| 1. |
- Bolin, Thomas, et al.
(author)
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Two-antenna receive diversity performance in indoor environment
- 2005
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In: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 41:22, s. 1205-1206
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Journal article (peer-reviewed)abstract
- Receive diversity gain performance of a two-antenna setup in an office environment is reported. The terminal is handheld in front of the user simulating a data mode scenario while walking around. The dual polarised base station sector antenna is placed at the end of a corridor. The results indicate that experimentally achieved diversity performance is similar to previously predicted theoretical data.
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| 2. |
- Plicanic, Vanja, et al.
(author)
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Actual diversity performance of a multiband diversity antenna with hand and head effects
- 2009
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In: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 57:5, s. 1547-1556
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Journal article (peer-reviewed)abstract
- Using the metric actual diversity gain (ADG), diversity performance is investigated for a compact mobile terminal prototype with two internal, triple frequency band antennas in four different cases of user interaction. ADG is presented as a preferred alternative to apparent diversity gain and effective diversity gain. Absorption due to user proximity causes degradation and imbalance in mean effective gain of the antennas over the frequency bands, contributing to a degradation in diversity performance. However, user-induced changes in the antenna patterns cause a decrease in correlation in the low frequency band, which facilitates increased diversity gain. The study reveals that a significant net diversity gain, i.e., ADG of 5-8 dB compared to a single antenna prototype, can be achieved using multiband antennas in the proximity of a user, even at low frequencies for antennas with high mutual coupling.
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| 3. |
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| 4. |
- Plicanic, Vanja, et al.
(author)
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Antenna diversity evaluation for mobile terminals
- 2006
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In: European Space Agency, (Special Publication) ESA SP. - 0379-6566 .- 1609-042X. ; 626 SP
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Conference paper (peer-reviewed)abstract
- In this paper we are focusing on the practical, engineering way of evaluating and characterizing the multi-channel antenna solutions on the mobile terminal. Two methods of calculating the parameters, describing the diversity performance, are described and the practical use of the methods in simulations and measurements are presented and evaluated. The time saving aspect of using the scattering parameters is lifted forward but also its limitations. For comparison, a statistical method for calculating Diversity Gain is also presented. This evaluation is performed for two multi-channel antenna solutions with different characteristics for the purpose of characterizing different diversity performances.
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| 5. |
- Plicanic, Vanja, et al.
(author)
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Capacity maximisation of a handheld MIMO terminal with adaptive matching in an indoor environment
- 2011
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In: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 47:16, s. 900-901
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Journal article (peer-reviewed)abstract
- This letter reports the capacity performance of a handheld dual-band dual-antenna compact MIMO terminal, which utilizes uncoupled adaptive impedance matching for capacity maximisation. The capacity is evaluated at 0.825 GHz and 2.35 GHz in an indoor office environment. The results show that adaptive matching enhances capacity by up to 44% and 22% at the low and high frequency bands, respectively, relative to no matching. At the low band, the capacity gain is attributed to both increased received power and decreased channel eigenvalue dispersion, whereas at the high band, the capacity gain is only due to increased power.
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| 6. |
- Plicanic, Vanja, et al.
(author)
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Channel capacity performance of multi-band dual antenna in proximity of a user
- 2009
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In: 2009 IEEE International Workshop on Antenna Technology: Small Antennas and Novel Metamaterials (IWAT). - 9781424443956 ; , s. 41402-41402
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Conference paper (peer-reviewed)abstract
- This paper presents an evaluation of single input single output (SISO), single input multiple output (SIMO) and multiple input multiple output (MIMO) channel capacities for a dual antenna prototype in proximity of a user. The dual antenna prototype mimics today’s small mobile phone design in size and in comprising internal, compact, multi-band antennas. Four different user cases are evaluated by measuring the antenna radiation performance for each of the different interactions between a phantom user and the antenna. Measurements of a single antenna prototype with user are also performed for comparisons between the SISO case and the SIMO/MIMO cases. Depending on the user interaction case, the MIMO capacity of the prototype is between 40-90% at 850 MHz and 60-80% at 2100 MHz higher than the SISO performance of the single antenna prototype or the best antenna on the dual antenna prototype.
