Frequency layer convergence method for mbms

Abstract

A method to control cell selection and/or re-selection in a communication system comprising a plurality of cells with which terminal devices may communicate, the method including the steps of: determining that a terminal device is to start a session for a certain service, the service using a reception frequency; based on that determination, changing at least one cell selection and/or re-selection parameter in respect of the terminal device with the effect that a subsequent cell selection and/or re-selection performed by the device would favor cells that use the reception frequency used in the service session over other cells.

1 . A method to control cell selection and/or re-selection in a communication system comprising a plurality of cells with which terminal devices may communicate, the method comprising:
 determining that a terminal device is to start a session for a multimedia broadcast multicast service (MBMS), the multimedia broadcast multicast service using a preferred frequency layer; and   changing, based on the determination that the terminal device is to start the session, a cell selection priority parameters of a cell in the plurality of cells using the preferred frequency layer for the MBMS from normal values, the cell selection priority parameter being for prioritizing the cell in the plurality of cells to be selected or reselected for the terminal device.   wherein changing the cell selection priority parameters comprises at least one of at least triggering immediate selection or reselection of the cell and making selection or reselection more likely for the cell.   
     
     
         2 . The method of  claim 1 , further comprising selecting which of a plurality of cell selection or reselection parameters is to be changed based on the cell selection priority parameter. 
     
     
         3 . The method of  claim 1 , wherein changing the cell selection priority parameter comprises receiving data identifying a new value for the cell selection priority parameter from the MBMS. 
     
     
         4 . The method of  claim 3 , wherein the data is received by means of a unicast session control start message or by means of a broadcast system information data message. 
     
     
         5 . The method of  claim 1 , wherein changing the cell selection priority parameter comprises setting a parameter that reduces the responsiveness of the terminal device to high mobility triggers. 
     
     
         6 . A terminal device comprising:
 a processor;   a memory coupled to the processor, the memory configured to store computer program code that, when executed by the processor, cause the terminal device to:
 determine that a terminal device is to start a session for a multimedia broadcast multicast service (MBMS), the multimedia broadcast multicast service using a preferred frequency layer; and 
 change, based on the determination that the terminal device is to start the session, a cell selection priority parameter of a cell in the plurality of cells using the preferred frequency layer for the MBMS from normal values, the cell selection priority parameter being for prioritizing the cell in the plurality of cells to be selected or reselected for the terminal device, 
   wherein changing the cell selection priority parameter comprises at least one of at least triggering immediate selection or reselection of the cell and making selection or reselection more likely for the cell.   
     
     
         7 . The terminal device of  claim 6 , wherein the terminal is further caused to select which of a plurality of cell selection or reselection parameters is to be changed based on the cell selection priority parameter. 
     
     
         8 . The terminal device of  claim 6 , wherein changing the cell selection priority parameter comprises receiving data identifying a new value for the cell selection priority parameter from the MBMS. 
     
     
         9 . The terminal device of  claim 8 , wherein the terminal device is configured to receive the data by one of a unicast session control start message and a broadcast system information data message. 
     
     
         10 . The terminal device of  claim 6 , wherein the terminal is further caused to change the cell selection priority parameter by setting a parameter that reduces the responsiveness of the terminal device to high mobility triggers. 
     
     
         11 . A non-transitory computer-readable memory adapted for use by a terminal device in requesting and using a multimedia broadcast multicast service, the non-transitory computer-readable memory used to direct the terminal device to perform the steps of:
 determining that a terminal device is to start a session for a multimedia broadcast multicast service (MBMS), the multimedia broadcast multicast service using a preferred frequency layer; and   changing, based on the determination that the terminal device is to start the session, a cell selection priority parameter of a cell in the plurality of cells using the preferred frequency layer for the MBMS from normal values, the cell selection priority parameter being for prioritizing the cell in the plurality of cells to be selected or reselected for the terminal device,   wherein changing the cell selection priority parameter comprises at least one of at least triggering immediate selection or reselection of the cell and making selection or reselection more likely for the cell.   
     
     
         12 . The non-transitory computer-readable memory of  claim 11 , further comprising selecting which of a plurality of cell selection or reselection parameters is to be changed based on the cell selection priority parameter. 
     
     
         13 . The non-transitory computer-readable memory of  claim 11 , wherein changing the cell selection priority parameter comprises receiving data identifying a new value for the cell selection priority parameter from the MBMS. 
     
     
         14 . The non-transitory computer-readable memory of  claim 13 , wherein the data is received by means of a unicast session control start message or by means of a broadcast system information data message. 
     
     
         15 . The non-transitory computer-readable memory of  claim 11 , wherein changing the cell selection priority parameter comprises setting a parameter that reduces the responsiveness of the terminal device to high mobility triggers.