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Lý thuyết mạng không dây P11

Introduction to PAN Technology and Applications 11.1.1 Historical Overview The concept of a Personal Area Network (PAN) differs from that of other types of data networks (e.g. LAN, MAN, WAN) in terms of size, performance and cost (Figure 11.1). 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. The term POS is used to define the space in the near vicinity of a person or device and can be thought of as a bubble that surrounds him. As the person goes through his regular daily. | Wireless Networks. P. Nicopolitidis M. S. Obaidat G. I. Papadimitriou and A. S. Pomportsis Copyright 2003 John Wiley Sons Ltd. ISBN 0-470-84529-5 11 Personal Area Networks PANs 11.1 Introduction to PAN Technology and Applications 11.1.1 Historical Overview The concept of a Personal Area Network PAN differs from that of other types of data networks e.g. LAN MAN WAN in terms of size performance and cost Figure 11.1 . 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. The term POS is used to define the space in the near vicinity of a person or device and can be thought of as a bubble that surrounds him. As the person goes through his regular daily activities his POS changes to include a number of different devices such as cellular phones pagers headphones PC interfaces etc. with whom the ability for easy and transparent information exchange would be useful. PANs aim to provide such ability in an efficient manner. 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. One of the first research concepts for PANs dates back to an IBM research project in 1996 and is known Data Rate kbits s 10000------------------- LAN 1000---------- PAN 100 10 MAN High performance higher cost 1 Low performance low cost 0 10 100 1000 10000 100000 Range m Figure 11.1 The various kinds of wireless networks 300 Wireless Networks as Near-field Intra-body Communication PAN NIC-PAN 1 . This approach uses the human body as the communication medium which can conduct electricity due to its natural content of salt. According to this approach NIC-PAN-compliant devices worn by a user can communicate with each other through the user s body thus no wires are needed. Furthermore a user wearing such a device can initiate communication with another device located on another user by means