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MAITT Summer Workshop 2004MAITT Summer Workshop 2004

An Introduction to 3G Cellular and the An Introduction to 3G Cellular and the IEEE 802 Wireless TechnologiesIEEE 802 Wireless Technologies

G. Mullett – Co-Pi (Wireless)

National Center for Telecommunications Technologies July 19, 2004




Goals of this sessionGoals of this session

• Provide an overview of the 3G cellular system and its impact on wireless data

• Provide an overview/status report of the various IEEE 802 wireless technologies:– IEEE 802.11/Wireless LANs– IEEE 802.15/Wireless PANs– IEEE 802.16/Wireless MANs– IEEE 802.20/Mobile Broadband Wireless

Networks

• Attempt to provide a picture of the integrated wireless infrastructure of the future




3G Cellular and beyond3G Cellular and beyond

• To fully appreciate 3G cellular capabilities, it will be helpful for us to take a quick look at the evolution of cellular technology

• We will then examine the characteristics of 3G cellular and its two most popular implementations – UMTS and cdma2000

• Without a chance to catch our breath, we will introduce the general characteristics of proposed 4G wireless networks

• We will return to 3G/4G wireless after introducing the IEEE 802 wireless technologies




A short history of cellular A short history of cellular technologytechnology

• Device and radio technology had evolved enough that a limited mobile radio-telephone service was introduced in 1946 by AT&T and Southwestern Bell

• The cellular telephone concept had been first put forward in the late 1940s but was not implemented until much later on when the early mobile radio telephone systems became fully saturated with users and were unable to meet public demand




A short history of cellular A short history of cellular technology (cont.)technology (cont.)

• Finally, after many delays, commercial Advanced Mobile Phone System (AMPS) cellular phone service commenced operation in the US in 1983

• The AMPS system is based on an analog modulation (FM) scheme and is designed to carry only voice traffic

• The rest of the world was not waiting for the US to create a universal standard and therefore several different systems evolved in other parts of the world





• It is interesting to note, that at the time, there were no universal frequency allocations for cellular service and for that reason the vast majority of the various early AMPS systems deployed world wide were not compatible with one another

• These first analog systems are known as first generation (1G) cellular technology

• Support for the AMPS system is due to be phased out in the US in the year 2007





• Shortly after the introduction of AMPS technology, the European countries began working together to develop a pan-European cellular system

• In 1990, the first phase of the Global System for Mobile communications or GSM was adopted and commercial operation commenced soon thereafter in late 1992

• The wireless system chosen utilized digital modulation technology and was thus known as a second generation or 2G cellular phone system





• In the United States, cellular operators overlaid a modified version of the AMPS system, known as D-AMPS, on existing AMPS systems to increase capacity

• Eventually, a true 2G TDMA system was developed for use on the 800 MHz cellular and then the 1900 MHz personal communications system (PCS) bands

• This 2G cellular technology system became known as North American TDMA and still enjoys some popularity





• During the early 1990s, a totally new digital technology known as code division multiple access or CDMA was developed by Qualcomm Corporation

• The first commercial deployment of CDMA was in Hong Kong during 1995

• CDMA technology has caught on rapidly in the US and eventually will become the dominant transmission technology for 3G and 4G cellular systems as wireless evolves




Defining 2G cellular technologyDefining 2G cellular technology

• Recall that 1G cellular systems used analog modulation techniques to transmit the subscriber’s voice over the traffic channel

• All subsequent generations of cellular systems convert a user’s voice from an analog signal to digital form and then use some form of digital modulation to transmit the digital encoding of the voice message




2G characteristics2G characteristics

• This conversion to a digital format is extremely important since it usually results in the ability of the cellular system to accommodate more than one user at a time over the same communications link

• This ability is usually referred to as multiplexing or “multiple access”

• The two most common forms of 2G cellular multiplexing techniques are known as time division multiple access (TDMA) and code division multiple access (CDMA)




2G characteristics (cont.)2G characteristics (cont.)

