VHT-SIG-B Field in Null Data Packets for Interference Management

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current wireless communication systems face challenges in efficiently utilizing Very High Throughput Signal B (VHT-SIG-B) fields in null data packets (NDPs) to manage interference and maintain a unified preamble structure, particularly in MIMO systems, where retaining the VHT-SIG-B field is proposed to enhance interference determination and processing time for beamforming feedback.

Innovation Solution

Incorporating the VHT-SIG-B field in NDPs with specific content options such as repeated VHT-LTF symbols, dedicated bit patterns, BSSID, or NDP sequence numbers to provide useful information for interference assessment and beamforming adjustments, allowing for robust MU-MIMO reception and unified IEEE 802.11ac preamble structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the VHT-SIG-B field is removed from NDPs to simplify the preamble structure, then device complexity is reduced, but interference management capability deteriorates

Engineering Contradiction:
Improvepreamble structure complexityVSAvoidinterference management capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent extracts only the essential signaling function from the VHT-SIG-B field by placing a simplified signal indicator (one or two bits) in the L-SIG field of NDPs, rather than including the complete VHT-SIG-B field. This extraction approach maintains interference management capability while significantly reducing preamble complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter representation by encoding interference management information in a compact form (1-2 bits in L-SIG field) rather than using the full VHT-SIG-B field structure. This parameter transformation achieves the same functional goal with reduced complexity.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the VHT-SIG-B field is retained in NDPs to maintain unified preamble structure, then preamble structure uniformity is improved, but processing time increases

Engineering Contradiction:
Improvepreamble structure uniformityVSAvoidprocessing time for beamforming feedback
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent extracts only the critical signal indicator from the VHT-SIG-B field and places it in the L-SIG field, eliminating the need for receivers to process the complete VHT-SIG-B field while maintaining structured preamble organization.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary encoding of interference management information in the L-SIG field before the receiver needs to process it, allowing stations to quickly determine signal type and adjust processing accordingly, thereby reducing overall processing time.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If comprehensive information is placed in the VHT-SIG-B field of NDPs to improve interference determination accuracy, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveinterference determination accuracyVSAvoidinformation processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms comprehensive interference determination information into a compact 1-2 bit indicator in the L-SIG field, which still provides sufficient precision for interference determination while dramatically reducing processing complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a partial representation (1-2 bits) of the full VHT-SIG-B field information, which is sufficient for the required interference determination accuracy without the need to process all possible information elements.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2601768B1VHT-SIG-B FIELD IN NULL DATA PACKETS (NDPs)
Publication Date: 2016.05.11 QUALCOMM INC
  • EP2601768B1 patent drawingFigure 1
  • EP2601768B1 patent drawingFigure 2
  • EP2601768B1 patent drawingFigure 3

AI summary

Certain aspects of the present disclosure relate to methods and apparatus for using information in a Very High Throughput Signal B (VHT-SIG-B) field in the preamble of a null data packet (NDP). Retaining the VHT-SIG-B field in NDPs offers several advantages, such as maintaining a unified IEEE 802.11ac preamble structure, providing for 4 ?s extra time to process beamforming feedback, and being able to use information in the VHT-SIG-B field to determine a level of interference in the NDP.