diff options
authorPau Espin Pedrol <pespin@sysmocom.de>2018-09-19 17:43:09 +0200
committerPau Espin Pedrol <pespin@sysmocom.de>2018-09-19 17:43:09 +0200
commit72e569f784c78d8a1c28fdc090cf815843279016 (patch)
parent0381f5a1692af1d1e14b1a828ca62db0b5c9d191 (diff)
osmotrx: configuration: Add section to document multi-arfcn feature
1 files changed, 49 insertions, 0 deletions
diff --git a/OsmoTRX/chapters/configuration.adoc b/OsmoTRX/chapters/configuration.adoc
index cdde366..87d7903 100644
--- a/OsmoTRX/chapters/configuration.adoc
+++ b/OsmoTRX/chapters/configuration.adoc
@@ -34,3 +34,52 @@ trx
<7> Configure the first channel. As no other channels are specified, `osmo-trx` assumes it is using only one channel.
<8> Configure the device to use `BAND1` Tx antenna path from all the available ones (device specific).
<9> Configure the device to use `LNAW` Rx antenna path from all the available ones (device specific).
+=== Multi-ARFCN mode
+The Multi-ARFCN feature allows to have a multi-carrier approach multiplexed on a
+single physical RF channel, which can introduce several benefits, such as lower
+cost and higher capacity support.
+Multi-ARFCN support is available since osmo-trx release `0.2.0`, and it was
+added specifically in commit `76764278169d252980853251daeb9f1ba0c246e1`.
+This feature is useful for instance if you want to run more than 1 TRX with an
+Ettus B200 device, or 3 TRX with an Ettus B210 device, since they support only 1
+and 2 physical RF channels respectively. No device from other providers or even
+other devices than B200 and B210 from Ettus are known to support this feature.
+With multi-ARFCN enabled, ARFCN spacing is fixed at 800 kHz or 4 GSM channels.
+So if TRX-0 is set to ARFCN 51, TRX-1 _must_ be set to 55, and so on. Up to
+three ARFCN's is supported for multi-TRX.
+From BTS and BSC point of view, supporting multiple TRX through multi-ARFCN
+feature in OsmoTRX doesn't make any difference from a regular multi-TRX setup,
+leaving apart of course the mentioned ARFCN limitations explained above and as a
+consequence physical installation and operational differences.
+.Example: osmo-bts-trx.cfg using 2 TRX against an osmo-trx driven device
+phy 0
+ osmotrx ip local
+ osmotrx ip remote
+ instance 0
+ instance 1
+bts 0
+ ...
+ band GSM-1800
+ trx 0
+ phy 0 instance 0
+ trx 1
+ phy 0 instance 1
+.Example: osmo-trx.cfg using Multi-ARFCN mode to run 2 TRX
+ ...
+ multi-arfcn enable
+ chan 0
+ chan 1