Overlapping PPDU End-Point Offsets for Staggered Block Acknowledgments
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing overlapping physical layer protocol data units (PPDUs) across multiple access points, leading to potential collisions and inefficiencies in block acknowledgment transmission.
Innovation Solution
The proposed solution involves staggering the end times of overlapping PPDUs by determining a universal end point and applying ordered staggering periods, ensuring that block acknowledgments are transmitted at durations exceeding the BA locking periods for the access points, thereby coordinating the sharing of service periods among multiple access points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple access points transmit overlapping PPDUs with synchronized end times, then spectral efficiency is improved through spatial reuse, but block acknowledgment collisions occur reducing reliability
Solution Approach 1:
The patent segments the block acknowledgment transmissions by introducing offset values that stagger the end times of overlapping PPDUs. Instead of all PPDUs ending simultaneously, each PPDU is assigned a different offset, dividing the simultaneous acknowledgment window into separated time slots. This segmentation prevents collisions while maintaining spatial reuse benefits.
Solution Approach 2:
The patent applies preliminary action by calculating and applying offset values to PPDU end times before the actual transmission occurs. The offsets are determined in advance based on PPDU identifiers, ensuring that block acknowledgments are naturally staggered without requiring real-time coordination or additional control signaling during the transmission phase.
2Productivity
If block acknowledgments are transmitted simultaneously for overlapping PPDUs, then transmission efficiency is improved, but collision probability increases reducing ease of operation
Solution Approach 1:
The patent implements self-service by enabling each PPDU to automatically determine its own staggered end time through a hash function applied to the PPDU identifier. This self-service mechanism eliminates the need for external coordination or complex collision avoidance protocols, as each transmission independently calculates its offset, simplifying the overall system operation while preventing collisions.
Solution Approach 2:
The patent changes the time parameter of PPDU transmissions by introducing dynamic offset values. Instead of fixed synchronized end times, the end time parameter is adjusted based on the calculated offset, transforming the transmission pattern from simultaneous to staggered. This parameter change maintains efficiency while automatically avoiding collisions through mathematical distribution.
3Reliability
If PPDU end times are staggered using offsets, then block acknowledgment collisions are reduced improving reliability, but transmission coordination complexity increases
Solution Approach 1:
The patent uses copying by applying a hash function to replicate the PPDU identifier into an offset value. This mathematical copying process transforms the identifier into a time offset parameter automatically, eliminating the need for complex coordination algorithms. The hash function copies essential information from the identifier while generating the staggered timing parameter in a deterministic and simple manner.
Data Source
AI summary
This disclosure provides methods, components, devices and systems for overlapping physical layer protocol data unit (PPDU) end point offset. Some aspects more specifically relate to staggering the end times of overlapping PPDUs transmitted by multiple access points (APs) such that the corresponding block acknowledgments (BAs) are staggered by durations exceeding BA locking periods for the APs. In some examples, a BA may be transmitted by a wireless station (STA) to an AP a short interframe space (SIFS) after the end time of a PPDU transmitted by the AP. When multiple APs transmit concurrent PPDUs, multiple STAs may accordingly transmit corresponding BAs. By implementing techniques to stagger the BAs, an AP that locks onto a BA and determines that the BA is intended for another AP can receive a next staggered BA intended for the AP.