先决条件–物联网中的数据链路层协议
1. LoRaWAN：
LoRaWAN属于MAC层协议，该协议是为大型公共区域网络而设计的。 LoRaWAN是使用Semtech的LoRa技术创建的。 LoRa和LoraWAN属于非蜂窝无线通信网络协议，遵循线性调频扩频调制(CSS调制)。
2. NB-IoT：
NB-IoT也被称为窄带IoT，它被认为是物联网的无线通信。 NB-IoT属于LPWAN(低功耗广域网)类别，具有连接需要少量数据，低带宽和长电池寿命的设备的能力。
NB-IoT是一种用于IoT设备和应用程序的窄带无线电技术，该技术要求以低成本实现远距离无线连接，并且分别消耗很少的电能以延长电池寿命。
LoRaWAN和NB-IoT之间的区别：
| COMPARISON | LORAWAN | NB-IoT |
|---|---|---|
| Modulation | LORAWAN uses chirp spread spectrum modulation. | NB-IoT uses Quadrature phase shift keying modulation. |
| Frequency | It uses 868MHz in Europe, 915MHz in North America, 433MHz in Asia (Unlicensed ISM bands). | It uses Licensed LTE frequency Bands. |
| Bandwidth | LORAWAN has 250KHz and 125KHz bandwidth. | NB-IoT has 200KHz bandwidth. |
| Maximum message/day | Maximum Message it can send per day is unlimited. | In this technology maximum message/day is also unlimited. |
| Maximum Data Rate | The maximum data rate in case of LoRaWAN is 50Kbps. | The maximum data rate in case of NB-IoT is 200Kbps. |
| Maximum Payload Length | In LORAWAN, the maximum payload length is 243bytes. | In NB-IoT, the maximum payload length is 1600bytes. |
| Range | The Range of LoRaWAN is 5 km in urban, 20 km in rural area. | The Range of NB-IoT is 1 km in urban, 10 km in rural area. |
| Interference Immunity | Interference immunity in case of LORAWAN is very high. | Interference immunity in case of NB-Iot is Low. |
| Authentication and Encryption | It supports AES 128b as encryption technique . | It supports LTE encryption technique. |
| Adaptive Data Rate | LORAWAN supports Adaptive Data Rate (ADR). | It does not support Adaptive Data Rate (ADR). |