T-V

time difference of arrival (TDOA)

TDOA is a wireless location determination technology that relies on measuring difference in the time between when a signal is received.

Time Division Multiple Access (TDMA)

TDMA is an older form of cellular access technology. Telephone conversations are kept orthogonal by dividing access to a common frequency channel into timeslots and allocating each conversation its own timeslot. Each timeslot provides exclusive access to the channel frequency but only for a very short period of time.

Timing Advance (TA)

In GSM networks, TA is a measure of the timing difference between MS and BTS; a location measurement.

Transmission Control Protocol (TCP)

TCP is a reliable, connection-oriented, streaming protocol that is widely used on the Internet.

Transport Layer Security (TLS)

TLS is a protocol based on TCP that provides security through a range of cryptographic methods. It offers features that allow for authentication, data privacy, protection against forgery, and data integrity. TLS is the successor to Secure Sockets Layer (SSL).

Trusted-Party Query (TPQ)

A trusted-party query is made against an LIS by a privileged node inside the access network and is used to retrieve location information about Targets that are unable to provide location for themselves.

uncertainty

Uncertainty is an area or volume where a particular target could be found that reflects the inherent variation in the location determination method.

See also confidence.

Uniform Resource Identifier (URI)

A URI is an addressing scheme that can be used to refer to resources, either a document or network location (for a URL); or a concept or other identifier (for a URN).

Uniform Resource Location (URL)

See Uniform Resource Identifier (URI).

Uniform Resource Name (URN)

See Uniform Resource Identifier (URI).

Universal Mobile Telecommunications System (UMTS)

UMTS is the 3GPP third-generation wireless standard.

Universal Plug and Play (UPnP)

UPnP is a suite of standards that enable discovery, configuration, and control of IP devices. These are typically devices used in the home, including routers and other appliances.

Uplink TDOA (U-TDOA)

U-TDOA is a TDOA technology that observes the time difference in a signal sent from a target device at several fixed points in the network.

User Agent (UA)

In SIP, the UA refers to an end-point in a transaction or dialog.

User Datagram Protocol (UDP)

UDP is the datagram, best-effort protocol in the IP suite.

User Equipment (UE)

In 3GPP, the UE is the mobile device-a generic name that covers the wide array of devices that can be connected to these networks.

Virtual Circuit (VC)

Because ATM frames are too small to include unique node addresses, ATM relies on the establishment of a virtual circuit for the routing of messages.

Virtual Circuit Identifier (VCI)

The VCI is part of the addressing information used in an ATM frame that identifies a particular virtual circuit.

Virtual LAN (VLAN)

In Ethernet, a virtual LAN can be established on a switch to effectively split the switch into two or more logical devices.

Virtual Path Identifier (VPI)

The VPI is part of the addressing information used in an ATM frame that identifies a particular virtual path.

virtual private network (VPN)

A VPN is a network extension that uses security and tunneling protocols to, in effect, establish a separate network that operates on top of another network. This is frequently used to provide remote access to enterprise networks.

Voice over Internet Protocol (VoIP)

VoIP is a generic term used to refer to technologies that carry voice traffic over the Internet.

Voice Service Provider (VSP)

A VSP is a provider of a voice service. This includes a registrar, call server, and possibly a PSTN gateway service.

VoIP Position Center (VPC)

The VPC is the node responsible for providing routing information based on location information in the NENA i2 standard. The VPC is also responsible for making location information available to the PSAP over VE2 interface.