Does Bluetooth Really Work?

Nick Barrett
Brandon Lee



Bluetooth Technology is based on a three-year effort to standardize a compatible wireless “PLAN” solution.  PLAN, stands for Personal Local Area Networks and the objective was to replace cables on devices such as; PDAs, cell phones, MP3 players, and digital cameras.  Other important applications are to connect printers to handheld devices, and to act as a controller for PDA related wireless technologies. 

            In addition, the 1.0b specification that Bluetooth is based on is flawed.  The specification was not fully identified and was plagued by various bugs that hurt performance.  Initial Bluetooth products were not inter-operable due to mismatched chipsets.  Navin Sabharwal of Allied Business Intelligence points out, “This was always a concern for a technology that would be implemented by dozens of different vendors into a variety of different products”.  For that reason, many companies, including Microsoft, were delaying their Bluetooth implementation efforts until an appropriate revision is released. 

            In addition to interoperability problems, there were basic flaws in the way that Bluetooth works.  It works within the same wireless communication radio frequencies as the ISM bands of the 802.11 standard, and because of this, the two technologies can interfere with each other.  For instance, a Bluetooth device operating in the same area as a wireless network will experience delays and performance issues.  In addition, the 802.11 standard utilizes CSMA/CA (Collision Avoidance) technology, which means that it cannot transmit until the media (radio frequency) is clear.  Therefore when a Bluetooth device is present inside a wireless network, performance can be seriously hindered.  This is particularly true because Bluetooth devices operate at only 1 megabit per second.  This problem is becoming less serious with the advancements in the 802.11 standard.  As wireless moves to the 5GHZ download frequency, it will leave the 2.4GHZ upload frequency less congested for Bluetooth devices.  The low amount of bandwidth involved with Bluetooth also posed another problem; several Bluetooth devices operating in the same PLAN will actually interfere with each other.  In the instance of mice and keyboards, key stokes or mouse movements could actually be lost, this present a serious QoS issue.

            In 2005, the Bluetooth Special Interest Group (SIG) is going to focus on fixing QoS problems and address multi-device interactions.  Advancements such as making Bluetooth understand that print jobs can wait a second, while mouse movements cannot are in the mix.  These advances will be part of Bluetooth 2.0+EDR.  This version of the protocol boasts a 3 megabit transfer rate, as well as the ability to be backwards compatible with 1.0, and 1.2.  Remaining backwards compatible is going to be a focus of the Bluetooth SIG, because they credit this with the popularity of their major competition, IEEE 802.11.  Further advancements will include running more slave devices off of one master node.  Currently, only 7 Bluetooth compatible devices can be run off of one master.  The plan is to increase this number to 255 in 2005.  This advancement will pave the way for complex Bluetooth networks, such as home security systems, and home automation of devices.  Looking forward to 2006, the Bluetooth SIG is looking to extend the range of very low powered Bluetooth sensors.  They are looking to get to a range of about 100 meters. 




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