A Seminar Report on Bluetooth Based Smart Sensor Networks Submitted as a requirement for the partial full? llment of degree of Bachelor of Engineering Of University of Rajasthan Session: 2007-2008 Submitted to: Mr. R. K. Somani HOD(CE & IT) ITM,Bhilwara(Raj. )311001 Under the guidance of: Mr. Vijay Prakash Sharma Lecturer(CE) Submitted by: Nikhil Kumar B. E. 4th Year Computer Science & Engg. Department of Computer Engineering Institute Of Technology & Management Bhilwara(Raj. )311001 1 Acknowledgement It comes out to be a great pleasure and experience to me to have Seminar for the ful? lment in the Bachelor of Engg.. Under the guidance of Mr. Vijay Prakash Sharma, Department Of Computer Engg. & Information Technology. I would like to express my gratitude to Mr. Vijay Prakash Sharma for his inspiring guidance and sincere supervision not only in the seminer but also in the real life. His cooperation and knowledge proved as a foundation of inspiration to me at all time I worked. I would also like to express my special thanks to Mr. R. K. Somani and Mr. Prateek Pandey & all faculty members for boosting me for creative thinking and helping me to be practical which I learn as during this work.
I am heartily thankful to God & my Parents. I would thank all those who directly or indirectly helped me through the succcessful completion of my work. Nikhil Kumar Computer Engg. (Final yr. ) ITM, BHILWARA. i Preface This report is designed speci? cally to aid those interested in learning about the Bluetooth Technology and Bluetooth Based Smart Sensor Networks. It covers the most prominent points of Bluetooth including how and why it works, practical uses for the technology, major advantages over similar technologies and a host of other useful information.
Use of Report The major topics in Bluetooth Network are covered in depth. The ? rst chapter introduced the basic information of Bluetooth Based Smart sensor Network. Chapter 2 presents a brief overview of Bluetooth and give the history of Bluetoot. Chapter 3 presents working of Bluetooth, it shows how Bluetooth works in sensor Network. Chapter 4 covers Blueooth Networking Function, this chapter presents that Bluetooth Network is based on IEEE 802. 11 Standard. Chapter 5 covers Bluetooth Packet Format, it presents various packet format. Chapter 6 presents Bluetooth Network Protocols.
Chapter 7 introduces Bluetooth Topology. This chapter presents the working of piconet and scatternet. Chapetr 8 presnets Bluetooth sensor Technology, this chapter covers Smart sensor Network. Chapter 9 covers the Connection Process of Bluetooth. ii Chapter 10 presentes the which type of radiations take place in bluetooth Network. Chapter 11 covers the security of Bluetooth Network. Chapter 12 presents the Bluetooth based Applications. Chapter 13 covers the Risk Pro? le. There are two types Technological and Organizational. Chapter 14 presents the conclusion. iii CERTIFICATE Institute of Technology and Management,Bhilwara
This is certify that the work contained in this seminar report entiteled ”Bluetooth Based Smart Sensor Networks” being submitted by Nikhil Kumar to Institute of Technology and Management Bhilwara, has been carried out under my suprvision,for the award of the ? nal year seminar of B. E. in Computer Science and Engineering. Mr. R. K. Somani HOD(CE & IT) ITM,Bhilwara(Raj. ) Mr. Vijay Prakash Sharma Lecturer(CE) ITM,Bhilwara(Raj. ) iv Contents 1 Introduction 1. 1 De? nition . 1. 2 Blue Tooth 1. 3 Blue Tooth 1. 4 A Piconet . 1 1 2 2 2 4 4 5 5 6 7 7 8 9 10 13 . . . . . . . . . . . . Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Bluetooth – An Overview 2. 1 What is Bluetooth ? . . . . . 2. 2 The History of Bluetooth . . . 2. 3 Bluetooth – A Brief Overview 2. 4 The Aim of ”Bluetooth” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Working of Bluetooth 3. 1 How Bluetooth Works? . . . . 3. 2 Communication Routes . . . . . 3. 2. 1 How Timeslots are Used 3. 2. 2 Frequency Hopping . . . 3. 3 The Communications channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Bluetooth Networking Function 14 4. 1 Bluetooth Network Based on IEEE 802. 11 standard . . . . . . . . . . 14 4. 2 Physical Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5 Bluetooth Packet Format 5. 1 Access Code . . . . . . . . . . . . . 5. 1. 1 Channel Access Code (CAC) . 5. 1. 2 Device Access Code (DAC) . 5. 1. 3 inquity Access Code (IAC) . . 5. 2 Packet Header . . . . . . . . . . . . . 5. 2. 1 AM-ADDR . . . . . . . . . . 16 17 17 17 17 17 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v 5. 3 5. 2. 2 TYPE . . . . . . . . . . . . 5. 2. 3 FLOW . . . . . . . . . . . . 5. 2. 4 ARQN . . . . . . . . . . . . 5. 2. 5 SEQN . . . . . . . . . . . 5. 2. 6 Header Error Control(HEC) Payload Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 18 18 18 18 18 6 Bluetooth Protocols 19 6. 1 Protocol Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 6. 2 Stack Partitioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7 Bluetooth Topology 7. 1 Piconet . . . . . . . . . . . . . . 7. 2 Scatternet . . . . . . . . . . . 7. 3 Creating a Piconet . . . . . . . 7. 4 The Connection Establishment 22 22 24 25 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Bluetooth sensor technology 27 8. 1 What is Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 8. 2 What is Smart Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . 29 9 The Connection Process 10 Radiations in Blutooth Networks 11 Security of Bluetooth Network 12 Blutooth Application 30 32 34 36 3 Risk Pro? le 38 13. 1 Technological Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 13. 2 Market and Organizational Risks . . . . . . . . . . . . . . . . . . . . 39 14 Conclusion 41 vi List of Figures 1. 1 2. 1 3. 1 3. 2 3. 3 3. 4 3. 5 3. 6 4. 1 5. 1 6. 1 6. 2 7. 1 7. 2 7. 3 8. 1 8. 2 9. 1 Piconet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wireless Data Communication . . . . . . . . . . . . . . . . . . . . . . Communication Routs in Time slots . . . . . . . . Single-slot packets . . . Multi-slot packets . . . . Frequency hopping . . .
