We can't rely on an assumption that if we can't decode a burst - it's noise.
There are many rasons why we can't decode a burst even if it's well above the
noise level. Just one example is a RACH burst which can be overlapped with
another RACH burst up to a level both are completely unrecognizable. Another
example is when a burst is destroyed by bad multi-path.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
It does more harm than good. the current noise calculation is too error
prone, so we can't trust it. And we end up loosing perfectly good bursts
because of that.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
There are two primary changes in this commit:
1) Return values of detect functions changed form bool to int to actually pass
the return value from the inner function and notify higher levels about clipping.
Previously the information was lost due to conversion to bool.
2) Clipping level is not the final verdict now. We still try to demod a burst
and mark it as clipped only if the level is above the clipping level AND we can't
demod it. The reasoning for this is that in real life we want to do as much as
possible to demod the burst, because we want to get as much from our dynamic
range as possible. So a little bit of clipping is fine and is expected. We just
don't want too much of it to break our demod.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
R&S CMD57 complains about the start phase of bursts, particularly it shows
-15 to -30 deg of error for the bit 0.5 position (start tail bit). This patch
makes it happy. ETSI TS 145 004 section 2.2 describes this: "Before the first
bit of the bursts as defined in 3GPP TS 45.002 enters the modulator,
the modulator has an internal state as if a modulating bit stream consisting
of consecutive ones (di = 1) had entered the differential encoder."
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
Receive thread receives data from the device, which is a more stable source of
clocking than the transmit side. If transmit side has a hiccup, osmo-trx doesn't
send the clock indication, and transmit side is getting completely lost in time.
With this patch we ensure that clock indication keeps coming.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
Filler types was of "bool" type, which prevented it from taking values greter
than 1. And RAND filler type has integer value of 2, which was casted to 1 on
assigning, which led to a normal filler table being used instead of the RAND
one.
Previous behaviour used UHD command line args string for device search,
but did not apply the values to the device constructor. Now use the user
passed args string for both find and device construction.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
New UHD versions support split configuration of Tx gain stages.
We utilize this to set the gain configuration, optimal for
the Tx signal quality. From our measurements, VGA1 must be
18dB plus-minus one and VGA2 is the best when 23dB or lower.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
Alert user of overdriven burst input indicated by a positive
threshold detector result. This indication serves as notification
that the receive RF gain level is too high for the configured
transceiver setup.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
Non-zero buffer indices may lead to uplink/downlink timing offset
during repeated start/stop cycles. Mainly affects USRP2 and other
resampled devices that rely on the buffer to absorb sample block
sizes that are not multiples of the burst size.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
Commit 8e17df7374 "Add option for baseband frequency offset",
modified the base device API to allow for RF tuning, which was never
updated for the USRP1.
Update the implementation to match the API, however, note actual offset
in the USRP1 remains unsupported.
Signed-off-by: Tom Tsou <tom@tsou.cc>
Frequency tuning is a multi-step process with RF and DDC/DUC protoimns
that can be corrupted if both channels attempt to tune at the same time.
Signed-off-by: Tom Tsou <tom@tsou.cc>
Treat X300 similar to N200 and resample with 100 MHz base clocking,
which provides some amount of oversampling for reduced phase error
compared to the 1 sample per symbol receiver. Treat E310 similar to 13
MHz rate devices for the lowest computational use.
Signed-off-by: Tom Tsou <tom@tsou.cc>
Add stop and restart capability through the POWEROFF and POWERON
commands. Calling stop causes receive streaming to cease, and I/O
threads to shutdown leaving only the control handling thread running.
Upon receiving a POWERON command, I/O threads and device streaming are
restarted.
Proper shutdown of the transceiver is now initiated by the destructor,
which calls the stop command internally to wind down and deallocate
threads.
Signed-off-by: Tom Tsou <tom@tsou.cc>
Existing implementation outputs sample buffer parameters, but it is
helpful to know the submitted timestamp that led to the errant
condition.
