osmocom-bb[fixeria/trx]: fake_trx: handle SETTA (Timing Advance) indicated by MS
Patch Set 1: Code-Review+2 -- To view, visit https://gerrit.osmocom.org/6999 To unsubscribe, visit https://gerrit.osmocom.org/settings Gerrit-MessageType: comment Gerrit-Change-Id: Ie5833a9f221587bbcac10f0b223ead9c1cbda72b Gerrit-PatchSet: 1 Gerrit-Project: osmocom-bb Gerrit-Branch: fixeria/trx Gerrit-Owner: Vadim Yanitskiy Gerrit-Reviewer: Harald Welte Gerrit-Reviewer: Jenkins Builder Gerrit-HasComments: No
[PATCH] osmocom-bb[fixeria/trx]: fake_trx: handle SETTA (Timing Advance) indicated by MS
Review at https://gerrit.osmocom.org/6999
fake_trx: handle SETTA (Timing Advance) indicated by MS
Timing Advance value is a timing correction value, indicated by
the network to MS, which is used to compensate UL signal delay.
In other words, the network instructs a phone to transmit bursts
N=TA symbol periods earlier than expected.
Since we are in virtual environment, let's use TA value to
calculate the ToA (Timing of Arrival) value for BTS.
Change-Id: Ie5833a9f221587bbcac10f0b223ead9c1cbda72b
---
M src/target/fake_trx/burst_fwd.py
M src/target/fake_trx/ctrl_if_bb.py
2 files changed, 33 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmocom-bb refs/changes/99/6999/1
diff --git a/src/target/fake_trx/burst_fwd.py b/src/target/fake_trx/burst_fwd.py
index 4a0e9bb..bcf2257 100644
--- a/src/target/fake_trx/burst_fwd.py
+++ b/src/target/fake_trx/burst_fwd.py
@@ -34,6 +34,11 @@
bts_freq = None
bb_freq = None
+ # Timing Advance value indicated by MS (0 by default)
+ # Valid range: 0..63, where each unit means
+ # one GSM symbol advance.
+ ta = 0
+
# Constants
# TODO: add options to change this
RSSI_RAND_TRESHOLD = 10
@@ -56,6 +61,17 @@
# Generate a random ToA range
self.toa256_min = self.TOA256_RAND_BASE -
self.TOA256_RAND_TRESHOLD
self.toa256_max = self.TOA256_RAND_BASE +
self.TOA256_RAND_TRESHOLD
+
+ # Calculates ToA value for Uplink bursts (coming to a BTS)
+ def calc_toa_ul(self):
+ # Generate a random ToA value
+ toa256 = random.randint(self.toa256_min, self.toa256_max)
+
+ # Apply TA value
+ ta256 = self.ta * 256
+ toa256 -= ta256
+
+ return toa256
# Converts a L12TRX message to TRX2L1 message
def transform_msg(self, msg_raw):
@@ -128,6 +144,9 @@
if msg is None:
return None
+ # Emulate ToA value for BTS
+ msg.toa256 = self.calc_toa_ul()
+
# Validate and generate the payload
payload = msg.gen_msg()
diff --git a/src/target/fake_trx/ctrl_if_bb.py
b/src/target/fake_trx/ctrl_if_bb.py
index 47c7048..74fb242 100644
--- a/src/target/fake_trx/ctrl_if_bb.py
+++ b/src/target/fake_trx/ctrl_if_bb.py
@@ -115,6 +115,20 @@
return 0
+ # Timing Advance
+ elif self.verify_cmd(request, "SETTA", 1):
+ print("[i] Recv SETTA cmd")
+
+ # Parse and check TA value
+ ta = int(request[1])
+ if ta < 0 or ta > 63:
+ print("[!] TA value should be in range: 0..63")
+ return -1
+
+ # Save to the BurstForwarder instance
+ self.burst_fwd.ta = ta
+ return 0
+
# Wrong / unknown command
else:
# We don't care about other commands,
--
To view, visit https://gerrit.osmocom.org/6999
To unsubscribe, visit https://gerrit.osmocom.org/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: Ie5833a9f221587bbcac10f0b223ead9c1cbda72b
Gerrit-PatchSet: 1
Gerrit-Project: osmocom-bb
Gerrit-Branch: fixeria/trx
Gerrit-Owner: Vadim Yanitskiy
[MERGED] osmocom-bb[fixeria/trx]: fake_trx: handle SETTA (Timing Advance) indicated by MS
Harald Welte has submitted this change and it was merged.