Noisy Radio Frequency . Time slots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 8 9 10 10 11 12 Blueooth Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Packet Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 The Bluetooth protocol Stack . . . . . . . . . . . . . . . . . . . . . . 19 Bluetooth Stack Partitioning . . . . . . . . . . . . . . . . . . . . . 21 (a)Single-slave piconet),(b) multiple-slave piconet (c) scatternet . . . 22 Piconet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Bluetooth Piconets and Scatternets . . . . . . . . . . . . . . . . . . . 24 Sensor Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Smart Sensor System . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Setting up a Bluetooth connection . . . . . . . . . . . . . . . . . . . . 30 . . . . . . . . . . . . . . . . . . . . 32 10. 1 Radations in Bluetooth Network 12. Ad hoc networks at an airport scenario . . . . . . . . . . . . . . . . . 37 vii Chapter 1 Introduction Bluetooth Based Smart Sensor Networks 1. 1 De? nition The communications capability of devices and continuous transparent information routes are indispensable components of future oriented automation concepts. Communication is increasing rapidly in industrial environment even at ? eld level. In any industry the process can be realized through sensors and can be controlled through actuators. The process is monitored on the central control room by getting signals through a pair of wires from each ? ld device in Distributed Control Systems (DCS). With advent in networking concept, the cost of wiring is saved by networking the ? eld devices. But the latest trend is elimination of wires i. e. , wireless networks. Wireless sensor networks – networks of small devices equipped with sensors, microprocessor and wireless communication interfaces. In 1994, Ericsson Mobile communications, the global telecommunication company based in Sweden, initiated a study to investigate, the feasibility of a low power, low cost ratio interface, and to ? nd a way to eliminate cables between devices.
Finally, the engineers at the Ericsson named the new wireless technology as ”Blue tooth” to honour the 10th century king if Denmark, Harald Blue tooth (940 to 985 A. D). The goals of blue tooth are uni? cation and harmony as well, speci? cally enabling di? erent devices to communicate through a commonly accepted standard for wire less connectivity. 1 1. 2 Blue Tooth Blue tooth operates in the unlicensed ISM band at 2. 4 GHZ frequency band and use frequency hopping spread spectrum technique. A typical Blue tooth device has a range of about 10 meters and can be extended to 100meters.
Communication channels supports total bandwidth of 1 Mb / sec. A single connection supports a maximum asymmetric data transfer rate of 721 KBPS maximum of three channels. 1. 3 Blue Tooth – Networks In bluetooth, a Piconet is a collection of up to 8 devices that frequency hop together. Each Piconet has one master usually a device that initiated establishment of the Piconet, and up to 7 slave devices. Master’s Blue tooth address is used for de? nition of the frequency hopping sequence. Slave devices use the master’s clock to synchronize their clocks to be able to hop simultaneously. 1. 4
A Piconet When a device wants to establish a Piconet it has to perform inquiry to discover other Blue tooth devices in the range. Inquiry procedure is de? ned in such a way to ensure that two devices will after some time, visit the same frequency same time when that happens, required information is exchanged and devices can use paging procedure to establish connection. When more than 7 devices needs to communicate, there are two options. The ? rst one is to put one or more devices into the park state. Figure 1. 1: Piconet Blue tooth de? nes three low power modes sni? , hold and park.
When a device is in the park mode then it disassociates from and Piconet, but still maintains timing 2 synchronization with it. The master of the Piconet periodically broadcasts beacons (Warning) to invite the slave to rejoin the Piconet or to allow the slave to request to rejoin. The slave can rejoin the Piconet only if there are less than seven slaves already in the Piconet. If not so, the master has to ’park’ one of the active slaves ? rst. All these actions cause delay and for some applications it can be unacceptable for eg: process control applications, that requires immediate response from the command centre (central control room).
Scatternet consists of several Piconets connected by devices participating in multiple Piconet. These devices can be slaves in all Piconets or master in one Piconet and slave in other Piconets. Using scatternets higher throughput is available and multi-hop connections between devices in di? erent Piconets are possible. 3 Chapter 2 Bluetooth – An Overview 2. 1 What is Bluetooth ? Bluetooth is a method for datacommunication that uses short-range radiolinks to replace cables between computers and their connected units. Many companies have been mulling over this idea, but it was Ericsson Mobile Communication that ? ally (in 1994) started the project that was named Bluetooth. Bluetooth is a new technology and standard, launched in 1998. It is essentially, Figure 2. 1: Wireless Data Communication a small microchip which uses a short-range radio link to exchange information, enabling wireless connectivity between mobile phones, mobile PCs and other peripherals. When two Bluetooth enabled products come within 10 metres of each other, they will automatically connect and synchronize. Because the technology uses a short-range radio link, it means that line of sight is not required for it to function.
Using this new technology, it will soon be possible to send a print command from your computer to the printer in the next room, via radio link directly through the wall! 4 2. 2 The History of Bluetooth Harold Bluetooth was a Viking chief who lived during the 10th Century as the King of Norway and Denmark. Contrary to popular opinion, Bluetooth or ”Bltand” (as known in old Viking language) had nothing to do with blue teeth; it meant dark complexion. Harold physically ? t the classic Viking image. During his reign, he waged war against Germany and managed to accumulate a huge armada of Viking ships, whose crews almost overran northern Germany.
Harold Bluetooth converted many Germans to Christianity but ultimately; he was overthrown and died in exile. In 1994, Ericsson created the ? rst concept of the technology that was later to become Bluetooth. First, they carried out a study to ? nd a low power and low cost radio interface between mobile phones and other accessories. Requirements regarding price, capacity and size were set so that the new technology would have greater potential than cable solutions between mobile devices. Initially a suitable radio interface with a corresponding frequency range had to be speci? ed.
A number of criteria for the concept were de? ned regarding size, capacity and number of other features. The radio unit was to be small enough and consume such low power that it could be ? tted into portable devices. The concept also had to be able to handle both speech and data and as a result, Bluetooth was born. 2. 3 Bluetooth – A Brief Overview The Bluetooth System: 1. It Operates in the 2. 4 GHz ISM (Industrial Scienti? c Medicine) band 2. It Has a range of 10 – 100m range (0 – 20dBm) 3. It Uses a Frequency Hop (FM) spread spectrum, which divides the frequency band into a number of hop channels 5 4.
