, an acronym for Universal Mobile Telecommunications System (UMTS) - time-division duplexing (TDD)
, is a 3GPP standardized
version of UMTS
networks that use UTRA-TDD
. UTRA-TDD is a UTRA
that uses time-division duplexing
. While a full implementation of UMTS, it is mainly used to provide Internet access in circumstances similar to those where WiMAX
might be used. UMTS-TDD is not directly compatible with UMTS: a device designed to use one standard cannot, unless specifically designed to, work on the other, because of the difference in air interface technologies and frequencies used.
UTRA-TDD HCR is one of the air interfaces used for UMTS-TDD. It uses increments of 5 MHz of spectrum, with each slice divided into 10ms frames containing fifteen time slots (1500 per second). The time slots are allocated in fixed percentage for downlink and uplink. TD-CDMA
is used to multiplex streams from or to multiple transceivers.
UTRA-TDD LCR is an alternative air interface used for UMTS-TDD. It is based on TD-SCDMA
, and uses 1.6 MHz slices of spectrum, and is standardized in UMTS by the 3GPP.
In Europe, CEPT
allocated the 2010-2020 MHz range for a variant of UMTS-TDD designed for unlicensed, self-provided use. Some telecom groups and jurisdictions have proposed... Read More