On Development of Networking Technologies and Pervasive Services

Wireless Personal Communications (2005) 33: 261–269 DOI: 10.1007/s11277-005-0571-4


C

Springer 2005

On Development of Networking Technologies and Pervasive Services PERTTI RAATIKAINEN VTT Information Technology, P.O. Box 1202, FIN-02044 VTT, Finland E-mail: [email protected]

Abstract. Development in networking technologies is enabling services that will change our daily life and living environment. The most obvious change in our way of communicating is the increase of mobility involving not only terminals but also users and services. The key enabler is the Internet Protocol, which makes the service convergence possible, i.e., development that allows services, even network technology specific ones, to be carried over all sorts of physical networks. This paper discusses the various networking aspect that affect the service delivery as well as the services themselves. Keywords: future networks, pervasive services, networking technologies

1. Introduction Development of today’s networks can be characterised by the word “convergence”. Convergence can be interpreted to take place on different layers, e.g., we speak about network convergence and service convergence. By network convergence we usually mean development, which focuses on interoperability between most varying networking concepts. This implies, for example, that one can establish connections through several sorts of networks, while these networks support required connection parameters, such as bit rate and delay. Service convergence usually refers to the development, which enables network technology specific services to be offered over most versatile physical networks. As an example we can take the voice service, which was previously accessible only over circuit switched networks but nowadays is available over packet switched networks as well. Both these convergence processes have a common denominator, Internet Protocol (IP), which is the basis for the ongoing change in the networking environment, i.e., gradual evolution from the circuit switched to packet switched networking. Convergence can be seen as a cornerstone in the process that takes us towards the vision that services are available always and everywhere. This comes concrete when we recall that the access network is everything else but a uniform network. End-users access services via most different access solutions, varying from the Plain Old Telephone Service (POTS) access to large bandwidth Wireless Local Area Network (WLAN) access and to very large bandwidth optical access. Additionally, new access techniques are introduced time after time. So the access network is hardly going to see any convergence. Regardless of this, services can be accessed and delivered over those networks thanks to the IP level convergence. When it comes to services, the network is just one aspect affecting the service evolution. Users access services via terminals and technology behind them is an equally important matter. Neither should we forget usability of those terminals or usability of the services. One should

262 P. Raatikainen also remember that, on the users’ point of view, the technology as such does not play any role. An ordinary user is not interested in the technology but the service itself; its content, reliable performance and secure communications. An additional requirement is mobility; mobility of users, services and terminals. When entering the era of purely packet-based networking those features are not easy to offer. The rest of this paper is organised as follows. Section 2 discusses the technology-related issues, such as networks and terminals. Section 3 discusses about the future services and expectations. Section 4 concludes the paper.

2. Technological Challenges 2.1. N E T W O R K I N G E NV I R O N M E N T Pervasive computing and ambient intelligence are often related to the future networking [1, 4]. Users are expected to carry devices that communicate all the time with the surrounding word. This may well be the future, but how long it will take till humans are ready for this. It obviously means that communications technology pushes its way to all possible places thus changing our living environment. It has been anticipated that there will be close proximity networks that connect to larger area networks thus forming a mix of networks and sometimes networks in networks. Examples of the close proximity networks are body area networks (BAN) and personal area networks (PAN). These have connections to larger area networks thus expanding, for example, the user’s PAN to a personal network (PN) [2, 4]. As the user moves, the associated personal network moves along with all its fine features. Personal networks will provide access to all desired information and to all subscribed services. One can envisage that the moving personal network connects to fixed higher capacity networks via base stations. In case there is no direct access to the high capacity network, ad hoc networking can help to form the required connection thus extending the coverage of the access network. So the future networks have to be auto-configurative at least to some extent [2, 3]. Mobility is here to stay and in fact is getting a stronger foothold. In some respect, it dictates the development of networking solutions directing major research and development effort to issues such as the air interface, spectral efficiency and control of mobility. This is natural since mobility is seen so important. However, the wire-line network needs to be developed as well. As the number of users and the bandwidth per user increases, base station density increases and the wire-line trunk network has to cope with the increased bit rates. On the other hand, high bit rates (>100 Mbit/s) necessitate the use of high frequency bands and high frequencies cannot be transported long distances and thus optical fibres are seen as the only way to offer future proof broadband access to the end-users [6]. Although optical fibres have been used in the trunk networks for years, optical access is still rare. The main reason for this is the high installation cost of the access links. To overcome the cost limitation, different technological solutions are being developed to obtain affordable optical access. The most promising ones are the various Passive Optical Network (PON) concepts that aim at sharing optical fibre resources among a number of end-users [17]. Physical fibres can be shared quite easily, but their transport capacity is not so easy to share in an efficient way.

