Wideband code division multiple Access (WCDMA)
After the introduction of third-generation and advanced generation techniques, many advanced features were been provided to users along with typical voice calling and texting options available in old 2G technology networks. New features were possible by the utilization of advanced wireless communication technologies. These modern technologies enabled the facilitation of both voice and data applications using the same previous setup with few modifications to support packet data along with circuit switching for voice call and internet-related applications. One of these modern techniques is a wideband code division multiple access (WCDMA), which has the capability of providing multiple users with wireless access of the same network while providing the facility of high data rates.
Major parts of the WCDMA interface are core network (CN), Radio network controller (RNC), node B and user equipment (UE).
The user equipment is nothing but a smart mobile phone device, which now has an extra feature of data requests i.e. internet access and GSM support. Node B is similar to the BTS towers in old 2G technologies. The entire physical layer processing such as error correction/detection, modulation, and wireless transmission/reception handling is been performed by the nodeB. Multiple nodeB’s are been connected to a radio network controller (RNC).
RNC is responsible for call setup, and for the radio resource management among different nodeB’s. For example, if UE requests from one of the NodeB’s is higher than RNC will automatically provide more resources to that node in order to accommodate all the requests from different UE’s.
There could be multiple RNC’s in a network, but all of them will have wireless links with each other and also the link to the core network (CN) for the communication between RNC’s and CN. When a UE makes some request of voice calling to some other UE by communicating with NodeB, that request is transferred to the associated RNC, which is responsible for call setup and resource management. RNC will analyze the request and then will connect the user with the core network. The Core network forwards the request to the voice network or internet network by switching between them, depending upon the nature of the request. So WCDMA is a wireless air interface providing a link to both voice and data communication.
WCDMA interface can be employed for different kinds of wireless access network applications involving different UE’s such as laptops and other smart devices. However, it is most commonly deployed in Universal Mobile Telecommunications System (UTMS).
The Block diagram of UTMS is shown in figure 2, which is similar to the WCDMA block diagram. UTMS is nothing but an advanced version of the old cellular network system of the 2G network with the additional support of packet data. As third-generation telecommunication systems also require facilitation of both voice and packet data switching. Mostly, the radio network subsystem (RNS) in UTMS is WCDMA based air interface. However, it can also be based on some different air interfacing with the ultimate goal of providing a link to both voice and packet data.