Engineering in the Wireless Telecommunications Industry

Curt Gervelis – MSEE4 – 27 – 2011

Curt Gervelis - Introduction and Background, “My Path Through 25 Years of Wireless Technology Evolution”

Education:

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

– University of Cincinnati 1983 – 1986 MS Electrical & Computer Engineering.

Curt Gervelis - Introduction and Background, “My Path Through 25 Years of Wireless Technology Evolution”

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

– AT&T Wireless (NYC Region) Sr. Systems Eng. Mgr., 1989 – 1995, Technology 1G AMPS 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

Curt Gervelis - Introduction and Background, “My Path Through 25 Years of Wireless Technology Evolution”

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

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

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.

Cellular Wireless Technology Evolution:

2G:- GSM / 3GPP StandardsGlobal System for Mobile Communications (GSM). GSM is the European standard for digital cellular systems operating in the 900 MHz band. This technology was developed out of the need for increased service capacity due to the analog systems limited growth. This technology offers international roaming, high speech quality, increased security, and the ability to develop advanced systems features.

Cellular Wireless Technology Evolution:

2G- CDMAOne, IS-95 / 3Gpp2 StandardsCode Division Multiple Access (CDMA). CDMA is an alternative digital cellular standard developed in the United States. CDMA utilizes the IS-95 standard and is implemented as the next generation for cellular systems. The CDMA system coexists with the current analog system.

Cellular Wireless Technology Evolution:

2G- AMPS (D-AMPS, IS-54 and IS-136) TDMAD-AMPS. Digital AMPS system, also called NADC, North American Digital Cellular is the digital standard for cellular systems developed for use in the United States. Rather than develop a completely new standard the AMPS standard was developed into the D-AMPS digital standard. This was done to quickly provide a means to expand the existing analog systems that were growing at a rapid pace. NADC is designed to coexist with current cellular systems and relies on both the IS-54 and IS-136 standards.

Cellular Wireless Technology Evolution:

2G - iDENIntegrated Dispatch Enhanced Network (iDEN) is the name for an alternative form of cellular communication which operates in the SMR band just adjacent to the cellular frequency band. IDEN is a blend of wireless interconnect and dispatch services which makes it very unique as compared to existing cellular and PCS systems. IDEN utilizes a digital radio format called QAM and is a derivative of GSM for the rest of the system with the exception of the radio link.

Cellular Wireless Technology 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)

Cellular Wireless Technology 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

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

Wireless Technologies Specifications:

Standard Family Primary Use

Radio Tech Downlink (Mbit/s)

Uplink (Mbit/s)

Notes

WiMAX 802.16Mobile Internet

MIMO-SOFDMA

128 (in 20MHz bandwidth)

56 (in 20MHz bandwidth)

WiMAX update IEEE 802.16m expected to offer peak rates of at least 1 Gbit/s fixed speeds and 100Mbit/s to mobile users.

LTE UMTS/4GSM

General 4G

OFDMA/MIMO/SC-FDMA

100 (in 20MHz bandwidth)

50 (in 20 MHz bandwidth)

LTE-Advanced update expected to offer peak rates up to 1 Gbit/s fixed speeds and 100 Mb/s to mobile users.

Wireless System Design – New “Greenfield” Implementation

MSC

BSC

BSC

BTS

BTS

BTS

BTS

BTS

BTS

SMS-SCHLR

Public Telephon eNetwork

MSC

Wireless System Design – New “Greenfield” Implementation

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

Wireless System Design – New “Greenfield” Implementation

RF Network / RAN Design (process and requirements):1.) Marketing Data:

- Mobile Services (Voice / Data)- Coverage Area- Estimated number of subscribers- Estimated subscriber growth rate

Wireless System Design – New “Greenfield” Implementation

RF Network / RAN Design (process and requirements):

2.) Technology:

- 1G AMPS

- 2G GSM / CDMA / TDMA

- 3G GPRS / CDMA2000

- 4G LTE / WiMax

Wireless System Design – New “Greenfield” Implementation

RF Network / RAN Design (process and requirements):

- Technology bandwidth requirements (Cellular / SMR and PCS)

- Spectrum characteristics (700 Mhz verses 1900 Mhz)

Wireless System Design – New “Greenfield” Implementation

RF Network / RAN Design (process and requirements):

3.) Cell site design:

- Omni

- 3 Sector

- 6 Sector

Wireless System Design – New “Greenfield” Implementation

Reference Table 4.11 AMPS RF Design Guideline

Wireless System Design – New “Greenfield” Implementation

RF Network / RAN Design (process and requirements):4.) Cell Site Link Budget:- Determine cell maximum propagation radius- RF Engineering “itemized accounting” of cell sites transmit and receive energy during operation.

