LoRaWAN [/ˈlorawan/] n - LoRaWAN is a wireless protocol contrived for low-power, low-bandwidth, long-range communication. It is the right instrument when many small sensors lie spread over a wide ground, and cabling each one would be costly or unsightly.

Of Its Workings

• LoRa is the physical layer. [/ˈlɒræ ˈɪs ˈthɛ ˈphisɪkæl ˈlæiɛr/] n It employs chirp spread-spectrum modulation, which trades data rate for range and resistance to interference.
• WAN is the network layer. [/ˈwæn ˈɪs ˈthɛ ˈnɛtwɒrk ˈlæiɛr/] n End devices speak to gateways, which forward packets to a network server; the server minds routing, encryption, and integration.
• Classes of devices. [/ˈklæssɛs ˈɒf ˈdɛvɪkɛs/] n Class A devices sleep most of the time and listen only briefly after transmitting. Class C devices listen continuously but draw more power. Most sensors are Class A.

Of Its Place in a Data Center

• Roof and yard sensors. [/ˈrʌːf ˈænd ˈiærd ˈsɛnsɒrs/] n Weather stations, tank levels, fence contacts, or environmental monitors about the campus.
• Hard-to-wire corners. [/ˈhærdtɒwɪrɛ ˈkɒrnɛrs/] n A sensor in some far corner of a warehouse, or a mechanical room that has no Ethernet drop.
• Backup communication. [/ˈbækkʌp ˈkɒmmʌnɪkætɪɒn/] n A battery-powered LoRaWAN sensor keeps reporting even when the wired network is down, so long as the gateway has power.

Of Its Costs

• Low bandwidth. [/ˈlɒw ˈbændwɪdth/] n You are not streaming video; you are sending small packets every few minutes or hours.
• Latency and acknowledgments. [/ˈlætɛnki ˈænd ˈækknɒwlɛdgmɛnts/] n Class A devices can receive only just after they transmit, so remote control is slow and unreliable.
• Gateway dependency. [/ˈgætɛwæi ˈdɛpɛndɛnki/] n A dead gateway can silence a whole area. Contrive overlapping coverage, or at least gateway redundancy.

In These Pages

LoRaWAN appears in On the Making of Bespoke Devices as a connectivity option, and in Bespoke Devices for the Datacenter as part of the toolkit. For wired alternatives, see Modbus and Power over Ethernet.