On Development of Networking Technologies and Pervasive Services 263 So the future networking environment is going to change; broadband users will see optical access while all other communications turn into the mobile direction. Although optical signal is carried to customer premises, terminals will most probably be connected to the optical media by electronic wire-line or wireless solutions [7, 15]. 2.2. C O NV E R G E N C E Convergence is usually associated with the problem of integrating Public Switched Telephone Network (PSTN) type of services and IP-based data services to utilise a unified infrastructure. Although convergence is the key phrase in todays networking, it looks that in the access network the development is just the opposite. New access concepts are introduced time after time, e.g., BANs, PANs, car networks and home networks [1, 3, 8]. Even though the new networks are optimized for a particular purpose, they are increasingly interoperable, due to the common network protocol – IP. This means that networks are moving from the “single service – single network” paradigm towards “multi-services–multi-network” paradigm. Interoperability of the different networks is not so straightforward, especially when added mobility comes into the picture. Mobility of the terminals requires, for example, development of additional technical solutions to guarantee that terminals move smoothly from one access network to another. This applies also to networks that are based on the same technology but which are owned and managed by separate operators. When mobility of services and users is accounted, there is a lot of challenge for network developers [7, 8, 16]. Smooth handover, for example, poses numerous problems that require further development: signalling, connection control, quality of service (QoS) guarantees for established connection, etc. Provided that interoperability is required between circuit switched and packet switched networks, problems that need to be solved include, e.g., how to handle the situation when a connection should utilise always-on and accessed-as-needed interfaces. Another problem is related to network synchronisation; PSTN services usually require more accurate network synchronism than conventional data services [14]. For the time being, interoperability has been demonstrated between packet-based technologies, such as General Packet Radio Service (GPRS) and WLAN [1]. Thus there is a long way to go till we see real interoperability, at least between the most relevant communications networks. 2.3. M O R E B A N D W I D T H Multimedia services are perhaps the most important drivers for the increasing need for bandwidth. Other major factors contributing to the bandwidth need are the growing number of end-users and increasing processing power of terminals. In the wire-line networks, data traffic is nowadays highly symmetrical due to the peer-to-peer services, such as the shared downloading and storage applications like Napster. This is a likely trend also in the future, because symmetrical services, such as video conferencing and small-office/home-office services, are gaining more foothold. Since these kinds of services are foreseen to be used largely also in the wireless networks, the traffic will also be symmetrical in the mobile domain. Presently, the wire-line access rates vary from few hundreds of kbits/s to few tens of Mbits/s, while mobile access is limited to few tens of kbits/s [6, 12, 16]. Fixed wireless solutions, such as WLAN, offer a shared 100 Mbits/s access rate. Bandwidth of radio networks is not likely to explode, although it has been envisaged that mobile access will go up to some Mbits/s within a few years and that wireless machine-to-machine communication will utilise several

