Multisite Field Trial for LTE and Advanced Concepts

INTRODUCTION

The mobile Internet has finally arrived with theworldwide deployment of high-speed packetaccess (HSPA) networks and broad availabilityof third-generation (3G) terminals, mobilebroadband USB sticks, and, increasingly, note-books with integrated HSPA modules. With flat-rate data tariffs, the usage of mobile Internethas skyrocketed in 2008. Third-generation tech-nology was developed more than a decade ago,and the uptake after launch was below expecta-tions in many cases. There are various reasonsfor that, including initial lack of handset avail-ability and initial technology performance belowpredictions.

The Next Generation Mobile Networks(NGMN) Alliance has set out requirements forfuture mobile networks [1], and the Third Gen-eration Partnership Program (3GPP) is address-ing them with the development of long-termevolution (LTE). Among the requirements forLTE are increased average and peak data rates,reduced latency, spectrum flexibility addressingbandwidths of up to 20 MHz, and, last but notleast, reduced cost of ownership. The targets inNGMN and LTE are set challenges to ensure asignificant performance step from HSPA to anew technology generation.

The performance of LTE meets the essentialNGMN requirements, but not the preferred

requirements in important key performance indi-cators (KPIs) like spectral efficiency and cell-edge throughput. Therefore, development ofLTE technology is continuing beyond Release 8to address operator requirements as well asthose of the International TelecommunicationsUnion (ITU) for future technologies in thenewly identified spectrum. 3GPP has initiatedthe “LTE-Advanced” study item and definedrequirements in [2].

The research project Enablers for AmbientServices and Systems — Part C Wide Area Cov-erage (EASY-C) is developing technologies forfuture wireless systems such as LTE-Advanced.The special feature of EASY-C is that researchideas are tested in research field testbeds at thesystem level. In EASY-C, 16 partners worktogether across the value chain, including aca-demic institutions, mobile operators, networkinfrastructure, antenna, and test equipment pro-viders, terminal chipset vendors and semiconduc-tor companies, and network planning specialists.

OVERVIEW OF LTE RELEASE 8The radio interface of 3GPP LTE/SAE Release8 uses orthogonal frequency-division multipleaccess (OFDMA) with cyclic prefix in the down-link and single-carrier frequency-division multi-ple access (SC-FDMA) with cyclic prefix in theuplink. The physical layer of LTE is defined in abandwidth agnostic way and supports varioussystem bandwidths up to 20 MHz. Radioresources are subdivided into physical resourceblocks (PRBs) consisting of 12 subcarriers with15 kHz spacing and a time duration of 1 ms.PRBs are dynamically allocated to users in orderto realize multi-user diversity gain in both timeand frequency domains, leveraging adaptivemodulation and coding (AMC) with hybrid auto-matic repeat request (HARQ).

To meet the performance requirements [3],LTE Release 8 relies on multi-antenna-basedmultiple-input multiple-output (MIMO) trans-mission and reception techniques, with 2 × 2MIMO as the baseline for downlink and 1 × 2

IEEE Communications Magazine • February 200992 0163-6804/09/$25.00 © 2009 IEEE

ABSTRACT

The 3GPP LTE standard is stable now in its firstrelease (Release 8), and the question is howgood its performance is in real-world scenarios.LTE is also a good base for further innovations,but it must be proven that they offer perfor-mance advantages for the price of their complex-ity. This article evaluates the performance ofLTE Release 8 as a baseline and advanced con-cepts currently in discussion such as cooperativeMIMO based on system-level simulations, andmeasurements in the laboratory and a multisitefield testbed within the EASY-C project.

LTE — 3GPP RELEASE 8

Ralf Irmer, Vodafone

Hans-Peter Mayer, Andreas Weber, Volker Braun, Michael Schmidt, Michael Ohm, and Norbert Ahr,

Alcatel-Lucent Bell Labs

André Zoch, Signalion GmbH

Carsten Jandura, Patrick Marsch, and Gerhard Fettweis, Technische Universität Dresden

Multisite Field Trial for LTE and Advanced Concepts

IRMER LAYOUT 1/19/09 3:41 PM Page 92

IEEE Communications Magazine • February 2009 93

MIMO for uplink. However, higher order anten-na configurations are supported. In the downlinkclosed-loop MIMO with code-book-based linearprecoding can be applied, which allows for spa-tial multiplexing with dual code-word transmis-sion on up to four transmission layers with fastrank adaptation. Additionally, an Alamouti-typetransmit-diversity technique called space-fre-quency block coding (SFBC) is supported. In theuplink multi-user (“virtual”) MIMO is used forcapacity enhancement, in which pairs of spatiallynear-orthogonal users may transmit concurrentlyon the same physical resource blocks.

