History of Wireless Communication
Wireless Communication
Wireless communication — otherwise known as “over the air” —is the electromagnetic transfer of
information between two or more points that are not connected by an electrical conductor. The most
common wireless technologies use radio waves. With radio waves, intended distances can be short,
such as a few meters for Bluetooth or as far as millions of kilometers for deep-space radio
communications. It encompasses various types of fixed, mobile, and portable applications, including
two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other
examples of applications of radio wireless technology include GPS units, garage door openers, wireless
computer mouse, keyboards and headsets, headphones, radio receivers, satellite television, broadcast
television and cordless telephones. Somewhat less common methods of achieving wireless
communications include the use of other electromagnetic wireless technologies, such as light,
magnetic, or electric fields or the use of sound. There are several generations in wireless
communication ranging from 1G to 5G.
Evolution of Wireless Technologies
Second Generation (2G) - 1990s
2G, first introduced in 1992, is the second-generation of cellular telephone technology and the first to
use digital encryption of conversations. 2G networks were the first to offer data services and SMS text
messaging, but their data transfer rates are lower than those of their successors. Three primary
benefits of 2G networks over their predecessors were that; phone conversations were digitally
encrypted, allowing the transfer of data in such a way that only the intended receiver can receive and
read it, significantly more efficient use of the radio frequency spectrum enabling more users per
frequency band and data services for mobile, starting with SMS text messages, picture messages, and
MMS (multimedia messages).
While radio signals on 1G networks are analog, radio signals on 2G networks are digital. Both systems
use digital signaling to connect the radio towers (which listen to the devices) to the rest of the mobile
system. With General Packet Radio Service (GPRS), 2G offers a theoretical maximum transfer speed of
40 Kbit/s. With EDGE (Enhanced Data Rates for GSM Evolution), there is a theoretical maximum
transfer speed of 384 Kbit/s. The most common 2G technology was the Time Division Multiple Access
(TDMA)-based GSM, originally from Europe but used in most of the world outside North America.
Technologies
Data Rate
2G
GSM
10 kbps
2G
CDMA
10 kbps
2.5G
GPRS
~50 kbps
2.5G
EDGE
~200 kbps
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Third Generation (3G) - 2000s
3G (short for third generation) is the third generation of wireless mobile telecommunications
technology. It is the upgrade for 2.5G and 2.5G GPRS networks, for faster data transfer speed. This is
based on a set of standards used for mobile devices and mobile telecommunications use services and
networks that comply with the International Mobile Telecommunications-2000 (IMT-2000)
specifications by the International Telecommunication Union.
3G telecommunication networks support services that provide an information transfer rate of at least
144 Kbit/s. Later 3G releases, often denoted 3.5G and 3.75G, also provide mobile broadband access
of several Mbit/s to smartphones and mobile modems in laptop computers. This ensures it can be
applied to wireless voice telephony, mobile Internet access, fixed wireless Internet access, video calls
and mobile TV technologies.
Technologies
Data Rate
3G
WCDMA/UMTS
~384 kbps
3G
CDMA 2000
~384 kbps
3.5G
HSDPA/HSUPA
5-30 Mbps
3.5G
1 EVDO Rev A, B, C
5-30 Mbps
Fourth Generation (4G) - 2010s
4G is the fourth generation of mobile phone communications standards. It is a successor of the 3G
and provides ultra-broadband internet access for mobile devices. A 4G system must provide
capabilities defined by ITU in IMT Advanced. The high data transfer rates make 4G networks suitable
for use in USB wireless modems for laptops and even home internet access. Potential and current
applications include amended mobile web access, IP telephony, gaming services, high-definition
mobile TV, video conferencing, and 3D television.
The first-release Long Term Evolution (LTE) standard was commercially deployed in Oslo, Norway, and
Stockholm, Sweden in 2009, and has since been deployed throughout most parts of the world. It has,
however, been debated whether first-release versions should be considered 4G LTE.
