Apparatus and Method for Cell Reselection in a Radio Access Network

Abstract

A method for cell reselection from a serving cell to another cell in a radio access network covering a geographical area divided into a plurality of cells, the method comprising: attempting to reselect to a first other cell with a higher rank value than the serving cell; setting up a channel on the first other cell and initiating a completion period; conditional on the completion period expiring before the first other cell is identified as being a suitable cell, receiving cell measurements for cells and creating a cell ranking list of the cells based on rank values of the cells; conditional on a second other cell having a higher rank value than the serving cell or first other cell, attempting to reselect to the second other cell.

1 . A method for cell reselection from a serving cell to another cell in a radio access network covering a geographical area divided into a plurality of cells, the method comprising:
 attempting to reselect to a first other cell with a higher rank value than the serving cell;   setting up a channel on the first other cell and initiating a completion period;   conditional on the completion period expiring before the first other cell is identified as being a suitable cell, receiving cell measurements for cells and creating a cell ranking list of the cells based on rank values of the cells;   conditional on a second other cell having a higher rank value than the serving cell or first other cell, attempting to reselect to the second other cell.   
     
     
         2 . A method according to  claim 1 , further comprising:
 conditional on the first other cell having the highest rank value, reading system information from the first other cell and checking that the first other cell is a suitable cell.   
     
     
         3 . A method according to  claim 1 , further comprising:
 conditional on the serving cell having the highest rank value, receiving cell measurements for cells, creating a cell ranking list of the cells based on rank values of the cells and checking that the serving cell has the highest rank value.   
     
     
         4 . A method according to  claim 1 , wherein the cell measurements are intra-frequency, inter-frequency and inter RAT cell measurements. 
     
     
         5 . A method according to  claim 1 , wherein the rank values are calculated for the serving cell and neighbouring cells. 
     
     
         6 . A method according to  claim 1 , wherein the channel is PCCPCH. 
     
     
         7 . A method according to  claim 1 , wherein the completion period is a predetermined period of time. 
     
     
         8 . A method according to  claim 1 , wherein the completion period is defined by the occurrence of predetermined number of defined events. 
     
     
         9 . A mobile communication device for use in a radio access network covering a geographical area divided into a plurality of cells, comprising:
 one or more processors;   a wireless transceiver coupled to the one or more processors;   memory coupled to the one or more processors;   the one or more processors being operative to:   attempt to reselect to a first other cell with a higher rank value than the serving cell;   set up a channel on the first other cell and initiating a completion period;   receive, conditional on the completion period expiring before the first other cell is identified as being a suitable cell, cell measurements for cells and create a cell ranking list of the cells based on rank values of the cells;   attempt, conditional on a second other cell having a higher rank value than the serving cell or first other cell, to reselect to the second other cell.   
     
     
         10 . A mobile communication device according to  claim 9 , wherein the one or more processors are further operative to:
 read, conditional on the first other cell having the highest rank value, system information from the first other cell and check that the first other cell is a suitable cell.   
     
     
         11 . A mobile communication device according to  claim 9 , wherein the one or more processors are further operative to:
 create, conditional on the serving cell having the highest rank value, receiving cell measurements for cells, a cell ranking list of the cells based on rank values of the cells and check that the serving cell has the highest rank value.   
     
     
         12 . A mobile communication device according to  claim 9 , wherein the cell measurements are intra-frequency, inter-frequency and inter RAT cell measurements. 
     
     
         13 . A mobile communication device according to  claim 9 , wherein the rank values are calculated for the serving cell and neighbouring cells. 
     
     
         14 . A mobile communication device according to  claim 9 , wherein the channel is PCCPCH. 
     
     
         15 . A mobile communication device according to  claim 9 , wherein the completion period is a predetermined period of time. 
     
     
         16 . A mobile communication device according to  claim 9 , wherein the completion period is defined by the occurrence of predetermined number of defined events. 
     
     
         17 . A computer program product comprising program code stored on a computer readable medium, the program code arranged, in use, to:
 attempt to reselect to a first other cell with a higher rank value than the serving cell;   set up a channel on the first other cell and initiating a completion period;   receive, conditional on the completion period expiring before the first other cell is identified as being a suitable cell, cell measurements for cells and create a cell ranking list of the cells based on rank values of the cells;   attempt, conditional on a second other cell having a higher rank value than the serving cell or first other cell, to reselect to the second other cell.