4G TEHNOLOGY-A SENSATION

Abstract

This paper describes architecture for differentiation of Quality of Service in heterogeneous wireless-wired networks. This architecture applies an “all-IP” paradigm, with embedded mobility of users. The architecture allows for multiple types of access networks, and enables user roaming between different operator domains. The overall 4G architecture discussed in this paper is IPv6-based, supporting seamless mobility between different access technologies. Mobility is a substantial problem in such environment, because inter-technology handovers have to be supported. In our case, we targeted Ethernet (802.3) for wired access; Wi-Fi (802.11b) for wireless LAN access; and W-CDMA - the radio interface of UMTS - for cellular access. The architecture is able to provide quality of service per-user and per-service An integrated service and resource management approach is presented based on the cooperative association between Quality of Service Brokers and Authentication, Authorization, Accounting and Charging systems. The different phases of QoS-operation are discussed. The overall QoS concepts are presented with some relevant enhancements that address specifically voice services. In particular, EF simulations results are discussed in this context.

1: INTRODUCTION

1.1: WIRELESS COMMUNICATION

1.2: GENERATIONS OF WIRELESS COMMUNICATION

2: AN ALL-IP 4G NETWORK ARCHITECTURE

3: PROVIDING QUALITY OF SERVICE

3.1: Service and Network Management in Mobile Networks

3.2 : Implicit "Session" Signaling

4: END-TO-END QOS SUPPORT

4.1: Registration and Authorization

4.2: Handover with QoS guarantees

4.3: EF PHB resource provisioning

5. TREND OF 4G TECHNOLOGIES

5.1. 4G CHARACTERISTICS

5.1.1 CONVERGENCE SERVICES

5.1.4. FLEXIBILITY AND PERSONALIZED SERVICE

5.2. CANDIDATE SERVICES BEYOND 3G

5.2.1 3GPP LTE

5.2.2. WIMAX AND WIBRO

5.2.3. IEEE 802.20

6. SCENARIOS

6.1. SCENARIO OUTLINE

6.2. SWOT ANALYSIS – 4G

7: CONCLUSION

1: INTRODUCTION

1.1 WIRELESS COMMUNICATION:

A wireless network is an infrastructure for communication “through the air”, in other words, no cables are needed to connect from one point to another. These connections can be used for speech, e-mail, surfing on the Web and transmission of audio and video. The most widespread use is mobile telephones. Wireless networks are also used for communication between computers. This note focuses on ways to set up wireless connections between computers. It gives a basic overview without becoming too technical. It will help to determine whether a wireless network might be a suitable solution. It also is a guide to more resources. Many links are to a document by Mike Jensen. The links used are examples; they are not preferred products.

1.2 GENERATIONS OF WIRELESS COMMUNICATION:

1G: These first generation mobile systems were designed to offer a single service that is speech.

2G: These second generation mobile systems were also designed primarily to offer speech with a limited capability to offer data at low rates.

3G: These third generation mobile systems are expected to offer high quality multimedia services and operative different environments. These systems are referred to as universal mobile telecommunication systems (UMTS) in Europe and international mobile telecommunication systems 2000(IMT2000) worldwide.

4G: This is user-driven, user controlled services and context aware applications. Compared to 3G ,4G has higher data rates and it has QOS which is the main criteria in 4G wireless commuication.

Availability of the network services anywhere, at anytime, can be one of the key factors that attract individuals and institutions to the new network infrastructures, stimulate the development of telecommunications, and propel economies. This bold idea has already made its way into the telecommunication community bringing new requirements for network design, and envisioning a change of the current model of providing services to customers. The emerging new communications paradigm assumes a user to be able to access services independently of her or his location, in an almost transparent way, with the terminal being able to pick the preferred access technology at current location (ad-hoc, wired, wireless LAN, or cellular), and move between technologies seamlessly i.e. without noticeable disruption. Unified, secure, multi-service, and multiple-operator network architectures are now being developed in a context commonly referenced to as networks Beyond-3G or, alternatively, 4G networks .