264 P. Raatikainen hundreds of Mbits/s connections [6]. Higher bit rates are enabled by new radio interfaces that will provide higher bandwidth efficiency. Furthermore, higher frequency bands are employed to obtain larger bandwidth for communication purposes [13]. Wire-line access rates are expected to grow significantly. Ethernet, which is a conventional Local Area Network (LAN) technique, is taking the role of an access technique offering 10 and 100 Mbits/s connectivity to end-users [17]. Enhanced Digital Subscriber Loop (DSL) and cable modem techniques extend line rates to few tens of Mbits/s within a few years [1, 2]. Introduction of fibre as the access media finally explodes the line rates to Gbits/s level [17]. In geographically difficult areas where broadband wire-line connections are not possible, broadband can be provided by satellite systems. 2.4. C O N N E C T I O N C O N T R O L In a heterogeneous networking environment, connection control gets an emphasised role, because different networks have different sorts of connection control schemes and combing them is everything else but trivial. In the conventional telecommunications networks connection establishment and release are based on ITU-T’s Signalling System 7 (SS7) scheme [7, 14] and in purely IP-based data networks no signalling is needed at all. To allow circuit switched connections to be carried through a packed switched network, circuits have to be emulated and Session Initiation Protocol (SIP) is taking the role of signalling in the IP networks [15]. It is to be seen whether there will be competing signalling schemes that introduce more comprehensive support for QoS. In the mobile networks, connections have to be controlled also during an existing call, i.e., networks have to exercise handover control and negotiate for adequate transport resources in case of handovers. The present mobile networks are not designed for session mobility or for handovers between networks that are based on different technology. For example, there is no common method for seamless handover between 3G and WLAN networks, even though the same operator is managing the networks. Standardisation bodies have recognised this Vertical Handover (VHO) issue and, for example, 3rd Generation Partnership Project (3GPP) is working on a concept that allows connections through 3G and WLAN networks by using interoperable authentication and charging mechanisms [9]. For the moment, it looks that handovers will work between different network technologies within a decade. Some operators have already demonstrated VHO functionality between 3G and WLAN, e.g., TeliaSonera Finland. As the convergence proceeds and services move to the packet switched word then we may see unified connection control. If wee look at the present mobile networking architecture (Figure 1) data and voice connections are controlled by separated systems and carried in parallel networks. In the becoming years, the networks are envisaged to develop into a unified direction and all services will be controlled and carried by using unified methods and networks (Figure 2). 2.5. M O R E N E T W O R K F U N C T I O N A L I T Y New services and new ways of utilising the communications networks necessitate additional network functionality. Examples of such additional functions are support of QoS, security, billing and service awareness [1]. Often mentioned new features are also location and presence awareness as well as voice recognition, which is slowly becoming a mature technology and will be used for controlling services in the networks. Home networks, which connect the

On Development of Networking Technologies and Pervasive Services 265

Figure 1. A simplified 2.5G/3G network architecture.

Figure 2. Future packet-oriented mobile network architecture.

various home appliances, are becoming more important and will be connected to the Internet via wireless or wire-line broadband connections. While the number of automated appliances increases, so increases their intelligence. Besides that the devices are used for every day communication between family members, for entertainment and for various other purposes, these devices are capable of communicating via the Internet with the world outside home. For example, equipment manufactures or service operators can update the home appliance software or, in case of failure, identify and locate the cause of the failure. Another direction in the increase of functionality can be seen in the vehicle networks. Car networks, for example, are connecting safety, communication and entertainment devices. It is foreseen that communication between cars and between the car and the traffic environment, such as the traffic information systems, will increase. The car entertainment system is foreseen to be able to download entertainment software, for example music files. There is obvious need

266 P. Raatikainen for enhanced car networks, especially in countries where the traffic volumes are high and a significant part of an ordinary workday is spent in traffic jams. The person-to-person communication services are also contributing to the network functionality requirement. They are expected to be enriched in features, introducing functions such as presence management, dynamic call management, advanced unified messaging and multimodal service management. The person-to-person communication will also be supplemented with the feeling of reality in addition to video and voice. Virtual meetings are examples of such service. All these features entail additional intelligence and functionality in the network [1]. When considering the vision that the future networks should provide always-on and alwaysbest-connected access with guaranteed end-to-end service with required QoS, security and mobility, it is clear that a lot of additional functionality is needed. This becomes even more obvious when adding the need to implement general authentication, charging and personalisation methods. Functionality for virus and digital rights management protection should also be embedded into the future communications infrastructure.

