The Unpredictable Future: Personal Networks Paving Towards 4G

In this paper we discuss how the network paradigm Personal Networks will become an evolutionary and revolutionary step for communication technology towards the fourth generation communication (4G). For 4G, not only higher data rates, user capacity, latency and data coverage are parameters of interest, but also technology convergence, personalisation and security play leading roles. In this paper we describe and discuss how Personal Network addresses exactly these issues, for which it will pave the technology development towards the envisioned 4G.
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RAMJEE PRASAD AND RASMUS L. OLSEN

Ramjee Prasad is Director of Center for Tele- infrastruktur (CTIF) at Aalborg University, Denmark

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WRAPPING A MOBILE ROBOT WITH RT-CORBA

ABSTRAC

Building complex controllers is a major challenge and it is widely accepted that object technology can help with the problem. This is of special relevance in the field of complex robot control, in particular when distribution is necessary. CORBA is a suitable technology for deployment and is well demon- strated in the experimental field and in commercial robots. In this paper we describe the implementation of a real-time object wrapper for a mobile robot using Real-time CORBA technology. This type of wrapping enables the implementation of networked robot control systems with increased degrees of predictability.

Keywords: Robot control software, distributed control, object wrappers, CORBA, Real-time CORBA.

INTRODUCTION

The nature of applied research in intelligent robot controllers makes having a versatile soft- ware architecture a real need for exploring al- ternative designs in robotic mind construction. Flexibility, modularity, maintainability and even hot-replaceability of components are major non- functional needs for such systems. While some effort has been spent on genericity is robot control system construction, most research has been cen- tered around the provision of ultimate architec- tures and reusable software components to fulfill specific missions in the robot controller. Less effort has been put, however, in the development of a robust and flexible underlying software platform where to explore such designs and components.

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Ricardo Sanz∗,1 Adolfo Hernando∗ Carlos Mart ́ınez∗ Ignacio L ́opez∗

∗ Autonomous Systems Laboratory Universidad Polit ́ecnica de Madrid, Spain

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NUMERICAL ANALYSIS OF A SMALL ULTRA WIDEBAND MICROSTRIP-FED TAP MONOPOLE ANTENNA

Abstract—This paper presents a planar microstrip-fed tab monopole antenna for ultra wideband wireless communications applications. The impedance bandwidth of the antenna is improved by adding slit in one side of the mono pole, introducing at apered transition between the mono poleand the feedline,and adding two-step stair casenotchin the ground plane. Numerical analysis for the antenna dimensional parameters using Ansoft HFSS is performed and presented. The proposedantennahasasmallsizeof16×19mm,andprovidesan ultra wide bandwidth from 2.8 to 28 GHz with low VSWR level and good radiation characteristics to satisfy the requirements of the current and future wireless communications systems.

1. INTRODUCTION

From mobile telephones to wireless Internet access to networked appliance sand peripherals,there is anincreasing reliance on wireless communications to provide functionality for products and services.Therefore,the technologies for wireless communications always need further improvement to satisfy higher resolution and data requirements. That is why ultra wideband (UWB) communications systems covering 3.1 GHz to 10.6 GHz released by the Federal Communications Commission (FCC) in 2002 [1] are currently under development.However,thereisalwaysanincreasingdemandfor smallersize,andgreatercapacitiesandtransmissionspeeds,which will certainly require more operating bandwidth in the near future.

Inthelastfewyears,researchershaveinvestigatedseveralkindsof microstrip slot and printed antennas for UWB applications [2–15]. One

of the best antennas in the last decade is the tap monopole antenna. The planar tap monopole antennas have been adopted and studied extensively for UWB communications systems because of their many appealing features. These features include wide impedance bandwidth, simplestructure,smallsize,lowprofile,andomni-directionalradiation patterns.Numberofwidebandtapmonopoleconfigurations,suchas rectangular,elliptical,pentagonal,andhexagonalhasbeenproposed for UWB applications [5:15]. Wide impedance bandwidth of (1:1.7), (1:2.25),(1:2.87),(1:3.4),(1:3.5),(1:3.7),(1:3.75)and(1:10.7)for VSWR<2,andanantennasizeof20,24,20,23,16,26,30,andmore than52mmarereportedin[7–14],respectively.

Recently,wepresentedamodifiedprintedtapmonopoleantenna forUWBapplicationswithaslit,notchedgroundplane,andtapered transition between the tap monopole and the feed line with a very wideimpedancebandwidthof(1:7.9)[15].Inthispaper,wepresent numerical analysis of the antenna in [15] to show the effect of each dimensional parameter. The numerical analysis results in a much betterbandwidthof(1:10),withalowVSWRleveloflessthan1.75, andasmallsizeof16mm,whichissmallerthantheantennaspresented in [2–14]. The results in this paper are obtained from Ansoft HFSS simulations,whicharebasedontheFiniteElementMethod(FEM). Verification of the final results is performed using a FDTD based code designed by the author.

