Wireless Device NOMA in Unlicensed Bands via LBT Segmentation

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Solution Overview

Problem

Current technologies cannot implement non-orthogonal multiple access (NOMA) in the uplink transmission of unlicensed frequency bands due to the Listen Before Talk (LBT) mechanism, limiting spectral efficiency and user fairness.

Innovation Solution

A wireless communication device and method that detect broadcast information on subchannels in unlicensed frequency bands, broadcast time information to determine channel occupation, and select resources for uplink transmission using MA signatures, enabling NOMA by managing channel access and updating available resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Listen Before Talk (LBT) mechanism is used in unlicensed frequency band, then channel access conflict is avoided, but non-orthogonal multiple access (NOMA) cannot be implemented

Engineering Contradiction:

Improvechannel access reliabilityVSAvoidNOMA implementation capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the channel access process into two distinct phases: LBT phase for channel acquisition and NOMA phase for multi-user transmission. During LBT phase, devices perform traditional LBT to acquire channel access. Once channel is acquired, the patent enables NOMA by allowing multiple devices to transmit simultaneously using different MA signatures during the same time-frequency resource, thus segmenting the contradiction between reliable channel access and NOMA capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by performing LBT channel access before enabling NOMA transmission. Devices first compete for channel access using LBT mechanism, and the winning device(s) then establish the channel occupation. Subsequently, multiple user equipments can perform uplink NOMA transmission during the occupied channel time, thus preparing the channel in advance before implementing NOMA.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If one transmission resource is allocated to one user equipment using orthogonal multiple access (OMA), then interference is avoided, but spectral efficiency is reduced

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidspectral efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple user equipment transmissions into the same time-frequency resource by introducing MA signatures. Instead of allocating separate orthogonal resources to each device, the patent combines multiple uplink signals from different user equipments on the same resource block, with each device distinguished by its unique MA signature. This merging approach enables spectral efficiency improvement while maintaining transmission reliability through signature-based separation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the transmission parameter by introducing MA signatures as an additional dimension for signal differentiation. Rather than relying solely on orthogonal time-frequency resources, the patent modifies the transmission scheme to include code-domain separation through MA signatures, allowing multiple devices to share the same resource while maintaining distinguishability and reliability.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If multiple user equipments use the same transmission resource in NOMA, then spectral efficiency is improved, but interference management complexity increases

Engineering Contradiction:

Improvespectral efficiencyVSAvoidinterference management complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces MA signatures as an intermediary mechanism to manage interference in NOMA systems. The MA signatures act as a mediator that separates multiple user signals in the code domain, allowing the receiver to distinguish and decode individual user transmissions even when they share the same time-frequency resource. This intermediary approach manages interference complexity by providing a structured separation mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If Listen Before Talk (LBT) mechanism is used, then fair channel access is ensured, but multiple access signatures cannot be used for user differentiation

Engineering Contradiction:

Improvechannel access fairnessVSAvoiduser differentiation capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the communication process into channel access phase and data transmission phase. During the channel access phase, LBT mechanism ensures fair channel acquisition. During the data transmission phase, multiple user equipments that have acquired channel access can use different MA signatures for user differentiation. This segmentation allows both LBT fairness and MA signature versatility to coexist in different phases of the communication process.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11277818B2Wireless communication method and wireless communication device

Publication Date: 2022.03.15 SONY GROUP CORP

AI summary

Disclosed are a wireless communication method and a wireless communication device. The wireless communication device comprises a processing circuit, wherein the processing circuit is configured to: detect broadcast information on a specific subchannel in an unlicensed frequency band; and broadcast time information on the specific subchannel when the broadcast information cannot be successfully detected, wherein the time the occupation of the specific subchannel by the wireless communication device ends can be determined according to the time information.