Method and apparatus for transmitting data packets and method and apparatus for receiving data packets
The invention relates to a data packet structure for conveying data of service data units (SDU) using protocol data units (PDU). The data packet comprise a data packet payload comprising at least one protocol data unit (PDU), wherein a protocol data unit (PDU) comprises a service data unit (SDU) or a fragment of a service data unit; and a data packet header comprising an indicator (FFF,SFF) indicating whether or not the data packet payload begins with a protocol data unit (PDU) being a fragment of a service data unit and whether or not the data packet payload ends with a protocol data unit (PDU) being a fragment of a service data unit.
1. A data transmission method comprising:
segmenting or concatenating, by one or more processors, radio layer control (RLC) service data units (SDUs) to RLC protocol data units (PDUs) that fit within a size of a total size of RLC PDU(s) indicated by a lower protocol layer processor, each RLC PDU having a header and a data field;
mapping, by the one or more processors, a single two bit field including a first bit and a second bit to the header for each of the RLC PDUs, wherein a number of bits included in the single two bit field is two regardless of a number of SDUs included in the data field;
the first bit and the second bit indicating only (i) whether or not the data field of its corresponding RLC PDU begins with a segment of an RLC SDU, and (ii) whether or not the data field ends with a segment of an RLC SDU;
transmitting, by a transmitter, a data packet including one or more of the RLC PDUs.
2. The data transmission method according to claim 1 , further comprising mapping a sequence number to the header for each of the RLC PDUs.
3. The data transmission method according to claim 1 , further comprising mapping a length indicator to the header for each of the RLC PDUs.
4. A Data transmission apparatus comprising:
a processor configured to segment or concatenate radio layer control (RLC) service data units (SDUs) to RLC protocol data units (PDUs) that fit within a size of a total size of RLC PDU(s) indicated by a lower protocol layer processor, each RLC PDU having a header and a data field;
the processor being further configured to map a single two bit field including a first bit and a second bit to the header for each of the RLC PDUs, wherein a number of bits included in the single two bit field is two regardless of a number of SDUs included in the data field;
the first bit and the second bit indicate only (i) whether or not the data field of its corresponding RLC PDU begins with a segment of an RLC SDU, and (ii) whether or not the data field ends with a segment of an RLC SDU;
a transmitter configured to transmit a data packet including one or more of the RLC PDUs.
5. The data transmission apparatus according to claim 4 , wherein the processor is configured to map a sequence number to the header for each of the RLC PDUs.
6. The data transmission apparatus according to claim 4 , wherein the apparatus is a wireless terminal in a communication system.
7. The data transmission apparatus according to claim 4 , wherein the apparatus is a wireless base station in a communication system.
8. A method for receiving data packets, the method comprising the steps of:
(a) receiving and processing data packets by a receiver;
(b) detecting, in at least some of the data packets, radio layer control (RLC) protocol data units (PDUs), each RLC PDU having a header and a data field;
wherein the data field includes (i) a plurality of full service data units (SDUs), (ii) a plurality of segments of SDUs, or (iii) at least one full SDU and at least one segment of a SDU;
wherein the header includes a single two bit field with a first bit and a second bit, wherein a number of bits included in the single two bit field is two regardless of a number of SDUs included in the data field, and wherein the first bit and the second bit of the single two bit field indicate only (i) whether or not the data field begins with a segment of an SDU, and (ii) whether or not the data field ends with a segment of an SDU; and
(b) reassembling the SDUs of the received data field based on the single two bit field.
9. The method according to claim 8 , wherein the method further comprises:
buffering the (i) plurality of full SDUs, (ii) plurality of segments of SDUs, or (iii) at least one full SDU and at least one segment of an SDU of the received data field with previously received at least one full or segment of an SDU in a reception buffer.
10. An apparatus for receiving data packets, the apparatus comprising:
a receiver configured to receive data packets;
one or more processors, coupled to the receiver, configured to detect, in at least some of the data packets, radio layer control (RLC) protocol data units (PDUs), each RLC PDU having a header and a data field;
wherein the data field includes (i) a plurality of full service data units (SDUs), (ii) a plurality of segments of SDUs, or (iii) at least one full SDU and at least one segment of a SDU;
wherein the header includes a single two bit field with a first bit and a second bit, wherein a number of bits included in the single two bit field is two regardless of a number of SDUs included in the data field, and wherein the first bit and the second bit of the single two bit field indicate only (i) whether or not the data field begins with a segment of an SDU, and (ii) whether or not the data field ends with a segment of an SDU; and
wherein the one or more processors are configured to reassemble the SDUs of the received data field based on the single two bit field.
11. The apparatus according to claim 10 , wherein the apparatus further comprises a reception buffer configured to buffer the (i) plurality of full SDUs, (ii) plurality of segments of SDUs, or (iii) at least one full SDU and at least one segment of an SDU of the received data field with previously received at least one full or segment of an SDU.
12. The apparatus according to claim 10 , the apparatus is a wireless terminal in a communication system.
13. The apparatus according to claim 10 , the apparatus is a wireless base station in a communication system.