Investigation of MIMO Channel Characteristics in a Two-Section Tunnel at 1.4725 GHz

This paper presents results from a wide band single-input–single-output (SISO) and 16 × 16 virtual multiple-input–multiple-output (MIMO) measurement campaign at a center frequency of 1.4725 GHz in a 100-meter long tunnel laboratory which is terminated by a vertical wall with a metallic door. The path loss, root-mean-square delay spread (RMS-DS) characteristics, and power delay profiles (PDPs) are described. In addition, we provide results for the MIMO channel amplitude matrix, which offers a new perspective in understanding MIMO characteristics in tunnel scenarios. Our measurement results are analyzed and compared to ray tracing simulations. The relationships among the angle spread, channel matrix singular values, and MIMO capacity at various link distances are illustrated, and these provide insights into MIMO system deployment

The characterisation and modelling of the wireless propagation channel in small cells scenarios

“A thesis submitted to the University of Bedfordshire, in partial fulfilment of the requirements for the degree of Doctor of Philosophy”.The rapid growth in wireless data traffic in recent years has placed a great strain on the wireless spectrum and the capacity of current wireless networks. In addition, the makeup of the typical wireless propagation environment is rapidly changing as a greater percentage of data traffic moves indoors, where the coverage of radio signals is poor. This dual fronted assault on coverage and capacity has meant that the tradition cellular model is no longer sustainable, as the gains from constructing new macrocells falls short of the increasing cost. The key emerging concept that can solve the aforementioned challenges is smaller base stations such as micro-, pico- and femto-cells collectively known as small cells. However with this solution come new challenges: while small cells are efficient at improving the indoor coverage and capacity; they compound the lack of spectrum even more and cause high levels of interference. Current channel models are not suited to characterise this interference as the small cells propagation environment is vast different. The result is that overall efficiency of the networks suffers. This thesis presents an investigation into the characteristics of the wireless propagation channel in small cell environments, including measurement, analysis, modelling, validation and extraction of channel data. Two comprehensive data collection campaigns were carried out, one of them employed a RUSK channel sounder and featured dual-polarised MIMO antennas. From the first dataset an empirical path loss model, adapted to typical indoor and outdoor scenarios found in small cell environments, was constructed using regression analysis and was validated using the second dataset. The model shows good accuracy for small cell environments and can be implemented in system level simulations quickly without much requirements

Cluster Angular Spreads in a MIMO Indoor Propagation Environment

Abstract — An important parameter of MIMO channel models is the cluster root-mean-square (rms) directional spread. In this paper we determine this parameter in the angle-of-arrival/angleof-departure (AoA/AoD) domain based on comprehensive indoor MIMO measurements at 5.2 GHz in a cluttered office environment. This is done in a four-step procedure: (i) the SAGE algorithm is used to extract propagation paths, (ii) clusters of estimated paths in the double-azimuth domain are defined, (iii) the estimated propagation paths are allocated to the clusters, (iv) the cluster spreads are estimated based solely on propagation paths within the clusters. We found that the spreads are different when seen from transmitter or receiver due to different propagation conditions resulting in AoD rms cluster spreads lying in the range from 2 to 9 degrees and AoA rms cluster spreads in the range from 2 to 7 degrees. I