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Bluetooth Paper Presentation

  1. 1. Bluetooth Technology co om m gi. .c oogi A New Era of Connectivity ntyy eent t t dd ssuu w. . w ww ww
  2. 2. Bluetooth Technology om i.c ABSTRACT ogtransfer technologies such as IrDA and Home RF. It illustrates how a nty The seemingly endless entanglement of data wires connecting de today’s electronic devices has become slightly less jumbled with the stu introduction of Bluetooth technology connection is made in Bluetooth and the creation of a wireless data link. between two environments. It mainly This article delves into the w. emphasizes the architecture of implementation and architecture of Bluetooth. It gives over all Bluetooth Bluetooth. It also describes the ww packet structure and different functional overview and applications of communication and data information Bluetooth. It gives significant protocols such as WAP, UDP, IP,TCP advantages of Bluetooth over other data
  3. 3. Bluetooth Technology ,RFCOMM, L2CAP etc. It also operating electronic devices. These explains Link Security by Data details in the article establish the om Encryption. Finally it narrates how growing need for Bluetooth technology. Bluetooth will bring a new level of i.c connectivity and convenience when og nty INTRODUCTION Blaatand"Bluetooth"2nd,king of Bluetooth is a method for data Denmark. communication that uses short-range radio WHY BLUETOOTH? de links to replace cables between computers and their connected units. Bluetooth attempts to provide significant Bluetooth is a radio frequency advantages over other data transfer stu technology utilizing the unlicensed technologies such as IrDA and HomeRF. 2.5GHz industrial, scientific and medical IrDA is already popular in PC to (ISM) band. Bluetooth is an open standard peripherals,but is severely limited by the for wireless connectivity with supporters w. short connection distance of 1m and the mostly from the PC and cell phone line of sight requirement for industries. Not surprisingly, its primary communication. Due to its RF nature market is for data and voice transfer ww bluetooth is not subjected to such between communication devices and PCs. limitations. In addition to wireless Bluetooth was invented by L.M.Ericson device connections up to 10-100m, of Sweden in 1994. The standard is devices need not be within line of sight. named after Harald
  4. 4. Bluetooth Technology Also it is designed to be low cost i.e packet) to search and locate these devices. under $10/unit. • The existing Bluetooth devices already om within the area (and usually unware of Establishing a connection in any inquiring devices) will occasionally enter an inquiry scan state of their own Bluetooth: to troll for any inquiring devices. • When a device in the inquiry scan state Linking one Bluetoooth device to another to receives an inquiry packet, it will i.c another involves a series of inquiry and respond with a frequency hop paging procedures. The inquiry process synchronization (FHS) packet that is entails the following steps: sent back to the inquiring device. • The Bluetooth device sends out an og inquiry access code packet (inquiry Once the inquiry routine is completed, the • While the paging device (the master) is paging process follows: nty paging, the target (slave) device may be • The inquiring Bluetooth device now involved in other piconets. wants to establish a connection with Occasionally, it will enter the page scan another Bluetoooth device. state and listen for pages directed to it, de • To successfully locate and page a target scanning through 16 different Bluetooth device, the paging device frequencies. When it receives a page estimates the hop frequency and clock from the paging device, it will respond stu of the target Bluetooth device using the to the page by sending an update of its FHS packet received during inquiry. clock to the paging device. • The paging device “pages” the target • Once the paging device receives a page device with the target device’s device response from the target device, w. access code (DAC). The paging device information vital for a connection is transmits the DAC on several different exchanged between the two devices. hop frequencies that it thinks the target Information exchanged includes the ww device is receiving (as calculated using device address and clock of the paging the FHS packet) and continues to do so device, which is used to determine the until a connection is made. timing and frequency-hop sequence of the newly formed piconet. When all
  5. 5. Bluetooth Technology connection information has been broken down into smaller packets and sent communicated, the connection is serially with the least significant bit sent om complete, and the two devices can begin first. Each data packet (represented in Figure to exchange data with one another. 2) contains three fields: an access code, a header, and a payload. i.c Bluetooth packet format: og Since Bluetooth is meant to be compatible with many different applications, it must be able to send data with different protocols nty quickly and efficiently. When data is transmitted at the lowest level, it is first Access codes At the beginning of each Bluetooth packet is The packet header, which follows the access an access code. The access code is used code and contains link control information, de primarily for piconet identification and co9ntain six fields: AM_ADDR, TYPE, synchronization. The access code identifies FLOW, ARON, SEQN, and HEC (Figure 4). the piconet to which each data packet • AM_ADDR, a 3-b active member stu belong; all data packets having both a packet address, is used to indicate where the header and payload present will have a 72-b packet is destined. When a slave access code; otherwise, the access code is receives a data packet, it checks the w. 68-b long. Access codes are also used packet header’s AM_ADDR. If it extensively in Bluetooth with no header or matches its own assigned AM_ADDR, payload present. The access code itself the packet will be decoded; otherwise, it ww (Figure 3) is divided into three sections- is discarded. preamble, sync word, and trailer-which are • The 4-b TYPE field indicates the type of not present in inquiry or device access packet that has been sent. There are up codes. to 16 different types of Bluetooth Packet header packets.
