FDMA, TDMA, CDMA: Multiple Access Techniques

This assignment delves into the realm of multiple access techniques used in wireless communication, focusing on Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Code Division Multiple Access (CDMA). It examines the defining characteristics of each technique, including how they allocate resources and handle signal transmission. The assignment also provides a comparative analysis of FDMA, TDMA, and CDMA, highlighting their strengths and weaknesses in various communication scenarios.

Running head: WIRELESS NETWORKING CONCEPTS
Assignment
[Student Name Here]
[Institution’s Name Here]
[Professor’s Name Here]
[Date Here]

WIRELESS NETWORKING CONCEPTS 2
Task 1
Antennas are devices that are used in wireless communication to propagate RF signals over
the radio spectrum. These devices are classified based on their operational methods which
yield the following categories:
a. Directional antennas – as the name suggests, they transfer radio waves in specific
directions i.e. only one direction e.g. Yagi antenna.
b. Semi directional – transfer signals in multiple directions having restrictions in others.
c. Omnidirectional antennas – transfer radio signals in all directions e.g. cellular antenna
(Reckeweg, 2011).
Horn antenna – a directional antenna that is associated with high gains and directivity
(propagation in one direction). It used in conjunction with ultra-high frequencies
(microwaves) 300MHz – 3 GHz (Radio-electronics, 2017).
Strengths
 High gains and directivity.
 Simple to design
Weaknesses
 Gain is limited to the device structure
Yagi antenna – one of the most popular antenna (directional) that is commonly used in the
propagation of television signals, a common household item. Its properties facilitate its long
distance applications (Rouse, 2017).
Strengths
 Relatively high gains and directivity.

WIRELESS NETWORKING CONCEPTS 3
 A simple structure made of metallic rods.
Weaknesses
 Gains are always limited
 Its size determines the gain.
Cellular antenna – used in mobile devices, a cellular antenna is a good example of Omni-
directional antennas as it propagates RF signals in all directions. It’s usually small in size, an
attribute that facilities its applications (Carr, 2012).
Strengths
 Optimal gains
 Convenient size
Weaknesses
 Limited gains
Future of antenna applications
High gains and directivity are needed when propagating RF signals in long distances, which
necessitates the antennas that exhibit these properties. In this case, directional antennas are
defiantly the choice as they currently exhibit both of these attributes. Moreover, with the
advances in technology, these attributes can be furnished to enhance their operations.
Omnidirectional antennas, on the other hand, are only desirable in short distance applications
and in systems that require small devices (Carr, 2012)..
Task 2
Multiple access techniques (multiplexing techniques) are protocols used to transfer multiple
signals in single channels. In essence, a single communication medium such as the radio

WIRELESS NETWORKING CONCEPTS 4
spectrum (wireless communication) will carry a single RF signal between two corresponding
parties, an undesirable outcome as the medium is wasted. Instead, the multiplexing
techniques use the same channel to carry many signals between many communicating parties.
This outcome optimises the resources available more so, bandwidth which in wireless
communication is limited. However, the techniques must provide optimal operational
conditions where communication is both done efficiently and without recurring instances of
interference (corps, 2000).
Types of multiplexing
Classification is done based on the operational methods, this is determined by the principle
used to facilitate the sharing of the communication medium.
Code division multiple access (CDMA) – in this technique, communication will start with a
unique set of codes. These codes are assigned to the propagated signals and are used as
identification factors. Moreover, the users involved will possess the same codes which will
facilitate their communication based on matching identifiers. Now, during communication
(propagation of signals), all signals are ferried under the same medium without the allocation
of space. Therefore, the entire bandwidth is available for signals during transmission, unlike
other techniques (TECH, 2011).
CDMA properties:
 Pseudo-codes ( a unique set of codes) are used as the multiplexing factor.
 Signals use the entire bandwidth without any form of allocation of space.
 Users having matching codes can communicate with each other.
Frequency division multiple access (FDMA) – frequency bands are used to allocate space
within the communication medium. In wireless communication, the radio spectrum is the
medium and is split into different sub-band frequencies, with each band carrying a unique

WIRELESS NETWORKING CONCEPTS 5
signal. During communication, the users will possess their band which are minor channels
(subsections) of the entire communication channel. Therefore, FDMA will allocate space
based on the needs of the users (Zahra, 2015).
FDMA properties
 Frequency bands are the multiplexing factor.
 Allocation of space is done.
 Users’ possess minor communication channels.
Comparison of the two techniques
CDMA FDMA
Defined by pseudo codes which uniquely
identify signals across the communication
medium.
Frequency bands define the technique,
assigning space across the communication
channel.
All signals will use the entire bandwidth as
the technique does not assign space to the
parties involved.
The bandwidth is divided according to the
signals involved. This means each
signal/user is allocated space with the
medium.
The channel never experiences idle time as
every instance is associated with a transfer
of a signal.
Due to the allocation of space, some bands
will remain idle when their respective users
are not communicating.
Commonly used with both video and data
signals as it provides maximum bit transfer.
Used to transfer audio signals, a common
application with radio transmissions.
No filters. Filters are used enhance the efficiency of
communication as they eliminate
interferences (Zahra, 2015).

WIRELESS NETWORKING CONCEPTS 6
References
Carr, J. (2012). Directional or Omnidirectional antenna? . Joe Carr's Radio Tech-notes,
Retrieved 14 August, 2017, from: http://www.dxing.com/tnotes/tnote01.pdf.
Carr, J. (2012). Directional or Omnidirectional antenna? Joe Carr's Radio Tech-notes,
Retrieved 14 August, 2017, from: http://www.dxing.com/tnotes/tnote01.pdf.

WIRELESS NETWORKING CONCEPTS 7
corps, W. (2000). FDMA vs. TDMA vs. CDMA. Connecting Wireless, Retrieved 14 August,
2017, from: http://wirelessapplications.com/pdf/lf/FD_TD_CDMA.pdf.
Radio-electronics. (2017). Microwave Horn Antenna. Antennas and propagation, Retrieved
19 August, 2017, from:
www.radio-electronics.com/info/antennas/horn_antenna/horn_antenna.php.
Reckeweg, M. (2011). Antenna basic. Rhode & Schwarz, Retrieved 14 August, 2017, from:
https://home.zhaw.ch/kunr/NTM1/literatur/Rhode_Schwarz_Antenna_Basics.pdf.
Rouse, M. (2017). Horn antenna. Research gate, Retrieved 17 August, 2017, from:
http://searchmobilecomputing.techtarget.com/definition/horn-antenna.
TECH, M. C. (2011). Multiple access techniques for wireless communications. wireless
mobile communication , Retrieved 19 August, 2017, from:
https://www.slideshare.net/HILDA519/multiple-access-techniques-for-wireless-
communications.
Zahra. (2015). FDMA-TDMA-CDMA. Multiple access techniques in wireless
communication, Retrieved 16 August, 2017, from:
https://www.slideshare.net/SammarKhan2/fdmatdmacdma.