INTRODUCTION 4G TECHNOLOGY

In a world of fast changing technology, there is a rising requirement for people to communicate and get connected with each other and have appropriate and timely access to information regardless of the location of the each individuals or the information. The increasing demands and requirements for wireless communication systems ubiquity have led to the need for a better understanding of fundamental issues in communication theory and electromagnetic and their implications for the design of highly-capable wireless systems. In continuous development of mobile environments, the major service providers in the wireless market kept on monitoring the growths of 4th generation (4G) mobile technology. 2G and 3G are well-established as the mainstream mobile technology around the world. 3G is stumbling to obtain market share for a different reasons and 4G is achieving some confidence.

In 2010, the total mobile subscriber base in North America, Europe and Asia

Pacific, is expected to grow up to 2500 millions and penetration will be over 50%

[1]. this kind of demand growth will require the support of higher capacity networks.

Given the technology at large, 4G mobile technology as an example, will give people a more convenience and ease in lifestyle. With the “anytime, anywhere, anything,” capability, 4G wireless technology will benefit every individual regardless of time and place. Considering global standpoint, this technology stands to be the way to communicate and connect all the time with more ubiquitous means. Therefore, given the ubiquitous networking, e-commerce (or even m-commerce), unified messaging, and peer-to-peer networking, expansion to the mobile and wireless surroundings must reach its maximum possibilities. [2] The trail going to 4G mobile technology embraces lots of significant trends. Major mobile players have been investing to 2G and the succeeding technology. 4G mobile technologies are perceived to provide fast and high data rate or bandwidth, and offer packetized data communications. Since 4G is still in the cloud of the sensible standards creation, ITU and IEEE form several task forces to work on the possible completion for the 4G mobile standards as well.

Users’ experiences of latest booming Internet forces industry to investigate means to provide high data rate regardless of mobility. 4G is being discussed as

a solution to the inquiry and its vision and requirements are being standardized in various standardization bodies. 4G service vision is given from this research.

There still have large room for the purpose of service application vision: 3G is

being delayed in its commercialization and about a decade of change is left for

4G. However, we believe this paper will promote discussion of 4G services by

presenting our vision of 4G services.

In this paper, we also outline the current trend of next generation of wireless communications and investigate 4G candidate technologies. Based on this investigation, four scenarios will be discussed to predict and analyze 4G. The final section will provide some policy implications and issues.

2 AN ALL-IP 4G NETWORK ARCHITECTURE:

The overall 4G architecture discussed in this paper is IPv6-based, supporting seamless mobility between different access technologies. Mobility is a substantial problem in such environment, because inter-technology handovers have to be supported. In our case, we targeted Ethernet (802.3) for wired access; Wi-Fi (802.11b) for wireless LAN access; and W-CDMA - the radio interface of UMTS - for cellular access (Fig. 1). With this diversity, mobility cannot be simply handled by the lower layers, but needs to be implemented at the network layer. An "IPv6-based" mechanism has to be used for interworking, and no technology-internal mechanisms for handover, neither on the wireless LAN nor on other technology, can be used. So, in fact no mobility mechanisms are supported in the W-CDMA cells, but instead the same IP protocol supports the movement between cells. Similarly, the 802.11 nodes are only in BSS modes, and will not create an ESS: IPv6 mobility will handle handover between cells. 1 The concepts that are presented in this paper have been developed and tested in controlled environments in the IST project Moby Dick [2] and are currently being refined.

This Figure depicts the conceptual network architecture, illustrating some of the handover possibilities in such network with a moving user. Four administrative domains are shown in the figure with different types of access technologies. Each administrative domain is managed by an AAAC system. At least one network access control entity, the QoS Broker, is required per domain. Due to the requirements of full service control by the provider, all the handovers are explicitly handled by the management infrastructure through IP-based protocols, even when they are intratechnology, such as between two different Access Points in 802.11, or between two different Radio Network Controllers in WCDMA. All network resources are managed by the network provider, while the user only controls its local network, terminal, and applications.

