Pre-coded RTS/CTS for Synchronous NR-SS Interference

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Solution Overview

Problem

Current wireless communication systems face interference challenges in shared spectrum networks, leading to inefficiencies and increased latency due to the need for medium-sensing procedures among multiple network operating entities, which can result in communication inefficiencies, especially in 5G networks with diverse deployments and services.

Innovation Solution

The implementation of pre-coded request-to-send (RTS)/clear-to-send (CTS) signals using directional contention operations and precoding of tentative transmission parameters in the contention operations, allowing for priority access and opportunistic use of shared communication channels, thereby reducing the need for training phases and conserving resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If medium-sensing procedures are implemented among multiple network operating entities in shared spectrum networks, then interference management is achieved, but communication efficiency deteriorates and latency increases

Engineering Contradiction:
Improveinterference managementVSAvoidcommunication efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by implementing pre-coded RTS/CTS signals that carry tentative transmission parameters before actual data transmission. The precoding is performed in advance using available channel state information, allowing the system to prepare interference mitigation strategies beforehand rather than reacting to interference in real-time through medium-sensing procedures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes parameters by using precoded tentative transmission parameters (such as precoding matrices, rank indicators, and beamforming vectors) in the RTS/CTS handshake. These parameters are optimized based on channel conditions and used to pre-shape the transmission signals, thereby proactively managing interference without requiring continuous medium-sensing during data transmission.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If medium-sensing procedures are implemented among multiple network operating entities in shared spectrum networks, then interference management is achieved, but signaling overhead increases

Engineering Contradiction:
Improveinterference managementVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent embeds tentative transmission parameters directly in the pre-coded RTS/CTS signals, performing the coding operation in advance. This preliminary encoding consolidates multiple pieces of transmission information into the contention reservation signals, reducing the need for separate training phases and subsequent signaling exchanges that would otherwise increase overhead.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the contention resolution function with transmission parameter indication by incorporating tentative transmission parameters into the RTS/CTS signals. This combination allows the system to simultaneously perform medium access control and transmission parameter negotiation in a single signaling exchange, thereby reducing overall signaling overhead while maintaining interference management capabilities.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If training phases are required for determining transmission parameters, then transmission reliability is improved, but resource consumption increases

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidresource consumption
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent performs precoding in advance using available channel state information before actual data transmission. By determining and applying tentative transmission parameters in the pre-coded RTS/CTS signals, the system eliminates or reduces the need for separate training phases, thereby maintaining transmission reliability while conserving time and frequency resources.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses tentative transmission parameters derived from previous channel measurements and estimates as copies of optimal parameters for upcoming transmissions. These pre-determined parameters are embedded in the RTS/CTS signals and used directly for data transmission without requiring additional training, effectively copying proven parameter sets to maintain reliability while reducing resource consumption.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3679669B1Pre-coded RTS/CTS for synchronous NR-ss
Publication Date: 2022.03.23 QUALCOMM INC
  • EP3679669B1 patent drawingFigure 1
  • EP3679669B1 patent drawingFigure 2
  • EP3679669B1 patent drawingFigure 3

AI summary

Precoded contention reservation signals for synchronous new radio (NR) shared spectrum (NR-SS) networks are disclosed. A transmitter that uses precoded contention reservation signals may be configured either to skip or use the training phase for determining rank parameters. The transmitter participates in contention resolution with its receiver by transmitting the precoded contention reservation signals precoded with tentative rank parameters. After contention interval, receiver sends feedback to the transmitter identifying proposed rank parameters based on the strongest precoded contention signals of any neighboring nodes that also won access to the channel. When configured to skip the training phase, the transmitter sets the rank parameters according to the proposed rank parameters. Otherwise, the transmitter participates in the training phase with other winning nodes transmitting signals identifying proposed rank parameters. The receiver then feeds back refined rank parameters to the transmitter based on each of the proposed rank parameters of the training phase.