Dajbych.net


IoT wireless networks

, 4 minutes to read

In­ter­net is a net­work for servers, desk­tops, lap­tops, tablets and mo­bile phones. IoT is a net­work for mi­cro­con­trollers. The mi­cro­con­troller can com­mu­ni­cate via Eth­er­net, Blue­tooth, Wi-Fi or GSM, but none of the tech­nolo­gies were orig­i­nally de­signed for bat­tery-pow­ered mi­cro­con­trollers. There are other op­tions you can con­sider dur­ing de­sign­ing your hard­ware so­lu­tion. They are de­signed specif­i­cally for em­bed­ded sys­tems.

Sigfox

Sig­fox is a wire­less wide area net­work oper­at­ing on 868 MHz in Eu­rope and 902 MHz in the US. Te net­work mod­ule is very power ef­fi­cient and in­tended to be used by bat­tery pow­ered de­vices. One Sig­fox mod­ule can trans­mit 140 mes­sages per day with a pay­load of 12 bytes and re­ceive 4 mes­sages per day with a pay­load of 8 bytes.

A Sig­fox mod­ule has its unique ID which must be reg­is­tered to lo­cal car­rier which charges cus­tomers for reg­is­tered de­vices. Mes­sages are stored in Sig­fox’s dat­a­cen­ter and can be picked up via In­ter­net HTTP API. Mes­sages re­ten­tion is 3 days. This ap­proach is very prac­ti­cal be­cause it ex­pects that data are pro­cessed in the cloud. For in­s­tant mes­sages de­liv­ery Sig­fox na­tively sup­ports Azure IoT Hub and Azure Event Hubs.

Sig­fox is ideal for upload­ing sen­sor mea­sure­ments. It is not de­signed for send­ing im­ages. Num­ber of mes­sages per day is re­stricted be­cause the fre­quency is un­li­censed thus one de­vice can­not op­er­ate more of­ten than 1 % of a time. Down­link is not a push no­ti­fi­ca­tion. The de­vice must ini­ti­ate the re­quest. Ad­di­tion­ally, down­link tar­iffs are not in­cluded in ba­sic tar­iffs. Sig­fox is a global net­work. A device reg­is­tered in one coun­try is roamed in an­other coun­try without ad­di­tional cost.

LoRa

LoRa is a wire­less wide area net­work op­er­at­ing on 169, 433 or 868 MHz in Europe or 915 MHz in the US and Canada. One LoRa de­vice can trans­mit or re­ceive 140 mes­sages per day with a pay­load of 52–220 bytes. Mes­sages are sent to your In­ter­net HTTP end­point. Per­ma­nently pow­ered de­vice can use down­link like a push no­ti­fi­ca­tion. A device reg­is­tered in one coun­try will not op­er­ate in an­other coun­try be­cause you must reg­is­ter the de­vice to each car­rier.

LoRa is ideal for upload­ing sen­sor mea­sure­ments and re­ceiv­ing com­mands. LoRa is not de­signed for send­ing im­ages or po­si­tion data. LoRa net­work does not have In­ter­net peer­ing. End­point ser­vices may vary. They are op­er­ated by each car­rier in­de­pen­dently.

NB-IoT

NB-IoT is stan­dardized in LTE Cat NB1. It op­er­ates on li­censed fre­quency. It can be de­ployed by a car­rier op­er­at­ing LTE net­work just by a soft­ware up­date. De­vice is re­quired to have a power con­nec­tiv­ity or Li-SoCl2 bat­tery. Net­work mod­ule does not need a reg­is­tra­tion. Net­work band­width is suitable for send­ing im­ages, but cur­rent modems has typ­i­cally 512kB buffers. The net­work re­quires your back­end have a pri­vate IP ad­dress and UDP com­mu­ni­ca­tion. In­te­gra­tion is the most dif­fi­cult, but it opens the most pos­si­bil­i­ties.

NB-IoT is the only wire­less net­work con­nected to the In­ter­net di­rectly. The de­vice can open UDP con­nec­tion to any In­ter­net server. TCP and TLS are planned and will be avai­l­able in the fu­ture. It can be used for re­mote de­vice firmware up­grade. It tar­gets en­ter­prise cus­tomers, but there are some Rasp­berry Pi NB-IoT shields with mi­cro SIM socket. Avai­l­abil­ity de­pends on car­ri­ers in your coun­try.