Wireless Networks Assignment: Antenna Types and CDMA/FDMA Analysis

This document presents a comprehensive solution to a wireless networks assignment, addressing key concepts in the field. The assignment begins with a detailed exploration of various antenna types, including travelling wave antennas, microwave antennas, reflector antennas, log periodic antennas, and wire antennas, highlighting their characteristics, advantages, and disadvantages. It then delves into the comparison of Code Division Multiple Access (CDMA) and Frequency Division Multiple Access (FDMA) technologies, explaining their operational principles, applications, and comparative advantages. The solution provides a clear understanding of the core concepts of wireless communication and access technologies, making it a valuable resource for students studying electrical engineering and related fields. The assignment concludes with a list of relevant references to support the analysis and findings presented.

Running head: WIRELESS NETWORKS
Wireless networks
Name of the student
Name of the University
Author Note

1WIRELESS NETWORKS
Answer to question 1:
The antennas present in the modern world are used to provide a connection via the use of
free space between receiver equipment and its corresponding transmitter equipment. There are
many categories of the antennas present in the modern times. They are:
 Travelling wave antennas (Helical Antenna, Yagi-Uda Antenna)
 Microwave Antennas (Planar Inverted-F Antenna, Rectangular Micro strip Antenna,)
 Reflector Antennas (Parabolic Reflector, Corner Reflector,)
 Log Periodic antennas (Bow Tie Antenna, Log-Periodic Dipole Array)
 Wire antennas (Short Dipole Antenna, Dipole Antenna, Monopole Antenna and Loop
Antenna)
The travelling wave antennas are the first type of antenna. It includes the helical and the
Yagi-Uda antenna. These types of antennas use a guided media for the transmission of the
radiation properties. These types of antennas work via the propagation of the radiation
characteristics along the axis of the antenna involved (Stutzman, & Thiele, 2012). The
advantages of this type of antenna are the higher directivity and gain. The less power
consumption and waste is also another advantage of this type of antenna. However, the less
resistance to noise and less resistance to the atmospheric fluctuations are the disadvantages of
these types of antenna.
Microwave antennas are those types of antenna whose working depends on the use of
microwave radiation energy for the transmission and reception of signals (Hamidi et al., 2012).
High bandwidth and low interference are included in the advantages of these types of antennas
while the line of sight requirements for working is the main disadvantages.

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The reflector antenna works by the use of curved surface reflectors to help focus the
radiations on the antenna. The main advantages of this type of antenna are the presence of high
bandwidth and gain while the main disadvantages are the sole requirements of reflectors.
The use of directional structures and the multi-elements are the specifications of the log-
based antennas. Due to change in frequency, the characteristics of operation cause a shift in the
active region leading to transmission and reception (Hancock et al., 2013). The presence of
stable resistance over a range of frequencies and high bandwidth is the main advantages. The low
gain contributes to disadvantages.
Wire or linear antennas are based on the presence of two metal rods, which is present to
act as the main radiation element in the concerned antenna. The main advantages are the design
simplicity and undistorted output. However, the large size proposes disadvantages.
In addition, the main antennas that are used for connection for long range as well as
medium range communications are the directional antennas. The wide ranges of operation are the
most required specification, which makes this antenna, type a preferred choice.
Answer to question 2:
Code Division Multiple Access (CDMA) is a conceptual process, which involves the
concept of multiplexing that is used to enable various signals to utilize an only channel for
transmission or reception. This type of technology is used for the Ultra High Frequency bands
(UHF). As the name suggests, the data and the voice signals that are intended for transmission
and reception is separated by the presence of specific codes. These codes are then transmitted
using a much wider range of frequency. The user who is sending the signals is assigned a
specific code, which defines the allotment of a specific portion of the channel bandwidth

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(Ghafouri-Shiraz & Karbassian, 2012). The further use of the main techniques involved in
CDMA are the Direct sequence Code Division Multiple Access (DS-CDMA) and the frequency
hopped Code Division Multiple Access. The codes that are assigned to the users for transmission
or reception are orthogonal to the other codes. This process forms the core process of the Code
Division Multiple Access technology and helps the transmitters or receiver to recognize the
signal that is intended for them. The process of operation in Code Division Multiple Access
(CDMA) involves the presence of interference and noise. This technology used in Code Division
Multiple Access (CDMA) became the main standard for third generation mobile internet access
(3G).
Frequency Division Multiple access (FDMA) is a technology in which the available
channel bandwidth is used to be divided into smaller channels that have the same frequencies.
The Frequency Division Multiple access (FDMA) is also used to provide multiple access
protocols over the channelization protocols. These smaller channels thus formed helps in the
reception or transmission as intended (Ochiai, 2012). Due to the overlapping of these small
channels, the concept of guard bands is used. These bands are smaller frequency bands that are
present between two smaller consecutive channels. The guard bands helps in identification of the
channel involved and responsible for minimizing the overlapping interference among the
channels involved. The channels that are intended for transmission of signals for one user is sent
at the transmitter side and that signal is received at the receiver side. The guard bands present
helps in identification of the channels involved. The first generation analog telephones use this
type of technology. Frequency Division Multiple access (FDMA) is also used for communication
in satellites. The basic operation of Frequency Division Multiple access (FDMA) involves the
transmission of a lower bandwidth signal with a higher bandwidth signal. The higher bandwidth

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signal is termed as the carrier and the lower bandwidth signal is termed as the information signal.
Together, they form the main ideas for modulation.
Comparison between FDMA process CDMA process (Patil, Karhe & Aher, 2012)
FDMA
Channel is seemed idle when its use is not going.
The presence of narrow bandwidth is a hindrance for the FDMA
Symbol spreading requires less equalization
Analog links use the presence of FDMA
Tight filtering reduces the presence of interference
Frequency division duplex (FDD) combined with FDMA creates duplexing of the signal.
CDMA
The use of same frequency for the simultaneous transmission of the signals
Widespread spreading accompanies the narrowband signals
The codes to be identified in the receiver are analyzed and the rest are termed as noise
The code of the transmitter is needed in the receiver side

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References:
Ghafouri-Shiraz, H., & Karbassian, M. M. (2012). Optical CDMA networks: principles, analysis
and applications (Vol. 38). John Wiley & Sons.
Hamidi, Z. S., Abidin, Z., Ibrahim, Z., Shariff, N., & Monstein, C. (2012). Modification and
Performance of Log Periodic Dipole Antenna. International Journal of Engineering Research
and Development, 3(3), 36-39.
Hancock, C. P., Dharmasiri, N., White, M., & Goodman, A. M. (2013). The design and
development of an integrated multi-functional microwave antenna structure for biological
applications. IEEE Transactions on Microwave theory and Techniques, 61(5), 2230-2241.
Ochiai, H. (2012). On instantaneous power distributions of single-carrier FDMA signals. IEEE
Wireless Communications Letters, 1(2), 73-76.
Patil, C. S., Karhe, R. R., & Aher, M. A. (2012). Review on Generations in Mobile Cellular
Technology. International Journal of Emerging Technology and Advanced Engineering, 2(10).
Stutzman, W. L., & Thiele, G. A. (2012). Antenna theory and design. John Wiley & Sons.