Coordinated TXOP Sharing Between Access Points Using C-TDMA
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless local area networks (WLANs) lack consensus on frame formats and coordination rules for Coordinated Time Division Multiple Access (C-TDMA) among access points (APs) to efficiently share a transmission opportunity (TXOP), which hinders network throughput, management of time-sensitive traffic, and interference mitigation.
Innovation Solution
Innovative frame formats and methodologies are introduced to support C-TDMA, including new polling and triggering mechanisms, enabling APs to coordinate TXOP sharing through frame exchanges and resource negotiation, allowing efficient time allocation and management of wireless spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional WLAN contention-based access is used, then devices can independently access the wireless medium, but network throughput and coordination among APs deteriorate
Solution Approach 1:
The patent introduces a coordinator AP that acts as an intermediary to manage TXOP sharing among multiple APs. The coordinator AP receives resource requests from participant APs, allocates time resources, and coordinates transmissions, thereby improving network throughput through centralized control while managing coordination complexity through a dedicated mediator role.
Solution Approach 2:
The patent replaces the traditional distributed contention-based mechanical access mechanism with a scheduled time-division multiple access (TDMA) system. Instead of APs competing for channel access through contention, time slots are pre-allocated and scheduled, substituting the random mechanical contention process with a deterministic scheduling mechanism that improves throughput.
2Adaptability or versatility
If TXOP sharing among APs is implemented without standardized frame formats, then resource allocation flexibility improves, but frame format compatibility and coordination reliability worsen
Solution Approach 1:
The patent segments the coordination process into distinct standardized frame types: resource request frames, resource allocation frames, and data transmission frames. Each frame type has a specific standardized format that defines its structure and content, allowing flexible resource allocation through different frame combinations while ensuring reliability through standardized interoperable formats.
Solution Approach 2:
The patent uses parameter fields within standardized frame formats to dynamically adjust resource allocation. By changing parameters such as time slot duration, frequency resource allocation, and transmission power levels within the standardized frame structure, the system achieves flexible resource allocation while maintaining coordination reliability through consistent parameter interpretation across all APs.
3Speed
If APs transmit simultaneously without coordination, then individual AP transmission speed is maintained, but interference levels and overall network efficiency worsen
Solution Approach 1:
The patent implements periodic time-slot-based transmissions where each AP transmits data in its allocated time slot rather than continuously or simultaneously. This periodic action structure ensures that transmissions are time-separated, preventing interference while maintaining high transmission speeds during each allocated slot. The coordinator AP manages the periodic schedule to optimize overall network efficiency.
Data Source
AI summary
Methods and apparatus for coordinated time domain multiple access (C-TDMA) sharing of a wireless frequency resource by a first access point (AP) of a device. In a method, the first AP obtains a Transmit Opportunity (TXOP) for the frequency resource and transmits a Buffer Status Report Poll (BSRP) trigger frame addressed to at least a second AP. In this example, the BSRP trigger frame includes control information indicating a time allocation of the TXOP available for use by the second AP. In response to the BSRP trigger frame, the first AP receives a response frame (e.g., a QoS Null frame) including resource request information of the second AP with respect to the time allocation of the TXOP. The control information may include one or more of a duration of the time allocation, a reference bandwidth, or a start time of the time allocation.