Proactive PUSCH Grants Prevent Downlink Throttling

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Solution Overview

Problem

In LTE wireless systems, high Tsr values assigned to UEs can increase TCP ACK latency, leading to downlink throughput throttling due to reduced access to uplink resources for UEs without uplink traffic, which affects PDSCH throughput.

Innovation Solution

The base station proactively grants uplink resources to UEs with high downlink throughput, reducing TCP ACK latency by determining the time since the last SR opportunity and making proactive grants when necessary to ensure timely access to the uplink channel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If large Tsr values are assigned to UEs to reduce PUCCH RB usage, then the number of PUCCH RBs is reduced, but TCP ACK latency increases and downlink throughput is throttled

Engineering Contradiction:

ImprovePUCCH RB usageVSAvoidTCP ACK latency

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The base station performs preliminary actions by proactively granting uplink resources before the UE needs to transmit TCP ACKs. The base station monitors downlink throughput and anticipates the need for uplink resources, sending proactive grants to ensure timely ACK transmission without waiting for the UE to actually need them, thus reducing latency while maintaining efficient PUCCH usage.

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If large Tsr values are assigned to UEs, then access to uplink resources is reduced, but downlink throughput is throttled due to increased TCP ACK latency

Engineering Contradiction:

ImproveUplink resource accessVSAvoiddownlink throughput

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The base station implements feedback mechanisms by monitoring downlink throughput performance and using this information to trigger proactive uplink grants. When the base station detects high downlink throughput, it sends feedback in the form of proactive grants to ensure the UE can transmit ACKs timely, creating a closed-loop system that maintains throughput while managing uplink resources efficiently.

Inventive Principle:

Principle #23Feedback

3Device complexity

If UE waits for next SR opportunity to transmit TCP ACKs, then uplink resource allocation is simplified, but TCP ACK latency increases causing throughput throttling

Engineering Contradiction:

ImproveUplink resource allocationVSAvoidTCP ACK latency

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The base station takes preliminary action by proactively granting uplink resources before the UE reaches its next SR opportunity. This allows the UE to transmit TCP ACKs earlier than would normally be possible, reducing latency without requiring complex changes to the UE's resource allocation logic. The base station initiates the grant process in advance based on monitored downlink throughput conditions.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11116000B2Proactive PUSCH grants to prevent rate throttling

Publication Date: 2021.09.07 OUTDOOR WIRELESS NETWORKS LLC

AI summary

One embodiment is directed to transmitting user data to a UE from a base station on a shared downlink channel and determining if a throughput for the user data transmitted to the UE on the shared downlink channel is greater than a threshold amount. If the throughput for the user data transmitted to the UE on the shared downlink channel is greater than the threshold amount, the base station provides the UE with a minimum amount of access to a shared uplink channel by making proactive grants of uplink resources when such UE is more in need of a proactive grant than other UEs. Other embodiments are disclosed.