• 2G cellular systems use digital modulation techniques to send digital control messages

• As a further consequence of using digital encoding for the user traffic, digital encryption may be employed that provides both security and privacy for the mobile network subscribers – this was not the case for 1G systems

• TDMA systems (GSM, North American TDMA, and Personal Digital Communications (PDC)) all use timeslots to allocate a fixed periodic time when the subscriber has exclusive use of a particular radio channel (similar to T1 technology used in telephony)




A quick look at typicalA quick look at typical cellular system architecture cellular system architecture

HLR – Home Location Register

VLR – Visitor Location Register

MSC – Mobile Switching Center

AUC – Authentication Register

BSC – Base Station Controller

RBS – Radio Base Station

MS – Mobile Station

EIR – Equipment Identification Register

ILR – Interworking Location Register

Source: Ericsson




Cdma technologyCdma technology

• CDMA or spread spectrum systems use special codes at both the transmitter and receiver to encode the signal and thus allow communications between the two devices. However, other receivers see the signals as noise

• Therefore, using CDMA technology, many communications links may be established using the same frequency spectrum in the same geographic location if unique codes are available for use by transmitter/ receiver pairs




Digital data over 2G systemsDigital data over 2G systems

• Circuit switched data transmission over 1G cellular systems was possible using modems but limited to very low speeds

• Cellular Digital Packet Data (CDPD) was developed in the early 1990s as a wireless packet data network that could be overlaid on an AMPS network

• 2G systems were designed with data services in mind. 2G GSM and CDMA systems supported low speed packet data service




2.5G systems2.5G systems

• Driven by the popularity of the Internet, cellular operators adopted a migration path to provide high-speed packet data service over their cellular systems

• 2.5G cellular systems would provide data transfer rates of approximately 64-120 kbps (referred to as high-speed at the time)

• GSM would employ a technique known as generic packet radio service or GPRS. Basically, this system would assign additional timeslots from a GSM TDMA frame to a user thus increasing the user’s bandwidth




2.5G systems (cont.)2.5G systems (cont.)

• 2.5G CDMA cellular systems also provided higher data transfer rates by allowing a user to be allocated more than one radio link (actually up to a maximum of 8)

• In both cases, the changes necessary to accomplish the up-grade to 2.5G systems was basically a software up-grade and the addition of equipment that could interface with the IP network




Present status of cellularPresent status of cellular• GSM – Approximately 72.3% of the world’s

cellular customers. 685 networks, 592 operators, 203 countries, and over 1.1 billion subscribers

• CDMA – Approximately 13.8% of the world’s cellular telephones. 207 networks, 113 operators, 50 countries, and over 200 million subscribers

• NA-TDMA – Approximately 7.36% or 107 million subscribers

• PDC – Approximately 4.22% or 61 million users




3G systems3G systems

• The cellular industry, facilitated by the International Telecommunications Union (ITU), has developed characteristics and standards for what is known as 3G cellular

• The IMT-2000 forum was convened to address the mobile telecommunication needs of the 21st century

• 3G system characteristics call for high-speed data access of packet networks and global roaming




3G system characteristics3G system characteristics(cell hierarchy)(cell hierarchy)




3G system characteristics (cont.)3G system characteristics (cont.)

Cell Type Mega Cell Macro Cell Micro Cell Pico Cell

Cell Radius 100-500 km

<=35 km <=1 km <=50 m

Operating Environment

Global Suburban (low density)

Urban(high density)

In-building

Installation Type

Satellites On the top of a building or tower

On a lamp post or the side of a building

Inside a building

Mobile Speed (km/h)

<=500 <=100 <=10

Data Rate N/A 144 kbps 384 kbps 2 Mbps




3G cellular systems3G cellular systems

• Several potential 3G radio transmission technology (RTT) schemes were submitted to the ITU for consideration

• At this time, two systems have been embraced for the delivery of 3G cellular:– GSM/GPRS/EDGE which evolves to UMTS– Cdma2000 1x which evolves to cdma2000

1xEV-DO and eventually cdma2000 1xEV-DV

• What about NA-TDMA and PDC? They will not support 3G service. Either UMTS or cdma2000 will have to be overlaid




