Method and apparatus for assisted serving cell configuration in a heterogeneous network architecture

Abstract

Methods, systems and apparatus are provided for camping, assisted serving cell addition or removal, and discontinuous reception (DRX) in networks having a macro cell and at least one assisted serving cell. In other aspects, enhancements to Layer 1 channels and uplink timing alignments are provided in networks having a macro cell and at least one assisted serving cell. In further aspects, assisted serving cell Layer 2 architecture and transport channels are provided in networks having a macro cell and at least one assisted serving cell. In further aspects, collaborated HARQ solutions are provided in networks having a macro cell and at least one assisted serving cell.

The invention claimed is: 
     
       1. A method for adding or changing to an assisted serving cell for a user equipment, the method comprising:
 receiving, at a macro cell acting as a serving cell for the user equipment, an inter-frequency measurement report from the user equipment; 
 sending, from the macro cell, a preparation message to the assisted serving cell; 
 receiving, at the macro cell, an acknowledgement from the assisted serving cell; 
 providing, from the macro cell, an assisted serving cell activation message to the user equipment indicating the assisted serving cell is to act as an additional serving cell for the user equipment and is to provide user plane (U-plane) data communications with the user equipment; 
 receiving, at the macro cell, an activation complete message from the user equipment; and 
 sending, from the macro cell to a serving gateway or packet data node gateway, a path switch message to switch user plane data communications of the user equipment to the assisted serving cell, the macro cell remaining a serving cell for the user equipment for providing at least control plane data communications with the user equipment. 
 
     
     
       2. The method of  claim 1 , wherein the receiving the inter-frequency measurement report is in response to the macro cell sending a configuration message to the user equipment to perform inter-frequency measurements. 
     
     
       3. The method of  claim 2 , wherein the configuration message is sent only when the user equipment is close to the assisted serving cell. 
     
     
       4. The method of  claim 1 , wherein the assisted serving cell activation message contains at least one of a dedicated random access preamble and a cell radio network temporary identifier for the assisted serving cell. 
     
     
       5. The method of  claim 1 , wherein the acknowledgement from the assisted serving cell contains radio bearer reconfiguration information for the user equipment in the assisted serving cell. 
     
     
       6. The method of  claim 5 , further comprising forwarding a radio bearer configuration message to the user equipment from the macro cell. 
     
     
       7. The method of  claim 1 , wherein the sending the path switch message further comprises providing the path switch message to switch a user-plane data path from the serving gateway or packet data node gateway to the assisted serving cell from a former assisted serving cell. 
     
     
       8. The method of  claim 1 , further comprising deactivating a former assisted serving cell. 
     
     
       9. A macro cell enabled for adding or changing to an assisted serving cell for a user equipment, the macro cell comprising:
 a processor; and 
 a communications subsystem, 
 
       wherein the macro cell acts as a serving cell for the user equipment and is enabled to:
 receive an inter-frequency measurement report from the user equipment; 
 send a preparation message to the assisted serving cell; 
 receive an acknowledgement from the assisted serving cell; 
 provide an assisted serving cell activation message to the user equipment indicating the assisted serving cell is to act as an additional serving cell for the user equipment and is to provide user plane (U-plane) data communications with the user equipment; 
 receive an activation complete message from the user equipment; and 
 send, from the macro cell to a serving gateway or packet data node gateway, a path switch message to switch user plane data communications of the user equipment to the assisted serving cell, the macro cell remaining a serving cell for the user equipment for providing at least control plane data communications with the user equipment. 
 
     
     
       10. The macro cell of  claim 9 , wherein the macro cell is enabled to receive the inter-frequency measurement report in response to the macro cell sending a configuration message to the user equipment to perform inter-frequency measurements. 
     
     
       11. The macro cell of  claim 10 , wherein the configuration message is sent only when the user equipment is close to the assisted serving cell. 
     
     
       12. The macro cell of  claim 9 , wherein the assisted serving cell activation message contains at least one of a dedicated random access preamble and a cell radio network temporary identifier for the assisted serving cell. 
     
     
       13. The macro cell of  claim 9 , wherein the acknowledgement from the assisted serving cell contains radio bearer reconfiguration information for the user equipment in the assisted serving cell. 
     
     
       14. The macro cell of  claim 13 , wherein the macro cell is further enabled to forward a radio bearer configuration message to the user equipment from the macro cell. 
     
     
       15. The macro cell of  claim 9 , wherein the macro cell is enabled to send the path switch message to switch a user-plane data path from the serving gateway or packet data node gateway to the assisted serving cell from a former assisted serving cell. 
     
     
       16. The macro cell of  claim 9 , wherein the macro cell is enabled to deactivate a former assisted serving cell.