Swapping photos, music and other data between your digital camera and your mobile phone through a wireless connection, instantaneously: Bluetooth Special Interest Group (SIG), a standardization organization for Bluetooth, has released its high-speed standard, called 3.0+ High Speed (HS). One characteristic of the new technology is that it can add IEEE802.11 (Wireless Local Area Network, or WLAN) to the media access control (MAC), physical and other layers of existing Bluetooth. The goal is to facilitate interoperability between Bluetooth devices, together with the high speed of Wireless LAN. Depending on the specifications of the Wireless LAN used, the peak data rate could be increased as much as eight times from the current 3Mbps level.
For people designing equipment with wireless
functionality, it will mean that chips, modules and all sorts of
components needed to implement both Bluetooth and Wireless LAN will be
a lot easier to use. Component cost can be reduced while simultaneously
reducing the development load for communication applications. For
example, 3.0+HS support can be implemented by merely adding software
with a standard-select function to existing components. Such software
has already been announced by Atheros Communications Inc of the US,
Broadcom Corp of the US and CSR plc of the UK.
However, 3.0+HS compliant devices cannot communicate with existing Wireless LAN devices. The upper-layer protocol is Bluetooth, which is different from the Transmission Control Protocol/Internet Protocol (TCP/IP) used by Wireless LAN (Note 1).
Notes 1: Existing Bluetooth-compliant equipment will be limited to the data rates defined under the older Bluetooth standard.
The function actually adding Wireless LAN in 3.0+HS is implemented via alternate MAC/PHY, or AMP. AMP consists of the AMP Controller, which controls the operation of the Wireless LAN MAC and physical layers, and the AMP Manager, which determines which communication system to use.
The AMP Manager is the most important, because it has a significant impact on the effective data transfer rate, power consumption and other characteristics. This is because it controls the timing of switching between Bluetooth and AMP.
Bluetooth has a low data rate, but current consumption is only a few tens of mA. Wireless LAN, on the other hand, is very fast, but also has a high current consumption of hundreds of mA. By building in settings to determine the optimal communications scheme, large power will be consumed even when transmitting small amounts of data. The specification does not define a specific switching method, so manufacturer implementation will have a direct effect on system performance.
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