Underruns are only explicitly set on the downlink side. Overruns
are logged but unused. In either case, reset indicators to false
to avoid sending false state information.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6817 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Use the same measurement method for RSSI as the noise level. Previous
method was to use the peak correlation amplitude relative to the
expected value. This created two very different amplitude approaches
between the noise measurement and RSSI measurement, which would
throw off the upper layer MS power control loop.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6761 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Previous removal of the energy detector requirement broke
the noise level calculation loop. The previous adaptive
approach was finicky - noticably at high gain levels. Since
we no longer use the energy threshold for primary burst gating,
we can return to a simpler world.
In the new approach, we compute a running average of energy
levels and track them with a noise vector. A timeslot that
passes the correlator threshold is a valid burst. These are
not used in the noise calculation. Everything else is
considered noise and used to compute the noise level with
respect to full scale input level, which for almost all
supported devices is 2^15.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6755 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Enabling the external reference on UHD devices through the configure
time switch is awkward. Use a database variable "TRX.Reference" with
'0' or '1' value for internal and external references respectively.
Use internal reference is no entry is defined.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6754 19bc5d8c-e614-43d4-8b26-e1612bc8e597
We want to push UHD logs to the OpenBTS logging system, but most
device errors occur at startup, so keep the output on stdout until
after device initialization. That way obvious errors are easily
viewable before seeing the useless TRX timeout message.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6753 19bc5d8c-e614-43d4-8b26-e1612bc8e597
This primarily addresses the error case at initialization.
In the event that the transceiver fails to start, we should
be able cleanly shutdown and release while providing a useful
reason for exiting.
After the radio is started and threads launched, there
are no thread state variables or shutdown messaging between
threads, and the transceiver cannot be consistently
shutdown. This issue remains to be solved.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6752 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Previous send and receive buffers at the radio interface were
arbitrarily set to a sufficient size. For normal (non-resampling)
devices, use a block (chunk) size of 625 samples. For 64 or 100
MHz resampling devices, use 4 times the reduced resampling
numerator or denominator and provide bounds checking where
appropriate.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6751 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Move B100 to the resampling interface with default
clocking. This temporarily resolves undetermined
FPGA clocking issues. This also provides extensible
support for multiple clocking rates and resampling
ratios.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6750 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Current functionality with these old versions is questionable.
There is no reason to use any version of GNU Radio / libusrp older
than 3.3. Version 3.4.2 is the only recommended version for USRP1
users.
Non-USRP1 users must use UHD driver from Ettus Research.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6749 19bc5d8c-e614-43d4-8b26-e1612bc8e597
This patch applies oversampling, when selected with 4 sps,
to the downlink only, while running the receiver with
minimal sampling at 1 sps. These split sample rates allow
us to run a highly accurate downlink signal with minimal
distortion, while keeping receive path channel filtering
on the FPGA.
Without this patch, we oversample the receive path and
require a steep receive filter to get similar adjacent
channel suppression as the FPGA halfband / CIC filter
combination, which comes with a high computational cost.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6747 19bc5d8c-e614-43d4-8b26-e1612bc8e597
This requires an additional memcpy() on the signal vector
constructor, but allows the interpolation filter to use
SSE optimzationed convolution.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6746 19bc5d8c-e614-43d4-8b26-e1612bc8e597
This patch primarily addresses observed repeated overrun
conditions in embedded environments - namely ARM.
The heartbeat of the transceiver is derived from the receive
sample stream, which drives the main GSM clock. Detach the
transmit thread from the receive loop to avoid interfering with
the receive I/O, which is sensitive to overrun conditions if
pull process is interrupted.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6745 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Start the correlation search window at 4 symbols before
the expected correlation peak. End the search at 10
symbols and 4 + maximum expected delay for RACH and TSC
bursts respectively.
This change lowers receive side cpu utilization while
maintaining reasonable timing jitter and accuracy tolerance.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6743 19bc5d8c-e614-43d4-8b26-e1612bc8e597
This patch only applies to resampling use at 4 samples-per-symbol.
By extention that means only USRP2 / N2xx devices are affected.
At 4 samples-per-symbol we restrict output bandwidth to roughly
roughly 700 MHz, which combined with the 2 pulse Laurent
approximation yields < 0.5 degrees of RMS phase error at the
resampler output.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6742 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Set master clock rate to 52 MHz for B200. Also, we want to avoid
floating point comparison errors on clock rate settings, but we
expect to be able really set the rates we specify. Set the
offset limit to 1 Hz. If we can't set our rates with that level
of precision, then something is wrong.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6741 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Provides substantially improved transmit phase error
performance when enabled. Requires use of 4 samples
per symbol, and is enabled by default when set.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6740 19bc5d8c-e614-43d4-8b26-e1612bc8e597
If there is an error in the sample rate determination, noted
by a negative return sample rate value, error directly and
don't try to set the device rate.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6739 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Both RACH and normal bursts are detected with the same approach of
midamble correlation combined with peak-to-average ratio. The
difference is the midamble placements and lengths. Thus, there is
no reason to have independent implementations.