During connection, radio transceivers hop from one channel to another (1600 hops/s) 5. It Supports 8 devices in a Piconet 6. It Has in built security and uses an error detection and correction technique called ARQ 7. Utilises non line-of-sight transmission through walls, briefcases and any other mediums and is omni-directional 8. It is regulated by governments worldwide 9. It uses 1mW of power during normal transmission (-30 to +20 dBm is optional) 10. It can operate in 2 modes – Circuit switched (common for voice communications) and Packet switched (used for Internet data and higher bandwidth communication systems) 11.
It is of low cost! 2. 4 The Aim of ”Bluetooth” The aim has been set quite hight. It is to arrive at a speci? cation for a technology that optimizes the usage model of all mobile computing and communications devices, and providing: 1. Global usage 2. Voice and data handling 3. The ability to establish ad-hoc connections 4. The ability to withstand interference from other sources in open band 5. Very small size, in order to accommodate integration into variety of devices 6. Negligible power consumption in comparison to other devices for similar use 7. An open interface standard 8.
Competitivelly low cost of all units, as compared to their non-Bluetooth correspondents. 6 Chapter 3 Working of Bluetooth 3. 1 How Bluetooth Works? This communication functions on its own, without any help from the consumer. Whenever one Bluetooth-enabled device detects another Bluetooth-enabled device, the two devices automatically synch up and create an ad hoc wireless network. Bluetooth does all this by embedding a small, low-powered radio chip into an electronic device. This radio chip has the capability to transmit both data and voice communication between devices.
Bluetooth radio chips use a radio band between 2. 4 and 2. 48 gigahertz (GHz) to send signals back and forth between devices. The radio band is unlicensed; therefore, using the frequency incurs no charge. This function is important because the radio band allows Bluetooth to function as an open standard. When one Bluetooth device senses another Bluetooth device, they set up a connection between themselves. This connection is called a piconet or a personal area network (PAN) that functions as a mini-network. In a piconet, one Bluetooth device takes the role of master, while the other device takes the role of slave.
The master device controls the communications, including any necessary transfer of data between the devices. Bluetooth has the technology to allow up to eight slaves in one piconet. If an entire house is functioning with Bluetooth devices, scatternets can form. Scatternets are a combination of piconets that work together. A scatternet can form from a connection between master and master or master and slave. Since Bluetooth signals are sent via radio waves, walls and other physical barriers do not present the problem that they do with infrared signals, which must operate with a line of site.
Bluetooth radio frequency signals can travel through most solid objects; therefore, Bluetooth devices can function properly in business o? ces or from inside a contained space. 7 3. 2 Communication Routes Bluetooth uses frequency hopping in timeslots. Bluetooth has been designed to operate in noisy radio frequency environments, and uses a fast acknowledgement and a frequency-hopping scheme to make the communications link robust, communicationwise. Bluetooth radio modules avoid interference from other signals by hopping to a new frequency after transmitting or receiving a packet.
Figure 3. 1: Communication Routs in Time slots Compared with other systems operating in the same frequency band, the Bluetooth radio typically hops faster and uses shorter packets. This is because short packages and fast hopping limit the impact of microwave ovens and other sources of disturbances. Use of Forward Error Correction (FEC) limits the impact of random noise on long-distance links. One thing that can be noted from the ? gure above is that, although Bluetooth works in an ad-hoc fashion (and not server-based) all communication is done visavi the Master unit.
There is no direct communication between slave units. Nor is it intended for the Master to route messages between slave units. Rather, if slave units ? nd that they want to talk directly to each other, they would form a new piconet, with one of them acting as Master. This does not mean that they have to leave 8 the previous piconet. More likely, they will be parked in the ”old” net unless they decide to quit the ”old” net altogether. This is not a big decision for the slave units; recon? guration in Bluetooth is dynamic and very fast. 3. 2. 1 How Timeslots are Used
Transmission/reception takes place in timeslots that are only 625 mikroseconds in duration. The Master uses even-numbered slots to address each slave in turn, and each addressed slave has the opportunity to answer in the following odd-numbered timeslot. Or it can wait for it turn next time around. In addition to this, some timeslots are used for broadcasts and as logical chan- Figure 3. 2: Time slots nels for synchronization and other control signals. Thus, we get a rotating scheme, resembling the illustration above. The slot-numbering proceeds to a very high number; it takes about a day for the slot-numbering to start over again.
The clock of the Master unit decides when these slots start and end, and the slaves will thus need to be very closely synchronized to this clock. 9 Figure 3. 3: Single-slot packets Multi-Slot packets A packet is normally contained in 1 slot, as shown above, but it can cover up to 5 slots if needed. It is then imprtant that the frequencies used in the following timeslots are those that are assigned to those slots, and that they do not follow the frequency sequence that should have normally applied. This is illustrated below. Figure 3. 4: Multi-slot packets 3. 2. 2 Frequency Hopping
Frequency hopping means that the Bluetooth technology transmits and receives on 79 hop frequencies from 2402 to 2480 Mhz, hopping in a pseudo random sequence, 1600 times a second. The technology uses Gaussian frequency shift keying modulation with the maximum data rate of 721 Kbps. A complete Bluetooth protocol stack has been developed as well as imported layers such as TCP/IP. 10 Interference is avoided by using a frequency-hop (FH) spread spectrum technology. This technology is suited for low-power, low-cost radio implementations and is used in some wireless LAN products.
The main advantage with Bluetooths transmission is the high hop rate of 1600 hops per second. Bluetooth also uses a short packet length, which is another bene? t. The ISM frequency band is divided into a number of hop channels. Every hop Figure 3. 5: Frequency hopping channel is just a fraction of the total frequency band. In Bluetooth one channel is used every 625 microseconds (one slot) followed by a hop in a pseudo-random order to another channel for another 625 microseconds. In this way the hopping spreads the Bluetooth tra? c over the entire ISM band and good protection from interference is achieved.
If one of the transmissions is interrupted for whatever reason, the probability of interference on the next hop channel is very low. Multi-slot packets can be sent over up three or ? ve 625 microsecond slots but the packets are always sent on the same hop channel. Error correction algorithms are used to correct the fault caused by jammed transmissions. Advantage of Frequency-Hopping Bluetooth has been designed to operate in noisy radio frequency environments, and uses a fast acknowledgement and frequency-hopping scheme to make the link robust, communication-wise.
