The DECT Forum hosted a series of NR+ webinars - these are the questions received during the webinars and other occasions:

Technical and performance questions on the standard

How well is a large-area distributed network with low repeater density supported? In some cases, it is difficult to find points to power the repeaters and the battery life needs to be several years.
There are many factors in play here and therefore the answer depends on the actual deployments. In the report we link to below we have some estimates that were simulated by the VTT (Technical Research Centre of Finland) for the deployment scenario defined by the ITU-R IMT-2020 technology requirement and evaluation guidelines (ITU-R M.2410-0 and ITU-R M.2412-0).

Both 23 and 10 dBm TX power were analyzed, with a test setup of having the gateway (FT-node) distance at 500m, the number of used channels being 5 (8.64 MHz) in total and reference sensitivity –99.7 dB. Table 4 in the report illustrates the performance in terms of packet error rate in this scenario.

The findings were:

• From a density point of view, more than 4M devices can be supported in a square kilometer area.
• With 115 devices in a square kilometer area, the system is still operating reliably. To put this into some perspective, this is less than one device in the area of a football field.

The described simulation can give a good grip on the performance, still keeping in mind that the figures are highly dependent on assumptions made.
For the full report, please visit:  https://publications.vtt.fi/julkaisut/muut/2021/VTT-R-00367-21.pdf


How does DECT NR+ compare to a 2.4GHz connection like Bluetooth Low Energy (BLE) in regard to range and throughput? Would a logical use case be DECT NR+ technology applied in a remote control for mobile machines?

As a rule of thumb, the DECT NR+ standard has better range and throughput than Bluetooth LE. The standard utilizes the forward-error-correction algorithms for long range operation and adapts and avoids radio interference. In the 1.9 GHz DECT band there is much less congestion than on the BLE 2.4GHz ISM band. DECT NR+ for machine control is a logical use case. The 5G term here is used to describe ultra-reliable low latency communications.


What is required to achieve the 3km range, in which frequency range and at what bandwidth?

To achieve the 3 km range, a line of sight is needed. The radio frequency used during testing was the 1.9 GHz band for Europe (1880-1900 MHz) and the bandwidth used was 1.728MHz. This frequency band in Europe is license exempt and dedicated to DECT systems. Therefore, operation is allowed without a specific frequency license, but only DECT systems are allowed to be used. 


What is the latency in the mesh operation? Is it easy to calculate between the number of hops?

The end-to-end latency of the mesh topology at the radio level is the sum of hops on normal operational conditions. The link latency to deliver a packet from device to the next hop is product, product configuration, and application dependent, and of both the next hop and the device transmitting the data. Additionally, the link latency may vary from time to time due to fast layer 1 HARQ re-transmission. 


Does DECT NR+ support antenna diversity?

Antenna diversity is supported by the standard. What needs to be noted is that the initial device from Nordic Semiconductor has a single antenna connector, and antenna selection would need to be done with a separate chip.


Will the solution from Nordic Semiconductor and Wirepas (Wirepas Connectivity 5G Mesh) support all features of the DECT NR+ standard, or only a part of it?

The simple answer here is no, as the features chosen for products are dependent on the use cases. It is highly unlikely that any solution will require all these features. As the standard can serve many different verticals, smart metering/grid, building management, Industrial IoT, Professional Audio and PMSE, the features needed can vary a lot between different products and solutions. The initial focus is on massive Machine Type Communications (mMTC).

Market preparedness and commercial questions

How will the units be marketed and presented in order to make sure that the units use the same frequency, since the standard can support 450mhz to 6Ghz?

Equipment branding and marking to support each frequency band is a topic that the DECT Forum plans to provide some guidance on in the future. From the standards’ point of view, frequency band support is explicit in signaling - i.e. each center frequency has an explicit channel number. Also, support for variables such as power class and receiver capabilities are managed by capability signaling in order to ensure that devices can adapt to each other's capabilities. The hardware will not support the full spectrum of frequency bands of the standard but will be defined by the application.


You mention audio applications.  If the customer needs site-wide communications, do we still need to install a standard DECT system or will DECT NR+ be able to carry DECT audio communication?

Site-wide communication systems available in the market today are based on the classic DECT standard. Similar systems based on DECT NR+ may be developed in the future but are not available yet. It is expected that future multi-cell DECT systems will be based on DECT NR+, as the new standard will enable many new features that have not been available to date when using classic DECT.


Before the formal availability of the Wirepas stack, can I become a beta tester or a beta user using the Nordic 9160 SIP or equivalent?

We recommend that you get in touch with the sales teams at Wirepas and Nordic Semiconductor. As a starting point before the commercial release, signing separate licenses with both Wirepas (Wirepas 5G Mesh SLA) and Nordic Semiconductor is required.


Are there any major cellular carriers currently showing any interest in supporting the DECT NR+ standard?

Carriers are not required for mass adoption as the DECT NR+ standard allows the customer to build its own private mesh network without operator infrastructure. The devices provide the radio resources, with a sink or gateway device that connects the radio mesh network to the Internet or backend systems. Where the connection technology used for backend connection is concerned, DECT NR+ is agnostic. This backend connection can, for example, be a regular cellular modem running in an operator network. Still, from the operator viewpoint, it is normal cellular communication on established technologies and radio bands. The DECT NR+ network itself is independent of a cellular provider and the DECT 1.9GHz band is reserved for DECT and DECT NR+ devices to operate in. 

Any cellular carrier can utilize this technology as a part of its connectivity and service offering.

Questions on the openness of the standard

Will DECT NR+ include any "Standard Essential Patents" that a user or implementer needs to be aware of and take care of?

DECT NR+ is an open standard based on series TS 103 636 parts 1 to 5 developed by ETSI and is covered by ETSI IPR policy, the same as any other ETSI standard. The specifications are openly available to anyone interested in building their own solution. The future development of DECT NR+ is open to any ETSI member.
The DECT Forum recommends studying IPR policy at https://etsi.org/intellectual-property-rights


Will DECT NR+ always be bound to Wirepas? Or will it be possible in the future to implement DECT NR+ without the Wirepas Stack?

The above-mentioned answer also applies here. DECT NR+ is an open standard based on series TS 103 636 parts 1 to 5 developed by ETSI. The specifications are openly available to anyone interested in building their own solution. The future development of DECT NR+ is open to any ETSI member.

You can watch the recording of the full webinar of introduction to the DECT NR+ here.
Register for our next DECT NR+ webinar on Applications here. 
If you have any questions, feel free to contact us.