| 1. |
- Harrysson, Fredrik, et al.
(författare)
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The composite channel method : Efficient experimental evaluation of a realistic MIMO terminal in the presence of a human body
- 2008
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Ingår i: 2008 IEEE 67th Vehicular Technology Conference-Spring, VTC. - 1550-2252. - 9781424416455 ; , s. 473-477
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Konferensbidrag (refereegranskat)abstract
- The immediate environment of the transmit (TX) and receive (RX) antennas, including the antenna casings and the users holding the antennas, has a strong impact on the propagation channel and thus on wireless systems. In this paper we experimentally evaluate a method that synthetically combines double-directional measurements of the propagation channel (without the user influence) with measured antenna patterns of antennas-plus-users, by comparing obtained sample results with direct measurements in the same environment. The measurements are done for a static microcell 8×4 MIMO scenario at 2.6 GHz. A realistic user phantom was used together with a test terminal prototype with four antenna elements, and a number of different configurations and orientations of the phantom were tested. In average over all test cases, the mean signal power deviation between composite channel method and measurements was well within 1 dB. The composite method shows 6% higher terminal antenna correlation but similar statistical distributions as the measured. The differences between the model and measurements for the strongest eigenvalue (relevant for MRC combining) was found to be within 1 dB above 10% outage level. Relative deviations in the ergodic MIMO capacity were smaller than 10%.
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| 2. |
- Alayon Glazunov, Andres, et al.
(författare)
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A note on the Mean Effective Radiated Power and the Mean Effective Receiver Sensitivity of mobile handheld terminals
- 2008
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Ingår i: 2008 IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting. ; , s. 1-4, s. 4471-4474
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Konferensbidrag (refereegranskat)abstract
- In this paper we introduce the Mean Effective Radiated Power (MERP) and the Mean Effective Radiated Sensitivity (MERS) as alternative figures of merit of the uplink and downlink communication performance of wireless handheld terminals. We show how they are related to the Mean Effective Gain (MEG), the total radiated power (TRP) and total receiver sensitivity (TRS).
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| 3. |
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| 4. |
- Alayon Glazunov, Andres, et al.
(författare)
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Fading characterization in a semi-anechoic chamber with artificial scatterers for Mean Effective Gain measurements of wireless handheld terminals
- 2008
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Ingår i: 2008 IEEE Radio and Wireless Symposium, RWS. ; , s. 611-614
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Konferensbidrag (refereegranskat)abstract
- This paper presents the methodology and corresponding analysis of the scattered field measurements in a semi-anechoic ferrite-lined chamber. The focus is on recreating a Rayleigh fading environment with realistic cross-polarization ratio (XPR) with the purpose of measuring the Mean Effective Gain (MEG) of mobile handheld terminal operating in the 900 MHz GSM band. The emulated XPR was similar in each of the studied scenarios and approximately equal to 12 dB. The Rayleigh fading hypothesis for the statistics of the envelope of the measured signals could not be rejected in most cases at the 95 % level with the Kolmogorov goodness-of-fit test.
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| 5. |
- Alayon Glazunov, Andres, et al.
(författare)
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Mean effective gain of antennas in a wireless channel
- 2009
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Ingår i: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725. ; 3:2, s. 214-227
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Tidskriftsartikel (refereegranskat)abstract
- The mean effective gain (MEG) is one of the most important parameters for the characterisation of antennas in wireless channels. An analysis of some fundamental properties of the MEG is provided and corresponding physical interpretations are given. Three points are analysed in detail: (i) closed-form expressions for MEG in a mixed environment with both stochastic and deterministic components are provided, showing that the MEG can be written as a sum of gains for the deterministic and stochastic components, (ii) it is shown that under some assumptions, the propagation channel and the antenna are equivalent in the sense that the impact of the channel cross-polarisation ratio (XPR) and the antenna effective cross-polar discrimination on the MEG are symmetrical, (iii) based on the fact that MEG depends on random variables, such as the XPR and antenna rotations because of user's movements, the average, the minimum and maximum MEG of antennas are defined, respectively. Finally, the maximum effective gain of antennas is derived and shown that it is bounded by 4 pi eta(rad), where eta(rad) is the radiation efficiency of the antenna.
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| 6. |
- Alayon Glazunov, Andres, et al.
(författare)
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On the mean effective gain expressed in terms of the spherical vector wave expansion of the electromagnetic field
- 2008
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Konferensbidrag (refereegranskat)abstract
- The mode expansion o®ers a general framework for the analysis of the interaction between antennas andpropagation channels. In this paper, the Mean E®ective Gain (MEG) of an antenna is expressed in termsof the spherical vector wave expansion of the electromagnetic ¯eld. An explicit expression of the MEG isprovided as a function of the normalized average power of modes excited in the propagation channel andthe correlation between the channel modes due to the polarization and spatial selectivity of plane wavesimpinging at the antenna.
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| 7. |
- Alayon Glazunov, Andres, et al.
