Communication device and method thereof for D2D communications

1. A communication device for receiving a plurality of data packets in a wireless network, at least comprising:

a control circuit;

a processor installed in the control circuit; a memory installed in the control circuit and coupled to the processor; wherein the processor is configured to execute a program code stored in memory to:

receive one or more medium access control (MAC) protocol data units (PDUs) a) from a source user equipment (UE) of the wireless network through a relay UE and a base station, and b) directly from the source UE, wherein the MAC PDUs are composed of a plurality of radio link control (RLC) PDUs and a plurality of RLC PDU segments;

demultiplex the MAC PDUs to retrieve the RLC PDUs and the RLC PDU segments based on a header field of each MAC PDU;

reorder the RLC PDUs and the RLC PDU segments and perform a duplicate detection of the RLC PDUs and the RLC PDU segments according to transmission sequence numbers (TSNs), wherein each TSN is included in a header field of each RLC PDU and each RLC PDU segment; and

reassemble the RLC PDUs and the RLC PDU segments into a plurality of RLC service data units (SDUs) using information included in the header field of each RLC PDU and each RLC PDU segment.

2. A communication device for receiving a plurality of data packets in a wireless network, at least comprising:

a control circuit;

a processor installed in the control circuit;

a memory installed in the control circuit and coupled to the processor;

wherein the processor is configured to execute a program code stored in memory to:

receive a plurality of first medium access control (MAC) protocol data units (PDUs) from a source user equipment (UE) of the wireless network through a relay UE and a base station, wherein the first MAC PDUs are composed of a plurality of RRLC (Relay RLC) PDUs which are protocol data units of a protocol layer between the MAC layer and the RLC layer, and receiving a plurality of second MAC PDUs from the source UE directly, wherein the second MAC PDUs are composed of a plurality of first RLC PDUs and a plurality of first RLC PDU segments;

demultiplex the first MAC PDUs to retrieve the RRLC PDUs based on a header field of each first MAC PDU, and demultiplex the second MAC PDUs to retrieve the first RLC PDUs and the first RLC PDU segments based on a header field of each second MAC PDU;

reorder the RRLC PDUs and perform a duplicate detection of the RRLC PDUs according to transmission sequence numbers (TSNs), wherein each TSN is included in a header field of each RRLC PDU;

reassemble the RRLC PDUs into a plurality of second RLC PDUs and a plurality of second RLC PDU segments using information included in the header field of each RRLC PDU;

reorder the first RLC PDUs, the first RLC PDU segments, the second RLC PDUs, and the second RLC PDU segments, and perform a duplicate detection of the first RLC PDUs, the first RLC PDU segments, the second RLC PDUs, and the second RLC PDU segments according to the TSNs, wherein each TSN is included in a header field of each RLC PDU and each RLC PDU segment; and

reassemble the first RLC PDUs, the first RLC PDU segments, the second RLC PDUs, and the second RLC PDU segments into a plurality of RLC service data units (SDUs) using the information included in the header field of each RLC PDU and each RLC PDU segment.

3. A method for receiving a plurality of data packets in a wireless network, used in a communication device, comprising:

receiving one or more medium access control (MAC) protocol data units (PDUs) a) from a source user equipment (UE) of the wireless network through a relay UE and a base station, and b) directly from the source UE, wherein the MAC PDUs are composed of a plurality of radio link control (RLC) PDUs and a plurality of RLC PDU segments;

demultiplexing the MAC PDUs to retrieve the RLC PDUs and the RLC PDU segments based on a header field of each MAC PDU;

reordering the RLC PDUs and the RLC PDU segments and performing a duplicate detection of the RLC PDUs and the RLC PDU segments according to transmission sequence numbers (TSNs), wherein each TSN is included in a header field of each RLC PDU and each RLC PDU segment; and

reassembling the RLC PDUs and the RLC PDU segments into a plurality of RLC service data units (SDUs) using information included in the header field of each RLC PDU and each RLC PDU segment.

4. A method for receiving a plurality of data packets in a wireless network, used in a communication device, comprising:

receiving a plurality of first medium access control (MAC) protocol data units (PDUs) from a source user equipment (UE) of the wireless network through a relay UE and a base station, wherein the first MAC PDUs are composed of a plurality of RRLC (Relay RLC) PDUs which are protocol data units of a protocol layer between the MAC layer and the RLC layer, and receiving a plurality of second MAC PDUs from the source UE directly, wherein the second MAC PDUs are composed of a plurality of first RLC PDUs and a plurality of first RLC PDU segments;

demultiplexing the first MAC PDUs to retrieve the RRLC PDUs based on a header field of each first MAC PDU, and demultiplexing the second MAC PDUs to retrieve the first RLC PDUs and the first RLC PDU segments based on a header field of each second MAC PDU;

reordering the RRLC PDUs and performs a duplicate detection of the RRLC PDUs according to transmission sequence numbers (TSNs), wherein each TSN is included in a header field of each RRLC PDU;

reassembling the RRLC PDUs into a plurality of second RLC PDUs and a plurality of second RLC PDU segments using information included in the header field of each RRLC PDU;

reordering the first RLC PDUs, the first RLC PDU segments, the second RLC PDUs, and the second RLC PDU segments, and performing a duplicate detection of the first RLC PDUs, the first RLC PDU segments, the second RLC PDUs, and the second RLC PDU segments according to the TSNs, wherein each TSN is included in a header field of each RLC PDU and each RLC PDU segment; and

reassembling the first RLC PDUs, the first RLC PDU segments, the second RLC PDUs, and the second RLC PDU segments into a plurality of RLC service data units (SDUs) using the information included in the header field of each RLC PDU and each RLC PDU segment.