remains positive when the additive combination is above the threshold parameter, wherein when the result does not remain positive during a given duration the cellular device remains in the serving cell,

wherein the value of the duration in step (e) is dependent on the load of the target cell and a time to trigger (TTT) parameter.

2. The handover method according to claim 1, wherein the cell attenuation measurement is the serving cell attenuation measurement, wherein the additive combination is equal to the sum of the serving cell attenuation measurement, of the hysteresis parameter and of the supplemental hysteresis parameter, and wherein the comparison checks whether the additive combination is lower than the threshold parameter.

3. The handover method according to claim 1, wherein the cell attenuation measurement is the target cell attenuation measurement, wherein the additive combination is equal to the target cell attenuation measurement minus the hysteresis parameter minus the supplemental hysteresis parameter, and wherein the comparison checks whether the additive combination is greater than the threshold parameter.

4. The handover method according to claim 1, wherein the method comprises receiving the supplemental hysteresis parameter inside a measurement control message.

5. The handover method according to claim 1, wherein the method comprises receiving, in the cellular device, the value of the duration in step (e) inside a measurement control message.

11. A non-transitory computer readable medium comprising one or more stored sequences of instructions that are accessible to a processor and which, when executed by the processor, cause the processor to carry out the steps of claim 1.

6. A cellular device comprising a processor for redirecting an ongoing communication from a serving cell to a target cell, both cells belonging to a network, wherein the processor is set to:

(a) receive a cell attenuation measurement,

(b) receive a supplemental hysteresis parameter which value depends on the load of the target cell,

(c) receive a threshold parameter,

(d) compare an additive combination of the cell attenuation measurement, of a hysteresis parameter and of the supplemental hysteresis parameter with the threshold parameter, and

(e) send a measurement report to the network when the result of the comparison remains positive during a given duration, wherein for a serving cell attenuation measurement the result remains positive when the additive combination is below the threshold parameter and for a target cell attenuation measurement the result remains positive when the additive combination is above the threshold parameter, wherein when the result does not remain positive during a given duration the cellular device remains in the serving cell,

wherein the value of the duration in step (e) is dependent on the load of the target cell and a time to trigger (TTT) parameter.

7. The cellular device according to claim 6, wherein the cell attenuation measurement is the serving cell attenuation measurement, wherein the additive combination is equal to the sum of the serving cell attenuation measurement, of the hysteresis parameter and of the supplemental hysteresis parameter, and wherein the comparison checks whether the additive combination is lower than the threshold parameter.

8. The cellular device according to claim 6, wherein the cell attenuation measurement is the target cell attenuation measurement, wherein the additive combination is equal to the target cell attenuation measurement minus the hysteresis parameter minus the supplemental hysteresis parameter, and wherein the comparison checks whether the additive combination is greater than the threshold parameter.

9. The cellular device according to claim 6, wherein the handover module is set to receive the supplemental hysteresis parameter inside a measurement control message.

10. The cellular device according to claim 6, wherein the handover module is set to receive the value of the duration for deciding to trigger the handover inside a measurement control message.