Sequence number ordering in a wireless communications system

A wireless communications system that uses a layer 2 protocol data unit (PDU) having a move receiving window (MRW) request to discard at least a layer 2 service data unit (SDU), the wireless communications system comprising:

• a transmitter capable of transmitting a layer 2 MRW super-field comprising;
• a layer 2 PDU sequence number for each layer 2 SDU to be discarded, an initial sequence number arranged within the MRW super-field according to a packing algorithm;
• and a length field, the length field indicating the number of layer 2 PDU sequence numbers in the MRW super-field, a special case value is used for the length field to indicate that the MRW super-field holds a single layer 2 PDU sequence number for a single layer 2 SDU that is to be discarded and that extends beyond a transmitting window of the transmitter;
• and
• a receiver capable of receiving the transmitted MRW super-field and extracting the initial sequence number from the MRW super-field according to an extracting algorithm that corresponds to the packing algorithm and that enables identification of the initial sequence number;
• wherein the receiver assumes that the layer 2 PDU sequence numbers within MRW super-field are all sequentially on or after the initial sequence number when determining the sequential ordering of layer 2 PDUs for discarding each layer 2 SDU, and the receiver assumes the layer 2 PDU sequence number to be sequentially on or after a starting point sequence number of a receiving window of the receiver when the length field holds the special case value.

A method for determining sequential ordering of layer 2 protocol data units (PDUs) during a layer 2 move receiving window (MRW) request sent to a receiver in a wireless communications system by a transmitter to discard at least a layer 2 service data unit (SDU), the method comprising:

• building a layer 2 MRW super-field comprising a layer 2 PDU sequence number for each layer 2 SDU to be discarded, an initial sequence number arranged within the MRW super-field according to a packing algorithm, the initial sequence number being within a transmitting window of the transmitter;
• transmitting the MRW super-field to the receiver;
• extracting the initial sequence number from the MRW super-field according to an extracting algorithm corresponding to the packing algorithm to enable identification of the initial sequence number;
• assuming layer 2 PDU sequence numbers within MRW super-field are all sequentially on or after the initial sequence number when determining the sequential ordering of layer 2 PDUs for discarding each layer 2 SDU;
• and
• assuming the initial sequence number to be sequentially before an end point sequence number of the receiving window of the receiver.

A wireless communications system that uses a layer 2 protocol data unit (PDU) having a move receiving window (MRW) request to discard at least a layer 2 service data unit (SDU), the wireless communications system comprising:

• a transmitter capable of transmitting a layer 2 MRW super-field comprising;
• a layer 2 PDU sequence number for each layer 2 SDU to be discarded, an initial sequence number arranged within the MRW super-field according to a packing algorithm, the initial sequence number being within a transmitting window of the transmitter;
• and
• a receiver capable of receiving the transmitted MRW super-field and extracting the initial sequence number from the MRW super-field according to an extracting algorithm that corresponds to the packing algorithm and that enables identification of the initial sequence number;
• wherein the receiver assumes that the layer 2 PDU sequence numbers within MRW super-field are all sequentially on or after the initial sequence number when determining the sequential ordering of layer 2 PDUs for discarding each layer 2 SDU, and the receiver assumes the initial sequence number to be sequentially before an end point sequence number of the receiving window.