Wireless Glossary – S

System Architecture Evolution is the core network architecture of 3GPP’s LTE wireless communication standard.

A subnetwork or special-purpose network, an SAN enables users on a larger network to attach varying data storage devices to clusters of servers.

Service Access Point is an identifying label for network endpoints used in Open Systems Interconnection (OSI) networking.

Service Access Point Identifier is an address field identifying a destination of Service Access Point.

Stop-And-Wait ARQ is a method used in telecommunications to send information between two connected devices. It ensures that information is not lost due to dropped packets and that packets are received in the correct order. It is the simplest kind of automatic repeat-request (ARQ) method. A SAW ARQ sender sends one frame at a time; it is a special case of the general sliding window protocol with both transmit and receive window sizes equal to 1. After sending each frame, the sender doesn’t send any further frames until it receives an acknowledgement signal. After receiving a good frame, the receiver sends an ACK. If the ACK does not reach the sender before a certain time, known as the timeout, the sender sends the same frame again.

Single-Carrier Frequency Division Multiple Access is a frequency-division multiple access scheme. Like other multiple access schemes (TDMA, FDMA, CDMA, OFDMA), it deals with the assignment of multiple users to a shared communication resource. SC-FDMA can be interpreted as a linearly precoded OFDMA scheme, in the sense that it has an additional DFT processing preceding the conventional OFDMA processing. Just like in OFDM, guard intervals with cyclic repetition are introduced between blocks of symbols in view to efficiently eliminate time spreading (caused by multi-path propagation) among the blocks.

A computer program that can be used to retrieve or set the IP address of a locally connected unit.

Synchronization CHannel is a downlink only control channel used in GSM cellular telephone systems. It is part of the Um air interface specification. The purpose of the SCH is to allow the mobile station (handset) to quickly identify a nearby cell (a BTS) and synchronize to that BTS’s TDMA structures.

Spatial Channel Model is a stochastic channel model for MIMO systems developed jointly by 3GPP and 3GPP2.

Stream Control Transmission Protocol is a transport layer protocol, serving in a similar role to the popular protocols Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). It provides some of the same service features of both: it is message-oriented like UDP and ensures reliable, in-sequence transport of messages with congestion control like TCP.

Secure Digital Input Output card is an extension of the SD specification to cover I/O functions.

Space-Division Multiple Access is a channel access method based on creating parallel spatial pipes next to higher capacity pipes through spatial multiplexing and/or diversity, by which it is able to offer superior performance in radio multiple access communication systems.

Service Data Unit is a unit of data that has been passed down from an OSI layer to a lower layer and that has not yet been encapsulated into a protocol data unit (PDU) by the lower layer. It is a set of data that is sent by a user of the services of a given layer, and is transmitted semantically unchanged to a peer service user.

In LTE, a Sector is a sub area of a cell. All sectors within one cell are served by the same base station. A radio link within a sector can be identified by a single logical identification belonging of that sector.

Interference with a module from another module in the same network.

The default VTP mode that allows the user to create, modify, and delete VLANS. These VLANs are saved in the VLAN database and are advertised to other switches.

The Service Area is based on the area in which a fixed network user can call a mobile user without knowing his location.

The Service Capabilities are defined by parameters, and/or mechanisms needed to realise services. These are within networks and under network control.

The Serving Network provides the user with an access to the services of home environment.

Third-from-right LED in the module. In the Access Point Module and Backhaul timing master, this LED is unused. In the operating mode for a Subscriber Module or a Backhaul timing slave, this LED flashes on and off to indicate that the module is not registered. In the aiming mode for a Subscriber Module or a Backhaul timing slave, this LED is part of a bar graph that indicates the quality of the RF link.

Software key that the SM and Bandwidth and Authentication Manager (BAM) separately calculate based on that both the authentication key (or the factory-set default key) and the random number. BAM sends the session key to the AP. Neither the subscriber nor the network operator can view this key. See also Random Number.

OSI Model Layer 5. Deals with dialog control between devices.

An interactive dialog session with a purpose of determining an initial configuration. When a startup-config is missing in NVRAM, setup mode is automatically started.

Space-Frequency Block Coding is a frequency-domain version of the Space-Time Block Codes. The family of codes is designed that the transmitted diversity streams are orthogonal and achieve the optimal Signal to Noise Ratio (SNR) with a linear receiver. Those orthogonal codes exist for the case of two transmit antennas.

Spurious-Free Dynamic Range is the strength ratio of the fundamental signal to the strongest spurious signal in the output. It is also defined as a measure used to specify analog-to-digital and digital-to-analog converters (ADCs and DACs, respectively) and radio receivers.