Bluetooth radio modules avoid interference from other signals by hopping to a new frequency after transmitting or receiving a packet. 11 Compared with other systems operating in the same frequency band, the Bluetooth radio typically hops faster and uses shorter packets. This is because short packages and fast hopping limit the impact of microwave ovens and other sources of disturbances. Use of Forward Error Correction (FEC) limits the impact of random noise on long-distance links. Considering the example at below, one realizes that hopping out-and-into a continous range of frequencies that are subject to noise gives the communications link a etter chance to remedy transmission errors when out of the disturbed frequencies, than would have been the case if the transmission had stayed for several timeslots within the noisy frequency range. This argument does not hold true if the noise is spread over the whole frequency range in a random fashion, but sources of electromagnetic noise usually give the pattern illustrated at below. Figure 3. 6: Noisy Radio Frequency Whenever a connection (a ”piconet”) is ? rst established between 2 (or more) units, the Master-unit establishes a frequency-hopping scheme, which is communicated to the other units.
This frequency selection scheme consists of two parts: 1. selecting a sequence; 2. mapping this sequence onto the hop frequencies. 12 3. 3 The Communications channels The hopping sequence is unique for each piconet, and is determined by the Bluetooth device address of the Master. The channel is divided into 625 s long timeslots. They are cyclically numbered by the clock of the piconet Master. Bluetooth uses 4 Logical Channels: • LC Channel (Link Control) It is mapped onto the packet header. Carries lowlevel link control information, like ? ow control. Is carried on every packet except in the ID packet, which has no header. LM Channel (Link Manager) It carries control information exchanged between the link managers of the master and slave(s). • UA/UI Channels (User Asynchronous/Isochronous Data) Carries L2CAP transparent asynchronous user data.. May be transmitted in one or more baseband packets. • US Channel (User Synchronous Data) Carries transparent synchronous user data. Is carried over the SCO link. 13 Chapter 4 Bluetooth Networking Function The Bluetooth technology is quite complex. This is not so surprising, considering the task it has to handle. It is mainly based on the IEEE 802. 11 standard, brie? y described at below.
Of the 2 network modes described, Bluetooth uses the ad-hoc mode. This means that each station must observe ”netiqette” and give all other units fair access to the wireless media. The diagram shows the main building blocks. With todays technology, the Figure 4. 1: Blueooth Function transmitter/receiver-part for Bluetooths requirements could be made as small as a thumbnail (!! ), and the antenna could be more or less hidden in the unit, much as it is in mobile telephones. Thus, the connectors in corresponding older units would not be replaced by something of similar dimensions; the transceiver would just ”disappear” among other circuits. . 1 Bluetooth Network Based on IEEE 802. 11 standard The IEEE 802. 11communications standard de? nes the protocol for two types of networks; Ad-hoc and client/server. 14 The Ad-hoc network is a simple network where communications are established between multiple stations in a given coverage area without the use of an access point or server. The 802. 11- standard speci? es the etiquette that each station must observe so that all units have fair access to the wireless media. It provides methods for arbitrating requests to use the media to ensure that throughput is maximized for all of the users in the base service set.
The client/server network uses an access point that controls the allocation of transmit time for all stations and allows mobile stations to roam from cell to cell. The access point is used to handle tra? c from the mobile radio to the wired or wireless backbone of the client/server network. This arrangement allows for point coordination of all the stations in the basic service area and ensures proper handling of the data tra? c. The access point routes data between the stations and other wireless stations or to and from the network server. 4. 2 Physical Links There are two types of physical links-: 1. SCO (Synchronous Connection-Oriented) 2.
ACL (Asynchronous Connection-Less) Synchronous Connection-Oriented The SCO link is point-to-point between master and slave. The master maintains the link by using reserved timeslots at regular intervals. Packet retransmissions are not allowed. Asynchronous Connection-Less ACL provides packet-switched connections between the master and all active slaves. Packet retransmissions are usually applied to assure data integrity. 15 Chapter 5 Bluetooth Packet Format The Bluetooth packets have a ? xed format. A 72-bit access code comes ? rst in the packet. The access code is based on the master’s identity and the master’s system clock.
It provides the means for synchronisation. This code is unique for the channel and is used by all packets transmitting on the same speci? c channel. A 54-bit header follows the access code. This header contains error correction, retransmission and ? ow control information. The error correction information can be used for correcting faults in the payload and in the header itself. Finally comes the payload containing anything between 0 and 2,745 bits. There are three ? elds in Packet Format 1. Access Code 2. packet Header 3. Payload Figure 5. 1: Packet Format 16 5. 1 Access Code This is used for timing synchronization o? et compensation. There are three types of Access Code. 5. 1. 1 Channel Access Code (CAC) This Access code Identi? es a piconet. 5. 1. 2 Device Access Code (DAC) This access code is used for paging and its subsequent response 5. 1. 3 inquity Access Code (IAC) This access code is used for inquiry purpose. An access code consist of a preamble a sync word and a trailer the preamble is used for DC compensation. It consists of pattern 0101 if the least signi? cant leftmost bit in the sync word is 0 and the pattern 1010 if the leastsigni? cant bit in the sync word is similarly the trailer is 0101 if the most signi? cant bit is 0. 5. Packet Header It consists of six ? elds. 5. 2. 1 AM-ADDR It contains the active mode address of one of the slaves and transmission from the master to slave contains the slaves’s address. The zero value is measured for a broadcast from master to slave in piconet. 5. 2. 2 TYPE Identi? es the type of packet four are reversed for control packets. Remaining are ueed to convey user information. 17 5. 2. 3 FLOW It provide a 1 bit ? ow control mechnism for ACL tra? c only. When a packet with ? ow 0 is received, the station is receiving the packet must temporarily halt the transmission of ACL packets on this link when a packet with ? w 1 is received,transmisstion may resume. 5. 2. 4 ARQN Provides a 1 bit acknowledgement mechanism for ACL tra? c protected by a CRC. If the reception was successful an ACK is returned. Oterwise a NAR is returned. For no return message NAK is assumed implicity. 5. 2. 5 SEQN Provides a 1 bit sequential numbering schemes. Transmitted packets are alternately labelled with 1 or 0. This is required to ? lter out retransmission at the destination; if retransmission occures due to failing, ACK the destination receives the same same packet twice. 5. 2. 6 Header Error Control(HEC)
An 8 bit detection code used to protect the packet header. 5. 3 Payload Format The baseband speci? cation de? nes a format for the payload ? eld. For voice payloads no header is de? ned,for all ACL packets and for the data portion od SCO DV packet,a header is de? ned,for data payload,the payload format consists of three ? elds. 18 Chapter 6 Bluetooth Protocols 6. 1 Protocol Stack The Bluetooth protocols contain the standard procedures for connections and data exchange between Bluetooth devices. Figure 6. 1 shows the Bluetooth protocol stack. The Radio is the interface between the on-air channel medium and the Baseband.
