This paper presents a measurement-based evaluation of link budget gain from uplink transmit antenna selection in 3GPP LTE. In contrast to earlier studies, the results are based on channel measurements and realistic non-omnidirectional mobile terminal antennas. Further, in addition to the impact of fast selection based on small-scale fading power, also the gain from slow selection based on average signal power is evaluated. In the evaluated measurement cases, fast and slow fading based transmit antenna selection result in up to $3.7$ and $3.2$ dB average power gain, respectively, with respect to the fixed uplink transmit antenna case. This implies that with practical non-omnidirectional terminal antennas a major portion of the gain can be realized based on slow selection, hence justifying a simple open-loop transmit antenna selection scheme which is also applicable to FDD systems.

This paper presents a performance evaluation of 60 GHz high-speed radio systems under an application scenario related to a medical operation. The evaluation is based on the following specifications: IEEE 802.15.3c and IEEE 802.11ad, which have been designed to provide data rates of multi-Gbps at physical layer. First, by using measured power delay profiles (PDPs) in hospital environments, both inter-symbol-interference (ISI) and channel capacity are calculated. Then, system simulations are carried out in order to show achievable throughputs. The results reveal that OFDM systems provide the required throughput for the application scenario in all the measured PDPs. On the other hand, the single carrier (SC) systems without any equalization are limited to 85 % of the measured PDPs where the required throughput is achieved. Also, it is shown that the calculated channel capacity for each measured PDP reveals the similar trend with the available throughputs obtained from the system simulations.

The incorporation of new services in handheld devices, such as the Digital Video Broadcast-Handheld (DVB-H) operating at the lower ultrahigh-frequency (UHF) band poses a challenge for antenna designers. Wideband small antennas or electrically tunable narrowband small antennas are needed to fulfil the performance requirement. It is well known that below 900 MHz the operation of embedded mobile terminal antennas is based on utilizing the whole structure of the terminal as a radiator. However, even this way reaching the whole required impedance bandwidth of about 46% at about 0.61-GHz center frequency is possible only either with clamshell-type terminals used as thick dipoles by feeding them from the hinge or with “large tablet”-sized terminals. With the popular smartphone-sized terminals with a monoblock structure the available bandwidth with good total efficiency is clearly smaller. We study the options to implement antennas for smartphone-type mobiles for receiving digital TV broadcasts at about 0.47-0.75-GHz frequencies. The mainly studied technology is the nonresonant capacitive coupling element (CCE)-type antennas having one of the smallest achieved volume-to-bandwidth ratios. We show that for a fixed-frequency antenna with a volume of less than a few cubic centimeters the total efficiency will become rather low due to moderate matching level, but the requirement of the DVB-H standard for the realized gain can easily be met. Additionally, we show that by having switching between two bands, one can implement a dual-antenna configuration with small total volume and significant multiple-input-multiple-output (MIMO) gain. Furthermore, we study the very important effect of the user's hands on the antenna performance and find that the effect can range from some increase of the total efficiency due to improved matching to significant losses caused by the hands. Finally, we propose some possible ways ahead in solving this very challenging antenna design problem.

This letter presents radio channel measurements and modeling results for the feasibility study of 60 GHz high-speed radio systems in hospital environments. Two possible applications of those systems are considered: real-time video streaming for angiography and for ultrasonic inspection. Channel modeling was performed for the path loss and multipath characteristics of the propagation channel, i.e., the delay spreads. Results revealed generally lower path loss and delay spread values compared to regular indoor office and residential environments. The results indicate that the 60 GHz radio systems operating in hospital environments can provide better signal quality and wider coverage than those operated in regular indoor environments, though increased interference with neighboring cells might be an unfortunate consequence.

