Universal Mobile Telecommunication System UMTS Architecture
Universal Mobile Telecommunication System (UMTS), as example of 3G mobile communication systems is going to repeat success of Global Standard for Mobile communication (GSM). UMTS is on the edge of commercial deployment and first commercial network has already started its operation in Japan. This thesis gives overview out of the UMTS emphasising to functionality of Radio Resource Management (RRM) of UMTS Terrestrial Radio Access Network (UTRAN). Operation of the radio interfaces is explained, but the main subject of the thesis is anyhow radio resource management across UMTS radio network subsystems. RRM is set of procedures, which affect through the whole structure of the UTRAN. It is very important to reach right behaviour of the RRM functionality for the distribution resources of the network and providing the best services to end-user. The RRM concept and number of procedures are explained in details in this thesis. Radio Network Subsystem Application Part (RNSAP) is studied in this thesis, as example of protocol involved in RRM process.
Keywords: mobile communications, UMTS, signalling protocol, Radio Network Subsystem Application Part , RNSAP.
The UMTS (Universal Mobile Telecommunication System) is example of the 3G systems. Some parts of 3G will mostly be based on GSM technical solutions.
2 One of the main requirement for the 3G standardization is generic radio access in 3G, which makes possible high bit rates up to 2 Mbps (Mega Bits Per Second).
The 3G systems start to use new air interface with CDMA or WCDMA (wideband CDMA)technology. The CDMA makes possible to obtain variable bit rate, depending on the user
requirements. In the CDMA, it is easy to assign different bit rates for uplink and downlink transmissions for each user. Therefore, CDMA supports asymmetric communications such
as TCP/IP access. The wide bandwidth of WCDMA enables the provision of highertransmission rates. Additionally, it makes possible to provide low and high rate services in
the same band. The wider band carrier of the WCDMA system helps to increase the number of channels/users in one carrier. The statistical multiplexing effect will help in
increasing the frequency usage efficiency. This efficiency drops in narrow-band systems with fast data communications, because the number of users on one carrier is limited.
The 3G systems multiplex services with different QoS (Quality Of Services) requirements on a single connection due to new structure of the RAN (Radio Access
Network). It makes possible to use radio spectrum very efficiency in combination with new transport technologies, such as ATM (Asynchronous Transfer Mode) or IPv6. These new
features allow UMTS to provide new services with high QoS, which corresponds new generation of user requirements.
Present Master’s Thesis contains theoretical and practical parts. The main emphases of the theoretical part are at the new interface Iur, which is provided by UMTS
for the radio resource management across radio network subsystems. Thesis is based at the work, which is done for the 3G SDL Library Project ongoing in Nokia Research Center.
The practical part of the Thesis describes implementation of the Radio Network Subsystem Application Part protocol, as example of the UMTS signalling protocol, which is involved
in the radio resource management in the UMTS.