【導(dǎo)讀】多點(diǎn)連接、語音與數(shù)據(jù)混合傳輸以及高抗干擾能力等方面。藍(lán)牙的開放性使藍(lán)牙停。車場管理系統(tǒng)無償使用藍(lán)牙這項(xiàng)技術(shù)，無需繳納專利費(fèi)用。示，用蜂鳴器和LED提示車輛進(jìn)出，用LED燈指示藍(lán)牙連接情況。研究目的和意義··························································································1. 國內(nèi)外研究現(xiàn)狀···································································&

　　

【正文】 濃厚的興趣，能系統(tǒng)的學(xué)習(xí)專業(yè)知識，了解本專業(yè)先進(jìn)知識的動向，并最終使自己成為一個(gè)對社會有用的人。 . .. 附 錄 附錄 A 外文資料 Bluetooth Bluetooth technology is named after Harald Bluetooth, a Danish king who managed to consolidate Denmark and a part of Norway in the 1900s. The choice for the name of this technology is a manifestation of how influential and central the panies from this region are to the telemunications industry. Bluetooth is a working technology that does not rely on user control or large amounts of power. By keeping the transmission power to an extremely low setting (1 milliwatt), Bluetooth is ideal for mobile battery operated devices. Moreover, Bluetooth does not rely on the user since it can automatically detect and municate with other Bluetooth devices without any user input. Bluetooth technology relies on two things, a radio frequency technology and the protocol software enabling it to transmit data to other devices. Bluetoothcapable devices can transmit data to other devices not within the line of sight of the user. It also enables different devices to municate using certain rules such as the amount of data that will be sent, the type of munication between the devices and the radio frequency or frequencies this munication will take place. These protocols ensure that Bluetooth devices experience the least amount of interference from other Bluetooth capable objects while municating with each other. Bluetooth RF Properties Low energy radio waves are the principal transmission system in Bluetooth working. The frequency of Bluetooth capable devices ranges from GHz to as high as GHz, a frequency range specifically reserved by international agreement for ISM or medical, industrial and scientific devices. Transmission Capabilities . .. Other devices in the market that use the same ISM band are garage door openers, cordless phones, baby monitors, etc and all these devices contribute to the increase in the risk of interference among Bluetooth devices. To avoid this, Bluetooth devices only use about 1 miliwatt of power in transmitting its signals. This makes the effective range of a Bluetooth device about 32 feet or ten meters and thus limits the chances of interference from other nearby devices. Nevertheless, the low transmission power requirement of Bluetooth devices make them capable of municating with other Bluetooth devices not within their range of sight. This means that a Bluetooth device can still connect to a personal puter for file transfers even if the puter is in an entirely different room in the house. Bluetooth is not a oneonone data transmission technology so it can municate with up to eight devices within its transmission radius at one time. A Bluetooth device will use at most 1600 different and randomly chosen frequencies every second within the course of its transmission to minimize the probability of other devices using the same frequency and to minimize interference time when it does coincide with another device using the same frequency. Picos or Personal Area Networks A Bluetoothcapable device ing into range with another one will first determine if it has data to share or mands to transmit. This happens automatically and without any user input. Bluetoothcapable devices municating with each other within an area form a pico or personal area work where devices integrate and s ynchronize their frequencyhopping to keep in touch with each other. With the use of a specific evice addresses in Bluetooth capable devices, it is possible to create multiple picos or personal area works within the same area. This means that since a cordless phone base unit and handset municate with each other using a specific address range range, they will not interfere with Bluetoothcapable devices in the same room. The Bluetooth work ignores any transmission from devices outside of its assigned address range. The addresses of these devices and the program that instructs these devices to listen and respond using a specific address range are programmed by the manufacturer to lessen interference and increase the efficiency in data transmission of Bluetooth devices. Since each device in a pico is synchronized in frequencyhopping, the risk of two picos interfering with each other by being in the same frequency at the same time is . .. very minimal. Moreover, since the picos change frequencies 1600 times every second, a collision between two picos will last only a fraction of a second. Corrective software in these Bluetooth devices will also correct any interferenceconsequent errors, thereby increasing the efficiency of work munication. Bluetooth Power Classes Bluetooth provides three types of power classes, although class 3 devices are not in general availability. Type Power Level Operating Range Class 3 Devices 100mW Up to 100 meters Class 2 Devices 10mW Up to 10 meters Class 1 Devices 1mW meters Bluetooth Security Bluetooth security is based upon device authentication, not user authentication. Each device is either trusted or untrusted. Bluetooth devices are identified by unique 48bit identifiers, much like Ether MAC addresses. Bluetooth Security Modes Bluetooth features three security modes. Mode Name Description 1 Nonsecure No security is implemented 2 Servicelevel security Access is granted to individual services 3 Linklevel security Security is enforced at a mon level for all applications at the beginning of the connection Bluetooth Security Levels Bluetooth features three possible security levels. . .. Mode Description 3 No authentication or authorization is required 2 Authentication is required。 authorization is not required 1 Authorization and authentication are required Bluetooth Security Weaknesses Bluetooth weakness include: The Bluetooth challengeresponse key generation is weak. This scheme may use a static number or a number for a period of time, which can reduce the effectiveness of the authentication. 2 、 Bluetooth39。s challengeresponse is simplistic. A oneway challenge for authentication is susceptible to maninthemiddle attacks. Mutual authentication via user verification should be used. The keys used by Bluetooth are weak. The initialization key needs to be more robust and the unit key is a publicgenerated key that can be reused. A set of keys should be used instead. The master key is shared between Bluetooth connections. This key is a broadcast and should have a better scheme than what is used. The encryption algorithm scheme utilized in Bluetooth uses a single algorithm and allows repeat authentication. A more robust method that limits authentication and increases the encryption should be used. Authentication encryption should be increased. Bluetooth implementations normally imit the PIN number range. A PIN number is usually only four digits and the scalability for large environments is difficult. Additional Sources of Information on Bluetooth Security 9 、 For more information on Bluetooth security, read Bluetooth Security at BlueTomorrow, Bluetooth Protocol and Security Architecture Review by Korak Dasgupta, or Overview of Ad Hoc and Bluetooth Networks. Bluetooth versus Infrared . .. 1 The major advantages of the Bluetooth technology over other munication technologies are its being cheap, wireless and automatic. 1 A data transmission technology parable to Bluetooth is IrDA or infrared munication much like what your remote control devices use to control the TV, stereo, air conditioner etc. The big drawback of this type of technology, however, is the requirement that the two devices establishing a connection must be within sight of one another for tr