2. ANTENNA GEOMETRY AND PARAMETERS

The geometry and parameters of the proposed broadband tap monopole antenna are depicted in Fig. 1. The antenna is printed on an FR4Epoxysubstratewitharelativedielectricconstant(εr)of4.4,a tangentialloss(tanσ)of0.02,athickness(h)of1.6mm,awidth(Ws) of 16 mm and a length (Ls ) of 19 mm. The basic antenna structure consistsofarectangularpatchwithanarrowslit,ataperedtransition, afeedline,andatruncatedgroundplanewithatwo-stepstaircase notch.

The rectangular patch has a width P1 and a height P2. A narrow slit of width S1 and depth S2 is cut on the patch’s right side and placed at a distance S3 away from the lower right corner of the patch. The slit is placed to create additional path for the surface current, which producesan additional resonance, andasaresult, increases the band width when the dimension sareproperly chosen,whichis proven in [15] by comparing VSWRs for antennas with and without slit. Additionally, because this slotis very narrow itdoes not disturb the existing resonances of the tap monopole.

A. A. Eldek

Department of Computer Engineering 

Jackson State University JSUBox17098,Jackson,MS39217-0198,USA

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SMART ANTENNA BASE STATION OPEN ARCHITECTURE FOR SDR NETWORKS

ABSTRACT

Software-defined radio system architecture must be openly structured to various system standards. It should also provide capability for distributed processing, object-oriented design, and software controllability. This implies that the software to be used in the SDR system should be independent of a given hardware platform. In order to achieve these goals, the proposed SDR system utilizes modularization to maximize hardware reuse and design flexibility, which provides the system reconfigurability. The objective of this article is to provide an open architecture of a smart antenna base station (SABS) operating in the SDR with architecture that is object-oriented and software-controlled. For this purpose, the software and hardware of a SABS is first modularized and partitioned into modules, respectively. Then the interface among the modules is specified to determine the smart antenna

application programming interface proper for the SDR network. The suitability of the proposed open architecture of SABS is verified through a design example of SABS implemented in accordance with the proposed architecture. The performance of the proposed system is shown in practical signal environments of CDMA2000 1X with commercial handsets operating at various data rates ranging from 9.6 to 153.6 kb/s in terms of frame error rate and signal- to-Interference-plus-noise ratio, which is dramatically improved through the nicely shaped beam pattern.

INTRODUCTION

The objective of developing software-defined 

radio ( SDR) technology is to realize plural system 

standards on a single hardware platform 

that is implemented mainly with high-speed programmable 

digital signal processing devices [1]. 

A desired system standard can be selected by 

choosing a proper software module. 

This article addresses the problem of designing 

the hardware and software architecture of a smart 

antenna base station (SABS) that operates in an 

SDR network. A design example of SABS architecture 

that satisfies the requirements of SDR 

functionalities is also provided in this article. We  

propose a hardware platform employing the open 

architecture of SABS, with which one can implement 

the multimode SDR system by selecting the

mo dularized software. Note that the hardware 

platform itself remains unchanged while selecting 

a desired system standard among several different  

standards [2].

The SDR technology includes the design of 

both hardware and software modules. The hardware 

module is reconfigured by the software 

module, which means that a given hardware  

platform is converted into a specific system standard 

or special-purpose communication system 

depending on the changes in the software module.  I

t is key to SDR technology that a system 

update or an addition/deletion/modification of 

services can be performed extremely easily without 

changing the existing hardware [3].

In this article we present an open architecture 

of SABS that is suitable to the SDR network 

and allows one to fully exploit the merits of 

both smart antenna and SDR technologies. The 

proposed architecture has been applied to implement 

a system of SABS, which includes the modulation 

and demodulation parts of the SABS 

together with the interfaces with the SDR network, 

as well as that among the modules within 

the SABS. The suitability of the proposed open 

architecture is demonstrated through a quantitative 

analysis obtained through various experimental 

measurements provided from the design 

example of SABS.

The main contributions of this article can be 

summarized as follows. First, SABS has been partitioned 

into small modules in accordance with 

the function of each module. The interconnections 

among modules are specified such that the 

clock/control signals and command data buses 

between all connected modules operate properly. 

Second, a new SABS open architecture (SABS 

OA) together with a smart antenna application 

programming interface (SA API) are presented 

such that the required features of the SDR system 

are fully satisfied in the SABS. Third, the 

SABS OA and SA API presented in this article 

have been developed in such a way that the 

vari

ous beamforming algorithms are applicable to the

roposed OA. This means that one can receive 

any of the beamforming algorithms suitable to a 

given signal environment from the SDR network 

through the software download procedure. Finally, 

utilizing the OA proposed in this article, we 

present an example of SDR-based SABS to experimentally 

show the feasibility of the proposed 

SABS OA in a practical signal environment.

NAMKYU RYU, YUSUK YUN, AND SEUNGWON CHOI, HANYANG UNIVERSITY, SEOUL, KOREA

RAMESH CHEMBIL PALAT AND JEFFREY H. REED,

VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY

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