This paper presents a comprehensive simulation study on the performance of broadband coupling-element-based multiantenna structures on a mobile terminal at the 2000 MHz Universal Mobile Telecommunications System (UMTS) frequency band with varying two significant hand effects; vertical position of hand along terminal chassis, and distance between hand palm and terminal chassis. The results reveal that there exists an MEG imbalance between antenna elements due to hand effects and it is shown that an MEG imbalance of 3.7 dB lead to a reduction of 1.9 dB in diversity gain at 99% reliability level using maximal ratio combining (MRC) technique. For a two-element antenna configuration, the impact of MEG imbalance on diversity gain is more significant when only one antenna element is in close proximity to the hand, compared to when both antenna elements are in the presence of the hand. It is also shown that a broadband multiantenna structure with elements vertically oriented along the edges of a small 100 mm x 40 mm mobile terminal chassis achieves better performance in port-to-port isolation, MEG imbalance and diversity gain compared to other studied multiantenna configurations when the user's hand is present.

There has been extensive research about single link multiple-input multiple-output (MIMO) channels, both simulated and measured, but only few studies have targeted multilink analysis with measured channel data. Hence, in this paper, we analyze the influence of spatial separation of user terminals and the human shadowing effect on the MIMO capacity and to the signal to interference ratio (SIR) in a time-variant dual-link scenario. The paper analyses the dual-link channel capacity based on simulations as well as measurements conducted using dynamic dual-link dual-polarized wideband MIMO channel sounder in an indoor office environment, and compare the results to the singlelink capacity. Here the analysis is restricted to 4 x 4 MIMO links. The following conclusions have been obtained from the analyses: 1) Compared to the single link case, the dual-link channel capacity is more affected by the SIR than the spatial separation of the users. 2) The human shadowing introduced variations of SIR up to ±10 dB, causing large fluctuations in the dual-link capacity.

This report describes results from 60 GHz channel measurements and modelling in a shielded room. Final goal of this work is to investigate potential and feasibility of 60 GHz radios for very-high-data-rate short-range communications in medical applications. The measurement in a shielded room is meaningful for studying propagation characteristics in medical applications, since real surgery rooms are typically shielded. One particular usage scenario, i.e., real-time video streaming for ultrasonic imaging, was considered, where the antenna settings were adjusted to the usage scenario accordingly. Link budget and delay domain multipath characteristics were analyzed and modelled. Finally, model parameters that fit the measured power delay profiles were given.

In this paper radio wave scattering processes in an indoor hall environment are reported by analyzing double-directional multiple-input-multiple-output (MIMO) channel sounding data at 5.3 GHz. The pathways and scattering processes of the dominant propagation phenomena were identified using a measurement-based ray tracer (MBRT) software. It is shown that the dominant propagation phenomena included a line-of-sight (LOS) or obstructed LOS component, single, double, and triple bounce scattering processes from walls and ground. The proportion of power carried by each identified pathway was studied. The number of active pathways varied between 3 and 8, which indicates that the multipath environment changes significantly during the measurement route.

Measurements of car-to-car (C2C) radio channels with 60 MHz bandwidth at 5.3 GHz have been performed in Helsinki, Finland. We focused on 30x30 multiple-input multiple- output (MIMO) measurements, conducted in four environments (urban, sub-urban, campus and highway), under quasi-realistic traffic conditions. As first results, we present in this paper the delay spread statistics for each investigated environment. The largest values of root-mean-square (RMS) delay spread, roughly 2 mus, were obtained in the urban environment. The narrowband channel fading statistics have also been derived using composite distributions, in order to assess the global fading statistics.

In this paper, the link budget of the multiband UWB channel is studied based on empirical analysis of path loss and shadow fading by dividing the frequency range into multiple sub- bands with 500 MHz bandwidth. The work is based on ultra- wide band (UWB) propagation measurements performed in two indoor environments of a hall and a corridor in the frequency range of 3-10 GHz. It is found that in the multiband channels, the path loss exponent is independent on frequency, and the mean path loss can be modelled as a function of frequency. Shadowing (in dB) fits well with normal distribution, and the standard deviation (STD) of shadowing shows a tendency of increasing with frequency. Furthermore, the shadow fading margin with 90% link success probability is found to bee fairly low (less than 4 dB) the multiband channels. The presented results can be used for design of UWB radio systems.