Status of 3G cellular systemsStatus of 3G cellular systems

• One may go to www.3gamericas.org and www.cdg.org to see the most up-to-date statistics about the migration of GSM and CDMA towards 3G capability

• It is happening as I speak. The Verizon Wireless network offers 144 kbps over their entire footprint and they have started to deploy cdma2000 1xEV-DO

• Other service providers have started to advertise their GSM networks (AT&T Wireless and Cingular) with GPRS and EDGE technology




3G cellular services3G cellular services

• Web access, Laptop or PDA wireless data access, and Push-to-Talk service

• Text messaging – Short Message Service or SMS

• Multimedia Messaging Service or MMS• Phones with video cameras and still

cameras (Reported to be outselling digital cameras!)

• Ring tones and Games• I call everything but the first applications -

generational wireless applications




3G cellular services (cont.)3G cellular services (cont.)

• Some statistics (from InStat/MDR):– In the US, 54% of mobile customers are using

one or more data services over their phones (i.e. SMS, Internet access, ring tones, and games)

– Wireless data customers use 42% more voice minutes than non-data customers and spend 19% more on their wireless bill per month

• Also, predictions are for a more than five-fold increase in voice traffic and that cellular video traffic will increase to 7.7 Mbit/user/day and cellular packet data to 6.8 Mbit/user/day from 2002 to 2010




Cellular traffic predictionsCellular traffic predictions

From DrKW Equity Research




Status of 3G/UMTSStatus of 3G/UMTS cellular systems cellular systems

• Universal Mobile Telephone Service (UMTS) is the next evolutionary step for GSM networks as they evolve to true 3G networks that utilize wideband CDMA (WCDMA) technology

• Worldwide, UMTS 3G cellular networks (IP based) presently support over 5 million users with predictions of:– 10-15 million users by the end of 2004 – 125-150 million users by the end of 2007




What about 4G?What about 4G?

• No sooner has the cellular industry started to build out 3G then it has started to standardize 4G

• 4G is going to provide high-speed access to an all-IP network allowing the delivery of multimedia content in a seamless and ubiquitous fashion

• The characteristics of 4G have been taking shape with the cellular industry even putting an anticipated time table into place (starting with the preliminary adoption of standards in 2007)




Typical 4G characteristicsTypical 4G characteristics

Source: IEEE Wireless Communications




4G characteristics (cont.)4G characteristics (cont.)

• 4G networks will have to support all of the traditional cellular operations such as mobility management and radio resource and power management, as well as:– Support for vertical handoffs between

heterogeneous networks (i.e. from cellular to IEEE 802.11 (WLAN), etc)

– Support for multiple-hop networks– Support for reconfigurable or cognitive

networks




4G timetable4G timetable

Source: IEEE Wireless Communications




IEEE 802 wireless technologies IEEE 802 wireless technologies

• Today, most of us have been exposed to wireless LANs

• Many have deployed wireless LANs in their homes and apartments to maximize the use of high-speed broadband access (i.e. cable modem or ADSL)

• The IEEE is the organization in charge of the standards for this type of technology (see www.ieee.org)

• In particular, wireless LAN standards are covered by IEEE 802.11




Wireless LANs/IEEE 802.11Wireless LANs/IEEE 802.11

• The initial IEEE 802.11 standard was finalized in June of 1997

• The technology has a much longer history that can be traced back to 1971 with the implementation of ALOHA-Net at the University of Hawaii

• Early proprietary systems used the lower frequency unlicensed ISM bands (902-928 MHz) opened up by the FCC in 1985

• Standardization efforts started in 1991




Wireless LANs/IEEE 802.11 Wireless LANs/IEEE 802.11 (cont.)(cont.)