System Frame Number identifies the 10 ms radio frames of a cell of an eNodeB.

Short Guard Interval

Serving GPRS Support Node is responsible for the delivery of data packets from and to the mobile stations within its geographical service area. Its tasks include packet routing and transfer, mobility management (attach/detach and location management), logical link management, and authentication and charging functions.

A hashing algorithm which usees a 160-bit hash and was created to strengthen the original MD5 standard. SHA-1 was published in 1995 by the NIST.

A user or EXEC command which diplays the information of directly connected neighbors. This neighbor information such as device ID, local interface, holdtime, capability, platform, and port ID is gleaned from CDP advertisements.

The ratio, in decibels (dB), of the amplitude at the peak of the main lobe to the amplitude at the peak of a side lobe.

Short Interframe Space

Subscriber Identity Module or Subscriber Identification Module is an integrated circuit that securely stores the International Mobile Subscriber Identity (IMSI) and the related key used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers).

Single-Input Multiple-Output is a type of a transmission scheme between a transmitter with a single antenna and a receiver with multiple antennas.

Single-mode is a type of fiber cable that enables higher data rate, faster data transmission speeds, and used for longer distances than that of multi-mode fiber.

Signal to Interference plus Noise Ratio is commonly used in wireless communication as a way to measure the quality of wireless connections. Typically, the energy of a signal fades with distance. In wireless networks, this is commonly defined by path loss. SINR is calculated as SINR = P / (I + N) where P is signal power, I is interference power and N is noise power.

Selected IP Traffic Offload, H(e)NB would support Selected IP Traffic Offload to provide access for a UE connected via a H(e)NB to a IP network, e.g. Internet.

Single In Single Out

A VPN configuration that enacts a permanent or semipermanent connection between sites and directly replaces a private line connection.

Designation that defines the role of a component relative to the role of another. This designation both applies to a Backhaul slave that receives synchronization over the air from another Backhaul module (a Backhaul timing master) and applies to a redundant Bandwidth and Authentication Manager (BAM) server whose SQL database is automatically overwritten by a copy from the primary BAM server (BAM master). In each case, the slave is not a product. Rather, the slave is the role that results from deliberate configuration steps.

Cable with fibers or fiber ribbons located in grooves in the surface of the central member.

Customer premises equipment (CPE) device that extends network or Internet services by communication with an Access Point Module or an Access Point cluster.

Security Mode Command is a procedure that consists of a round-trip messages between eNodeB and User Equipment.

An Application layer protocol that supervises the network and controls configurations.

Capture of information that informs the network monitor through Simple Network Management Protocol of a monitored occurrence in the module.

Signal-to-Noise Ratio is a measure that compares the level of a desired signal to the level of background noise. It is defined as the ratio of signal power to the noise power. A ratio higher than 1:1 indicates more signal than noise.

The protocol that the Northbound Interface in Prizm uses to support integration of Prizm with an operations support systems (OSS) such as a customer relationship management (CRM), billing, or provisioning system.

Soft handover refers to a feature used by the CDMA and W-CDMA standards, where a cell phone is simultaneously connected to two or more cells (or cell sectors) during a call.

Spectral efficiency refers to the information rate that can be transmitted over a given bandwidth in a specific communication system. It is a measure of how efficiently a limited frequency spectrum is utilized by the physical layer protocol, and sometimes by the media access control (the channel access protocol).

An RF Spectrum Analyzer is a very special kind of superheterodyne receiver that receives a chosen range of signals and displays the relative signal strength on a logarithmic display, usually a cathode ray oscilloscope.

Serial Peripheral Interface bus is a synchronous serial data link standard, named by Motorola, that operates in full duplex mode. Devices communicate in master/slave mode where the master device initiates the data frame. Multiple slave devices are allowed with individual slave select (chip select) lines. Sometimes SPI is called a four-wire serial bus, contrasting with three-, two-, and one-wire serial buses. SPI is often referred to as SSI (Synchronous Serial Interface).

When dialing-in to ISDN lines, an SPID is required on occasion for billing purposes.

Permanent connection between two optical fibers that is made by fusion or bonding.

Optical component for dividing the optical power from one fiber among several other fibers.

A radio transmission technology that “spreads” the user information over a much wider bandwidth than otherwise required in order to gain benefits such as improved interference tolerance and unlicensed operation.

SQL is a Session Layer protocol that works as a query language which in turn requests, updates, and manages databases.

