Enabling Practical Backscatter Communication for On-body Sensors

By Pengyu Zhang, Mohammad Rostami, Pan Hu, Deepak Ganesan. Conference on Applications, Technologies, Architectures, and Protocols for Computer Communication, 2016

315 citations recorded by the source corpus.

In this paper, we look at making backscatter practical for ultra-low power on-body sensors by leveraging radios on existing smartphones and wearables (e.g. WiFi and Bluetooth). The difficulty lies in the fact that in order to extract the weak backscattered signal, the system needs to deal with self-interference from the wireless carrier (WiFi or Bluetooth) without relying on built-in capability to cancel or reject the carrier interference. Frequency-shifted backscatter (or FS-Backscatter) is based on a novel idea --- the backscatter tag shifts the carrier signal to an adjacent non-overlapping frequency band (i.e. adjacent WiFi or Bluetooth band) and isolates the spectrum of the backscattered signal from the spectrum of the primary signal to enable more robust decoding. We show that this enables communication of up to 4.8 meters using commercial WiFi and Bluetooth radios as the carrier generator and receiver. We also show that we can support a range of bitrates using packet-level and bit-level decoding methods. We build on this idea and show that we can also leverage multiple radios typically present on mobile and wearable devices to construct multi-carrier or multi-receiver scenarios to improve robustness. Finally, we also address the problem of designing an ultra-low power tag that can frequency shift by 20MHz while consuming tens of micro-watts. Our results show that FS-Backscatter is practical in typical mobile and static on-body sensing scenarios while only using commodity radios and antennas.

Subfields: Aerospace Engineering, Biomedical Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/8347fa4ad280baf119580cc680fd85ddb16d7236

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Aerospace Engineering

1. Ying-Chang Liang
2. Dusist Niyato
3. Rui Zhang
4. Dong In Kim
5. Xiao Lu
6. Gang Yang
7. Yiyang Pei
8. Dinh Thai Hoang

In Biomedical Engineering

1. Rui Zhang
2. Dusist Niyato
3. Dong In Kim

In Electrical and Electronic Engineering

1. Rui Zhang
2. Ying-Chang Liang
3. Gang Yang
4. Dusist Niyato
5. Dong In Kim
6. Yiyang Pei
7. Xiao Lu
8. Dinh Thai Hoang

Citations in the corpus

• Ambient Backscatter Communications: A Contemporary Survey (2017, methodology): “Another technique which aims to reduce self-interference at the backscatter receiver is introduced in [139], named frequency-shifted backscatter.”
• HitchHike: Practical Backscatter Using Commodity WiFi (2016, unknown): “To tackle this challenge, like recent work [20, 35], HitchHike uses frequency shifting where the backscattered packet is shifted and transmitted on an adjacent non-overlapping WiFi channel.”
• PLoRa: a passive long-range data network from ambient LoRa transmissions (2018, methodology): “FS-Backscatter [49] uses a ring oscillator to generate the required signal plan for frequency shifting.”
• Modulation in the Air: Backscatter Communication Over Ambient OFDM Carrier (2017, methodology): “Compared to both FS techniques in [13] and [14] each of which produces two sidebands, the FS techniques in [15] and [16] ensure that only the desired backscatter sideband is produced and other spurious sidebands are eliminated.”
• Cooperative Ambient Backscatter Communications for Green Internet-of-Things (2018, background): “A frequency-shifted backscatter (FSbackscatter) system is proposed in [10] for on-body sensor applications, which suppresses the direct-link interference by shifting the backscattered signal to a clean band that does not overlap with the direct-link signal.”
• Inter-Technology Backscatter: Towards Internet Connectivity for Implanted Devices (2016, background): “Since the minimum resolution at which the bits are conveyed is greater than a Wi-Fi packet, this limits the bit rate to 100–1000 bps. Recent work on FS-Backscatter [50] combines this packet-level backscatter approach with double sideband subcarrier modulation [13, 28, 29].”