低功率蓝牙

For handheld computers or mobile phone handsets, power consumption limits the service period of the device, because it cannot be used effectively while it is recharging. Adding extra battery capacity adds volume, cost and weight to the device, all of which are undesirable. Manufacturers need an industrial handheld computer that can operate untethered for a complete work shift before needing an overnight recharge.

Most of the low-power industrial wireless devices now installed use proprietary radios. The only standardized radios now on the market offering extreme low-power performance are IEEE 802.15.4 radios, a standard promulgated by the Institute of Electrical and Electronics Engineers, which are used in some recent field transmitter products and in ZigBee-compliant products. Bluetooth radio technology, while very common in commercial markets, has been used in mains-powered industrial applications and in applications in which communication with handheld computers is important.

诸如ABB和Coronis之类的供应商已经适应了蓝牙收音机来传感应用，但丢弃了蓝牙堆栈。Coronis的Wavenis产品适应蓝牙，用于低功率应用，数据速率非常低。ABB的WISA无线传感器需要高数据速率，因此ABB为其设计了专用的无线电源。



Wibree announced

In October 2006, mobile telephone handset manufacturer Nokia announced plans to commercialize a new low-power complement to Bluetooth. The company formed yet another cutely named wireless technology consortium (Wibree,) and began work. The plan was to develop two different device types. “Dual Mode” devices such as telephone handsets and mobile computers would be able to communicate to all types of Bluetooth devices. “Stand-alone” Wibree devices would communicate only with Dual Mode masters, and would be able to operate for long periods (roughly one year) on battery power.

Nokia’s announcement was received respectfully, if not with enthusiasm. The formation of another consortium and associated technology development was, for many, not appetizing. Yet Bluetooth is the most pervasive form of wireless, due to its penetration into the 1 billion mobile handsets manufactured each year. When combined with Nokia’s large share of the handset market, this made Wibree a factor in personal area network (PAN) market road maps.

尽管技术开发仍按计划进行，但情况的政治现已改变。Wibree组织宣布将与更大的蓝牙特别兴趣小组（SIG）合并。它的技术将成为指定的超低功率（ULP），蓝牙的低数据速率扩展，并将纳入现有的蓝牙规范中。这些规格将在2008年初合并，并在今年下半年提供硅样品以及2008年的数量。

This addition means that Bluetooth will have three different physical layers by the end of 2008. The “Bluetooth Classic” (now IEEE 802.15.1), the new ULP, and the WiMedia Alliance ultra-wideband technology, which the Bluetooth SIG chose in 2006 to serve as its high-data-rate solution.

这项新技术不适合大多数现有的无线传感应用，并且无疑不适合工业应用。收音机的范围比IEEE 802.15.4小得多，而星形网络是唯一支持的拓扑结构。因此，ULP锅的直径只有20米，只包括七个设备，最大设备。现有的工业无线传感产品（例如ABB，Accutech，Coronis，Emerson和Honeywell）都支持更大的网络和更长的范围，即使仅在Star型网络中也是如此。

Medical device manufacturers should evaluate Bluetooth ULP in comparison to other solutions for product designs created after 2007, but manufacturers should expect no impact from Bluetooth ULP on their wireless sensing plans for the foreseeable future.

Harry Forbes,hforbes@arcweb.com, is a Senior Analyst at ARC Advisory Group Inc., in Dedham, Mass.