  6. 6. Bluetooth Technology • The FLOW bit is used for flow control. one-third the forward error correction For example, if the receive (RX) buffer (FEC) rate, extends the total bit length om of a recipient device is full, it will to 54 b. indicate in its response to the master that • The payload , which follows the header, it cannot accept any data at that can range from 0 to 2,745 b, and moment. Once it can receive more data, contains the actual data of interest. With i.c the FLOW bit is changed from 0 to 1. a packet capable of being sent during • ARQN is the acknowledge bit that every 625 micro second time slot, a informs the source whether the previous maximum bit rate of 723.2 kb/s can be og transaction was successful. achieved for an ACL, and 64 kb/s can be • The sequence (SEQN) bit allows the achieved for an ACL, and 64 kb/s for an source and the recipient to keep track of SCO. nty the packets that have been sent. The bit Bluetooth can handle the transmission of is inverted on each packet transmission many different applications. This entails and used to prevent the reception of dealing with different architectural layers to packets that may have been sent twice. decompose the application data into a form de Repeat transmission of a packet occurs suitable for transmission over a Bluetooth when the acknowledgement signal of a link, as well as to reassemble the data into successful data transaction to the master its original form at the receiving end. stu fails to transmit. The receiving device can simply compare the SEQN bit of the GENERAL BLUETOOTH packet that was previously processed to ARCHITECHTURE determine whether to discard or accept Facilitating this data transmission is a series w. the packet. of protocols within the Bluetooth system • The header error check, HEC, is used to that processes the data for suitable check the integrity and accuracy of the transmission and receipt. ww header during each packet transaction. If The general structure of a Bluetooth the HEC is incorrect, the packet is system consists of a microprocessor that discard. While the header comprises 18 handles all the baseband specifications, and b, the fact that it is encoded at a rate of several software layers that structure the
  7. 7. Bluetooth Technology data so that it may be sent properly over a into Bluetooth data packets and Bluetooth link. Figure 5 provides a good subsequently sent over a Bluetooth link. om representation of the architecture. Below RFCOMM lies the logical link At the highest architecture level lies the control and adaptation protocol (L2CAP) different communication and data that further supports the adaptation of other information protocols that can communicate communication protocols, such as telephony i.c over the Bluetooth link, including wireless control specification binary (TCS-binary) application protocol (WAP), user datagram and the Bluetooth-established service protocol (UDP), transport control protocol discovery protocol (SDP), as well as og (TCP), internet protocol (IP), and point-to- performing the multiplexing between all point protocol (PPP). While all of these are incoming upper-level protocols (RFCOMM, standalone communication protocols, they TCS, SDP), as well as performing the nty can be adapted for transmission over a multiplexing between all incoming upper- Bluetooth link. To support these different level protocols (RFCOMM, TCS, SDP). In types of communication protocols, the addition to protocol multiplexing, L2CAP is Bluetooth system architecture must be responsible for the segmentation of outgoing de capable of capable of differentiating and data packets so they may be transferred to converting data associated with these the baseband processor cannot handle data protocols into data packets that the packets of great size. L2CAP is also Bluetooth baseband controller and RF responsible for the reassembly of received stu transceiver can send. data packets, which are subsequently sent to One of the protocols within the Bluetooth one of the higher-level protocols designated architecture that is responsible for this to receive this data. w. adaptation is RFCOMM, which emulates a Once the original data has been serial port and can be used by applications segmented by L2CAP into subsequent that use the serial ports on a Bluetooth L2CAP packets, the packets are then sent to ww device. RFCOMM can take the data from the host controller interface (HCI), which is some of the higher level protocols responsible for sending data to and receiving mentioned previously and adapt it so it can data from the lower level Bluetooth be sent down to the baseband and converted hardware (baseband controller) through a physical bus (USB, RS232, PCI), HCI