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| 7. |
- Plicanic, Vanja
(author)
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Characterization and Enhancement of Antenna System Performance in Compact MIMO Terminals
- 2011
-
Doctoral thesis (other academic/artistic)abstract
- Co-band multiple-antenna implementation in compact user terminals is necessary for harvesting the full potential of diversity and multiple-input multiple-output (MIMO) technology in cellular communication systems. The recent worldwide deployment of Long Term Evolution (LTE), which requires the use of MIMO technology in the downlink, adds to the urgency of achieving both practical and optimal multiple-antenna systems in user terminals. Contrary to conventional understanding, an optimal multiple-antenna implementation does not only involve the design and placement of antenna elements in the terminals, but extends beyond the antenna elements and common antenna parameters to comprise interactions with the near field user and the propagation environment. Moreover, these interactions are non-static, which implies that the multiple-antenna system must adapt to the prevailing overall communication channel in order to assure the highest performance gains. This doctoral thesis aims to address several key issues in optimal multiple-antenna system design for compact multi-band MIMO terminals, with the first half (Papers I to III) focusing on the performance characterization of such terminals in the presence of user interaction and propagation channel, under the challenging constraint that the terminals are compact. The second half of the thesis (Papers IV to VI) considers two performance enhancement approaches suitable for compact MIMO terminals in realistic usage conditions. In particular, the potential benefits of harmonizing compact multiple-antenna systems with the propagation channel and user influence are determined with respect to reconfigurability in antenna patterns and impedance matching circuits. In Paper I, the diversity performance of internal multiple antennas with multi-band coverage in a mock-up with the size of a typical mobile handset is investigated in different user interaction scenarios. For comparison, a second mock-up with only one multi-band antenna is also evaluated in the same user cases. An ideal uniform propagation environment is assumed. The performance at frequency bands below and above 1 GHz are presented and analyzed in detail. Paper II extends the study in Paper I by evaluating the single-input multiple-output (SIMO) and MIMO capacity performance of the same antenna prototypes under the same user interaction scenarios and propagation environment. In Paper III, the impacts of gain imbalance and antenna separation on the throughput performance of a dual-dipole configuration are studied at frequencies below and above 1 GHz in a repeatable dynamic multi-path environment, using a live HSPA network. Since the compactness of a user terminal has implications on the antenna separation and gain imbalance of the multiple antennas, the focus is to gain knowledge on how these two factors affect the end user experience in practice. In Paper IV, three simple dual-antenna topologies implemented in compact smart phone prototypes of identical form factors are evaluated in MIMO channel measurements in noise-limited and interference-limited urban scenarios. Each dual-antenna topology is intentionally designed to provide a distinct set of antenna patterns. The goal is to investigate the potential of antenna system design as one of the key performance differentiators in real terminal implementations. Paper V extends the work in Paper IV by introducing user interaction to the same MIMO channel measurement setup. Furthermore, the focus of this paper is on the evaluation of both the average and local channel performances and their potential enhancements. Finally, Paper VI ascertains the potential capacity gains of applying uncoupled adaptive matching to a compact dual-antenna terminal in an indoor office environment, under a realistic user scenario. The performance gains are evaluated by means of extensive MIMO channel measurements at frequency bands below and above 1 GHz.
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| 8. |
- Plicanic, Vanja, et al.
(author)
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Diversity mechanisms and MIMO throughput performance of a compact six-port dielectric resonator antenna array
- 2010
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In: 2010 International Workshop on Antenna Technology (iWAT). - 9781424448838
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Conference paper (peer-reviewed)abstract
- This paper demonstrates multiple-input-multiple-output (MIMO) throughput performance of a six-port dielectric resonator antenna (DRA) array for Wireless-LAN applications in a measured indoor office environment when a six-port dual-polarized patch array is used at the transmitter. The throughput was obtained using an IEEE802.11n/Draft 5.00 simulator for measured channels with different antenna and propagation setups. The throughput performance of the patch-DRA array set-up is found to be similar to that of a set-up with six-port monopole arrays at the receive and transmit ends in the non-line-of sight (NLOS) environment. The compact design of the DRA array causes lower port efficiencies relative to those of the monopole array, notwithstanding the compact DRA array is shown in this paper to effectively utilize angle, polarization and spatial diversity mechanisms to achieve comparable throughput performance.
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| 9. |
- Plicanic, Vanja, et al.
(author)
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Diversity mechanisms of a compact dielectric resonator antenna array for high MIMO throughput performance
- 2009
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Conference paper (other academic/artistic)abstract
- The multiple-input-multiple-output (MIMO) throughput of a given wireless system is a better indication of end user experience, as compared to conventional MIMO performance metrics such as capacity and diversity gains. This paper demonstrates throughput performance of a six-port dielectric resonator antenna (DRA) array for Wireless-LAN (WLAN) applications in a measured indoor office environment when a six-port dual-polarized patch array is used at the transmit end. The throughput was obtained using an IEEE 802.11n/Draft 5 simulator for measured channels with different antenna and propagation setups. The throughput performance of the patch-DRA array set-up is found to be similar to that of a set-up with six-port monopole arrays at the transmit and receive ends in the non-line-of sight (NLOS) environment. Even though the compact design of the DRA array causes lower port efficiencies relative to those of the reference monopole array, the compact DRA array can effectively utilize angle, polarization and spatial diversity mechanisms to achieve comparable throughput performance.
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| 10. |
- Plicanic, Vanja, et al.
(author)
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Experimental evaluation of MIMO terminal antenna configurations in noise- and interference-limited urban scenarios
- 2011
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In: Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP). - 9788882020743
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Conference paper (peer-reviewed)abstract
- In this paper, we compare capacity performances of three terminal dual-antenna configurations at 2.65 GHz based on extensive 2 by 2 multiple-input multiple-output (MIMO) channel measurements in an urban macrocellular environment. Both noise- and interference-limited scenarios are investigated. Our results show that, on average over the measurement route, the capacity performance is mainly determined by the received power. However, locally along the route, the eigenvalue dispersion of the channel can be the dominant factor that influences the capacity performance. In addition, significant differences in the local performances of the terminal antenna configurations along the route give an indication that antenna reconfigurability is a promising approach to maximize capacity.
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