Signed-off-by: Tom Tsou <tom@tsou.cc>
An errant shuffle register value used in complex-complex convolution
causes distorted correlation peak-to-average values for certain TSC
values. The error effect varies for different TSC sequences with the
most noticeable effect of degraded detection on TSC 1 and no effect on
TSC 7.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Commit 15d743efaf "Disable filler table
retransmissions by default" made OpenBTS style filler table behavior
optional. When enabled, dummy bursts were automatically loaded into the
filler table, but the table was not updated and only filler busts were
retransmitted.
Enable the restransmit state flag when the filler table option is
specified. Only preload filler table and enable retransmissions on
channel zero.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Device specific timing settings for the E100 and E110 were missing from
the Tx/Rx offset table. Add E1XX identifier and offsets to the device
list and offset table respectively.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
UHD requires a small amount of time to align multiple streams at
startup. Delay the startup by 100 ms relative to the queried device time
(actual delay inclusive of control latencies will be less).
The following error is only relevant to dual-channel UHD devices (e.g.
Fairwaves UmTRX and Ettus B210).
UHD Error:
The receive packet handler failed to time-align packets.
1002 received packets were processed by the handler.
However, a timestamp match could not be determined.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Recent versions of UHD require setting the sample rate before creating
streamers otherwise the following exception occurs.
Boost_105300; UHD_003.007.000-0-g7fef199d
terminate called after throwing an instance of
'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::math::rounding_error> >'
what(): Error in function boost::math::round<d>(d): Value -nan can not be represented in the target integer type.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Allow command line setting of the DSP frequency in UHD. All channels
will be tuned with the same offset. Dual-channel tuning with the B210,
which uses a single LO, will override the command line offset value
and set the DSP frequency automatically.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
The main difference between existing UmTRX dual channel is the
single LO on B210 transmit and receive front-ends vs. independent
tuning paths. In order to support dual-ARFCN frequencies, baseband
offset conversion must be applied by tuning the FPGA CORDIC for
each channel. For B210, the following tuning order is applied.
1. If the new frequency of channel A is within the baseband range
of channel B, then retune both channels with the RF centered
and equal valued positive and negative baseband shifts.
2. If the new frequency of channel A is not with the baseband range
of channel B, then retune channel A directly (without manual
applied offset). Channel B will no longer be tuned to the
previous frequency.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
With dual-channels on B210, we lose the ability to reset both
channels to a synchronized state. Instead, let the timestamp
clock start with an arbitary value, which is the first
timestamp received from the device, instead of a near-zero
value. This approach also makes integration for device, in
general, with free-running timestamp clocks.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Change from the original USRP1 rate of 52 MHz. On B2XX we can use
26 MHz, which is closer to the default 32 MHz of the device.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Burst selection at a particular time works in the following order
of priority.
1. Slot is disabled with channel combination set to NONE (default)
1. Burst exists in priority queue for the current time.
2. Filler table entry is used
This patch sets default behaviour to force all filler table entries
to zero and disallows filler table changes. This effectively means
that only bursts received from upper layers will be transmitted and
nothing will be automatically transmitted in the absence or delay
of incoming burts at a particular time.
New Command line option "Enable C0 filler table" allows reverting
to previous idle burst generation and retransmission behaviour on
TRX0. Retransmission cannot be enabled on non-C0 channels.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
We don't require any parameters stored in the configuration table,
so don't bother with the existence of the persistent database file.
This also removes an unnecessary step during initial setup since
relevant parameters can be configured from the command line.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Equalization is currently disabled by default. As such, we don't need to
run channel estimates or even track the update state, which would
otherwise be allocating/decallocating the channel state vector at
regular intervals.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
On startup errors we get a segfault if we stop and shutdown. This
is because we try to send a stop stream command to the device before
it has been created. Setup a check for running status before
attempting to stop the physical device.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Create new main executable with full command line option parsing
of relevant parameters. Database configuration table still exists
(and must exist because of the global gConfig object), but can
be bypassed with command line options.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
We support one TSC value per each transceiver object. Only channel
zero can set this value. Other channels can attempt to set the TSC
value, but will error if the TSC does not match the existing value.
