IMDEA Networks Institute Hans Suys and Bjrn Debaillie Imec Belgium - PowerPoint PPT Presentation

Adrian Loch, Hany Assasa, Joan Palacios, and Joerg Widmer IMDEA Networks Institute Hans Suys and Björn Debaillie Imec Belgium 1

2 December 14, 2017 Zero Overhead Device Tracking Paper Lamp Searchlight Omnidirectional Wireless Communication < 6 GHz

2 December 14, 2017 Zero Overhead Device Tracking Paper Lamp Searchlight Directional Wireless Communication Omnidirectional Wireless > 6 GHz (mmWave) Communication < 6 GHz

Zero Overhead Device Tracking December 14, 2017 3 Node A Node B Mechanism as in IEEE 802.11ad

Zero Overhead Device Tracking December 14, 2017 3 Node A Mechanism as in IEEE 802.11ad Node B

Zero Overhead Device Tracking December 14, 2017 3 Node A Mechanism as in IEEE 802.11ad Node B

Zero Overhead Device Tracking December 14, 2017 3 Node A Node B Approaches in Related Work

Zero Overhead Device Tracking December 14, 2017 3 Node A Approaches in Related Work Node B

Zero Overhead Device Tracking December 14, 2017 3 Node A Approaches in Related Work Node B

Zero Overhead Device Tracking December 14, 2017 4 Node A Node B Our multi-lobe approach

Zero Overhead Device Tracking December 14, 2017 4 Node A Node B Our multi-lobe approach

Zero Overhead Device Tracking December 14, 2017 4 Node A Node B Our multi-lobe approach

Zero Overhead Device Tracking December 14, 2017 4 Node A Node B Our multi-lobe approach

Zero Overhead Device Tracking December 14, 2017 4 Node A Our multi-lobe approach

5 December 14, 2017  Zero Overhead Device Tracking  Exploiting Preambles in 802.11ad  Golay Sequences for Phase Detection  Practical Challenges Zero Overhead Device Tracking  Preamble Robustness  Handling Obstacles  Evaluation  Practical Results  Simulation Results  Conclusions

6 www.networks.imdea.org The core of our mechanism +1 -1 TX RX

7 December 14, 2017 Receiving half of the preamble using multilobe pattern  No modification to the transmitter nor the operation of IEEE 802.11ad  Modified receiver fully backward compatible with regular devices  Receiver uses misalignment information for both TX and RX steering Acknowledgment STF CEF Payload Zero Overhead Device Tracking 3.63 µs Data STF CEF Payload 1.2 µs

7 December 14, 2017 Receiving half of the preamble using multilobe pattern  No modification to the transmitter nor the operation of IEEE 802.11ad  Modified receiver fully backward compatible with regular devices  Receiver uses misalignment information for both TX and RX steering Acknowledgment STF CEF Payload Zero Overhead Device Tracking 3.63 µs Data STF CEF Payload 1.2 µs TX RX TX RX

7 December 14, 2017 Receiving half of the preamble using multilobe pattern  No modification to the transmitter nor the operation of IEEE 802.11ad  Modified receiver fully backward compatible with regular devices  Receiver uses misalignment information for both TX and RX steering Acknowledgment STF CEF Payload Zero Overhead Device Tracking 3.63 µs Data STF CEF Payload 1.2 µs TX RX Pattern switch time is below 50 ns on state-of-the-art antennas and can be as low as 50 ps TX RX

8 December 14, 2017 Designing two-lobe beampatterns to track devices  Relative phase-shift among the two lobes is designed to be 180º  Receiver receives part of the preamble using the two-lobe beampattern  Comparing first and second half of preamble reveals orientation Zero Overhead Device Tracking Two-lobe beampatterns are feasible using analog beamforming

9 December 14, 2017 Detecting phase shift among preamble halves  Direct phase comparison is challenging due to beam pattern change  Properties of Golay sequences allow for robust phase shift detection  Correlation results in a positive (0º shift) or negative (180º shift) spike Obtain Golay sequence via one-lobe and two-lobe beam pattern Zero Overhead Device Tracking Compute cross-correlation of both sequences Rotation to the left Well aligned Rotation to the right

