Multi-User Spatially Multiplexed Packets for WLAN Sensing
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Solution Overview
Problem
Existing multi-user physical layer packets in wireless local area networks (WLAN) sensing suffer from unsatisfactory performance and interference issues, particularly when spatially multiplexing sensing and non-sensing devices, leading to reduced throughput and sensing accuracy.
Innovation Solution
A method and apparatus for transmitting multi-user physical layer packets with a data field left empty for sensing devices, controlling emission patterns to ensure low interference, and using different transmitter configurations for each stream to minimize interference and enable efficient channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-user physical layer packets are used to serve both sensing and non-sensing devices, then communication capacity is improved, but sensing performance and accuracy deteriorate due to interference
Solution Approach 1:
The patent segments the multi-user packet into distinct spatial streams, with one stream designated for sensing devices and another for non-sensing devices. Each stream is independently configured and transmitted through separate spatial channels, allowing simultaneous service to different device types without mutual interference.
Solution Approach 2:
The patent applies different transmission configurations to different spatial streams within the same packet. The sensing stream uses parameters optimized for channel estimation and sensing accuracy, while the non-sensing stream uses parameters optimized for data throughput, thereby tailoring transmission quality to local requirements of each device type.
2Productivity
If spatial multiplexing is applied to transmit multiple streams, then communication efficiency is improved, but interference between streams increases
Solution Approach 1:
The patent resolves stream interference by transitioning from frequency or time domain separation to spatial domain separation. Multiple streams are transmitted simultaneously in the same time-frequency resources but are separated through spatial multiplexing using multiple antennas and spatial processing techniques at the receiver.
Solution Approach 2:
The patent introduces spatial processing and signal separation techniques as intermediaries between the transmitted streams and the receivers. These intermediaries enable the receiver to distinguish and separately process signals from different streams, preventing harmful interference even when streams share the same physical medium.
3Device complexity
If the same transmitter configuration is used for all streams, then device complexity is reduced, but sensing performance deteriorates
Solution Approach 1:
The patent configures different transmission parameters, power levels, and signal characteristics for the sensing stream versus the data stream. The sensing stream uses configurations specifically optimized for channel estimation accuracy and sensing measurements, while the data stream uses configurations optimized for throughput, thereby achieving optimal performance for each function without compromising the other.
Data Source
AI summary
A method is disclosed of a transmitter configured to transmit more than one spatially multiplexed streams having a multi-user physical layer packet for a plurality of users. The plurality of users includes a first type user and a second type user. A first stream is assigned for the first type user and a second stream is assigned for the second type user. The method includes leaving a data field of the physical layer packet empty for the first type user, providing second type user emission strength (in a spatial direction towards the first type user) that falls below a threshold value by controlling a spatial emission pattern associated with the second type user for the physical layer packet, and transmitting the physical layer packet.