EVALUATION OFNEXT-GENERATION NETWORKS

As mentioned previously, the performance of 3Gnetwork equipment and terminals was not veri-fied to the full extent when 3G was launched inearly deployments. This is one lesson learned;therefore, NGMN [1] requested performanceevaluation and field trials in parallel to standardsdevelopment. NGMN and 3GPP have initiatedthe LTE/SAE Trial Initiative (LSTI), which con-ducts trial activities and facilitates interoperabili-ty tests of LTE equipment.

Provided the metrics are meaningful and themethodology reflects realistic networks, simula-tions are a good way to compare different con-cepts and predict absolute values of networkperformance. The NGMN performance evaluationmethodology [4] is well established and allowscomparison of different standards. However, thereare still a lot of effects that are hard to foresee ormodel realistically in simulations; therefore, fieldtrials are essential to assess the performance. Also,field trials are a good proof of concept for innova-tive system-level concepts with lots of interdepen-dencies such as advanced concepts addressinginterference. Field trials also allow the calibrationof simulations and allow research and develop-ment to be focused on tackling the right issues.

Cellular networks cannot be characterizedwell by single links. Interference, resource allo-cation, and propagation environment all impactsystem performance. To capture all effects, asufficiently high number of interferers must bepresent, and multiple sectors and sites have tobe involved.

Simulations and field trials focus mainly ontechnical KPIs such as throughput and latency.However, it has to be kept in mind that the ulti-mate criterion for the mobile Internet is userexperience. This is hard to define, depends onparticular applications, and changes over time —and is beyond the scope of this article.

EASY-C: A FIELD TESTBED INDRESDEN

FIELD TESTBED AREA ANDMEASUREMENT SCENARIO

Two testbeds have been built and operated with-in the above mentioned research project EASY-C. In this article we concentrate on a physicallayer focused testbed in downtown Dresden,

Germany, using existing 2G/3G network sites ofoperators Vodafone and T-Mobile. Both opera-tors are also involved in the trials. An additionaltestbed focused on applications enabled throughLTE and advanced concepts is being set up inBerlin.

The chosen testbed location in downtownDresden covers various propagation conditions,which are of special interest for evaluation offourth-generation (4G) systems with MIMOlinks and interference conditions typical in fre-quency reuse one networks like LTE, and for thedevelopment of advanced algorithms such ascooperative MIMO:• A representative area of a medium-sized

European city• Hills in the south causing signal reflections• A river through the city causing superrefrac-

tions and tropospheric refraction• Urban areas with multistory buildings, lead-

ing to shadowing effects• An average intersite distance of 500 m

The testbed is being built in three phases. Inthe first phase, one site with three cells startedoperating in April 2008. This central site is locat-ed near Dresden’s main railway station, as shownin Fig. 1. The antenna height is 55 m. The sec-ond phase will cover a tier of sites around thiscentral site and consist of six sites with a total of18 cells. In the final stage the testbed will com-prise 10 sites with a total of 25 cells. Additionalinterferers will surround outer cells in order toemulate the interference intensity and distribu-tion of a network with three tiers of sites. Such arather extensive setup is necessary to capture alleffects of a real-world deployment.

n Figure 1. Field test area in Dresden.

Vodafone sites

Phase 1

T-Mobile sites

Phase 2 Phase 3


IEEE Communications Magazine • February 200994

At these locations new base station antennas,feeders, and microwave link equipment areinstalled.

With this three-tier network, realistic scenar-ios can be set up to investigate LTE andadvanced algorithms beyond LTE Release 8.

Furthermore, the baseline trial setup consistsof a testbed platform of base stations and mobileequipment provided by the project partner Sig-nalion. Other project partner’s equipment (i.e.,base stations, mobile, and chip prototypes) willbe inserted into the testbed for various test cases.

This infrastructure enables well defined andreproducible interference scenarios in bothuplink and downlink.