The Baseband layer is responsible for channel coding and decoding. It digitizes the signals received by the radio for passing up the stack and it formats the data it receives from the Link Controller for transmission over the channel. The Link Controller is responsible for establishing and maintaining the links between Bluetooth units. The Link Manager Protocol (LMP) handles piconet management and link con? guration. It also includes procedures for enforcing link security, such as encryption and authentication procedures. Figure 6. 1: The Bluetooth protocol Stack 19
The Host Controller Interface (HCI) de? nes uniform methods for accessing and controlling the lower layers of the protocol stack, namely the baseband and the link manager. Directly above it, the Logical Link Control and Adaptation Protocol (L2CAP) provides connection-oriented and connectionless data services to the other higher level protocol layers. Its protocol multiplexing capabilities allow di? erent protocols and services to use one baseband link. The remaining protocols all utilize L2CAP links (and hence are positioned on top of that protocol). The Service Discovery Protocol (SDP) de? es procedures for discovering services of other devices as well as determining the characteristics of those services. The RFCOMM protocol de? nes a transport protocol for emulating RS-232 serial ports. The Telephony Control Protocol Speci? cation (TCS) de? nes call control signaling for establishing speech and data calls between Bluetooth devices, providing them with telephony services. The Object Exchange Protocol (OBEX) is a speci? cation for object data exchange over infrared (IR) links. Examples for using OBEX include exchanging business cards and synchronizing calendar applications.
The Bluetooth technology uses the IrOBEX protocol speci? cation to allow applications to function over both shortrange RF and IR, allowing applications to choose to use either. In the same way, the Wireless Application Protocol (WAP) includes interoperability requirements for Bluetooth as a WAP user. This allows one device to use WAP over Bluetooth links providing value-added services. 6. 2 Stack Partitioning There are three ways of implementing a Bluetooth protocol stacks as illustrated in Figure 6. 2. It may use the standard two-processor architecture, the embedded architecture, or the single-processor architecture.
In the two-processor architecture (Figure a), the Bluetooth host resides on the PC while the lower level protocols are encapsulated in a Bluetooth module. This architecture is usually implemented in add-on Bluetooth modules or PC-cards for personal computers and notebook computers. 20 The second approach (Figure b) still uses two processors but most of the protocol layers are on the target processor. This architecture is usually used in resourcelimited devices, such as mobile phones and handhelds. The third architecture (Figure c) is the single-processor architecture, used in systemon-a-chip or single-chip solutions. Figure 6. : Bluetooth Stack Partitioning 21 Chapter 7 Bluetooth Topology There can be only 2 8 Bluetooth devices talking to each other. This is called a piconet. Among these devices, there can be only one master device, all the rest are slave devices. A device can belong to two piconets meantime, serving as slaves in both piconet or a master in one and slave in another. This is called a bridging device. Bridging devices connect piconets together to form a scatternet: One could say that there are 3 types of connections in Bluetooth, as shown to the right: a) Single-slave Figure 7. 1: (a)Single-slave piconet),(b) multiple-slave piconet (c) scatternet ) Multi-slave (up to 7 slaves on one master) c) Scatternet 7. 1 Piconet A network of devices connected in an ad hoc fashion using Bluetooth technology. A piconet is formed when at least two devices, such as a portable PC and a cellular 22 phone, connect. A piconet can support up to eight devices. When a piconet is formed, one device acts as the master while the others act as slaves for the duration of the piconet connection. A piconet is sometimes called a PAN. ”Piconet” is a combination of the pre? x ”pico,” meaning very small or one trillionth, and network. When a device wants to establish a Piconet it has to perform inquiry to dis-
Figure 7. 2: Piconet cover other Blue tooth devices in the range. Inquiry procedure is de? ned in such a way to ensure that two devices will after some time, visit the same frequency same time when that happens, required information is exchanged and devices can use paging procedure to establish connection. When more than 7 devices needs to communicate, there are two options. The ? rst one is to put one or more devices into the park state. Blue tooth de? nes three low power modes sni? , hold and park. When a device is in the park mode then it disassociates from and Piconet, but still maintains timing synchronization with it.
The master of the Piconet periodically broadcasts beacons (Warning) to invite the slave to rejoin the Piconet or to allow the slave to request to rejoin. The slave can rejoin the Piconet only if there are less than seven slaves already in the Piconet. If not so, the master has to ’park’ one of the active slaves ? rst. 23 7. 2 Scatternet Two or more independent and non-synchronized piconets that communicate with each other. A slave as well as a master unit in one piconet can establish this connection by becoming a slave in the other piconet. It will then relay communications between the piconets.
A set of two or more interconnected piconets form scatternets. Figure 7. 3 shows an Figure 7. 3: Bluetooth Piconets and Scatternets illustration of piconets and scatternets. A Bluetooth unit can be a slave in two or more piconets, but it can be a master in only one. Devices that participate in two or more piconets may act as gateways, forwarding tra? c from one piconet to another. Moreover, since Bluetooth units can only transmit and receive data in one piconet, its participation in several piconets is on a Time Division Multiplex (TDM) basis.
This means that although devices can participate in several piconets, they may be active in only one piconet at any one time. Hence, devices participating in multiple piconets divide their time between the piconets, spending some time slots in one 24 and some time slots in another. Piconets may be identi? ed by the master’s identity and clock. A device wishing to be active in another piconet will have to notify the master of its current piconet that it will be inactive for a predetermined length of time. The device will then have to re-synchronize its clock (by adding an o? et) with its other master. When a slave becomes inactive in a piconet, communications between masters and the other active slaves go on as normal. On the other hand, when a master becomes inactive in its piconet, the slaves will have to wait for it to be active again before communication can resume. 7. 3 Creating a Piconet A piconet can be created in one of 4 ways: 1. A page (used by Master to connect to Slave) 2. A page scan (a unit listens for its device access code) 3. A Master Slave switch is made 4. An Unpark of a unit is made (provided there are no active slaves).
