Alternate transmission scheme for high speed packet access (HSPA)

Abstract

Post-hard handover processing in a Time Division—Synchronous Code Division Multiple Access (TD-SCDMA) network may be improved to allow operation of High Speed Packet Access (HSPA) in hard handover. For example, uplink synchronization may be completed concurrent with HSPA to quickly resume HSPA operation in hard handovers. User Equipment (UE) may receive downlink data while completing uplink synchronization. In another example, a unique SYNC_UL code may be assigned to a UE for hard handover. The unique SYNC_UL code allows Node Bs of the TD-SCDMA network to know which UE is performing hard handover. When a Node B is receiving the unique SYNC_UL, the Node B may begin to allocate UL data grants. After receiving UL data from the UE, the Node B may resume High Speed Downlink Packet Access (HSDPA).

What is claimed is: 
     
       1. A method for performing a handover in a Time Division—Synchronous Code Division Multiple Access (TD-SCDMA) network, comprising:
 receiving an uplink synchronization code unique to a user equipment (UE) from a source Node B (NB) of the TD-SCDMA network; 
 performing uplink synchronization with a target Node B (NB) of the TD-SCDMA network after changing both downlink and uplink channels from the source NB to the target NB to stop high speed data communication including high speed downlink data from the source NB and high speed uplink data to the source NB at an activation time specified by the TD-SCDMA network and communicated to the UE, the activation time indicating a time during which handover of the high speed data communication with the target NB occurs; 
 receiving a data uplink grant assigning network resources for resuming sending uplink data and receiving high speed downlink data from the target NB before completion of the uplink synchronization, the data uplink grant allocated to the UE based at least in part on the uplink synchronization code unique to the UE, the uplink data sent to the target NB and the high speed downlink data from the target NB associated with the high speed data communication handed over from the source NB. 
 
     
     
       2. The method of  claim 1 , further comprising transmitting a message to the target NB after completion of the uplink synchronization, wherein the message indicates completion of the handover. 
     
     
       3. A computer program product for performing a handover in a Time Division—Synchronous Code Division Multiple Access (TD-SCDMA) network, comprising:
 a non-transitory computer-readable medium comprising: 
 code to receive an uplink synchronization code unique to a user equipment (UE) from a source Node B (NB) of the TD-SCDMA network; 
 code to perform uplink synchronization with a target Node B (NB) of the TD-SCDMA network after changing both downlink and uplink channels from the source NB to the target NB to stop high speed data communication including high speed downlink data from the source NB and high speed uplink data to the source NB at an activation time specified by the TD-SCDMA network and communicated to the UE, the activation time indicating a time during which handover of the high speed data communication with the target NB occurs; and 
 code to receive a data uplink grant assigning network resources for resuming sending uplink data and to receive high speed downlink data from the target NB before completion of the uplink synchronization, the data uplink grant allocated to the UE based at least in part on the uplink synchronization code unique to the UE, the uplink data sent to the target NB and the high speed downlink data from the target NB associated with the high speed data communication handed over from the source NB. 
 
     
     
       4. The computer program product of  claim 3 , wherein the medium further comprises code to transmit a message to the target NB after completion of the uplink synchronization indicating completion of the handover. 
     
     
       5. An apparatus for performing a handover in a Time Division—Synchronous Code Division Multiple Access (TD-SCDMA) network, comprising:
 at least one processor; and 
 a memory coupled to the at least one processor, wherein the at least one processor is configured: 
 to receive an uplink synchronization code unique to a user equipment (UE) from a source Node B (NB) of the TD-SCDMA network; 
 to perform uplink synchronization with a target Node B (NB) of the TD-SCDMA network after changing both downlink and uplink channels from the source NB to the target NB to stop high speed data communication including high speed downlink data from the source NB and high speed uplink data to the source NB at an activation time specified by the TD-SCDMA network and communicated to the UE, the activation time indicating a time during which handover of the high speed data communication with the target NB occurs; and 
 to receive a data uplink grant assigning network resources for resuming sending uplink data and to receive high speed downlink data from the target NB before completion of the uplink synchronization, the data uplink grant allocated to the UE based at least in part on the uplink synchronization code unique to the UE, the uplink data sent to the target NB and the high speed downlink data from the target NB associated with the high speed data communication handed over from the source NB. 
 
