Passive Backscatter Uplink/Downlink Sounding with Antenna-State Switching
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Solution Overview
Problem
Passive Backscatter Devices (BKDs) face limitations in performing channel sounding due to their limited power and processing capabilities, requiring new mechanisms for managing interference and switching between antenna states, especially in uplink operations with multiple Access Points (APs).
Innovation Solution
Implementing coordinated uplink and downlink sounding through the use of a Null Data Packet Announcement-Backscatter Device (NDPA-BKD) frame to manage interference and maximize Signal-to-Interference-plus-Noise Ratio (SINR) by setting BKDs to different antenna states, allowing APs to perform channel estimation and beamforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If passive BKDs perform channel sounding with multiple antenna states, then channel estimation accuracy is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent segments the channel sounding process into multiple sequential phases: announcement phase (NDPA-BKD frame transmission), sounding phase (multiple sounding frames with different antenna states), and feedback phase. This segmentation allows the passive BKD to perform complex multi-antenna channel sounding by breaking it into manageable steps, reducing the instantaneous processing complexity while maintaining measurement precision.
Solution Approach 2:
The patent implements preliminary action by transmitting an NDPA-BKD frame before the actual sounding frames. This announcement frame预先 informs receiving devices about the upcoming sounding sequence, antenna states, and timing. This preliminary information preparation reduces the real-time processing burden on passive BKDs during the actual sounding measurement phase.
2Measurement precision
If multiple sounding frames are transmitted with different antenna states, then channel sounding performance is improved, but interference management becomes more difficult
Solution Approach 1:
The patent employs periodic action by transmitting sounding frames in a structured sequence with specific time intervals between them. Each sounding frame corresponds to a specific antenna state in a periodic pattern. This periodic structure allows receiving devices to predict and manage interference from multiple antenna transmissions, improving channel sounding performance while controlling interference through regular timing patterns.
Solution Approach 2:
The patent implements feedback mechanisms where receiving devices provide channel sounding feedback to the passive BKD after receiving multiple sounding frames with different antenna states. This feedback loop enables the system to adjust transmission parameters and antenna states based on observed interference patterns, optimizing channel estimation accuracy while managing interference from multiple simultaneous transmissions.
3Adaptability or versatility
If uplink sounding is performed with multiple APs, then network coverage is improved, but signal-to-interference-plus-noise ratio decreases
Solution Approach 1:
The patent applies local quality by enabling different Access Points to use different antenna states and transmission parameters tailored to their local environment and user requirements. Each AP can optimize its sounding transmission independently, allowing improved network coverage through multiple APs while maintaining reliable SINR by adapting local transmission characteristics rather than using uniform parameters across all APs.
Data Source
AI summary
Coordinated sounding of passive devices and, specifically, uplink and downlink sounding to Ambient Power (AMP) Backscatter Devices (BKDs) may be provided. Channel sounding with BKDs can include sending a sounding announcement frame to a BKD a receiving device, wherein the sounding announcement frame announces a plurality of sounding frames for channel sounding over a plurality of antenna states of the BKD. A first sounding frame is sent to the BKD and the receiving device, wherein the BKD is set to a first state of the plurality of antenna states. Then, a second sounding frame is sent to the BKD and the receiving device, wherein the BKD is set to a second state of the plurality of antenna states. Channel sounding feedback is received from the receiving device.