Antenna Switching Ranging Protocol for Multipath Accuracy
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Solution Overview
Problem
Current wireless communication systems face challenges in accurately estimating distances between devices due to limitations in ranging protocols, particularly in multipath environments, where direct path estimation is hindered by noise and random errors.
Innovation Solution
The implementation of antenna switching during ranging procedures, where wireless devices employ multiple transmit and receive antennas to transmit and receive ranging messages, allowing for improved channel estimation and reduced multipath issues through spatial diversity, by using different antenna pairs to calculate round trip times and discard outliers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ranging protocols are used with single antenna transmission, then device complexity is low, but ranging accuracy deteriorates due to multipath interference and noise
Solution Approach 1:
The patent implements dynamic antenna switching during the ranging procedure, where the transmitting device switches between different antennas to send different ranging messages (FTM frames, NDP frames, or uplink sounding frames). This dynamic reconfiguration allows the system to exploit spatial diversity and select optimal antenna pairs for transmission and reception, thereby improving ranging accuracy while managing complexity through controlled switching sequences
Solution Approach 2:
The patent introduces a spatial dimension to the ranging process by utilizing multiple antennas and antenna pairs. Instead of single-antenna transmission, the system transmits ranging messages through different spatial paths using antenna switching, creating multiple measurement opportunities from different spatial perspectives. This dimensional expansion enables the system to overcome multipath interference and improve measurement precision
2Measurement precision
If multiple antenna pairs are used for ranging measurements, then measurement precision improves through spatial diversity, but loss of time increases due to multiple transmission rounds
Solution Approach 1:
The patent maintains continuous ranging measurements by implementing antenna switching within a unified ranging procedure framework. Instead of separate independent measurements, the system continuously switches antennas and transmits different types of ranging messages (FTM frames, NDP frames, uplink sounding frames) in sequence, ensuring that the ranging process remains ongoing and productive throughout the measurement period, thereby reducing overall time loss
Solution Approach 2:
The patent employs multiple types of ranging messages (FTM frames, NDP frames, uplink sounding frames) that can serve multiple functions within the same ranging procedure. These different message types allow the system to gather ranging information through various mechanisms simultaneously, making the ranging procedure more efficient and reducing the total time required to achieve accurate measurements through spatial diversity
Data Source
AI summary
This disclosure provides systems, methods and apparatuses, including computer programs encoded on computer storage media, for ranging procedures performed using antenna switching. In one aspect, a device initiating a ranging procedure may transmit a ranging request, which may include antenna switching capabilities of the initiating device, a request for antenna switching by a responding device during the ranging procedure, or both. Ranging signaling may be communicated between the initiating device and the responding device using different transmit antennas, receive antennas, or both. In some implementations, ranging messages transmitted by the responding device may include transmit antenna indices used for transmission of different ranging messages, and receive antenna indices used for reception of different ranging response messages. The initiating device may estimate a range relative to the responding device based on round trip times (RTTs) associated with different antenna pairs used during the ranging procedure.