ITEC2706OE
Mobile Technology: Design and Use Fall 2023
Lecture 3
History of Mobile Phone (Continue…)
From Car to the Streets & Into the Shirt Pocket
Today’s Covered Topics:
Basics of Cellular Phone- Cell, Handoff, advantages over
“Zero-G” mobile phone systems
1G
2G and Beyond
GSM Standard
3
rdGeneration
4G
5G
From Car to Streets and into the Shirt pocket
Cellular phone networks are based on the concept of adjacently located coverage areas known as cells.
Each cell contains a transmitting tower.
From Car to Streets and into the Shirt pocket
Handoff: As the user moves from one cell to another cell, the user’s cell phone collaborates with the transmitting towers of the source and destination cells to “handoff” the user from one cell to the next.
The strength of the handoff procedure: the user is totally unaware of the handoff procedure even when the call is in progress.
From Car to Streets and into the Shirt pocket
The black hexagons represent the geographical cells of a cellular network.
Each cell contains a mobile tower at the center of the cell (Towers T1, T2,T3, T4 ).
Each tower transmits into its cell using three different frequencies in three different directions that are 120 degrees apart (shown by the blue double headed arrows).
The actual cell in the cellular network is therefore the red- colored hexagons.
From Car to Streets and into the Shirt pocket
6
Each of the red colored cells is divided into three regions (R1, R2, R3).
Each cell tower services one region within a red cell.
When a mobile phone M1 is switched on, it will scan for signals from all neighboring towers. Since it lies in region R1, it will find the strongest signal coming from tower T1 and begin communicating with it.
MTS & IMTS
The concept of cellular networks, in which mobile towers located inside the small
“cells” would seamlessly hand off calls to towers in neighboring cells as we move around, became reality later in the 20th century.
“Zero-G” mobile phone systems such as AT &T’s Mobile Telephone Service were based on the concept/notion of one large tower serving a large geographical area around it.
Recap- “Zero-G” mobile phone
systems
Drawbacks of early mobile networks (“Zero-G”
mobile phone systems):
VHF range requires Long Antenna.
Could accommodate a small number of subscribers.
Network Congestion and excessive signal interference.
Coverage was a Line-of-sight basis-The whole system worked based on a central base station- if someone went behind a tall building or any other large object-the person immediately lost the signal.
Heavy Weighted.
Earth’s curvature: People could lose the signal even on the absolutely obstruction-less ground when they traveled “over the horizon” with respect to the base station.
Recap- MTS & IMTS
Advantages of Cellular phone network over “Zero-G” mobile phone networks:
Since each cell covers a geographically small area, much less power is needed to transmit and receive signals. This makes cell phone batteries smaller and less heavy. This in turn reduces the overall size and weight of the mobile phone.
Cellular networks operate in the Ultra High Frequency band leading to short antenna designs on the phones instead of the out-sized antenna that were needed by the Very High Frequency-based car phone systems of the 1940s, 50s, and 60s.
The cellular nature of the network avoids the “over-the-horizon” issue faced by the Zero-G networks. A cellular network can scale virtually infinitely over and across mountains, and around tall buildings simply by adding more cells to the network.
On a cellular network two subscribers can talk on the same frequency band as long as they are in different cells. This enormously increases the number of simultaneous conversations that the network can support, and thereby addresses the network congestion problem that Zero-G networks faced.
Advantages of Cellular Networks
The genesis (origin/beginning) of the cellular telephone began as early as the 1940s in Bell labs, USA.
On December 1947, Bell labs researcher Douglas together with his colleagues introduced the concept of adjacently cellular coverage areas to increase the coverage of the mobile telephone service.
However, cellular networking concepts continued to be researched upon all the way through to late 1970s i.e. in parallel with the large-scale roll- out of zero-G networks throughout the whole world.
As the research in the field of cellular telephony continued for 20 years, finally in the 1960s, a set of researchers of Bell lab, gave the full technical rigor (laws) regarding the cellular network, and based on this technical rigor, AT & T finally commercially deployed cellular phone service in America called the Advanced Mobile Phone System
(AMPS). 10
Birth of Cellular telephony concepts
World’s First Handheld, Personal, Portable Cell Phone
11
During the 1960s, while the researchers at Bell labs continued their research on the development of Cellular phone networks, Motorola invested its time to develop the cell phone.
