Parallel LBT Procedures for DRS Transmission in LAA Networks

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current License-Assisted Access (LAA) channel evaluation methods in wireless communication networks face challenges in successfully transmitting Discovery Reference Signals (DRS) due to increased risk of LBT procedure failure when attempting to include additional data, leading to potential interference from other transmissions and inefficient spectrum resource utilization.

Innovation Solution

Implementing parallel Listen Before Talk (LBT) procedures for data and DRS transmissions, where a normal LBT for data is initiated near the subframe boundary, and a shorter LBT for DRS is started concurrently, allowing for successful DRS transmission even if data transmission fails, thereby optimizing spectrum use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a normal LBT procedure is used for DRS transmission to include additional data, then the quantity of transmitted data increases, but the risk of LBT failure increases

Engineering Contradiction:

Improvequantity of transmitted dataVSAvoidLBT success rate

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent segments the LBT procedure into two separate parallel processes: a normal LBT for data transmission and a shorter LBT for DRS transmission. This segmentation allows the system to attempt data transmission with full LBT while having a backup shorter LBT ready for DRS-only transmission, thereby reducing the overall risk of transmission failure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent initiates the normal LBT procedure in advance before the DRS transmission opportunity. By starting the normal LBT early, the system prepares for potential data transmission while still having time to fall back to the shorter LBT procedure if needed, ensuring that DRS transmission can still occur even if the normal LBT fails.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a shorter LBT procedure is used for DRS transmission, then the LBT success rate increases, but the opportunity to send additional data is lost

Engineering Contradiction:

ImproveLBT success rateVSAvoidquantity of transmitted data

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent implements a dynamic LBT strategy where the system adaptively selects between normal and shorter LBT procedures based on real-time conditions. The normal LBT is attempted first to maximize data transmission opportunities, but the system dynamically switches to the shorter LBT if the normal LBT fails or time is running out, thus optimizing both data quantity and reliability based on actual channel conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent makes the LBT system multi-functional by designing it to perform both normal data transmission and DRS-only transmission through two different LBT procedures. The system can universally handle both transmission types by selecting the appropriate LBT procedure, making the transmission mechanism adaptable to different transmission needs and conditions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Quantity of substance

If LBT procedure time is extended to include more data, then the quantity of transmitted data increases, but the risk of channel interference increases

Engineering Contradiction:

Improvequantity of transmitted dataVSAvoidchannel interference risk

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent ensures continuous useful action by running both normal and shorter LBT procedures in parallel. This continuity guarantees that if one LBT procedure fails to secure the channel, the other can immediately take over, maintaining the transmission opportunity without interruption and reducing the window of vulnerability to channel interference.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

By initiating the normal LBT procedure in advance and having the shorter LBT procedure ready as a backup, the system performs preliminary actions to secure transmission rights before the actual DRS transmission window. This preliminary preparation reduces the risk of interference by ensuring that transmission can begin as soon as possible regardless of which LBT procedure succeeds.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11350456B2Network node and method for evaluating channel of license-assisted access cell in wireless communication network

Publication Date: 2022.05.31 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A network node (110) and method therein for evaluating a channel in a License Assisted Access, LAA, cell in a wireless communication network (100) are disclosed. The network node starts a Listen Before Talk, LBT, procedure for data transmission when a Discovery Reference Signal, DRS, is to be transmitted; and start an LBT procedure for DRS transmission in parallel with the LBT procedure for data transmission when a time of the LBT procedure for data transmission reaches a predefined value or the LBT procedure for data transmission fails.