SAP: an Architecture for Selectively Approximate Wireless Communication
Authors:
Benjamin Ransford,
Luis Ceze
Abstract:
Integrity checking is ubiquitous in data networks, but not all network traffic needs integrity protection. Many applications can tolerate slightly damaged data while still working acceptably, trading accuracy versus efficiency to save time and energy. Such applications should be able to receive damaged data if they so desire. In today's network stacks, lower-layer integrity checks discard damaged…
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Integrity checking is ubiquitous in data networks, but not all network traffic needs integrity protection. Many applications can tolerate slightly damaged data while still working acceptably, trading accuracy versus efficiency to save time and energy. Such applications should be able to receive damaged data if they so desire. In today's network stacks, lower-layer integrity checks discard damaged data regardless of the application's wishes, violating the End-to-End Principle. This paper argues for optional integrity checking and gently redesigns a commodity network architecture to support integrity-unprotected data. Our scheme, called Selective Approximate Protocol (SAP), allows applications to coordinate multiple network layers to accept potentially damaged data. Unlike previous schemes that targeted video or media streaming, SAP is generic. SAP's improved throughput and decreased retransmission rate is a good match for applications in the domain of approximate computing.
Implemented atop WiFi as a case study, SAP works with existing physical layers and requires no hardware changes. SAP's benefits increase as channel conditions degrade. In tests of an error-tolerant file-transfer application over WiFi, SAP sped up transmission by about 30% on average.
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Submitted 13 October, 2015;
originally announced October 2015.
Powering the Next Billion Devices with Wi-Fi
Authors:
Vamsi Talla,
Bryce Kellogg,
Benjamin Ransford,
Saman Naderiparizi,
Shyamnath Gollakota,
Joshua R. Smith
Abstract:
We present the first power over Wi-Fi system that delivers power and works with existing Wi-Fi chipsets. Specifically, we show that a ubiquitous piece of wireless communication infrastructure, the Wi-Fi router, can provide far field wireless power without compromising the network's communication performance. Building on our design we prototype, for the first time, battery-free temperature and came…
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We present the first power over Wi-Fi system that delivers power and works with existing Wi-Fi chipsets. Specifically, we show that a ubiquitous piece of wireless communication infrastructure, the Wi-Fi router, can provide far field wireless power without compromising the network's communication performance. Building on our design we prototype, for the first time, battery-free temperature and camera sensors that are powered using Wi-Fi chipsets with ranges of 20 and 17 feet respectively. We also demonstrate the ability to wirelessly recharge nickel-metal hydride and lithium-ion coin-cell batteries at distances of up to 28 feet. Finally, we deploy our system in six homes in a metropolitan area and show that our design can successfully deliver power via Wi-Fi in real-world network conditions.
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Submitted 26 May, 2015;
originally announced May 2015.