Method and wireless transmit/receive unit for supporting an enhanced uplink dedicated channel inter-node-b serving cell change

Abstract

A wireless communication method and system for supporting an enhanced uplink dedicated channel (EU-DCH) inter-Node-B serving cell change. The system includes at least one wireless transmit/receive unit (WTRU) for transmitting data blocks, a target Node-B, a source Node-B and a serving radio network controller (S-RNC). The S-RNC includes a re-ordering buffer which stores data blocks correctly received from the WTRU. The S-RNC informs the target Node-B of a need for an EU-DCH inter-Node-B serving cell change from the source Node-B to the target Node-B. A medium access control (MAC) entity that handles EU-DCH functionalities is set up in the target Node-B. Hybrid automatic repeat request (HARQ) processes and transmission sequence numbers (TSNs) are not reset at the WTRU. Using a new data indicator, the WTRU transmits a data block to the target Node-B that was previously transmitted to the source Node-B, but was not correctly received by the source Node-B.

1 . A wireless transmit/receive unit (WTRU) comprising:
 a receiver configured to receive first scheduling information from a first serving cell and to not receive the first scheduling information from non-serving cells;   a transmitter configured based on the received first scheduling information to transmit enhanced uplink data as protocol data units (PDUs) using a HARQ process to at least the first serving cell; wherein each of the PDUs includes a transmission sequence number;   wherein the receiver is further configured to receive a radio resource control (RRC) message indicating a change to a second serving cell for enhanced uplink;   wherein the receiver is further configured to receive second scheduling resources from the second serving cell and not from non-serving cells; and   wherein the transmitter is further configured in response to the change to the second serving cell, to retransmit unacknowledged PDUs transmitted prior to the change to the second serving cell to at least the second serving cell; wherein the transmission sequence numbers of each of the retransmitted PDUs is unchanged from the respective originally transmitted PDU.   
     
     
         2 . The WTRU of  claim 1  wherein the non-serving cells after the change to the second serving cell include the first serving cell. 
     
     
         3 . The WTRU of  claim 1  wherein the HARQ process is not reset in response to the change to the second serving cell. 
     
     
         4 . The WTRU of  claim 1  wherein the transmitter is further configured to not change a transmission sequence numbering in response to the change to the second serving cell. 
     
     
         5 . A method comprising:
 receiving, by a wireless transmit/receive unit (WTRU), first scheduling information from a first serving cell and to not receive the first scheduling information from non-serving cells;   based on the received scheduling information, transmitting by the WTRU, enhanced uplink data as protocol data units (PDUs) using a HARQ process to at least the first serving cell; wherein each of the PDUs includes a transmission sequence number;   receiving, by the WTRU, a radio resource control (RRC) message indicating a change to a second serving cell for enhanced uplink;   receiving, by the WTRU in response to the change to the second serving cell, second scheduling resources from the second serving cell and not from non-serving cells; and   in response to the change to the second serving cell, retransmitting, by the WTRU, unacknowledged PDUs transmitted prior to the change to the second serving cell to at least the second serving cell; wherein the transmission sequence numbers of each of the retransmitted PDUs is unchanged from the respective originally transmitted PDU.   
     
     
         6 . The method of  claim 5  wherein the non-serving cells after the change to the second serving cell include the first serving cell. 
     
     
         7 . The method of  claim 5  wherein the HARQ process is not reset in response to the change to the second serving cell. 
     
     
         8 . The method of  claim 5  wherein a transmission sequence numbering is not changed in response to the change to the second serving cell. 
     
     
         9 . A Node-B comprising:
 a transmitting and receiving components configured to implement a medium access control (MAC) entity for a serving cell; wherein the MAC entity transmits first scheduling information via the serving cell to a wireless transmit/receive unit (WTRU); wherein non-serving cells do not transmit the first scheduling information;   the transmitting and receiving components are further configured in response to the transmitted first scheduling information, to receive enhanced uplink data as protocol data units (PDUs) using a HARQ process; wherein each of the PDUs includes a transmission sequence number;   the transmitting and receiving components are further configured to forward the received PDUs using the MAC entity to a radio network controller without reordering the received PDUs;   wherein the Node-B receives a message indicating that the first serving cell is to change to a non-serving cell; the transmitting and receiving components are further configured in response to the change to a non-serving cell to not transmit first scheduling information to the WTRU.   
     
     
         10 . The Node-B of  claim 9  wherein the message indicating that the first serving cell is to change to a non-serving cell is an TUB message.