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Support #4505

LimeSDR+osmo-bts-trx+gsm-r band set

Added by dingdingYang 3 months ago. Updated 2 months ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
-
Target version:
-
Start date:
04/19/2020
Due date:
% Done:

0%

Spec Reference:

Description

I'm using LimeSDR based osmo-bts-trx.And I want to support GSM-R frequency band by them.
I have read the description documents,but not found the GSM-R band config in osmo-bts-trx.So I have two questions about this:
1.Does osmo-bts-trx support GSM-R frequency band?
2.If osmo-bts-trx support GSM-R frequency,what should I do to set band config?

History

#1 Updated by fixeria 3 months ago

1.Does osmo-bts-trx support GSM-R frequency band?

If you check the actual band/frequency mapping [1], you will see that it uses the same frequencies as E-GSM. Thus no 'special' band configuration is required.

[1] https://en.wikipedia.org/wiki/Absolute_radio-frequency_channel_number#ARFCN_table_for_common_GSM_systems

#2 Updated by laforge 2 months ago

Just to be clear here: Even if you get the SDR to transmit on an GSM-R ARFCN,
this by far doesn't make the Osmocom stack implement GSM-R. The different
frequency is only one of the many differences between GSM and GSM-R.

One would have to add at least the following features:
  • ASCI (VBS, VGCS) including the NCH on Um, and related signaling on Abis and A
  • CSD on the control plane as well as the user plane (Um, Abis/RTP, MGCP, MGW, ...)

#3 Updated by laforge 2 months ago

fixeria wrote:

If you check the actual band/frequency mapping [1], you will see that it uses the same frequencies as E-GSM.

This is not correct. GSM-R uses frequencies below E-GSM. This is why GSM-R
handsets have special band filters that are different than normal band filters.

#4 Updated by fixeria 2 months ago

This is not correct. GSM-R uses frequencies below E-GSM...

Oh, you're right. Sorry for confusion. The Ful(x) formula is the same, but ARFCN ranges are different...

#5 Updated by dingdingYang 2 months ago

laforge wrote:

fixeria wrote:

If you check the actual band/frequency mapping [1], you will see that it uses the same frequencies as E-GSM.

This is not correct. GSM-R uses frequencies below E-GSM. This is why GSM-R
handsets have special band filters that are different than normal band filters.

Thank you very much,谢谢

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