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GLOSSARY 189Table 3Service Differentiation by Wireless Communication Generations2G 2.5G 3GCircuit switched Packet services Multimedia
Voice Interactive High interactivity
Simple message/SMS Web browsing Real time road maps
Event notification E-mail and attachments Medical imaging
Fax File transfers MMS
Transactions/e-commerce Audio streaming
Instant messaging Video streaming
Video telephony
Weighted fair QoS End-to-end QoS
GSM GPRS 3GPP (EDGE, UMTS)but also uses more bandwidth than digital voice ser-
vices. W-CDMA is not the only 3G technology; competing
technologies include CDMAOne, variants of CDMA2000,
which differs technically, but should provide similar ser-
vices.CONCLUDING REMARKS
RF and wireless communication systems are being used
in diverse areas such as home, military, travel, education,
stock trading, package delivery, disaster recovery, and
medical emergencies. For example, with wireless technol-
ogy field employees can connect a portable computer via
a wireless network to the area office. Sales professionals
can stay in touch with customers about products and ser-
vices, placed orders, status updates to home offices, and
inventory. Airline staff can gather information about tick-
eting, flight scheduling, and luggage using wireless de-
vices. Public welfare agencies such as police, fire safety,
and ambulance services can use wireless devices to relay
information. Package delivery companies such as Federal
Express, UPS, and DHL have adopted the wireless and
mobile computing technology for parcel tracking, as well
as emergency drop or pickups of shipments.
Although wireless systems are commonplace in our so-
ciety, the future of the industry is filled with promises
and challenges. Future wireless technologies under con-
sideration include 4G mobile technology, multimedia
messaging, and complete convergence via broadband,
just to mention a few 4G wireless technology based on
ultra-wideband communications will enable the use of
low-power, high-bandwidth (100–500 Mbps) networks,
supporting devices with sense and radar capabilities. Mul-
timedia messaging will allow pictures and sound to be
transmitted along with a text message over the mobile
phone. Mobile handsets will support full-color display
screens, some with embedded Java capabilities, others
with digital cameras built in. It is expected that Bluetooth
technology will move from theory and hype to practical-
ity, and issues regarding the security of mobile commerce
and information security in general will dissipate.
In this chapter, the topics of RF and wireless commu-
nication have been discussed. The concept and general
definitions are presented. Within these topics, we have
discussed the concept of radio waves as propagating elec-
tromagnetic waves, including their characteristics andbehavior. It is noted that for wireless and mobile radio
systems, it is important to understand distinguishing fea-
tures of the channel, the properties of the radio wave, and
several techniques to enhance the reliability of the chan-
nel and increase the performance of the system. Also, a
summary of the different forms of wireless communica-
tion systems was presented, emphasizing cellular mobile
radio, which is currently the most prevalent wireless com-
munication system. Finally, the up-and-coming wireless
technologies were enumerated. These are the 3G tech-
nologies, which will provide more capabilities to their
users.GLOSSARY
1G, 2G, 3G, 4G 1st, 2nd, 3rd and 4th generation wireless
systems.
Amplifier An electronic device used to boost the
strength of a signal along a communications channel.
Antenna A device used for receiving or transmitting sig-
nals.
Bandwidth The capacity of a transmission channel.
Base station Central radio transmitter/receiver that
maintains communications with a mobile radio user.
Bluetooth Short-range wireless protocol allowing mo-
bile devices to share information and applications.
Broadband A classification of the information capacity
or bandwidth of a communication channel.
CDMA Code division multiple access.
Cellular Wireless communication technique used in
mobile phones.
Channel A radio-frequency assignment made according
to the frequency band being used.
Downlink Data transmission from a network to a sub-
scriber.
DSSS Direct sequence spread spectrum.
Duplexer Device for isolating transmitter and receiver
signals while permitting a shared channel.
EIRP Effective isotropic radiated power: product of
power supplied to an antenna and its gain.
FHSS Frequency hopping spread spectrum.
Frequency Rate of signal oscillation in hertz (one hertz
is one cycle per second): the number of times a wave-
form repeats itself in a second.
GPS Global positioning system—a worldwide radio-
navigation system.