2.6. T E R M I N A L E Q U I P M E N T Development of terminals is steered by the mobility and multimedia requirement, i.e., more functionality, faster interfaces and additional intelligence are needed. These enhancements necessitate increase of terminals’ processing power, which on its turn increases power consumption. The added power consumption increases heat in the electronic devices and leads to the cooling problem. Moreover, the increased power consumption generates the need for better batteries. Today’s terminal equipment are network and service dependent stand-alone devices. The future terminals are anticipated to be multi-purpose devices or alternatively they are a collection of co-operating devices [1, 5]. On the other hand, one can say that we are approaching the post-PC era meaning that all sorts of devices, e.g., game consoles, TVs, smart handheld devices and even car appliances, are connected to the Internet in a similar way as today’s PCs. Communication between the terminal devices and human beings will diversify, implying that human voice and gestures will be used for controlling the devices and services. This development allows self-explanatory and easy-to-use interfaces that suit also for disabled and elderly people. The use of gestures and voice enables also inclusion of cultural differences in the service logic. The role of terminals is also going to change. Mobile terminals are envisaged to control other devices, they will enable Internet connectivity and they can be part of a personal area network. Sophisticated mobile terminals can be used to form ad hoc networks in temporary situations, e.g., in a concert or sport event, to build up an auto-configurative network and to extend the access network coverage. Mobile terminals are slowly evolving into the direction of all-purpose terminals. Increasing processing power enables complex functionality and increasing memory size allows downloads and storing of large files, such as video files. Samsung, for example, has announced that it will release a mobile phone that contains a hard-disc drive, a high-resolution camera, an LCD display, an MP3 player and an electronic dictionary [10]. This means that more data and networking activity will be embedded in the future terminals. When cell phones develop into portable data storage devices, we are faced with new challenges, e.g., the security implications alone become mind-boggling and troubling.

On Development of Networking Technologies and Pervasive Services 267 3. Service Evolution For the moment, we are entering the era when circuit switched services and services that have previously required a special network are increasingly being carried over the IP networks. As was stated in the previous sections, there will be a lot of technology that will support this development and allow advent of most varying new services. 3.1. U S A G E

OF

SERVICES

In the various roadmaps, future services are seen as personalised and context-aware, and users have access to the services anytime and anywhere by using the most appropriate means available [1–4]. Service delivery infrastructure should be such that individual services are easy to find and use. The user should be able to access a service anonymously, but there should be methods to identify the user reliably when necessary. The personal identification and authentication methods will become an essential part of a service, for example, to enable secure purchase and payment of goods or reliable use of administrative services through the networks. To avoid violation of privacy and misuse customers’ service-accounts, solutions to increase network security in various domains (e.g., home, work and vehicles) will be needed. New services will be based on open standards and interfaces that are interoperable in an all-IP network [1]. A flexible service platform will provide service management and it also allows QoS-based service offering and charging capabilities. Desirably, a future service platform should be an open one allowing third-party service providers to develop their services and implement them into interoperable networks. The future services will include self-learning capabilities and they will be adaptive [15]. These imply that services learn each user’s way of using the services and the services adapt to the needs and profiles of a user. Parameters that can be considered in the adaptation include, for example, context (such as location, activity and behaviour), profiles (such as likes, dislikes and hobbies), terminal type (such as PC, mobile terminal and digital TV) and available network resources (such as wire-line broadband access, mobile access and car network access). When it comes to the end-users, it looks that mobility and ease of use are the key factors [1, 4, 5]. Mobility is required to have more freedom of time and place, and the easy-to-use constraint reflects the need to have service applications that are convenient to use and do not require thorough understanding of the service logic. As a whole, communication between people is expected to be richer. It is also foreseen that the future mobile communication systems provide users with much more than just the higher data rates. According to the information society scenarios, the home is increasingly becoming a place of work [1, 11]. This means that high-bit-rate services, including peer-to-peer possibilities, should be available also at home. To meet these communication needs, homes must be equipped with wire-line broadband access, such as DSL, cable mode or optical access. Vehicles, such as the car, can be seen as extensions of the home when using, for example, communication, entertainment and information services. 3.2. C O N T E N T

IN

DIGITAL FORMAT

All service content is gradually turning into digital format, which allows, for instance, easier manipulation, secured transport and compact storage of the content. This development can

268 P. Raatikainen clearly be seen in services that contain images and voice information, e.g., TV, video, music and photographs. Added security of communication enables services, such as e-commerce, e-banking and various administrative services, to evolve. Virtually all new content that is delivered via information networks are digital. The amount of digital content is increasing very rapidly. Companies, organisations as well as individual persons create digital content constantly by using their PCs, digital cameras, video cameras and mobile phones equipped with cameras to produce huge amounts of digital content [12]. Since this development creates the need to classify, manage and search the content, new applications and services will appear to fulfil this need. When introducing the all-IP communications, security and protection of privacy are gaining more importance in convincing the users that the new infrastructure is reliable [15]. As the endusers consume more network-based services, it is crucial that the users rely on the deployed services. This creates the need to certify the user, service and content. Furthermore, it is necessary to have reliable and easy-to-use identification and authentication methods as well as methods for virus and spam prevention. Since the users normally have to pay for the used services, secure solutions are also required for the transfer of payment information together with the identification of the user. Digital rights management (DRM) addresses the problem of security, and content providers are agreeable to implement it in their systems. Strong DRM protection is already a necessity in mobile ring tone and JAVA-applications. However, all experts are not convinced that users really want DRM or what will be DRM’s business model [12]. Large entertainment companies, such as Time-Warner, consider DRM as an efficient and reliable way to protect content, e.g., the latest box-office movie. For ordinary user-created material DRM is seen as a nice-to-have feature.

