Common Control Channel in WLAN OFDMA Networks

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Solution Overview

Problem

In wireless communication schemes like OFDMA, there is a need to efficiently provide control information to wireless devices accessing a wireless access point, particularly to manage varying link budgets and automatic gain control settling issues across different devices in a wireless network.

Innovation Solution

The implementation of a common control channel shared among multiple devices in a wireless network, which includes specific tone mappings and message formats to transmit control information such as UL power control, carrier frequency offset, and RU-assignment information, facilitating uniform reception of packets across devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate control channels are assigned to each wireless device, then each device can receive customized control information, but the network complexity and overhead increase significantly

Engineering Contradiction:
Improvecontrol information deliveryVSAvoidcontrol channel structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges control channels by implementing a common control channel that serves multiple wireless devices simultaneously. The access point transmits control information on a shared control channel rather than maintaining separate dedicated control channels for each device, thereby reducing network complexity while maintaining reliable control information delivery to all devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common control channel is designed to serve multiple functions and multiple devices universally. It can carry control information for different device types with varying link budgets, supporting both devices with strong and weak link budgets on the same channel through flexible message formatting and power control mechanisms.

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

2Reliability

If higher transmission power is used for control information, then devices with weak link budgets can receive control information reliably, but devices with strong link budgets may experience saturation and automatic gain control settling issues

Engineering Contradiction:
Improvecontrol information receptionVSAvoidautomatic gain control settling time
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by transmitting control information at different power levels tailored to specific device groups. Devices with weak link budgets receive control information at higher power levels, while devices with strong link budgets receive it at lower power levels, ensuring each device operates in its optimal reception range without causing gain control settling issues.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically changes the transmission power parameter for control information based on device characteristics and channel conditions. The access point adjusts power levels adaptively, selecting appropriate power parameters for different devices or device groups to maintain reliable reception while avoiding saturation effects that cause automatic gain control settling delays.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a common control channel is used for all devices, then network simplicity is improved, but the ability to provide device-specific control information is reduced

Engineering Contradiction:
Improvecontrol channel structureVSAvoiddevice-specific control capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent segments control information into different message types or fields within the common control channel framework. Control messages are structured to include device-specific parameters and identifiers, allowing the common channel to carry both general control information applicable to all devices and specific control information tailored to individual devices or device groups.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The common control channel employs dynamic message formatting and content adaptation. The access point dynamically adjusts the control information content, power levels, and message structures based on real-time device conditions, link budgets, and channel states, enabling the static common channel infrastructure to provide dynamic, device-specific control capabilities.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3091687B1Control channel in WLAN ofdma
Publication Date: 2021.06.23 APPLE INC
  • EP3091687B1 patent drawingFigure 1
  • EP3091687B1 patent drawingFigure 2
  • EP3091687B1 patent drawingFigure 3A

AI summary

Systems and methods of providing control information to wireless devices accessing a wireless network are provided. According to some embodiments, a method of wireless communication is provided. According to the method, a first wireless communication channel is assigned to a first wireless device. A second wireless communication channel is assigned to a second wireless device. A third wireless communication channel is designated for use as a control channel that is common to the first and second wireless devices and control information is transmitted to the first and second wireless devices via the third wireless communication channel.