This patch creates a common call burstDetect(), while leaving the
correlation window indexing in the original calls.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6738 19bc5d8c-e614-43d4-8b26-e1612bc8e597
When 4 samples-per-symbol operation is selected, replace the
existing pulse approximation, which becomes inaccurate with
non-unit oversampling, with the primary pulse, C0, from the
Laurent linear pulse approximation.
Pierre Laurent, "Exact and Approximate Construction of Digital Phase
Modulations by Superposition of Amplitude Modulated Pulses", IEEE
Transactions of Communications, Vol. 34, No. 2, Feb 1986.
Octave pulse generation code for the first three pulses of the
linear approximation are included.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6736 19bc5d8c-e614-43d4-8b26-e1612bc8e597
The adaptive energy threshold gating suffers a near-far problem
at certain gain levels. This is due to exponential threshold
raising, but linear decreases. A large signal level followed by
a period low signal level causes (comparatively) weak signals to
go undetected. Additionally, the algorithm performs differently
at multiple RF gain levels.
This patch switches solely to correlation based gating for burst
detection. The main computational load with this approach is
sub-sample width peak interpolation, which we disable for intial
detection and run after threshold passing.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6735 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Replace the polyphase filter and resampler with a separate
implementation using SSE enabled convolution. The USRP2 (including
derived devices N200, N210) are the only supported devices that
require sample rate conversion, so set the default resampling
parameters for the 100 MHz FPGA clock. This changes the previous
resampling ratios.
270.833 kHz -> 400 kHz (65 / 96)
270.833 kHz -> 390.625 kHz (52 / 75)
The new resampling factor uses a USRP resampling factor of 256
instead of 250. On the device, this allows two halfband filters to
be used rather than one. The end result is reduced distortial and
aliasing effecits from CIC filter rolloff.
B100 and USRP1 will no be supported at 400 ksps with these changes.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6733 19bc5d8c-e614-43d4-8b26-e1612bc8e597
This large patch replaced the convolve() call with an SSE vector
enabled version. The lower C and SSE intrinsic based code operates
on fixed and aligned vectors for the filter taps. The storage format
of interleaved I/Q for both complex and real vectors is maintained.
SSE filter tap values must:
1. Start 16-byte aligned
2. Number with a multiple of 4 between 4 and 20 for real taps
3. Number with a multiple of 4 for complex taps
Non-compliant values will fall back to non-SSE usage. Fixed length
iterators mean that head and tail cases may require reallocation of
the input vector, which is automatically handled by the upper C++
interface.
Other calls are affected by these changes and adjusted or rewritten
accordingly. The underlying algorithms, however, are unchanged.
generateGSMPulse()
analyzeTrafficBurst()
detectRACHBurst()
Intel SSE configuration is automatically detected and configured at
build time with Autoconf macros.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6732 19bc5d8c-e614-43d4-8b26-e1612bc8e597
There is no temporal dependency on when the RACH sequence is generated,
so there is no need for transceiver to create it in response to a
command from GSM core. If we power on the transceiver, we will need
the RACH sequence, so just allocate it during initialization.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6731 19bc5d8c-e614-43d4-8b26-e1612bc8e597
The only logging outputs in the the signal processing library
are debug lines that generate copious amounts of output while
providing little useful information to the user. The relevant
information (time-of-arrival, channel gains, etc.) can and
should be logged from transceiver instance itself.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6730 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Add destructor calls so we can avoid the nested vector deallocations.
Also remove the unnecessary pointer NULL checks prior to destruction.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6729 19bc5d8c-e614-43d4-8b26-e1612bc8e597
There is no reason expose the pulse shaping filter outside of the
signal processing calls. The main transceiver object makes no use
of the filter and there's no reason to pass it around.
Initialize the pulse shape with the signal processing library, and
maintain an internal static member like many of the other library
variables. Similarly destroy the object when the library is closed.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6728 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Because repeatedly typing mSamplesPerSymbol is giving me
carpal tunnel syndrome. Replace with the much shorter,
easier to type, and just as clear name of 'sps'.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6727 19bc5d8c-e614-43d4-8b26-e1612bc8e597
The configuration table is instantiated as a global variable with
no means to check constructor status. This means various types
of database failure conditions (e.g. file existence, permissions,
etc.) are not reported. This patch performs a small number of
checks to make sure that the configuration is sane.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6726 19bc5d8c-e614-43d4-8b26-e1612bc8e597
UHD will throw if something goes awry in these sensitive sections,
so we should catch and shutdown gracefully. There is no recovery
if we can't set rates.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6724 19bc5d8c-e614-43d4-8b26-e1612bc8e597