Change subject: fake_trx: handle SETTA (Timing Advance) indicated by MS
..
fake_trx: handle SETTA (Timing Advance) indicated by MS
Timing Advance value is a timing correction value, indicated by
the network to MS, which is used to compensate UL signal delay.
In other words, the network instructs a phone to transmit bursts
N=TA symbol periods earlier than expected.
Since we are in virtual environment, let's use TA value to
calculate the ToA (Timing of Arrival) value for BTS.
Change-Id: Ie5833a9f221587bbcac10f0b223ead9c1cbda72b
---
M src/target/fake_trx/burst_fwd.py
M src/target/fake_trx/ctrl_if_bb.py
2 files changed, 33 insertions(+), 0 deletions(-)
Approvals:
Harald Welte: Looks good to me, approved
Jenkins Builder: Verified
diff --git a/src/target/fake_trx/burst_fwd.py b/src/target/fake_trx/burst_fwd.py
index 4a0e9bb..bcf2257 100644
--- a/src/target/fake_trx/burst_fwd.py
+++ b/src/target/fake_trx/burst_fwd.py
@@ -34,6 +34,11 @@
bts_freq = None
bb_freq = None
+ # Timing Advance value indicated by MS (0 by default)
+ # Valid range: 0..63, where each unit means
+ # one GSM symbol advance.
+ ta = 0
+
# Constants
# TODO: add options to change this
RSSI_RAND_TRESHOLD = 10
@@ -56,6 +61,17 @@
# Generate a random ToA range
self.toa256_min = self.TOA256_RAND_BASE -
self.TOA256_RAND_TRESHOLD
self.toa256_max = self.TOA256_RAND_BASE +
self.TOA256_RAND_TRESHOLD
+
+ # Calculates ToA value for Uplink bursts (coming to a BTS)
+ def calc_toa_ul(self):
+ # Generate a random ToA value
+ toa256 = random.randint(self.toa256_min, self.toa256_max)
+
+ # Apply TA value
+ ta256 = self.ta * 256
+ toa256 -= ta256
+
+ return toa256
# Converts a L12TRX message to TRX2L1 message
def transform_msg(self, msg_raw):
@@ -128,6 +144,9 @@
if msg is None:
return None
+ # Emulate ToA value for BTS
+ msg.toa256 = self.calc_toa_ul()
+
# Validate and generate the payload
payload = msg.gen_msg()
diff --git a/src/target/fake_trx/ctrl_if_bb.py
b/src/target/fake_trx/ctrl_if_bb.py
index 47c7048..74fb242 100644
--- a/src/target/fake_trx/ctrl_if_bb.py
+++ b/src/target/fake_trx/ctrl_if_bb.py
@@ -115,6 +115,20 @@
return 0
+ # Timing Advance
+ elif self.verify_cmd(request, "SETTA", 1):
+ print("[i] Recv SETTA cmd")
+
+ # Parse and check TA value
+ ta = int(request[1])
+ if ta < 0 or ta > 63:
+ print("[!] TA value should be in range: 0..63")
+ return -1
+
+ # Save to the BurstForwarder instance
+ self.burst_fwd.ta = ta
+ return 0
+
# Wrong / unknown command
else:
# We don't care about other commands,
--
To view, visit https://gerrit.osmocom.org/6999
To unsubscribe, visit https://gerrit.osmocom.org/settings
Gerrit-MessageType: merged
Gerrit-Change-Id: Ie5833a9f221587bbcac10f0b223ead9c1cbda72b
Gerrit-PatchSet: 1
Gerrit-Project: osmocom-bb
Gerrit-Branch: fixeria/trx
Gerrit-Owner: Vadim Yanitskiy
Gerrit-Reviewer: Harald Welte
Gerrit-Reviewer: Jenkins Builder
