Method and apparatus for creating an enhanced medium access control packet data unit for enhanced transport format combination selection in wireless communications

Abstract

Efficient enhanced transport format combination (E-TFC) selection methods and apparatus support flexible radio link control (RLC) packet data unit (PDU) size and medium access control (MAC) layer segmentation. Methods for filling an enhanced medium access control (MAC-e) packet data unit (PDU) with data from logical channels as part of E-TFC selection are provided. In one embodiment, the E-TFC selection algorithm employs a single request from the MAC layer to the RLC layer to request the number of bits it is allowed to send for a logical channel to create enhanced MAC-e PDUs. In another embodiment, the MAC entity performs multiple requests to the RLC entity. In another embodiment, the MAC entity makes a single request to the RLC entity to create one or more enhanced MAC-e PDUs of a set size. A technique is also provided for maintaining a guaranteed bit rate (GBR) for non-scheduled data flows with variable-length headers.

What is claimed: 
     
         1 . A method for creating an enhanced medium access control (MAC-e) packet data unit (PDU) associated with enhanced transport format combination (E-TFC) selection, the method comprising:
 determining that a segment of a first radio link control (RLC) PDU associated with a first logical channel is available for transmission, wherein the segment is remaining from a previous transmission;   on a condition that a size of the segment and a corresponding header does not exceed a determined size, including the segment and the corresponding header in the enhanced MAC-e PDU;   on a condition that a size of the segment and a corresponding header exceeds the determined size re-segmenting the segment into a first sub-segment and a second sub-segment, including the first sub-segment and a corresponding header in the enhanced MAC-e PDU, and storing the second sub-segment for a next transmission; and   transmitting the enhanced MAC-e PDU.   
     
     
         2 . The method of  claim 1 , further comprising:
 on a condition that a second RLC PDU and a corresponding header are included in the enhanced MAC-e PDU, and size of the second RLC PDU and the corresponding header exceeds the determined size:   dividing the second RLC PDU into a first segment and a second segment; and   including the first segment and a corresponding header in the enhanced MAC-e PDU, and storing the remaining second segment for a next transmission.   
     
     
         3 . The method of  claim 2 , wherein the second RLC PDU is associated with the first logical channel. 
     
     
         4 . The method of  claim 2 , wherein the determined size is a minimum of a remaining available payload or a remaining granted payload. 
     
     
         5 . The method of  claim 1 , wherein the first logical channel is a highest priority logical channel. 
     
     
         6 . The method of  claim 2 , wherein the second RLC PDU and the corresponding header are included in the enhanced MAC-e PDU. 
     
     
         7 . A wireless transmit/receive unit (WTRU) comprising:
 a processor configured to at least:
 determine that a segment of a first radio link control (RLC) packet data unit (PDU) associated with a first logical channel is available for transmission, wherein the segment is remaining from a previous transmission; 
 on a condition that size of the segment and a corresponding header does not exceed a determined size, include the segment and the corresponding header in an enhanced medium access control (MAC-e) PDU; 
 on a condition that size of the segment and a corresponding header exceeds the determined size 
 re-segment the segment into a first sub-segment and a second sub-segment, including the first sub-segment and the corresponding header in the enhanced MAC-e PDU, and store the remaining second sub-segment for a next transmission; and 
   a transmitter configured to transmit the enhanced MAC-e PDU.   
     
     
         8 . The WTRU of  claim 7 , further comprising:
 on a condition that a second RLC PDU and a corresponding header are included in the enhanced MAC-e PDU, and size of the second RLC PDU and the corresponding header exceeds the determined size:   divide the second RLC PDU into a first segment and a second segment; and   include the first segment and a corresponding header in the enhanced MAC-e PDU, and storing the remaining second segment for a next transmission.   
     
     
         9 . The WTRU of  claim 8 , wherein the second RLC PDU is associated with the first logical channel. 
     
     
         10 . The WTRU of  claim 8 , wherein the determined size is a minimum of a remaining available payload or a remaining granted payload. 
     
     
         11 . The WTRU of  claim 7 , wherein the first logical channel is a highest priority logical channel. 
     
     
         12 . The WTRU of  claim 8 , wherein the second RLC PDU and the corresponding header are included in the enhanced MAC-e PDU.