Personal area network

A personal area network (PAN) is a specialized type of computer network, which benefits from extremely short range. Among its applications is replacing the cables between a computer and its peripherals, so minimal range is desired to avoid interference with other nearby computers.

Body Area Network

The first application proposed, however, was linking computing elements on (or in) different parts of a living body. This is now called a Body Area Network, as a subset of PAN.

In the context of a single-person network, as with wearable computers,

The trick is to allow "wearable" electronic devices to exchange data by capacitively coupling modulated picoamperes currents through the body. A low frequency carrier (below 1 MHz) is used so very little energy is radiated outside the body itself, minimizing interference and remote eavesdropping. A PAN device electrostatically induces picamp currents into the body which is used as a "wet wire" to conduct the modulated currents."

Wireless PANs

Bluetooth was probably the first widespread Wireless PAN (WPAN) industry standard. IEEE, however, has taken up formal standardization for the Bluetooth and other PAN application areas. IEEE created the 802.15 group to address the perceived limitations of that and other wireless technologies:

• "balancing cost with range and bandwidth
• "offering coexistence with other wireless devices
• "providing security in roaming environments."

IEEE 802.15

In the original specification, PANs, as defined by 802.15, have a range of 33 feet, which may be excessive in some applications. Their roaming concerns may address this. An 802.15 PAN uses a time-slot technology to support up to 254 devices, of which one is the timing beacon for the self-organizing network. It addressed two classes of requirements, using 2.4 GHz transmission:

A number of task groups were subsequently formed.

• IEEE 802.15.1 is a formal standard based on Bluetooth.
• IEEE 802.15.2 deals with coexistence of WLANs and WPANs
• IEEE 802.15.3 focuses on high-bandwidth (about 55M bit/sec), low-power MAC and physical layer
• IEEE 802.15.4 deals with low-bandwidth (about 250K bit/sec), extra-low power MAC and physical layers
  • Task Group 4e extends medium access control for industrial market applications, and modifications being proposed within Chinese standardization. The application spaces included are: " Factory Automation, Process Automation, Asset Tracking, General Sensor Control (Industrial/Commercial, including Building Automation), Home Medical Health/Monitor, Telecom Application, Neighborhood Area Networks, Audio."
  • Task Group 4f defines physical layer extensions for bidirectional RFID
  • Task Group 4g, "Smart Utility Networks", considers "very large scale process control applications such as the utility smart-grid network capable of supporting large, geographically diverse networks with minimal infrastructure, with potentially millions of fixed endpoints."
• IEEE 802.15.5 provides enhancements for mesh networks
• Task Group 6 (Body Area Network--BAN), formed in 2007, "is developing a communication standard optimized for low power devices and operation on, in or around the human body (but not limited to humans) to serve a variety of applications including medical, consumer electronics / personal entertainment and other."
• Task Group 7 will develop a physical layer based on visible light.