Technologies
Data Rate
4G
LTE
100-200 Mbps
4G
WiMAX
100 Mbps
Fifth Generation (5G) - 2020s
5G is the fifth generation of wireless communications technologies supporting cellular data networks.
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5G communication requires the use of communications devices (mostly mobile phones) designed to
support the technology. The frequency spectrum of 5G is divided into millimeter waves, mid-band,
and low-band. 5G mid-band is the most widely deployed, in over 30 networks. Many areas can be
covered simply by upgrading existing towers, which lowers the cost. Mid-band networks have better
reach, bringing the cost close to the cost of 4G. 5G low-band offers similar capacity to advanced 4G.
The ITU-R has defined three main uses for 5G. They are Enhanced Mobile Broadband (eMBB), Ultra
Reliable Low Latency Communications (URLLC), and Massive Machine Type Communications (mMTC).
Applications in 3G/4G Wireless Systems
In each generation the data rate and the reliability increases in the technologies.
Generation
Data Rate
Applications
2G & 2.5G
10-100 kbps
voice + basic Data Access
3G & 3.5G
300 kbps - 30 Mbps
voice, High Speed Data Access, video calling
4G
>100 Mbps
online gaming, video conferencing, HDTV transmission
5G
400 Mbps - 2 Gbps
eMBB, URLLC, mMTC
Different Technologies used in Wireless Communication
Global System for Mobile Communications (GSM)
The Global System for Mobile Communications (GSM) is a standard developed by the European
Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation (2G)
digital cellular networks used by mobile devices such as mobile phones and tablets. 2G networks
developed as a replacement for first generation (1G) analog cellular networks. The GSM standard
originally described a digital, circuit-switched network optimized for full duplex voice telephony.
General Packet Radio Service (GPRS)
General Packet Radio Service (GPRS) is a packet oriented mobile data standard on the 2G and 3G
cellular communication network's global system for mobile communications (GSM). In 2G systems,
GPRS provides data rates of 56–114 Kbit/sec. 2G cellular technology combined with GPRS is sometimes
described as 2.5G, that is, a technology between the second (2G) and third (3G) generations of mobile
telephony. It provides moderate-speed data transfer, by using unused time division multiple access
(TDMA) channels in, for example, the GSM system.
Enhanced Data rates for GSM Evolution (EDGE)
Enhanced Data rates for GSM Evolution (EDGE) is a digital mobile phone technology that allows
improved data transmission rates as a backward-compatible extension of GSM. Through the
introduction of sophisticated methods of coding and transmitting data, EDGE delivers higher bit-rates
per radio channel, resulting in a threefold increase in capacity and performance compared with an
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ordinary GSM/GPRS connection. EDGE can be used for any packet switched application, such as an
Internet connection.
High Speed Downlink Packet Access (HSDPA)
High Speed Downlink Packet Access (HSDPA) is an enhanced 3G (third-generation) mobile
communications protocol in the High-Speed Packet Access (HSPA) family. HSDPA is also known as
3.5G, 3G+, or Turbo 3G. It allows networks based on the Universal Mobile Telecommunications System
(UMTS) to have higher data speeds and capacity. The improvement in speed and latency reduces the
cost per bit and enhances support for high-performance packet data applications.
High-Speed Uplink Packet Access (HSUPA)
High-Speed Uplink Packet Access (HSUPA) is a 3G mobile telephony protocol in the HSPA family. This
technology was the second major step in the UMTS evolution process. It was specified and
standardized in 3GPP Release 6 to improve the uplink data rate to 5.76 Mbit/s, extending the capacity,
and reducing latency. Together with additional improvements, this creates opportunities for a number
of new applications including VoIP, uploading pictures, and sending large e-mail messages.
Code Division for Multiple Access (CDMA)
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. To permit this without undue interference between the users, CDMA
employs spread spectrum technology and a special coding scheme (where each transmitter is assigned
a code). CDMA is used as the access method in many mobile phone standards. IS-95, also called
"cdmaOne", and its 3G evolution CDMA2000, are often simply referred to as "CDMA", but UMTS, the
3G standard used by GSM carriers, also uses "wideband CDMA", or W-CDMA, as well as TD-CDMA and
TD-SCDMA, as its radio technologies.