FIELD TESTBED EQUIPMENT

Figure 2 shows a test base station with a base-band unit, radio frequency (RF) hardware(including duplex filters and power amplifiers),antenna columns, and microwave backhaul units.LTE does not require GPS controlled referenceclocks for synchronization, but they are includedin this trial to investigate advanced multicellalgorithms. The sensitivity of these algorithms tosynchronization errors is one major researchtopic. The backhaul between the sites is accom-plished by low-latency microwave links. Theselinks operate in the 5 GHz frequency band andhave a maximum throughput of 300 Mb/s.

FIELD TESTBED MEASUREMENTSWithin the testbed a number of tests areplanned. For characterization of the radio envi-ronment, channel-sounding campaigns and cov-erage measurements are conducted. Theobjective of these measurements is, on one hand,the calibration of raytracing tools and the devel-opment of prediction algorithms for multicellMIMO operation in LTE-Advanced. On theother hand, cell edges can be identified: geo-graphical locations where signals from severalcells impinge with similar signal strengths.

Figure 3 shows the coverage map of the trialarea based on drive tests.

LAB RESULTSLaboratory tests with pre-standard equipmentand fading emulators have been carried out toassess the data rates and latencies that can beexpected with LTE Release 8. The results werepartly used by Alcatel-Lucent and Signalion toleverage the proof-of-concept work of LSTI.

Examples of the earlier laboratory test resultsare presented here to highlight inherent LTEcapabilities such as AMC or frequency-selectivescheduling. Further laboratory tests will be per-formed to prepare and complement the plannedfield trial activities, with particular emphasis onMIMO features.

Figure 4 depicts the physical layer cellthroughput measured from downlink single-input single-output (SISO) as a function of aver-age signal-to-noise ratio (SNR) with thefollowing configurations:• 10 MHz system bandwidth• AMC, hybrid ARQ, and multi-user schedul-

ing in downlink (DL) under control of theeNodeB

• Acknowledgment (ACK)/negative ACK(NACK) and channel quality reporting inthe uplink (UL)

• Single cell with a single user (blue curve) ortwo users (red curve) in the cell

• Full queue in the eNodeB for each user• Pedestrian A 3 km/h fading channels in

downlink and static channels in uplinkFigure 4 illustrates the capability of the AMC

to finely adjust the user data rate to the channelquality. This is achieved in the downlink byreporting channel quality indicators (CQIs) backto the eNodeB from the user equipment (UE).In this example the update rate is 1 kHz/sub-band. The peak data rate observed in Fig. 4 canbe scaled to the often quoted 88.7 Mb/s byn Figure 3. Signal coverage of the trial area based on drive tests.

RSCP [dBm] @ 10 MHz-59 --50 dBm-64 --60 dBm-69 --65 dBm-74 --70 dBm-79 --75 dBm-84 --80 dBm-89 --85 dBm-94 --90 dBm-98 --95 dBm< -99 dBm

n Figure 2. Test base station with antennas andmicrowave link at central site.



assuming 20 MHz system bandwidth, code rate1.0, and pilot/signaling overheads < 15 percentas achievable with LTE Release 8.

Figure 4 further illustrates the gain in cellthroughput obtained by applying a time- and fre-quency-selective multi-user scheduling algorithm.This gain can be quantified by relating the multi-user cell throughput to the throughput of a sin-gle user. For slowly moving user terminals, thisgain can be substantial, particularly in the lowand moderate SNR regions. It is enabled by theparticular definition of the CQI, which allowsthe full system bandwidth to be divided into sub-bands and apply the CQI reporting at the sub-band level.

In another type of measurement, the two-wayair interface latency between UE and eNodeBwas demonstrated to meet the 3GPP require-ment of below 10 ms in an unloaded cell with aprescheduled UL channel [3]. Measured laten-cies are summarized in Table 1 for different sce-narios, each using a PING application with 64bytes payload size triggered from a PC connect-ed to the UE.

While laboratory tests are a valuable meansof system characterization, they have limitationsdue to complexity and cost of laboratory equip-ment, particularly when multiple sites or anten-nas are involved, and often also are notrepresentative of real-world conditions. Thereremains, therefore, a strong motivation to carryout field trials, in particular to gain insight intothe performance of a multicellular network.

