NB-Fi is an LPWAN protocol that supports secure bidirectional communication for Internet of Things (IoT), machine-to-machine (M2M) and Industrial Internet of Things (IIoT) applications. NB-Fi makes it possible to realize the enormous potential of the Internet of Things by collecting and analyzing data from end devices for analytical, accounting, billing and ERP systems.

NB-Fi technology ensures wireless communication between devices in hard-to-reach places over long distances in dense urban areas, being perfectly fit for the building of IoT networks, deployment of automated metering systems for utilities, Smart Grid and Smart City projects, wireless solutions for industrial, agriculture, monitoring and alarm systems. 

NB-Fi is an open standard with disclosed format of NB-Fi messages and relevant technical data required for manufacturers to produce compatible IoT end devices.

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One of the advantages of Narrowband systems, such as NB-Fi (“Narrow Band Fidelity”), is the effective use of radio frequency spectrum. The width of one NB-Fi frequency channel starts from 50 Hz. NB-Fi devices use the 50 kHz bandwidth for Uplink messages and the 100 kHz bandwidth for Downlink messages, which are only small channels inside the allowed license-free ISM bandwidth. Thousands of NB-Fi channels can be accommodated simultaneously within these bandwidths. The narrowband signal and high energy per bit of transmitted information provide for an excellent energy potential for the link budget and a high noise immunity.

Key advantage of the highly sensitive NB-Fi base station is its ability to receive a signal with a low SNR – down to zero, i.e. when the signal level does not exceed the noise level. Base stations use advanced filters to provide an unrivalled level of dynamic range of a signal.

NB-Fi base stations can process thousands of channels simultaneously, digitizing the entire bandwidth in real time and receiving the messages which were sent at different data rates.

NB-Fi Spectrum

NB-Fi wireless protocol for IoT devices is designed for secure data exchange with full end-to-end encryption between the end devices and the server, and ensures confidentiality and integrity of the transmitted information.

NB-Fi is a LPWAN protocol that supports secure bidirectional communication for Internet of Things (IoT), machine-to-machine (M2M), Smart Grid, Smart Utilities, Smart City and industrial applications. The NB-Fi protocol is optimized for low power consumption and is designed to support large networks with millions of autonomous devices. WAVIoT base station with bidirectional communication powered by NB-Fi technology not only gathers data from utility meters, sensors and gauges but also allows controlling them. This requires the highest level of data security to protect the integrity and confidentiality of messages in both directions, which is implemented in the NB-Fi protocol.

NB-Fi protocol is based on encapsulation principle of network protocol layers. The lowest communication protocols layer is the physical layer that is responsible for receiving and transmitting of radio signals and controlling of IoT devices. The MAC layer is responsible for protecting of the transmitted data from interference in the wireless communication channel with non-cryptographic methods (using error correction codes), however the MAC layer does not guarantee delivery of the messages. The SC layer (Secure Channel layer) is used to ensure secure communication between the device and the server. Finally, the transport layer is used to represent application data in the packets that can be processed by the SC layer.

The NB-Fi security is based on well-established methods: use of standard algorithms and end-to-end encryption.

NB-Fi protocol uses a key system – each NB-Fi device has a unique 256-bit root key. Based on this root key, the diversification function generates two keys for the Uplink and Downlink channels. These keys for each channel are used to obtain the 256-bit master keys for data protection. In addition, two separate master keys are generated for the message authentication code. Master keys are used only once to generate the data keys, and after that the master keys are updated. Data keys can be used to encrypt no more than 256 packets.

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CTR and OMAC modes based on AES-256 are used for the two-key encryption scheme and for the message authentication code. Other symmetric block cipher algorithms with 256-bit key can be used, if required.

To ensure the security and integrity of NB-Fi transport layer, an authenticated encryption with associated data (AEAD) scheme is used.

The distinction of NB-Fi protocol is the absence of the guarantee for the package’s delivery. This limitation is caused by the physical limitations of wireless transmission and the low isotropic radiated power of the end devices. It distinguishes the implementation of NB-Fi protocol, for example, from the Datagram Transport Layer Security (DTLS) protocol, where the data keys on the both side after the handshake do not change during the data transfer, therefore the skipping of the packet or changing of their sequence order does not require additional key synchronization.

NB-Fi protocol is designed to establish a secure channel between the end device and the application server controlled by the network operator. Such communication channel shall guarantee security and integrity of messages not only during their wireless transmission, but also during their transmission through the Blueberry Cloud (alongside HTTPS).

To ensure cryptographic protection of information at the presentation layer, a scheme similar to the transport layer’s scheme is used. In this case, no keys used at the transport layer can be used at the presentation layer, and it is impossible to disable the encryption or change the encryption algorithm.

NB-Fi standard supports bidirectional (Uplink and Downlink) communication. This is primarily required for end devices like electricity meters, where a Downlink channel allows controlling the meter: time synchronization, tariff schedule update, load relay switch off etc. NB-Fi transceivers built into end devices, together with sophisticated signal reception algorithms, ensure almost symmetrical communication channel in both directions.

All our devices with bidirectional communication support adaptive data rate. If the signal strength is good, devices will automatically switch to a higher data rate. This allows using the spectrum efficiently and reduces the consumption of power necessary for transmitting data.

NB-Fi standard supports up to 4.3 billion devices in a single network with a 32-bit ID for each device. NB-Fi does not use IP addressing (IPv4, IPv6) in order to optimize the payload. IoT devices (such as sensors and gauges) can transmit tiny few-bytes data packages. The minimum size of an IP header is 20 bytes, thus the Non-IP Data Delivery (NIDD) approach allows developing simpler and cheaper devices. Data exchange between devices and third-party applications is possible through the Blueberry Server as a custom solution.