him. Bluetooth devices in a network have the function of a master or Dynamic frequency selection (DFS). Network a slave, and all communication is between a master and channels are selected and changed automatically to one or more slaves, never directly between slaves. The maintain communication reliability in the presence basic Bluetooth network is called a piconet. It has one of interference and path disturbances. master and from one to seven slaves. A scatternet is an Transmit power control (TPC). Transmission power is interrelated network of piconets where any member of automatically regulated to reduce interference to a piconet may also belong to an adjacent piconet. Thus, other frequency band users and reduce average conceptually, a Bluetooth network is infinitely expand- power supply consumption. able. Figure 5.2-16 shows a scatternet made up of three High data security. Strong authentication and piconets. In it, a slave in one piconet is a master in an- encryption procedures. other. A device may be a master in one piconet only. The basic RF communication characteristics of Blue- All of the above features of HIPERLAN/2 are being tooth are shown in Table 5.2-5. dealt with by IEEE task groups for implementation in A block diagram of a Bluetooth transceiver is shown in 802.11. Specifically, the features of DFS and TPC are Figure 5.2-17. It's divided into three basic parts: RF, necessary for conformance of 802.11a to European baseband, and application software. A Bluetooth chip set Union regulations. will usually include the RF and baseband parts, with the Frequency channels and power levels of HIPERLAN/2 application software being contained in the system's are shown in Table 5.2-4. computer or controller. The user data stream originates and terminates in the application software. The baseband section manipulates the data and forms frames or data Table 5.2-4 HIPERLAN/2 frequency channels and power levels bursts for transmission. It also controls the frequency (ETSI TS 101 475 V1.3.1 (2001-12)). synthesizer acco