Deploying NB-IoT in smart city projects in China

Deploying NB-IoT in smart city projects in ChinaLow power WAN (LPWAN) is a fast growing wireless network for connected devices. LoRa and Sigfox are the first two LPWAN technologies that hit the internet-of-things (IoT) market. With its standardization completed last June, NB-IoT (narrow band IoT) has entered to heat up the market.

LoRa, Sigfox and NB-IoT represent two discrete groups of LPWAN technologies. The former two technologies use an unlicensed spectrum whereas NB-IoT operates in a licensed spectrum.

Licensed vs unlicensed spectrums

Generally speaking, LPWAN technologies that use licensed spectrums can provide guaranteed service delivery and reliability, easier deployment and support higher-speed two-way data transmission than those operating in unlicensed spectrums. The key disadvantage of licensed spectrum technologies over its competing unlicensed spectrum counterparts is higher cost.

Operating in a licensed spectrum that is regulated, NB-IoT can provide assured quality of service (QoS) and delivery with minimal risk of disruption. For those using an unlicensed spectrum, it will be harder to guarantee this QoS, as there will be other networks operating on the same unlicensed frequencies.

“The value of a licensed spectrum is the guarantee that a frequency range will be applied to a particular requirement,” said Hugh Ujhazy, associate vice president and IoT practice lead for Asia Pacific (excluding Japan) at IDC.

He added, “For NB-IOT, higher throughput use cases and reliability will be key.”

NB-IoT supports higher bandwidth applications and faster two-way communication speed than unlicensed spectrum technologies. NB-IoT is around 250kbps downlink whereas Sigfox transmits 8 bytes per message. Faster speed supports applications that rely on timely data transmission and firmware update over the air (FOTA).

On the deployment side, NB-IoT leverages existing GSM or LTE cellular networks with software upgrades to existing base stations. “This feature of NB-IoT as a software upgrade eases deployment over competition technologies like Sigfox ad LoRa,” he noted.

Nevertheless, NB-IoT is more expensive than LoRa and Sigfox in terms of devices, modules and connectivity.

An NB-IoT device and module costs around US$40 and US$5 respectively. For Sigfox, according to its operator Thinxtra, the device and module can be as low as US$20 and US$2. Sigfox’s network connectivity cost in Hong Kong is around HK$5 per device per year.

“Device costs are coming down but connectivity fee is still sitting above US$1 per device per year for Sigfox and slightly higher for NB-IoT,” said Ujhazy.

When choosing an IoT network, Ujhazy pointed out that coverage, cost, reliability and latency are some factors for consideration.

NB-IoT projects ramping up

NB-IoT uses existing cellular networks, minimizing the need to deploy additional infrastructure. More carriers are starting a foray into the NB-IoT space. China Unicom and China Telecom are two of them.

They have activated their base stations for IoT covering different cities in China, aiming to commercialize their networks on a nationwide level.