The first real handheld, personal, and portable cell phone was developed by Motorola in 1973 and the cell phone was named as Motorola DynaTAC (1G).
Motorola DynaTAC was 10 inches long, weighed 2 pounds, and needed to be charged for 10 hours for 20 minutes of talk time.
Unfortunately, the size and weight of the DynaTAC quickly earned the name “the brick”.
In 1984, the first commercial version of Motorola DynaTAC was launched and called Motorola DynaTAC 8000X which cost $3,995. The 8000x was somewhat smaller and lighter
than the “brick”.
Motorola DynaTAC 8000X
cell phone
Growth of Cellular Telephony outside United States
USA rolled out its 1G cellular network in the 1980s, but this time Japan and Nordic countries were ahead of the USA.
The world’s first fully automated cellular network was launched not in the USA, but in Japan in 1979 by Nippon Telephone and Telegraph (NTT)- Japan was one of the first countries in the world with 100% 1G cellular coverage.
Two years later in 1981, the fully automated Nordic Mobile
Telephony (NMT) cellular network was launched in Sweden and
Norway, followed by a launch in Denmark and Finland in 1982 and
Iceland in 1986.
Growth of Cellular Telephony outside United States
Interestingly, the first commercial service of Nordic Mobile Telephony (NMT) was started in Saudi Arabia in 1981 even though the network began operation in Sweden.
During the 1980s, NMT spread into several European countries and
Russia. During the same period, AMPS spread its wings across
North America, and its variants- the TACS (Total Access
Communication System), JTACS (Japanese Total Access
Communication System), and ETACS (Extended Total Access
Communication System) spread into the United Kingdom, Ireland,
and Japan.
1G Mobile Phones
1G mobile phones of the 1980s were large, bulky, and power hungry.
1980s began with the famous introduction in 1984 with Motorola DynaTAC (already described)
In 1982, Nokia introduced its first 1G cellular phone: Nokia Mobira Senator 450-operated over 450MHz network and weighed 10 Kg.
Nokia Mobira portable cellular phones of the 1980s
Nokia Cityman series was manufactured from 1987 to 1990.
This series saw the introduction of five Cityman Series phone from Nokia- the Cityman 1320, 900, 150, 190, and 100.
1G Mobile Phones
(Left) Nokia Cityman 100 ETACS Version announced in January 1990, (Right) Cityman 150 announced in 1989. The Nokia 1100 launched in 2003 is also shown at the extreme right for comparison.
1G Mobile Phones
The 1987 Cityman 1320 was a
direct competitor to the Motorola DynaTAC introduced in 1984. The Cityman 1320 was also Nokia’s
first truly handheld phone.
The Cityman series brought a huge reduction in the size of the device.
Cityman 1320 weighed in at ¾ of a
KG and the Cityman 100 weighed in
at just under ½ KG.
1G Mobile Phones
Two other mentionable significant Mobile phones during the 1980s.
Technophone-1984
Swedish engineer started the company Technophone.
1st time a cell phone fitted neatly inside one’s shirt’s pocket.
M1 was by far the first world’s smallest and sleekest mobile phone weighing under 350 grams. And for the first time, a cell phone fitted neatly inside shirt pocket.
Motorolla MicroTAC-1989
Motorola’s clearest shrinked-sized cell phone.
World’s first flip-top phone.
Technophone PC107/3
Motorola MicroTAC 9800x
2G and Beyond
A common characteristic of the 1G cellular systems of the 1980s was that they used analog signals to carry the information between the cell phones and the cell phone towers.
Second Generation (2G) cellular networks were introduced in the early 1990s.
2G networks digitized the communication between the cell phone and the tower.
2G and Beyond
Advantages of the digitized communication between the cell phone and the tower:
Digital communication can be heavily compressed by the phone before transmission. This dramatically reduced the bandwidth requirement for each phone call. Thus, each cell can support many more subscribers than before.
Secondly, the digital signal can be easily encrypted thereby making eavesdropping (listening secretly to a private conversation) much harder to do than with the 1G analog system.
