Uplink OFDMA Random Access for 20 MHz STA RU Allocation

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Solution Overview

Problem

In IEEE 802.11ax, 20 MHz operating STAs are unable to access resource units (RUs) for uplink OFDMA-based random access (UORA) due to the lack of rules for RU assignment in Trigger frames, resulting in limited opportunities for communication with the access point (AP).

Innovation Solution

A communication apparatus and method that includes a receiver for Trigger frames with fields indicating OFDMA contention window (OCW) minimum and maximum values, and control circuitry to manage UORA procedures, ensuring 20 MHz STAs can access RUs by adjusting the contention window based on priority and availability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If RUs are restricted for 20 MHz operating STAs in 40, 80, 80+80 or 160 MHz OFDMA operation, then interference to non-20 MHz STAs is reduced, but 20 MHz STAs cannot access RUs for random access

Engineering Contradiction:

ImproveinterferenceVSAvoidaccess opportunity

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent segments RUs into different types: restricted RUs (for non-20 MHz STAs only) and non-restricted RUs (available to both 20 MHz and non-20 MHz STAs). This segmentation allows 20 MHz STAs to access specific RUs while non-20 MHz STAs can use all RUs, thereby resolving the contradiction between reducing interference and maintaining access opportunities.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making different RUs have different accessibility properties. Some RUs are designated as restricted with higher quality control for non-20 MHz STAs, while other RUs are non-restricted allowing both types of STAs to access. This local differentiation resolves the contradiction by providing appropriate access conditions in different locations of the frequency spectrum.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If Trigger frames allocate RUs without specific rules for 20 MHz STAs, then flexible resource allocation is achieved, but 20 MHz STAs have limited communication opportunities

Engineering Contradiction:

Improveresource allocation flexibilityVSAvoidcommunication opportunity

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-defining RU types (restricted and non-restricted) in the Trigger frame before STAs attempt random access. The AP preliminarily categorizes RUs based on STA capabilities, ensuring 20 MHz STAs have predetermined access opportunities while maintaining overall allocation flexibility. This resolves the contradiction by establishing access rules in advance.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces dynamics by allowing the AP to dynamically adjust the number and distribution of non-restricted RUs based on network conditions and STA compositions. The Trigger frame can adaptively configure how many RUs are non-restricted versus restricted, balancing flexibility with guaranteed access opportunities for 20 MHz STAs.

Inventive Principle:

Principle #15Dynamics

3Productivity

If all STAs synchronize transmissions to start and end at the same time point, then efficient resource utilization is achieved, but 20 MHz STAs cannot participate in UORA

Engineering Contradiction:

Improveresource utilization efficiencyVSAvoidSTA participation

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent applies universality by creating a Trigger frame structure that serves multiple functions simultaneously: it allocates RUs for synchronized uplink transmissions while also designating specific non-restricted RUs for random access by 20 MHz STAs. This universal Trigger frame structure enables both scheduled synchronized transmission and unsynchronized random access, resolving the contradiction between efficiency and participation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20260040371A1Orthogonal frequency division multiple access communication apparatus and communication method

Publication Date: 2026.02.05 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

An integrated circuit for an access point comprises circuitry configured to: control transmitting of a Trigger frame for allocating resource units (RUs) for random access and another frame including a Random Access parameter element that comprises a first field indicating an OFDMA contention window (OCW) minimum value (OCWmin), wherein the RU(s) include at least one RU that is restricted from being used for a 20 MHz operating station; and control receiving of an Uplink OFDMA-based Random Access (UORA) signal transmitted by the 20 MHz operating station using UORA procedure, the UORA procedure comprising: decrementing an OFDMA Back-Off (OBO) counter to zero when the OBO counter is not greater than a number of available RU(s) for random access in the Trigger frame, the available RU(s) being RU(s) unrestricted from being used for the 20 MHz operating station, or decrementing the OBO counter by the number of available RU(s) for random access.