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Service Platform Reference Model: Advanced Services


Figure 1.4 Service platform reference model: advanced services


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Figure 1.5 Service platform reference model: system management

1.2.2.3 System management

As depicted in Figure 1.5, system management is the aspect related to the mechanism of supporting services. The functions of this part include: QoS, security/authentication/authorization/accounting, remote server/database, environmental adaptation, social. This system management model aims to enhance security/authentication/accounting as the core element of the services that underpin the deployment of 4G mobile society and provide the system with the ability to overcome various types of errors. The application QoS concept coordinates the network QoS used, so that continuous high-quality data transmission against congestion is provided even under adverse conditions.

1.2.3 System infrastructure reference model

1.2.3.1 Typical examples and interfaces for new radio access networks

Five typical examples of scenarios in a new radio access network and examples of interfaces for each scenario are shown in Figure 1.6. In this figure, R1- R5 show the type of radio interface, N1-N3 show the type of network interface.

Scenario 1 is an example of a new wireless access capability in an outdoor environment. On average, faster wireless packet rates can be achieved when the terminal is close to the base transceiver station (BTS). Scenario 2 is an example of a new mobile access capability or new unlicensed wireless access capability in a large indoor environment such as a large office building or a store. Scenario 3 is an example of a new unlicensed wireless access capability in a small indoor environment such as a home. Scenario 4 is an example of a moving network capability. In this example, moving network nodes (MNNs) will be installed in moving objects such as trains and buses to enable communication between base stations and mobile stations via MNNs. Scenario 5 is an example of an ad-hoc model between mobile stations, where the mobile stations are equipped with an R5 radio interface that allows radio communication between mobile stations. Note that these cases are just a few examples in a 4G mobile system, so it is quite conceivable to configure a multi-hop network by connecting base stations with radio connections.


Figure 1.6 Radio interface and real-world context of new radio access

In addition, there will be great demands to design and develop these five radio interfaces with a high degree of universality, so that 4G mobile system terminals can easily control the radio multi-band capability and can be used for various purposes in various environments.

1.2.3.2 Functional configuration for nodes/terminals in 4G mobile system

Figure 1.7 illustrates examples of functional configurations for nodes/terminals in a 4G mobile system. Considered as functional layers, services and applications (F5), service support (F4), network control and transport (F3), resource and link management (F2) and wireless access functions (F1) are defined. F5-F3 correspond to service and application domains, service platform, packet-switched core network and Figure 1.1 corresponds to where F5, F4 correspond to in the new radio access domain.


Figure 1.7 Example of functional configuration for nodes/terminals

In other words, when considered as node/terminal types, they include: Bridge, which covers functional classes F1-F2; Router, which covers functional classes F1-F3; management server, which covers functional classes F1-F4; and terminal types, which cover functional classes F1-F5.

1.3 Technologies applied in 4G mobile systems

To achieve high transmission speed and large capacity in 4G mobile system, many advanced technologies for terminal equipment, network infrastructure, service platform as well as new radio access network have been researched, tested and achieved the proposed results. The following are some technologies applied to the future 4G mobile system.

1.3.1 High-speed large-capacity transmission technology

To achieve transmission rates of approximately 100Mbps in outdoor environments and 2Gbps in indoor environments, and to make the wireless access network compatible with IP-based hierarchical network architectures, the following transmission technologies have been researched and developed:


Orthogonal frequency and code division multiplexing with variable spreading factor: VSF-OFCDM (Variable Spreading Factor – Orthogonal Frequency and Code Division Multiplexing).

Subcarrier Selecting Multi Carier Code Division Multiple Access: SCS- MC-CDMA (Subcarrier Selecting Multi Carier Code Division Multi Access).

Figure 1.8 Basics of SCS-MC-CDMA

Orthogonal Frequency Division Multiple Access: OFDMA (Orthogonal Frequency Division Multiple Access).

