Cell range expansion elasticity control

Abstract

In some aspects, a method for carrying out load balancing between cells in a heterogeneous network includes measuring loads within macro clusters in the network. The method additionally includes identifying one or more macro clusters experiencing unbalanced load conditions, and sending balancing indicators to one or more cells in the identified macro cluster(s). In other aspects, a method for carrying out load balancing in a heterogeneous network includes reporting cell loads within a macro cluster, and monitoring for balancing indicators. The method further includes responding to a balancing indicator by iteratively adjusting a value of an individual cell offset for a cell until one or more conditions is satisfied. Example conditions include accomplishment of handover, to or from the cell, of one or more low mobility User Equipment (UE), and making a determination that the value of the individual cell offset has reached a threshold prohibiting further adjustment.

What is claimed is: 
     
         1 . A method for carrying out load balancing in a heterogeneous network, comprising:
 reporting cell loads within a macro cluster;   monitoring for one or more balancing indicators; and   responding to a balancing indicator by iteratively adjusting a value of an individual cell offset for a cell until at least one of:
 handover, to or from the cell, of one or more low mobility User Equipment (UE) can be accomplished; or 
 a determination is made that the value of the individual cell offset has reached at least one threshold prohibiting further adjustment. 
   
     
     
         2 . The method of  claim 1 , wherein reporting the cell loads includes reporting at least one of: resource block utilization, subframe utilization, or a number of Radio Resource Control (RRC) connections. 
     
     
         3 . The method of  claim 1 , wherein responding to the balancing indicator includes responding to a macro-to-pico offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a macro cell to report an identity of a pico cell if a reference signal receive power of the pico cell is greater than a reference signal receive power of the macro cell after adjustment thereof by an individual cell offset for the pico cell;   adjusting the individual cell offset for the pico cell to increase a cell range of the pico cell when none of the low mobility UEs reporting the identity of the macro cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the pico cell.   
     
     
         4 . The method of  claim 1 , wherein responding to the balancing indicator includes responding to a pico-to-macro offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a pico cell to report an identity of a macro cell if a reference signal receive power of the macro cell is greater than a reference signal receive power of the pico cell after adjustment thereof by an individual cell offset for the pico cell;   adjusting the individual cell offset for the pico cell to decrease a cell range of the pico cell when none of the low mobility UEs reporting the identity of the macro cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the macro cell.   
     
     
         5 . The method of  claim 1 , wherein responding to the balancing indicator includes responding to a macro-to-macro offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a macro cell to report an identity of a neighbor macro cell if a reference signal receive power of the neighbor macro cell is greater than a reference signal receive power of the macro cell after adjustment thereof by an individual cell offset for the neighbor macro cell;   adjusting the individual cell offset for the neighbor macro cell to decrease a cell range of the neighbor macro cell when none of the low mobility UEs reporting the identity of the neighbor macro cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the neighbor macro cell.   
     
     
         6 . The method of  claim 1 , wherein responding to the balancing indicator includes responding to a pico-to-pico offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a pico cell to report an identity of a neighbor pico cell if a reference signal receive power of the neighbor pico cell is greater than a reference signal receive power of the pico cell after adjustment thereof by an individual cell offset for the neighbor pico cell;   adjusting the individual cell offset for the neighbor pico cell to increase the cell range of the neighbor pico cell when none of the low mobility UEs reporting the identity of the neighbor pico cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the neighbor pico cell.   
     
     
         7 . An apparatus for carrying out load balancing in a heterogeneous network, comprising:
 means for reporting cell loads within a macro cluster;   means for monitoring for one or more balancing indicators; and   means for responding to a balancing indicator by iteratively adjusting a value of an individual cell offset for a cell until at least one of:
 handover, to or from the cell, of one or more low mobility User Equipment (UE) can be accomplished; or 
 a determination is made that the value of the individual cell offset has reached at least one threshold prohibiting further adjustment. 
   
     
     
         8 . The apparatus of  claim 7 , wherein means for reporting the cell loads includes means for reporting at least one of: resource block utilization, subframe utilization, or a number of Radio Resource Control (RRC) connections. 
     
