A Millimeter Wave Backscatter Network for Two-Way Communication and Localization (SIGCOMM'23 S1)

Summary

This presentation introduces 'Milback', the first millimeter wave backscatter system for IoT devices, which supports two-way communication and localization. It addresses the challenges of high data rate, high resolution sensing, and low power consumption. The system employs a novel beamforming technique and orientation-assisted modulation scheme. Prototype testing shows promising results in indoor environments, achieving high data rates at low power consumption compared to Bluetooth and previous systems.

Takeaways

• 🌐 The Internet of Things (IoT) paradigm aims to connect everything together, fostering new applications like smart cities, smart industries, and virtual reality.
• 📈 Emerging technologies and applications require high data rate communication, high-resolution sensing or localization, and low power consumption.
• 🚩 Millimeter wave technology offers high network throughput and high-resolution sensing but struggles with high power consumption.
• 🔄 Backscatter communication is a technique that allows devices to communicate by reflecting or absorbing signals rather than actively transmitting, reducing power consumption.
• 📡 The proposed millimeter wave backscatter system, Milback, supports uplink, downlink, and localization, addressing the limitations of previous systems.
• 🏗️ Milback's innovation lies in a novel beamforming technique and an orientation-assisted modulation scheme, enabling efficient communication.
• 📲 A key challenge is designing a low power beamforming scheme for millimeter wave signals, which suffer from severe path loss.
• 🔄 Milback uses a frequency scanning antenna (FSA) to create beams for signals of different frequencies towards different directions, overcoming the limitations of fixed arrays.
• 📶 The orientation of the node is estimated by analyzing the frequency-dependent beam pattern of the FSA, allowing the AP to align the beams correctly.
• 🔊 Milback enables two-way communication using a two-port FSA and a new modulation scheme that encodes bits to two frequencies.
• 🔋 Compared to Bluetooth and previous millimeter wave backscatter systems, Milback achieves similar data rates with significantly lower power consumption.

Q & A

What is the main focus of the paper presented by the speaker?

The paper focuses on a millimeter wave backscatter network for two-way communication and localization.

What are the three common requirements or constraints of emerging technologies and applications mentioned in the script?

The three common requirements are high data rate communication, high resolution sensing or localization, and low power consumption due to limited power supply.

Why is millimeter wave technology considered a promising solution for high data rate and high resolution sensing?

Millimeter wave technology offers larger licensed and unlicensed bandwidths, which translates to higher network throughput and high resolution sensing capabilities.

What is the main challenge with current millimeter wave radios in terms of power consumption?

Current millimeter wave radios have very high power consumption, which is not ideal for IoT applications that require low power consumption.

How does backscatter communication help in reducing power consumption in millimeter wave systems?

Backscatter communication allows the node device to not actively transmit radio signals but instead reflect or absorb the query signal from the AP, leading to simpler and more power-efficient designs.

What is the innovative aspect of the proposed millimeter wave backscatter system?

The innovation lies in a novel beamforming technique and an orientation-assisted modulation scheme that supports localization, orientation sensing, uplink, and downlink communication altogether.

How does the Van Etta array solve the problem of passive beamforming without consuming power?

The Van Etta array connects each antenna to its mirrored antenna and tunes the phase of transmission lines to reflect signals to a common direction, creating a beam that is always pointing to the transmitter.

What is the second challenge mentioned in the script regarding the use of Frequency Scanning Antennas (FSA)?

The second challenge is estimating the orientation of the node so that the AP can pick the right frequency to align the beams for communication.

How does the proposed system use the Frequency Scanning Antenna (FSA) for two-way communication?

The system uses a two-port FSA and an orientation-assisted modulation scheme called OAQFN, which encodes bits to two frequencies, allowing both uplink and downlink communication.

What are the performance metrics presented for the millimeter wave backscatter system?

The performance metrics presented include the signal-to-noise ratio (SNR) versus distance for both uplink and downlink communication at different data rates.

How does the proposed millimeter wave backscatter system compare to Bluetooth and previous millimeter wave backscatter systems in terms of power efficiency?

Compared to Bluetooth, the proposed system achieves similar data rates while using orders of magnitude lower power consumption. Compared to the previous millimeter wave backscatter system (MMT), it can deliver significantly more data using six times lower energy.