A Novel Concept for Fourth Generation Mobile Multimedia Communication

In this paper a view of the world-wide developments in the field of wireless broadband multimedia communications is given first. Taking this into account, a multi-disciplinary approach is presented as a combination of: promising applications, novel user-interfaces, compression, protocols geared to the mobile user and transmission techniques that give abundant bandwidth to the user. The insights of each of the research topics that contribute on the path towards the Fourth Generation Mobile Multimedia Communication is presented. Cellular Evolution: First and Second Generation. First Generation Cellular Systems were implemented in early eighties using direct analog voice modulation based on a cellular architecture. The Second Generation Cellular Systems were designed when the technical evolution of microelectronics enabled the use of full digital communication over the radio channel with portable devices. From Europe the standard GSM (Global System for Mobile communications) has emerged as an European standard and it has become the main mobile system all around the world. GSM provides services to 70 million users in Europe [1], and over 100 million users word wide not only in Europe but in 110 countries with over 200 networks all over the word. The initial transmission rate of GSM systems is 9.6 kilobits per second (kbps) with a possible increase to 14.4 kbps by changing the error protection coding. First change is High Speed Circuit Switched Data (HSCSD). This technique allows the combination of multiple time slots. By using up to four time slots, channels can be multiplexed together to offer a raw data rate of up to 64kbps. The usage of data services, especially Internet Protocol (IP) based traffic has increased rapidly in fixed networks since 1993. This has also boosted the usage of the IP data in the cellular networks, and specifically stimulated the development of General Packet Radio Service (GPRS) standard in GSM. With General packet radio service, also known as GSM2+, channel rate will go up to 164 kbps [2]. System providing general packet radio service will use packet switched resource allocation; this means that resources are allocated only when data are to be sent or received. The channel allocation is flexible: one up to eight Time Slots, (TS), (each time slot carries 21.4 kbps), and time slots are alternatively used by circuit and packet switching. Although this may appear to be a perfect evolution from GSM, it is not. It is not possible to "commute" between high speed circuit switched data and general packet radio service, because each of them requiring a priori a dedicated specialised radio. An improvement upon the former system is Enhanced Data rate for GSM Evolution, (EDGE), also know as Evolved GSM [3], [4]. By means of enhanced data GSM evolution, GSM networks will be able to handle wireless multimedia services such as Internet/intranet, videoconferencing, and electronic mail at data rates of 384 kbps. The EDGE technology is designed to be introduced in existing digital networks such as GSM and the North American Digital Advanced Mobile Phone Service (DAMPS). Increase of the rate can be achieved through higher level modulation such as 16Quadrature Amplitude Modulation (16-QAM), [5]. Figure 1: Cellular Systems Evolution Mobile Systems Convergence: Third Generation. Nowadays European mobile communication systems can be defined in 5 groups: cordless, cellular, satellite, paging and private mobile radio systems. These mobile communication systems will all be included at a common system: the Universal Mobile Telecommunications System, (UMTS). The 1st and 2nd generation cellular systems were all deployed around1 GHz spectrum domain with some extensions to higher frequencies as the earlier allocations become congested. Radio regulation authorities did allocate new spectrum for mobile use in the 2 GHz area. Initial transmission will be at 2GHz with a rate of 2Mbps in low mobility conditions, independently of the environment. This rate will be only between 144 and 384 kbps for wide area services. 144 kbps Is the minimum achievable user bit rate in any mobility condition and the UMTS system will have to support user speed up to 500 km/h [6]. There will be available up to 10 Mbps for local area mobility services by 2.005, but only in a provisional way. The final extension, everywhere, will be available by 2.010. Towards a Fourth Generation: Mobile Multimedia Communication.