Wireless Systems

wireless systems AMPS Advanced Mobile Phone Service. The analog wireless transmission standard (technology) deployed in the 1980s in the United States and Canada. AMPS operates at 800 MHz. Blue Tooth Blue Tooth is an exciting new technology that allows devices such as mobile phones, Lap Top computers, digital cameras, personal digital assistants (PDAS), and other portable devices to communicate with each other without using cables to connect them. Blue Tooth is. a technology that allows these devices to communicate with each other using short-range radio waves CDMA Code Division Multiple Access (CDMA) is one of the several digital wireless transmission methods in which signals are encoded using random sequence which corresponds to a different communication channel that the receiver also knows and can use to decode the received signal. CDMA is one of several "spread spectrum" techniques. CDMA offers improvements over analog transmission in the areas of reduced call dropping battery Power conservation, more secure transmission and increased service options. CDPD Cellular Digitai Packet Data (CDPD) is a specification for supporting wireless access to the Internet and other public packet-switched networks. Cellular telephone and modem providers that offer CDPD support make it possible for mobile users to get access to the Internet at up to 19.2 Kbps. Because CDPD is an open specification that adheres to the layered structure of the Open Systems Interconnection (OSI) model, it has the ability to be extended in the future. CDPD Supports both the Internet's IP protocol and the 1S0 Connectionless Network Protocol (CLNP). Cell The geographic area encompassing the signal range from one base station (a site containing a radio transmitter/receiver and network communication equipment). Wireless transmission networks are comprised of many hexagonal, overlapping cell sites to efficiently use radio spectrum for wireless transmissions. Also, the basis for the term "cellular phone." Cellular In wireless communications, cellular refers most basically to the structure of the wireless transmission networks which are comprised of cells or transmission sites. Cellular is also the name of the wireless telephone system originally developed by Bell Laboratories that used low-powered analog radio equipment to transmit within cells. The terms "cellular phone" or "cell phone" are used interchangeably to refer to wireless phones. Within the wireless industry, cellular is also used to refer to non-PCS products and services. FDMA Frequency Division Multiple Access (FDMA) is the division of the frequency band allocated for wireless cellular communication into 30 channels, each of which can carry a voice conversation or, with digital service, carry digital data. FDMA is a basic technology in the analog Advanced Mobile Phone Service (AMPS), the most widely-installed cellular phone system installed in North America. With FDMA, each channel can be assigned to only one user data time. FDMA is also used in the Total Access Communication System (TACS). GEO Geosynchronous Earth Orbit (GEO). A term for a satellite which is placed in a geosynchronous, or geostationary orbital slot. Such orbits are always equatorial; the satellites are placed at altitudes of approximately 22,300 miles. As a result, they are synchronized with the rotation of the earth, maintaining their relative position to the earth's surface. In other words, they always appear to be in the same spot. GPS Global Positioning System (GPS). A system to allow us all to figure out precisely where we are anywhere on earth. The GPS will eventually consist of a constellation of 21 satellites orbiting the earth at 10,900 miles they circle the earth twice a day. In a way you can think of them as "man-made stars" to replace the stars that we've traditionally used for navigation. GSM Global System for Mobile Communications (GSM) is the digital transmission technique widely adopted in Europe and supported in North America for PCS. GSM uses the 1900 MHz. GSM uses 900 MHz and 1800 MHz in Europe. LEO Low Earth Orbit Satellites (LEO). Also called LEOS, as in Low Earth Orbiting Satellites. Low Earth Orbit Satellites move a few hundred miles in orbit around the earth in various orbits like electrons whizzing around the nucleus of an atom. A group of such satellites is known as a constellation. To establish a connection, you gain access to one of these satellites much as you gain access to a cell site in close proximity in the case of cellular telephony. When that satellite moves out of range, you are handed off to another satellite which has come into view. MEO Middle Earth Orbiting satellite (MEO). MEOS operate much like LEOS, although in slightly higher orbits. MEOS are capable of supporting both voice and data services. Mobile Phone A term often used interchangeably with cellular phone or wireless phone. Initially, a mobile phone referred to a phone attached to a vehicle, the vehicle's battery and had an external antenna. Mobile phones were distinguished from transportable, portable, cordless and personal phones. MTSO Mobile Telephone Switching Office (MTSO) connects the cellular network to the public switched telephone network. N-AMPS (Narrowband AMPS) transmission standard with digital signaling information to effectively triple the Narrowband Advanced Mobile Phone Service. Combines the AMPS capacity of AMPS while adding basic messaging functionality. PCS Personal Communications Service (or System). Generally, a marketing term used to describe a wide variety of two-way digital wireless service offerings operating at 1900 MHz. PCS services include next generation wireless phone and communication services, wireless communications service with lightweight, lowpowered handsets, in-building cordless voice services for business, in-building wireless LAN service for business, enhanced paging service as well as wireless services integrated with wired networks. A personal communications System refers to the hardware and software that provide communications services. Point to Point A private circuit, conversation or teleconference in which there is one person at each end, usually connected by some dedicated transmission line. In short, a connection with only two end points. Point to Multipoint A circuit by which a single signal goes from one origination point to many destination points. TDMA digital wireless transmissions that increases the efficiency of the network by Time Division Multiple Access is one of several technologies used in allowing a greater number of simultaneous transmissions. Networks using TDMA assign 6 time slots for each frequency channel. Devices using the wireless network send bursts of information that are reassembled at the receiving end. Third Generation (3G) The 3rd Generation (3G) mobile devices and services will transform wireless communications into on-line, real-time transfer of information, regardless of time and place. You will be able to send electronic postcards with images, and you can even have a live video conference using your 3G mobile communication device. WAP Wireless Application Protocol (WAP) is a protocol developed to allow intelligent transmission of optimized Internet content to wireless phones. Wireless Wireless means without wires. Communication without any physical connections between the sender and the receiver. Using the radio frequency spectrum (airways) and hardware, software and technologies to transmit information.