SYSTEM-LEVEL SIMULATION RESULTSThe scope of EASY-C is to prepare and supportthe standardization of LTE-Advanced and provethe enhanced concepts by field trials. The fieldtrials are accompanied by system simulations inorder to evaluate and optimize candidate algo-rithms for, say, collaborative or network MIMObefore they are implemented in the trial system.On the other hand, the accuracy of simulationresults will be investigated by comparing theseresults with measurements from the field trialsystem.

The system simulators are compliant wtih3GPP and NGMN performance verificationframeworks [4, 5]. The interference is modeledand simulated in detail. In order to avoid bound-ary effects and, hence, an overestimation of sys-tem performance, wrap around is applied. Bothinterfering and data channels are modeled by aspatial channel model. Furthermore, the simula-tions shall be realistic in terms of channel esti-mation loss and delays. In order to obtain thefull capacity of the simulated radio access net-work, full buffer services are assumed. The simu-lators are able to simulate different receive andtransmit antenna configurations with differentantenna spacings. For quick randomization ofmeasurements, the event-driven simulation issubdivided into drops in which new mobile posi-tions are randomly chosen. CQI feedback andprecoding matrix identifier (PMI) feedback aremodeled with realistic granularity and with allrelevant delays based on measured pilot SINR.The receivers are explicitly modeled and, forblock error rate (BLER) calculation, the so-

called mutual information effective SINR map-ping (MIESM) link to the system interface isapplied.

BASELINE: LTE RELEASE 8Table 2 shows exemplary results for the DL per-formance of the 2 × 2 closed-loop baseline sys-tem for two different intersite distances of 500and 1732 m, respectively. The performance ispresented as sector spectral efficiency and cellborder throughput, which is defined as the 5thpercentile of the UE throughput. The bandwidthapplied is 10 MHz. The operation point hasbeen set to 30 percent BLER for the first trans-mission. HARQ is adaptive and asynchronous;that is, retransmissions are adapted to the instan-taneous channel quality and can be postponed if,for example, the subframe foreseen for theretransmission is already occupied by otherretransmissions. The scheduler is proportionallyfair and frequency selective. Twenty-seven differ-ent modulation and coding schemes (MCSs)have been used for link adaptation and cover

n Figure 4. Downlink cell throughput vs. SNR with one or two SISO users in 10 MHz system bandwidth.

SNR (dB)5

5

Cel

l thr

ough

put

(Mb/

s)

0

10

15

20

25

0 10 15 20 25 30

Two usersSingle user

n Table 1. Measured average air interface latencies.

Scenario Latency

Single userUnloaded cellUL channel prescheduledNo channel impairments

9.9 ms

Single userUnloaded cellUL channel set-up after scheduling requestNo channel impairments

19.4 ms

Single userUnloaded cellUL channel prescheduledChannel impairments in DL

17.9 ms

Two usersCell fully loaded in DL by second userUL channel prescheduledNo channel impairments

9.8 ms



channel qualities from –6 up to 20 dB SINR.Please note that a rather pessimistic channelestimation loss model has been assumed, whichcauses the decrease of cell border throughput incase of larger intersite distances.

Table 3 shows exemplary results for the cor-responding uplink performance for single anten-na transmission and receive diversity. Path losscompensation has been applied in order to keepthe per mobile average received signal powerspectral density at the eNodeB constant. Themaximum UE transmit power is 24 dBm. Thefrequency-selective proportionally fair schedulerconsiders this maximal transmission power sothat the transmission reaches the required powerspectral density. An exception to this rule isallowed if the required power for only oneassigned resource block exceeds the maximaltransmission power. Due to the applied SC-FDMA, the scheduler assigns only adjacentresource blocks. Obviously, due to the limitedtransmit power of the mobiles, the cell borderthroughput decreases significantly for the 1732m ISD case. Different techniques such as inter-

ference coordination, or cooperative or networkMIMO may enhance cell border throughput andspectral efficiency, and will be investigated in theEASY-C project.

OPTIMIZED CODEBOOKS FOR4 × 2 SU-MIMO IN THE DOWNLINK

In this section we show exemplary results of astudy on enhancements of LTE beyond Release8.

Figure 5 shows LTE downlink results for dif-ferent antenna configurations. The results for 2× 2 and 4 × 2 are shown for precoding matricesconformant with 3GPP standard TS 36.211 [6].Additionally, in the same diagram results foroptimized codebooks are shown. These code-books are optimized for linear arrays of X-polar-ized antennas with an antenna spacing of half ofthe wavelength of the carrier frequency. Thisapproach saves up to 50 percent of feedback sig-naling load in the uplink, and at the same timeimproves cell border throughput and spectralefficiency in the downlink.

