Method and system for retransmission

Abstract

The present invention relates to retransmissions in a communications system. A method and system of reducing uplink retransmission delay of a radio communications system by introducing an uplink MAC ARQ layer of Node B is disclosed. Further, a MAC PDU data indicator for soft combining control in Node B and RLC PDU reordering is introduced.

1 . A method of reducing impact of transmission errors by means of a retransmission protocol, utilizing a retransmission loop involving packet radio transmissions from user equipment to a control element connected to one or more radio base stations, wherein the user equipment radio transmissions are received at one or more radio base stations for forwarding to the control element, the base station acknowledging, positively or negatively, transmissions from the user equipment and the control element acknowledging, positively or negatively, transmissions forwarded to it.  
     
     
         2 . The method according to  claim 1 , wherein for a process of retransmission, if same transmitted packet information content is received more than once, the received transmissions are combined.  
     
     
         3 . The method according to  claim 2 , wherein successive received packet transmissions of the same information content are combined in the base station prior to determining whether or not the radio base station should acknowledge the transmitted information content.  
     
     
         4 . The method according to  claim 2 , wherein whether or not the packet information content is the same is determined by means of a new data indicator.  
     
     
         5 . The method according to  claim 4 , wherein the new data indicator, accompanying packet information, is transmitted on a reliable control channel.  
     
     
         6 . The method according to  claim 2 , wherein the process is identified by means of a process identity.  
     
     
         7 . The method according to  claim 6 , wherein the process identity, accompanying packet information, is transmitted on a reliable control channel.  
     
     
         8 . The method according to  claim 1 , wherein the control element reorders received packets.  
     
     
         9 . The method according to  claim 8 , wherein the received packets are reordered into sequential order.  
     
     
         10 . The method according to  claim 9 , wherein the sequential order is determined from RLC sequence number.  
     
     
         11 . The method according to  claim 9 , wherein the sequential order is determined from MAC sequence number.  
     
     
         12 . The method according to  claim 1 , wherein the method reduces delay of uplink transmissions, the delay being associated with the retransmissions.  
     
     
         13 . A signal format for uplink transmissions from user equipment to radio base station of a radio communications system, wherein the signal format comprises signal elements allowing radio base station reception combining and acknowledgment of successive received transmissions concerning same data in uplink direction prior to forwarding received transmissions, the signal elements comprising: 
 process identity,    new data indicator, and    payload,    wherein the new data indicator indicates whether or not payload data of a process with identity as indicated by the process identity element has been transmitted previously.    
     
     
         14 . The signal format according to  claim 13 , wherein the process identity and new data indicator elements are more strongly protected by a forward error control code than payload.  
     
     
         15 . The signal format according to  claim 13 , wherein the process identity and new data indicator elements are transmitted on a control channel in synchronism with transmissions of the payload element.  
     
     
         16 . The signal format according to  claim 15 , wherein the control channel is a shared control channel of a UMTS or WCDMA system.  
     
     
         17 . The signal format according to  claim 15 , wherein the control channel is a dedicated control channel of a UMTS or WCDMA system.  
     
     
         18 . The signal format according to  claim 13 , wherein the payload element comprising an integer number of radio link control protocol data units (RLC PDUs).  
     
     
         19 . The signal format according to  claim 13 , wherein the process identity, new data indicator and payload elements are arranged for uplink transmission in a transmission time interval shorter than 10 milliseconds.  
     
     
         20 . The signal format according to clam  19 , wherein the process identity, new data indicator and payload elements are arranged for uplink transmission in a transmission time interval shorter than 4 milliseconds.  
     
     
         21 . A radio network controller of a radio communications system, comprising: 
 receive means for receiving one or more transmissions originated in a UE in uplink direction from one or more radio base stations where the one or more transmissions in uplink direction have been pre-detected according to an ARQ protocol,    receive means, for receiving first protocol data units,    buffering means, for buffering received first protocol data units,    segmentation means, for segmenting received first protocol data units into second protocol data units,    reassemble means, for reassembling second protocol data units into service data units,    transfer means, for transferring service data units, and    reordering means, for reordering first or second protocol data units.    
     
