PPDU Bandwidth Determination with Scrambling-Sequence Error Recovery

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Solution Overview

Problem

Existing bandwidth negotiation methods in wireless local area networks are inefficient and lead to unnecessary retransmissions and channel contention due to errors in indicating bandwidth using unprotected bits in scrambling sequences and service fields.

Innovation Solution

A method to determine bandwidth for communication by utilizing bits in the scrambling sequence and service field of a PPDU, allowing for continued negotiation and error handling to avoid discarding frames, thereby reducing retransmissions and conserving air interface resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If bandwidth indication bits in service field are used without protection, then bandwidth negotiation can be performed, but check errors occur leading to unnecessary frame discarding and retransmission

Engineering Contradiction:
Improvebandwidth negotiation efficiencyVSAvoidbandwidth indication accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing CRC check on bandwidth indication bits before discarding the frame. The receiving device checks the validity of bandwidth indication information in advance using CRC verification, and only discards the frame when the check fails. This prevents premature discarding due to undetected errors and allows recovery through alternative bandwidth determination methods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements beforehand cushioning by providing backup mechanisms for bandwidth determination. When CRC check fails on bandwidth indication bits, the system has pre-prepared alternative methods including using bandwidth information from other fields, default bandwidth values, or negotiation protocols to ensure continuous operation without immediate retransmission.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Measurement precision

If frames are discarded upon check error in bandwidth bits, then reliable error detection is achieved, but unnecessary retransmissions and channel contention increase

Engineering Contradiction:
Improveerror detection accuracyVSAvoidretransmission delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs CRC verification as a preliminary check before frame discarding. This allows the system to confidently identify genuine errors while avoiding premature discarding of valid frames, thereby reducing unnecessary retransmissions and associated delays.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the receiving device can send acknowledgment or request retransmission only when necessary. By using CRC check results to guide the decision-making process, the system provides accurate feedback to the transmitting device, avoiding unnecessary retransmissions while ensuring reliable error correction when needed.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4294077B1Bandwidth determination method, device, storage medium, and program product
Publication Date: 2025.07.30 HUAWEI TECH CO LTD
  • EP4294077B1 patent drawingFigure 1
  • EP4294077B1 patent drawingFigure 2
  • EP4294077B1 patent drawingFigure 3A

AI summary

A bandwidth determining method, a device, a storage medium, and a program product are provided. In the bandwidth determining method, a first device receives a physical layer protocol data unit PPDU from a second device, where the PPDU is used to determine a scrambling sequence and a service field, and a first group of bits in the scrambling sequence and a second group of bits in the service field indicate a bandwidth. Then, if a check error occurs in the second group of bits, the first device determines a bandwidth for communication between the first device and the second device based on the first group of bits. When the check error occurs in the second group of bits, determining of the bandwidth for communication is not abandoned. This avoids unnecessary retransmission or channel contention.