Indication Frame Reduces WLAN Transmission Overhead

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Solution Overview

Problem

In wireless local area networks (WLANs), especially with OFDMA technology, the existing RTS/CTS mechanism incurs high overheads in reporting available bandwidth, leading to inefficient data transmission due to hidden node interference and unnecessary channel assessments.

Innovation Solution

The method involves generating an indication frame that carries available-channel or idle bandwidth information, allowing multiple transmit end nodes to simultaneously send this information to a receive end node, reducing the need for individual channel reports and improving channel assessment efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the RTS/CTS mechanism is used to prevent hidden node interference, then channel access reliability is improved, but transmission overhead increases significantly

Engineering Contradiction:
Improvechannel access reliabilityVSAvoidtransmission overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the essential function of the RTS/CTS mechanism (preventing hidden node interference) and implements it selectively only when needed. Instead of always performing full RTS/CTS handshakes, the system extracts and applies only the necessary channel assessment and NAV setting functions when hidden nodes are detected or suspected, thereby reducing unnecessary transmission overhead while maintaining reliability where required

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by implementing a simplified version of the RTS/CTS mechanism. Rather than requiring complete RTS and CTS frame exchanges for all transmissions, the system performs partial channel assessment and selective NAV setting based on actual hidden node conditions. This partial implementation reduces overhead significantly while maintaining sufficient reliability for preventing hidden node interference

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If individual channel reports are required from multiple transmit end nodes, then channel information accuracy is improved, but system complexity and overhead increase

Engineering Contradiction:
Improvechannel information accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges channel information from multiple transmit end nodes into a unified channel assessment result. Instead of requiring separate individual channel reports that would increase system complexity, the receiving node combines channel status information from multiple sources and performs a single unified channel assessment, thereby maintaining measurement precision while reducing system complexity and overhead

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The receiving node performs a universal channel assessment function that serves multiple transmit end nodes simultaneously. This multi-functional approach allows a single channel assessment result to be used by multiple nodes, eliminating the need for separate individual reports and reducing overall system complexity while maintaining accurate channel information for all participants

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If bandwidth information is exchanged using existing RTS/CTS mechanism, then hidden node robustness is improved, but transmission efficiency decreases due to excessive overhead

Engineering Contradiction:
Improvehidden node robustnessVSAvoidtransmission efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts the essential bandwidth indication function from the RTS/CTS mechanism and applies it selectively. Instead of requiring full bandwidth information exchange through complete RTS/CTS handshakes for all transmissions, the system extracts and applies bandwidth indication only when hidden node conditions are present, thereby maintaining robustness where needed while improving overall transmission efficiency by eliminating unnecessary overhead

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements partial bandwidth information exchange by providing bandwidth indications only when necessary for hidden node protection. Rather than requiring complete bandwidth information exchange in all RTS/CTS interactions, the system performs partial information exchange based on actual hidden node conditions, thereby improving transmission efficiency while maintaining sufficient robustness for preventing hidden node interference

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3657853B1Method, apparatus, and system for transmitting data that carries indication information
Publication Date: 2023.10.04 HUAWEI TECH CO LTD
  • EP3657853B1 patent drawingFigure 1~2
  • EP3657853B1 patent drawingFigure 3
  • EP3657853B1 patent drawingFigure 4~6

AI summary

The present invention provides a method and a system for transmitting data that carries indication information, and an apparatus. The method includes: generating, by a transmit end node, an indication frame; and sending, by the transmit end node, the indication frame to a receive end node, where the indication frame includes available-channel indication information or idle bandwidth information. The receive end node can directly receive indication frames sent by multiple transmit end nodes, and does not need to receive, one piece by one piece, indication information sent by the multiple transmit end nodes. This greatly reduces transmission overheads.