Network Device Channel Reservation in Unlicensed Spectrum

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Solution Overview

Problem

Current mobile communication systems face challenges in managing the rapid increase in mobile data traffic, particularly in utilizing unlicensed spectrum resources effectively to alleviate frequency resource pressure and improve network capacity.

Innovation Solution

A signal transmission method that involves configuring a second downlink signal in a guard period for uplink and downlink switching, allowing the network device to perform second downlink transmission after the first downlink transmission, reserving the channel for terminal devices without requiring them to send signals, thus saving power and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If terminal devices send signals to reserve channels in unlicensed spectrum, then channel reservation reliability is improved, but terminal device power consumption increases

Engineering Contradiction:

Improvechannel reservation reliabilityVSAvoidterminal device power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The network device acts as an intermediary to reserve channels on behalf of terminal devices. Instead of terminals directly transmitting signals to reserve channels, the network device sends downlink signals during guard periods to achieve channel reservation, thereby reducing terminal power consumption while maintaining reservation reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent inverts the traditional channel reservation approach by having the network device perform channel reservation through downlink transmission rather than having terminal devices perform uplink transmission. This inversion allows terminals to save power while the network device leverages its existing downlink capabilities for reservation purposes

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If terminal devices perform channel sensing and send reservation signals, then channel access reliability is improved, but system throughput decreases due to additional signal transmission

Engineering Contradiction:

Improvechannel access reliabilityVSAvoidsystem throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges the channel sensing function with the existing downlink transmission function. The network device combines channel status detection with its regular downlink signal transmission during guard periods, eliminating the need for separate terminal device reservation signals and thus maintaining throughput while ensuring reliable channel access

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The network device performs self-service by using its own downlink transmission capabilities to reserve channels that would traditionally require terminal device participation. This self-service approach eliminates additional uplink reservation signals and maintains system throughput

Inventive Principle:

Principle #25Self-service

3Productivity

If network device performs second downlink transmission after first downlink transmission, then unlicensed spectrum utilization is improved, but interference to other systems increases

Engineering Contradiction:

Improveunlicensed spectrum utilizationVSAvoidinterference to other systems

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent employs periodic action by utilizing guard periods between downlink transmissions for channel reservation. This periodic use of available time slots allows the network to efficiently utilize unlicensed spectrum resources without continuous transmission, thereby reducing overall interference while maintaining high utilization

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The network device performs preliminary channel reservation during guard periods before actual data transmission. This preliminary action ensures channel availability is secured in advance, allowing efficient use of unlicensed spectrum while minimizing interference by avoiding unnecessary continuous transmissions

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11330442B2Signal transmission method and apparatus

Publication Date: 2022.05.10 HUAWEI TECH CO LTD

AI summary

A signal transmission method and apparatus, the method including obtaining, by a network device, an end moment of first downlink transmission, where the first downlink transmission occupies at least one of one or more downlink subframes, a downlink transmission part of a self-contained subframe, or a combination of one or more downlink subframes and a downlink transmission part of a self-contained subframe, and performing, by the network device, second downlink transmission in an unlicensed frequency band after a first guard period from the end moment of the first downlink transmission, where at least one terminal device senses a channel in the first guard period, and the second downlink transmission is used to reserve the channel for the at least one terminal device.