Association biasing for a heterogeneous network (HetNet)

Abstract

A method for association biasing at a mobile device in a heterogeneous network (HetNet) is disclosed. The method can include the mobile device receiving coordination set information from a macro node in the HetNet. The coordination set information can include at least one low power node (LPN) identifier of at least one LPN. The mobile device can receive a request from the macro node to apply a specified reference signal (RS) biasing. The mobile device can apply the specified RS biasing to an LPN RS measurement derived from a LPN RS received from an LPN having an LPN identifier in the received coordination set information. The mobile device can associate the mobile device with the LPN when the LPN RS measurement with the specified RS biasing exceeds an association threshold.

What is claimed is: 
     
       1. A system for association biasing at a mobile device in a heterogeneous network (HetNet), comprising:
 a means for receiving coordination set information from a macro node in the HetNet at the mobile device, wherein the coordination set information includes at least one low power node (LPN) identifier of at least one LPN; 
 a means for receiving a request from the macro node at the mobile device to apply a specified reference signal (RS) biasing; 
 a means for applying the specified RS biasing at the mobile device to an LPN RS measurement derived from a LPN RS received from an LPN having an LPN identifier in the received coordination set information; and 
 a means for associating the mobile device with the LPN when the LPN RS measurement with the specified RS biasing exceeds an association threshold. 
 
     
     
       2. The system of  claim 1 , wherein the LPN RS measurement includes a measurement selected from the group consisting of a reference signal received power (RSRP), a reference signal received quality (RSRQ), and combinations thereof. 
     
     
       3. The system of  claim 1 , wherein the specified RS biasing has a range greater than 0 decibel (dB) to about 16 dB. 
     
     
       4. The system of  claim 1 , wherein the means for associating the mobile device with the LPN further comprises a means for associating the mobile device with the LPN when the LPN RS measurement with the specified RS biasing exceeds a macro node RS measurement by a predetermined amount. 
     
     
       5. The system of  claim 4 , further comprising prior to applying the specified RS biasing at the mobile device:
 a means for measuring a LPN RS from the LPN to generate the LPN RS measurement; and 
 a means for measuring a macro node RS from the macro node to generate the macro node RS measurement. 
 
     
     
       6. The system of  claim 1 , wherein at least one LPN in a coordinating set has coordinated signaling with the macro node in the coordinating set. 
     
     
       7. The system of  claim 1 , wherein the means for associating with the LPN further comprises a means for sending a re-association request from the mobile device to the macro node to associate with the LPN, wherein the re-association request instructs the macro node to offload communication with the mobile device to the LPN. 
     
     
       8. The system of  claim 7 , wherein the re-association request includes a LPN RS measurement taken by the mobile device. 
     
     
       9. The system of  claim 1 , wherein the means for associating with the LPN transfers communication from the macro node to the LPN. 
     
     
       10. A mobile device in a heterogeneous network (HetNet), comprising:
 a transceiver configured to receive coordination set information from a macro node in the HetNet and receive a request from the macro node to apply a specified reference signal (RS) biasing, wherein the coordination set information includes at least one low power node (LPN) identifier of at least one LPN having coordinated signaling with the macro node; and 
 a processing module configured to apply the specified RS biasing to a LPN RS measurement when a LPN has a LPN identifier in the received coordination set information, and trigger an association with the LPN when the LPN RS measurement with the specified RS biasing exceeds an association threshold. 
 
     
     
       11. The mobile device of  claim 10 , wherein the LPN RS measurement includes a measurement selected from the group consisting of a reference signal received power (RSRP), a reference signal received quality (RSRQ), and combinations thereof. 
     
     
       12. The mobile device of  claim 10 , wherein the specified RS biasing has a range greater than 0 decibel (dB) to about 16 dB. 
     
     
       13. The mobile device of  claim 10 , wherein the association threshold is based on a macro node RS measurement. 
     
     
       14. The mobile device of  claim 13 , wherein the processing module is further configured to measure a LPN RS to generate a LPN RS measurement and measure a macro node RS to generate a macro node RS measurement. 
     
     
       15. The mobile device of  claim 10 , wherein the mobile device includes a user equipment (UE) with an antenna, a touch sensitive display screen, a speaker, a microphone, a graphics processor, an application processor, internal memory, a non-volatile memory port, or combinations thereof. 
     
     
       16. A macro node in a heterogeneous network (HetNet) having a coordination set including at least one low power node (LPN), comprising:
 a wireless transceiver configured to transmit coordination set information to a mobile device and transmit a request to the mobile device in the HetNet to apply a specified reference signal (RS) biasing to a LPN RS measurement derived from a LPN RS received from the at least one LPN in the coordination set, wherein the coordination set information includes a LPN identifier for the at least one LPN having coordinated signaling with the macro node; and 
 a backhaul link transceiver configured to communicate with the at least one LPN and transfer an association with the mobile device to one of the at least one LPNs in the coordination set when a LPN RS measurement with the specified RS biasing exceeds an association threshold. 
 
     
     
       17. The macro node of  claim 16 , wherein the specified RS biasing has a range greater than 0 decibel (dB) to about 16 dB. 
     
     
       18. The macro node of  claim 16 , further comprising a processing module configured for implementing an enhanced inter-cell interference coordination (eICIC), coordinated multi-point (CoMP), or combination of thereof for the nodes in the coordination set when the specified RS biasing is requested. 
     
     
       19. The macro node of  claim 16 , wherein the coordinated signaling includes X2 signaling or backhaul link signaling via a wired connection, a wireless connection, or an optical fiber connection. 
     
     
       20. The macro node of  claim 16 , wherein the macro node includes a macro evolved Node B (macro-eNB) and the LPN includes a micro-eNB, a pico-eNB, a femto-eNB, or a home eNB (HeNB).