Abstract
Mobile mobile radio systems aim to provide high-mobility and powerful two-way wireless voice communications. These systems accomplish their task by integrating wireless access with large-scale networks capable of managing mobile users. Cellular radio technology generally uses the power of the transmitter at a level about 100 times that used by a cordless telephone (approximately 2 W for cell phones).
Standards
Cellular radio has been converted into digital radio technologies, using the standards of GSM systems (900 and 1800 MHz) in Europe, PDC in Japan and IS-136A and IS-95A in the United States. Third-generation systems, such as broadband code division multiple access (WCDMA) and cdma2000, are currently under development.
Design Considerations
One of the most important considerations in the design of digital systems is the high cost of cell sites. This has motivated system designers to try to maximize the number of users per megahertz, and users per cell site. Another important consideration is to maintain adequate coverage in areas of diverse terrain and population density. For example, to cover sparsely populated regions, system designers have retained the requirement for high-power transmission to provide maximum reach from the antenna locations.
Communications engineers have also been developing very small coverage areas, or microcells. Microcells provide greater capacity in areas of high user density, as well as better coverage of shaded areas. Some microcellular base stations are installed in places of high concentrations of users,
Mobile radio is a two-way communication device that operates through radio frequencies. As such, the information and message channel on a mobile radio is variable. It used to be known as radiotelephone, the previous versions of the mobile radio, were unidirectional communication systems used for the diffusion.
Contemporary mobile radio systems can have up to a hundred channels and can be controlled by microprocessors. These types require the use of software to encode channels and operate their integrated functions. The mobile radio, also known as a two-way radio system, allows the exchange of messages only with other mobile radios through PTT (push-to-talk) functions. A mobile radio also features wireless transceivers, making portable portable radios. Mobile radio systems can be used for communications on aircraft, ships, automobiles and other vehicles. The power supply on which the mobile radios work depends on the type of vehicle on which they are mounted.
A mobile radio system consists of a transceiver and a microphone with a push-to-talk key. It has an antenna that connects to the transceiver. Since most types of mobile radio are used in moving vehicles, where the surrounding noise can be loud, some types of mobile radio come with an external speaker. Other models have headphones and microphones with noise reduction capabilities.
How does a mobile radio work?
Most mobile radios operate on a single frequency band. The radio transceiver contains transmit and receive frequencies. Very high frequency (VHF) and ultra high frequency (UHF) allow a mobile radio to operate at maximum coverage. This means that its average operating range is 150 to 470 MHz.
To transmit a message, the PTT key must be pressed during the talk time to allow the voice message to be sent by the sending party. During this period, the sending party can not hear or receive any incoming mobile radio messages. Once the PTT button is released, the sender can hear the receiver's response.
Why do we need a mobile radio
The use of mobile radio in transportation, security and general operations makes communication fast, efficient and secure. It allows control centers to monitor the location of vehicles and send messages to multiple receivers simultaneously.
In addition, the scope of your area coverage is very high and does not depend on a cellular network, which may fluctuate during emergency situations.
The different types of mobile radio are portable and able to withstand severe weather and blows. Most countries impose certain requirements on the manufacture, sale and use of two-way systems. This helps to ensure that the communication gadget works according to the standards and that its use does not interfere with other communication systems.