what is WCDMA netwok?

W-CDMA/UMTS

Wideband CDMA is a 3G wireless standard which allows use of both voice & data and offers data speeds of up to 384 Kbps.
WCDMA is also called UMTS (Universal Mobile Telecommunications System) and the two terms have become interchangeable.
UMTS is a third generation mobile cellular system for networks based on the GSM standard, developed and maintained by the 3GPP (3rd Generation Partnership Project)
W-CDMA uses the DS-CDMA channel access method with a pair of 5 MHz wide channels.

WCDMA

The specific frequency bands originally defined by the UMTS standard are 1885–2025 MHz for the base-to-mobile (uplink) and 2110–2200 MHz for the mobile-to-base (downlink).

In the US, 1710–1755 MHz and 2110–2155 MHz are used instead, as the 1900 MHz band was already used.

Architecture of UMTS Network

As shown in the figure there are three main components in UMTS network architecture.
User Equipments is composed of Mobile Equipment (ME) and USIM.
Radio Access Network is composed of NodeB and RNC.
Core Network is composed of circuit switched and packet switched functional modules.
For Circuit switched (CS) operations MSC and GMSC along with database modules such as VLR, HLR will be available.
For packet switched (PS) operations SGSN and GGSN will serve the purpose.
GMSC will be connected with PSTN/ISDN in CS case.
GGSN is connected with Packet data Network (PDN) for PS case.

HSPA

High Speed Packet Access (HSPA) is an combination of two mobile protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performance of existing 3G mobile telecommunication networks using the WCDMA protocols.
The system provides an enhancement on the basic 3G WCDMA / UMTS cellular system, providing much greater data transfer rates.
The system provides many advantages for users over the original UMTS system

The two technologies are summarised below

HSDPA - High Speed Downlink Packet Access: HSDPA provides packet data support, reduced delays, and a peak raw data rate (i.e. over the air) of 14 Mbps. It also provides around three times the capacity of the 3G UMTS technology defined in Release 99 of the 3GPP UMTS standard.

HSUPA - High Speed Uplink Packet Access: HSUPA provides improved uplink packet support, reduced delays and a peak raw data rate of 5.74 Mbps. This results in a capacity increase of around twice that provided by the Release 99 services.

LTE (Long Term Evolution)

In telecommunications, Long-Term Evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA technologies.

LTE Architecture

The high-level network architecture of LTE is comprised of following three main components:
The User Equipment (UE).
The Evolved UMTS Terrestrial Radio Access Network (E-UTRAN).
The Evolved Packet Core (EPC).
The E-UTRAN handles the radio communications between the mobile and the evolved packet core and just has one component, the evolved base stations, called eNodeB or eNB.
Each eNB is a base station that controls the mobiles in one or more cells. The base station that is communicating with a mobile is known as its serving eNB.
LTE Mobile communicates with just one base station and one cell at a time and there are following two main functions supported by eNB:
The eBN sends and receives radio transmissions to all the mobiles using the analogue and digital signal processing functions of the LTE air interface.
The eNB controls the low-level operation of all its mobiles, by sending them signalling messages such as handover commands.
EPC (Evolved Packet Core) contains information about all the network operator's subscribers, communicates with the outside world, forward the data b/w base station & gateways