PDCP Compression Location in LTE MBMS

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Solution Overview

Problem

In LTE telecommunications networks, the overhead required for point-to-point (PTP) communication with multiple user equipment (UEs) is substantial, leading to inefficient spectrum usage, while point-to-multipoint (PTM) communication, although more efficient, may compromise quality due to limited UE feedback and power considerations.

Innovation Solution

Implementing a system where the Packet Data Convergence Protocol (PDCP)-based data compression function for Internet Protocol (IP) headers is executed in either the access gateway or enhanced node B (ENB) based on the known or unknown quantity of cells providing a service, optimizing data transmission by compressing IP headers when multiple cells are involved and sending uncompressed data when only one cell is involved.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If point-to-point (PTP) communication is used to provide high quality communication with each UE, then communication quality is improved, but substantial overhead is required and spectrum efficiency deteriorates

Engineering Contradiction:
Improvecommunication qualityVSAvoidspectrum efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent segments the communication approach by using PTP for individual UE high-quality communication when needed, while using PTM for group communication to improve spectrum efficiency. The PDCP layer is segmented to perform compression individually for PTP while enabling shared compression for PTM, resolving the contradiction between quality and efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects between PTP and PTM communication modes based on the number of UEs and service requirements. When few UEs are served, PTP provides high quality; when many UEs are served, PTM improves spectrum efficiency. The PDCP compression function dynamically adapts its operation based on the communication mode and number of cells.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If point-to-multipoint (PTM) communication is used to improve spectral efficiency with multiple UEs, then spectral efficiency is improved, but communication quality may worsen due to limited UE feedback and power considerations

Engineering Contradiction:
Improvespectral efficiencyVSAvoidcommunication quality
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent merges the advantages of both PTP and PTM by implementing PDCP compression at the access gateway that serves multiple cells. This centralized compression enables efficient PTM communication while maintaining quality through coordinated data processing across multiple cells, combining the spectral efficiency of PTM with the quality control capabilities of PTP.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If PDCP-based data compression is performed at the access gateway for multiple cells, then data transmission efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidcompression function location
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The access gateway is designed with universal multi-functionality to perform PDCP compression for multiple cells simultaneously. This single location handles compression tasks for all participating cells in the MBMS service area, eliminating the need for each cell to have separate compression capabilities and actually reducing overall system complexity while improving efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Device complexity

If PDCP-based data compression is performed at the ENB for a single cell, then device complexity is reduced, but data transmission efficiency deteriorates when multiple cells are involved

Engineering Contradiction:
Improvecompression function locationVSAvoiddata transmission efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The access gateway acts as an intermediary that performs centralized PDCP compression for multiple cells. This intermediary approach allows individual ENBs to remain relatively simple while still benefiting from efficient compression across multiple cells. The access gateway mediates the compression function, enabling multi-cell efficiency without increasing ENB complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2154866B1Location of packet data convergence protocol in a long-term evolution multimedia broadcast multicast service
Publication Date: 2015.07.01 BLACKBERRY LTD
  • EP2154866B1 patent drawingFigure 1~2
  • EP2154866B1 patent drawingFigure 3
  • EP2154866B1 patent drawingFigure 4

AI summary

A system for compressing an Internet Protocol (IP) header for a multimedia broadcast multicast service (MBMS) is provided. The system includes an access gateway 110 and a plurality of cells 102, each of which has an enhanced node B (ENB) 20. When the quantity of cells 102 that will provide the MBMS is known to be one, execution of a packet data convergence protocol (PDCP)-based data compression function for the IP header occurs in the ENB 20 of the one cell 102. When the quantity of cells 102 that will provide the MBMS is not known to be one, execution of the PDCP-based data compression function occurs in the access gateway 110.