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Characterization and Enhancement of Antenna System Performance in Compact MIMO Terminals

Plicanic, Vanja LU (2011)
Abstract (Swedish)
Popular Abstract in Swedish

I dagens nya cellulära kommunikationssystem betraktas användandet av multipla mottagarantenner i kompakta användarterminaler som en nödvändighet för att kunna utnyttja fördelarna med diversitet och MIMO (Multiple Input Multiple Output) teknik och därmed uppnå god celltäckning och hög dataöverföringshastighet. Den senaste utbyggnaden av det cellulära kommunikationssystemet LTE (Long Term Evolution) runt om i världen, som kräver MIMO teknik för kommunikation i nedlänk, bekräftar hur brådskande det är att praktiskt kunna införa kompakta och optimala multipla antennlösningar i kommersiella terminaler som t.ex. ”smart phones”. De utmaningar som tillämpningen av multipla antenner medför är dock inte... (More)
Popular Abstract in Swedish

I dagens nya cellulära kommunikationssystem betraktas användandet av multipla mottagarantenner i kompakta användarterminaler som en nödvändighet för att kunna utnyttja fördelarna med diversitet och MIMO (Multiple Input Multiple Output) teknik och därmed uppnå god celltäckning och hög dataöverföringshastighet. Den senaste utbyggnaden av det cellulära kommunikationssystemet LTE (Long Term Evolution) runt om i världen, som kräver MIMO teknik för kommunikation i nedlänk, bekräftar hur brådskande det är att praktiskt kunna införa kompakta och optimala multipla antennlösningar i kommersiella terminaler som t.ex. ”smart phones”. De utmaningar som tillämpningen av multipla antenner medför är dock inte begränsade till enbart antennutformning och antennplaceringen i en terminal, utan sträcker sig även till att omfatta nära samverkan mellan antennsystemet, användaren och utbredningskanalen. Denna samverkan är dessutom inte statisk, vilket ställer krav på att antennsystemet ska vara adaptivt till det rådande tillståndet av hela kommunikationskanalen för att kunna försäkra hög prestanda. Denna doktorsavhandling riktar in sig på ett antal nyckelfrågor kring utformningen av antennsystem för kompakta multi-frekvens MIMO terminaler. Första delen av avhandlingen (Artikel I till III) handlar om prestanda- karakterisering av MIMO terminaler i realistiska användarutförande, med förutsättningen att terminalerna och antennsystemen är kompakta. Den andra delen av avhandlingen (Artikel IV till VI) beaktar två olika metoder för prestandaförbättring, båda lämpade för kompakta MIMO terminaler i realistiska användarutföranden och utbredningsscenarier. I denna del så fastställs fördelarna av harmoniseringen av multipla antennsystem med användaren och utbredningskanalen, med avseende på rekonfigurabilitet av antennstrålningsdiagram och kretsar för impedansmatchning. (Less)
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... (More)
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. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Bonek, Ernst, Vienna University of Technology, Wien, Austria
organization
publishing date
type
Thesis
publication status
published
subject
defense location
Lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
defense date
2011-06-14 10:15
ISBN
978-91-7473-120-0
language
English
LU publication?
yes
id
15f5ebc4-1f3e-4f31-9d8f-aa769e3408a7 (old id 1963011)
date added to LUP
2011-05-18 13:27:33
date last changed
2016-09-19 08:45:18
@misc{15f5ebc4-1f3e-4f31-9d8f-aa769e3408a7,
  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. <br/><br>
<br/><br>
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.<br/><br>
<br/><br>
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. <br/><br>
<br/><br>
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.<br/><br>
<br/><br>
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. <br/><br>
<br/><br>
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.<br/><br>
<br/><br>
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.},
  author       = {Plicanic, Vanja},
  isbn         = {978-91-7473-120-0},
  language     = {eng},
  title        = {Characterization and Enhancement of Antenna System Performance in Compact MIMO Terminals},
  year         = {2011},
}