4. Conclusions This paper discusses the future services highlighting the technology aspects necessary for the vision that “services are accessible anytime and anywhere” to come true and touches the issue of service development. On the technology point of view, the on-going network convergence and end-user terminal development, are the key enablers of the future services. The network and service convergence, based on the Internet Protocol (IP), allows all sorts of services to be carried over most varying physical networks. Advances in connection/session control and management of network resources allow enhanced mobility of users, services and terminals. Moreover, new feature-rich services require additional functionality from the networks and terminals. These include, for example, quality of service, security, billing and service awareness. Communication networks can also provide capabilities like location and presence awareness. Various identification and authentication features are also seen important to convince the users that the new IP-based infrastructure can be used for reliable communication. Decisive in the service development seems to be the users’ willingness to have enhanced mobility and easy-to-use services. Future services are personalised and context-aware and they should be accessible anytime and anywhere. It has also been anticipated that becoming services have self-learning and adaptation capabilities. Services can be adaptable, e.g., to context, user profiles, terminal types and available network capabilities. Service development platforms should be open to guarantee interoperable solutions.

On Development of Networking Technologies and Pervasive Services 269 As a whole, the development in the networking technologies will change our lifestyle. Mobile systems will be an inseparable part of our daily lives, e.g., there will be body-wearable sensors with pervasive communication capabilities providing added sense of security, especially, for elderly people. Although it is the networking technologies that make this to happen, we should not forget that it is the services that attract the ordinary people not the technology. Therefore, acceptance of new technology depends very much on the success of the services enabled by the technology. This success, on its turn, depends on the developed business models of the services. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

CELTIC, www.celtic-initiative.org, 2004. EUREKA, http://www.eureka.be, 2004. IST-ROADCON, http://www.roadcon.org/, 2003. IST-Ambient Networks project, http://www.ambient-networks.org/, 2004. Gartner Inc., http://www3.gartner.com, 2004. WWRF, Wireless World Research Forum, http://www.wireless-world-research.org/, 2004. ITU, International Telecommunication Union, http://www.itu.int, 2004. Wi-Fi,Wireless Fidelity, http://www.wi-fi.org, 2004. 3GPP, 3rd Generation Partnership Project, http://www.3gpp.org, 2004. Samsung, http://www.samsung.com, 2004. IEEE, http://www.ieee.org, 2004. OMA, Open Mobile Alliance, http://www.openmobilealliance.org/, 2004. OFDM Forum, Orthogonal Frequency Division Multiplexing Forum, http://www.ofdmforum.com, 2004. ETSI, European Telecommunications Standards Institute, http://www.etsi.org, 2004. F.J. Velez and L.M. Correia, “Mobile Broadband Services: Classification, Characterization, and Deployment Scenarios”, IEEE Communications Magazine, 40(4), 2002, 142–150. 16. J. De Vriendt, P. Lainé, C. Lerouge, and X. Xu, “Mobile Network Evolution: Revolution on the Move”, IEEE Communications Magazine, 40(4), 2002, 104–111. 17. G. Chiruvolu, A. Ge, D. Elie-Dit-Cosaque, M. Ali, and J. Rouyer, “Issues and Approaches on Extending Ethernet Beyond LANs”, IEEE Communications Magazine, 42(3), 80–86, 2004.

Pertti Raatikainen received PhD in information and communications technology from Helsinki University of Technology in 1996. He started his working career in Nokia Telecommunications as R&D engineer in early 1980s. In mid 1980s, he joint VTT where he held several positions: research scientist, senior research scientist and research group manager. In mid 1990s, he worked two years for Teleste Ltd. as product development manager. In late 1990s he returned to VTT and is currently acting as research professor. His research interests are focused on broadband network technologies and, especially, on switching and routing techniques.