Engineering in the Wireless

7/28/2019 Engineering in the Wireless

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Engineering in the WirelessTelecommunications IndustryCurt Gervelis MSEE

4 27 2011


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Curt Gervelis - Introduction andBackground, My Path Through 25 Years ofWireless Technology Evolution

Education:

Mount Union College 1979 1983, BA Physics & Math, Minor Computer Science.

University of Cincinnati 1983 1986 MS Electrical & Computer Engineering.


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Industry Experience: Motorola, Systems Eng. 1987 89, Technology 1G AMPS

AT&T Wireless (NYC Region) Sr. Systems Eng. Mgr., 1989 1995, Technology 1GAMPS and IS136 Digital TDMA

Omnipoint Lead Network Eng., 1996 -1997, Technology 2G GSM

Telecorp PCS Director Network Eng. 1997-2000, Technology 1G TDMA PCS

Nextel International Sr. Operations Mgr. 2001 2003, Technology Motorola iDen

(GSM variant)

MetroPCS 2005 2009, Engineering Manager, Technology 2G + CDMA

Intellectual Ventures Sr. Staff Engineer, 2010 , Technology 2G, 3G, 4G


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Professional Development:

- Two industry publications by McGraw-Hill:Cellular System Design and Optimization, McGraw-Hill Company, and ISBN

0-07-059273-X.

Wireless Network Performance Handbook, McGraw-Hill Company, and ISBN

0-07-140655-7

.- Industry Associations:

IEEE and IEEE Communications Society


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Communication History:

1844 Samuel Morse invents the telegraph 1876 Alexander Bell invents the telephone

1901- Marconi sends morse code using a radio 1931- First US television transmission takes place 1946- AT&T offers mobile phone service (non-cellular) 1953- First Microwave network installed 1956- Transatlantic cable constructed 1977 Bell labs transmits TV signals on optical fibers 1983 Cellular Communication was fostering a

communications revolution


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Cellular Wireless Technology

Evolution:

1G:

- AMPS (AMPS / TACS / ETACS)

Advanced Mobile Phone System (AMPS) standard. AMPS is

the cellular standard that was developed for use in North

America. This type of system operates in the 800 Mhz

frequency band. AMPS systems have also been deployed in

South America, Asia, and Russia.


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Evolution:

2G:

- GSM / 3GPP Standards

Global System for Mobile Communications (GSM). GSM isthe European standard for digital cellular systems operatingin the 900 MHz band. This technology was developed out ofthe need for increased service capacity due to the analogsystems limited growth. This technology offers internationalroaming, high speech quality, increased security, and the

ability to develop advanced systems features.


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Evolution:

2G

- CDMAOne, IS-95 / 3Gpp2 Standards

Code Division Multiple Access (CDMA). CDMA isan alternative digital cellular standard developed inthe United States. CDMA utilizes the IS-95 standardand is implemented as the next generation for

cellular systems. The CDMA system coexists withthe current analog system.


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Evolution:

2G

- AMPS (D-AMPS, IS-54 and IS-136) TDMA

D-AMPS. Digital AMPS system, also called NADC, NorthAmerican Digital Cellular is the digital standard for cellularsystems developed for use in the United States. Rather thandevelop a completely new standard the AMPS standard wasdeveloped into the D-AMPS digital standard. This was done toquickly provide a means to expand the existing analog systems

that were growing at a rapid pace. NADC is designed tocoexist with current cellular systems and relies on both the IS-54 and IS-136 standards.


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Evolution:

2G

- iDEN

Integrated Dispatch Enhanced Network (iDEN) is the name foran alternative form of cellular communication which operates inthe SMR band just adjacent to the cellular frequency band.IDEN is a blend of wireless interconnect and dispatch serviceswhich makes it very unique as compared to existing cellularand PCS systems. IDEN utilizes a digital radio format called

QAM and is a derivative of GSM for the rest of the system withthe exception of the radio link.


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Evolution:

2G Transitional (2.5 G, 2.75 G)

- GSM / 3GPP (GPRS / EDGE)- CDMA / 3GPP2 (CDMA2000 1xRTT)

- WiDEN

3G (IMT-2000):

- 3GPP (UMTS / UTRAN / WCDMA)

- 3GPP2 (CDMA2000 1xEVDO, IS-856)


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Evolution:

3G Transitional:

- 3GPP (HSPA / HSPA +)- 3GPP2 (EVDO Rev. A and Rev. B)

- IEEE Mobile WiMax, IS-802.16e

4G IMT - Advanced:

- 3GPP LTE Advanced

- IEEE Mobile WiMax, IS-802.16m


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Wireless Technologies Specifications:

IS-136 IS-95 DCS1800(GSM)