Interleaved Frequency Division Multiple Access: IFDMA (Interleaved Frequency Division Multiple Access).

1.3.2 Technological features of 4G

1.3.2.1IP Traffic Support

The advent of VoIP has shown that voice transmission can be easily implemented over packet-switched IP networks, although there are still challenges with end-to-end delay due to deployment over existing network infrastructure. The 4G network architecture is built with the primary goal of providing high quality IP services, the ability to handle voice traffic and real-time traffic will be a secondary goal. Providing on-demand quality services over wireless networks is a major challenge for 4G systems.

1.3.2.2 Good mobility support

In 4G systems, users will be mobile over a significant area and will communicate via radio terminals. Users must be able to communicate using a unique identification number. Thus, there must be a way to map from the number

This identifier is then converted into an address to which packets are routed. This mapping must be user controlled, as only the user can change the destination address to regulate the caller's access. In cases where the source-to-destination path crosses multiple network segments, it is not practical for this mapping to be related to a single network operator. 4G networks will have to have a suitable means of identifying users and allowing the user to control the identifier and perform efficient mapping to a common destination.

1.3.2.3Supports various wireless technologies

1G, 2G and 3G mobile systems used spectrum reserved for terrestrial mobile networks and licensed by a small number of network operators in each country. The inconsistency in when and how spectrum was allocated led to the need for multi-mode phones that could operate in a variety of frequency bands.

In 4G systems, different radio access technologies are used. The current trend is to use spectrum in the ISM unlicensed band. Bluetooth technology (recently standardized by IEEE as standard 802.15.1) is used as the technology for wireless personal area networks (WPAN). IEEE 802.11b is used for wireless local area networks (WLAN) also in this frequency band. These technologies are increasingly used to provide broadband services to users in office buildings, universities or in urban areas. There are also new versions of this standard such as 802.11a operating in the 5 GHz band and 802.11g operating in the same frequency band as 802.11b, allowing for higher transmission rates. 4G network nodes can adapt their capabilities to exploit the available spectrum efficiently.

1.3.2.4 No control link required

In the GSM network model, the user must register with the network and the network will track the subscriber as the subscriber moves from one area to another, in order to maximize the network's service capacity. The use of GSM network services is measured and charged through the home network. All activities of the mobile station also need to go through the home network. Even when the user has moved to a new area, the user still has to contact the home network to establish a connection to the billing entity before making a call.

Two GSM terminals cannot communicate directly with each other, they must first authenticate with the network, associate with the billing information, and then the network will act as an intermediary to make the connection between the two terminals. This mode makes the operator use the spectrum, allocate bandwidth to each individual, and perform measurements when each user accesses.

In the case of ISM bands, band restrictions are not necessary at all. Ad hoc networks can be established from a group of nodes, allowing nodes to communicate directly with each other, and nodes can even collaborate with each other, relaying each other's traffic.

In the absence of network management, the problem is that when a mobile node wants to communicate with a node outside its operating range, it cannot do so unless there is an intermediate node that forwards packets to that node or to the fixed network. Thus, if there is a real-time charging facility over a link, then there is no need to concern itself with the charging entity and can then forward traffic.

This approach can be used in sparsely populated areas, allowing individual mobile nodes to act as packet relays between nodes outside the operating range. In densely populated areas, this approach can also be used to encourage organizations to set up access points in areas such as university campuses or shopping centers. Organizations that do this will become 4G network operators.

1.3.2.5 End-to-end security support

Security in 2G and 3G mobile systems is focused primarily on two main services. First, the mobile user must be authenticated by the network. This authentication usually stops at linking the user to the billing entity. When accounts are prepaid, the billing entity usually does not store information about the user. In this case, there is no end-to-end exchange of authentication information between the user and the peer entity at the other end.

The second security service provided by 2G and 3G networks is information encryption. Since this service does not prevent attacks using scanning devices, it is not a substitute for end-to-end encryption.

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