• The initial standard called for the use of the 2.4 GHz unlicensed ISM band with data transfer rates of 1 or 2 Mbps using spread spectrum modulation

• This initial data rate did not help user adoption in the early going since most LAN users were use to either 10 or 100 Mbps wired LANs

• Extensions to the IEEE 802.11 standard have given the push needed to make this a rapidly growing technology




IEEE 802.11b/a/gIEEE 802.11b/a/g

• In 1999, IEEE 802.11b provided support for 11 Mbps in the 2.4 GHz band and IEEE 802.11a provided support for rates up to 54 Mbps in the newer 5 GHz ISM band

• In 2003, IEEE 802.11g provided for data rates up to 54 Mbps in the 2.4 GHz ISM band

• Now, vendors sell low cost WLAN access points that support 802.11b/a/g and the radio cards for these standards are readily available and inexpensive




IEEE 802.11xIEEE 802.11x

• There are many other IEEE 802.11x projects in the works to further refine wireless LAN technology:– 802.11e – addresses QoS issues (3G/4G related)– 802.11d – addresses operation in other countries– 802.11i – enhances security (almost complete)– 802.11j – provides support for operation in Japan– 802.11n – provides true data throughput rates in

excess of 100 Mbps




IEEE 802.11x (cont.)IEEE 802.11x (cont.)

• Recently approved IEEE 802.11x standards and new projects (*) include: – 802.11f – addresses interoperability of multi-

vendor access point equipment– 802.11h – addresses operation in Europe in 5

GHz band– 802.11k* – enhances Radio Resource

Measurement capabilities (Cognitive Radio!) – 802.11r* – attempts to improve BSS transitions

and address VoIP issues – 802.11s* – addresses multi-hop or mesh

technology issues– etc




What is IEEE 802.11? What is IEEE 802.11?

• Essentially, the IEEE 802.11 standard provides for the wireless extension of an 802 wired LAN

• Access Points (APs) provide points of connection for portable radio cards or other wireless enabled devices

• There are vendors that sell “bridges” that can extend the WLAN over distances of kms using outdoor high gain antennas

• Set-up is fairly straight forward using windows based software and point-and-click GUIs




IEEE 802.11 status IEEE 802.11 status

• What does the future hold for IEEE 802.11?• Most observers see a large upside to this

technology, however, many predict a limited lifetime with a tapering off of annual Wi-Fi sales sometime during the end of this decade in the pc marketplace

• One might ask why this might happen– WLANs and hot-spots will continue to proliferate

until all those that are economically viable have been installed




IEEE 802.11 status (cont.) IEEE 802.11 status (cont.)

– However, Moore’s Law will continue to have an effect on device technology, with IEEE 802.11 functionality becoming a part of some IC that is eventually a standard feature of a portable device (see below)

– Many predict the demise of the pc as we know it sometime before the end of this decade as it morphs into some other type of device

– Radio Free Intel. This company is making a big push to provide wireless access on each of its microprocessors in the not-too distant future and is also pushing disruptive technology in the form of the IEEE 802.16 standard




IEEE 802.11 status (cont.) IEEE 802.11 status (cont.)

• In related news, the FCC has recently released more spectrum in the 5 GHz range for unlicensed use and is considering the same for the 3.6 GHz band and the TV band.

• The FCC is also considering changes in allowed output power for IEEE 802.11 (i.e. higher in certain areas of the country)

• This push by the FCC could lead to other Wi-Fi applications in the heartland of America




IEEE 802.11 status update IEEE 802.11 status update

• This Monday, July 12th, 2004, the FCC adopted rules changes to Part 15 that affect unlicensed wireless broadband service:– These rule changes are designed to promote use

of unlicensed broadband service in rural areas– Specifically, allowing the use of advanced

antenna technologies such as sectorized or phased array antennas

– Also, allowing alternative replacement antennas, certain external amplifiers, redefining modulation measurement procedures, and alternate frequency hopping specifications




IEEE 802.11 Status (cont.) IEEE 802.11 Status (cont.)

