Wiener-System Subspace Identification for Mobile Wireless mm-Wave Networks

• Published in: IEEE transactions on vehicular technology 2007-07, Vol.56 (4), p.1935-1948
• Main Authors: Galvao, Roberto Kawakami Harrop, Hadjiloucas, Sillas, Izhac, Abdurrahman, Becerra, Victor M., Bowen, John W.
• Format: Article
• Language: English
• Subjects: Algorithms; Applied sciences; Atmospheric modeling; Communication systems; communication-system nonlinearities; communication-system planning; Computer simulation; Detection, estimation, filtering, equalization, prediction; Diffraction; Electric fields; Exact sciences and technology; Fading; Information, signal and communications theory; Large-scale systems; Mathematical models; Nonlinear dynamical systems; Organization and planning of networks (techniques and equipments); Radiocommunications; Receivers; Reflection; Sensitivity analysis; Signal and communications theory; Signal, noise; Solid modeling; Studies; Submillimeter wave communication; Subspaces; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Transmitters. Receivers; Urban areas; Wireless communication
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2007.897250

We discuss the feasibility of wireless terahertz communications links deployed in a metropolitan area and model the large-scale fading of such channels. The model takes into account reception through direct line of sight, ground and wall reflection, as well as diffraction around a corner. The movement of the receiver is modeled by an autonomous dynamic linear system in state space, whereas the geometric relations involved in the attenuation and multipath propagation of the electric field are described by a static nonlinear mapping. A subspace algorithm in conjunction with polynomial regression is used to identify a single-output Wiener model from time-domain measurements of the field intensity when the receiver motion is simulated using a constant angular speed and an exponentially decaying radius. The identification procedure is validated by using the model to perform q -step ahead predictions. The sensitivity of the algorithm to small-scale fading, detector noise, and atmospheric changes are discussed. The performance of the algorithm is tested in the diffraction zone assuming a range of emitter frequencies (2, 38, 60, 100, 140, and 400 GHz). Extensions of the simulation results to situations where a more complicated trajectory describes the motion of the receiver are also implemented, providing information on the performance of the algorithm under a worst case scenario. Finally, a sensitivity analysis to model parameters for the identified Wiener system is proposed.