2G and Beyond
Advantages of the digitized communication between the cell phone and the tower (continued):
Digital transmission also consumed less power, thereby further reducing the size and weight of the batteries that were used by the phones.
And there was also no line noise or ‘hum’ during pauses in the conversation.
Finally, a digital transmission made it possible to transmit data over a channel along with voice.
2G and Beyond
The evolution of digital telephony:
Up through the 1990s, the United States, Europe, and Japan- each took a different route for migrating from 1G to 2G.
United States: Created a digital version of the 1G AMPS (Advanced Mobile Phone System). This resulted in two branches:
Motorola designed Narrow Band AMPS.
and Digital AMPS (D-AMPS).
D-APMS was first launched in the US in 1990, and was specifically designed to be backward compatible with the analog AMPS- so people could use a dual mode (analog/digital) cell phone.
2G and Beyond
The evolution of digital telephony:
Japan: Migrated its vast analog cellular network operated by Nippon Telephone and Telegraph (NTT) through the 1980s to a digital variant called Personal Digital Cellular (PDC). This 2D PDC cellular network began operation in 1993
Europe took an altogether different route for 2G adoption.
Some of the member states of European Union (EU) were operating specific variants of the Nordic Mobile Telephony (NMT) cellular network that was launched in Sweden and Norway.
The United Kingdom and Ireland used TACS (Total Access Communication System) and ETACS (Extended Total Access Communication System).
2G and Beyond-GSM
The birth of the GSM standard: The fragmentation of the 1G cellular networks among the European states leads to one of the greatest successful unifications of the cellular networking standards.
In 1987, thirteen European countries agreed and signed to use a
single digital cellular communication standard to be
implemented. This communication standard was known as the
standard in 1990 which is Global System for Mobile
Communications (GSM).
2G and Beyond-GSM
On 10 November 1992, the Nokia 1011 was launched- it quickly became the world’s first mass-produced and commercially successful GSM phone.
The Nokia 1011’s shell had the iconic
“candy bar” shape- a design that was adopted extensively by cell phones in the coming decades.
Nokia 1011
2G and Beyond-GSM
GSM quickly established itself as the 2G cellular network of choice across Europe.
GSM continued to be adopted worldwide at a stunning surprising rate.
Today it is estimated that more than 80% of the mobile phone-
carrying population of the planet communicates over the 2
ndgeneration (2G) GSM networks or an evolved version of it.
GSM Standard-CSD
By 1991, GSM-based cell phones started providing wireless data transmission capability using a new kind of data transfer protocol called Circuit Switched Data (CSD).
In CSD, Time Division Multiple Access (TDMA) radio timeslot is dedicated o the transmission of data signals.
From the network’s perspective-when a user transmits data, and the cell phone places a “Data call” using CSD over a dedicated wireless data channel between the phone and the base station.
With CSD in 1991, data could be transferred over the 2G cell phone network at speed of 9.6 kbps. This speed might seem a very tiny change compared to today while streaming a movie over 3G or 4G- however, even at 9.6 kbps, the first circuit switched 2G networks of the early 1990s had taken a giant step using the same wireless channel for both voice and data traffic.
GSM Standard-GPRS (2.5G) and EDGE (2.75G)
During the 1990s, the data rate of CSD quickly enhanced via the development of several efficient data transfer protocols such as High Speed Circuit Switched Data (HSCSD) protocol boosted data transfer rates to 57 kbps.
By the year 2000, the introduction of the General Packet Radio Service (GPRS) protocol for wireless data transmission further boosted mobile data rates to 114 kbps (theoretically).
EDGE (Enhanced Data Rates for GSM Evolution): By 2003, cell phone carriers began offering mobile services based on EDGE protocol which increased data rates to as high as two or four times what could be achieved via GPRS i.e. in the range 236-474kbps.
Over the turn of the 21st century (20th century-in 1900s), GPRS was just good enough for low bandwidth wireless data exchange and access website contents over low bandwidth wireless connections. This was the era of the Wireless Access Protocol (WAP) based websites.
GSM Standard-GPRS(2.5G) and EDGE(2.75G)
Introduction of EDGE protocol in 2003 as a successor to GPRS, pushed the data rates to 250 kbps.