In Figure 1, the key entities are:

ü A user - a person or company with a service level agreement (SLA) contracted with an operator for a specific set of services. Our architecture is concerned with user mobility, meaning that access is granted to users, not to specific terminals.

ü A MT (Mobile Terminal) - a terminal from where the user accesses services. Our network concept supports terminal portability, which means that a terminal may be shared among several users, although not at the same time.

ü AR (Access Router) - the point of attachment to the network, which takes the name of RG (Radio Gateway) - for wireless access (WCDMA or 802.11).

ü PA (Paging Agent) - entity responsible for locating the MT when it is in "idle mode" while there are packets to be delivered to it [4].

ü QoS Broker - entity responsible of managing one or more ARs/AGs, controlling user access and access rights according to the information provided by the AAAC System.

ü AAAC System - the Authentication, Authorization, Accounting and Charging System, responsible for service level management (including accounting and charging). In this paper, for simplicity, metering entities are considered an integral part of this AAAC system.

ü NMS (Network Management System) - the entity responsible for managing and guaranteeing availability of resources in the Core Network, and overall network management and control. This network is capable of supporting multiple functions:

ü inter-operator information interchange for multiple-operator scenarios;

ü confidentiality both of user traffic and of the network control information;

ü mobility of users across multiple terminals;

ü mobility of terminals across multiple technologies;

ü QoS levels guaranties to traffic flows (aggregates), using, e.g. the EF Per Hop Behaviour (PHB);

ü monitoring and measurement functions, to collect information about network and service usage;

3: PROVIDING QUALITY OF SERVICE

The design principle for QoS architecture was to have a structure which allows for a potentially scalable system that can maintain contracted levels of QoS. Eventually, especially if able to provide an equivalent to the Universal Telephone Service, it could possibly replace today's telecommunications networks. Therefore, no specific network services should be presumed nor precluded, though the architecture should be optimised for a representative set of network services. Also, no special charging models should be imposed by the AAAC system, and the overall architecture must be able to support very restrictive network resource usage. In terms of services, applications that use VoIP, video streaming, web, e-mail access and file transfer have completely different prerequisites, and the network should be able to differentiate their service. The scalability concerns favour a differentiated services (DiffServ) approach [5]. This approach is laid on theassumption to control the requests at the borders of the network, and that end-to-end QoS assurance is achieved by a concatenation of multiple managed entities. With such requirements, network resource control must be under the control of the network service provider. It has to be able to control every resource, and to grant or deny user and service access. This requirement calls for flexible and robust explicit connections admission control (CAC) mechanisms at the network edge, able to take fast decisionson user requests.

3.1 Service and Network Management in Mobile Networks

Our approach for 4G networks and to service provisioning is based on the separation of service and network management entities. In our proposal we define a service layer, which has its own interoperation mechanisms across different administrative domains (and can be mapped to the service provider concept), and a network layer, which has its own interoperation mechanism between network domains. An administrative domain may be composed of one or more technology domains. Service definitions are handled inside administrative domains and service translation is done between administrative domains [6]. Each domain has an entity responsible for handling user service aspects (the AAAC system), and at least one entity handling the network resource management aspects at the access level (the QoS Broker). The AAAC system is the central point for Authentication, Authorization and Accounting. When a mobile user enters the network, the AAAC is supposed to authenticate him. Upon successful authentication, the AAAC sends to the QoS Broker the relevant QoS policy information based on the SLA of the user, derived from his profile. From then, it is assumed that the AAAC has delegated resource-related management tied to a particular user to the QoS Broker. However, two different network types have to be considered in terms of QoS:

