UCMP Routing for LTE-WLAN IP Flow Aggregation

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Solution Overview

Problem

Current LTE-WLAN interworking architectures, specifically LWIP, face disadvantages in aggregating IP flows due to the use of a bearer switch, leading to inefficiencies compared to LWA architectures that provide link aggregation, resulting in challenges in balancing loads across LTE and WLAN links.

Innovation Solution

The implementation of unequal cost multipath (UCMP) routing logic that determines and normalizes routing metrics for LTE and WLAN networks, allowing for dynamic load balancing across these networks by selecting the most capable path for IP flows based on uplink/downlink throughput, signal strength, and channel utilization, thereby facilitating link aggregation without reordering PDCP sequence numbers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a bearer switch is used to route IP flows between LTE and WLAN communication links, then routing decisions can be made, but the architecture cannot aggregate IP flows over both links simultaneously, resulting in lost productivity

Engineering Contradiction:
ImproveIP flow aggregation capabilityVSAvoidrouting architecture complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the routing function by introducing separate routing metrics for uplink and downlink directions. The UCMP routing logic independently determines routing paths for each direction based on respective metrics, enabling simultaneous aggregation over LTE and WLAN links while maintaining architectural simplicity through directional separation of routing decisions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic routing metrics that continuously adapt to changing network conditions. The routing metrics are updated based on real-time measurements of throughput, signal strength, and channel utilization, allowing the system to dynamically optimize IP flow aggregation across LTE and WLAN links without requiring complex static configuration

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If routing metrics are determined separately for uplink and downlink, then accurate path selection is achieved, but the measurement and determination process becomes more complex

Engineering Contradiction:
Improverouting metric accuracyVSAvoidmetric determination complexity
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent divides the routing metric determination into separate uplink and downlink measurements. Each direction has its own dedicated metric calculation based on direction-specific network conditions, improving accuracy by capturing asymmetric channel characteristics while simplifying implementation through independent measurement processes for each transmission direction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs self-measurement of routing metrics using built-in capabilities of the communication interfaces. The UE and network elements automatically measure throughput, signal strength, and channel utilization without requiring external measurement tools, reducing measurement complexity while maintaining high precision through direct feedback from the communication channels

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3571867B1System and method to facilitate unequal cost multipath routing in a network environment
Publication Date: 2024.11.20 CISCO TECHNOLOGY INC
  • EP3571867B1 patent drawingFigure 1
  • EP3571867B1 patent drawingFigure 2A
  • EP3571867B1 patent drawingFigure 2B

AI summary

An example method is provided in one example embodiment and may include determining a first routing metric associated with a first communication network, wherein the first routing metric identifies a capability of the first communication network to handle an Internet Protocol (IP) flow for a user equipment (UE); determining a second routing metric associated with a second communication network, wherein the second routing metric identifies a capability of the second communication network to handle the IP flow for the UE and wherein the second routing metric is different from the first routing metric; and routing the IP flow for the UE using the first communication network or the second communication network based, at least in part, on the first routing metric and the second routing metric.