Universal Access (UA)
The availability, within a defined reasonable travel time, of shared access points to Universal Services (such as payphones, telecentres, etc.) 

Universal Provision
The inclusion of both Universal Service and Universal Access.

Universal Service (US)
The availability of a Telecommunications Service at the consumer’s premises, or to him/her personally on a full-time basis. 

Ubiquitous computing
A term that reflects the view that future communication networks will allow seamless access to data, regardless of where the user is.

UDP
User datagram protocol.

UHF
Ultra high frequency (698-806/ 862 MHz).

ULL
Unbundled local loop. See LLU.

UMB
Ultra-mobile broadband.

UMTS
Universal mobile telecommunications system.
The European term for thirdgeneration mobile cellular systems or IMT-2000 based on the W-CDMA standard. For more information, see the UMTS Forum website at: www.umts-forum.org

UN
United Nations.

Underlay spectrum sharing


Unicast
A transmission between a single sender and a single receiver over a network. See also Multicast and Broadcast.

Universal access
Refers to reasonable telecommunication access for all. Includes universal service for those that can afford individual telephone or other ICT service and widespread provision of public access to ICTs (i.e., telecentres, cybercafés, etc.) within a reasonable distance.

USD
United States dollar.

USO
Universal service obligations.
Requirements that governments place on operators to offer service in all areas, regardless of economic feasibility.

UTRAN
UMTS Terrestrial Radio Access Network.

UWB
Ultra-wideband.