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The use of multiple antennas at both the transmitter and receiver is well motivated by the substantial performance gains that can be realized, both in terms of an increase in achievable data rate and a decrease in error rate. The achievable data rate is characterized by the mutual information of the channel. In case of frequency selective multiple input multiple output (MIMO) channels, expressions...
In this paper, we propose a QoS control mechanism that estimates the congestion of wireless channels in the wireless LAN and evaluates the voice packet drop ratio based on the estimated congestion status. The mechanism adjusts the voice packet transmission rate according to the evaluated packet loss ratio, and thereby resolves the congestion situation. In this way, the mechanism can keep users' quality...
For the mobile radio channel parameter estimation, the Space-Alternating Generalized Expectation-maximization (SAGE) algorithm is a popular scheme to estimate the individual path parameters, i.e., the relative delay, incidence azimuth, Doppler frequency, and complex amplitude of impinging waves. Because of the constraint of bandwidth of channel sounding signal and the limitation of the number of antennas,...
In this paper, we explore the idea of using traffic forecasting to improve the delay performance of a schedule-based medium access control protocol. Schedule-based channel access has been shown to utilize network and energy resources efficiently but is often hindered by the extra delay that scheduling introduces. We explore the use of traffic forecasting to anticipate transmission schedules instead...
This paper is about a few implementation aspects of a clustering algorithm for grouping parameters of the channel's multipath components. Issues as initialization and the computation of distance between multipath components are discussed. Special attention is given to the cluster validation problem dealing with the number of clusters' estimation. In this context, some validation measures and fusion...
The Wireless Body Area Networks technology is a promising candidate for various potential applications in the domains of health, monitoring, sport, multimedia, entertainment, data transfer, etc. The optimization of WBANs at the system level requires an accurate knowledge of the propagation channel which plays a key role on the design of the PHY, MAC and Network layers. The explosive combinatory due...
Body Area Networks connect low-power wireless bio-sensors, which are placed in close proximity of the human body. In order to reduce energy consumption, a promising solution is to use the ultra-wideband (UWB) technology in a multiple-sensor multiple-antenna (MS-MIMO) system. This paper deals with a new empirical space-time channel model of the ground reflection.
This paper presents the results of an investigation into the effect of using co-axial cables in ultra-wideband off-body radio channel characterisation and performance evaluation for wearable antennas. Experiments were carefully designed to faithfully compare the use of a co-axial feed cable for a wearable antenna versus an optic fibre feed, and thus report on any errors introduced into the measurements...
In this paper, we compare the two most common types of statistical models for V2V channels: the tapped-delay line, and the geometry-based stochastic model. We first provide a description of each model type. Model adaptations and options are described, as is model flexibility, and ability to replicate statistics that agree with measurements. We quantify each model's complexity, and show that the modified...
Time Based (TB) localization in terrestrial mobile radio as an augmentation for global navigation satellite systems has recently gained plenty of interests. As an essential tool to develop suitable algorithms for positioning applications in mobile radios, channel models for wireless transmissions have growing significance. Currently there is a lack of investigations on comparing the propagation characteristics...
Complex sensor network applications include multiple services such as collection, dissemination, time synchronization, and failure detection protocols. Many of these protocols require local state maintenance through periodic broadcasts which leads to high control overhead. Recent attempts to consolidate these broadcasts focus on piggybacking information into existing services but such tight coupling...
Large scale parameters (LSP) mainly describe the distribution of the transmitted power over different dimensions of the channel. The required statistic is obtained from MIMO channel measurements with an appropriate post processing procedure. In this contribution, we perform the characterization of large scale parameters within an urban macro cell scenario. We focus on investigating the influence of...
We report on the results of an air-to-ground radio channel measurement campaign that we performed at 5120 MHz with 20 MHz bandwidth (within the extension band currently allocated to the microwave landing system). In particular, the measurements addressed the channel corresponding to transmission between a passenger aircraft and a fixed terrestrial ground station, e.g. for telemetry purposes. Time-variant...
This paper compares radio channel measurements and ray tracing simulations in an outdoor environment. A model for diffuse scattering is implemented in a ay tracing tool. Simulations results show that this implementation is important to improve both pathloss and crosspolarization accuracy prediction. To improve delay spread prediction it is necessary to increase the maximum number of simulated interactions...
The COST 2100 MIMO channel model is the latest evolution of the geometry-based stochastic channel models developed by the COST actions. This paper provides a full parameterization of the COST 2100 channel model in four indoor scenarios based on channel measurements conducted in two different buildings. In addition to the parameter values, the meaning and extraction method of each parameter are explained.
Measuring the land-mobile satellite channel by a channel sounder campaign involves in general massive costs. Using signals from GNSS instead could be considered as an opportunity providing large bandwidth, transmitter at accurately known positions and time synchronisation. The major drawback is the low received signal power such that features of the propagation channel might disappear in the noise...
A methodology to construct radio source distribution map using antenna arrays distributed in indoor environments is proposed. The map is constructed based on the image method of field prediction and shows locations of the primary (original) and secondary (mirrored) sources with their intensity. The map provides in-depth description of propagation mechanisms including specular reflection and diffused...
This work presents theoretical and experimental analysis of radio signals propagation in LOS and NLOS indoor propagation conditions. Specifically, propagation conditions in straight corridor and adjacent rooms are analysed. A statistical multi-parametric approach that was previously used in urban propagation conditions is adapted to the modelling of indoor communication channels. The model of the...
The development of MIMO over-the-air (OTA) test methodology is an ongoing activity in 3GPP RAN4, CTIA and EU COST Action 2100. In this paper, the focus is on the anechoic chamber approach, which uses a uniform circular array of probe antennas to replicate directional channels for the device-under-test at the array center. In particular, we study in simulation the complexity requirements of implementing...
Radio channel measurements in the 2-6 GHz frequency band were performed in two different outdoor environments including the dense urban environment in Manchester and the rural/semi-rural environment of Ipswich. The data were analysed to obtain rms delay spreads for sectored antennas as well as to estimate channel functions for time domain and frequency domain channel simulators of the IEEE802.16-d...
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