July 4, 2018
Engineers have multiple options for deciding which wireless technology to use for IoT or machine-type communications (MTC) applications. Each of this wireless technology has unique characteristics and potential benefits.
Some MTC standards are based on local area networks (LANs) such as Wi-Fi 802.11ah (HaLow) or personal area networks (PANs), such as ZigBee or Bluetooth. All these options require a gateway using another wireless technology to connect the devices to the main network.
LPWAN technologies like open standards-based Weightless, or proprietary technologies like LoRa and SigFox – require their own proprietary network.
None of the above options leverage existing cellular infrastructure fully. NB-IoT does not need separate gateways to connect devices. Devices connect directly to the base station as they are based on existing LTE standard thereby reducing deployment cost.
NB-IoT has several unique characteristics that make it a better technology option:
- Power efficiency
- Cost saving
- Easy Deployment
All IoT technologies are developed to save power, however they consume energy when the modem is transferring data and when doing signal processing. NB-IoT devices have a typical current consumption the order of 1 nA, which helps enable devices to operate for up to 10 years on a single charging cycle. NB-IoT also uses a simpler modulation scheme that consumes less power.
NB-IoT devices can single-chip design to lower the cost. Integrating the power amplifier and antenna switch simplifies routing by reducing the number of RF components in the front end. It also reduces the PCB size. Since a single tone transmission technique can be used in NB-IoT, a power amplifier with a low Peak-to-Average Power Ratio (PAPR) can be designed within the device, resulting in a system-level RF chip.
The main advantage NB-IoT is this can leverage existing cellular infrastructure for rapid deployment and scalability as this follows 3GPP LTE standard. As single regulatory body enforces the standard and interoperability across devices, technology adoption is easier.
NB-IoT possesses all the security measures currently present in LTE networks, including secure authentication, signaling protection, and data encryption.
3GPP TS 36.211 Release 13, V13.2.0 (2016-06) provides a physical channel and modulation specification The NB-IoT Narrowband Physical Uplink provides two choices for subcarrier spacing: 15 kHz and 3.75 kHz. 3.75 kHz provides deeper coverage to reach challenging locations, such as deep inside buildings, where there is limited signal strength. Data subcarriers are modulated using binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK).
Downlink (DL) modulation OFDMA, Uplink (UL) Modulation SC-FDMA. Data Rate 250 kbps in DL. 250 kbps in UL (multi-tone) and 20 kbps (single tone).Bandwidth 180 kH. Duplexing Technology Half Duplex and FDD. Latency 1.6 to 10 seconds.
Due to narrow 180 kHz bandwidth, LTE networks can accommodate a large number of IoT devices without impacting the performance of regular mobile devices. Usage of simplified downlink convolution channel coding instead of Turbo code results into a low complex baseband decoding process.
In order to use the spectrum resources efficiently, NB-IoT has been designed with three different operation modes: in-band, guard band and standalone.
i)In band deployment
NB-IoT can be deployed within the existing LTE spectrum. The main advantage is that it can be enabled very quickly.
ii)Guard band deployment
NB-IoT can be deployed within the guard bands of the 3G and LTE spectrum. Though these spectrums are designed to reduce interference, they can also be used for narrowband applications.
NB-IoT can also be used as a standalone deployment within its own dedicated spectrum. This option can be used for dense deployment.
For more details on NB-IoT NB-IoT Technology to revolutionize LPWA market