UMTS - Objectives
Of many, below mentioned are few objectives of UMTS −
UMTS - Radio Interface and Radio Network Aspects
After the introduction of UMTS the amount of wide area data transmission by mobile users had picked up. But for the local wireless transmissions such as WLAN and DSL, technology has increased at a much higher rate. Hence, it was important to consider the data transmission rates equal to the category of fixed line broadband, when WIMAX has already set high targets for transmission rates. It was clear that the new 3GPP radio technology Evolved UTRA (E-UTRA, synonymous with the LTE radio interface) had to become strongly competitive in all respect and for that following target transmission rates were defined −
- Downlink: 100 Mb/s
- Uplink: 50 Mb/s
Above numbers are only valid for a reference configuration of two antennas for reception and one transmit antenna in the terminal, and within a 20 MHz spectrum allocation.
UMTS – All IP Vision
A very general principle was set forth for the Evolved 3GPP system. It should “all IP”, means that the IP connectivity is the basic service which is provided to the users. All other layer services like voice, video, messaging, etc. are built on that.
Looking at the protocol stacks for interfaces between the network nodes, it is clear that simple model of IP is not applicable to a mobile network. There are virtual layers in between, which is not applicable to a mobile network. There are virtual layer in between, in the form of “tunnels”, providing the three aspects - mobility, security, and quality of service. Resulting, IP based protocols appear both on the transport layer (between network nodes) and on higher layers.
UMTS – Requirements of the New Architecture
There is a new architecture that covers good scalability, separately for user plane and control plane. There is a need for different types of terminal mobility support that are: fixed, nomadic, and mobile terminals.
The minimum transmission and signaling overhead especially in air, in an idle mode of the dual mode UE signaling should be minimized, in the radio channel multicast capability. It is required to be reused or extended, as roaming and network sharing restrictions, compatible with traditional principles established roaming concept, quite naturally, the maximum transmission delay required is equivalent to the fixed network, specifically less than 5 milliseconds, set to control plane is less than 200 milliseconds delay target.
Looking at the evolution of the 3GPP system in full, it may not seem less complex than traditional 3GPP system, but this is due to the huge increase in functionality. Another strong desire is to arrive at a flat structure, reducing CAPEX/OPEX for operators in the 3GPP architecture carriers.
Powerful control functions should also be maintained with the new 3GPP systems, both real-time seamless operation (for example, VoIP) and non-real-time applications and services. The system should perform well for VoIP services in both the scenarios. Special attention is also paid to the seamless continuity with legacy systems (3GPP and 3GPP2), supports the visited network traffic local breakout of voice communications.
UMTS – Security and Privacy
Visitor Location Register (VLR) and SNB are used to keep track of all the mobile stations that are currently connected to the network. Each subscriber can be identified by its International Mobile Subscriber Identity (IMSI). To protect against profiling attacks, the permanent identifier is sent over the air interface as infrequently as possible. Instead, local identities Temporary Mobile Subscriber force (TMSI) is used to identify a subscriber whenever possible. Each UMTS subscriber has a dedicated home network with which it shares a secret key Ki long term.
The Home Location Register (HLR) keeps track of the current location of all the home network subscribers. Mutual authentication between a mobile station and a visited network is carried out with the support of the current GSN (SGSN) and the MSC / VLR, respectively. UMTS supports encryption of the radio interface and the integrity protection of signaling messages.
