PDCP Reordering Logic for 5G Packet Delivery Latency
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Solution Overview
Problem
The internal timing latency caused by Packet Data Convergence Protocol (PDCP) reordering in 5G NR communications systems leads to undesired service quality and user experience, as the upper layer logic has to wait for the expiry of the timer t-Reordering, resulting in unnecessary delays.
Innovation Solution
A communications apparatus with a processor configured to start a timer upon receiving a packet with a different count value and deliver subsequent packets with different count values to the upper protocol layer before the timer expires, allowing for efficient packet delivery without waiting for the timer to expire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If PDCP reordering with timer t-Reordering is configured to guarantee packet order, then packet delivery order is improved, but timing latency increases
Solution Approach 1:
The patent applies partial action by selectively delivering packets that arrive out of order without waiting for the reordering timer to expire. Instead of applying reordering uniformly to all packets, the system identifies specific packets that can be delivered immediately (those with count values indicating they are ready for delivery) and delivers them partially, while still maintaining order for packets that require waiting. This reduces unnecessary waiting time while preserving packet order where required.
2Reliability
If the timer t-Reordering is started to ensure proper packet sequencing, then packet order reliability is improved, but service quality deteriorates due to waiting delays
Solution Approach 1:
The patent applies preliminary action by checking packet count values and determining deliverability before the reordering timer expires. The system performs preliminary assessment of each received packet to determine if it can be immediately delivered to the upper layer, rather than waiting passively for timer expiration. This proactive approach allows packets to be delivered as soon as they are ready, improving service quality while maintaining reliability for packets that truly require reordering.
3Stability of the object's composition
If packets are delivered only after timer t-Reordering expires, then packet ordering is maintained, but internal latency increases unnecessarily
Solution Approach 1:
The patent applies dynamics by making the packet delivery process adaptive rather than static. Instead of rigidly waiting for timer expiration for all packets, the system dynamically adjusts delivery timing based on individual packet characteristics (count values). Packets are delivered immediately when their count values indicate they are ready, while only packets requiring reordering wait for the timer. This dynamic approach reduces internal latency while maintaining packet ordering where necessary.
Data Source
AI summary
A communications apparatus includes a receiver and a processor. The receiver is configured to receive wireless signals. The wireless signals include a plurality of packets. The processor is coupled to the receiver and includes a first logic configured to perform operations of a first protocol layer and a second logic configured to perform operations of a second protocol layer higher than the first protocol layer. The operations of the first protocol layer includes: starting a timer in response to receiving a first packet with a first count value that is different from a deliver count value; and delivering a second packet with a second count value that is different from the deliver count value to the second logic before the timer expires.