Dinesh Bharadia

HitchHike: Practical Backscatter Using Commodity WiFi

We present HitchHike, a low power backscatter system that can be deployed entirely using commodity WiFi infrastructure. With HitchHike, a low power tag reflects existing 802.11b transmissions from a commodity WiFi transmitter, and the backscattered signals can then be decoded as a standard WiFi packet by a commodity 802.11b receiver. Hitch-Hikes key invention is a novel technique called codeword translation, which allows a backscatter tag to embed its information on standard 802.11b packets by just translating the original transmitted 802.11b codeword to another valid 802.11b codeword. This allows any 802.11b receiver to decode the backscattered packet, thus opening the doors for widespread deployment of low-power backscatter communication using widely available WiFi infrastructure. We show experimentally that HitchHike can achieve an uplink throughput of up to 300Kbps at ranges of up to 34m and ranges of up to 54m where it achieves a throughput of around 200Kbps.

Cutting the Cord in Virtual Reality

Todays virtual reality (VR) headsets require a cable connection to a PC or game console. This cable significantly limits the player’s mobility and hence her/his VR experience. The high data rate requirement of this link (multiple Gbps) precludes its replacement by WiFi. Thus, in this paper, we focus on using mmWave technology to deliver multi Gbps wireless communication between VR headsets and their game consoles. The challenge, however, is that mmWave signals can be easily blocked by the players hand or head motion. We describe novel algorithms and system design that allow such mmWave links to sustain high data rates even in the presence of a blockage, enabling a high quality untethered VR experience.

Enabling Backscatter Communication among Commodity WiFi Radios

We present the first low power backscatter system that can be deployed completely using commodity WiFi infrastructure. With this system, a low power tag reflects existing 802.11b transmissions from a commodity WiFi transmitter, and the backscattered signals can be decoded as a standard WiFi packet by a commodity 802.11b receiver. The key invention is a novel technique called textbf{codeword translation}, which allows a backscatter tag to embed its information on standard 802.11b packets by just translating the original transmitted 802.11b codeword to another valid 802.11b codeword. This allows any 802.11b receiver to decode the backscattered packet, thus opening the doors for widespread deployment of low-power backscatter communication using widely available WiFi infrastructure. We show experimentally that we can achieve an uplink throughput of up to 1Mbps at ranges of up to 8m and ranges of up to 50m where it achieves a throughput of around 100Kbps, which is twice as better than the recently published passive WiFi system.