Congestion Indication Backoff for Wireless Scheduling Request Load Control

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Solution Overview

Problem

Modern wireless communication systems face challenges in accurately scheduling uplink transmissions due to limited information granularity and frequency of Buffer Status Reports (BSR) and Scheduling Requests (SR), leading to increased response delays and channel overload, especially with higher bit-rates and new use cases requiring short transmissions with extreme delay requirements.

Innovation Solution

A method is introduced to transmit a congestion indication to wireless communication devices, triggering synchronized backoff procedures to defer scheduling requests until the backoff procedure is completed, thereby controlling load and reducing average response time between scheduling requests and grants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the frequency of Scheduling Request (SR) transmissions is increased to improve scheduling accuracy, then the response delay decreases, but the channel overload increases

Engineering Contradiction:

Improveresponse delayVSAvoidchannel load

Core Design Contradiction:

Loss of timeVSQuantity of substance

Solution Approach 1:

The network node transmits a congestion indication to wireless communication devices before the channel becomes overloaded. This preliminary warning triggers devices to perform backoff procedures and defer SR transmissions, preventing channel overload before it occurs. The congestion indication acts as a preemptive measure to balance response delay and channel load.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system implements a feedback mechanism where the network node monitors channel congestion levels and sends congestion indications back to wireless communication devices. This feedback loop allows devices to adjust their SR transmission behavior dynamically based on current channel conditions, reducing SR transmissions when congestion is detected while maintaining acceptable response delays.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If the granularity of Buffer Status Reports (BSR) is increased to improve scheduling information accuracy, then the scheduling precision improves, but the processing complexity increases

Engineering Contradiction:

Improvescheduling information accuracyVSAvoidprocessing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of continuously transmitting detailed BSR reports with high granularity, the system uses partial action by only transmitting BSR reports when necessary (triggered by specific events). The congestion indication mechanism complements this by providing coarse-grained load control, allowing the system to achieve adequate scheduling precision without the full processing complexity of continuous high-granularity BSR reporting.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If the frequency of SR transmissions is increased to reduce response delay, then the scheduling responsiveness improves, but the channel overload and processing limitations are exceeded

Engineering Contradiction:

Improvescheduling responsivenessVSAvoidchannel capacity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system dynamically adjusts SR transmission behavior based on real-time channel conditions. When congestion indications are not present, devices can transmit SRs with higher frequency to maintain responsiveness. When congestion indications are received, devices dynamically reduce SR transmission frequency through backoff procedures. This dynamic adaptation allows the system to maintain scheduling responsiveness while preventing channel overload.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11115994B2Triggering/initiating backoff procedure(s) based on congestion indication(s) to defer scheduling request transmission

Publication Date: 2021.09.07 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

There is provided a method and corresponding device for transmitting a congestion indication to a group of wireless communication devices for synchronized triggering of backoff procedures in the wireless communication devices. A purpose of the synchronized triggering of the backoff procedures may be to enable deferring, in each of the wireless communication devices, transmission of scheduling request(s) until one or more backoff procedures in the considered wireless device is completed. In this way, the proposed technology provides efficient load control related to scheduling requests and/or enables a reduction of the average response time between scheduling request and grant.