The performance analysis for realistic 5 GHz multi-element terminal antennas in peer-to-peer communications is presented in three typical indoor usage environments. Double directional experimental plane-wave based method (EPWBM) is used to combine the simulated 3-D radiation patterns of the antennas with large amount of experimental double directional channel data to get MIMO channel matrices that include the effect of the transmitter and the receiver antennas. Mutual information values of different antenna configurations in the studied environments are used in the performance evaluation. The performance of the antenna configurations with good angular coverage is noticed to be clearly better especially at high or average reliability levels than that of the antenna configuration with limited angular range. Generally, the performance of MIMO antenna systems in peer-to-peer scenarios is noticed to have larger fluctuation than in traditional base station scenarios.

An experimental plane-wave-based method (EPWBM) is extended to use measurement based double-directional channel models in the evaluation of the antennas at 5 GHz frequency range. The method enables a statistical antenna evaluation without performing long routes of radio channel sounder measurements to be carried out separately for the testing of each antenna systems under test. The method enables more comprehensive antenna evaluation in a significantly shorter period of time compared to direct measurements. For validation purposes, the results obtained with the EPWBM are compared with the results of direct radio channel measurements. The method is shown to be sufficiently accurate for comparing the performance of different antenna configurations.

In this paper, the radiation and resonance characteristics of open and closed position clamshell-type phone structures are studied at wide frequency range (from 0.6 GHz to 3 GHz) with help of coupling elements. In the closed position of the phone, the lambda/2 resonance of the chassis located close to the operating band of E-GSM900 system shows to be problematic due to low bandwidth potential and a radiation efficiency minimum. To improve the closed position performance of the antenna structure, a novel frequency tunable matching circuitry is proposed and studied with simulations. The results of this paper provide useful and novel information for the designers of antennas for clamshell-type phones. The findings of this paper can be also applied with traditional self-resonant antennas.

In this paper, based on indoor ultra-wide band (UWB) propagation channel measurements for both LOS and NLOS scenarios, the frequency dependency of propagation in the 3-10 GHz UWB range is investigated by examining the power delay profile, rms delay spread, path loss and shadowing as functions of frequency. Moreover, the bandwidth dependency of channel parameters is also investigated for gaining more understanding of the general channel properties

This paper presents a comparison between a correlation-based and a ray-based MIMO (multi-input multi-output) model. The correlation-based model has been presented in the literature under the European IST-METRA project. The ray-based model has been elaborated for the 3GPP standard group under the acronym of SCM. Using the input parameters of the 3GPP SCM model specification as a reference, link level simulations results generated from the two MIMO channel models are being compared by examining the channel coefficients and BLER (block error rate) produced by the models. When comparing the simulation results, it was found that the differences between the models are negligible. This implies that either one of the models can be used to generate channel coefficient realizations

Multiple scattering propagation channel is a physically motivated generic model whose special cases include Rayleigh, Rice, double-Rayleigh and "leaky keyhole" channels. Estimation of the parameters of its amplitude distribution is still largely an unexplored problem. In this paper, several novel estimators based on the empirical characteristic (ECF) function are derived. The mathematical form of the considered signal model makes the ECF approach ideally suited for the estimation problem at hand, whereas the maximum-likelihood (ME) estimator is analytically and computationally intractable. Furthermore, it can be easily extended to other similar signal models. By simulations it is shown that the derived ECF estimators have at least as small mean square error as the previously proposed moment-based approaches

The development of future wireless communication systems requires modeling of the radio propagation environment. These models need the estimation of the model parameters from channel sounding measurements. In this paper, we build a state-space model, and estimate the propagation parameters with the Extended Kalman Filter in order to capture the dynamics of the channel parameters in time. The model also includes the effect of distributed diffuse scattering in radio channels. The issue of varying state variable dimension, i.e., the number of propagation paths to track, is investigated. For this purpose, we rely also on maximum likelihood based estimation techniques. The proposed algorithm is investigated using both simulated and measured data.