DCS1900

(GSM)IS661

Base Tx MHz 1930-1990 1930-1990 1805-1880 1930-1990 1930-1990

Base Rx MHz 1850-1910 1850-1910 1710-1785 1850-1910 1850-1910

Multiple Access Method TDMA CDMA TDMA TDMA TDD

Modulation Pi/4DPSK QPSK 0.3 GMSK 0.3 GMSK QPSK

Radio Channel Spacing 30kHz 1.25MHz 200kHz 200kHz 5MHz

Users/Channel 3 64 8 8 64

Number Channels 166/332/498 4-12 325 25/50/75 2-6

CODEC ACELP/VCELP

CELP RELP-LTP RELP-LTP CELP

Spectrum Allocation 10/20/30Mhz 10/20/30Mhz 150MHz 10/20/30Mhz 10/20/30Mhz


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Wireless Technologies Specifications:

Standard FamilyPrimary

UseRadio Tech

Downlink(Mbit/s)

Uplink(Mbit/s)

Notes

WiMAX 802.16MobileInternet

MIMO-SOFDMA

128 (in20MHz

bandwidth)

56 (in20MHz

bandwidth)

WiMAX updateIEEE 802.16m expected tooffer peak rates of at least1 Gbit/s fixed speeds and100Mbit/s to mobile users.

LTEUMTS/4GSM

General4G

OFDMA/MIMO/SC-FDMA

100 (in20MHz

bandwidth)

50 (in 20MHz

bandwidth)

LTE-Advanced updateexpected to offer peakrates up to 1 Gbit/s fixedspeeds and 100 Mb/s tomobile users.
http://en.wikipedia.org/wiki/WiMAXhttp://en.wikipedia.org/wiki/802.16http://en.wikipedia.org/wiki/MIMOhttp://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiple_accesshttp://en.wikipedia.org/wiki/IEEE_802.16mhttp://en.wikipedia.org/wiki/3GPP_Long_Term_Evolutionhttp://en.wikipedia.org/wiki/OFDMAhttp://en.wikipedia.org/wiki/MIMOhttp://en.wikipedia.org/wiki/SC-FDMAhttp://en.wikipedia.org/wiki/LTE_Advancedhttp://en.wikipedia.org/wiki/LTE_Advancedhttp://en.wikipedia.org/wiki/SC-FDMAhttp://en.wikipedia.org/wiki/MIMOhttp://en.wikipedia.org/wiki/OFDMAhttp://en.wikipedia.org/wiki/3GPP_Long_Term_Evolutionhttp://en.wikipedia.org/wiki/IEEE_802.16mhttp://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiple_accesshttp://en.wikipedia.org/wiki/MIMOhttp://en.wikipedia.org/wiki/802.16http://en.wikipedia.org/wiki/WiMAX


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Wireless System Design New

Greenfield Implementation

MSC

BSC

BSC

BTS

BTS

BTS

BTS

BTS

BTS

SMS-SCHLR

Public Telephon e

Network

MSC


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Wireless Greenfield System Design:

1.) Radio Access Network (RAN) is first step and

highest priority in design process.

2.) Core Network design for support of mobility and

interface to external networks including the Public

Switched Telephone Network (PSTN)

3.) Interconnection Network for cell site back-haul

and intra-network connections


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RF Network / RAN Design (process andrequirements):

1.) Marketing Data:

- Mobile Services (Voice / Data)

- Coverage Area

- Estimated number of subscribers- Estimated subscriber growth rate


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RF Network / RAN Design (process and

requirements):2.) Technology:

- 1G AMPS

- 2G GSM / CDMA / TDMA

- 3G GPRS / CDMA2000

- 4G LTE / WiMax


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requirements):

- Technology bandwidth requirements

(Cellular / SMR and PCS)

- Spectrum characteristics (700 Mhz verses

1900 Mhz)


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requirements):3.) Cell site design:

- Omni

- 3 Sector

- 6 Sector


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Reference Table 4.11 AMPS RF Design

Guideline


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4.) Cell Site Link Budget:

- Determine cell maximum propagationradius

- RF Engineering itemized accounting ofcell sites transmit and receive energyduring operation.


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In formation Modulation Transmitter(Power Amplifier)

Feedline

Antenna

Tx Filter Rx Filter Pre-Amplifier Demodulation Information

Antenna

FeedlinePropagation

Trasnmitter Receiver


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Reference RF Forward Link Budget Table

Reference RF Reverse Link Budget Table


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RF Propagation Modeling:- Free space path loss is usually the reference point for all the pathloss models employed. Each propagation model points out that it more

accurately predicts the attenuation experienced by the signal over thatof free space. The equation that is used for determining free spacepath loss is based on 1/R2 or 20 dB per decade path loss.

Lf = 32.4 + 20 log10 R + 20 log10 fc

Where R = distance from cell site , kmfc = transmit frequency, MHz

Lf = free space path loss, dB


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RF Propagation Modeling:

Free Space Path Loss:

The baseline assumptions involved with the table listed below aredistances in km and a frequency of 880 MHz.

Distance (km) Pathloss (dB)

1.0 91.29

2.0 97.31

3.0 100.83

4.0 103.33

5.0 105.27


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Hata is a standard path loss model employed in cellular, ESMRand PCS or some variant of it.