• Also, on July 1st, 2004 New York City released a RFP for an unprecedented wireless public safety network – the world’s largest public safety hotzone!– Network would provide the ability to send and

receive wireless data at 2 Mbps at speeds up to 70 mph

– Project cost is estimated to be between $500 million and $1 billion

– Proposed: meshed WLAN system or a cdma EV-DO network




Wireless PANs/IEEE 802.15Wireless PANs/IEEE 802.15

• Let’s switch our attention to the IEEE 802.15.x technologies

• This standard deals with wireless PANs or wireless networks with a very limited range (i.e. 10 meters maximum)

• Many know this technology as “Bluetooth”• The IEEE 802.15.1 standard calls for

operation in the 2.4 GHz unlicensed ISM band also, using a form of spread spectrum




Bluetooth/IEEE 802.15.1Bluetooth/IEEE 802.15.1

• The application areas envisioned for this standard are:– The elimination of proprietary cables for the

connection of both stationary and portable devices

– Various extensions to the standard have the potential to transform how things are done through the deployment of wireless sensor networks that will support applications in both the commercial/business and consumer/home environments. More about this topic later




IEEE 802.15.1 characteristicsIEEE 802.15.1 characteristics

• Bluetooth wireless networks can transfer data both asynchronously or synchronously in a variety of combinations and rates

• This allows Bluetooth to provide QoS that supports standard voice (i.e. application area – hands free cell phone operation)

• Also, allows vendors the ability to tailor data rates for future applications




IEEE 802.15.1 characteristics IEEE 802.15.1 characteristics (cont.)(cont.)

• Bluetooth networks are low power and ad hoc in nature

• Typical power is 1 mW compared to 100 mW for a wireless LAN

• Network only exists for a limited time• Network may consist of different devices

and may change structure rapidly• Network elements are known as “Master”

and “Slave”• A Bluetooth device may take on either role




Typical IEEE 802.15.1 networks Typical IEEE 802.15.1 networks (piconets) (piconets)

Source: IEEE 802.15.1




Typical IEEE 802.15.1 data rates Typical IEEE 802.15.1 data rates

Source: IEEE 802.15.1

FEC = forward error correction (rate) CRC = cyclic redundancy check




Future IEEE 802.15.1 features Future IEEE 802.15.1 features

Source: IEEE




IEEE 802.15.2IEEE 802.15.2

• Deals with facilitation of the coexistence of IEEE 802.15.x devices and other devices that both use the same unlicensed frequency spectrum

• Two techniques:– Non-collaborative– Collaborative techniques: this type of operation

allows for the exchange of information between an IEEE 802.15 device and an IEEE 802.11 device




IEEE 802.15.3IEEE 802.15.3

• Adopted late in 2003, this standard provides for low cost and complexity, low power consumption, and high data rate (20 Mbps) WPAN operation

• Useful for high-speed multimedia applications with QoS support capabilities

• Follow-on project, IEEE 802.15.3a calls for support for 110 Mbps and higher data transfers using new ultra-wideband transmission technology or some other new technique




IEEE 802.15.3-4 piconets IEEE 802.15.3-4 piconets (basic star operation)(basic star operation)

Source: IEEE




IEEE 802.15.3-4 piconets (cont.)IEEE 802.15.3-4 piconets (cont.)(peer-to-peer topology)(peer-to-peer topology)

Source: IEEE




IEEE 802.15.3-4 piconets (cont.)IEEE 802.15.3-4 piconets (cont.)(cluster tree network)(cluster tree network)

Source: IEEE

This graphic indicates how a cluster tree network may dramatically extend an IEEE 802.15.3 network by forming a mesh of multiple neighboring clusters




IEEE 802.15.4IEEE 802.15.4

• This standard addresses the low rate WPAN application space

• Data transfers less than or equal to 250 kbps, ultra low power consumption, small form factor and complexity

• The ZigBee Alliance is an industrial group with an interest in this technology

• Application area is limitless – weather prediction, crop maintenance, all types of wireless sensor networks – typical present day application: tire pressure sensor




IEEE 802.15.4 characteristicsIEEE 802.15.4 characteristics

Source: IEEE

There is one channel in the 868 MHz band, ten channels in the 900 MHz band, and sixteen channels in the 2.4 GHz band!