With Edge, multimedia data file transfers, sharing of photos from the phone, downloading audio files into the cell phones for playback, and sharing small videos became a reality.
But people had to wait long for video conferencing straight
from their cell phones with the introduction of third-
generation data services.
3G-UMTS
GPRS and EDGE protocols are called 2.5G and 2.75G respectively as they go beyond the Circuit Switched Data (CSD) based data transfer specifications within the original GSM 2G standard.
The evolution of faster and faster data speeds from CSD to High speed CSD (HSCSD) to General Packet Radio Service (GPRS) and EDGE- evolved to UMTS (Universal Mobile Telecommunication System).
UMTS is a 3G cellular system based on the GSM standard and is known as 3GPP (3rd Generation Partnership Project).
3G UTMS could support download data rates of 384 kbps which is an increment over EDGE’s 250 kbps.
3G-UMTS
3G GSM is actually called a Wideband CDMA (WCDMA) based technology.
In 2001, Japan launched the first 3G service based on WCDMA technology.
Code-division multiple access (CDMA): is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies or bandwidth). To permit this without interference between the users, CDMA employs a special coding scheme (where each transmitter is assigned a code).
3G-UMTS-WCDMA
In 3G GSM, certain speed boosting enhancements came to UMTS (Universal Mobile Telecommunication System) called as High Speed Packet Access (HSPA).
HSPA consists of High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA).
These enhancements made the data transfer rate to 14Mbps (theoretically)-Practically 7-10Mbps.
HSPA and HSPA+ are sometimes called 3.5 G, 3.75G or 3.9G technologies as they pushed the data transfer rate of the 3G.
3G-At USA-Embraced GSM
While the GSM based revolution was underway in Europe and Japan, in USA cdmaOne was born (Previously had DAMPS).
The GPRS (2.5G), EDGE (2.75G) and UMTS (3G) and HSPA (3.5G)- all these protocols progressively offered faster data transmission speeds over the base GSM protocol.
In USA, cdmaOne evolved via the introduction of the CDMA2000 family of 3G standards.
South Korea also adopted cdmaOne.
Interestingly, even in the North American market, GSM appears to be strong.
AT &T’s vast network embraced GSM instead of remaining wedded to CDMA2000.
4G
4G cellular systems are a significantly evolved version of 3G to the point where there is basically no backward compatibility with 3G. The reason is that, 4G standard does not support any Circuit-switched based telephony and thereby completely departs from the technology that has been the mainstay of mobile telephone networks since their inception in the 1940s.
4G cellular systems are based on all IP (Internet Protocol) networks.
In 2008, International Telecommunications Union- Radio Communications Sector (ITU-R) set the requirements for 4G network.
ITU-T set the minimum data transmission speed bar for 4G systems at 100 Mbps when the Mobile device is in high speed motion and at a speed of 1 Gbps when the user is stationary and moving slowly(walking down the street).
4G
Three mobile systems called LTE, WiMAX and HSPA+ closely meet the requirements of 4G.
LTE (Long Term Evolution): was proposed by NTT-Japan in 2004.
Voic and data on LTE based wireless network are packetized into-IP packets.
For data, LTE supports a maximum download speed of 300 Mbps and an upload speed of 75Mbps.
WiMAX (Worldwide Interoperability for Wireless Access): is a wireless communication protocol standard by the Institute of Electrical and Electronics Engineers (IEEE).
The most well-known WiMAX protocol is IEEE 802.11 WiFi standard that our computer and WiFi access point use.
WiFi offers speeds of 30-70Mbps in both directions.
4G-HSPA+ and LTE- Advanced
HSPA+ evolved from HSPA (High Speed Packet Access) and provides download speeds of up to 168 Mbps and upload speeds of up to 22 Mbps.
LTE-advanced evolved from LTE.
Since LTE, WiMAX, and HSPA don’t meet the speed requirements of 4G, they can be best called as 3.75G to 3.9G.
The first LTE based 4G rollout was made in Stockholm and in Oslo in 2009.
Today (2015), LTE and WiMAX cover a substantial fraction of the cell phone-carrying population of the world
