Comparison of NB-IoT and LoRa technology

[Fred Morgan]

There are many wireless communication technologies for the Internet of Things, which are mainly divided into two categories: one is Zigbee, WiFi, Bluetooth, Z-wave and other short-distance communication technologies; the other is LPWAN (low-powerWide-AreaNetwork, low-power wide area network), Namely WAN communication technology.

The rapid development of the Internet of Things puts forward higher requirements for wireless communication technology, and LPWAN, which is designed for low-bandwidth, low-power, long-distance, and massively connected IoT applications, is also rapidly emerging.

IoT applications need to consider many factors, such as node cost, network cost, battery life, data transmission rate (throughput rate), delay, mobility, network coverage, and deployment type. NB-IoT and LoRa have different technical and commercial characteristics, and they are also the two most promising low-power wide area network communication technologies. These two LPWAN technologies have the characteristics of wide coverage, multiple connections, low speed, low cost, and low power consumption. Both are suitable for low-power IoT applications and are actively expanding their ecosystems.

Introduction of NB-IoT and LoRa

1. NB-IOT

NB-IOT (NarrowBandInternetofThings, NB-IoT, also known as Narrowband Internet of Things) is a technical standard defined by the 3GPP standardization organization. It is a narrowband radio frequency technology designed specifically for the Internet of Things.

2. LoRa

LoRa (LongRange) is an ultra-long-distance wireless transmission scheme based on spread spectrum technology adopted and promoted by Semtech in the United States. The LoRa network is mainly composed of four parts: terminal (with built-in LoRa module), gateway (or base station), server and cloud, and application data can be transmitted in both directions.

Frequency band used by NB-IoT and LoRa

1. NB-IOT

NB-IoT uses licensed frequency bands and has three deployment methods: independent deployment, guardband deployment, and in-band deployment. The mainstream frequency bands in the world are 800MHz and 900MHz. China Telecom will deploy NB-IoT in the 800MHz frequency band, while China Unicom will choose 900MHz, and China Mobile may rebuild the existing 900MHz frequency band.

2. LoRa

LoRa uses the unlicensed ISM frequency band, but the usage of the ISM frequency band in different countries or regions is different. In the Chinese market, the China LoRa Application Alliance (CLAA) led by ZTE recommends 470-518MHz. The frequency band used by radio meters is 470-510MHz. Since LoRa works in an unlicensed frequency band, network construction can be carried out without application. The network architecture is simple and the operating cost is low. The LoRa Alliance is vigorously promoting the standardized Lo-RaWAN protocol around the world, so that devices that comply with the LoRaWAN specification can be interconnected.

Communication distance of NB-IoT and LORA

1. NB-IoT communication distance

The signal coverage of the mobile network depends on the base station density and link budget. NB-IoT has a link budget of 164dB, GPRS has a link budget of 144dB, and LTE has a link budget of 142.7dB. Compared with GPRS and LTE, the NB-IoT link budget has been increased by 20dB, and the signal coverage of the open environment can be increased by seven times. 20dB is equivalent to the loss of the signal penetrating the outer wall of the building, and the signal coverage of the NB-IoT indoor environment is relatively good. Generally, the communication distance of NB-IoT is 15km.

2. LoRa communication distance

LoRa provides a maximum link budget of 168dB with its unique patented technology. Generally speaking, the wireless distance range is 1-2 kilometers in the city, and the wireless distance can reach up to 20km in the suburbs.

NB-IoT and LoRa cost comparison

No matter how powerful the LPWAN protocol is, its low cost needs to be considered, otherwise they are not a viable IoT solution. LoRa has advantages in this regard.

The overall cost of the LoRaWAN module is around US$8-10, which is about half of the price of cellular LTE modules such as NB-IoT.

The higher the complexity of the NB-IoT network, the higher the costs related to intellectual property rights (in terms of authorized frequency bands), which increases the total cost of NB-IoT. Upgrading NB-IoT to advanced 4G/LTE base stations is more expensive than LoRa deployment through industrial gateways or tower-top gateways. As the market matures, the cost of LoRa technology is expected to drop further.