  8. 8. Bluetooth Technology further alters the L2CAP packets so that the data may be transported over one of the om physical buses. This data is received by the link manager and baseband controller that assemble it into packets that are communicable using a Bluetooth link. i.c At the lowest level lie the link manager and baseband controller. The baseband controller performs all low level processing, og such as Bluetooth packet composition for transmission and packet decomposition upon reception. Running on the baseband nty controller is firmware implementing the link LINK SECURITY manager protocol, which handles link As with any communication link, there must control, is responsible for placing the device be security surrounding the data transfer in low power states, and performs any between two devices. With the frequency de encryption of the data transmitted. hopping and the timing involved in the hopping, is very difficult for an external device to eavesdrop on a Bluetooth link. stu However, there are some security risks from other Bluetooth devices already synchronized to an existing piconet and accessing sensitive information intended for w. another device on the piconet. Data encryption is used to prevent other devices and the piconet from ww eavesdropping on data transactions. The basic security procedure used over a Bluetooth link is based on a challenge response scheme. The authenticity of a
  9. 9. Bluetooth Technology Bluetooth device is determined a challenge capability combined with adhoc device sent by a verifier to a claimant and response connection and automatic service om to that challenge by that claimant device. discovery make it a superior solution for The response to the challenge is a function mobile devices and Internet applications. of the challenge, the claimant device’s Bluetooth finds applications in PC and Bluetooth address, and a secret key. The peripheral networking , hidden i.c secret key is known only by the verifier and computing ,data synchronization for the true claimant device and is not known to any other Bluetooth device. If the claimant address books and calendars, home og contains the correct secret key, the correct networking and home appliances such a response to the challenge will be calculated, s heating systems and entertainment and information between the verifier and devices. Asynchronous data channel and nty claimant can begin, otherwise verifier will up to three synchronous voice channels, detach from the claimant device. or one channel for both voice and data. This capability combined with adhoc ADVANTAGES AND APPLICATIONS OF BLUETOOTH device connection and automatic service Bluetooth can handle data and voice de discovery make it a superior solution for simultaneously. It is capable of mobile devices and Internet applications. supporting one between computers and stu their connected units. Bluetooth is an LIMITATIONS OF BLUETOOTH open standard for wireless connectivity with supporters mostly from the PC and The main drawback of Bluetooth is its cell phone industries. Its primary market w. limited connection distance and less is for data and voice transfer between transmission speeds. It supports data rates communication devices and PCs. It is up to 780kb/s which may be used for capable of supporting one asynchronous ww unidirectional data transfer. It is perfectly data channel and up to three adequate for file transfer and printing synchronous voice channels, or one applications. channel for both voice and data. This
  10. 10. Bluetooth Technology CONCLUSION 3. “Bluetooth” IEEE Microwave Magazine September 2002. om With its relatively low implementation costs, Bluetooth technology seems destined to dominate the electronic landscape, as humans worldwide will be able to form i.c personal area networks with devices and completely simplify the way in which they interact with electronic tools and og each other. In the years to come, Bluetooth will become a worldwide connectivity among nty electronic devices, leading to applications unthinkable by today’s technological standards. Because the radio frequency used is globally de available, Bluetooth can offer fast and secure connectivity all over the world. stu REFERENCES: 1. J.C. Haartsen et al. ,”The w. Bluetooth Radio System” IEEE pers. Commum.,Feb.2000 . 2. “Bluetooth in Wireless ww Communications” IEEE Communications Magazine June 2002