Method and apparatus for selecting a radio link control protocol data unit size

Abstract

A method and apparatus are used to create RLC PDUs in advance of the E-TFC selection for the MAC PDU that will include this or these RLC PDU(s). The apparatus may be configured to pre-generate RLC PDUs for transmission in a later TTI. This approach avoids large peak processing requirement due to the tight delay constraint if any RLC PDU to be included into a MAC PDU had to be created after the determination of the size of this MAC PDU, i.e. after E-TFC selection. The method and apparatus maintain an approximate match between the size of an RLC PDU and the size of the MAC PDU it is included into. Maintaining this approximate match ensures that the RLC PDU error rate due to HARQ residual errors remains low. This approach may be designed as “semi-radio aware” or “radio-aware with delay”.

1 - 55 . (canceled) 
     
     
         56 . A method for use in a wireless transmit/receive unit (WTRU), the method comprising:
 choosing a size of a data field of an RLC PDU to be multiplexed into a MAC-i PDU or a MAC-is PDU to match a maximum amount of data allowed to be transmitted by a current grant for a current transmission time interval (TTI); and   pre-generating the RLC PDU for transmission in a later TTI.   
     
     
         57 . The method of  claim 56 , comprising determining that there is a sufficient amount of data available for transmission. 
     
     
         58 . The method of  claim 56 , wherein the RLC PDU is pre-generated based on a condition that an amount of data in one or more outstanding pre-generated RLC PDUs for a logic channel is less than a predetermined limit for the current grant. 
     
     
         59 . The method of  claim 58 , wherein the predetermined limit corresponds to a factor multiplied by the maximum amount of data allowed to be transmitted by the current grant for the current TTI. 
     
     
         60 . The method of  claim 56 , wherein the amount of data allowed to be transmitted is based on a number of bits of a currently selected enhanced dedicated channel (E-DCH) transport format combination (E-TFC). 
     
     
         61 . The method of  claim 56 , wherein the current grant is a scheduled grant or a non-scheduled grant on a condition that the data belongs to a logical channel mapped to a scheduled MAC-d flow or a non-scheduled MAC-d flow. 
     
     
         62 . A wireless transmit/receive unit (WTRU) comprising:
 a processor configured to at least:   choose a size of a data field of an RLC PDU to be multiplexed into a MAC-i PDU or a MAC-is PDU to match a maximum amount of data allowed to be transmitted by a current grant for a current transmission time interval (TTI); and   pre-generate the RLC PDU for transmission in a later TTI.   
     
     
         63 . The WTRU of  claim 62 , wherein the processor is configured to determine that there is a sufficient amount of data available for transmission. 
     
     
         64 . The WTRU of  claim 62 , wherein the RLC PDU is pre-generated based on a condition that an amount of data in one or more outstanding pre-generated RLC PDUs for a logic channel is less than a predetermined limit for the current grant. 
     
     
         65 . The WTRU of  claim 64 , wherein the predetermined limit corresponds to a factor multiplied by the maximum amount of data allowed to be transmitted by the current grant for the current TTI. 
     
     
         66 . The WTRU of  claim 62 , wherein the amount of data allowed to be transmitted is based on a number of bits of a currently selected enhanced dedicated channel (E-DCH) transport format combination (E-TFC). 
     
     
         67 . The WTRU of  claim 62 , wherein the current grant is a scheduled grant or a non-scheduled grant on a condition that the data belongs to a logical channel mapped to a scheduled MAC-d flow or a non-scheduled MAC-d flow.