Cross-Band PPDU Alignment in Multi-AP NSTR Coordination
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Solution Overview
Problem
Existing Multi-Access Point Coordination (MAPC) and Multi-Link-Device (MLD) operations face challenges in coordinating the start and/or end alignment of Physical Layer Protocol Data Units (PPDUs) across multiple frequency bands, particularly in Non-Simultaneous Transmit and Receive (NSTR) communication scenarios where Stations (STAs) are connected to multiple physical Access Points (APs) operating on different frequency bands.
Innovation Solution
Implementing a cross-band MAPC coordination function that uses a CG controller and CG leaders to synchronize the end times of PPDUs across multiple APs, leveraging IEEE 802.1AS standard for time synchronization and evaluating AP properties to determine optimal data distribution, enabling coordinated group leaders to assign time slots for NSTR communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current MAPC technologies are used without cross-band coordination, then device complexity is reduced, but throughput is limited and latency increases when communicating with NSTR Stations across multiple frequency bands
Solution Approach 1:
The patent introduces a coordination function that acts as an intermediary between multiple APs operating on different frequency bands. This intermediary mechanism enables cross-band PPDU alignment by coordinating transmission timing across bands, thereby improving throughput for NSTR Stations without requiring each AP to independently manage complex synchronization logic.
Solution Approach 2:
The patent modifies the MAPC coordination parameters to support cross-band operations. By changing the coordination scope from single-band to multi-band and introducing new parameters for PPDU alignment across frequency bands, the system achieves improved throughput while managing complexity through standardized parameter extensions.
2Loss of time
If cross-band PPDU alignment is implemented, then latency is reduced for NSTR Stations, but the coordination mechanism becomes more complex
Solution Approach 1:
The patent segments the coordination mechanism into distinct functional components: a coordination function that manages cross-band timing, individual APs that execute transmissions, and NSTR Stations that receive synchronized PPDUs. This segmentation allows the complex latency reduction functionality to be distributed and managed systematically, reducing overall system complexity.
Solution Approach 2:
The patent implements preliminary coordination actions where APs pre-calculate and synchronize their transmission timing before actual data transmission. By establishing the coordination framework and timing parameters in advance, the system reduces latency for NSTR Stations without requiring complex real-time coordination decisions during data transmission.
3Reliability
If MAPC and MLD operations are combined, then network performance is improved, but existing MAPC does not support cross-band coordination
Solution Approach 1:
The patent extends the MAPC coordination function to serve multiple purposes: it maintains support for single-band operations while adding cross-band coordination capabilities. This universal coordination function can operate in both single-band and multi-band modes, enabling reliable network performance improvement through combined MAPC and MLD operations without sacrificing existing adaptability.
Data Source
AI summary
Access Point (AP) coordination and, specifically, Multi-AP Coordination (MAPC) for Non-Simultaneous Transmit and Receive (NSTR) cross-band Physical Layer Protocol Data Unit (PPDU) alignment may be provided. The coordination can include determining to communicate with a client using MAPC Multi-Link-Device (MLD) operation. A first AP operating on a first band with a first link to the client and a second AP operating on second band with a second link to the client may be determined to communicate with the client. The first AP and the second AP may be coordinated to send one or more PPDUs with synchronized end times. The first AP may be instructed to transmit to the client via the first link and the second AP may be instructed to transmit to the client via the second link according to the coordination.