From Multi-Keyholes to Measure of Correlation and Power Imbalance in MIMO Channels: Outage Capacity Analysis

An information-theoretic analysis of a multi-keyhole channel, which includes a number of statistically independent keyholes with possibly different correlation matrices, is given. When the number of keyholes or/and the number of Tx/Rx antennas is large, there is an equivalent Rayleigh-fading channel such that the outage capacities of both channels are asymptotically equal. In the case of a large number of antennas and for a broad class of fading distributions, the instantaneous capacity is shown to be asymptotically Gaussian in distribution, and compact, closed-form expressions for the mean and variance are given. Motivated by the asymptotic analysis, a simple, full-ordering scalar measure of spatial correlation and power imbalance in MIMO channels is introduced, which quantifies the negative impact of these two factors on the outage capacity in a simple and well-tractable way. It does not require the eigenvalue decomposition, and has the full-ordering property. The size-asymptotic results are used to prove Telatar's conjecture for semi-correlated multi-keyhole and Rayleigh channels. Since the keyhole channel model approximates well the relay channel in the amplify-and-forward mode in certain scenarios, these results also apply to the latterComment: accepted by IEEE IT Trans., 201

The Effects of Increasing Antenna Arrays for MIMO in Mine Tunnels

The aim of this paper is to prove theoretically by using waveguide and geometrical optical models that increasing MIMO array elements at the transmitter and receiver will have a limit on capacity where the equivalent spatial subchannels can be limited by the number of allowable modes

A Multi-mode Waveguide Tunnel Channel Model for High-Speed Train Wireless Communication Systems

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The recent development of high-speed trains (HSTs) introduces new challenges to wireless communication systems for HSTs. For demonstrating the feasibility of these systems, accurate channel models which can mimic key characteristics of HST wireless channels are essential. In this paper, we focus on HST channel models for the tunnel scenario, which is different from other HST channel environments, such as rural area and viaducts. Considering unique characteristics of tunnel channel environments, we extend the existing multi-mode waveguide tunnel channel model to be time dependent, obtain the channel impulse responses and then further investigate the certain key tunnel channel characteristics such as temporal autocorrelation function (ACF) and power spectrum density (PSD). The impact of time on ACFs and PSDs, and the impact of frequency on the received power are revealed via numerical results

Analyse des caractéristiques du canal MIMO dans mine souterraine

Short-range wireless communications technology has been embraced by the underground mining community in the last few years as a critical part of their method for enhancing the security and productiveness of their operations. In this work, we will demonstrate how the deployment of modern wireless communication systems, primarily based on MIMO antenna array technology will be affected in unique environments like underground gold mines. This work first explores the relation between the number of modes in a lossy waveguide environment and a Multiple-Input Multiple-Output antenna array size. Besides, knowing that beamforming for Massive MIMO is not suitable for deployment in underground mines. We demonstrated that applying beamforming in waveguide-like structures can enhance the performance and that by choosing the appropriate precoding techniques at the transmitter and receiver. Then, in order to achieve more reliability to the MIMO channel, a theoretical study obtained in mine comparing the capacity and power for different antenna configurations. Finally, we estimated the number of propagating modes in a rectangular cross-sectional mine environment and express it as a closed-form function of excitation frequency and waveguide cross-sectional dimensions and length. The presented formulas can be used to estimate the number of modes in the given shape quickly. By applying those previous methods before deploying the wireless communication system in mine, engineers can save time and cost. Besides, they can achieve the highest capacity within the implemented environment by building a wireless channel which is suitable for their desired frequency band

Electromagnetic Wave Propagation Modeling for Finding Antenna Specifications and Positions in Tunnels of Arbitrary Cross-Section

This chapter is organized as follows : Section II introduces the modal approach for guiding structures. It is based on a full-wave method, namely the Transmission Line Matrix (TLM) method. These methods has been hampered by their large computational time when compared to asymptotic methods when large size environments are considered. Thus, a suitable 2.5 D TLM implementation to reduce the computational time and to include lossy dielectric walls of tunnels is briefly presented [2]. The computation cost is reduced compared to typical solutions by using the concept of Surface Impedance Boundary Condition (SIBC). Section III is devoted to the description of a methodology for the determination of antenna field specifications and positioning in operational scenarios at high frequencies. Section IV presents the validation of this methodology for a simple canonical case. Lastly, section V describes the analysis and results for a real scenario representative of tunnel environments. Finally, discussions and conclusions are developed

Electromagnetic Dimensionality of Deterministic Multi-Polarization MIMO Systems

Multiple-Input Multiple-Output (MIMO) systems are viewed as the last available supply for the ever-growing demand on higher data rates in modern wireless communication systems. Smart exploitation of the traditional wireless resources (time-slots or bandwidth under the same transmit power level) has reached its saturation point. By making better use of the free space between the radio links, based on the multipath radio wave propagation, MIMO systems have shown significant capacity improvement with the same traditional wireless resources. In this multi-disciplinary research, we are exploring the link between the electromagnetic propagation and the information theory. Unlike the majority of recent research work, we model the propagation channel matrix between the transmit/receive elements in a deterministic manner under the Maxwellian framework. Having included the environment properties and the characteristics of the radiating elements, the deterministic approach provides a realistic assessment of the MIMO system performance in specific scenarios. The problem addressed in this research is the evaluation of the multi-antenna systems degrees of freedom (DOF) by employing all the available electromagnetic diversity resources (spatial, pattern and polarization). Based on a developed well-defined power independent dimensionality (PID) metric, we start by investigating the information-bearing potential of the collocated multi-polarization MIMO system. We study the hexapole system (exploiting both electric and magnetic fields in conveying independent information) and compare it to the tripole systems (exploiting the vectorial polarization diversity of one field only). We present numerical results for 3 deterministic scenarios: a canonical free-space (near and far field exact solution), a canonical perfect electric conductor (PEC) corridor using rigorous modal analysis, and a lossy-wall corridor using image ray tracing (IRT). Next, we provide deterministic results for the more interesting sampling problem of the electromagnetic vector fields: given a specific MIMO array size, what is the optimum number of packed multi-polarization antennas (i.e. multi-polarization 1D, 2D or 3D sampling) that yields the largest PID for a given environment and what is the estimate of this PID? Using a canonical case of multi-polarized arrays inside a multipath-rich PEC corridor, we show that the spatial frequency spectrum of the electromagnetic field governs the optimum PID of the site-specific scenario. The problem is analogous to the DOF determination of an essentially time-limited-band-limited 1D scalar function using the framework of the prolate spheroidal wave functions. We also present simulation results for the same sampling problem in a lossy-wall indoor environment using IRT