Method and apparatus for controlling a handover between utra R6 cells and R7 cells
A method and apparatus for controlling an optimization of handover procedures between universal terrestrial radio access (UTRA) release 6 (R6) cells and UTRA release 7 (R7) cells are disclosed. When a wireless transmit/receive unit (WTRU) is moving between an R6 cell and an R7 cell, or between R7 cells, a handover is initiated from a source Node-B to a target Node-B. In the R7 cell, the enhanced medium access control (MAC) functionality including flexible radio link control (RLC) protocol data unit (PDU) size and high speed MAC (MAC-hs) segmentation and multiplexing of different priority queues are supported. After the handover, a MAC layer and/or an RLC layer are reconfigured or reset based on functionality supported by the target Node-B.
1. A wireless transmit/receive unit (WTRU) comprising:
a radio resource control (RRC) unit; and
a medium access control (MAC) unit comprising:
a hybrid automatic repeat request (HARQ) hard buffer; a re-ordering queue including a re-ordering release timer and an enhanced high speed MAC (MAC-ehs) re-ordering timer;
a reassembly unit; and
a logical channel identifier (LCH-ID) demultiplexing unit, the MAC unit configured to:
receive a MAC-ehs reset message from the RRC unit, wherein the MAC-ehs reset message includes at least one of a downlink high speed MAC (MAC-hs) reset indicator and an indication of MAC-hs configuration;
flush the HARQ soft buffer for all configured HARQ processes;
stop the re-ordering release timer and the MAC-ehs re-ordering timer, wherein the re-ordering queue performs re-ordering of received MAC-ehs protocol data units (PDUs) using at least one variable;
set the timers and the variable to their initial values;
deliver all re-ordering PDUs in the re-ordering queue to the reassembly unit, wherein the reassembly unit performs reassembly of segmented MAC-ehs service data units (SDUs), delivers successfully reassembled MAC-ehs SDUs to the LCH-ID demultiplexing unit, which delivers the complete MAC SDUs to the correct logical channel or MAC flow, discards stored MAC-ehs SDU segments from the reassembly unit; and
flush the re-ordering queue.
2. The WTRU of claim 1 , wherein the re-ordering queue includes a plurality of re-ordering release timers and a plurality of MAC-ehs re-ordering timers.
3. The WTRU of claim 2 , wherein MAC unit is further configured to:
stop all active re-ordering release timers; and
set all re-ordering release timers to their initial values.
4. The WTRU of claim 2 , wherein the MAC unit is further configured to:
stop all active reset timers; and
set all active reset times to their initial values.
5. The WTRU of claim 2 , wherein the MAC unit is further configured to:
stop all active re-ordering release timers and set all re-ordering release timers to their initial value; and
stop all active reset timers and set all timers to their initial value.
6. A method of resetting a medium access control (MAC) unit, the method comprising:
receiving an enhanced high speed MAC (MAC-ehs) reset message from a radio resource control (RRC) unit, wherein the MAC-ehs reset message includes at least one of a downlink high speed MAC (MAC-hs) reset indicator and an indication of a DL MAC-hs configuration;
flushing a hybrid automatic repeat request (HARQ) soft buffer in the MAC unit for all configured HARQ processes;
stopping a re-ordering release timer and a MAC-ehs re-ordering timer located in a re-ordering queue of the MAC unit, wherein the re-ordering queue performs re-ordering of received MAC-ehs protocol data units (PDUs) using at least one variable and includes a plurality of re-ordering release timers and a plurality of MAC-ehs re-ordering timers;
setting the timers and the variable to their initial values;
delivering all re-ordering PDUs in the re-ordering queue to a reassembly unit located in the MAC unit;
the reassembly unit performing reassembly of segmented MAC-ehs service data units (SDUs) and delivering successfully reassembled MAC-ehs SDUs to a logical channel identifier (LCH-ID) demultiplexing unit located in the MAC unit;
the LCH-ID demultiplexing unit delivering the complete MAC SDUs to the correct logical channel or MAC flow;
flushing the re-ordering queue; and
discarding stored MAC-ehs SDU segments from the reassembly unit.
7. The method of claim 6 , wherein stopping the re-ordering release timer and the MAC-ehs reordering timer comprises:
stopping all active re-ordering release timers; and
setting all re-ordering release timers to their initial values.
8. The method of claim 6 , wherein stopping the re-ordering release timer and the MAC-ehs reordering timer comprises:
stopping all active reset timers; and
setting all active reset times to their initial values.
9. The method of claim 6 , wherein stopping the re-ordering release timer and the MAC-ehs reordering timer comprises:
stopping all active re-ordering release timers and set all re-ordering release timers to their initial value; and
stopping all active reset timers and set all timers to their initial value.