Multi-AP Leading Signals for Synchronized Concurrent Transmissions
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Solution Overview
Problem
Aligning the start time of shared AP transmissions with that of the sharing AP in multi-access point networks is challenging due to strict timing requirements, which are difficult to implement and often require specific STA capabilities like PoP detection, complicating the design and power consumption.
Innovation Solution
A method and system that utilize a leading signal transmitted by a second AP to align the start time of its transmission with that of a first AP, allowing the second station to enter an idle state without requiring PoP detection, by using a coordination control frame and a short interframe space (SIFS) for decoding and parsing, followed by an idle state before receiving the subsequent PPDU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a delay is introduced in the shared AP's transmission to allow more time for preparation, then timing alignment becomes easier to achieve, but the STA must support specific capabilities like PoP detection which increases device complexity and power consumption
Solution Approach 1:
The sharing AP transmits an M-AP Trigger frame in advance to notify the shared AP of the upcoming coordinated transmission. This preliminary notification allows the shared AP to prepare its transmission without requiring the STA to implement complex PoP detection capabilities, as the timing is pre-coordinated through the trigger frame
Solution Approach 2:
The M-AP Trigger frame acts as an intermediary message that carries timing information and coordination parameters between the sharing AP and shared AP. This intermediary mechanism enables precise timing alignment while keeping the STA design simpler, as the coordination is handled at the AP level through the trigger frame rather than requiring complex STA-side PoP detection
2Reliability
If PoP detection capability is implemented in STA to support delayed transmission, then transmission coordination becomes possible, but power consumption increases and design becomes more complex
Solution Approach 1:
The shared AP autonomously determines its transmission timing based on the M-AP Trigger frame it receives, without requiring the STA to actively detect or manage packet overlaps. The STA simply follows standard reception procedures, eliminating the need for power-consuming PoP detection functionality while maintaining reliable coordination
3Productivity
If strict timing control is implemented to align transmissions, then concurrent communication efficiency improves, but implementation difficulty increases
Solution Approach 1:
The M-AP Trigger frame conveys specific timing parameters and offsets that define when the shared AP should transmit relative to the sharing AP. By parameterizing the timing relationship in the trigger frame, the system achieves precise concurrent transmission coordination without requiring complex hardware timing circuits, making implementation more straightforward
Data Source
AI summary
A multi-access point coordination signal transmission method includes receiving a coordination control frame transmitted from a first access point (AP) by a second AP, decoding and parsing the coordination control frame by the second AP during a short interframe space, transmitting a leading signal from a second AP to a second station when a first packet protocol data unit (PPDU) is transmitted from the first AP to a first station, entering an idle state by the second station after the leading signal is completely received, and receiving a second PPDU transmitted from the second AP by the second station after leaving the idle state