This question appears in Mumbai University > Wireless Networks subject

Marks: 10 M

Year: May 2012

i. Universal mobile telecommunications services (UMTS) is based on 5 MHz WCDMA and optimized for efficient support of 3G services in the GSM technology. UMTS can be used in existing spectra for GSM as well as in the additional new spectra for GSM.

ii. UMTS will provide access at up to 2 Mbps in the local area and less than 1 Mbps wide-area access with full mobility.

iii. The term UMTS includes all aspects of the system, including the physical layer, network planning and architecture, protocols, services and applications.

1. UMTS Releases

i. The initial release of UMTS standards was referred to as release 99 or R99. This (release) aimed at a cost-effective migration from GSM to UMTS.

ii. After R99 the release of 2000 or R00 followed. 3GPP decided to split R00 into two standards and called them release 4 (Rel-4) and release 5 (Rel-5). The version of all standards finalized for R99 was then referred to as Rel-3 by 3GPP.

iii. Rel-4 introduced QoS in the fixed network, execution environments (e.g., MExE, mobile execution environment) and new service architectures. Rel-4 was suspended in March 2001.

iv. Rel-5 specified a new core network replacing the GSM/GPRS-based core network by an almost all-IP core network. The content of Rel-5 was suspended in March 2002. This standard integrated IP-based multimedia services (IMS) controlled by the IETF’s session initiation protocol (SIP). A high-speed downlink packet access (HSDPA) service with 8 to 10 Mbps was included. Also, a wideband 16 kHz adaptive multirate (AMR) codec was added for better quality. End-to-end QoS and several data compression techniques were added.

v. Rel-6 standard aimed at including multiple input multiple output (MIMO) antennas, enhanced multimedia service (MMS), security enhancement, WLAN/WWAN interworking, broadcast/multicast services, enhanced IMS, IP emergency call, and many more management features.

vi. Almost each year, a new release of UMTS standard is published.

2. UMTS Technology

i. UMTS provides backward compatibility with GSM in terms of network protocols and interfaces (MAP, ISUP (ISDN user part), etc.) The core network supports both GSM and UMTS/IMT-2000 services, including handoff and roaming between the two.

ii. The proposed W-CDMA based UMTS terrestrial radio access network (UTRAN) is connected to the GSM-UMTS core network using a new multi-vendor interface (Iu).

iii. The transport protocol within the new radio network and the core network will be IP.

iv. Like the GSM-GPRS core network, the GSM-UMTS core network has two different parts: a circuit-switched MSC and a packet-switched GRPS support node (GSN). The core network access point for GSM circuit-switched connections is the GSM MSC, and for packet-switched connections it is the SGSN.

v. GSM-defined services (up to and including GSM Phase 2+) are supported in the usual GSM manner.

vi. The GSM-UMTS core network implements supplementary services according to GSM principles (HLR-MSC/VLR). New services, beyond Phase 2+ are created using new service capabilities.

vii. In addition to new services provided by the GSM-UMTS network itself, many new services and applications will be realized using a client/server approach, with servers residing on service local area networks (LANs) outside the GSM-UMTS core network. The core network will ultimately be used for the transfer of data between the end-points, the client and the server.

viii. Intelligent Network (IN) techniques are one way to provide seamless interworking across GSM-UMTS networks. Customized Applications for Mobile Enhanced Logic (CAMEL) already provides the basis for GSM/IN interworking.

ix. The combination of an Asynchronous Transmission Mode (ATM) cell-based transport network, WCDMA’s use of variable-rate speech coding with improved channel coding, and an increased volume of packet data traffic over the air interface will mean a saving of about 50% in transmission costs, compared with equivalent solutions.