Wireless Applications-Free-Samples for Students-Myassignmenthelp

Questions: 1.Discuss about the advantages and disadvantages of Wireless technology. 2.How wireless communications are made possible by a radio wave. Answers: 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: Directional antennas as the name suggests, they transfer radio waves in specific directions i.e. only one direction e.g. Yagi antenna. Semi directional transfer signals in multiple directions having restrictions in others. 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. 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. Its 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).. 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 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 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). References Carr, J. (2012). Directional or Omnidirectional antenna? . Joe Carr's Radio Tech-notes, Retrieved 14 August, 2017, from: https://www.dxing.com/tnotes/tnote01.pdf. Carr, J. (2012). Directional or Omnidirectional antenna? Joe Carr's Radio Tech-notes, Retrieved 14 August, 2017, from: https://www.dxing.com/tnotes/tnote01.pdf. corps, W. (2000). FDMA vs. TDMA vs. CDMA. Connecting Wireless, Retrieved 14 August, 2017, from: https://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: https://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.