     
         9 . The apparatus of  claim 7 , wherein the means for responding to the balancing indicator includes means for responding to a macro-to-pico offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a macro cell to report an identity of a pico cell if a reference signal receive power of the pico cell is greater than a reference signal receive power of the macro cell after adjustment thereof by an individual cell offset for the pico cell;   adjusting the individual cell offset for the pico cell to increase a cell range of the pico cell when none of the low mobility UEs reporting the identity of the macro cell; and   configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the pico cell.   
     
     
         10 . The apparatus of  claim 7 , wherein the means for responding to the balancing indicator includes means for responding to a pico-to-macro offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a pico cell to report an identity of a macro cell if a reference signal receive power of the macro cell is greater than a reference signal receive power of the pico cell after adjustment thereof by an individual cell offset for the pico cell;   adjusting the individual cell offset for the pico cell to decrease a cell range of the pico cell when none of the low mobility UEs reporting the identity of the macro cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the macro cell.   
     
     
         11 . The apparatus of  claim 7 , wherein the means for responding to the balancing indicator includes means for responding to a macro-to-macro offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a macro cell to report an identity of a neighbor macro cell if a reference signal receive power of the neighbor macro cell is greater than a reference signal receive power of the macro cell after adjustment thereof by an individual cell offset for the neighbor macro cell;   adjusting the individual cell offset for the neighbor macro cell to decrease a cell range of the neighbor macro cell when none of the low mobility UEs reporting the identity of the neighbor macro cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the neighbor macro cell.   
     
     
         12 . The apparatus of  claim 7 , wherein the means for responding to the balancing indicator includes means for responding to a pico-to-pico offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a pico cell to report an identity of a neighbor pico cell if a reference signal receive power of the neighbor pico cell is greater than a reference signal receive power of the pico cell after adjustment thereof by an individual cell offset for the neighbor pico cell;   adjusting the individual cell offset for the neighbor pico cell to increase the cell range of the neighbor pico cell when none of the low mobility UEs reporting the identity of the neighbor pico cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the neighbor pico cell.   
     
     
         13 . A computer program, stored on a non-transitory computer-readable medium, comprising program code for causing at least one computer to:
 report cell loads within a macro cluster;   monitor for one or more balancing indicators; and   respond to a balancing indicator by iteratively adjusting a value of an individual cell offset for a cell until at least one of:
 handover, to or from the cell, of one or more low mobility User Equipment (UE) can be accomplished; or 
 a determination is made that the value of the individual cell offset has reached at least one threshold prohibiting further adjustment. 
   
     
     
         14 . The computer program of  claim 13 , wherein the program code for causing a computer to report the cell loads includes program code for causing the at least one computer to report at least one of: resource block utilization, subframe utilization, or a number of Radio Resource Control (RRC) connections. 
     
     
         15 . The computer program of  claim 13 , wherein the program code for causing a computer to respond to the balancing indicator includes program code for causing the at least one computer to respond to a macro-to-pico offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a macro cell to report an identity of a pico cell if a reference signal receive power of the pico cell is greater than a reference signal receive power of the macro cell after adjustment thereof by an individual cell offset for the pico cell;   adjusting the individual cell offset for the pico cell to increase a cell range of the pico cell when none of the low mobility UEs reporting the identity of the macro cell;   configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the pico cell.   
     
     
         16 . The computer program of  claim 13 , wherein the program code for causing a computer to respond to the balancing indicator includes program code for causing the at least one computer to respond to a pico-to-macro offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a pico cell to report an identity of a macro cell if a reference signal receive power of the macro cell is greater than a reference signal receive power of the pico cell after adjustment thereof by an individual cell offset for the pico cell;   adjusting the individual cell offset for the pico cell to decrease a cell range of the pico cell when none of the low mobility UEs reporting the identity of the macro cell;   configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the macro cell.   
     