In either case, non-zero channels do not manipulate the gloabl TSC
setting.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Each ARFCN channel may be independently configureted and possibly on
separate hardware, so don't share a single vector for noise estimate
calculations. Allow a non-pointer based iterator so we can get away
with using the default copy constructor.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
The transceiver has the ability to detect bursts below the noise floor,
but little hope in successful decoding, so don't even try. We still use
the detected burst to differentiate against noise vs actual data.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
In errant cases, GSM core may send bursts with invalid slot values,
which is allowed by the GSM::Time object. If we find a burst like this
coming into the transceiver, then drop it immediately.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
This patch add support for dual channel diversity on the receive
path. This allows two antennas two shared antennas to be used for
each ARFCN handling channel in the receiver. This configuration
may improvde performance in multi-path fading environments,
however, noise andpotential interference levels are increased due
to the higher bandwidth used.
The receive path is oversampled by a factor of four for a rate
of 1.083333 Msps. If the receive paths are tuned within a
maximum channel spacing (currently set at 600 kHz), then both
ARFCN frequencies are processed by each channel of the receiver.
Otherwise, the frequency shifted diversity path is disabled and
standard non-diversity operation takes place.
Diversity processing is handled by selecting the path with the
higheset energy level and discarding the burst on the second
path. Selection occurs on a burst-by-burst basis.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Separate the large pullRadioVector() call, which forms the central
portion of the receive path burst processing. Break out RACH, normal
burst, and demodulation into separate methods. This makes the burst
handling from the FIFO read to soft bit output somewhat more
manageable.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
The call into table lookup will loop on values outside of the
table range. With continuously increasing phase, this leads
to an eventual permanent hard spin. Wrap the phase value to
prevent that from happening.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
As we add more channel combintions including but not limited to
new devices, signal processing schemes, and diversity, we'll
need to handle more special cases. Add string descriptions for
just a bit more sanity.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
This patch allows multiple signalVectors to be stored within
a single radioVector object. The motivation is to provide
a facility for diversity and/or MIMO burst handling. When
no channel value is specified, single channel bevhaviour
is maintained.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Stack allocating the correlation output generates a call to the copy
constructor of an zero valued vector. We can avoid this extra copy
constructor with a pointer reference and dynamic allocation.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Allow non-in-place use of the delay setting. Internally, the delay call
creates a new vector and copies the contents back into the original.
Instead, provide the option to return the computed output vector
directly and remove an an extra copy in the process.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
On Beagle Board the call into the sinc() function is generating a lot of
load on the peak interpolation. Simplify the sinc() function with a
dedicated table lookup. Eventually, this table may be removed in favour
of using a precomputed filterbank for fractional delay determination.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Set a transceiver high level length value that specifies the largest
number of complex or real filter taps that we will encounter. This
allows preallocation of head room and prevents an extra allocation and
copy on every incoming receive burst.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
With testing on current UHD releases, currently 003.005.xxx series,
timeout errors on both receive and transmit are recoverable on network
and USB based devices. Remove the fatal error conditions.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Clock indications passed up to GSM core originate on the transciever
downlink side. Set priority to keep the flow of clock updates
consistent.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
This includes ARM Cortex A8 and A15 powered device such as Beagle
Board, Gumstix driven E100 USRP, and Arndale board. Set the reduced
SPS value automatically for the user.
For x86, if we don't support SSE3, then the architecture is
probably ancient and not with using. Drop the sampling down anyways
to at least make an attempt. Non floating point SIMD devices (e.g.
Raspberry Pi) also fall in this category
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Preallocate and compute a bank of fractional sample delay filters.
