[HN Gopher] DECT NR+: A technical dive into non-cellular 5G
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DECT NR+: A technical dive into non-cellular 5G
Author : teleforce
Score : 61 points
Date : 2024-04-02 13:40 UTC (9 hours ago)
(HTM) web link (devzone.nordicsemi.com)
(TXT) w3m dump (devzone.nordicsemi.com)
| throw0101b wrote:
| From a few days ago, "What is DECT-2020 New Radio (NR), and how
| big a deal is it?":
|
| * https://news.ycombinator.com/item?id=39849335
| martinky24 wrote:
| Same OP, same linked domain. Interesting. This blog post is
| significantly more thorough than the last one they posted.
| p_l wrote:
| Nordic Semi is a vendor in this space - many hardware vendors
| will make similar posts on different levels of technical
| depth in order to both drum up interest and build awareness
| of their products.
|
| Note that the article has links to two modem chips that
| handle IIoT 5G radio links, including DECT NR+, that are made
| by Nordic Semi.
|
| Content marketing at its best.
| jschveibinz wrote:
| This can be a game-changer for certain low bandwidth unlicensed
| applications where the ongoing cost of cellular or satellite
| service makes the application economically infeasible. I could
| envision a whole layer of startup opportunities based on this
| technology from commercial applications like pets, construction,
| fleet management, security, and agriculture to a gazillion
| defense and intel applications. If I were younger, I would
| definitely dig into this further and compare it to LoRA and other
| existing radio technologies. Cheers!
| thijson wrote:
| This seems to be an order of magnitude better than LoRa
| (https://lora-alliance.org/ not
| https://arxiv.org/abs/2106.09685). LoRa doesn't have all the
| features this one does like OFDM, TDM, FDM, and HARQ. I didn't
| know there's spectrum dedicated for DECT use.
| ianburrell wrote:
| DECT-NR competition is 802.11ah and BLE Long Range. They all
| provide moderate bandwidth and moderate range, up to 1-2km. I
| bet they aren't low enough for battery-powered sensors, but
| probably good for battery-powered devices like Wifi or LTE.
|
| My guess is that winner will be whoever get cheap devices
| out, and leverages their ecosystem.
| londons_explore wrote:
| Why limit mesh topologies to cluster-trees? There are plenty of
| more efficient ways to route data...
|
| I'd design it having message flooding for peer discovery (no hop
| limit, but a bandwidth limit - never use more than 0.1% of the
| total throughput for flooded messages).
|
| Then, once connections are established, pick a few best routes,
| and send some proportion of data down each. Weight the paths via
| a cost function that takes into account load of each node, power
| use/availability of each node, impact of each flow on other flows
| (prefer getting nodes to transmit who cause least interference to
| other flows), etc.
|
| Over time, adjust proportions of data down different routes to
| minimize the cost function.
| londons_explore wrote:
| Smart move calling what is effectively an entirely new standard
| "DECT" to get free use of DECT's old frequency bands that are
| barely used by their original use for cordless phones anymore...
| gruez wrote:
| The bands themselves are unlicensed; anyone can use them. You
| don't have to be specifically called "DECT" to use them.
| londons_explore wrote:
| You do in some countries...
| zettabomb wrote:
| What countries require licensing for ISM bands?
| b3orn wrote:
| DECT uses 1880-1900 MHz in Europe, other countries use
| similar frequencies, that's not an ISM band.
| _trampeltier wrote:
| DECT is still used a lot in factorys even today. It's way
| faster to type a short number, usually between 100 .. 999. The
| often used contacts you know anyway and you don't have to
| search in contacts. If the phone drops, nobody does care. DECT
| phones on work are great.
|
| Ask HN: Why no mobile phone can also be used as a DECT phone?
| https://news.ycombinator.com/item?id=20909535
| londons_explore wrote:
| Is this an unauthenticated mesh? Ie. might my neighbours device
| be forwarding data for my device and vice versa?
| londons_explore wrote:
| I want to see _more_ unauthenticated mesh protocols.
|
| By allowing 'unauthenticated' meshing, the total radio
| throughput in a typical urban environment is dramatically
| increased. By 2x or more often. Typical packets will take more
| hops at much reduced transmit powers each time.
|
| The main reason not to do so is "what if my neighbour has
| crappy devices and black holes all my packets".
|
| But your neighbour can _already_ jam the whole spectrum and
| block all your packets. We design devices to meet
| specifications for a reason - and if the spec says "you must
| forward all packets according to this spec", and you mod your
| device to blackhole your neighbours packets, then the FCC will
| consider that jamming and treat it the same.
| dmd wrote:
| > FCC will consider that jamming and treat it the same
|
| So... they'll do nothing?
| londons_explore wrote:
| yes.
|
| But companies will be scared into only releasing devices
| that meet the spec if there is a decent risk that non-spec
| compliance leads to the whole company having their imports
| blocked.
|
| Besides, forwarding packets for another wifi user will
| likely all be handled in the wifi chipset, so there will
| probably only be ~10 implementations by the ~10 companies
| worldwide who design wifi silicon. And if you're splashing
| out tens of millions of dollars on a wifi silicon design,
| you probably are going to make some effort to getting it
| sufficiently spec compliant to not be banned.
| Animats wrote:
| Who administers the network? How is it monitored? This has the
| complexity of a small cellular network.
| sargun wrote:
| Does there exist DECT NR+ equipment yet? I imagine you can use
| the same RANs for this as "5G", but those are ridiculously
| expensive. What about mobile devices?
| aidenn0 wrote:
| TFA mentions this[1], but it's not IoT cheap.
|
| 1: https://www.mouser.com/ProductDetail/Nordic-
| Semiconductor/NR...
| p_l wrote:
| Not that expensive for the space it's used in.
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