DECT NR+ (ETSI DECT-2020 NR, TS 103 636) is a licence-exempt 5G standard for decentralised mesh — no base station, no operator, no SIM. FLSEMI writes its own MAC stack for it. This page is about how that stack is built and what we do to it before we believe it: clause by clause from the specification, verified against the test specification, and then made to survive conditions we create on purpose.
Each pass through the loop closes one clause of the specification and opens the next. Nothing is declared finished; it is declared converged for now, and revisited when the layer above it changes what the layer below has to survive.
TS 103 636 is taken apart clause by clause. Each clause becomes a discrete implementation unit with its own definition of done, rather than a feature bullet on a roadmap.
Every unit is exercised against the corresponding test specification before anything is built on top of it. A clause that has not been measured is not a foundation.
We stand up our own interference sources, CW generators and passive monitors, then run the implementation into conditions that a clean bench would never produce.
Packet-level observation drives the behaviour toward a stable model. When it settles, the next layer goes on — and the whole stack is read again from the top.
The loop runs per clause. When a layer converges, the next one goes on top — and the completed stack is read again from the beginning, because a new layer changes what the layers beneath it have to tolerate.
A link cannot be judged from one endpoint. The bench runs a device under test, a reference peer, an interference source and a passive monitor at the same time — physically separated across the room rather than stacked on one desk, so distance and obstruction are part of the test rather than absent from it.
The position a product occupies. During our own development it holds the implementation being changed; when we bring up a customer's module, board or integration, this is where it sits and what the rest of the bench is pointed at. Its RF path is brought out to external connectors with calibrated in-line attenuation, so path loss is a set value rather than a consequence of where the board happens to be lying.
The known-good counterpart that closes the link, running an integrated antenna rather than external connectors — because that is what a finished product actually radiates. Holding one end fixed and known is what makes a change at the other end attributable.
Adversaries we build on purpose: a packet-level interferer that contends for the channel, and a continuous-wave source that raises the noise floor without any protocol behaviour at all. Between them they separate “the stack mishandled contention” from “the link simply ran out of margin”.
An observer that captures the air interface without joining it, so nothing we learn is an artefact of the measurement participating in the link. It is never the same unit as the interferer — what breaks the link and what records it stay independent.
The DUT position is the one that changes. Everything else on the bench exists to make what happens there attributable — which is why the same topology serves a customer bringing up their own DECT NR+ device as well as it serves our own stack development.
The stack is built from the bottom. Each layer is only started once the one beneath it holds under adversarial conditions — and adding it sends us back through everything below.
The first layer to converge and the one that everything else inherits. Access, scheduling and the behaviour of the link when the channel is contested are settled here before anything is layered on.
Added only once MAC behaviour is stable under injected interference. Its arrival changes the traffic the MAC sees, which is why the MAC is re-measured rather than assumed.
The layer that faces the application. By the time it goes on, the two layers beneath it have each been observed at packet level under conditions we generated deliberately.
With all three layers in place the whole implementation is read back against the specification from the beginning — not as a formality, but because the completed stack is a different system from the sum of its converged layers.
Everything on this page describes how we develop and verify our own implementation. FLSEMI's DECT NR+ stack is written to ETSI TS 103 636 Release 2 and has been exercised against the corresponding test specification on our own bench. It has not been submitted for formal conformance testing, and nothing here is a claim of protocol conformance or of regulatory approval.
The service description on this page sets out how we normally work. It is not an offer and does not form a contract. Scope, price, payment stages and schedule are established in the written quotation and the signed agreement for each engagement.
The same bench and the same method are available as a paid engagement — your device takes the DUT position instead of ours.
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