Methods and apparatus for data volume counting

A method performed by a relay user equipment (UE) supporting device-to-device (D2D) communications, wherein the relay UE is capable of providing a connection to a communication network for a remote UE and the relay UE is configured with a primary Radio Link Control (RLC) entity and a split secondary RLC entity, the method comprising:

• monitoring a data traffic volume at the relay UE;
• and
• determining a first size value and a second size value, the first size value indicating a size of a first portion of the data traffic volume, and the second size value indicating a size of a second portion of the data traffic volume, wherein
• the first portion of the data traffic volume relates to the relay UE, comprising Packet Data Convergence Protocol (PDCP) Protocol Data Units (PDUs) of the relay UE, and/or Radio Link Control (RLC) data of the relay UE, and
• the second portion of the data traffic volume relates to the remote UE that is connected to the relay UE, comprising PDCP PDU and/or RLC data of the remote UE;
• determining, based at least in part on the first size value, whether to send a PDCP PDU of the relay UE to the split secondary RLC entity;
• and
• determining, based at least in part on the second size value, whether to send a PDCP PDU of the remote UE to the split secondary RLC entity, wherein
• determining whether to send the PDCP PDU of the relay UE to the split secondary RLC entity based at least in part on the first size value comprises:
• comparing the first size value with a first threshold, or
• comparing a sum of the first and second size values with the first threshold.