HE WLAN PPDU Padding for Synchronized Multi-Subchannel Transmission
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Solution Overview
Problem
There is no specified method for applying padding to a Physical layer Protocol Data Unit (PPDU) frame format in a High Efficiency WLAN (HEW), which affects the performance and efficiency of wireless networks with multiple Access Points (APs) and Stations (STAs).
Innovation Solution
A method and apparatus for generating padding in a High Efficiency WLAN (HEW) PPDU frame format, where the transmission channel is divided into subchannels, and padding is applied to ensure simultaneous end of transmissions across these subchannels, allowing for efficient data transmission to multiple Stations (STAs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple STAs transmit data simultaneously on different subchannels without padding, then transmission efficiency is improved, but transmission timing becomes unsynchronized causing performance degradation
Solution Approach 1:
The patent changes the parameter of data unit length by introducing variable-length padding to different subchannels. The AP calculates the maximum data unit length among all subchannels and adds padding to shorter ones, transforming the parameter distribution from unequal to equal, thereby achieving simultaneous transmission end times across all subchannels while maintaining high transmission efficiency.
2Reliability
If padding is added to all subchannels to ensure simultaneous transmission end, then transmission synchronization is improved, but transmission overhead increases
Solution Approach 1:
The patent applies local quality by differentiating the padding application strategy across subchannels. Instead of uniformly adding padding to all subchannels, the system identifies subchannels that actually need padding (those with shorter data units) and applies padding only to them. This localized approach maintains transmission synchronization while minimizing unnecessary overhead on subchannels that already have sufficient data length.
3Reliability
If the AP waits for the longest data unit to complete before transmitting on other subchannels, then transmission synchronization is improved, but transmission time increases
Solution Approach 1:
The patent implements preliminary action by having the AP calculate and determine the maximum data unit length among all subchannels before actual transmission begins. The AP prepares the padding lengths for each subchannel in advance, so that when transmission starts, all subchannels can transmit simultaneously and end at the same time without requiring any subchannel to wait for others, thus eliminating transmission time delays.
Data Source
AI summary
The present invention relates to a Physical layer Protocol Data unit (PPDU) format including a padding. According to one aspect of the present invention, a method for transmitting data to a plurality of stations on a transmission channel by an Access Point in a WLAN may be provided. The transmission channel may be divided into a plurality of subchannels allocated to the plurality of stations. The method may include generating padding having a length individually for each of one or more subchannels to which paddings are applied among the plurality of subchannels, the length of the padding making transmissions end simultaneously on the plurality of subchannels, and transmitting a PPDU frame including a data unit without the padding or a data unit added with the padding for each of the plurality of subchannels to the plurality of stations on the transmission channel.