Preventing / mitigating packet loss in IAB systems
A method is performed by a wireless device for transmitting PDCP packets over a multi-hop path to a receiver, in accordance with particular embodiments. The method begins with receiving PDCP signalling indicating that at least one transmitted PDCP packet has not been received. For example, the PDCP signalling may comprise a PDCP status PDU, or may comprise PDCP data recovery or PDCP re-establishment RRC signalling. In response to receiving the PDCP signalling indicating that at least one transmitted PDCP packet has not been received, the wireless device retransmits the at least one transmitted PDCP packet that has not been received, even if said transmitted PDCP packet has been acknowledged by a lower protocol layer. A method is also performed by a network node in accordance with particular embodiments.
1. A method performed by a wireless device for transmitting Packet Data Convergence Protocol, PDCP, packets over a multi-hop path to a receiver, the method comprising:
in response to receiving a PDCP status Protocol Data Unit, PDU, and PDCP re-establishment Radio Resource Control, RRC, signaling indicating that at least one transmitted PDCP packet has not been received, retransmitting the at least one transmitted PDCP packet that has not been received, even if the transmitted PDCP packet has been acknowledged by a lower protocol layer;
discarding the transmitted PDCP packet in response to receiving a PDCP status PDU confirming that the packet has been received at the receiver and in response to expiry of a first PDCP Service Data Unit, SDU, discard timer; and
based on the wireless device connecting to a network via an Integrated Access and Backhaul, IAB, node, receiving a configuration for a second PDCP SDU discard timer that is longer than the first PDCP SDU discard timer.
2. A method performed by a wireless device for transmitting Packet Data Convergence Protocol, PDCP, packets over a multi-hop path to a receiver, the method comprising:
in response to receiving PDCP data recovery and PDCP re-establishment Radio Resource Control, RRC, signaling indicating that at least one transmitted PDCP packet has not been received, retransmitting the at least one transmitted PDCP packet that has not been received, even if the transmitted PDCP packet has been acknowledged by a lower protocol layer;
discarding the transmitted PDCP packet in response to receiving a PDCP status Protocol Data Unit, PDU, confirming that the packet has been received at the receiver and in response to expiry of a first PDCP Service Data Unit, SDU, discard timer;
based on the wireless device connecting to a network via an Integrated Access and Backhaul, IAB, node, receiving a configuration for a second PDCP SDU discard timer that is longer than the first PDCP SDU discard timer.