Features of bluetooth technology Essay Example for Free

Features of bluetooth technology EssayThe logo for Bluetooth is plantd on Runes surrounding the legend of Harald Bluetooth. Bluetooth the technology is based on communication theory central to mans own personal space. Fundamentally Bluetooth operates within the Industrial, Scientific and Medical (ISM) slew at 2. 4 GHz. It is a short-range tuner communication standard defined as cable television replacement for a Personal Area Network (PAN) (see Bluetooth. Grolier Encyclopedia of Knowledge, pp. 87-94). Figure 1 is the Bluetooth Logo. A cable replacement standard has been defined because cables limit mobility of the consumer they are cumbersome to carry around, are easily lost or broken. Often connectors are prone to strong to diagnose failures or are proprietary. To counteract these limitations Bluetooth is designed to be light and portable. It can be embedded to take the riggers of physical knocks and shocks. It includes standards and protocols to make it mobile, robust, re liable and non limited to one manufacturer (see Bluetooth. Grolier Encyclopedia of Knowledge, pp. 87-94). The operating band also fits the goals of Bluetooth, imposing requirements as a cable replacement. The constitute needs to be alike(p) with cable. Reductions can be achieved by operating in the licence free 2.4 GHz ISM band, keeping backward compatibility wherever possible lowers the cost of ownership by avoiding upgrades and having a relaxed radiocommunication specification enables single chip integrated circuit solutions. It also needs to be as reliable and springy as cable and cope with errors and degradation caused by interference. For mobile devices it must be compact, lightweight, low power and easy to use (see Bluetooth. Grolier Encyclopedia of Knowledge, pp. 87-94). A. 1 absolute oftenness Hopping We film addressed the reasons for the Bluetooth without delving into the nuts and bolts of the technology to discover how it operates.For the majority of countries the I SM band used by Bluetooth is available from 2. 40-2. 4835 GHz, although some countries impose restrictions. In this band Bluetooth uses Frequency Hopping Spread Spectrum (FHSS) techniques in order to improve its immunity from interference (see J. Bray and C. F. Sturman, Bluetooth concern Without Cables, Prentice Hall). In unrestricted countries the radios hop in hoax random sequences around all available channels, this equates to 79 RF channels with a channel spacing of 1 MHz.Starting at a base frequency of 2402 MHz then the frequency of the channels, f, can be expressed as f =2402 + n MHz where, n, is the channel number with an integer protect in the range of 0 to 78. In restricted countries a limited frequency hopping schemes with just 23 channels is used and is catered for in the Bluetooth specification. Both hopping schemes have a 1 MHz channel spacing making it possible to design a simple radio interface whereby the baseband only has to specify a channel number and the radio multiplies this up to the appropriate frequency offset (see J.Bray and C. F. Sturman, Bluetooth Connect Without Cables, Prentice Hall). In this FHSS scheme there are 1600 hops per second, which is a hop every 625 s. Part of this hop timing is interpreted up by the guard eon of 220 s allowing the synthesizer time to settle. The frequency hopping implements time division multiplexing as shown in Figure 2. The basis of the scheme has the Master device transmitting in the first 625 us slot, k, and here the break ones back receives. In the next slot k = 1 the Slave is permitted to transmit and the master listens (see J.Bray and C. F. Sturman, Bluetooth Connect Without Cables, Prentice Hall).Figure 2 Frequency Hopping, master and knuckle down interact on corresponding slots The radio must be able to retune and stabilise on a new frequency within tight time constraints. This is pushed further when establishing a connection the hop rate can be shortened to every 312. 5 us. As the radio s are constantly hopping to different radio channels, this ensures that packets affected by interference on one channel can be retransmitted on a different frequency channel.To further enhance resilience both ARQ (Automatic Repeat reQuest) and FEC (Forward Error Correction) form part of the specification (see J. Bray and C. F. Sturman, Bluetooth Connect Without Cables, Prentice Hall). One drawback with the normal hop sequence is the time taken for production testing. Bluetooth ensures adequate frequency coverage with a test sequence allowing the radios to be tested at a faster rate (see J. Bray and C. F. Sturman, Bluetooth Connect Without Cables, Prentice Hall).