如何建立一個長距離、低功耗的物聯(lián)網(wǎng)無線網(wǎng)絡(luò)

　　在不受管制的亞GHz頻段創(chuàng)建鏈接，有越來越多的吸引力，為物聯(lián)網(wǎng)（物聯(lián)網(wǎng)）的工業(yè)應(yīng)用系統(tǒng)的開發(fā)人員。低成本的微控制器，無論是32位或8位，高性能的亞GHz射頻收發(fā)器相結(jié)合，開辟了有效的遠(yuǎn)程節(jié)點(diǎn)設(shè)計(jì)的機(jī)會。這降低了成本，通過減少網(wǎng)關(guān)設(shè)備需要的數(shù)量和規(guī)模更容易讓物聯(lián)網(wǎng)應(yīng)用。

　　設(shè)計(jì)師也可以減少范圍或數(shù)據(jù)速率，以提供更長的電池壽命，在某些情況下長達(dá)二十年。這可以大大減少在工業(yè)網(wǎng)絡(luò)中更換電池的操作成本，可能有成千上萬的節(jié)點(diǎn)。的能力，增加更多的節(jié)點(diǎn)沒有顯著增加運(yùn)營成本是一個令人信服的理由，這樣的亞GHz的設(shè)計(jì)。

　　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.