In order to establish new connections the procedures inquiry and paging are used. The inquiry procedure enables a unit to discover which units are in range, and what their device addresses and clocks are. With the paging proce-dure, an actual connection can be established. Only the Bluetooth device address is required to set up a connection. Knowledge about the clock will accelerate the setup procedure. A unit that establishes a connection will carry out a page procedure and will automatically become the master of the connection. For the paging process, several paging schemes can be applied.
There is one mandatory paging scheme which has to be supported by each Bluetooth device. This mandatory scheme is used when units meet for the ? rst time, and in case the paging process directly follows the inquiry process. Two units, once connected using a mandatory paging/scanning scheme, may agree on an optional paging/scanning scheme. 7. 4 The Connection Establishment After the paging procedure, the master must poll the slave by sending POLL or NULL packets, to which the slave responds. LMP procedures that do not require 25 any interactions between the LM and the host at the paged units side can then be carried out.
When the paging device wishes to create a connection involving layers above LM, it sends LMP host connection req. When the other side receives this message, the host is informed about the incoming connection. The remote device can accept or reject the connection request by sending LMP accepted or LMP not accepted. When a device does not require any further link set-up procedures, it will send LMP setup complete. The device will still respond to requests from the other device. When the other device is also ready with link set-up, it will send LMP setup complete. After this, the ? rst packet on a logical channel di? rent from LMP can then be transmitted. 26 Chapter 8 Bluetooth sensor technology Bluetooth sensor networks are constituted from clusters of devices using sensor technologies deployed over a speci? c area, wirelessly communicating data to a central system. Sensor networks continually monitor physical properties, processes, chemical or magnetic properties, using viable and emerging communication infrastructures. With a range of software which enhances business intelligence through data extraction and mining, sensor networks will allow an entire class of systems to be designed and deployed with breakthrough results in diverse marketplaces.
Bluetooth sensor networks rely on emerging technologies such as communication Figure 8. 1: Sensor Network 27 technologies (RF communication, ad hoc networking routing), semiconductor technologies (MEMS CMOS microprocessor), embedded systems and micro sensor technologies. Wireless sensor networks possess the potential to revolutionize business in a similar way to the emergence of the internet by providing a large number of users with various forms of information. In fact, sensor networking enjoys an enormous application potential in various ? lds, including: • Environmental and healthcare: sensing ocean temperature, gathering information about a patient’s condition • Critical industrial areas: monitoring oil containers, verifying chemical gas substance concentration • Warehouse and supply chain: monitoring currents states and history of goods with critical conservation conditions • Military: surveillance and reconnaissance A wireless sensor network consists of a large number of tiny sensor nodes, each of which is equipped with a radio transceiver, a small microprocessor and a number of sensors.
These nodes are able to autonomously form a network through which sensor readings can be propagated. Since the sensor nodes have some intelligence, data can be processed as it ? ows through the network. Given the hardware limitations and physical environment in which the nodes must operate, along with application-level requirements, the algorithms and protocols must be designed to provide a robust and energy-e? cient communications mechanism. Design of physical-layer methods such as modulation, and source and channel coding also fall in this category.
Channel access methods must be devised, and routing issues and mobility management solved. 8. 1 What is Sensor A sensor is a device that converts physical, biological or chemical input into an electrical or optical signal. To be useful, the signal must be measured and transformed into digital format which can be processed and analyzed e? ciently by computers. The information can be used by either a person or an intelligent device monitoring the activity to make decisions that maintain or change a course of action. 28 8. 2 What is Smart Sensor
A smart sensor is simply one that acquires physical, biological or chemical input, converts the measured value into a digital format in the units of the measured attribute and transmits that measured information via the Ethernet to a computer monitoring point. Figure 8. 2: Smart Sensor System A smart sensor does many things a sensor system was required to do to process a measurement and provide intelligent information. In addition, the smart sensor takes care of transmitting the processed information ready to use via the Ethernet to the system monitoring point. 9 Chapter 9 The Connection Process To demonstrate how Bluetooth devices discover and connect with one another, let us use the scenario of a laptop connecting wirelessly to a mobile phone to use dialup networking (DUN). This process is shown in Figure 9. 1. Before any device can connect to another device, it has to initially look for devices that it might connect to. In Bluetooth, this is called the Inquiry Process. The inquiring device, which we call A, sends out an inquiry packet or repeated inquiry packets and waits to receive responses back.
Discoverable devices in range respond to an inquiry by sending a Frequency Hop Synchronization (FHS) packet, which contains all the information device A needs to connect to the responding device, including the Bluetooth device’s address, page scan modes, and clock o? set. All devices that respond to the inquiry are reported to the host controller of device A. Whether or not the list of all devices discovered is presented to the user is application-dependent. At this point, device A knows which devices are in range, but it does not yet Figure 9. 1: Setting up a Bluetooth connection 30 now which devices support dial-up networking. Using the information retrieved from the inquiry process, device A now attempts to connect to the di? erent devices that responded to its inquiry in order to ? nd out what services they support. Depending on the application, device A may either 1) establish links to all the devices that responded to its inquiry and get the information about their services and later on reconnect with the one that supports dial-up networking; or 2) upon seeing that a device supports dial-up networking, directly proceed to setting up a connection with that device without ? ding out the services from the rest of the devices in the list. In Figure 10. 1, the second option is adopted. In order to ? nd out the services of a device, device A sends out paging packets. A connectable device will respond and a baseband link can be established between the two devices. Following that, a L2CAP connection will be established before they can exchange service information. This information exchange is handled by the Service Discovery Protocol. Say a device B has responded that it has the dialup networking service. A RFCOMM connection can then be established across the already existing L2CAP link.
When this has been set, a dial-up networking connection can then be established on top of the RFCOMM connection, after which the laptop can then start using the cell phone to access the phone network without any cables being needed for connections. 31 Chapter 10 Radiations in Blutooth Networks It is a matter of concern for some people that the carrier waves used by Bluetooths transmitters use the same frequency range as microwave owens (Bluetooth uses 2. 402 GHz to 2. 480 GHz). Actually, the transmitting power is far too weak to be noticeable for humans.