3.2 :Implicit "Session" Signalling

In this architecture, each network service being offered in the network is associated to a different DSCP code. This way, every packet has the information needed to the network entities to correctly forward, account, and differentiate service delivered to different packets. After registering (with the AAAC system) a user application can “signal” the intention of using a service by sending packets marked with appropriate DSCP. These packets are sent in a regular way in wired access networks, or over a shared uplink channel used for signalling in W-CDMA. This way of requesting services corresponds to implicit signalling, user-dependent, as the QoS Broker will be aware of the semantics of each DSCP code per each user (although typically there will be no variation on the meaning of DSCP codes between users). Thus QoS Broker has the relevant information for mapping user-service requests into network resources requirements and based on this information configures an access router.A novel concept of “session” is implemented: the concept of a “session” is here associated with the usage of specific network resources, and not explicitly with specific traffic micro-flows. This process is further detailed in section 4.

3.3 Network services offer

Services will be ofered a the network operator independently on the user applications, but will be flexible enough to support user applications Each offered network service will be implemented with one of the three basic DiffServ per-hop behaviours (EF, AF, or BE), with associated bandwidth characteristics. Table 1 lists the network services used in the tests. The network services include support for voice communications (e.g. via S1) and data transfer services. Delay, delay jitter and packet loss rate are among the possible parameters to include in the future, but no specific control mechanisms for these parameters are currently used. The services may also be unidirectional or bi-directional. In fact, the QoS architecture can support any type of network service, where the only limit is the level of management complexity expressed in

terms of complexity of interaction between the QoS Brokers, the AAAC systems and the AR that the network provider is willing to support.

4: END-TO-END QOS SUPPORT

Given the concepts described in section 3, the entities developed in the project can support end-to-end QoS, without explicit reservations at the setup time. Three distinct situations arise in the QoS architecture: i) registration, when a user may only use network resources after authentication and authorization, ii) service authorisation, when the user has to be authorised to use specific services; and iii) handover – when there is a need to re-allocate resources from one AR to another.

4.1 :Registration and Authorisation

The Registration process (Figure 2) is initiated after a Care of Address (CoA) is acquired by the MT via stateless auto-configuration, avoiding Duplicate Address Detection (DAD) by using unique layer-2 identifiers [7] to create the Interface Identifier part of the IPv6 address. However, getting a CoA does not entitle the user to use resources, besides registration messages and emergency calls. The MT has to start the authentication process by exchanging the authentication information with the AAAC through the AR. Upon a successful authentication, the AAAC System will push the NVUP (network view of the User Profile) to both the QoS Broker and the MT, via the AR. Messages 1 to 4 on Figure 2 detail this process. The same picture shows how each network service is authorized (messages 5 to 8). The packets sent from the MT with a specific DSCP implicit signal the request of a particular service, such as a voice call (supported by network service S1, as in Table 1). If the requested service does not match any policy already set in the AR (that is, the user has not established a voice call before, e.g.), the QoS attendant/manager at the AR interacts with the QoS Broker that analyses the request and authorises the service or not, based on the User NVUP (Network View of the User Profile) and on the availability of resources. This authorisation corresponds to a configuration of the AR (via COPS [10]) with the appropriate policy for that user and that service (e.g. allowing the packets marked as “belonging” to voice call to go through, and

configuring the proper scheduler parameters, as we will see in section 4.3). After that, packets with authorised profile will be let into the network and non-conformant packets will restart the authorization process once more, or will be discarded.

4.2: Handover with QoS guarantees

One of the difficult problems of IP mobility is assuring a constant level of QoS. User mobility is assured in our network by means of fast handover techniques in conjunction with context transfer between network elements (ARs - old and new – and QoS Brokers).

