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Real-Time Geometry-Based Wireless Channel Emulation

Hofer, Markus; Xu, Zhinan; Vlastaras, Dimitrios LU ; Schrenk, Bernhard; Loschenbrand, David; Tufvesson, Fredrik LU and Zemen, Thomas (2018) In IEEE Transactions on Vehicular Technology
Abstract

Connected autonomous vehicles and industry 4.0 productions scenarios require ultra-reliable low-latency communication links. The varying positions of transmitter, reflecting objects and receiver cause a non-stationary time- and frequency-selective fading process. In this paper, we present the necessary hardware architecture and signal processing algorithms for a real-time geometry-based channel emulator, that is needed for testing of wireless control systems. We partition the non-stationary fading process into a sequence of local stationarity regions and model the channel impulse response as sum of propagation paths with time-varying attenuation, delay and Doppler shift. We implement a subspace projection of the propagation path... (More)

Connected autonomous vehicles and industry 4.0 productions scenarios require ultra-reliable low-latency communication links. The varying positions of transmitter, reflecting objects and receiver cause a non-stationary time- and frequency-selective fading process. In this paper, we present the necessary hardware architecture and signal processing algorithms for a real-time geometry-based channel emulator, that is needed for testing of wireless control systems. We partition the non-stationary fading process into a sequence of local stationarity regions and model the channel impulse response as sum of propagation paths with time-varying attenuation, delay and Doppler shift. We implement a subspace projection of the propagation path parameters, to compress the time-variant channel impulse response. This enables a low data-rate link from the host computer, which computes the geometry-based propagation paths, to the software defined radio (SDR) unit, that implements the convolution on a field programmable gate array (FPGA). With our new architecture, the complexity of the FPGA implementation becomes independent of the number of propagation paths. Our channel emulator can be parametrized by all known channel models. Without loss of generality we use a parameterization by a geometry-based stochastic channel model (GSCM), due to its non-stationary nature. We provide channel impulse response measurements of the channel emulator, using the RUSK Lund channel sounder for a vehicular scenario with 617 propagation paths. A comparison of the time-variant power delay proflie (PDP) and Doppler spectral density (DSD) of simulated and emulated channel impulse response showed a close match with an error smaller than -35 dB. The results demonstrate that our channel emulator is able to accurately emulate non-stationary fading channels with continuously changing path delays and Doppler shifts.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
IEEE Transactions on Vehicular Technology
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85058870611
ISSN
0018-9545
DOI
10.1109/TVT.2018.2888914
language
English
LU publication?
yes
id
c9e2bc2a-6edc-42c2-a548-b735c010d6d2
date added to LUP
2019-01-10 09:52:04
date last changed
2019-02-20 11:42:24
@article{c9e2bc2a-6edc-42c2-a548-b735c010d6d2,
  abstract     = {<p>Connected autonomous vehicles and industry 4.0 productions scenarios require ultra-reliable low-latency communication links. The varying positions of transmitter, reflecting objects and receiver cause a non-stationary time- and frequency-selective fading process. In this paper, we present the necessary hardware architecture and signal processing algorithms for a real-time geometry-based channel emulator, that is needed for testing of wireless control systems. We partition the non-stationary fading process into a sequence of local stationarity regions and model the channel impulse response as sum of propagation paths with time-varying attenuation, delay and Doppler shift. We implement a subspace projection of the propagation path parameters, to compress the time-variant channel impulse response. This enables a low data-rate link from the host computer, which computes the geometry-based propagation paths, to the software defined radio (SDR) unit, that implements the convolution on a field programmable gate array (FPGA). With our new architecture, the complexity of the FPGA implementation becomes independent of the number of propagation paths. Our channel emulator can be parametrized by all known channel models. Without loss of generality we use a parameterization by a geometry-based stochastic channel model (GSCM), due to its non-stationary nature. We provide channel impulse response measurements of the channel emulator, using the RUSK Lund channel sounder for a vehicular scenario with 617 propagation paths. A comparison of the time-variant power delay proflie (PDP) and Doppler spectral density (DSD) of simulated and emulated channel impulse response showed a close match with an error smaller than -35 dB. The results demonstrate that our channel emulator is able to accurately emulate non-stationary fading channels with continuously changing path delays and Doppler shifts.</p>},
  author       = {Hofer, Markus and Xu, Zhinan and Vlastaras, Dimitrios and Schrenk, Bernhard and Loschenbrand, David and Tufvesson, Fredrik and Zemen, Thomas},
  issn         = {0018-9545},
  language     = {eng},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Transactions on Vehicular Technology},
  title        = {Real-Time Geometry-Based Wireless Channel Emulation},
  url          = {http://dx.doi.org/10.1109/TVT.2018.2888914},
  year         = {2018},
}