Signaling Radio Bearer is a radio bearer for Radio Resource Control signaling messages.

Serving Radio Network SubsystemRNS is a task of RNS to a specific connection between an User Equipment and UTRAN. There is one Serving RNS for each UE that has a connection to UTRAN.

Shuttle Radar Topography Mission

Bandwidth and Authentication Manager (BAM) interface to the SQL server. Unique sets of commands are available on this interface to manage the BAM SQL database and user access. Distinguished from Engine. See also Engine.

SSL is a protocol that offers a secure channel between two devices. SSL works at the Application layer of the OSI Model.

SSL VPN, or WebVPN, enables users to estblish connection to a VPN without requiring a client installation. This is accomplished through a secure web page.

Secondary Synchronization Signal is used by the user Equipment to detect the LTE frame timing and to get the physical layer cell identity group. It is transmitted twice in each 10 ms frame.

Wireless LAN station

Active or passive component which provides an even distribution of optical power in an identical number of incoming and outgoing fibers.

The most commonly used network design, the star topology uses a central device with separate connections to each end node, and each connection uses a separate cable. The star topology is also referred to as hub-and-spoke topology.

NVRAM stores the startup-config which is then loaded when the router or switch boots.

Assignment of Internet Protocol address that can be changed only manually. Thus static IP address assignment requires more configuration time and consumes more of the available IP addresses than DHCP address assignment does. RFC 2050 provides guidelines for the static allocation of IP addresses. See also DHCP.

An administrator manually enters the static route into the configuration, which expresses the destination network and the next hop.

Space-Time Block Code is a technique used in wireless communications to transmit multiple copies of a data stream across a number of antennas and to exploit the various received versions of the data to improve the reliability of data-transfer.

Fiber with an abrupt decrease in refractive index at the interface between core and cladding. The refractive indexes for core and cladding are constant.

Store-and-forward is a latency-varying transmission method that buffers the entire frame, calculates the CRC, and then forwards the frame.

This type of twisted-pair cabling has an extra shield that offers additional reduction of interference and/or attenuation.

STP, a Layer 2 protocol, gets rid of loops that are produced due to redundant connections on a switched network.

Stratum is a group of protocols related to one aspect of the services provided by one or several domains.

Structural element in the cable for absorbing tensile and compressive forces.

The IOS treats the subinterface, a logical extension of a physical interface, as an actual interface.

A network smaller in size that is created from a Class A, B, or C network.

A network device uses his 32-bit address to detect which piece of an IP address is the subnet portion.

The subnetting process includes chunking up a large network of IP addresses into smaller, more manageable address groups.

Preset rate limit of data transfer.

Singular Value Decomposition is a factorization of a real or complex matrix, with many useful applications in signal processing and statistics.

Created in a Layer 3 switch with the purpose of enacting inter-VLAN routing.

A bridge with multiple ports, each of which has dedicated bandwidth, that uses an ASIC to forward frames at the Data Link layer..

An as needed, on-demand virtual circuit through a service provider network.

Second-from-right LED in the module. In the Access Point Module or Backhaul timing master, as in a registered Subscriber Module or Backhaul timing slave, this LED is continuously lit to indicate the presence of sync. In the operating mode for a Subscriber Module or Backhaul timing slave, this LED flashes on and to indicate that the module is not registered. In the aiming mode for a Subscriber Module or a Backhaul timing slave, this LED is part of a bar graph that indicates the quality of the RF link.

GPS (Global Positioning System) absolute time, which is passed from one module to another. Sync enables timing that prevents modules from transmitting or receiving interference. Sync also provides correlative time stamps for troubleshooting efforts.

Radio system gain is the sum of transmitter gain plus its corresponding receiver gain. For example, a transmitter having a power output of 20 dBm combined with a receiver having a threshold sensitivity of – 80 dBm results in a radio system gain of 100 dB. Antenna System Gain: Antenna system gain is the net (combined) gain of a transmitting antenna plus the gain of a receiving antenna, minus the loss of the cables that connect the transmitter and receiver to their respective antennas. For example, at 5.8 GHz, a two-foot dish antenna has a nominal gain of 28 dBi, and low loss cable has a loss of 6 dB/100 feet. Therefore the antenna system gain for a pair of two-foot dishes and 100 feet of low-loss cable would be 50 dB (28 + 28 – 6). Total System Gain: Total system gain is the sum of antenna system gain plus radio system gain. Net System Gain: Net system gain is the amount of system gain left after the effect of free-space and all other propagation losses have been subtracted from the total system gain. The net system gain (if a positive number) is also referred to as Fade Margin.