IEEE 802.15.x application space IEEE 802.15.x application space summarysummary

Source: IEEE




Wireless MANs/IEEE 802.16Wireless MANs/IEEE 802.16

• A new standard for a old technology, IEEE 802.16 addresses the wireless MAN application space – network access to buildings

• This standard provides the details of the Physical and MAC layers for fixed point-to-multipoint broadband wireless access (today, known as WiMax)

• This technology has existed for many years with proprietary equipment sold primarily to countries without a large installed telecommunications infrastructure




IEEE 802.16 characteristicsIEEE 802.16 characteristics

• Initial standard supports the transfer of voice, data, and video services at frequencies between 10-66 GHz (Line-of-sight (LOS) operation)

• Moore’s Law again! Device improvements at millimeter wavelengths and lower costs have reduced price of system components

• Also, recent changes to unlicensed spectrum have lead to amendments of IEEE 802.16 that address the 2-11 GHz range




IEEE 802.16 characteristics IEEE 802.16 characteristics (cont.)(cont.)

• The FCC has recently released a large amount of previously restricted spectrum in the range of 71-95 GHz for broadband millimeter wave LANs and other broadband Internet services

• Recent moves by the FCC to release 3.5 GHz spectrum for unlicensed use

• IEEE 802.16 was adopted in late 2001 for 10-66 GHz

• Application space: SOHO through small to medium size office complexes




IEEE 802.16a-2003 IEEE 802.16a-2003

• Amendments to IEEE 802.16 provide for operation in the unlicensed bands (covers all frequencies from 2-11 GHz) and deal with Non-LOS and mesh operation

• Another project, IEEE 802.16.e is suppose to provide enhancements that support subscriber stations moving at vehicular speeds

• Basically, a wireless MAN serves as a bridge to an existing network infrastructure




Typical IEEE 802.16 system Typical IEEE 802.16 system

Source: IEEE




IEEE 802.16 physical layersIEEE 802.16 physical layers

• WirelessMAN-SC – for operation in the 10-66 GHz frequency range

• WirelessMAN-SCa – for operation in the 2-11 GHz frequency range

• WirelessMAN-OFDM – for operation in the 2-11 GHz frequency range

• WirelessMAN-OFDMA – for operation in the 2-11 GHz frequency range

• Wireless High-speed Unlicensed MAN or WirelessHUMAN – for operation in license exempt bands in the 2-11 GHz range




IEEE 802.16 operationIEEE 802.16 operation

• Operation is based on the DOCSIS standard

• Various classes of service used for different types of applications

• Intel is also pushing this technology and hopes to market a WiMax chip set in the near future




IEEE 802.20IEEE 802.20

• New IEEE 802 wireless technology project that deals with the delivery of mobile broadband wireless access in the licensed frequency bands in the range of 450 MHz to 3 GHz and supports vehicular speeds up to 250 km/hr (approximately 200 mph)

• Market is all Internet users!• Based on IP mobility




Merging of wireless networksMerging of wireless networks

• Recently, there has been a great deal of interest by the cellular providers in WLAN hot-spots and WLAN technology

• Some have predicted a merging of the networks and seamless operation between the two technologies (3G and Wi-Fi)

• Some have suggested that the cellular subscriber of the future will use the traditional cellular network for wireless WAN operation when appropriate and use a WLAN for network connectivity when in close proximity of a WLAN




The all-IP wireless networkThe all-IP wireless network

• This last statement implies a connection between the two networks and the use of VoIP when connected to the WLAN

• I believe this type of operation is in our future

• 3G/4G networks and IEEE 802 wireless networks will provide seamless connectivity to the IP network worldwide




WLAN connection to a cellular WLAN connection to a cellular networknetwork

Source: Ericsson




SummarySummary

• Wireless connectivity to the IP network is in your future

• Seamless operation as one moves about providing handoffs from wireless network to wireless network with multiple-hop relaying functions commonplace

• The use of wireless sensor networks will change how we do business in many areas

• The best of wireless is yet to come!

www.nctt.org any opinions, findings and conclusions or recommendations expressed in this material...

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