Efficient 2-D ray-tracing method for narrow and wideband channel characterisation in microcellular configurations

Abstract

Channel characterization is an essential step to the development of outdoor or indoor wireless networks. Indeed, for multimedia applications, new radio mobile systems must accurately take into account channel behavior. In this paper, we propose an efficient 2D ray-tracing method to characterize the narrow and wide-band radio channels for a very large number of receivers in micro-cellular configurations. It is based on a quick pre-calculation of an exact 2D visibility graph. The proposed method follows an ITU recommendation, which advocates, for wide-band characterization, only considering the paths included in a 18 dB dynamic range of power impulse response. Contrary to the classical approach, which consists in thresholding the complete impulse response in a post-treatment, our method only computes the significant paths. The interest of the proposed method resides in its significant computation time reduction factor, in comparison with the classical approach and this without any significant loss in accuracy. Received power and wide-band parameter maps are computed for about 40,000 receivers, in a dense urban environment, and are provided with an approximate reduction factor of 4 and 80% of null estimation error in comparison to a classical approach.

Field prediction in urban environment using radar approach

“…The determination of the different sectors is performed by considering the width of the incident and reflected wavefronts for a specular reflection [3,8]. It has to be noticed that the algorithm dedicated to the determination of the façade sectors is written in 3D: it is valid for any incidence direction and takes the limited height of the buildings into account.…”

“…It implies that a part of the field reflected by the façade F 1 is submitted to a second reflection by the façade F 2 . The part of the façade F 1 contributing to the single reflection corresponds to B 1 B 2 0 where B 2 0 is the projection of B 2 on F 1 along the reflected ray according to ray-tracing method [3]. Finally, the RCS of the single reflection on this façade area is calculated using formulas (2)…”

“…As for the single reflection, the width of the reflected wavefront is taken into account to find the contributing façade sectors [3,8]. Our approach, to efficiently account for this double reflection mechanism, consists of combining the geometrical optics with an analytical RCS calculation.…”

“…In the same way, the simulated area is restricted to reduce the number of paths; as a result, the contribution of far-field buildings outside the simulated area is neglected. Efforts have been done to permit a fully three-dimensional approach by reducing the number of rays to consider [1][2][3]. By following the same objective of computation time reduction, we propose in this article a compact representation of the 3D scattering properties of far-field buildings.…”

“…Lyashenko et al investigated an alternate tuning scheme: application of an external stress on yttrium iron garnet (YIG) films. The compressive or tensile strain resulted in an anisotropy field in YIG, leading to frequency tuning of magnetostatic waves by 625% of the central frequency of 2-3 GHz [2,3].…”