Low-power long-range (LPWAN) solutions for IoT and M2M
Low-power long-range (LPWAN) solutions for IoT and M2M

In this page, we have collected the most frequently asked question about NB-Fi and WAVIoT. If you can’t find an answer to your question do not hesitate to let us know.

NB-Fi questions

What is NB-Fi and what makes it such a great technology?

NB-Fi treated as Narrowband Fidelity is a proprietary LPWAN protocol that uses DBPSK on physical layer for signal transmission with sophisticated mathematics and coding to do wide-area IoT networking. WAVIoT uses narrowband approach to get up to 5 000 channels with 100 Hz bandwidth for each node within 500 kHz on 868 MHz frequency. Narrowband and high energy for each bit of transmitted data provide excellent link budget of up to 194 dBm while our high-tech gateway ensures -154 dBm sensitivity and great noise immunity.

WAVIoT made it possible to work with a broader family of transceiver chips like Semtech, TI, Axsem, SL etc.

What is the capacity of a gateway in terms of nodes supported?

WAVIoT NB-Fi operates up to 5 000 channels with 100 Hz bandwidth for each node within 500 kHz on 868 MHz frequency. Which basically means 5 000 nodes may be transmitting simultaneously to the one gateway at a given point in time. Provided that most of these LPWAN sensors transmit data once-twice per day, or on the event, it gives us an unrivaled number of more than 5 mln nodes intra-day. The computing and calculation power of our GWs is more than enough for all your existing and future needs.

Is the network bi-directional?

Yes, our network is bi-directional. Moreover, we have developed and already operate full-duplex IoT gateways, which means it can receive and transmit simultaneously (UpLink and DownLink). What we have already implemented, for example, tariffs in our smart electric meters can be reprogrammed remotely, plus an operator is able to cut/reduce the voltage remotely.

Read a press release on full duplex launch 

What is the average latency uplink and downlink?

An average uplink latency is 30 seconds, as or downlink it is 60 seconds.

What is the real bandwidth available for uplink/downlink?

As for standard modification, we operate in 868 MHz frequency, or 500 kHz bandwidth is available for the gateway. Though we have a lot experience of adjusting it to the local requirements which vary in different countries.

What about the back office interface? Can we build our own applications?

We develop back-end and front-end on our own in order to ensure it best fits our purposes. If we go into a full-scale project aiming to build an LPWAN network for our customer in any country all the required software solutions (Back- and Front-end) may be provided as a turn-key solution. For the beginning and/or small-scale project, the easiest and most common approach that we use is a RESTful protocol HTTP Get or API. In this context, we would like to emphasize that we are quite flexible in terms of the framework which may be agreed for such cooperation. Other details need to be discussed at a further stage.

How can we develop our own node applications, what node APIs and/or reference design do you provide?

You are welcome! WAVIoT is ready to open source code of NB-Fi protocol to its technological partners and allocate relevant technical support to let you develop your own nodes based on our technology.

Some technical specs:

  • WAVIoT NB-Fi protocol uses DBPSK on physical layer of signal transmission;
  • End-nodes transmit radio signal in 10 – 500 kHz bandwidth;
  • Minimum bit rate of 50 baud+ (8-10 bits per second);
  • Link budget available 184 -194 dBm;
  • Output power up to 25dBm (with FEM);
  • TX 250mA @ 27Bm, 90mA @ 16dBm, 44mA @ 14dBm;
  • Sleep mode with RAM retention and wake-up timer running 1.5 μA;
  • RF transceiver operates over a wide frequency range including 315MHz, 433MHz, 470MHz, 500MHz 868MHz, 915MHz in the license-free Industrial, Scientific and Medical (ISM) frequency bands.

How is structured your price listing?

We believe that our cost and price profile is another great advantage for a potential partner. For example, you may well see that our end-user device: integrated smart water meter is priced at only USD 21.99, while should you go to other well known IoT connectivity providers (Link Labs, NWave etc.) for example there is just a development kit which is far away to be a ready-to-use device available at USD 29, or Ingenu – no products or clear prices at all.

Considerations on NB-Fi and LoRa

Probably you have already heard a lot about LoRa. We collected the most important considerations about LoRa and compare it to the NB-Fi.

Why WAVIoT do not use LoRa?

We have developed a smart LPWAN protocol. When designing NB-Fi we considered all pros and contras and took into account a lot of factors which will reflect our technology and business as well. We made a decision to go our own way and make proprietary protocol based on narrowband approach.