The number of filters to allocate is specified by the DELAYFILTS
preprocessor definition with a default value of 64. The filters
themselves are sinc pulse generated with 20 taps and Blackman-harris
windowed .
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Currently the code allocations a signalVector and then copies
into a radioVector. This is unnecessary because the latter is
a derived class making the first allocation unnecessary.
Modify the radioVector constructor to allow direct use in the
case above.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
This prevents the use of a copy constructor in the downlink
modulator and prevents a secondary memory allocation during
the convolution. Avoid both cases by dynamically allocating
with preloaded head room. The latter provides enough memory
before the first sample in the burst to cover the length
of the filter taps.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Complex-complex block multiples are used for phase rotation of
bursts. Optimization targeted from perf profiling.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
B2xx is a USB based device so use the USRP1 based adaptive flow
control window for transmit bursts. This adds additional stability
primarily on ARM platforms.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Similar to the existing Intel SSE cases, add support for NEON vector
floating point SIMD processing. In this case, use ARM assembly
directly as the NEON intrinsics do not generate preferential code
output.
Currently support NEON vectorized convolution and floating point
integer conversions.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
This patch primarily addresses devices with multiple RF front end
support. Currently device support is limited to UmTRX.
Vectorize transceiver variables to allow multiple asynchronous
threads on the upper layer with single downlink and uplink threads
driving the UHD I/O interface synchronously.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
USRPping and sigProcLibTest are in an unmaintained state,
while the intended functionality remains unknown. Stored
filter taps are also unused and should also be removed.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Collect the slot information into an indpendent state object. This
will allow us to easily create multiple instances of internal state
variables without having to replicate the transceiver object itself.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
For multiple transceiver connections, it is inappropriate to
allocate all sockets in the transceiver constructor due to not
knowing how many connections are avaialble in advance and for
error checking purposes. Instead, store the base socket address
port combination and setup the sockets in the initialization
call.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
The current status and operability of this compile option is
unknown. Remove due to lack of use, demand, and maintenance.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
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>
Currently the default configuration is to not build the full
transceiver, which is pointless. Set the UHD driver, which
includes either Ettus or Fairwaves variants, as the default.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Move x86 specific files into their own directory as this
area is about to get crowded with the addition of ARM
support.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Remove the built time resampling selection and link both options.
Move the normal push/pullBuffer() calls back to the base class and
overload them in the inherited resampling class.
USRP2/N2xx devices are the only devices that require resampling so
return that resampling is necessary on the device open(), which is
the point at which the device type will be known.
The GSM transceiver only operates at a whole number multiple of
the GSM rate and doesn't care about the actual device rate and
if resampling is used. Therefore GSM specific portion of the
transceiver should only need to submit the samples-per-symbol
value to the device interface.
Then, the device should be able to determine the appropriate
sample rate (400 ksps or 270.833 ksps) and if resampling is
appropriate.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
The transceiver only uses a single integer oversampling value,
which is more simply referred to as samples-per-symbol.
mRadioOversampling --> mSPS
mTransceiverOversampling (removed)
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Periodic timing alignment should never be required for UHD devices,
though the mechanism was used as a fallback mechanism should UHD
not properly recover after an underrun - as may occur in old
003.003.000 based revisions. This issue is not a concern in more
recent UHD releases and deprecates this code for legacy USRP1
use only.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
Previously, two timing correction values were used for UHD devices
depending on the sample rate of 270.833e3 or 400e3 for native GSM or
resampled device rate respectively. The correction values compensate
for residual timing effects due to analog component delays, filters
lag times, and general fudge factors. These values are device
specific and over-generalized by the two value configuration.
This patch adds the following struct to store these correction
values by device type and sample rate - through samples-per-symbol.
struct uhd_dev_offset {
enum uhd_dev_type type;
int sps;
double offset;
};
Signed-off-by: Thomas Tsou <tom@tsou.cc>
UHD device type was previously detected, but only categorized in
terms of bus type, USB or Ethernet, and sample rate capability.
