The architecture of most cellular systems can be broken down into the following six components: a) Mobile Station (MS): A mobile station is basically a mobile or wireless device that contains a control unit, a transceiver and an antenna system for data and voice transmission. For example, in GSM networks, the mobile station will consist of the mobile equipment (ME) and the SIM card. b) Air Interface Standard: There are three main air interface protocols or standards: frequency division multiple access (FDMA), time division multiple access (TDMA) and code division multiple access (CDMA). These standards are basically the medium access control (MAC) protocols that define the rules for entities to access the communication medium. These air interface standards allow many mobile user to share simultaneously the finite amount of radio channels. c) Base Station (BS): A base station is a fixed station in a mobile cellular system used for radio communications with mobile units. They consist of radio channels and transmitter and receiver antenna mounted on a tower. d) Gateway: The gateway is the communication links between two wireless systems or between wireless and wired systems. There are two logical components inside the Gateway: mobile switching center (MSC) and interworking function (IWF). The MSC connects the cellular base stations and the mobile stations to the public switched telephone network (PSTN) or other MSC. It contains the EIR database. The IWF connects the cellular base stations and the mobile stations to internet and perform protocol translation if needed. e) Databases: Another integral component of a cellular system is the databases. There are two main databases: the Home Location Register (HLR) and Visitor Location Register (VLR). The HLR contains the information of each subscriber who resides in the same city as the mobile switching center (MSC). The VLR temporarily stores the information for each visiting subscriber in the coverage area of a MSC. The VLR is the database that supports roaming capability. f) Security Mechanism: The security mechanism is to confirm that a particular subscriber is allowed to access the network and also to authenticate the billing. There are two databases used for security mechanism: Equipment Identify Register (EIR) and Authentication Center (AuC). The EIR identifies stolen or fraudulently altered phones that transmit identity data that does not match with information contained in either the HLR or VLR. The AuC, on the other hand, manages the actual encryption and verification of each subscriber.
VHDL is basically a hardware description language. To describe hardware as a program that can be dumped into a PLD, we use VHDL. It is essential to represent hardware as program so that it can be tested before realizing it physically. If there are any errors, they can be corrected here itself.
The basic difference between fdm and fdma is that fdm is used in wired system where as fdma is used in wireless communication.
An active satellite acts as a REPEATER; it amplifies signals received and then retransmits them back to earth. This increases signal strength at the receiving terminal to a higher level than would be available from a passive satellite. A passive satellite only reflects received radio signals back to earth. fr0m: ZIA UR REHMAN D-05-ES-29 DCET Karachi Pakistan.
The basic function of a transformer is to change voltage levels.
The circuit works to put everything together. It can help to integrate all of the system so that you can have all of the things work together.
the basic service unit of cellular telephony is the cell
Cellular respiration.
The most basic feature is cellular structure.
The cellular level is the most basic level of human life. The cellular level is the beginning of structural and functional levels.
Flash software is available from the Adobe website. You have to meet basic requirements such as operating system, memory, and power to use it. Its a widely used program.
Cells are the most basic unit of organization in the body, and the cellular level is the most basic level of organization. Cells joint to for tissues, which form organs, which form organ systems, which form organisms.cell, tissue, organ, organ system, and the organism
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aerobic and anaerobic or cytoplasmic and mitochondrial
Entertech, Videoke Concerto and the Magic Sing karaoke basic system are the available option from Magic Sing karaoke. All these three types are available for purchase online.
see link below To obtain energy from food.
It involves cheese, mice, and some aerosol products.
Newtons is the basic metric system unit for weight