When the quality of the radio signal in the MT to the current AR (called “old AR”, AR1) drops, the terminal will start a handover procedure to a neighbouring AR (called “new AR”, AR2) with better signal and from which it has received a beacon signal with the network prefix advertisement. This handover has to be completed without user perception, when making a voice call, e.g.. For achieving this, the MT will build its new care-of-address and will start the handover negotiation through the current AR, while still maintaining its current traffic. This AR will forward the handover request to both the new AR and to the QoS Broker.

4.3: EF PHB resource provisioning

Building an all-IP architecture based on a Differentiated Services introduces a problem of how to create per-domain services for transport of traffic aggregates with a given QoS. Per-domain services support data exchange by mixing traffic of different applications, therefore different aggregates are required to support delay-sensitive traffic, delay tolerant traffic, inelastic, elastic, as well as network maintenance traffic (e.g. SNMP, DNS, COPS, AAAC etc.). As applications generate traffic of different characteristics in terms of data rates, level of burstiness, packet size distribution and because the operator needs to protect the infrastructure against congestion, it is very important that aggregate scheduling will be accompanied by:

ü per-user rate limitation performed in the ingress routers (ARs) based on user profile,

ü dimensioning and configuration of network resources to allow for a wide range of user needs and services,

resource management for edge-to-edge QoS.

The basic evaluation criteria was the queuing delay and the delay jitter of EF PDB for flow S1. The SFQ algorithm exhibits the worst performance of all schedulers, especially for medium and high traffic loads on a link. A better performance exhibits the SFQ algorithm at a very low load, but it applies to average delays only. PRI, PRIs and WFQ algorithms produce comparable results. For the Moby Dick architecture we are now considering to recommend PRIs, due to its simplicity when compared to WFQ.

The PRIs limitation has yet another advantage – rate limitation does not have influence on traffic characteristics when traffic level remains within limits, and the limits can be dynamically changed without inducing abrupt delay shift. For WFQ and SFQ algorithms dynamic change of bandwidth assigned for service class changes the service rate for this class, and can cause a transient increase of delay jitter.

5. TREND OF 4G TECHNOLOGY

5.1. 4G CHARACTERISTICS

5.1.1 CONVERGENCE SERVICES

The idea of convergence means that the creation of the atmosphere that can eventually provide seamless and high-reliable and quality broadband mobile communication service and ubiquitous service through wired and wireless convergence networks without the space problem and terrestrial limitation, by means of ubiquitous connectivity. Convergence among industries is also accelerated by formation of alliances through participation in various projects to provide convergence services.

4G mobile systems will mainly be characterized by a horizontal communication model, where such different access technologies as cellular, cordless, wireless LAN type systems, short-range wireless connectivity, and wired systems will be combined on a common platform to complement each other in the best possible way for different service requirements and radio environments [3].

The development is expected to inspire the trend of progressive information technologies a far from the current technical focus on fully mobile and widespread convergence of media. The trends from the service perspective include integration of services and convergence of service delivery mechanisms.

In accordance with these trends, mobile network architecture will become flexible and versatile, and new services will be easy to deploy.

5.1.2. BROADBAND SERVICES

Broadband is a basis for the purpose of enabling multimedia communications including video service, which requires transmission of a large amount of data; it naturally calls media convergence aspect, based on packet transport, advocating the integration of various media on different qualities. The increasing position of broadband services like Asymmetric Digital Subscriber Line (ADSL) and optical fiber access systems and office or home LANs is expected to lead to a demand for similar services in the mobile communication environment. 4G service application characteristics will give broadband service its advantages;

1) Low cost

To make broadband services available to the user to exchange various kinds of information, it is necessary to lower charges considerably in order to keep the cost at or below the cost of existing service. PTC’07 Proceedings

2) Coverage of Wide Area

One feature of mobile communications is that it’s availability and omnipresent. That advantage is important for future mobile communication as well. In particular, it is important to maintain the service area in which the terminals of the new system can be used during the transition from the existing system to a new system.