EVOLUTION OF LTE BEYOND THEINITIAL RELEASE 8: LTE-ADVANCED

With the standardization of LTE Release 8nearing completion, 3GPP has already created anew study item in order to explore candidatetechnologies for further technology evolutioncalled LTE-Advanced, which are targeted tomeet operator requirements and ITU-R’s IMT-Advanced requirements. While maintainingbackward compatibility with LTE Release 8,these ambitious performance targets include,among others [2]:• Average spectrum efficiencies of up to 3.7

b/s/Hz/cell in the DL (4 × 4) and 2.0b/s/Hz/cell in the UL (2 × 4)

• Cell edge spectrum efficiencies of 0.12b/s/Hz in the DL (4 × 4) and 0.07 b/s/Hz inthe UL (2 × 4)

• Peak data rates of up to 1 Gb/s in the DLand 500 Mb/s in the UL

• Peak spectrum efficiencies of 30 bit/s/Hz inthe DL and 15 bit/s/Hz in the UL usingantenna con-figurations of up to 8×8 in theDL and 4×4 in the UL

• Low cost of infrastructure deployments andterminals and power efficiency in the net-work and terminalsWithin the EASY-C project, the following

concepts are investigated among others thatappear to be promising to address the above-mentioned targets:• Advanced single-site MIMO• Multisector coordination/cooperation• Multisite coordination/cooperationThe schemes are illustrated in Fig. 6.

Using a high number of transmit and receiveantennas in both the DL and UL addresses thedemanding requirements for peak and averageperformances. Single-user MIMO with a largenumber of transmit and receive antennas is theenabler of high peak data rates. DL multi-userMIMO with optimized fixed beams or user-specificbeams is the key to high spectrum efficiencies.

n Figure 5. Cell border throughput vs. system spectral efficiency for LTE DLwith different antenna systems and precoding matrices.

Spectral efficiency (b/s/Hz/sector)

1.0

200

Cel

l bor

der

thro

ughp

ut (

kb/s

)

100

300

400

500

600

1.1 1.2 1.3 1.4 1.5 1.6 1.7

4 x 2, opt. codebook 2

4 x 2, opt. codebook 1

1.8 1.9 2.0

4 x 2, 36.211 codebook

2 x 2, 36.211 codebook

1 x 2

1 x 1

n Table 2. LTE Release 8 downlink baseline performance.

n Table 3. LTE Release 8 uplink baseline performance.

Antennaconfiguration

Intersitedistance (m)

Spectral efficiency(b/s/Hz)

Cell borderthroughput (kb/s)

2×2 500 1.46 345

2×2 1732 1.37 255

Antennaconfiguration

Intersitedistance (m)

Spectral efficiency(b/s/Hz)

Cell borderthroughput (kb/s)

1×2 500 0.97 295

1×2 1732 0.85 57



User-specific beams are especially suited for lowmobility where accurate channel information at thetransmitter must be available in order to createbeams with high interference suppression. Fixedbeams are suitable for moderate to high mobility,because a user’s preferred beam is directly relatedto its position in the cell and only changes on arather slow timescale. For compact X-polarizedantenna configurations, fixed beamforming canfurther be elegantly combined with diversity forlink enhancement and/or spatial multiplexing.

Multisector and multisite cooperation addition-ally boosts spectral efficiency and especially celledge performance. For instance, interference coor-dination can be used to mitigate the impact ofmultisector interference, and joint signal process-ing concepts — often referred to as networkMIMO or coordinated multipoint transmission/reception — actually allow interference to beexploited, and yield additional array and diversitygain. From a theoretical point of view, vast perfor-mance gains have been predicted for these schemesfor both UL [7] and DL [8]. However, majorresearch is still required for various practicalaspects connected to network MIMO, such as:• Synchronization of jointly processed termi-

nals in time and frequency, and detectionunder remaining synchronization offsets

• Multisector channel estimation, feedback ofchannel information to the base stations,the impact of imperfect channel estimationon network MIMO, and robust signal pro-cessing algorithms

• Performance of network MIMO and con-crete signal processing algorithms under alimited backhaul infrastructure betweencooperating base stations [9]

• Cooperative scheduling for network MIMOIn EASY-C all the above mentioned aspects

are researched, and the first laboratory and fieldtest results for LTE-Advanced technologies areexpected in 2009.