In mobile radio propagation, the variation in the local mean power is called shadow fading (or slow fading). It has been observed experimentally that the distribution of shadow fading is approximately lognormal over a wide range of propagation environments, carrier frequencies, and receiver-transmitter distances, although the exact reason for this remains somewhat unclear. In this paper we model the received signal as a superposition of plane waves with random powers. It is shown that if the sum of the plane wave powers satisfy central limit theorem, the received signal will have approximately lognormal distribution. The result offers a novel explanation for the lognormality of shadow fading

We consider Rician fading multiple-input multiple-output (MIMO) channels where the transmitted signal has complex Gaussian distribution, iid across the transmit antennas. Based on expected values of elementary symmetric functions of complex noncentral Wishart matrices, we derive an upper bound on the average (ergodic) mutual information for arbitrary SNR, arbitrary rank of the deterministic line-of-sight matrix, and arbitrary number of transmit/receive antennas. The Rayleigh fading signal component is allowed to have spatial correlation at one end of the link. Upper bounds for the cases of rank-1 line-of-sight component and pure Rayleigh fading emerge as special instances of the general result

We consider mutual information of multiple-input multiple-output (MIMO) wireless channels with complex isotropic Gaussian input in the case where the receiver has perfect channel, knowledge. For arbitrary fading statistics, a mutual information lower bound is decomposed in a sum of three terms involving: a) average SNR; b) channel fading; and c) a term characterizing the "effective rank", or eigenvalue dispersion, of the channel matrix. The decomposition suggests that spatial multiplexing efficiency of a MIMO channel can be characterized by the so-called ellipticity statistic. Distribution functions, means and variances of the random terms in the decomposition for the case of Rayleigh fading are also derived

We consider multiple-input multiple-output (MIMO) communication systems where the transmitted vector has a zero-mean complex Gaussian distribution, independently and identically distributed across the transmit antennas. For arbitrary fading statistics, we decompose a high-SNR approximation of the mutual information as a sum of three terms involving: (1) average SNR; (ii) SNR fading; and (iii) a term characterizing the "effective rank", or eigenvalue dispersion, of the channel matrix. For further insight, we derive the probability densities of the latter two terms under frequency-flat Rayleigh iid fading, and show that the component of mutual information due to SNR fading is asymptotically Gaussian (in the number of antennas) with variance depending only on the ratio of the number of transmit and receive antenna elements.

It is expected that the enhanced-IMT2000 WCDMA cellular networks might open the possibility to use higher bandwidths than the 5 MHz specified in 3GPP. In this paper, the orthogonality factor (OF) for WCDMA downlink channel is characterized. The characterization is based on measurement results carried out at 2 GHz in microcellular environment. The impact of bandwidth on the OF is investigated for bandwidths of 5, 10, 20 and 30 MHz. The results of the investigations can be used in the assessment of downlink capacity of the WCDMA systems at different bandwidths.

Distinction between different propagation paths can be done by their delay, angle of arrival, angle of departure and Doppler-frequency. This also yields a possibility to have a measure that calculates a grade of (dis-) similarity between different multipath components. This work introduces the (dis-) similarity measure by introducing the concept of distance function that has been developed to provide a formal description for measuring distance between two points in a vector space. This measure provides some knowledge about multipath components clustering in different domains.

In this paper, the use of a combined signal processing technique of target discrimination for the step-frequency ground penetrating radar is investigated. To construct the radar range profile from the backscattered signal, a real part of the inverse discrete Fourier transform is multiplied by the pseudospectrum obtained from the same data via eigenvector method. The signatures of small underground objects can be subdivided in four categories designated conditionally as front wall; back wall; inclusion of high density; inclusion of low density. Experimental studies have shown that the technique is valid for both strong and weak scatterers. The approach can be extended to the discrimination of complex targets such as landmines by creating a set of templates.