3) Wide Variety of Services Capability

Mobile communication is for various types of users. In the future, we expect to make the advanced system performance and functionality to introduce a variety of services not only the ordinary telephone service. Those services must be made easier for anyone to use.

5.1.3. INTERACTIVE BCN (ALL-IP) WITH HOME-NETWORKING,

TELEMETRIC, SENSOR-NETWORK SERVICES

Since technologies are becoming more collaborative and essential. Evolution of all network services based on All-IP network is needed for more converged services. IP-based unified network for far above the ground quality convergence services through active access is what broadband convergence network is all about. ALL-IP or Next Generation Network-IP based convergence of wired or wired backbone network, which may be the most rapidly deployed case of convergence.

All-IP technology networking and IP multimedia services are the major trends in the wired and wireless network. The idea of the broadband convergence network (BcN) fit in the provision of a common, unified, and flexible service architecture that can support multiple types of services and management applications over multiple types of transport networks. [4]

The primary purpose of putting 4G service application into more interactive driven broadband convergence network is its applicability for home-networking, telemetric, and sensor-network service. Collaborative converged network will give a more beneficial service and application, especially if it is in broadband computing to the users and its providers.

To give more emphasis on this service application, one example is home networking as its applicability binds to give more advantage to the users and the society in terms of broadband connectivity. Far more than broadband convergence network application, telemetric application will put more tangible emphasis on the 4G mobile technology application.

5.1.4. FLEXIBILITY AND PERSONALIZED SERVICE

The key concern in security designs for 4G networks is flexibility. 4G systems will support comprehensive and personalized services, providing stable system performance and quality of service. To support multimedia services, high-data rate services with good system reliability will be provided. At the same time, a low data rate transmission cost will be maintained. In order to meet the demands of these diverse users, service providers should design personal and customized services for them. Personal mobility is a concern in mobility management. Personal mobility concentrates on the movement of users instead of users’ terminals, and involves the provision of personal communications and personalized operating environments. Implementing SDR to 4G offers an advantage benefits to service providers, manufacturers and subscribers as well; such as, for service providers; [5]

1) Enhance the effectiveness of the infrastructure resources.

2) Superior space efficiency

3) Decrease operational expenditure suitable to reduced need for hardware site upgrades.

4) Decrease capital expenditure because of rise in usage of accessible network elements.

5) Improbable and faster time to market for new service and applications.

The benefit of SDR for manufacturers is through a decrease in the number of separate platforms which will be needed for the purpose of the diverse wireless technologies.

5.2. CANDIDATE SERVICES BEYOND 3G

5.2.1 3GPP LTE

As hype about multiple standards paths in the wireless technology has caused significant confusion in the market, the initiative in 3GPP LTE or the so-called Third Generation Partnership Programmer– Long Term Evolution is the name given to a project develops the Universal Mobile Telecommunications System (UMTS) mobile phone standard to cope and manage with future requirements in terms of wireless technology. Objectives include improving efficiency, lowering costs, improving services, making use of new spectrum opportunities, and better integration with other open standards. Since the project is currently in progress, it has put itself some specific goals, much of which is leaning around upgrading UMTS to a technology name fourth generation mobile communications technology, essentially a wireless broadband Internet system with voice and other services built on top. The aim of the project comprises of: [6]

· Download rates of 100Mbps, and upload rates of 50Mbps for every 20MHz of spectrum Sub-5ms latency for small IP packets

· Increased spectrum flexibility, with spectrum slices as small as 1.6MHz.

· Coexistence with legacy standards (users can transparently start a call or transfer of data in an area using an LTE standard, and, should coverage be unavailable, continue the operation without any action on their part using GSM/GPRS or W-CDMA-based UMTS)

3GPP LTE is planned as a development to existing 3GPP standards. The project was aimed as the standard technology for 2.5 GHz “3G extension band.”

Compared to UMTS, 3GPP LTE is exclusive and solely packet-switched and IP based which means that circuit switched core network does not exist.

