Principles of Mobile Communication †Free Samples to Students

Question: Discuss about the Principles of Mobile Communication. Answer: Introduction: Spread spectrum is defined as a technique of broadcasting radio signals. It is therefore used to spread particular telecommunication signals. In spread spectrum, the telecommunication signal is broadcasted in a particular bandwidth which is considerably greater in terms of frequency of the original data. The signal transmitted is much higher than the original signal and conventional modulation methods are used in transmission of a signal in spread spectrum. Spread spectrum is a process that is mainly used in radio transmission and is based in the concept of manipulation of a narrow band signal before its transmission. In spread spectrum communication, the bandwidth occupancy of a signal is greater in comparison to the system that makes use of the conventional modulation methods (Nintanavongsa et al., 2012). In spread spectrum the transmitted signal frequency is varied. This results in much use of a much greater bandwidth in the signal than it would have generally possessed if the signal was not varied. It is therefore a practice of spreading a transmitted signal in occupying a particular frequency spectrum that is available for transmission. The spread spectrum technology can therefore be implemented with a frequency hopping technique as in frequency hopping; the signal is generally transmitted in short bursts. Spread spectrum finds its usage in cellular telecommunication (Stber, 2017). The different spread spectrum transmission processes include frequency hopping spread spectrum, direct sequence spread spectrum and time hopping spread spectrum. Direct sequence is used where there is a need to reduce the signal interference. Frequency hopping spread spectrum on the other hand is used for broadcasting radio signals, which is done by rapid switching of the carrier among the different frequency channels. This includes the use of a pseudorandom sequence that is known both to the transmitter and the receiver. Time hopping spread spectrum is a method of spread spectrum where time is changed in a random manner. It makes use of pseudo random sequence as well. The two most commonly used spread spectrum techniques are direct sequence and frequency hopping. The comparison between these two methods of spread spectrum is as follows- Direct Sequence Spread Spectrum Frequency Hopping Spread Spectrum It makes use of a fixed carrier. Makes use of a radio carrier that hops from one frequency to another in a known pattern and the pattern. The set data signal is spread to a much larger range of frequencies by making use of a specific encoding scheme (Xuan Quyen, Van Yem Manh Hoang, 2013). A particular bandwidth spectrum is segregated into different broadcast frequencies (Torrieri, 2015). Frequency remains constant in DSSS Frequencies are randomize in frequency hopping spread spectrum (FHSS) Data are randomized in DSSS Data remains constant in FHSS It is not resistant to noise It is resistant to noise Offers much higher throughput Offers limited throughput Performance level is better and more reliable Use less power but performance level is low Table 1: Representing the Differences between DSSS and FHSS The major two components of a radio system is Radio transmitter and radio receiver. There are different sub parts of radio transmitter and the radio receiver. The sub parts of radio transmitter are power supply, oscillator, modulator, Amplifier and an antenna. The different subcomponents of radio receivers are antenna, RF amplifier, Tuner, detector and audio amplifier. Mixers can be defined as the equipment that arranges multiple audio signals in a balanced way. The main functionality of mixer is to adjust the tone quality is such a way that it becomes easier for the audiences to listen to audio. Mixers can be broadly classified into three types, which are analog mixers, Digital mixers and powered mixers. Analog Mixers The analog mixers find its use in adjustment of volume and tone of an input signal. In this type of mixer, the control knobs and the faders are present on the top panel. Operating analog mixers can be described as an intuitive process as it makes it easier for the signal flow and the state of the audio. Digital Mixers can be defined as the process where audio signal acts as input and adjust the tone of the audio signal by making use of a digital signal processing technology. One of the main functionalities of digital mixer is that, it can store the position of the faders and the knobs, and is able to recall it in an instant. There are various functions of the knobs and the faders to keep the unit compact. However, digital mixer is very complex to set up but provides greater functionality in comparison to analog mixer. Powered mixers are a type of analog mixer that posses a built in power amplifier. This provides the functionality of connecting the mixers directly with the speakers. Therefore, the powered mixer makes the operation of the mixers even more simplified. Cellular antennas are an integral part of the telecommunication system and are used all over the world. Therefore, it is expected to remain dominate in future. GiFi is a new technology and therefore, further research is needed in this field. However, it is capable of revolutionizing the field of wireless networks. References Bernardos, C. J., De La Oliva, A., Serrano, P., Banchs, A., Contreras, L. M., Jin, H., Ziga, J. C. (2014). An architecture for software defined wireless networking. IEEE wireless communications, 21(3), 52-61. Bilotti, F., Di Palma, L., Ramaccia, D., Toscano, A. (2012). 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Design optimization and implementation for RF energy harvesting circuits.IEEE Journal on emerging and selected topics in circuits and systems,2(1), 24-33. Stber, G. L. (2017).Principles of mobile communication(Vol. 3). Springer. Torrieri, D. (2015).Principles of spread-spectrum communication systems. Springer. Xuan Quyen, N., Van Yem, V., Manh Hoang, T. (2013). A chaos-based secure direct-sequence/spread-spectrum communication system. InAbstract and applied analysis(Vol. 2013). Hindawi.