Mobile and wireless have known a success that is beyond the most optimistic initial expectations. In some countries, namely European ones, the penetration of mobile communications is around 100%, which means that virtually everyone capable of using a mobile phone has (at least) one. How did we get here? What were the reasons for this huge success? These questions have been discussed over and over, and are not addressed here. Nevertheless, one thing is certain: in the past, someone, somewhere, had a vision that we all could use a single communications device under the well-known motto ‘anytime, anywhere’.

In the .rst years of 1980s, Europe was at the very beginning of the commercial exploration of mobile communications services (exclusively voice at the time), almost each country presenting its own system (the so-called 1st Generation (1G)). Things taken for granted nowadays, like roaming, were not possible, in most of cases not even between countries using the same system. The panorama was very much different from the one we live in today.

Then, as a consequence of the previously mentioned vision, a pan-European mobile communications system was developed, enabling European citizens to move around the common European space, communicating using their mobile phones. Hence, the Global System for Mobile Communications (GSM) was born (de.ning the commonly accepted concept of 2nd Generation (2G)), the rest of the success story is well known, and will not be told here.

Universal Mobile Telecommunications System (UMTS), the successor to GSM in Europe (usually designated by 3rd Generation (3G)), found itself being different from its predecessor by offering users a set of services that were not (initially) foreseen for GSM, i.e. multimedia in general (in particular, ranging from video-telephony to Internet access). At the time UMTS was being outlined, the vision was to give mobile users, already used to making calls with their mobile phones, the possibility to use services on their phone that would contribute to an increase in their means of communication. Since then the technical evolution of mobile and wireless communication systems has witnessed the appearance of a panoply of systems, encompassing Digital Video Broadcasting (DVB), High Performance Radio Local Area Network (HIPERLAN) and Bluetooth, to mention only a few within European initiatives (some of which were not actually implemented into commercial products). Outside Europe, many other systems were developed, and made a path parallel to the European ones. For the future, mobile and wireless applications and services are likely to become pervasive, with a wide spread use of devices. Computation and communication capabilities are being integrated in a large variety of devices, from simple sensors and interactive appliances (cards, rings, eyeglasses, etc.) via pocket and lap-sized devices to wall or table screen working areas. The technology will undergo a transformation, from an expensive, highly visible, ‘hi-tech’ technology as in early mobile phones, over the current situation where (almost) everyone owns a mobile phone, to a ‘disappearing technology’ that is present everywhere and taken for granted. Since the current cellular mobile approach, with its excellent mobility management and coverage properties, does not scale everywhere into large bandwidths, the result will be heterogeneous infrastructures with moderate bandwidth wide area coverage, and a local high bandwidth wireless coverage. Moreover, there is clearly the need to invent new access techniques and network architectures, so that future use of mobile and wireless communications can be made in an effective way. Such a vision challenges many of the current paradigms in mobile and wireless communications.

Currently, there is lack of a unique concept for the incoming 4th Generation (4G). A new vision should be set; as in the past, one can almost say that the probability of increased success can be measured by the way this vision creates a disruption with the existing networks and systems. On the one hand, one cannot aim at farfetched objectives, which are very unlikely to be reached within an acceptable timeframe. On the other, having as an objective something similar to the Olympic Games motto (‘Citius, Altius, Fortius’, meaning ‘Faster, Higher, Stronger’), applied to current systems and techniques (i.e. more of the same, but just better), is too shortterm.

The old vision of ‘anywhere, anytime’ could easily be replaced by, ‘any network, any device, any content’. Basically, this vision carries many implications, some of which are discussed in what follows. It cannot be expected that users make a decision on the network to be used on their common use of the system; hence, the adaptability of networks to the type of users and information they are communicating will be an essential feature. Users will be capable of communicating how, where and whenever they want to, but it also implies that the complexity of networks and systems should be concealed from them, even if they are using more than one system and/or network simultaneously to carry the information.

The use of the system will tend to be independent of the device. One can imagine that users will just carry a kind of Radio Frequency Subscriber Identity Module (RF SIM), i.e. simply a small card that carries all their information and that communicates via RF with all the devices available in its range. This will enable users to take advantage of many types of devices, using those that are more appropriate for a given service or location. The more important role of Personal Area Networks (PANs) and ad hoc networking will set new borders. Sensor networks will become increasingly important, and the number of devices people carry with them (knowingly or unknowingly) will increase. Machine-to-machine communications will de.nitely need to be taken into account, because they help in increasing system intelligence and in concealing technology from users. Users will be provided with and have access to content and information they want in a useful way, namely transmission speed. In the future, much of the user information may indeed be local, as opposed to information that does not depend on location. Moreover, peer-to-peer communications will play a key role.

Sometimes the user requests the information, i.e. ‘user access to information’, while other times it is the ‘information that accesses the user’, based on the user’s personal or family pro.le. Access to the vast range of information and content has to consider a user’s ‘techno-ability’, and must be simple and intuitive to use. The success of such vision depends very much on the simplicity of access and use of services and operation of devices.

Content clari.es that the game is no longer played only with voice, but rather it extends far beyond that, not only enabling the myriad of services and applications that everyone talks about these days, but also certainly including others that have not yet been foreseen. A future vision cannot be complete without the de.nition of the future application scenarios and users. A good starting point from which one should draw trends is to look at users as our children/grand children who will be the active population in 15–20 years’ time. Moreover, content needs to be meaningful, since, on the one hand, non-desired information (e.g. advertisement, spam, virus, etc.) and privacy are proving problematic in today’s communications, as is evident in computing (e.g. e-mail, and intrusive and destructive Internet access); on the other, it also means that .ltering of information is very important, so that users get what they really want.

But there is the need to stretch the science of mobile and wireless communications beyond radio and computer science into new areas of knowledge. Taking the main priorities that are identi.ed these days for research and development, one can identify links with them: biology (e.g. use of biometrics for user identi.cation), medicine (e.g. measurement of the health state and transmission of an alarm in case of a problem), psychology (e.g. sensing the mood and state of mind of the user), sociology (e.g. interaction with other ‘compatible’ users), nano-technologies (incorporation of circuitry/terminals in common use objects, such as spectacles), materials (e.g. cooperation with the clothing industry for the use of jackets for virtual reality), transport (e.g. placing terminals in cars), environment (e.g. decreasing ‘electromagnetic pollution’), energy (e.g. expanding the lifetime of the batteries), among others. Finally, the information should be ‘multisensory’ making use of all .ve human basic senses. Clearly, the realisation of the future vision of mobile and wireless communications demands multidisciplinary research and development, crossing the boundaries of the above sciences and different industries.

Many steps are required to make this vision a reality, and clearly from the establishment of this macroscopic vision, a number of tasks and challenges need to be identi.ed and solved at the microscopic scale. The work performed in COST Action 273 – Towards Mobile Broadband Multimedia Networks Research (COST 273) intended to give small contributions at the latter scale.