LH = 69.55 + 26.16 log10 fc - 13.82 log10 hb - a (hm) +(44.9-6.55 log10 hb)log10 R

Where LH = path loss for Hata Model

hb = Base station antenna height ,m

hm = Mobile or portable antenna height ,m


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The Cost231 Walfish/Ikegami propagation model[40] is used for estimating the pathloss in an urban

environment for cellular, ESMR and PCS

communication. The Cost231 model is a

combination of empirical and deterministic modeling

for estimating the path loss in an urban environment

over the frequency range of 800 to 2000 MHz.


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Cost231 model:

The Cost231 model is composed of three basic components.

1) Free space loss2) Roof to Street Diffraction Loss and Scatter Loss

3) Multiscreen Loss

Lc = Lf + LRTS + Lms

Lf when LRTS + Lms


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requirements):

5.) Frequency Planning:

- N=3

- N=4

- N=7

- N=12


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Reference Figures 4.14 and 4.15 Frequency

Planning Diagrams


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6.) Capacity Requirements:

- Number of Subscribers / coverage area

- Number busy hour calls / subscriber- Call holding times

- Estimated radio channels per site / sector


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requirements):

At this point in the process we have a

theoretical design of the RF network.


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RF Design Implementation:

1.) Cell site acquisition:

- Issue search rings to real estate

department

- Acquire candidate sites according toEngineering guidelines


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2.) RF Engineering sets up test equipment to mimica live cell site and conducts field tests to qualifythe sites performance for a pass / decline

decision.

3.) Facilities Engineering builds the site accordingRF, Manufacture, and Zoning requirements.


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4.) Network Engineering designs and

implements cell site back-haul facilities

(T-1 circuits, microwave links, etc.) to connect

site to the mobile switching network.


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5.) Perform cell site integration for all cells to

interoperate within the RF network.

- Intra-cell Handoff settings and testing

- Inter-cell Handoff settings and testing- Interference analysis


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Core Network Design:

1.) Switching Office Location and Design(similar to a data center design)

- Interconnection facilities

- Environmentals (power plant, HVAC,

Fire Suppression)


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2.) Equipment configuration and dimensioning:

- Mobile switch (cpu capacity/s, mobile ports.

wireline ports, packet data ports, mobile

services)

- HLR / AAA / HSS subscriber Database

dimensioning (sub count, service transaction

rates)


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2.) Equipment configuration anddimensioning:

- Aux. systems (SMSC, VM, OTA,

SS7 Data)


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Interconnection Design:

1.) Cell Site Back-haul2.) Intra-network connectivity

3.) Inter-network connectivity (PSTN /

roaming mobile networks / internet)


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Core Network Evolution:

Core network evolution:

1.) Circuit based core infrastructure2.) Hybrid (Circuit / Packet) core

infrastructure.

3.) Packet based core infrastructure


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Engineering Roles in the Wireless

Industry:

RF Engineer

- Responsible for the macro and micro cell planning and designs- Responsible for the RF testing and validation

- Perform RF network troubleshooting and optimization

- Frequency management of the network

- Inter system coordination along bordering networks

- Regulatory (FCC) and aeronautical compliance (FAA) for newsites


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Industry:

Network Engineering:

- Responsible for the architectural engineering of the network

growth

- Evaluating new network designs

- Performing network troubleshooting

- Plans the switch dimensioning, module growth and when a

new switch is needed for the network with its proposed

location.- Responsible for the voice and data network dimensioning and

all value added systems that are adjuncts to the voice network


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Industry:

Systems Engineer:

- Responsible for individual systems or groups of relatedsystems such as subscriber database nodes (HLR / AAA /

HSS), data systems (SMS / MMS / PDSN)

- Coordinate systems changes and upgrades with other

parts of the network (RF RAN, Core Network, externalnetworks (roaming),


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Industry:

Traffic Engineer:

- Responsible for the channel capacity dimensioning

of the RF network (RAN) and the core network as

well as interconnections to external networks.

- Perform optimal routing and resource allocation

planning for budgeting and network optimization.

- Use of Erlang B (RAN), Erlang C and Poisson

models (Core / Wireline)


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Industry:

Equipment Engineer:

- Responsible for the installation and maintenance ofcell sites, switches, and auxiliary equipment in thenetwork.

Facilities / Transport Engineer:

- Responsible for the maintenance and managementof the interconnection network (Cell site back-haul,

inter and intra network)


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Future Opportunities / Industry Trends:

4G LTE Networks and Technology

Machine to Machine (M2M) technologies Self Organizing Networks (SONs)

White Space Technologies / Networks


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Recommendations:

Gain familiarity with industry standardsbodies and standards (3GPP / 3GPP2 /

IEEE)Major industry companies (Vzw / ATT / Sprint

/ T-mobile) Statistics and process modeling is in demandGain business skills (project planning,

finance and accounting)

Engineering in the Wireless

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