     
     
       6. The apparatus of  claim 5 , wherein the at least one processor is further configured to transmit a message to the target NB after completion of the uplink synchronization indicating completion of the handover. 
     
     
       7. An apparatus for performing a handover in a Time Division—Synchronous Code Division Multiple Access (TD-SCDMA) network, comprising:
 means for receiving an uplink synchronization code unique to a user equipment (UE) from a source Node B (NB) of the TD-SCDMA network; 
 means for performing uplink synchronization with a target Node B (NB) of the TD-SCDMA network after changing both downlink and uplink channels from the source NB to the target NB to stop high speed data communication including high speed downlink data from the source NB and high speed uplink data to the source NB at an activation time specified by the TD-SCDMA network and communicated to the UE, the activation time indicating a time during which handover of the high speed data communication with the target NB occurs; and 
 means for receiving a data uplink grant assigning network resources for resuming sending uplink data and for receiving high speed downlink data from the target NB before completion of the uplink synchronization, the data uplink grant allocated to the UE based at least in part on the uplink synchronization code unique to the UE, the uplink data sent to the target NB and the high speed downlink data from the target NB associated with the high speed data communication handed over from the source NB. 
 
     
     
       8. The apparatus of  claim 7 , further comprising means for transmitting a message to the target NB after completion of the uplink synchronization, wherein the message indicates completion of the handover. 
     
     
       9. A method for performing a handover in a Time Division—Synchronous Code Division Multiple Access (TD-SCDMA) network, comprising:
 receiving an uplink synchronization code unique to a User Equipment (UE) from a source Node B (NB) of the TD-SCDMA network; 
 changing both downlink and uplink channels from the source NB to a target NB to stop high speed data communication including high speed downlink data from the source NB and high speed uplink data to the source NB at an activation time specified by the TD-SCDMA network and communicated to the UE, the activation time indicating a time during which handover of the high speed data communication with the target NB occurs; 
 transmitting the uplink synchronization code to the target NB of the TD-SCDMA network after the activation time in accordance with an uplink synchronization; 
 receiving a data uplink grant assigning network resources for resuming sending uplink data and receiving high speed downlink data from the target NB before completion of the uplink synchronization, the data uplink grant allocated to the UE based at least in part on the uplink synchronization code unique to the UE; and 
 resuming high speed data communication including sending uplink data and receiving high speed downlink data from the target NB before completion of the uplink synchronization, the high speed data communication with the target NB associated with the high speed data communication handed over from the source NB. 
 
     
     
       10. The method of  claim 9 , further comprising:
 receiving a synchronization acknowledgement; and 
 transmitting a message to the target NB, the message indicating completion of the handover. 
 
     
     
       11. The method of  claim 9 , wherein the uplink synchronization code comprises one of a set of synchronization codes for the handover. 
     
     
       12. A computer program product for performing a handover in a Time Division—Synchronous Code Division Multiple Access (TD-SCDMA) network, comprising:
 a non-transitory computer-readable medium comprising: 
 code to receive an uplink synchronization code unique to a User Equipment (UE) from a source Node B (NB) of the TD-SCDMA network; 
 code to change both downlink and uplink channels from the source NB to a target NB to stop high speed data communication including high speed downlink data from the source NB and high speed uplink data to the source NB at an activation time specified by the TD-SCDMA network and communicated to the UE, the activation time indicating a time during which handover of the high speed data communication to the target NB occurs; 
 code to transmit the uplink synchronization code to the target NB of the TD-SCDMA network after the activation time in accordance with an uplink synchronization; 
 code to receive a data uplink grant assigning network resources for resuming sending uplink data and receiving high speed downlink data from the target NB before completion of the uplink synchronization, the data uplink grant allocated to the UE based at least in part on the uplink synchronization code unique to the UE; and 
 code to resume high speed data communication including sending uplink data and receiving high speed downlink data from the target NB before completion of the uplink synchronization, the high speed data communication with the target NB associated with the high speed data communication handed over from the source NB. 
 