Measured wideband direction-of-arrival data from urban macrocellular environment were clusterized. The clusterization was done by manual inspection. To understand the physical propagation channel, the source points of the extracted clusters were located to the local environment surrounding the mobile station. Some key parameters were calculated for each of the extracted clusters and for the residual power. By combining these parameters with the estimates of the cluster source points, assumptions on the propagation mechanisms of the clusters were drawn. According to the results the most significant sources are building structures above the average building height and corners of the buildings. This result is inline with previous studies in the urban propagation. Only a few significant clusters were found, in this study three clusters out of 14 extracted clusters contributed nearly 60% of the received power, while 19% of the power remained outside the clustering. Most of the clusters follow the Rician distribution with relatively high K-factor, while the residual power was Rayleigh distributed. There was only slight depolarization from the transmitted vertical polarization. One of the clusters was a clear exception with a negative XPR.

This paper presents the results achieved with a dual-polarized multiple-input multiple-output (MIMO) measurement system in the 2 GHz range. Results from continuous measurement routes were used in evaluating and comparing different MIMO antenna configurations. Different pattern and polarization diversity possibilities were studied using two methods: elements were selected from the antenna arrays used in measurements, and as another option, in the mobile station the incident waves were estimated and used in different dipole antenna arrays. The capacity limit seems to be higher in an indoor picocell than in an outdoor microcell environment. At the mobile station, directive elements result in 35% higher average capacities than those of the omnidirectional elements; however, the capacity of the directive elements also depends on the azimuth direction of arrival of the incident field. Dual-polarized antenna configurations have approximately 14% higher capacities than copolarized configurations. Increasing the number of mobile antenna elements increases the capacity in those environments where the angular spread of the incident field is large. Increasing the distance between elements at the fixed station increases the capacity - especially in microcells where signals arrive from specific directions.

The antenna system of ground penetrating radar is usually positioned in the vicinity of the ground surface to obtain sufficient spatial resolution for detecting small targets. Therefore, received signals are subject to errors caused by unwanted reflections and coupling. A near-field calibration procedure taking into account these effects as well as antenna dispersion is presented. For practical convenience, only a metal plane is used here as a calibration standard. Calibration data are measured for a set of distances between the antenna and metal plane. The reference reflections in all positions are computed using polynomial representation of the reflected signal. Then, error coefficients are obtained by a solution of a linear system of equations in the least squares sense. Experimental verification of the proposed calibration technique demonstrated efficient removal of artefacts caused by unwanted reflections. Moreover, peaks in the radar range profile become sharper after calibration if the antenna is dispersive. Consequently, the ground response in the form of an exponential term can be effectively subtracted from the received signal. This helps to reveal and discriminate shallow underground targets obscured by strong reflection of the ground surface. Experimental examples are given to illustrate the performance of the method.

Future mobile communication systems based on DS-CDMA require detailed characterization of the radio channel in the multipath delay domain (for short, the path domain). CDMA system designers need channel information in the form of RAKE fingers for successful receiver design. This work presents analysis of measurement results for obtaining active RAKE fingers and their characteristics.

Minimization of power loss in the tuning circuits of frequency-tunable small resonant antennas, such as microstrip patches, is studied. First, the frequency shift and the associated power loss in certain tuning circuits are theoretically calculated based on approximate circuit models of fairly narrowband resonant antennas. By investigating the ratio of frequency shift and loss, an optimal configuration for the tuning circuit can be determined. The theoretical results can be used to provide optimal starting values and design curves that facilitate the final design with a full-wave electromagnetic simulator. To support the theory, a design procedure is demonstrated with two example antenna structures, for which both simulated and measured results are presented.

For a low base station antenna located on one street, signals propagate into crossing and parallel streets by reflection and diffraction at corners of the buildings. In order to accurately predict the received signals, it is therefore necessary to properly model the diffraction coefficient at the building edges. This paper presents a new heuristic diffraction coefficient (NHDC), and compares ray tracing predictions to measurements of received power and rms delay spread. The NHDC has higher diffracted field strength in deep shadow than does the commonly used heuristic diffraction coefficient, and shows better agreement with measurements of both received power and delay spread.

