Physical Layer Radio Condition Feedback for LTE Data Rate Adaptation

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Solution Overview

Problem

Current LTE technologies lack a clear mechanism to quickly adjust the behavior of Variable Bit Rate (VBR) applications based on deteriorating or improving radio conditions, leading to delayed reactions to RAN issues and impacting user experience.

Innovation Solution

Implementing a system where the physical layer of a user device directly conveys radio conditions to the application layer, enabling quicker data rate adjustments based on metrics like SINR, BLER, and queue congestion, without requiring additional traffic or latency-inducing tests.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If application layer messaging is used to determine bandwidth and latency, then data rate adjustments can be made, but additional latency is introduced and reaction to radio conditions is delayed

Engineering Contradiction:

Improvedata rate adjustment capabilityVSAvoidreaction time to radio conditions

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent introduces the physical layer as an intermediary that directly conveys radio condition information to the application layer, bypassing the latency-inducing application layer messaging loop. This intermediary mechanism enables real-time radio condition feedback without the time loss associated with traditional end-to-end bandwidth measurement protocols.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary action by having the physical layer continuously monitor and prepare radio condition information in advance, making it immediately available to the application layer when needed, rather than waiting for application layer requests or periodic measurements to trigger data rate adjustments.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If traditional application layer feedback mechanisms are used, then data rate can be adjusted based on packet loss and latency, but the reaction to deteriorating radio conditions is delayed

Engineering Contradiction:

Improvedata rate adaptation reliabilityVSAvoidtime to react to radio conditions

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements a direct feedback mechanism where the physical layer continuously monitors radio conditions (SINR, BLER, queue status) and provides real-time feedback to the application layer. This eliminates the delayed feedback loop inherent in traditional application layer messaging, enabling immediate data rate adjustments in response to radio condition changes.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If VBR techniques are implemented without direct physical layer feedback, then applications can request data rate adjustments, but the system cannot quickly respond to deteriorating radio conditions

Engineering Contradiction:

ImproveVBR application data rate controlVSAvoidresponse speed to radio condition changes

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The physical layer performs preliminary monitoring and preparation of radio condition information continuously, so that when the application layer needs to adjust data rates, the necessary information is already available immediately, enabling fast response without waiting for measurements or messages to traverse the network.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10027448B2Methods of adapting codec data rate based on radio condition to improve LTE service coverage and capacity

Publication Date: 2018.07.17 VERIZON PATENT & LICENSING INC

AI summary

Variable bitrate (“VBR”)-based applications may use physical layer metrics, associated with a radio access network (“RAN”), in order to select a data rate and/or codec at which to send and/or receive data. Such VBR-based applications may include voice call application, video streaming applications, or the like. An application programming interface (“API”) between the physical layer and the application layer of a user device may facilitate the analysis of the physical layer metrics of the RAN. The RAN may also, or alternatively, provide physical layer metrics to the user device (e.g., via control signaling). The RAN may enforce constraints on maximum or minimum data rates, and/or may specify codecs that should be used.