10 www.networks.imdea.org Making our approach work on practical hardware

11 December 14, 2017 Packet detection with only part of the preamble STF  A receiver may only receive half of the STF in the worst case  We show in practice that an 802.11ad decoder works with such an STF  Receiver can equalize packet since CEF is received with regular pattern TX: COTS 802.11ad Zero Overhead Device Tracking RX: Keysight Wideband Waveform Center

12 December 14, 2017 Obstacles and misalignments are radically different  In case of antenna misalignment, the current path is still available  In case of blockage, the nodes must find an entirely new path  802.11ad beacon sweeps address both but we focus on misalignment Zero Overhead Device Tracking

12 December 14, 2017 Obstacles and misalignments are radically different  In case of antenna misalignment, the current path is still available  In case of blockage, the nodes must find an entirely new path  802.11ad beacon sweeps address both but we focus on misalignment Zero Overhead Device Tracking   Our mechanism can track both paths individually

12 December 14, 2017 Obstacles and misalignments are radically different  In case of antenna misalignment, the current path is still available  In case of blockage, the nodes must find an entirely new path  802.11ad beacon sweeps address both but we focus on misalignment Zero Overhead Device Tracking   Our mechanism can track Finding the reflected path is both paths individually a separate problem

13 www.networks.imdea.org Practical and simulative results

14 December 14, 2017 Implementation on phased antenna array at IMEC  Highly flexible 60 GHz frontend featuring 2x8 antenna elements  Antenna allows for phase and amplitude control of each element  Testbed is fully controlable from Matlab, allowing for rapid prototyping TX Antenna RX Antenna Zero Overhead Device Tracking Control PC Oscilloscope Differential IQ Signal Generator Differential IQ Control PC and TX Equipment RX Equipment

15 December 14, 2017 Implementation on phased antenna array at IMEC  One side of the link rotates according to real-world gyroscope traces  Automatic beam-steering adjustment based on correlation output  Steering error always below 5º which results in up to 2x throughput gain Zero Overhead Device Tracking Seamless and fast error recovery Walking movement at indoor speed

16 December 14, 2017 We achieve significant performance improvements  We measure performance both in terms of throughput and angle error  Device tracking can maintain a high rate in spite of movement/rotation  The angle error is below the outage threshold even for strong rotations Zero Overhead Device Tracking Periodic controlled rotation of one of the ends of the link

17 December 14, 2017 Full protocol stack implementation on NS-3 and Matlab  Matlab symbol-level simulation including raytracer and 60 GHz model  NS-3 packet-level simulation in direct execution mode with TCP Cubic  Large number of randomly generated scenarios using gyroscope traces Zero Overhead Device Tracking 802.11ad suffers massive SNR drops due Our approach reduces to rotation whereas our approach the angle error to below continuously adapts to such rotations 3º in almost all cases

17 December 14, 2017 Full protocol stack implementation on NS-3 and Matlab  Matlab symbol-level simulation including raytracer and 60 GHz model  NS-3 packet-level simulation in direct execution mode with TCP Cubic  Large number of randomly generated scenarios using gyroscope traces Zero Overhead Device Tracking 802.11ad suffers massive SNR drops due Our approach reduces to rotation whereas our approach the angle error to below continuously adapts to such rotations 3º in almost all cases

18 www.networks.imdea.org Summary of our insights

Zero Overhead Device Tracking December 14, 2017 19

19 December 14, 2017  Goal: track movement and rotation of IEEE 802.11ad devices with zero overhead and no changes to the operation of the standard Zero Overhead Device Tracking

19 December 14, 2017  Goal: track movement and rotation of IEEE 802.11ad devices with zero overhead and no changes to the operation of the standard  Challenges:  Designing multi-lobe beam patterns that allow for misalignment tracking Zero Overhead Device Tracking  Detecting the phase shift among non-equalized preamble halves

19 December 14, 2017  Goal: track movement and rotation of IEEE 802.11ad devices with zero overhead and no changes to the operation of the standard  Challenges:  Designing multi-lobe beam patterns that allow for misalignment tracking Zero Overhead Device Tracking  Detecting the phase shift among non-equalized preamble halves  Contributions and results:  Accurate per-packet movement and rotation tracking of a path  Mechanism is fully backward compatible with IEEE 802.11ad devices 1. No change to the operation nor frame format of IEEE 802.11ad 2. Mechanism works even when communicating with legacy nodes