Method and apparatus for supporting segmentation of packets for uplink transmission

Abstract

A method and apparatus for segmenting medium access control (MAC) service data units (SDUs) creates enhanced MAC-es PDUs in the enhanced MAC-e/es sub-layer by concatenating MAC SDUs received from the logical channels. An enhanced transport format combination (E-TFC) selection entity controls the concatenation of MAC SDUs into enhanced MAC-es PDUs. When a MAC SDU is received that is too large to fit into a selected enhanced MAC-es PDU payload, a segmentation entity segments the MAC SDU such that the MAC SDU segment fills the remaining payload available in the selected enhanced MAC-es PDU. The enhanced MAC-es PDU is then assigned a transmission sequence number (TSN) and multiplexed with other enhanced MAC-es PDUs to create a single enhanced MAC-e PDU that is transmitted on the E-DCH in the next transmission time interval (TTI). A HARQ entity stores and, if necessary retransmits the enhanced MAC-e PDU when a transmission error occurs.

What is claimed is: 
     
         1 . A wireless transmit/receive unit (WTRU) comprising:
 a medium access control (MAC) entity for an enhanced dedicated channel (E-DCH), the MAC entity comprising:
 one or more segmentation entities configured to segment a MAC protocol data unit (PDU) on a condition that the MAC PDU is too large to fit in a payload size, wherein there is one segmentation entity for each logical channel; 
 a multiplexing and a transmission sequence number (TSN) setting entity configured to concatenate multiple MAC PDUs and multiplex one or more of the concatenated MAC PDUs into a MAC PDU to be transmitted in a next transmission time interval (TTI), wherein the MAC PDU to be transmitted in the next TTI includes a TSN and a segmentation description field that provides an indication of a segmentation status of the one or more MAC PDUs in the concatenated and multiplexed MAC PDU; 
 an enhanced transport format combination (E-TFC) selection entity configured to control the multiplexing and TSN setting entity; and 
 a hybrid automatic retransmission request (HARQ) entity configured to store and transmit the MAC PDU in a payload, wherein the transmitted MAC PDU includes the concatenated and multiplexed MAC PDUs. 
   
     
     
         2 . The WTRU of  claim 1 , wherein the E-TFC selection entity in the MAC entity is further configured to instruct the at least one segmentation entity that the MAC PDU is too large to fit in the payload size. 
     
     
         3 . The WTRU of  claim 1 , wherein the segmentation description field indicates whether a segment of a MAC PDU is included in the concatenated and multiplexed MAC PDU. 
     
     
         4 . The WTRU of  claim 1 , wherein the segmentation description field indicates whether additional segments of a MAC PDU are expected in a next concatenated and multiplexed MAC PDU. 
     
     
         5 . The WTRU of  claim 1 , wherein the segmentation description field indicates whether the concatenated and multiplexed MAC PDU include a segment of a MAC PDU. 
     
     
         6 . The WTRU of  claim 1 , wherein the at least one segmentation entity further comprises at least one buffer configured to store one or more remaining MAC SDU segments not included in the payload. 
     
     
         7 . The WTRU of  claim 6 , wherein the at least one buffer is associated with the one or more segmentation entities. 
     
     
         8 . The WTRU of  claim 1 , wherein the multiple MAC PDUs have different sizes. 
     
     
         9 . The WTRU of  claim 1 , wherein the segmented MAC PDU is a MAC for dedicated channel (MAC-d) PDU. 
     
     
         10 . The WTRU of  claim 1 , wherein the transmitted MAC PDU is an enhanced PDU used for transmitting data on the E-DCH. 
     
     
         11 . A method for use in a wireless transmit/receive unit (WTRU) having a medium access control (MAC) entity for an enhanced dedicated channel (E-DCH), the method comprising:
 segmenting a MAC protocol data unit (PDU) on a condition that the MAC PDU is too large to fit in a payload size;   concatenating multiple MAC PDUs and multiplexing one or more of the concatenated MAC PDUs into a MAC PDU to be transmitted in a next transmission time interval (TTI), wherein the MAC PDU to be transmitted in the next TTI includes a transmission sequence number (TSN) and a segmentation description field that provides an indication of a segmentation status of the one or more MAC PDUs in the concatenated and multiplexed MAC PDU; and   storing and transmitting the concatenated and multiplexed MAC PDUs in a payload, wherein the transmitted MAC PDU includes the concatenated and multiplexed MAC PDUs.   
     
     
         12 . The method of  claim 11 , further comprising determining that the MAC PDU is too large to fit in the payload size. 
     
     
         13 . The method of  claim 11 , wherein the segmentation description field indicates whether a segment of a MAC PDU is included in the concatenated and multiplexed MAC PDU. 
     
     
         14 . The method of  claim 11 , wherein the segmentation description field indicates whether additional segments of a MAC PDU are expected in a next concatenated and multiplexed MAC PDU. 
     
     
         15 . The method of  claim 11 , wherein the segmentation description field indicates whether the concatenated and multiplexed MAC PDU include a segment of a MAC PDU. 
     
     
         16 . The method of  claim 11 , further comprising storing one or more remaining MAC SDU segments not included in the payload. 
     
     
         17 . The method of  claim 11 , wherein the multiple MAC PDUs have different sizes. 
     
     
         18 . The method of  claim 11 , wherein the segmented MAC PDU is a MAC for dedicated channel (MAC-d) PDU. 
     
     
         19 . The method of  claim 11 , wherein the transmitted MAC PDU is an enhanced PDU used for transmitting data on the E-DCH.