With the number of supported device increasing, we can no longer
easily group devices since we need to handle more and more
device-specific peculiarities. Some of these factors are managed
internally by the UHD driver, but other factors (e.g. timing
offsets) are specific to a single device.
Start by maintaining an enumerated list of relevant device types
that we can use for applying device specific operations. Also
rename the USB/Ethernet grouping to transmit window type because
that's what it is.
enum uhd_dev_type {
USRP1,
USRP2,
B100,
NUM_USRP_TYPES,
};
Signed-off-by: Thomas Tsou <tom@tsou.cc>
This patch is long overdue and can now be merged after better understanding
of timestamp stability issues. UHD tick / timespec conversions were
generally used with the streamer interface, though these calls are actually
independent change sets. The combination would lead to internal rounding
errors and a timing drift most notably on B100 running at GSM symbol
rate multiples. There are no known issues, however, with the streamer code
itself.
The aforementioned issue was discovered in test code only, which was never
merged to mainline.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
The correlation starting point for normal burst training sequence
calculation should be a scaled value of the same symbol regardless
of the samples-per-symbol used. Use of 2 samples-per-symbols double
the index values, but yields the following outputs, which results
in a late time-of-arrival value at the output of the correlation.
This patch modifies the parameter calculation accordingly.
1 sps parameters
maxTOA = 3
spanTOA = 5;
startIx = 61;
endIx = 87;
windowLen = 26;
corrLen = 7;
2 sps parameters (errant case)
maxTOA = 6;
spanTOA = 10;
startIx = 112;
endIx = 184;
windowLen = 72;
corrLen =13;
2 sps parameters (corrected)
maxTOA = 6;
spanTOA = 10;
startIx = 122;
endIx = 174;
windowLen = 52;
corrLen =13;
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@5183 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Although currently unsupported in GSM core, enable TCH/H
support in Transceiver52M for testing and future availability.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@5169 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Without this patch, if SAMPSPERSYM is set bigger than 1, then
erratic behaviour will occur.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@4633 19bc5d8c-e614-43d4-8b26-e1612bc8e597
The adaptive energy detection threshold does not scale relative
to signal level. In other words, the adjustment factor will be
the same whether the at 40% of signal level or 4%. If the receive
gain is reduced by a large amount, suppose 20 dB, the receiver
may take minutes to adjust to the new level.
When the receive gain is changed, reset the threshold back to
the initial level. This reduces issues of runtime gain adjustment
and prevents blocking bursts while the threhold level slowly
adjusts.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@4595 19bc5d8c-e614-43d4-8b26-e1612bc8e597
1)I did an experiment and compiled OpenBTS with clang yesterday, which
immediately highlighted two potential bugs in the Transceiver52 code.
I'm not sure they are indeed bugs and not the intended behavior, but
they look very much like that. The first one is below and the second
one is in the following mail.
GSM::Time() arguments are defined like #define USB_LATENCY_INTRVL
(10,0), which means that they are expanded into GSM::Time((10,0)).
This expression is a GSM::Time() with a single parameter where (10,0)
return value of the last argument, 0 in this case. I.e.
GSM::Time((10,0)) is equivalent to GSM::Time(0). I think this was not
the intention.
2) Printing \n after every complex number breaks output when you want to
print it in a single line, e.g. in many debug output.
I do not claim any copyright over this change, as it's very basic.
Looking forward to see it merged into mainline.
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@4515 19bc5d8c-e614-43d4-8b26-e1612bc8e597
UHD accepts optional 'args' that can be used for device descriptions
such as IP address, device type, etc. Allow these to be passed in on
the transceiver command line as the third argument (number of supported
carriers is the second argument). This option benefits those who may
have multiple UHD devices attached to a single system.
This option is not yet supported by GSM core and requires starting the
transceiver independently on the command line. This option has no
effect when USRP1 is used.