     
     
       13. The computer program product of  claim 12 , wherein the medium further comprises:
 code to receive a synchronization acknowledgement; and 
 code to transmit a message to the target NB, the message indicating completion of the handover. 
 
     
     
       14. The computer program product of  claim 12 , wherein the uplink synchronization code comprises one of a set of synchronization codes for the handover. 
     
     
       15. An apparatus for performing a handover in a Time Division—Synchronous Code Division Multiple Access (TD-SCDMA) network, the apparatus comprising:
 at least one processor; and a memory coupled to the at least one processor, wherein the at least one processor is configured: 
 to receive an uplink synchronization code unique to a User Equipment (UE) from a source Node B (NB) of the TD-SCDMA network; 
 to change both downlink and uplink channels from the source NB to a target NB to stop high speed data communication including high speed downlink data from the source NB and high speed uplink data to the source NB at an activation time specified by the TD-SCDMA network and communicated to the UE, the activation time indicating a time during which handover of the high speed data communication to the target NB occurs; 
 to transmit the uplink synchronization code to the target NB of the TD-SCDMA network after the activation time in accordance with an uplink synchronization; 
 to receive a data uplink grant assigning network resources for resuming sending uplink data and receiving high speed downlink data from the target NB before completion of the uplink synchronization, the data uplink grant allocated to the UE based at least in part on the uplink synchronization code unique to the UE; and 
 to resume high speed data communication including sending uplink data and receiving high speed downlink data from the target NB before completion of the uplink synchronization, the high speed data communication with the target NB associated with the high speed data communication handed over from the source NB. 
 
     
     
       16. The apparatus of  claim 15 , wherein the at least one processor is further configured:
 to receive a synchronization acknowledgement; and 
 to transmit a message to the target NB, the message indicating completion of the handover. 
 
     
     
       17. The apparatus of  claim 15 , wherein the uplink synchronization code is unique to the UE for the handover. 
     
     
       18. An apparatus for performing a handover in a Time Division—Synchronous Code Division Multiple Access (TD-SCDMA) network, comprising:
 means for receiving an uplink synchronization code unique to a User Equipment (UE) from a source Node B (NB) of the TD-SCDMA network; 
 means for changing both downlink and uplink channels from the source NB to a target NB to stop high speed data communication including high speed downlink data from the source NB and high speed uplink data to the source NB at an activation time specified by the TD-SCDMA network and communicated to the UE, the activation time indicating a time during which handover of the high speed data communication to the target NB occurs; 
 means for transmitting the uplink synchronization code to the target NB of the TD-SCDMA network after the activation time in accordance with an uplink synchronization; 
 means for receiving a data uplink grant assigning network resources for resuming sending uplink data and receiving high speed downlink data from the target NB before completion of the uplink synchronization, the data uplink grant allocated to the UE based at least in part on the uplink synchronization code unique to the UE; and 
 means for resuming high speed data communication including sending uplink data and receiving high speed downlink data from the target NB before completion of the uplink synchronization, the high speed data communication with the target NB associated with the high speed data communication handed over from the source NB. 
 
     
     
       19. The apparatus of  claim 18 , further comprising:
 means for receiving a synchronization acknowledgement; and 
 means for transmitting a message to the target NB, the message indicating completion of the handover. 
 
     
     
       20. The apparatus of  claim 18 , wherein the uplink synchronization code is unique to the UE for the handover.