Evolution-Data Optimized (EVDO)
Evolution-Data Optimized (EV-DO, EVDO, etc.) is a telecommunications standard for the wireless
transmission of data through radio signals, typically for broadband Internet access. EV-DO is an
evolution of the CDMA2000 (IS-2000) standard which supports high data rates and can be deployed
alongside a wireless carrier's voice services. It uses advanced multiplexing techniques including code
division multiple access (CDMA) as well as time division multiplexing (TDM) to maximize throughput.
It is a part of the CDMA2000 family of standards and has been adopted by many mobile phone service
providers around the world particularly those previously employing CDMA networks. It is also used on
the Globalstar satellite phone network.
Long-Term Evolution (LTE)
In telecommunications, Long-Term Evolution (LTE) is a standard for wireless broadband
communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA
technologies. It increases the capacity and speed using a different radio interface together with core
network improvements. LTE is the upgrade path for carriers with both GSM/UMTS networks and
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CDMA2000 networks. The different LTE frequencies and bands used in different countries mean that
only multi-band phones are able to use LTE in all countries where it is supported.
Worldwide Interoperability for Microwave Access (WiMAX)
WiMAX (Worldwide Interoperability for Microwave Access) is a family of wireless broadband
communication standards based on the IEEE 802.16 set of standards, which provide multiple physical
layer (PHY) and Media Access Control (MAC) options. WiMAX was initially designed to provide 30 to
40 megabit-per-second data rates, with the 2011 update providing up to 1 Gbit/s for fixed stations.
The latest version of WiMAX, WiMAX release 2.1, popularly branded as/known as WiMAX 2+, is a
smooth, backwards-compatible transition from previous WiMAX generations.
Multiple Input Multiple Output (MIMO)
In radio, multiple-input and multiple-output, or MIMO, is a method for multiplying the capacity of a
radio link using multiple transmission and receiving antennas to exploit multipath propagation. MIMO
has become an essential element of wireless communication standards including IEEE 802.11n (WiFi), IEEE 802.11ac (Wi-Fi), HSPA+ (3G), WiMAX (4G), and Long Term Evolution (4G LTE). More recently,
MIMO has been applied to power-line communication for 3-wire installations as part of ITU G.hn
standard and HomePlug AV2 specification.
MIMO is also planned to be used in Mobile radio telephone standards such as recent 3GPP and 3GPP2.
In 3GPP, High-Speed Packet Access plus (HSPA+) and Long Term Evolution (LTE) standards take MIMO
into account. Moreover, to fully support cellular environments, MIMO research consortia including
IST-MASCOT propose to develop advanced MIMO techniques, e.g., multi-user MIMO (MU-MIMO).
MIMO technology can be used in non-wireless communications systems. One example is the home
networking standard ITU-T G.9963, which defines a powerline communications system that uses
MIMO techniques to transmit multiple signals over multiple AC wires (phase, neutral and ground).
Orthogonal Frequency Division Multiplexing (OFDM)
In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital
transmission, and a method of encoding digital data on multiple carrier frequencies. OFDM has
developed into a popular scheme for wideband digital communication, used in applications such as
digital television and audio broadcasting, DSL internet access, wireless networks, power line networks,
and 4G mobile communications. OFDM is a frequency-division multiplexing (FDM) scheme used as a
digital multi-carrier modulation method. The main advantage of OFDM over single-carrier schemes is
its ability to cope with severe channel conditions without complex equalization filters. Channel
equalization is simplified because OFDM may be viewed as using many slowly modulated narrowband
signals rather than one rapidly modulated wideband signal.
In coded orthogonal frequency-division multiplexing (COFDM), forward error correction
(convolutional coding) and time/frequency interleaving are applied to the signal being transmitted.
This is done to overcome errors in mobile communication channels affected by multipath propagation
and Doppler effects. In practice, OFDM has become used in combination with such coding and
interleaving, so that the terms COFDM and OFDM co-apply to common applications.
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