Modeling of wide-band MIMO radio channels based on NLoS indoor measurements

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Experimental study of MIMO-OFDM transmissions at 94 GHz in indoor environments

Millimeter wave (mm-wave) frequencies have been proposed to achieve high capacity in 5G communications. Although meaningful research on the channel characteristics has been performed in the 28, 38and 60 GHz bands ─in both indoor and short-range scenarios─,only a small number of trials (experiments) have been carried out in other mm-wave bands. The objective of this work is to study the viability and evaluate the performance of the 94 GHz frequency band for MIMO-OFDM transmission in an indoor environment. Starting from a measurement campaign, the performance of MIMO algorithms is studied in terms of throughput for four different antenna configurations.This work was supported in part by the Ministerio de Economía y Competitividad MINECO, Spain under Grant TEC2016-78028-C3-2-P, and in part by the European FEDER funds

Design considerations of MIMO antennas for mobile phones

YesThe paper presents a new modeling and design concept of antennas using polar- ization diversity of 2 £ 2 and 3 £ 3 Multiple Input Multiple Outputs (MIMO) system that is proposed for future mobile handsets. The channel capacity is investigated and discussed over Raleigh fading channel and compared to a linear/planner antenna array MIMO channel. The capacity is also discussed over three types of power azimuth spectrums. The results are compared to the constraints capacity limits in which the maximum capacity observed

Methods and criteria for performance analysis of multiantenna systems in mobile communications