5.2.2. WIMAX AND WIBRO

WiMAX is Worldwide Interoperability for Microwave Access and this technology is a tandard created by IEEE to form the IEEE 802.16 standard Based pm this standard, WiBro is the service name for Mobile WiMAX in Korea. WiBro uses the Mobile WiMAX System Profile. The system profile contains a comprehensive list of features that the equipment is required or allowed to support As a result, WiBro offers the same capabilities and features of Mobile WiMAX. It describes this technology as an alternative to cable and DSL and a standards-based technology enabling and allowing the delivery of last mile wireless broadband access. The aim of the project comprises of: [7]

__Peak downlink sector data rates up to 46 Mbps, assuming a DL/UL ratio of 3:1, and peak uplink sector data rates up to 14 Mbps, assuming a DL/UL ratio of 1:1, in a 10 MHz channel

__Support end-to-end IP-based QoS

__Available different channelization from 1.25 to 20 MHz to comply with varied worldwide requirements.

In a prevailing market, operators are more interested and involved in using WiMAX for low cost, low expense voice transport and delivery of services. WiMAX has a two stage evolution steps. First, the expansion of the overall fixed wireless market will not going to happen as a result of WiMAX technology, slow migration of purchasing behavior from proprietary equipment to WiMAX equipment. In adopting and implementing WiMAX equipment, service providers will be skeptical pending and until prices drop to the point where service providers cannot manage to pay to disregard WiMAX. Currently, users will see the beginning of the 2nd stage of WiMAX, which is the dawn of metro area portability. Since 802.16e or the so called Broadband Wireless Access Standards was approved already, laptops and other mobile devices can now embed with WiMAX chipsets, so the user can now have Internet access ubiquitously with in WiMAX areas. So, the WiMAX’s 2nd stage might be very disruptive and upsetting to 3G operators and could drive a round of WiMAX network overlays in urban zones.

PTC’07 Proceedings

5.2.3. IEEE 802.20

The IEEE 802.20 or so-called Mobile Broadband Wireless Access (MBWA) specification is also the first IEEE standard that explicitly addresses the needs of mobile clients in moving vehicles. The design parameters of the specification include support for vehicular mobility up to 250 Km per hour. This criterion will support use in fleet cars and trucks, as well as in the high-speed commuter trains in use throughout much of the world.

Whereas 802.16e's roaming support is generally limited to local and regional areas, 802.20 shares with 3G the ability to support global roaming. Like 802.16e, 802.20 supports QoS to give good quality for low-latency services, unlike 3G cellular data service, which is an inherently high-latency architecture [8].

Both 802.16e and 802.20 also share synchronous efficiency between uplinks and downlinks, as opposed to the asynchronous nature of 3G cellular networks, which have lower-efficiency uplinks, relative to their downlinks. Higher efficiency uplinks can be beneficial to those business users who must perform large data synchronizations or uploads to central corporate systems from their mobile systems.

The 802.20 standard plans to combine a number of the desirable features of

802.16e with those of 3G cellular data networks, while reducing the limitations of both those modalities. Thus, 802.20 solutions will address the need for a broad spectrum of functionality for mobile business and personal computing implementations.

Several scenarios are described to display the situations of the wireless communication industry as the 4G. These scenarios are based on different wireless access technologies such as WiMAX, WiBro, 3G LTE, and IEEE802.20. In the on-going 4G studies in the standardization bodies and relative industries, one of the aims is to establish an integral wireless system that would seamlessly connect the enhanced forms of existing 3G wireless systems such as WCDMA with HSDPA. In this scenario, existing carriers will maintain present customer base and services are integrated 4G. On the other hand, however, it has become possible by technological innovation that non-3G wireless services develop as competitors against 3G services such as WiMAX, or further enhanced IEEE 802 standards. In addition, individuals and organizations have started providing open and free wireless communication services by opening up, through various technologies. Figure 2 shows that these different evolution path toward 4G. For the scenarios we provided in the paper, we assumed that the advent of 4G service will be after 2012. 4G service will be determined whether it can support 4G characteristics technically, and hold the market with service differentiation from competitors. In order to forecast the form of realization of 4G systems, we construct four scenarios in the paper.