Signed-off-by: Thomas Tsou <tom@tsou.cc>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@4315 19bc5d8c-e614-43d4-8b26-e1612bc8e597
The appearance of underruns on B100 due to the latency transmit
window scares people. These should not be logged at ERROR level
because the events are generally not real errors. So use the same
behaviour of USRP1 of not logging these events. The presence of
underrun events can be determined by changes in the latency window
that is shown with log level set at INFO.
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@3988 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Allowing the underrun flag to reset will prevent a single event from
causing large jumps in the transmit latency threshold. This should
keep unreasonable timing latencies from occurring (e.g. latencies of
20+ frames).
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@3981 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Put a floor on the transmit latency of the B100 in order to suppress
underruns in typical conditions. Empirical data from a handful of
relatively recent machines shows that the B100 will underrun when
the transmit threshold is reduced to a time of 6 and a half frames,
so we set a minimum 7 frame threshold.
The overall benefit should be marginal and may increase the
possibility of bursts arriving stale (after the trasmit deadline),
but will reduce the number of alarming UHD related messages that
appear in the log file.
This patch is UHD and B100 specific - USRP1 is unaffected.
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@3980 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Transmit gain setting would deceptively set the receive
gain instead. Since transmit attenuation is a combination
of RF gain and digital scaling, this major copy/paste bug
may have gone unnoticed by many users.
Reported-by: Robin Coxe <coxe@close-haul.com>
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@3309 19bc5d8c-e614-43d4-8b26-e1612bc8e597
The "Loss of monotonic time" error occurs when a timestamp
arrives from the device that is earlier in time than the
previous timestamp. The output is an ALERT level message
generally accompanied by a transmit side timeout from the
device.
UHD: Loss of monotonic time
UHD: Loss of monotonic time
UHD: Device send timed out
Add to the error description the timestamp values that
generated the error and output with ALERT rather than
ERR log.
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@3307 19bc5d8c-e614-43d4-8b26-e1612bc8e597
The failure "UHD make failed" implies that a suitable device
was found, but construction failed. Output the the found
target device information along with message.
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@3181 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Unrecoverable device errors include send and receive
timeouts and mangled packets. Other device errors, such
as non-monotonic timestamps are sometimes recoverable
through a soft restart.
These fatal are generally limited to development
versions of UHD driver or device firmware, but can occur
in release versions.
Alert user on such device errors along with current UHD
version.
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@3012 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Device errors regarding properties such as sample
rate or frequency tuning are almost always fatal and
lead to the common error "assuming TRX is dead".
Make sure that these errors are clearly presented to
the user.
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@2700 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Perform a UHD device search before constructing the object,
and inform the user if no device is found.
No device found is the most common reason for the transceiver
to fail with the dreaded error "assuming TRX is dead".
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@2699 19bc5d8c-e614-43d4-8b26-e1612bc8e597
This configuration is invalid because of FPGA based timestamp
support for the USRP1 in the UHD driver.
Kindly inform the user to recompile with libusrp support from
GNU Radio.
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@2698 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Before setting the master clock rate, make sure that the
device is capable of being set. For now, assume that devices
that operate with default clock rates above 64 MHz,
specifically USRP2/N200/N210, cannot be set at 52 MHz.
Inform the user that these devices can be used with the
compile time option of host based resampling.
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@2697 19bc5d8c-e614-43d4-8b26-e1612bc8e597
It was possible to reach a state where a resampled burst would
overrun the transmit output buffer and corrupt the global
allocated signal vectors. The result was a segmentation fault
when attempting to access heap allocated signal vectors since
the pointers were garbage.
Whether the segfault occured or not appears to depend on the
memory location of the signal vector pointers, since it does
not occur on all systems.
Double buffer size to accomodate an incoming burst plus up to
a full chunk that may be remaining from the previous resampling
operation.
Signed-off-by: Thomas Tsou <ttsou@vt.edu>
git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@2691 19bc5d8c-e614-43d4-8b26-e1612bc8e597
Alexander Chemeris