User`s guide

EXPANSION PORT MOUNTING
7
2.2. UMTS technology
For radio terrestrial part UMTS (Universal Mobile Telecommunication System), which is
marked as UTRA (UMTS Terrestrial Radio Access), is warranted 155 MHz band in frequency
band about the 2 GHz. It is bands 1900–1980 MHz, 2010–2025 MHz and 2110–2170 MHz.
The UMTS system is based on code division of carried channels – use the access
method WCDMA (Wideband Code Division Multiple Access). WCDMA exploits direct spread
spectrum DS (Direct Spread). For transmission the UMTS network exploits two duplex
techniques – transmission modes FDD (Frequency Division Duplex), which is based
on separate frequency channels (i.e. uplink and downlink uses different channels) and TDD
(Time Division Duplex), which is based on separate time (i.e. uplink and downlink uses one
channel, in which both directions are changes in time).
UMTS network consists of three basic entities:
• Basic network CN (Core Network) – own core of network UMTS,
• network UTRAN (UMTS Terrestrial Radio Access Network) – the radio access
network,
• users part UE (User Equipment) – entity, which allows the user to access
the UMTS network.
2.3. HSDPA technology (High Speed Download Packet Access)
HSDPA is an improved and extended version of the UMTS-TDD. HSDPA is available
for both UMTS FDD and for UMTS TDD. HSDPA raises significantly bit rate for downlink. It is
attained on the programmer level. It doubles capacity on BTS (Base Transceiver Station),
which allows process of data and signals from more users at one time. HSDPA is based
on a few innovations of network architecture; thanks to this, it has lower latency, faster
reaction on channel change quality and processing of H-ARQ (Hybrid automatic repeat
request) on transmission repeat. Transport channel for HSDPA effectively uses available
frequencies, on which transmits data packets together. Afterwards these packets are divided
between individual users according to specific algorithms.