Moreover, the radiation is not concentrated in a beam, but dispersed more or less in all directions. When using a wireless phone or a Bluetooth device, some of the emitted RF energy is absorbed by the body. The penetration depth is about 1. 5 cm at 2450 MHz (about 2. 5 cm at 900 MHz), which means that the absorption is very super? cial. The main absorption mechanism is ? eldinduced rotation of polar molecules (for example H2O), which generates heat through molecular ”friction”. Figure 10. 1: Radations in Bluetooth Network Heating by means of radio frequencies is possible over a broad frequency range.
This is taken advantage of in microwave ovens at 2450 MHz using very high power levels (up to 1,000,000 times the power used by Bluetooth devices). However, 2450 MHz is not a resonance frequency of water. But does exposure to Bluetooth RF emission heat the human body? No it does not. The output power of a Bluetooth- 32 enabled device is far too low to cause any detectable temperature increase. Again, in comparison, the maximum increase from handheld cellular phones is less than 0. 1C. There is, however, another side to this; some people are demonstrably over-sensitive to electromagnetic radiations.
Long exposure to strong ? elds make some individuals so sensitive, after a few years, that they can no longer be near such ? elds without considerable discomfort. Bluetooth ? ts into a general development pattern where antennas for GSM-transmission and other sources of electromagnetic radiations become more and more prevalent in our cities. The future will show whether this is a healthy development. 33 Chapter 11 Security of Bluetooth Network The frequency hopping scheme used by the Bluetooth technology already makes listening in on Bluetooth links very di? cult.
In fact, the U. S. military considers a communication link using frequency hopping over 79 channels to be secure . Nevertheless, Bluetooth o? ers encryption and authentication using an algorithm based on the SAFER+ (Secure And Fast Encryption Routine) cipher algorithm. This algorithm  generates 128 bit cipher keys from a 128 bit plaintext input. When initializing a security procedure, a 128 bit key is generated from a Personal Identi? cation Number (PIN), the Bluetooth device address of the claimant, and a random number shared between the claimant and the veri? er.
The authentication procedure checks whether the two devices are using the same 128 bit key to verify that the same PIN number was entered on the two devices. If the authentication procedure is successful, a new 128 bit key is generated using a new random number from each unit, the Bluetooth device addresses of the two units, and the current 128 bit key. This key is used to produce the cipher stream to cipher and decipher the bitstream data. Bluetooth also introduces three security modes, which may be used by applications depending on their security requirements [6, 8].
Mode 1 is not secure. A device in mode 1 never initiates any security procedures. A device in mode 2 enforces security procedures at service-level. Only after a L2CAP channel has been established is any security procedure performed. Depending on the application, this can include authorization, authentication, and encryption. On the other hand, a device in security mode 3 enforces security procedures at link level. Hence, when a device fails the security measures performed by a connecting device, no link is established between the two.
As in security mode 2, security measures include authentication, encryption, and authorization. 34 In addition to these security measures, devices may also be ”invisible” should they wish to stay private. Bluetooth allows a device to stay in an undiscoverable mode, where a device does not respond to inquiry scans. This means that even if a device is in range, it will never be discovered by any device performing an inquiry scan. A device may also stay in a non-connectable mode where although it responds to an inquiry, no device can ever establish a link with it, except when the device itself initiates the link. 5 Chapter 12 Blutooth Application The following examples illustrate ? ve of these: 1. Three-in-one phone – use the same phone everywhere This is a wireless phone that will use the best telecommunication technology available . At the o? ce, it will use Bluetooth technology to communicate with other phones thereby acting as an intercom or a walkie-talkie. At home, it will function as a cordless phone, incurring ? xed-line charges. When the user is on the move, it can function as a mobile (cellular-like) phone. 2.
Internet bridge – surf the Internet regardless of the connection The user will be able to connect to the Internet anywhere, regardless of whether it is through a wireless connection using a Bluetooth link with a mobile phone or a wired connection such as a local area network (LAN), a public switched telephone network (PSTN) or a digital subscriber line (DSL). 3. Interactive conference – connect every participant for instant data exchange In conferences or meetings, participants will be able to instantly exchange information such as business cards or presentation slides using their Bluetoothenabled devices. . The ultimate headset – a cordless headset keeps your hands free This is a Bluetooth-enabled headset that allows users to connect wirelessly to their mobile phones or mobile PCs for a hands-free connection, giving users the ? exibility to concentrate on more important matters. 5. Automatic synchronization Personal devices such as a desktop computer, hand-held, mobile phone and notebook belonging to the same user will perform automatic synchronization of their Personal Information Management (PIM) applications. When the user enters the o? ce, the calendar application on the 36 ser’s mobile phone or handheld automatically synchronizes with the scheduler in the o? ce, alerting the user of any con? icts in his schedule or upcoming meetings. Today, scenarios such as those depicted in Figure 12. 1, illustrate a vision for ad hoc networks connected by Bluetooth links. In the ? gure, devices belonging to one user can interconnect with each other and they can also connect to local information points – in this example, to get updates on ? ight arrivals and departures. Figure 12. 1: Ad hoc networks at an airport scenario This article will look more closely at how Bluetooth works, what protocols and pro? es it uses as well as some of its security aspects. A simple connection process will be shown to demonstrate how the protocols work and interact with one another. Before concluding with a discussion, some issues and concerns regarding this technology will be presented including a comparison between IEEE 802. 11b and Bluetooth. 37 Chapter 13 Risk Pro? le A risk pro? le of Bluetooth technology best begins by examining alternatives. In developing Bluetooth into home consumer electronics, four primary considerations exist: cost, range, ability to transmit through walls, and speed. The only option cheaper than Bluetooth is IrDA, or infrared.
However, infrared does not travel through walls and is limited to three feet of range, and therefore is useless for the purpose that we seek to use Bluetooth for. HomeRF and 802. 11b technologies are very similar, and perform all of the necessary functions that we desire, but the costs are so high that few consumers are willing to pay that much to remove cables in their homes. This situation leaves Bluetooth, whose primary limitation is data speed. Although it is the slowest of the four technologies, Bluetooth? s speed of 1 Mbps is enough to perform many of the functions that we desire.
