如何建立一个长距离、低功耗的物联网无线网络

　　如何建立一个长距离、低功耗的物联网无线网络

　　在不受管制的亚GHz频段创建链接，有越来越多的吸引力，为物联网（物联网）的工业应用系统的开发人员。低成本的微控制器，无论是32位或8位，高性能的亚GHz射频收发器相结合，开辟了有效的远程节点设计的机会。这降低了成本，通过减少网关设备需要的数量和规模更容易让物联网应用。

　　设计师也可以减少范围或数据速率，以提供更长的电池寿命，在某些情况下长达二十年。这可以大大减少在工业网络中更换电池的操作成本，可能有成千上万的节点。的能力，增加更多的节点没有显着增加运营成本是一个令人信服的理由，这样的亚GHz的设计。

　　Network architects have previously favored the 2.4 GHz band as this has standardized protocols such as Wi-Fi， Bluetooth， 6LoPAN and ZigBee with software and application support. However， the increased sophistication of sub-GHz devices with high performance 32-bit ARM microprocessor cores is allowing the chipmakers to provide more support for the devices even including real time operating systems. At the same time， standalone transceivers that include their own controller cores for sub-GHz protocols can be used with low cost external controllers to provide cost effective wireless links for IoT nodes. This gives the designer of the node tremendous flexibility in the architecture and implementation to achieve the best balance of range， power consumption and data rates.

　　The AX5243 from On Semiconductor， for example， is a single-chip， ultra-low-power， narrow-band transceiver for use in bands from 27 to 1050 MHz. The on-chip transceiver integrates an RF front-end with modulator， and demodulator， with the baseband processing in an embedded communication controller that enables user-friendly communication via the SPI interface. It operates from a 1.8 V to 3.6 V power supply for low-power designs and over an industrial temperature range of -40°C to 85°C.