Draw the general view of telecommunication and explain the function of the each unit?
February 26, 2024
1. Draw the general view of telecommunication and explain the function of the each unit?
The general view of the cellular system is shown in Fig.1.
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| A general view of cellular telecommunications system |
Antenna:
Antenna pattern, antenna gain, antenna tilting, and antenna height 6 all affect the cellular system design. The antenna pattern can be omnidirectional, directional, or any shape in both the vertical and the horizon planes. Antenna gain compensates for the transmitted power. Different antenna patterns and antenna gains at the cell site and at the mobile units would affect the system performance and so must be considered in the system design. The antenna patterns seen in cellular systems are different from the patterns seen in free space. If a mobile unit travels around a cell site in areas with many buildings, the omnidirectional antenna will not duplicate the omni pattern. In addition, if the front-to-back ratio of a directional antenna is found to be 20 dB in free space, it will be only 10 dB at the cell site. Antenna tilting can reduce the interference to the neighboring cells and enhance the weak spots in the cell. Also, the height of the cell site antenna can affect the area and shape of the coverage in the system.Switching Equipment:
The capacity of switching equipment in cellular systems is not based on the number of switch ports but on the capacity of the processor associated with the switches. In a big cellular system, this processor should be large. Also, because cellular systems are unlike other systems, it is important to consider when the switching equipment would reach the maximum capacity. The service life of the switching equipment is not determined by the life cycle of the equipment but by how long it takes to reach its full capacity. If the switching equipment is designed in modules, or as distributed switches, more modules can be added to increase the capacity of the equipment. For decentralised systems, digital switches may be more suitable.The future trend seems to be the utilisation of system hand off. This means that switching equipment can link to other switching equipment so that a call can be carried from one system to another system without the call being dropped.
Data Links:
The data links are shown in Fig 1. Although they are not directly affected by the cellular system, they are important in the system. Each data link can carry multiple channel data (10 kbps data transmitted per channel) from the cell site to the MTSO. This fast-speed data transmission cannot be passed through a regular telephone line. Therefore, data bank devices are needed. They can be multiplexed, many-data
channels passing through a wide band T-carrier wire line or going through a microwave radio link where the frequency is much higher than 850 MHz. Leasing T-carrier wire lines through telephone companies can be costly. Although the use of microwaves may be a long-term money saver, the availability of the microwave link has to be considered.
channels passing through a wide band T-carrier wire line or going through a microwave radio link where the frequency is much higher than 850 MHz. Leasing T-carrier wire lines through telephone companies can be costly. Although the use of microwaves may be a long-term money saver, the availability of the microwave link has to be considered.
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