Also, analysts forecast that the Price of Bluetooth, which is currently 8? 10 per device, will drop signi? cantly in the coming years, which will make it more appropriate for widespread use in the home. 13. 1 Technological Risks The technological risks facing Bluetooth are moderate but include the following: 1. Limited Range The limited range of Bluet ooth, which is thirty feet, should not be too large of an obstacle. As long as a Bluetooth device is within 30 feet, Sony can look into ways to relay signals to other devices that may be out of reach of an individual product that seeks to communicate with another product. . Security Security is a risk because anyone that can tap into radio wave signals can interfere with Bluetooth devices. In an attempt to limit this, Bluetooth has designed its devices so that they are constantly switching the frequency they 38 are using at the rate of 1600 times per second. Security problems are minor because Bluetooth has plugged solutions to electronic eavesdropping and other potential attacks in future versions, such as Bluetooth 2. 0. Computer viruses are another potential threat to Bluetooth, as they are elsewhere in the world of computing.
The easier the device is to operate, the easier the device is to infect with a software virus. Bluetooth? s security is adequate for most applications, and the security measures continue to become more complex. Overall, the bene? ts o? ered from Bluetooth will outweigh the minimal security risks that might be associated with the technology. 3. Regional Con? icts and Interference Regional con? icts are another problem that users face with Bluetooth networks. Countries such as Japan, France, and Spain use the 2. 4 to 2. 48 (GHz) radio bands, which Bluetooth uses to communicate, for military communication. This presents a problem because signi? ant interference exists in these countries. The military is broadening its frequencies to help alleviate this problem, but it will take time for Bluetooth to function properly in these countries. Japan is one of the major markets of Bluetooth, but until the military intervenes to solve the radio frequency problem, Bluetooth might not grow as quickly as anticipated. 4. Limited Speed The limited speed of Bluetooth is also a risk. 1 Mbps is not a very fast speed; however, manufacturers hope to be able to increase the speed in the future. 5. Interference Another risk is the possibility of other radio waves interfering with Bluetooth waves.
This factor is especially a risk in countries such as Japan, France, and Spain, where the Bluetooth frequencies are not solely reserved for Bluetooth. However, this risk is not excessive because of the previously mentioned ability of Bluetooth to switch frequencies at the rate of 1600 times per second. 13. 2 Market and Organizational Risks The market and organizational risks associated with Bluetooth are not signi? cant. The primary market and organizational risk is the slow adoption of Bluetooth by consumers. This risk is associated with any technology, and we believe that further development of Bluetooth? capabilities and proper marketing can overcome it. Other market risks include the open standard of Bluetooth, which will allow any competitor to adapt the technology as long as they complete the certi? cation 39 process. We think that our Believe and Lead implementation strategy will allow us to minimize the risk of signi? cant competition. A ? nal market risk is the cost of Bluetooth devices. We believe this risk to be minimal since the costs of Bluetooth will fall signi? cantly in the coming years. The sole organizational risk that we foresee is Sony? s dependence on a chip manufacturer. Because of the company? numerous dealings with outsourcing various parts of the production process, we believe that Sony can manage this risk e? ectively. 40 Chapter 14 Conclusion Bluetooth is a fast growing technology. More and more devices are coming out with Bluetooth capabilities built into the hardware and applications utilizing the Bluetooth technology are starting to come out as well. Although Bluetooth-enabled devices still cost considerably more than devices without Bluetooth capabilities, they do seem to be ? nding their niche in the market. Parallel to market growth, Bluetooth is also undergoing continuous technical development. Even more pro? es will be de? ned as new usage models emerge. There is also on-going research into improving Bluetooth network performance, not only alongside other wireless networks, such as IEEE 802. 11, but also among other Bluetooth networks as well. Furthermore, Bluetooth v2. 0 is already under construction. Expected improvements from the current version include higher data rates and faster response times. However, in order to become a widely accepted technology, several factors need to come into play. Being primarily a cable replacement technology, the price of enabling a device to use the Bluetooth technology should not cost signi? antly more than the cable it replaces. Furthermore, using Bluetooth should not be any more complicated than using cables. In particular, the connection process should be as seamless as plug and play technologies. Minimal con? guration should be left to users and dependable service should be provided. This is certainly lacking in current Bluetooth solutions where a complicated set-up process and upnpredictable service has been known to frustrate potential users. Another important driver for this technology will be killer applications.
Many of the available Bluetooth hardware in the market today are already starting to address interoperability issues which plagued early releases. However, applications available 41 today are mostly single solutions such as wireless headsets for mobile phones and wireless keyboards, which usually work with only their targeted hardware. Users need to see integrated solutions and ones that deliver on the promise of interoperability. With applications that actually support the usage models, and single-chip solutions that actually meet the targeted 5 price (at high volumes), we might very well see Bluetooth in the mainstream.
Finally, regarding issues concerning the IEEE 802. 11 network, the trend seems to be that both technologies are falling into their own categories. Bluetooth is emerging as the PAN technology as initially envisioned while IEEE 802. 11 is settling into its WLAN category. In the near future, where users will be having a plethora of mobile devices around them, Bluetooth’s inherent capabilities for handling high network loads while maintaining low-power operation and higher throughput might turn out highly valuable. However, peaceful co-existence between the two technologies will have to be addressed. 2 References 1. Arfwedson, H. and Sneddon, R. Ericsson’s Bluetooth modules. Ericsson Review No. 4, 1999. 2. Bluetooth SIG. Basic Printing Pro? le Interoperability Speci? cation. 2001. http://www. bluetooth. com/dev/speci? cations. asp 3. Bluetooth SIG. Human Interface Device Pro? le. 2001. http://www. bluetooth. com/dev/speci? cations. asp 4. Bluetooth SIG. Personal Area Networking Pro? le. 2001. http://www. bluetooth. com/dev/speci? cations. asp 5. Bluetooth SIG. Speci? cation of the Bluetooth System, Core v1. 1. 2001. http://www. bluetooth. com/dev/speci? cations. sp. 6. Bluetooth SIG. Speci? cation of the Bluetooth System, Pro? les v1. 1. 2001. http://www. bluetooth. com/dev/speci? cations. asp 7. Bray, H. Teething Pains. The Boston Globe, November 11, 2002. 8. Johansson, P. , Kapoor, R. , Kazantzidiz, M. and Gerla, M. Personal Area Networks: Bluetooth or IEEE 802. 11? International Journal of Wireless Information Networks, Vol. 9, No. 2. 2002. 9. Mezoe. A Brief Introduction to BlueStack. http://www. mezoe. com/. 10. Seminarsonly. A Brief Introduction to bluetooth based Smart Sensor Network. http://www. seminarsonly. com 43