Wireless System Design – New “Greenfield” Implementation

Information Modulation Transmitter(Power Amplifier)

Feedline

Antenna

Tx Filter Rx Filter Pre-Amplifier Demodulation Information

Antenna

FeedlinePropagation

Trasnmitter Receiver

Wireless System Design – New “Greenfield” Implementation

Reference RF Forward Link Budget Table Reference RF Reverse Link Budget Table

Wireless System Design – New “Greenfield” Implementation

RF Propagation Modeling:- Free space path loss is usually the reference point for all the path loss models employed. Each propagation model points out that it more accurately predicts the attenuation experienced by the signal over that of free space. The equation that is used for determining free space path 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 , km fc = transmit frequency, MHz Lf = free space path loss, dB

Wireless System Design – New “Greenfield” Implementation

RF Propagation Modeling:

Free Space Path Loss:

The baseline assumptions involved with the table listed below are distances in km and a frequency of 880 MHz.Distance (km) Pathloss (dB)

1.0 91.292.0 97.313.0 100.834.0 103.335.0 105.27

Wireless System Design – New “Greenfield” Implementation

RF Propagation Modeling:

Hata is a standard path loss model employed in cellular, ESMR and 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

Wireless System Design – New “Greenfield” Implementation

RF Propagation Modeling: 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.

Wireless System Design – New “Greenfield” Implementation

Cost231 model:

The Cost231 model is composed of three basic components.1) Free space loss2) Roof to Street Diffraction Loss and Scatter Loss3) Multiscreen Loss

Lc = Lf + LRTS + Lms Lf when LRTS + Lms <=0

Where Lf = free space loss LRTS = rooftop to street diffraction and scatter loss Lms =multiscreen loss

Wireless System Design – New “Greenfield” Implementation

RF Network / RAN Design (process and requirements):

5.) Frequency Planning:

- N=3

- N=4

- N=7

- N=12

Wireless System Design – New “Greenfield” Implementation

Reference Figures 4.14 and 4.15 Frequency Planning Diagrams

Wireless System Design – New “Greenfield” Implementation

RF Network / RAN Design (process and requirements):

6.) Capacity Requirements:

- Number of Subscribers / coverage area- Number busy hour calls / subscriber- Call holding times- Estimated radio channels per site / sector

Wireless System Design – New “Greenfield” Implementation

RF Network / RAN Design (process and requirements):

At this point in the process we have a theoretical design of the RF network.

Wireless System Design – New “Greenfield” Implementation

RF Design Implementation:

1.) Cell site acquisition:

- Issue search rings to real estate department

- Acquire candidate sites according to Engineering guidelines

Wireless System Design – New “Greenfield” Implementation

RF Design Implementation:

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

decision.

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

Wireless System Design – New “Greenfield” Implementation

RF Design Implementation:

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.

Wireless System Design – New “Greenfield” Implementation

RF Design Implementation:

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

Wireless System Design – New “Greenfield” Implementation

Core Network Design:

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

- Interconnection facilities

- Environmentals (power plant, HVAC, Fire Suppression)

Wireless System Design – New “Greenfield” Implementation

Core Network Design:

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)

Wireless System Design – New “Greenfield” Implementation

Core Network Design:

2.) Equipment configuration and dimensioning:

- Aux. systems (SMSC, VM, OTA, SS7 Data)

Wireless System Design – New “Greenfield” Implementation

Interconnection Design:

1.) Cell Site Back-haul

2.) Intra-network connectivity

3.) Inter-network connectivity (PSTN / roaming mobile networks / internet)

Core Network Evolution:

Core network evolution:

1.) Circuit based core infrastructure

2.) Hybrid (Circuit / Packet) core infrastructure.

3.) Packet based core infrastructure

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 new sites

Engineering Roles in the Wireless 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

Engineering Roles in the Wireless Industry:

Systems Engineer:

- Responsible for individual systems or groups of related systems 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, external networks (roaming),

Engineering Roles in the Wireless 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)

Engineering Roles in the Wireless Industry:

Equipment Engineer:

- Responsible for the installation and maintenance of cell sites, switches, and auxiliary equipment in the network.

Facilities / Transport Engineer:

- Responsible for the maintenance and management of the interconnection network (Cell site back-haul, inter and intra network)

Future Opportunities / Industry Trends:

4G LTE Networks and Technology Machine to Machine (M2M) technologies Self Organizing Networks (SON’s) White Space Technologies / Networks

Recommendations:

Gain familiarity with industry standards bodies and standards (3GPP / 3GPP2 / IEEE)

Major industry companies (Vzw / ATT / Sprint / T-mobile)

Statistics and process modeling is in demand Gain business skills (project planning,

finance and accounting)