We present a statistical analysis of wideband three-dimensional channel measurements at base station locations in an urban environment. Plots of the received energy over azimuth, elevation, and delay planes suggest that the incident waves group to clusters in most measured transmitter positions. A super-resolution algorithm (Unitary ESPRIT) allows one to resolve individual multipath components in such clusters and hence enables a detailed statistical analysis of the propagation properties. The origins of clusters-sometimes even individual multipath components-such as street apertures, large buildings, roof edges, or building corners can be localized on the city map. Street guided propagation dominates most of the scenarios (78%-97% of the total received power), while quasi-line-of-sight over-the-rooftop components are weak(3%-13% of the total received power). For this measurement campaign, in 90% of the cases, 75% of the total received power is concentrated in the two strongest clusters, but only 55% in the strongest one. Our analysis yields an exponential decay of power with 8.9 dB//spl mu/s, and a standard deviation of the log-normally distributed deviations from the exponential of 9.0 dB. The power of cross-polarized components is 8 dB below copolarized ones on average (vertical transmission).

In this paper, empirical channel models and parameters are derived from the wideband measured data at 5.3 GHz in outdoor mobile communications. The path loss exponents and intercepts are obtained by using the least square method. The mean excess delay and mean root-mean-square (rms) delay spread are within 29-102 ns and 22-88 ns, respectively. The correlation distances and bandwidths are within 1-11 /spl lambda/ and 1.2-11.5 MHz, respectively, when the envelope correlation coefficients equal 0.7 in line-of-sight cases. These correlation values depend strongly on the base station antenna heights. The window length for averaging out the fast fading components is about 1-2 m for microcells and picocells. The multipath number distributions follow both Poisson's and Gao's distributions, but Gao's distribution is better in the high probability region. Large excess delays up to 1.2 /spl mu/s and rms delay spread about 0.42 /spl mu/s are found in the urban rotation measurements, where the receiver is close to a large open square.

This paper considers passive intermodulation (PIM) effects occurring in passive RF devices like mobile communication antennas where two or more high-power signals can simultaneously be present in the transmitter-receiver path. Due to nonlinear properties of the passive parts, the unwanted PIM components with combination of carrier frequencies may fall within the receive band. In this paper, the main causes of PIM are briefly reviewed. A description of the measurement procedure for testing the PIM performance is presented. In addition, a comparison between the PIM properties of five commercially produced antennas is performed in the GSM 900 frequency region.

This paper presents the 360/spl deg/ azimuth angle channel modeling of wideband propagation in urban line-of-sight (LOS) microcellular environment of array antennas at the basestation and its experimental validations. First, the modeling includes rays from the whole 360/spl deg/ azimuth angles. Second, it verifies that the use of three-dimensional and two-dimensional methods in the forward and other reflection and diffraction propagation directions, respectively, is appropriate for the LOS propagation predictions. Third, it includes reflections from the curved surfaces of street corners and walls. Fourth, it extends existing expressions, making them applicable for array antennas at the base station. The results compared with wideband measurements provide better understanding of the propagation mechanism.

This paper describes a multichannel measurement system for the analysis of the radio channel of adaptive array antennas. It provides real-time recording of signals from multiple input channels. Due to this multielement reception, the incidence angles of the received signal components can be resolved. Wideband sounding provides the delay information. This allows the characterization of the two-dimensional radio channel of adaptive antenna systems in realistic environments. The system is based on a complex wideband radio channel sounder and a fast RF switch. As an example, the system allows measurement of complex impulse responses for a 16-element array with 17 ns delay resolution, and a delay range of 4.3 /spl mu/s for a 26 m/s mobile speed. The continuously recorded path lengths can be over one hundred meters. Practical channel measurements have been performed with a linear array of 8 elements. In these measurements the received signal components could be separated with 13/spl deg/ angular and 20 ns delay resolution. The developed method provides a novel approach to the two-dimensional analysis of the mobile environment.

This paper describes the problems caused by the phase noise in the development of micro- and millimeterwave range crosscorrelation type wideband channel sounders. The procedure to estimate the phase noise and its effect on the dynamic range of the impulse response measurement is given. It can be seen that the effect of the phase noise becomes more significant as the measurement frequency increases. With typical components a dynamic range of 35 dB was estimated at 60 GHz.