Appendix D shows how to install Rococo’s Impronto Develop er Kit for Linux. Appendix E gives some hints ab out programming Java Bluetooth applications using Eclipse. Preface Abstract This thesis is concerned with the development and implementation of an ad-hoc messaging system which uses Bluetooth channels to communicate. The imple- men ted messaging system is completely written in Java and allows each device with a JSR-82 compliant Bluetoothstackto be apart of it. The messaging system is designed to support ad …

Chapter2 Bluetooth The history of Bluetoothdates back to 1994 when Ericssonlaunched an initiative to study a low-power, low-cost radio interface between mobile phones and their accessories. In 1998 they came out with theflrst Bluetoothchipand in the same year the Bluetooth Special Interest Group (SIG) was founded by Ericsson, IBM, Intel, Nokia and Toshiba. The SIG published the Bluetooth speciflcation version 1.0 in 1999[3], speciflcation 1.1 in 2001[2], and speciflcation 1.2′srelease is announced for autumn 2003[5]. The goal of Bluetoothdevelop ers was to replace cable asacommunication medium. The wireless Bluetooth technology is much more?exiblethanthe up to now used cable and infrared communication. It has been developed to allow ad-hocshortrange communication betweendifierent kinds of devices. Bluetoothusesa very low transmission pow er of about 2.5 mW, which allows operations over distances up to 10 m. The Bluetoothspeciflcation allows the transmission pow er to increase up to 100 mW, which enables the device to op- erateover distances up to 100 m[16]. Table 2.1 shows the respective maximum output power versus the distance range. Table 2.1: Bluetooth Radio Power Classes[11] Power ClassMax Output Power Range Class1 100 mW 100 meters+ Class2 2.5 mW 10 meters Class3 1mW 1meter Another aim of Bluetoothisto keep the price as low as possible. The vision that the develop ers have is to produce a Bluetoothchip which costs around $5 USDonly. Currently suchachipcosts around$20 USD[1]and Ericsson plans to produce c hips that will cost around$10 USD. Each Bluetooth device has its own unique 48 bit IEEE MACBluetooth device address (BDADDR), which identifles it unambiguously to other devices. Usually the BDADDRis divided into six parts separated byacolonwhere each part consists of two hexadecimal digits. To avoid collisionsbet weendifierent senders (interference) and for security reasons, a frequency hopping mechanism is implemented. Hence the frequency of transmission changes 1600 times per second. The base band is divided into 79 difierent channels that are used in a pseudorandom sequence by the frequency hopping algorithm. Each pair of two connected devices needs a \synchronous” clock and a common hopping sequence. The device giving the frequency hopping sequence and its clock is called the master and the other device beeing connected to is called slave. The master assigns time slices toits slaves which they can use to send data. By default the device initializing the connection establishment process is the master device. Bluetooth stacks such as BlueZ (seeSection2.5.2) also ofier the possibility to configure devices to be always master. A master can have up to seven connected slaves, such a network is called a pic onet (see Figure 2.1).

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