DECT NR+ power class and bandwidth/data rate

RE: DECT NR+ power class and bandwidth/data rate

Zach Williams — Tue, 19 May 2026 15:02:21 GMT

dejans you mentioned above "Due to this firmware limitation, maximum achievable rate is 2.4 Mbps."

Has this changed with the v2.0.0 PHY firmware?

RE: DECT NR+ power class and bandwidth/data rate

dejans — Thu, 08 May 2025 07:45:26 GMT

Hi,

Two slots is just the default in perf command. It is possible to change this and assign custom value using --c_gap_slots <int> which counts gap slots between operations. Default value is 2. It is also possible to go to subslot accuracy by using --c_gap_subslots <int> which instead of slots, counts gap subslots between operations. More information can be obtained from help using command dect perf -h.

Best regards,
Dejan

RE: DECT NR+ power class and bandwidth/data rate

Isitha — Mon, 05 May 2025 14:55:39 GMT

Hi Dejans,

Thanks for the detailed explanation, very helpful.

I just have a follow-up question regarding the limitation you mentioned.

I noticed that using the perf shell command introduces a fixed ~820 µs gap between consecutive transmissions. In contrast, when I manually schedule back-to-back TXs using start_time = 0, the gap drops to ~430 µs, which matches the modem’s idle_to_tx latency.

From the source code "dect_phy_perf.c", it seems this additional delay is enforced via slot_gap_count = 2 (i.e., 2 × 416 µs), even when HARQ is disabled.

Could you please confirm if there is a specific reason for this added gap? Is it related to internal modem constraints, reliability, or just for clarity in test profiling?

Best regards,

RE: DECT NR+ power class and bandwidth/data rate

dejans — Tue, 21 Jan 2025 12:08:58 GMT

Hi,

I am sorry for a delayed reply.

[quote user=""]I see that from the docs that the max TX power is 19dBm, so it's a Class III device as defined in section 6.2.1 of TS 103 636-2. Is this a hardware limitation, or a a software one due to regulatory compliance or something?[/quote]

Max Tx power of 19 dBm is a current hardware limitation.

[quote user=""]The docs mention that data rate is up 3.4Mbps. However, the closest value I found in TS 103 636-2 was Table A.4.2-3, which uses the operating bandwidth of 6.912MHz. The docs say the max operating bandwidth of the chip itself is 1.728MHz. Does that mean the docs talk about the capabilities of the DECT NR+ PHY and not the chip in terms of bitrate?[/quote]

Maximum theoretical peak data rate is 3.4 Mbps when transmission is scheduled into packets of 4 slots using MCS4, and these 4 slot packets are transmitted back-to-back. In this case, each of the physical layer packets carries 5600 bits which gives the rate of 5600bits / (4*416 us) =3,36Mbit/s. However, there is currently a limitation of scheduling packets back-to-back. Due to this firmware limitation, maximum achievable rate is 2.4 Mbps. Maximum peak data rates with 4 slot packets are 0.552, 1.118, 1.646, 2.222 and 3.360 Mbit/s for MCS0, 1, 2, 3 and 4, respectively.

Best regards,
Dejan

RE: DECT NR+ power class and bandwidth/data rate

Mark Szente — Mon, 13 Jan 2025 16:29:16 GMT

Thanks!

RE: DECT NR+ power class and bandwidth/data rate

dejans — Mon, 13 Jan 2025 16:20:38 GMT

Hi,

I will check this internally and get back to you by the end of this week.

Best regards,
Dejan