Multiple-input multiple-output (MIMO) technique is one of the most promising solutions for increasing reliability and spectral efficiency of the radio connection in future mobile communication systems. The performance potential of MIMO systems is well established from theoretical point of view. However, much effort is still needed in the experimental verification of those systems using realistic antennas and channels. It is widely accepted that the antenna properties are of significant importance regarding the performance of single-input single-output (SISO) systems. However, the effect of the antennas on MIMO systems has not been thoroughly studied. Due to the complexity of MIMO systems, evaluation of MIMO antennas becomes increasingly cumbersome and time-consuming process in comparison to simpler systems. In the first part of this work an advanced antenna evaluation technique called experimental plane-wave based method (EPWBM) is generalized and validated to cover MIMO systems. This work is the extension of the previous work where the method has been used in the analysis of SISO systems. The EPWBM is based on the measured or simulated complex 3-D radiation patterns of the antennas and measured directional radio channel data. The EPWBM simplifies antenna evaluation process in comparison to traditional means since the same channel library can be utilized in the evaluation of several antenna systems without performing the same measurements for each prototype antennas separately. It is verified that the EPWBM is sufficiently reliable in comparing the performance of prototype antennas. In the second part of the work new quality factors for MIMO system evaluation enclosing traditional systems as special cases have been developed. The MIMO channel correlation matrix is formulated so that it reveals the ability of MIMO antenna systems to transfer signal power from a transmitter to a receiver and to utilize parallel spatial channels. It is also verified that correct normalization of the channel matrices is of significant importance in the MIMO antenna evaluation. This approach gives comprehensive framework for MIMO antenna evaluation, which takes into account both realistic antenna and channel properties. In the last part of the work insight into the performance of different antennas in different signal propagation environments is given. The performance of the antennas depends on the signal-to-noise-ratio and on the outage probability level considered. Although MIMO systems are based on the utilization of parallel spatial channels, the capability of the system to transfer signal power plays a significant role especially with small MIMO systems. In the realistic dynamic channels the capacity variation is larger than in the ideal channels, which are based on the identically and independently distributed (iid) channel assumption. Large performance variations occur in the realistic channels with directive antennas, when antennas are rotated in the usage environment, whereas omnidirectional ones are more robust but are difficult to realize in practice. The largest differences between the antennas are found at the low outage probability levels due to different radiation properties of the antennas. The systems with the cross-polarized antennas have smaller eigenvalue dispersion and are more robust in performance for the variations of the channel than the systems with co-polarized antennas. On the other hand, the co-polarized antennas possess better capability to transfer signal power and are more robust in performance for the antenna array orientation. From practical point of view, the dual-polarized antennas seem to be the most feasible candidates to be used in MIMO antenna systems due to compact structure, and indoor seems to be the most suitable for MIMO applications due to typically scatter-rich channel.Multiple-input multiple-output (MIMO) tekniika on yksi lupaavimmista ratkaisuista lisätä radioyhteyden luotettavuutta ja spektritehokkuutta tulevaisuuden matkaviestinjärjestelmissä. MIMO järjestelmien suorituskykypotentiaali on teoreettisesti todistettu. Paljon työtä tarvitaan kuitenkin vielä kokeelliseen järjestelmätestaukseen käyttäen realistisia antenneja ja kanavia. On laajasti hyväksyttyä että antennien ominaisuudet ovat merkityksellisiä single-input single-output (SISO) järjestelmien suorituskyvyn kannalta. Antennien vaikutusta MIMO-järjestelmiin ei ole kuitenkaan perusteellisesti tutkittu. MIMO-järjestelmien lisääntyneestä monimutkaisuudesta johtuen, verrattuna yksinkertaisempiin järjestelmiin, MIMO antennien suorituskyvyn arviointi hankaloituu ja vie enemmän aikaa. Työn ensimmäisessä osassa uusi antennien arviointitekniikka nimeltään kokeellinen tasoaaltoihin perustuva menetelmä (EPWBM) on yleistetty käsittämään MIMO järjestelmät ja sen tarkkuus on arvioitu. Tämä työ on laajennus aikaisempaan työhön jossa menetelmää on käytetty SISO-järjestelmien arviointiin. EPWBM perustuu mitattuihin tai simuloituihin antennien kompleksisiin 3-D suuntakuvioihin ja mitattuun suuntatiedon sisältämään kanavadataan. EPWBM yksinkertaistaa antennin suorituskyvyn arviointia perinteisiin menetelmiin verrattuna, koska sama kanavamittausaineisto voidaan hyödyntää usamman antennisysteemin arvioinnissa tekemättä samoja mittauksia jokaiselle antenniprototyypille erikseen. On osoitettu että EPWBM on suhteellisen luotettava prototyyppiantennien suorituskyvyn vertailussa. Työn toisessa osassa on kehitetty uusia hyvyyslukuja MIMO-järjestelmien suorituskyvyn arviointiin sisältäen perinteiset järjestelmät erikoistapauksina. MIMO-kanavamatriisi esitetään siten että se paljastaa MIMO-antennijärjestelmien kyvyn siirtää signaalitehoa lähettimen ja vastaanottimen välillä ja hyödyntää rinnakkaisia kanavia. On myös todistettu että oikeanlainen kanavamatriisien normalisointi on erittäin merkittävää MIMO-antennivertailussa. Tämä lähestymistapa antaa kattavat puitteet MIMO-antennien suorituskyvyn arviointiin ottaen huomioon todelliset antennien ja kanavan ominaisuudet. Työn viimeisessä osassa annetaan käsitys erilaisten antennien suorituskyvystä erilaisissa signaalin etenemisympäristöissä. Antennien suorituskyky riippuu signaalikohinasuhteesta ja tarkasteltavan signaalin luotettavuustasosta. Vaikka MIMO-järjestelmät perustuvat rinnakkaisten kanavien hyödyntämiseen järjestelmän signaalitehon siirto-ominaisuudet ovat merkittäviä erityisesti pienillä MIMO järjestelmillä. Realistisissa dynaamisissa kanavissa kapasiteetinvaihtelu on suurempaa kuin ideaalisissa kanavissa jotka perustuvat oletukseen että signaalit ovat riippumattomasti ja identtisesti jakautuneita (iid). Suurta suorituskykyn vaihtelua esiintyy realistissa kanavissa suuntaavilla antenneilla, kun antenneja pyöritetään käyttöympäristössä, kun taas ympärisäteilevät antennit olisivat jäykempiä suorituskyvyn kannalta mutta käytännössä vaikeampia toteuttaa. Suuremmat erot antennien välillä on löydettävissä matalalta signaalin luotettavuustasolta johtuen antennien erilaisista säteilyominaisuuksista. Kaksipolarisaatioantennijärjestelmillä on pienempi ominaisarvohaje ja niiden suorituskyky on jäykempi kanavan vaihteluille kuin yksipolarisaatioantennijärjestelmä. Toisaalta yksipolarisaatioantenneilla on paremmat signaalitehon siirto-ominaisuudet ja suorituskyky vaihtelee vähemmän antennin katselusuunnan funktiona. Käytännön näkökulmasta katsoen kaksipolarisaatioantennit näyttävät olevan kaikkein toteuttamiskelpoisin vaihtoehto käytettäväksi MIMO-systeemeissä johtuen niiden kompaktista rakenteesta, ja sisätila näyttää olevan sopivin ympäristö MIMO-sovelluksiin johtuen tyypillisesti sirontarikkaasta kanavasta.reviewe

