PDCP and SDAP Concatenation for Lower L2 Processing Overhead

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Solution Overview

Problem

Existing 3GPP NR wireless networks face inefficiencies in handling multiple small packets due to high L2 header processing overhead and CPU load increases, particularly at the MAC sublayer, which is exacerbated by transmission control protocol acknowledgments and extended reality applications with many small packets.

Innovation Solution

Implement PDCP and SDAP concatenation at higher sublayers, combining multiple small packets into a single PDCP PDU to reduce the number of security and header processing operations, thereby simplifying L2 processing and reducing overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple small packets are transmitted individually at the MAC sublayer, then transmission control protocol acknowledgments and extended reality applications can be handled, but L2 header processing overhead increases and CPU load increases

Engineering Contradiction:

Improvepacket transmission capabilityVSAvoidL2 header processing overhead

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple Service Data Units (SDUs) from different logical channels into a single MAC PDU at the MAC sublayer. This merging approach reduces the number of L2 headers that need to be processed, as multiple SDUs share a common MAC header structure. The MAC layer consolidates multiple small packets into one transmission unit, thereby reducing processing overhead while maintaining the ability to handle TCP acknowledgments and XR applications efficiently

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If multiple small packets are transmitted individually, then protocol requirements are met, but CPU load increases due to repeated security and header processing operations

Engineering Contradiction:

Improveprotocol complianceVSAvoidCPU load

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent merges multiple SDUs into a single MAC PDU, allowing security processing (integrity protection and encryption) to be performed once on the combined data rather than repeatedly on each individual packet. This significantly reduces CPU load and energy consumption while maintaining protocol compliance through proper inclusion of logical channel identifiers and length indicators for each concatenated SDU

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If concatenation is implemented at the MAC sublayer, then L2 header processing efficiency is improved, but compatibility with existing 3GPP NR standards must be maintained

Engineering Contradiction:

ImproveL2 header processing efficiencyVSAvoidstandard compatibility

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements segmentation by dividing the MAC PDU into multiple MAC SDUs at the upper layers, each representing a logical channel's data. This segmentation approach allows the MAC layer to efficiently concatenate physical packets while maintaining the logical structure required by 3GPP NR standards. The inclusion of length indicators and logical channel identifiers within the MAC PDU ensures that upper layers can properly interpret and process the concatenated data according to existing standards

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12402032B2Communication devices and methods for concatenating service data units

Publication Date: 2025.08.26 APPLE INC

AI summary

The present application relates to devices and components including apparatus, systems, and methods for concatenating in the packet data convergence protocol sublayer or the service data adaptation sublayer in wireless networks.