For the detailed description why WAVIoT uses proprietary LPWAN NB-Fi protocol instead of LoRa please kindly read through the article and relevant white paper.

LoRa gateway is relatively cheap.

The problem with small gateways in such regard really lies in limited wide-area coverage features. It is much easier to maintain a smaller number of gateways then to monitor a small army of short range base stations. As regards to the cost issue, you may well investigate that LoRa based solutions are not cheap enough when we talk about multi-node networks. The radio module is priced at USD 29.00 and it is far away of being a ready-to-work device as was mentioned above. At the same time, all electronic part in the WAVIoT’s Smart Water Meter SWM-1 cost USD 8.00 on large volume orders.

WAVIoT implementation and use case experience proves that a client or end-user does not care about the technology, protocols, and other complex questions. The client needs usability and best price available. Especially when we talk about such traditional LPWAN applications as smart meters. No one would be willing to pay any given extra dollar for these kinds of end-user devices.

LoRa crystal accuracy requirements is low, the precision of ±30 ppm can satisfy the communication needs.

In the first instance, 30 ppm crystal gives an ability to work minimum at 1.2 kbps. WAVIoT data rate is about 8-12 bps. The difference is about 100 times. This gives 20 dBm difference. Each 20 dBm increases signal range 10 times or allow to penetrate 2 additional concrete walls.

Secondly, there is no sense to use 30 ppm crystals. Those times when crystals were expensive passed a long time ago. 0.5 ppm crystal cost is only USD0.5.

LoRa has adjustable spreading factor, for a variety of situations, strong anti-jamming capability.

Spreading Factor is the same as ADR. Different spreading factor gives you different data rates. Please refer to the next statement.

In order to improve gateway capacity and power consumption ADR is needed to set different communication rates.

ADR is an ability to transmit at the different data rate. Transmissions at two different data rates can theoretically work in one channel. The more data rate you have the shorter is your working distance. ADR was invented by LoRa because to solve the extreme lack of channels issue. Practically ADR can increase the capacity only by 2 times. We do not see much difference between 4 and 8 channels because we provide 5,000 channels in 100 Hz bandwidth.

LoRa supports high data rate 0.3 ~ 100 kbps.

Data rates above 300 bps give too short distance. It will require too many gateways to cover the whole city. In a case of direct comparison between LoRa and NB-Fi network at the real field, there will be a clear acknowledgment of our statement. Want to try? Let’s do it!

LoRa support mobile terminal access.

WAVIoT can do it as well.

LoRa can implement the positioning feature.

We aim to release geo-positioning in course of 2016 on our gateways. At the moment, there is still no proven expectations when LoRa vendors start shipping gateways with geo-positioning.

LoRa has an open standard communication protocol.

LoRa does not have open standard communication protocol to be completely honest. LoRa has opened only transport layer but not opened Physical and MAC layers. That’s why you can only work with Semtech transceivers SX1279 and SX1301 demodulators for these gateways. You can not work receive LoRa signals without SX1301 or SX1276.

NB-Fi is an open source long-range protocol for massive low-power IoT application.

LoRa selectivity considerations.

The concept of “selectivity” is important when analyzing the interaction of multiple non-coordinated systems of the same type. Poor “selectivity” may cause the damaging interference of a “same system” to be significantly worse than a different type of system. For example, a LoRa system has a much worse effect on a different LoRa system than a Sigfox or WAVIoT system would have on a LoRa system.

An interfering spread spectrum LoRa waveform that has no “selectivity” actually is a lot worse. For example, a packet from a private LoRa network will damage packet from public LoRa network. The result is that a transmission from a LoRa is up to 100x more damaging than any other noise source of the same power level.

LoRa interference considerations.

LoRa gateways can detect simultaneously preambles corresponding to all data rates on all IF3 to IF10 channels. However, it cannot demodulate more than 8 packets simultaneously. This is because the architecture separates the preamble detection and acquisition task from the demodulation process. The number of simultaneous demodulation is 8.

Lora gateways can check whether the packet belongs to the network only after demodulation occurs. Thus, any alien Lora packet blocks reception of own packets on this specific channel on the gateway until the end of the packet. If an alien node sends Lora packets non-stop, then the channel on the gateway will be constantly blocked. Thus, any curious person can legally put eight non-stop transmitting LoRa nodes on the roof of the high building in the city and block all 8 channels of the public LoRa city network.

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