TCP ACK Packet Handling via PDCP Reorder Timer Bypass
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Solution Overview
Problem
In wireless communication networks, the PDCP layer's reordering mechanism for TCP ACK packets leads to delayed ACK reception at the server, increased round-trip time (RTT) calculations, and slower error recovery mechanisms, ultimately reducing overall TCP throughput.
Innovation Solution
A method for managing TCP ACK packet processing at the PDCP receiver device, where TCP ACK packets are identified based on PDCP sequence numbers and header analysis, and transferred to the upper layer without waiting for the expiry of the PDCP reorder timer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PDCP layer waits for the reorder timer to expire before delivering packets to the upper layer, then packet reordering and in-order delivery are ensured, but TCP ACK packets are delayed, increasing RTT calculations and reducing TCP throughput
Solution Approach 1:
The patent segments the packet delivery process by identifying TCP ACK packets separately from regular data packets. TCP ACK packets are extracted and delivered to the upper layer immediately without waiting for the reorder timer, while other packets continue to follow the standard reordering process. This segmentation resolves the contradiction by allowing critical ACK packets to bypass the delay mechanism that ensures general packet order.
Solution Approach 2:
The patent performs preliminary identification of TCP ACK packets at the PDCP layer before the reorder timer expires. By detecting and flagging these packets in advance based on their characteristics (ACK-only packets with specific header patterns), the system prepares them for immediate delivery, thus preventing the delay that would otherwise occur while maintaining the reorder timer for other packets.
2Reliability
If the PDCP layer buffers all packets in the reorder window, then missing packets can be recovered, but TCP ACK packets are held indefinitely, causing delayed error recovery mechanisms
Solution Approach 1:
The patent segments the buffer management by creating a special handling path for TCP ACK packets within the reorder window. These packets are identified and extracted from the general buffer, allowing them to be delivered immediately even when the reorder timer is running. This segmentation enables time-sensitive ACK packets to bypass the recovery waiting mechanism while other packets remain buffered for potential recovery.
Solution Approach 2:
The patent introduces an intermediary mechanism at the PDCP layer that acts as a filter between the reorder buffer and the upper layer. This intermediary identifies TCP ACK packets and redirects them for immediate delivery, mediating between the conflict of maintaining buffer integrity for recovery and enabling timely ACK delivery for error recovery mechanisms.
3Productivity
If the PDCP layer delivers packets immediately without waiting for the reorder timer, then TCP throughput is improved, but packet reordering and in-order delivery are compromised
Solution Approach 1:
The patent applies local quality by treating different packet types differently within the same PDCP layer. TCP ACK packets receive special treatment with immediate delivery to optimize throughput, while regular data packets continue to follow the standard reordering process to maintain delivery order. This localized differentiation resolves the contradiction by applying quality optimization only where necessary without compromising overall system reliability.
Data Source
AI summary
A method for managing transmission control protocol acknowledgement (TCP ACK) packet processing by a receiver device, including: receiving a plurality of data packets from a transmitter device at a packet data convergence protocol (PDCP) layer of the receiver device, each of the plurality of data packets including a PDCP header; determining whether a reorder timer of the PDCP layer is running or started based on PDCP sequence numbers of the received plurality of data packets included in the PDCP header; identifying, based on a determination that the reorder timer of the PDCP layer is running or started, one or more TCP ACK packets among the received plurality of data packets; and transferring, one or more identified TCP ACK packets to an upper layer without waiting for an expiry of the reorder timer of the PDCP layer.