6. SCENARIOS

6.1. SCENARIO OUTLINE

A key feature of 4G is likely to be the availability of significantly higher data rates than for third-generation (3G) systems. It has been suggested that data rates up to 100 Mbps for high mobility and 1 Gbps for low mobility should be the target value. These data rates suggest higher spectral efficiencies and lower cost per bit will be key requirements for such future systems. Additional important and expected features are likely to be increased flexibility of mobile terminals and networks, multimedia services, and high-speed data connections. Future convergence systems will clearly be another feature. Based on these visions and characteristics of the 4th generation (4G) for future wireless telecommunication, new spectrum allocation issue, and technology feasibility, the advent of 4G service will bring a number of changes of competition environment, regulation and policy as well as service change into future wireless communication. Accordingly, it is very important we expect what kinds of possibility we have for The 4G service to prepare well.

6.2. SWOT ANALYSIS – 4G

Considering 4G characteristics, expected scenarios and market trends, we can find out strengths, weaknesses, opportunities and threats of 4G with better understandings. The lists and findings follow.

Strengths in 4G:

- 4G visions take into account installed base and past investments

- Strong position of telecommunications vendors expected in the marketplace.

- Faster data transmission and higher bit rate and bandwidth, allow more business applications and commercialization

- Has advantage for personalized multimedia communication tools

Weakness in 4G:

- No large user community for advanced mobile data applications yet

- Growing divergence between telecommunications vendors and operators

- Not possible to offer full internet experience due to limited speed and bandwidth

- Comparatively higher cost to use and deploy infrastructure compared fast mobile generation

Opportunities in 4G:

- Evolutionary approach may yield opportunities for the 4G

- Emphasis on heterogeneous networks capitalizes on past investments

- Strategic alliance and coalition opportunities with traditional non telecommunication industries

- Sophisticated and mature commercialization of 4G technology would encourage more applications of e-commerce and m-commerce

- Worldwide economy recover stimulates consumption and consumer confidence, therefore bring in opportunities for telecommunication sections

- It is expected and predicted that consumers will continue to replace handsets

with newer technology at a fast rate.

- Desirable higher data capacity rates, the growth opportunity for 4G is very bright and hopeful.

Threats in 4G:

- Faster rate of growth and developments in other region

- Since 3G mobile is still in the market, it squeezes the market competition in the mobile industry.

7. CONCLUSION:

We presented an architecture for supporting end-to-end QoS. This QoS architecture is able to support multi-service, multi-operator environments, handling complex multimedia services, with per user and per service differentiation, and integrating mobility and AAAC aspects. The main elements in our architecture are the MT, the AR and the QoS Brokers. We discussed the simple interoperation between these elements and depicted the overall QoS concept. With our approach, very little restrictions are imposed on the service offering. This architecture is currently being evolved for large testing in field trials across Madrid and Stuttgart. Being an architecture specially targeted to support real time communications over packet networks, the network elements configuration must be well dissected. The simulation study summarized in the paper was a valuable input to the QoS Broker implementation and policies design, providing simple heuristics to properly configure the access routers to achieve the best possible performance. The schedulers configuration on the core routers was also determined through the results of this simulation study. This architecture still has some shortcomings, though, mostly due to its diffserv orientation. Each domain has to implement its own plan for mapping between network service and a DSCP, and thus, for inter domain service provision, it is essential a service/DSCP mapping between neighbouring domains. Furthermore, an adequate middleware function is required in the MT, to optimally mark the packets generated by the applications and issue the proper service requests, which requires extensions in current protocol stacks.