Developing of MIMO Street Models

Background

A MIMO system employs multiple transmit and multiple receive antennas resulting in better system performance and larger capacity over traditional SISO channels. Furthermore, multi-element antennas can be placed on car roofs. This fact makes MIMO channels very attractive for vehicle-to-vehicle communications (V2V). In V2V, both the transmitter and the receiver are moving. The communication between vehicles can be considered as a kind of Mobile-to-Mobile (M2M) communication. M2M communications are expected to play an important role in various fields including ad hoc networks and intelligent transportation systems. In such systems, extremely reliable links are required. To cope with problems faced during the development and performance investigation of future mobile-to-mobile multiple-input multiple-output (MIMO) communication systems, a solid knowledge of the underlying multipath fading channel characteristics is essential.

M2M radio channels differ from classical cellular radio links in terms of Doppler spectrum characteristics. Therefore, new channel models for M2M communications are needed. Geometrical channel models, such as the one-ring model, the two-ring model, and the elliptical model constitute an important category of channel models. Unfortunately, the listed geometrical channel model cannot be used to describe accurately the propagation conditions of M2M channels along streets. Therefore, a new fourth major class of geometrical-based channel models, called the street model, will be developed.

Planned Research

This research work focuses on the derivation, analysis, and simulation of a street model for car-to-car MIMO channels. The geometrical street model for MIMO channels is shown in Figure 1. The geometrical street model takes into account that in typical M2M communication scenarios along streets, the scatterers are randomly clustered along parallel lines. Given the random distribution of the clusters of scatterers, the exact relationship between the angle of arrival (AoA) and the angle of departure (AoD) shall be established as a function of the parameters describing the geometrical street model. Starting from the developed geometrical street model, the corresponding stochastic reference and simulation models shall be derived by applying the generalised sum-of-sinusoids principle. The statistical properties of both the reference and the simulation model shall be studied with emphasis on the amplitude distribution and the correlation properties, which includes the temporal, spatial, and frequency correlation functions.

It is also planned to study the characteristic quantities giving insight into the dynamic behaviour of the street model, such as the Doppler spread, LCR, and ADF. Moreover, the channel capacity will be studied in detail. Exact solutions for the mean capacity, PDF, LCR, and ADF of the capacity of the street model will be derived. The new street model will be compared to known car-to-car channel models developed by using ray-tracing techniques.

Figure 1. Geometric street scattering model for MIMO channel.

Collaboration

Within the frame of this project, we are co-operating with:

UniK - University Graduate Center, Oslo, Norway
École Supérieure des Communicationes de Tunis (SUP’COM), Tunis, Tunisia

PhD Student: The PhD student working on this topic is Mr. Ali Chelli.

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