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fixeria gerrit-no-reply at lists.osmocom.orgfixeria has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-gsm-manuals/+/22620 ) Change subject: TRXD: describe general message format, reduce duplication ...................................................................... TRXD: describe general message format, reduce duplication Change-Id: If3bd16fdf5abfd67b3822c7199003d6f7cbaff92 Related: SYS#4895, OS#4941, OS#4006 --- M common/chapters/trx_if.adoc 1 file changed, 44 insertions(+), 27 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-gsm-manuals refs/changes/20/22620/1 diff --git a/common/chapters/trx_if.adoc b/common/chapters/trx_if.adoc index c86e75e..703904f 100644 --- a/common/chapters/trx_if.adoc +++ b/common/chapters/trx_if.adoc @@ -341,7 +341,50 @@ === TRXD protocol -Messages on the data interface carry one radio burst per UDP message. +Messages on the data interface carry one radio burst per UDP message. Two +kinds of such messages exist: + +* `TRX -> L1` (from transceiver to the L1): Uplink messages received from the MS, +* `L1 -> TRX` (from the L1 to transceiver): Downlink messages sent to the MS. + +Regardless of the origin, all PDUs have the following common structure: + +.General message format +[packetdiag] +---- +{ + colwidth = 32 + node_height = 40 + + 0-3: VER + 4: RFU [rotate = 270] + 5-7: TN + 8-63: ... Specific fields ... + 64-95: Burst bits [colheight = 3] +} +---- + +VER: 4 bits:: +TRXD header version, common for both `TRX -> L1` and `L1 -> TRX` directions. + +TN: 3 bits:: +TDMA timeslot number. + +RFU: 1 bit:: +Reserved, shall be 0. It can be used in the future to extend the TDMA TN range +to (0..15), in case anybody would need to transfer UMTS bursts. + +FN: 32 bits (4 bytes):: +TDMA frame number, big endian. + +Specific fields: variable length:: +This part depends on the origin of a message and the header version. See below. + +Burst bits: variable length:: +The actual bit sequence of a burst, where each bit takes one octet. Depending on +the origin, all bits in the sequence are either _soft-bits_ (from demodulator) or +_hard-bits_ (to the modulator). Length of the sequence depends on modulation +type of the burst. ==== Uplink Data Burst @@ -404,19 +447,6 @@ } ---- -VER: 4 bits:: -TRXD header version, v0 and v1 are specified so far. - -TN: 3 bits:: -Timeslot number. - -RES: 1 bit:: -Reserved, shall be 0. It can be used in the future to extend the TDMA TN range -to (0..15), in case anybody would need to transfer UMTS bursts. - -FN: 32 bits (4 bytes):: -GSM frame number, big endian. - RSSI: 8 bits (1 byte):: Received Signal Strength Indication in -dBm, encoded without the negative sign. @@ -529,19 +559,6 @@ } ---- -VER: 4 bits:: -TRXD header version, v0 and v1 are specified so far. - -TN: 3 bits:: -Timeslot number. - -RES: 1 bit:: -Reserved, shall be 0. It can be used in the future to extend the TDMA TN range -to (0..15), in case anybody would need to transfer UMTS bursts. - -FN: 32 bits (4 bytes):: -GSM frame number, big endian. - PWR: 8 bits (1 byte):: Contains the relative (to the full-scale amplitude) transmit power *reduction* in dB. The absolute value is set on the control interface, so the resulting -- To view, visit https://gerrit.osmocom.org/c/osmo-gsm-manuals/+/22620 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-gsm-manuals Gerrit-Branch: master Gerrit-Change-Id: If3bd16fdf5abfd67b3822c7199003d6f7cbaff92 Gerrit-Change-Number: 22620 Gerrit-PatchSet: 1 Gerrit-Owner: fixeria <vyanitskiy at sysmocom.de> Gerrit-MessageType: newchange -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.osmocom.org/pipermail/gerrit-log/attachments/20210201/a31e3cf5/attachment.htm>