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Introduces articles and research papers of the January 2003 issue of the journal "Wireless Networks."

The article discusses simulation of wireless network systems. Simulation is a general term that is used in many disciplines including performance evaluation of computer and telecommunications systems. A model is a description of a system by symbolic language or theory to be seen as a system with which the world of objects can be expressed. The article also reviews the main characteristics of the commonly used stochastic distributions used for the simulation of wireless networks. The article concludes with cases studies on the simulation of some wireless network systems.

The article focuses on wireless communications. Wireless networks, as the name suggests, utilize wireless transmission for exchange of information. The exact form of wireless transmission can vary. For example, most people are accustomed to using remote control devices that employ infrared transmission. However, the dominant form of wireless transmission is radio-based transmission. Radio technology is not new, it has a history of over a century and its basic principles remain the same with those in its early stage of development. As spectrum is a scarce resource, it needs to be licensed in order to ensure interference-free operation. Furthermore, the characteristics of signal propagation in street microcells and inside buildings are examined and a scheme used for modeling packet losses in wireless systems is presented. Analog transmissions have been typically been employed in older generations of wireless systems while the newer generations employ the more efficient digital transmission. An overview of techniques that increase the performance of wireless systems by combating the deficiencies of the wireless medium are presented. These include antenna diversity, multi-antenna transmission, coding, equalization, power control and multi-carrier modulation. An introductory overview of the basic techniques and interactions at the different network layers is made with the help of the OSI reference model.

The article presents information on wireless communications. The field of mobile wireless communications is currently one of the fastest growing segments of the telecommunications industry. Wireless devices have nowadays found extensive use and have become an indispensable tool on the everyday life of many people. both the professionally and personally. To gain insight into the momentum of the growth of the wireless industry, it is sufficient to state the tremendous growth in the number of worldwide subscribers of wireless systems. This figure has risen from only one mobile subscriber per 100 inhabitants worldwide in 1990 to 26 subscribers per 100 inhabitants in 1999 and the growth continues. This increasing number of subscribers is obviously reflected in monetary terms as well.

The article focuses on Personal Area Networks (PANs). The concept of a PAN differs from that of other types of data networks in terms of size, performance and cost. PANs are the next step down from LANs and target applications that demand short-range communications inside the Personal Operating Space (POS) of a person or device. There exist a number of different communication mediums to choose for implementing a PAN, such as electric and magnetic fields, radio and optical signal transmission. Finally, as in the case of all wireless networks human safety issues are of great concern. A PAN device will typically be very close to the user for long periods of time and therefore even small dangers could potentially have some impact on the user over time.

The article focuses on fixed wireless access systems. The goal of this chapter is to review the main techniques used for Wireless Local Loop (WLL) including the Multichannel Multipoint Distribution Service, and the Local Multipoint Distribution Service. It is expected that the global WLL market will exceed 202 million subscribers by the year 2005. Much of this growth will be in the developing countries where over half the world's population lacks Plain Old Telephone Service. WLL systems have a number of advantages over wired systems to subscriber local loop support.

The article focuses on third generation (3G) cellular systems. The goal of 3G wireless networks is to provide efficient support for both voice and high hit-rate data services. Third generation mobile and wireless networks aim to fulfill the demands of future services. 3G systems will offer global mobile multimedia communication capabilities in a seamless and efficient manner. Regardless of their location, users will be able to use a single device in order to enjoy a wide variety of applications. The term 3G is usually accompanied by some vagueness, as sometimes different people mean different things when they refer to it. 3G was originally defined to characterize any mobile standard that offered performance 3G systems will provide at least 144 kbps for full mobility applications in all cases, 384 kbps for limited mobility applications in macro and microcellular environments and 2 Mbps for low mobility applications particularly in the micro and picocellular environments.