     
         22 . The radio network controller according to  claim 21 , further comprising: 
 processing means, and    transmit means,    the processing means being arranged to verify second protocol data units according to an error detecting code and the transmit means transmitting positive or negative acknowledgments depending on whether or not the second protocol data unit is detected to be erroneous.    
     
     
         23 . The radio network controller according to  claim 21 , wherein the reordering means rearranges the second protocol data units according to an RLC sequence number.  
     
     
         24 . The radio network controller according to  claim 21 , further comprising receive means arranged for receiving first protocol data units concerning a particular connection from a plurality of first protocol data senders.  
     
     
         25 . The radio network controller according to  claim 21 , wherein the first protocol data units are MAC PDUs.  
     
     
         26 . The radio network controller according to  claim 21 , wherein the second protocol data units are RLC PDUs.  
     
     
         27 . The radio network controller according to  claim 21 , wherein the radio network controller is a radio network controller of a UMTS or WCDMA system.  
     
     
         28 . A radio base station, comprising: 
 receive means, for receiving one or more first protocol data units,    a protocol entity, for processing first protocol data units, and    transmit means, for transmitting acknowledgments and for forwarding of first protocol data units.    
     
     
         29 . The radio base station according to  claim 28 , further comprising: 
 buffering means, for buffering one or more first protocol data units.    
     
     
         30 . The radio base station according to  claim 28 , wherein the protocol entity is arranged for verifying one or more first protocol data units according to a forward error control code, and depending on the outcome positively or negatively acknowledging to an uplink transmitting entity received first one or more protocol data units.  
     
     
         31 . The radio base station according to  claim 28 , further comprising means for combining received first protocol data units, the protocol entity being arranged to verify the combined protocol data unit according to a forward error control code and depending on the outcome positively or negatively acknowledging to an uplink transmitting entity the latest received protocol data unit of the combination.  
     
     
         32 . The radio base station according to  claim 31 , wherein the first protocol data units with same process identity are combined according to a received new data indicator.  
     
     
         33 . The radio base station according to  claim 28 , wherein the first protocol data units are MAC PDUs.  
     
     
         34 . The radio base station according to  claim 28 , wherein the radio base station is a radio base station of a UMTS or WCDMA system.  
     
     
         35 . A user equipment apparatus of a radio communications system, comprising: 
 assemble means for assembling one or more second protocol data units into one or more first protocol data units,    buffering means for buffering first protocol data units,    transmit means for transmitting first protocol data units according to an ARQ protocol,    receive means for receiving one or more acknowledgments of first protocol data units, and    receive means for receiving one or more acknowledgments of second protocol data units.    
     
     
         36 . The user equipment apparatus according to  claim 35 , wherein the transmit means is arranged to retransmit one or more first protocol data units if negatively acknowledged or not positively acknowledged within a predetermined time.  
     
     
         37 . The user equipment apparatus according to  claim 35 , further comprising buffering means arranged to release buffer space of one or more first protocol data units if positively acknowledged or not negatively acknowledged within a predetermined time.  
     
     
         38 . The user equipment apparatus according to  claim 35 , further comprising transmit means being arranged to transmit first protocol data units in transmission time intervals shorter than 10 milliseconds.  
     
     
         39 . The user equipment apparatus according to  claim 38 , further comprising transmit means arranged to transmit first protocol data units in transmission time intervals shorter than 4 milliseconds.  
     
     
         40 . The user equipment according to  claim 35 , wherein the first protocol data units are MAC PDUs.  
     
     
         41 . The user equipment according to  claim 35 , wherein the second protocol data units are RLC PDUs.  
     
     
         42 . The user equipment apparatus according to  claim 35 , wherein the user equipment apparatus is user equipment of a UMTS or WCDMA system.  
     
     
         43 - 46 . (canceled)  
     
     
         47 - 48 . (canceled)