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Bluetooth

This discussion is based upon SystemView Application Note AN129 Bluetooth System Simulation.

In 1998, Ericsson, IBM, Intel, Nokia, and Toshiba formed a special interest group to examine uses for ISM. Their intent is to create an open standard, which will enable seamless voice and data transmission in the ISM band.

ISM has been authorized in three frequency bands. Each of these bands can be used to implement either analog or digital cordless systems. However, most interest appears to be in digital SS systems.

Frequency Band Spectrum Applications
902 928 MHz 26 MHz Licensed vehicle location systems [2 kW fixed, 15 W mobile], old microwave ovens [750 W], industrial heaters 50-100 kW, military radar [1 MW], spread spectrum [1 W]
2.4 2.4835 GHz 83.5 MHz Microwave ovens [900W], spread spectrum [1 W]
5.725 5.85 GHz 125 MHz Spread spectrum [1 W], licensed users [10 W]

Of the three bands, only the 2.4 GHz region has been set-aside for unlicensed use in Europe.

Some of the regulations governing these bands include:

DS-CDMA

Minimum 6 dB bandwidth: 500 KHz

Maximum peak output power: 1 watt

Maximum radiated signal: 6 dBi

FH-CDMA

Minimum hopping channel separation: 25 KHz

A minimum of 50 hopping channels in the 900 MHz band

A minimum of 75 hopping channels in the other bands

Maximum peak output power: 1 watt

Maximum radiated signal: 6 dBi

Bluetooth is a short-range wireless link that hopes to replace much of the proprietary cables used to interconnect equipment. The objective is to integrate mobile phones, PCs, handheld computers, and other peripherals. Some of its characteristics are:

  • A maximum of 8 devices can be linked to form a piconet
  • Operate in the unlicensed 2.45 GHz ISM band
  • Uses binary FM modulation and TDD
  • Gross data rate of 1 Mbps
  • Maximum data transfer rate of 721 Kbps
  • Spread spectrum uses 1600 hops per second

Spectrum spreading can be used at power levels up to 100 mW. Spreading is accomplished by using 79 carriers evenly spaced from 2.402 to 2.480 GHz. The maximum frequency-hopping rate is 1600 hops/s. The nominal link range is 10 centimeters to 10 meters, but can be extended to more than 100 meters by increasing the transmit power.

Bluetooth Model


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