Prioritizing Radio Access Technologies For Measurement

Abstract

A prioritized measurement list is stored in a memory, and each entry in the prioritized measurement list defines a unique combination of frequency layer and radio access technology for a serving cell and for neighbor cells. Based on at least signal strength of the serving cell, there is selected, from a neighbor list according to the prioritized measurement list, a set of entries for measuring according to a selection rule. The selection rule provides: for the case in which the signal strength of the serving cell is relatively high, the selected set is a first set and represents higher priority ones of the prioritized measurement list; and for the case in which the signal strength of the serving cell is relatively low, the selected set is a second set and represents lower priority ones of the prioritized measurement list.

1 . An apparatus comprising 
       at least one processor; and 
       at least one memory including computer program code; 
       in which the at least one memory with the computer program code is configured, with the at least one processor, to cause the apparatus at least to:
 store in the at least one memory a prioritized measurement list, each entry in the prioritized measurement list defining a unique combination of frequency layer and radio access technology for a serving cell and for neighbor cells; and 
 based on at least signal strength of the serving cell, select from a neighbor list according to the prioritized measurement list a set of entries for measuring according to a selection rule; 
 
       wherein the selection rule provides:
 for the case in which the signal strength of the serving cell is relatively high, the selected set is a first set and represents higher priority ones of the prioritized measurement list; and 
 for the case in which the signal strength of the serving cell is relatively low, the selected set is a second set and represents lower priority ones of the prioritized measurement list. 
 
     
     
         2 . The apparatus according to  claim 1 , in which there are at least two radio access technologies represented in the prioritized measurement list, and the selection rule provides that all frequency layers belonging to the radio access technology having a highest priority or alternatively a lowest priority are excluded from the selected second set. 
     
     
         3 . The apparatus according to  claim 2 , wherein:
 the radio access technologies EUTRAN, UTRAN and GERAN are each represented in the prioritized measurement list, GERAN has the lowest priority and EUTRAN has the highest priority.   
     
     
         4 . The apparatus according to  claim 1 , in which the apparatus comprises a user equipment which generates the prioritized measurement list at least in part using at least one of:
 signaling received from the serving cell which provides relative priority information for the radio access technologies represented by the entries of the prioritized measurement list; and   at least one radio access technology specific absolute priority list which is received from the serving cell.   
     
     
         5 . The apparatus according to  claim 4 , in which the relative priority information is expressed as weighting factors received which are specific for each of the radio access technologies represented by the entries of the prioritized measurement list. 
     
     
         6 . The apparatus according to  claim 5 , in which the at least one memory with the computer program code is configured with the at least one processor to cause the apparatus at least further to:
 take measurements of cells corresponding to the selected set of entries according to a scaling frequency which spreads the entries of the selected set across measurement occasions according to the weighting factors.   
     
     
         7 . The apparatus according to  claim 1 , in which the apparatus comprises a user equipment which is configured to generate the prioritized measurement list from the neighbor list anytime there are at least three radio access technologies represented in the neighbor list. 
     
     
         8 . The apparatus according to  claim 1 , in which the apparatus comprises a user equipment which wirelessly receives the prioritized measurement list in system information broadcast by the serving cell or from dedicated signaling received from the serving cell. 
     
     
         9 . A method, comprising:
 storing in a computer readable memory a prioritized measurement list, each entry in the prioritized measurement list defining a unique combination of frequency layer and radio access technology for a serving cell and for neighbor cells; and   based on at least signal strength of the serving cell, selecting from a neighbor list according to the prioritized measurement list a set of entries for measuring according to a selection rule;   
       wherein the selection rule provides:
 for the case in which the signal strength of the serving cell is relatively high, the selected set is a first set and represents higher priority ones of the prioritized measurement list; and 
 for the case in which the signal strength of the serving cell is relatively low, the selected set is a second set and represents lower priority ones of the prioritized measurement list. 
 
     
     
         10 . The method according to  claim 9 , in which there are at least two radio access technologies represented in the prioritized measurement list, and the selection rule provides that all frequency layers belonging to the radio access technology having a highest priority or alternatively a lowest priority are excluded from the selected second set. 
     
     
         11 . The method according to  claim 10 , wherein:
 the radio access technologies EUTRAN, UTRAN and GERAN are each represented in the prioritized measurement list, GERAN has the lowest priority and EUTRAN has the highest priority.   
     
     
         12 . The method according to  claim 10 , in which the method is executed by a user equipment and the method further comprises the user equipment generating the prioritized measurement list at least in part using at least one of:
 signaling received from the serving cell which provides relative priority information for the radio access technologies represented by the entries of the prioritized measurement list; and   at least one radio access technology specific absolute priority list which is received from the serving cell.   
     
     
         13 . The method according to  claim 12 , in which the relative priority information is expressed as weighting factors which are specific for each of the radio access technologies represented by the entries of the prioritized measurement list. 
     
     
         14 . The method according to  claim 13 , in which method further comprises:
 taking measurements of cells corresponding to the selected set of entries according to a scaling frequency which spreads the entries of the selected set across measurement occasions according to the weighting factors.   
     
     
         15 . The method according to  claim 9 , in which the method is executed by a user equipment and the method further comprises the user equipment generating the prioritized measurement list from the neighbor list anytime there are at least three radio access technologies represented in the neighbor list. 
     
     
         16 . The method according to  claim 9 , in which the method is executed by a user equipment and the method further comprises the user equipment wirelessly receiving the prioritized measurement list in system information broadcast by the serving cell or from dedicated signaling received from the serving cell. 
     
     
         17 . A memory tangibly storing a computer program that is executable by at least one processor, in which the computer program comprises:
 code for storing in a computer readable memory a prioritized measurement list, each entry in the prioritized measurement list defining a unique combination of frequency layer and radio access technology for a serving cell and for neighbor cells; and   code for, based on at least signal strength of the serving cell, selecting from a neighbor list according to the prioritized measurement list a set of entries for measuring according to a selection rule;   wherein the selection rule provides:   for the case in which the signal strength of the serving cell is relatively high, the selected set is a first set and represents higher priority ones of the prioritized measurement list; and   for the case in which the signal strength of the serving cell is relatively low, the selected set is a second set and represents lower priority ones of the prioritized measurement list.   
     
     
         18 . The memory according to  claim 17 , in which there are at least two radio access technologies represented in the prioritized measurement list, and the selection rule provides that all frequency layers belonging to the radio access technology having a highest priority or alternatively a lowest priority are excluded from the selected second set 
     
     
         19 . The memory according to  claim 18 , wherein:
 the radio access technologies EUTRAN, UTRAN and GERAN are each represented in the prioritized measurement list, GERAN has the lowest priority and EUTRAN has the highest priority.   
     
     
         20 . The memory according to  claim 18 , further comprising code for generating the prioritized measurement list at least in part using at least one of:
 signaling received from the serving cell which provides relative priority information for the radio access technologies represented by the entries of the prioritized measurement list; and   at least one radio access technology specific absolute priority list which is received from the serving cell.