In order to optimally exploit all the variousfeatures, generalized multisite multi-user sched-ulers taking advantage of single-user, multi-user,and multisite technologies must be designed.

CONCLUSIONS AND OUTLOOKThis article shows performance results of theLTE standard based on system-level simulationsand laboratory tests for user throughput, spectralefficiency, and latency. However, it is essentialfor realistic assessment of LTE and the develop-ment of further improvements to the standard toconduct trials with multiple sectors that reflectreal-world interference conditions. Such a trialenvironment has been established within theEASY-C project. Advanced algorithms such asadvanced single-site MIMO, and multisector andmultisite cooperation are promising from a theo-retical point of view, and the established testbedwill be used to develop such concepts in detailand evaluate their real-word performance.

ACKNOWLEDGMENTThe authors acknowledge the excellent coopera-tion of all project partners within the EASY-Cproject and the support by the German FederalMinistry of Education and Research (BMBF).

REFERENCES[1] H. Akhavan et al. “Next Generation Mobile Networks

beyond HSPA & EvDo,” NGMN Alliance White Paper3.0, Dec. 2006; www.ngmn.org

[2] 3GPP TR 36.913 v. 8.0.0, “Requirements for FurtherAdvancements for E-UTRA (LTE-Advanced),” June 2008.

n Figure 6. Candidate technologies for LTE advanced.

BS site (sectorized)

MS

X-polarized antenna arrays

Advanced single-site MIMO

Multisector coordination/cooperation

Multisite coordination/cooperation

V-polarized antenna arrays



[3] 3GPP TS 25.913 v. 7.3.0, “Requirements for EvolvedUTRA (E-UTRA) and Evolved UTRAN (E-UTRAN),” Mar.2006.

[4] R. Irmer, Ed., “Next Generation Mobile Networks RadioAccess Performance Evaluation Methodology,” NGMNAlliance White Paper, June 2007; www.ngmn.org

[5] 3GPP TR 25.814 v. 7.1.0, “Physical Layer Aspects ofEvolved UTRA,” Sept. 2006.

[6] 3GPP TS 36.211 v. 8.1.0, “Physical Channels and Modu-lation,” Rel. 8, Nov. 2007.

[7] P. Marsch, S. Khattak, and G. Fettweis, “A Frameworkfor Determining Realistic Capacity Bounds for Distribut-ed Antenna Systems,” Proc. IEEE Info. Theory Wksp.,Chengdu, China, Oct. 22–26, 2006.

[8] K. M. Karakayli, G. J. Foschini, and R.A. Valenzuala,“Network Coordination for Spectrally Efficient Commu-nications in Cellular Systems,” IEEE Wireless Commun.,vol. 13, no. 4, Aug. 2006, pp. 56–61.

[9] P. Marsch and G. Fettweis, “On Multi-Cell CooperativeTransmission in Backhaul-Constrained Cellular Systems,”Annales des Télécommunications, vol. 63, no. 5–6, May2008.

BIOGRAPHIESRALF IRMER ([email protected]) received his Dipl-Ing.and Dr.-Ing. degrees from Technische Universität Dresdenin 2000 and 2005, respectively. He joined Vodafone GroupR&D in 2005, where he is working in the Beyond 3Ggroup, which is responsible for Vodafone’s strategy on LTE,WiMAX, and other technologies such as wireless mesh net-works and WLAN. Previously he worked for five years as aresearch associate at TU Dresden. He holds several patents,and has published more than 30 conference and journalpublications. He had a leading role in several research pro-jects, including WIGWAM, WINNER, and EASY-C.

HANS-PETER MAYER ([email protected])received his Ph.D. degree in physics from the University ofTübingen in 1987. He joined Alcatel-Lucent and initiallyworked on high-speed optoelectronic components. From1992 to 1995 he led the R&D activity on 1.55 µm DFB laserproducts for WDM. From 1996 to 1999 he was responsiblefor servers and databases for 3G mobile networks andearly UMTS system studies, followed by realization of thefirst UMTS and HSPA trial systems. Within Bell Labs he iscurrently responsible for the Advanced MAC departmentand LTE-Advanced projects.