The Investigation of Polarization Diversity in MIMO System at 2.4 GHz

This paper describes the concept of multiple input multiple output (MIMO) system using polarization diversity that can enhance the channel capacity and increased the data output performance of the system. The microstrip antenna array is designed, fabricated and measured at the desired operating frequency for this measurement. Computer Simulation Technology (CST) software is used to design and simulate the microstrip antenna array. The simulation and measurement data results are compared and discussed. The fabricated microstrip antenna is used to develop the Radio Frequency (RF) MIMO test bed system. The system measurement has been conducted in Microwave Laboratory at Faculty of Electronic and Computer Engineering, University Technical Malaysia Melaka at the operating frequency of 2.4 GHz. The spatial diversity and polarization diversity are applied in measurement campaign to investigate the performance of the wireless MIMO channel. The data obtained from the measurement is processed using MATLAB software in order to calculate the MIMO channel capacity. The analysis has been focused on the effect of the MIMO channel capacity due to the proposed measurement setup configurations. The channel capacity is increased from 0.03 b/s/Hz to 0.09 b/s/Hz when polarization diversity is applied at both transmitter and receive

Evaluation of performance of mobile terminal antennas

Fast development of new mobile communications equipment results in demand for fast and reliable evaluation methods to estimate the performance of mobile terminals because the performance of antennas located on the terminals varies in different multipath propagation environments. Two methods presented in this thesis provide new possibilities in antenna design because, from now on, the performance of new antennas can be tested already before a prototype antenna is constructed by using existing radio channel libraries and simulated radiation patterns of the antennas. The performance can be estimated by calculating the mean effective gain (MEG) of the antenna using the elevation power distribution or by a plane wave -based method using sets of incident plane waves and the radiation pattern of an antenna. In addition to different propagation environments, the effects of the user on performance can be included in the evaluation. In this thesis, estimating the MEG of different antennas using the elevation power distribution and the power patterns of the antennas is shown to be an accurate and fast method by comparing the results with direct radio channel measurements. The mean difference between the methods is −0.18 dB with standard deviation of 0.19 dB. The usefulness of the evaluation method is demonstrated by evaluating the performance of several antennas located on mobile terminals. The antenna evaluation provided important and unique knowledge of the effect of both the environment and the user on performance. Because in calculating the radiation efficiency of the antenna we assume uniform incident field, the efficiency can result in a performance estimation that does not correspond to real usage situations. Therefore, including the environmental effects in the evaluation procedure is important, although the effect of the antenna is more important than the effect of the environment on MEG. It was noticed with calculated Gaussian-shaped beams that tilting or changing the beamwidth of a mobile terminal antenna has an effect of about 2 dB on MEG in multipath environments. Matching the polarization of the antenna to that of the environment can improve the performance more. A novel incident plane wave -based tool has been developed for evaluating the performance of antenna configurations designed for diversity and Multiple-Input Multiple-Output (MIMO) systems. In this thesis, the instantaneous joint contribution of incident field consisting of a number of extracted plane waves and the complex three-dimensional radiation pattern of the antenna is shown to be accurate and extremely fast way to estimate the diversity advantages of different antenna configurations in time-variable radio channels. The difference between the diversity gains achieved by the plane wave -based method and by the direct radio channel measurements is on average less than 0.9 dB. Moreover, the radio channel can be exactly the same for all antenna configurations under test. Furthermore, this thesis includes evaluation of the performance of different MIMO antenna configurations. The studied antenna configurations have been selected from the 16×64 MIMO channel measurement data. A novel way of using one omnidirectional reference antenna in a normalization procedure is shown to be reasonable especially in cases of antenna arrays consisting of directive elements. Three different propagation environments are used as evaluation platforms. The azimuth orientation of mobile terminal antennas may influence the performance of a MIMO antenna configuration significantly. In MIMO configurations compact dual-polarized receiving antennas provide capacity performance almost equal to the arrays employing single polarization.reviewe

Dual-Polarized Ricean MIMO Channels: Modeling and Performance Assessment

In wireless communication systems, dual-polarized (DP) instead of single-polarized (SP) multiple-input multiple-output (MIMO) transmission is used to improve the spectral efficiency under certain conditions on the channel and the signal-to-noise ratio (SNR). In order to identify these conditions, we first propose a novel channel model for DP mobile Ricean MIMO channels for which statistical channel parameters are readily obtained from a moment-based channel decomposition. Second, we derive an approximation of the mutual information (MI), which can be expressed as a function of those statistical channel parameters. Based on this approximation, we characterize the required SNR for a DP MIMO system to outperform an SP MIMO system in terms of the MI. Finally, we apply our results to channel measurements at 2.53 GHz. We find that, using the proposed channel decomposition and the approximation of the MI, we are able to reproduce the (practically relevant) SNR values above which DP MIMO systems outperform SP MIMO systems.Comment: submitted to the IEEE Transactions on Communication