| SGSN: Serving GPRS Support Node |
The Serving GPRS Support Node (SGSN) is the node which, in some sense, carries out the same function as the Local Agent in Mobile IP. However, an SGSN is actually considerably more complex since it also does the full set of interworking with the connected radio network. This means that the functions carried out by the SGSN vary quite considerably between GSM and UMTS.
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| Shadow fading |
Shadow fading is a phenomenon that occurs when a mobile moves behind an obstruction and experiences a significant reduction in signal power.
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| SHF: Super High Frequency |
Super High Frequency (SHF) is the RF spectrum between 3 GHz and 30 GHz.
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| SHO: Soft Handoff |
Soft Handoff (SHO) refers to two base stations -- one in the cell site where the phone is located and the other in the cell site to which the conversation is being passed, but both are held on the call until the handoff is completed. The first cell site does not cut off the conversation until it receives information that the second is maintaining the call.
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| SiGe: Silicon-Germanium Technology |
Silicon-Germanium Technology (SiGe) makes it possible to design complex chips that integrate the functions of a cellular telephone, an e-mailbox and an Internet browser into a handheld information device with rapid data-transfer capability.
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| Signal Booster |
Signal Booster compensates for loss of effect (weakening of the signal in the coaxial cable) between the outer antenna and the phone. It can apply to both incoming and outgoing signals.
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| Signal Strength |
Signal Strength is the strength of the radio waves in a wireless network.
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| Silent Alert |
Silent Alert is the non-audible signal in a beeper, which discretely notifies individuals of incoming pages, typically by vibration.
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| SIM: Subscriber Identity Module |
Subscriber Identity Module (SIM) is a component of a Mobile System (MS) in a GSM network that contains all the subscriber information.
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| SIMO: Single Input Multiple Output |
Single Input Multiple Output (SIMO) is a form of smart antenna technology for wireless communications in which a single antenna at the transmitter and multiple antennas are used at the destination (receiver). An early form of SIMO, known as diversity reception, has been used by military, commercial, amateur, and shortwave radio operators at frequencies below 30 MHz since the First World War. The other forms of smart antenna technology include Single Input Single Output(SISO), Multiple Input Multiple Output (MIMO) and Multiple Input Single Output (MISO).
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| Simulcast |
Simulcast refers to broadcasting a message over multiple transmitters throughout a geographical region at precisely the same time.
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| SINR: Signal to Interference plus Noise |
Signal to Interference plus Noise Ratio (SINR) is the ratio of the received strength of the desired signal to the received strength of undesired signals (noise and interference).
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| SISO: Single Input Single Output |
Single Input Single Output (SISO) is a form of antenna technology for wireless communications in which a single antenna at both the transmitter and at the destination (receiver) are used.
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| Site survey |
Site survey is a survey conducted at the location for a new WLAN in an effort to avoid what could be time-consuming and costly problems down the road. It involves diagramming the network, checking the building and testing the equipment.
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| SLF: Subscription Locator Function |
Subscription Locator Function (SLF), a component in the IP Multimedia Subsystem (IMS), locates the database containing subscriber data in response to queries from the I-CSCF (Interrogating-Call Session Control Functions) or application server (AS).
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| Slotted ALOHA |
Slotted ALOHA is an access technique synchronizing the transmitters to time-slots in the channel and having the transmitter wait until the next available slot to send its packet.
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| Slow fading |
Slow fading is a long-term fading effect changing the mean value of the received signal. Slow fading is usually associated with moving away from the transmitter and experiencing the expected reduction in signal strength.
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| SM: Spatial Multiplexing |
Spatial Multiplexing (SM) is a transmission technology developed by Stanford University and Iospan Wireless in California exploiting multiple antennas at both the BS and CPE to dramatically increase the bit rate in a wireless radio link with no additional power or bandwidth consumption. Under certain conditions, SM offers linear increase in spectrum efficiency with the number of antennas.
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| Smart phone |
Smart phone is a wireless phone with text and Internet capabilities. Smart phones can handle wireless phone calls, hold addresses and take voice mail and can also access information on the Internet and send and receive e-mail and fax transmissions.
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| SMATV: Satellite Master Antenna Televisi |
Satellite Master Antenna Television (SMATV) refers to the transmission of television programming to a Satellite Master Antenna installed on top of an apartment building, a hotel, or at another central location from where it serves a private group of viewers. The transmission usually is done in C-band to 1.5 or 2 meter dishes.
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| SMG: Special Mobile Group |
Special Mobile Group (SMG) is a standards body within ETSI that develops specifications related to mobile networking technologies, such as GSM and GPRS.
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| SMLC: Serving Mobile Location Center |
Serving Mobile Location Center (SMLC), either a separate network element or integrated functionality in the Base Station Controller(BSC), contains the functionality required to support Location Services (LCS). The SMLC manages the overall coordination and scheduling of resources required for the location of a mobile unit. The SMLC may control a number of Location Measurement Unit (LMU) for the purpose of obtaining radio interface measurements to locate or help locate Mobile Station (MS) subscribers in the area that it serves.
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| SMLCPP: Serving Mobile Location Center P |
Serving Mobile Location Center Peer-to-Peer Protocol (SMLCPP) is a transport protocol for the communication between the Serving Mobile Location Centers (SMLCs). The main functions of SMLCPP are: (1) allowing an SMLC to ask for and obtain information about Radio Interface Timing (RIT), as known from measurements done by LMUs not under its direct control; (2) allowing an SMLC, that controls deciphering keys in the location area, to sent them to other SMLCs in the same location area.
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| SMPP: Short Message Peer to Peer |
Short Message Peer to Peer (SMPP) is a protocol for exchange short messages between SMS peer entities such as short message service centers. SMPP is often used to allow third parties (e.g. value-added service providers like news organisations) to submit messages, often in bulk.
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| SMR: Specialized Mobile Radio |
Specialized Mobile Radio (SMR) is a dispatch radio and interconnect service for businesses, covering frequencies in the 220 MHz, 800 MHz and 900 MHz bands.
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