ANDREAS WEBER ([email protected]) receivedDipl.-Ing. and Dr.-Ing. degrees in electrical engineeringfrom the University of Stuttgart, Germany, in 1988 and1998, respectively. From 1989 to 1995 he worked in thefield of satellite communications as a member of scientificstaff at the Institute of Communications Switching andData Technics, University of Stuttgart. In 1996 he joinedAlcatel Research & Innovation (now Alcatel-Lucent BellLabs). Currently, he is the team leader of the mobile sys-tem performance evaluation group in Alcatel-Lucent BellLabs Stuttgart.

MICHAEL SCHMIDT ([email protected]) receivedhis diploma degree in physics in 1999 and joined AlcatelResearch & Innovation (now Alcatel-Lucent Bell Labs) in2000. He worked on several research projects in diversefields such as optical signal processing and ultra-high-bit-rate optical transmission systems, as well as dynamic radioresource management and packet scheduling for 3G wire-less communications. He has authored or co-authored 24

papers in refereed journals/conferences. His currentresearch interests at Alcatel-Lucent Bell Labs includeadvanced MAC and cooperative control algorithms forLTE/LTE-Advanced.

VOLKER BRAUN ([email protected]) received hisdoctoral degree in 1997 and joined Alcatel in 1998. He iscurrently a project leader in the radio access domain atAlcatel-Lucent Bell Labs, where he has lately contributed to3G base station prototyping for the HSPA and LTE stan-dards.

MICHAEL OHM ([email protected]) receivedDipl.-Ing. and Dr.-Ing. degrees in electrical engineeringfrom the University of Stuttgart, Germany, in 2001 and2006, respectively. From 2001 to 2006 he worked at theInstitute of Telecommunications, University of Stuttgart, inthe field of telecommunications with a focus on opticalcommunications. He joined Alcatel Research & Innovation(now Alcatel-Lucent Bell Labs) in 2006, where he has beenengaged in research and standardization for the LTE sys-tem. He is a member of VDE and ITG.

NORBERT AHR ([email protected]) joined Alcatelin 1998, and Alcatel Research & Innovation (now Alcatel-Lucent Bell Labs) in 2004. He is currently working onimplementation and integration of software on 3G proto-type base stations for LTE.

CARSTEN JANDURA ([email protected]/Carsten.Jandura @vodafone.com) received a Dipl.-Ing.degree in electrical engineering from the Technical Univer-sity of Dresden in 1994. Since 1995 he has been with Man-nesmann Mobilfunk GmbH and later Vodafone D2 GmbH.His special topic is network optimization for GSM andUMTS networks with a focus on field measurement andperformance measurement evaluation. Since 2005 he iswith the Vodafone Chair Mobile Communication Systems.

PATRICK MARSCH ([email protected]) received hisDipl.-Ing. degree from Technische Universität Dresden in2004, after completing an apprenticeship at Siemens AGand studying at TU Dresden and McGill University, Mon-tréal, Canada. After an internship with Philips ResearchEast Asia in Shanghai, P.R. China, he joined the VodafoneChair in 2005, where he is focusing on multicell coopera-tive signal processing schemes under a constrained back-haul. Since April 2007 he has been the technical projectcoordinator of EASY-C.

GERHARD FETTWEIS ([email protected]) earned his Dipl.-Ing. (1986) and Ph.D. (1990) degrees from Aachen University ofTechnology (RWTH), Germany. From 1990 to 1991 he was a visit-ing scientist at the IBM Almaden Research Center, San Jose, Califor-nia, working on signal processing for disk drives. From 1991 to1994 he was with TCSI Inc., Berkeley, California, responsible for sig-nal processor development. Since 1994 he holds the VodafoneChair at TU Dresden. He is coordinating the EASY-C research pro-ject.

ANDRÉ ZOCH ([email protected]) received his Dipl.-Ing. and Dr.-Ing. degrees in electrical engineering from theTechnical University of Dresden, Germany, in 1998 and2004, respectively. From 1998 to 2004 he worked with theVodafone Chair Mobile Communications Systems at theTechnical University of Dresden with a focus on UMTSreceiver design and implementation. He is co-founder ofSignalion GmbH and has with Signalion since 2004 in thefield of prototyping wireless communication systems.


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Multisite Field Trial for LTE and Advanced Concepts