(författare)
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Physical modelling of multiple-input multiple-output antennas and channels by means of the spherical vector wave expansion
- 2010
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Ingår i: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725. ; 4:6, s. 778-791
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Tidskriftsartikel (refereegranskat)abstract
- The authors propose a new physically motivated model that allows the study of the interaction between the antennas and the propagation channel for multiple-input multiple-output (MIMO) systems. The key tools employed in the model are the expansion coefficients of the electromagnetic field in spherical vector waves and the scattering matrix representation of the properties of the antenna. The authors derive the expansion of the MIMO channel matrix, H, in spherical vector wave modes of the electromagnetic field of the antennas as well as the propagation channel. The authors also introduce the channel scattering dyadic, C, with a corresponding correlation model for co-polarised and cross-polarised elements and introduce the concept of mode-to-mode channel mapping, the M-matrix, between the receive and transmit antenna modes. The M-matrix maps the modes excited by the transmitting antenna to the modes exciting the receive antennas and vice versa. The covariance statistics of this M-matrix are expressed as a function of the double-directional power-angular spectrum (PAS) of co-polarised and cross-polarised components of the electromagnetic field. Their approach aims at gaining insights into the physics governing the interaction between antennas and channels and it is useful for studying the performance of different antenna designs in a specified propagation channel as well as for modelling the propagation channel. It can furthermore be used to quantify the optimal properties of antennas in a given propagation channel. The authors illustrate the developed methodology by analysing the interaction of a 2 x 2 system of slant polarised half-wavelength dipole antennas with some basic propagation channel models.
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| 8. |
- Alayon Glazunov, Andres, et al.
(författare)
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Spherical Vector Wave Expansion of Gaussian Electromagnetic Fields for Antenna-Channel Interaction Analysis
- 2009
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 57:7, s. 2055-2067
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we introduce an approach to analyze the interaction between antennas and the propagation channel. We study both the antennas and the propagation channel by means of the spherical vector wave mode expansion of the electromagnetic field. Then we use the expansion coefficients to study some properties of general antennas in thosefields by means of the antenna scattering matrix. The focus is on the spatio-polar characterization of antennas, channels and their interactions. We provide closed form expressions for the covariance of the field multimodes as function of the power angle spectrum (PAS) and the channel cross-polarization ratio (XPR). A new interpretation of the mean effective gains (MEG) of antennas is also provided. The maximum MEG is obtained by conjugate mode matching between the antennas and the channel; we also prove the (intuitive) results that the optimum decorrelation of the antenna signals is obtained by the excitation of orthogonal spherical vector modes.
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| 9. |
- Gustafson, Carl, et al.
(författare)
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Directional analysis of measured 60 GHz indoor radio channels using SAGE
- 2011
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Ingår i: [Host publication title missing]. - 1550-2252. - 9781424483327
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Konferensbidrag (refereegranskat)abstract
- Abstract in Undetermined Directional properties of the radio channel are of high importance for the development of reliable wireless systems operating in the 60 GHz frequency band. Using transfer functions measured from 61 to 65 GHz in a conference room we have extracted estimates of the multi-path component parameters using the SAGE algorithm. In the paper we compare results for line-of-sight (LOS) scenarios and the corresponding non-line-of-sight (NLOS) scenarios and present values of the direction spread at the Tx and the Rx.
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| 10. |
- He, Ruisi, et al.
(författare)
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Measurement-based analysis of relaying performance for vehicle-to-vehicle communications with large vehicle obstructions
- 2017
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Ingår i: 2016 IEEE 84th Vehicular Technology Conference, VTC Fall 2016 - Proceedings. - 9781509017010
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Konferensbidrag (refereegranskat)abstract
- It has been widely recognized that relaying is an important method for increasing the reliability and spectral efficiency of communications systems, and it is thus helpful for improving the performance of vehicle-to-vehicle (V2V) communication systems. However, designing and evaluating V2V relay networks require understanding the effect of shadowing, as this critically impacts the performance of the relay system. Even though the theoretic performances of various relaying schemes have been well investigated, there is a lack of empirical test that incorporates realistic shadowing effects. In this paper, we analyze the performance of relaying transmission in V2V scenarios based on measurements in scenarios where shadowing occurs through large vehicles such as buses. We investigate several potential locations for the relay nodes, and the measurements are performed with two static transmitters (TX) and one dynamic receiver (RX). Outage probabilities of several relaying schemes such as multi-hop decode-and-forward, multi-hop amplify-and-forward, and diversity-amplify-and-forward are estimated and discussed based on the measured instantaneous end-to-end signal-to-noise ratio (SNR). It is found that: (i) shadowing effect caused by the bus between V2V line-of-sight (LOS) links increases the outage probability for the non-LOS (NLOS) direct transmission; (ii) using relay node on the bus roof can significantly improve transmission, however, a strong shadowing effect may reduces the acceptable communication distance of relaying scheme; and (iii) the diversity-amplify-and-forward relaying scheme generally has the best performance. Our results can be used to design a relay system for V2V communications.
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