     
         17 . The computer program of  claim 13 , wherein the program code for causing a computer to respond to the balancing indicator includes program code for causing the at least one computer to respond to a macro-to-macro offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a macro cell to report an identity of a neighbor macro cell if a reference signal receive power of the neighbor macro cell is greater than a reference signal receive power of the macro cell after adjustment thereof by an individual cell offset for the neighbor macro cell;   adjusting the individual cell offset for the neighbor macro cell to decrease a cell range of the neighbor macro cell when none of the low mobility UEs reporting the identity of the neighbor macro cell;   configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the neighbor macro cell.   
     
     
         18 . The computer program of  claim 13 , wherein the program code for causing a computer to respond to the balancing indicator includes program code for causing a computer to respond to a pico-to-pico offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a pico cell to report an identity of a neighbor pico cell if a reference signal receive power of the neighbor pico cell is greater than a reference signal receive power of the pico cell after adjustment thereof by an individual cell offset for the neighbor pico cell;   adjusting the individual cell offset for the neighbor pico cell to increase the cell range of the neighbor pico cell when none of the low mobility UEs reporting the identity of the neighbor pico cell;   configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the neighbor pico cell.   
     
     
         19 . A network component of a heterogeneous network, the network component comprising:
 a memory; and   at least one processor coupled to said memory, and configured to:
 report cell loads within a macro cluster; 
 monitor for one or more balancing indicators; and 
 respond to a balancing indicator by iteratively adjusting a value of an individual cell offset for a cell until at least one of:
 handover, to or from the cell, of one or more low mobility User Equipment (UE) can be accomplished; or 
 a determination is made that the value of the individual cell offset has reached at least one threshold prohibiting further adjustment. 
 
   
     
     
         20 . The network component of  claim 20 , wherein said at least one processor is configured to report the cell loads by reporting at least one of: resource block utilization, subframe utilization, or a number of Radio Resource Control (RRC) connections. 
     
     
         21 . The network component of  claim 20 , wherein said at least one processor is configured to respond to a macro-to-pico offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a macro cell to report an identity of a pico cell if a reference signal receive power of the pico cell is greater than a reference signal receive power of the macro cell after adjustment thereof by an individual cell offset for the pico cell;   adjusting the individual cell offset for the pico cell to increase a cell range of the pico cell when none of the low mobility UEs reporting the identity of the macro cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the pico cell.   
     
     
         22 . The network component of  claim 20 , wherein said at least one processor is configured to respond to a pico-to-macro offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a pico cell to report an identity of a macro cell if a reference signal receive power of the macro cell is greater than a reference signal receive power of the pico cell after adjustment thereof by an individual cell offset for the pico cell;   adjusting the individual cell offset for the pico cell to decrease a cell range of the pico cell when none of the low mobility UEs reporting the identity of the macro cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the macro cell.   
     
     
         23 . The network component of  claim 20 , wherein said at least one processor is configured to respond to a macro-to-macro offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a macro cell to report an identity of a neighbor macro cell if a reference signal receive power of the neighbor macro cell is greater than a reference signal receive power of the macro cell after adjustment thereof by an individual cell offset for the neighbor macro cell;   adjusting the individual cell offset for the neighbor macro cell to decrease a cell range of the neighbor macro cell when none of the low mobility UEs reporting the identity of the neighbor macro cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the neighbor macro cell.   
     
     
         24 . The network component of  claim 20 , wherein said at least one processor is configured to respond to a pico-to-pico offload indicator by:
 configuring one or more measurement reports for one or more low mobility UEs served by a pico cell to report an identity of a neighbor pico cell if a reference signal receive power of the neighbor pico cell is greater than a reference signal receive power of the pico cell after adjustment thereof by an individual cell offset for the neighbor pico cell;   adjusting the individual cell offset for the neighbor pico cell to increase the cell range of the neighbor pico cell when none of the low mobility UEs reporting the identity of the neighbor pico cell, and configuring additional measurement reports for the one or more low mobility UEs; and   selecting one of the UEs reporting the identity, and requesting a handover of the selected UE to the neighbor pico cell.