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Augmented Reality (AR) has been widely hailed as a representative of ultra-high bandwidth and ultra-low latency apps that will be enabled by 5G networks. While single-user AR can perform AR tasks locally on the mobile device, multi-user AR apps, which allow multiple users to interact within the same physical space, critically rely on the cellular network to support user interactions. However, a recent study showed that multi-user AR apps can experience very high end-to-end latency when running over LTE, rendering user interaction practically infeasible. In this paper, we study whether 5G mmWave, which promises significant bandwidth and latency improvements over LTE, can support multi-user AR by conducting an in-depth measurement study of the same popular multi-user AR app over both LTE and 5G mmWave. Our measurement and analysis show that: (1) The E2E AR latency over LTE is significantly lower compared to the values reported in the previous study. However, it still remains too high for practical user interaction. (2) 5G mmWave brings no benefits to multi-user AR apps. (3) While 5G mmWave reduces the latency of the uplink visual data transmission, there are other components of the AR app that are independent of the network technology and account for a significant fraction of the E2E latency. (4) The app drains 66% more network energy, which translates to 28% higher total energy over 5G mmWave compared to over LTE.
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Proceedings of MOBICOM 2021
This paper presents Millimetro, an ultra-low-power tag that can be localized at high accuracy over extended distances. We develop Mil-limetro in the context of autonomous driving to efficiently localize roadside infrastructure such as lane markers and road signs, even if obscured from view, where visual sensing fails. While RF-based localization offers a natural solution, current ultra-low-power local-ization systems struggle to operate accurately at extended ranges under strict latency requirements. Millimetro addresses this challenge by re-using existing automotive radars that operate at mmWave fre-quency where plentiful bandwidth is available to ensure high accuracy and low latency. We address the crucial free space path loss problem experienced by signals from the tag at mmWave bands by building upon Van Atta Arrays that retro-reflect incident energy back towards the transmitting radar with minimal loss and low power consumption. Our experimental results indoors and outdoors demonstrate a scal-able system that operates at a desirable range (over 100 m), accuracy (centimeter-level), and ultra-low-power (< 3 uW).
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- Award ID(s):
- 1823235
- PAR ID:
- 10297822
- Date Published:
- Journal Name:
- Proceedings of the annual International Conference on Mobile Computing and Networking
- ISSN:
- 1543-5679
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
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