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Diffstat (limited to 'doc/manuals/chapters')
| -rw-r--r-- | doc/manuals/chapters/code-architecture.adoc | 141 | ||||
| -rw-r--r-- | doc/manuals/chapters/configuration.adoc | 85 | ||||
| -rw-r--r-- | doc/manuals/chapters/control.adoc | 12 | ||||
| -rw-r--r-- | doc/manuals/chapters/counters.adoc | 4 | ||||
| -rw-r--r-- | doc/manuals/chapters/counters_generated.adoc | 7 | ||||
| -rw-r--r-- | doc/manuals/chapters/overview.adoc | 62 | ||||
| -rw-r--r-- | doc/manuals/chapters/running.adoc | 19 | ||||
| -rw-r--r-- | doc/manuals/chapters/trx-architectures.adoc | 34 | ||||
| -rw-r--r-- | doc/manuals/chapters/trx-backends.adoc | 46 | ||||
| -rw-r--r-- | doc/manuals/chapters/trx-devices.adoc | 90 |
10 files changed, 500 insertions, 0 deletions
diff --git a/doc/manuals/chapters/code-architecture.adoc b/doc/manuals/chapters/code-architecture.adoc new file mode 100644 index 0000000..18d0e3a --- /dev/null +++ b/doc/manuals/chapters/code-architecture.adoc @@ -0,0 +1,141 @@ +[[code_architecture]] +== Code Architecture + +[[fig-code-architecture-general]] +.General overview of main OsmoTRX components +[graphviz] +---- +digraph hierarchy { +node[shape=record,style=filled,fillcolor=gray95] +edge[dir=back, arrowtail=empty] + +2[label = "{Transceiver|+ constructor()\l+ destructor()\l+ init()\l+ numChans()\l+ receiveFIFO()\l+ setSignalHandler()}"] +3[label = "{RadioInterface|...}"] +4[label = "{RadioInterfaceResamp|...}"] +5[label = "{RadioInterfaceMulti|...}"] +6[label = "{RadioDevice|...}"] +7[label = "{UHDDevice|...}"] +8[label = "{LMSDevice|...}"] +9[label = "{USRPDevice|...}"] + +2->3[arrowtail=odiamond] +3->4[constraint=false] +3->5[constraint=false] +3->6[arrowtail=odiamond] +6->7 +6->8 +6->9 +} +---- + +[[fig-code-architecture-threads]] +.Example of thread architecture with OsmoTRX configured to use 2 logical RF channels (Trx=Transceiver, RI=RadioIface) +[graphviz] +---- +digraph hierarchy { +node[shape=record,style=filled,fillcolor=gray95] + +trans [label="Transceiver"]; +radioiface [label="RadioInterface"]; +radiodev [label="RadioDevice"]; + +trans:nw->trans:ne [label="Trx.ControlServiceLoop_0"]; +trans:nw->trans:ne [label="Trx.ControlServiceLoop_1"]; +trans:w->radioiface:w [label="Trx.TxPriorityQueueServiceLoop_0"]; +trans:w->radioiface:w [label="Trx.TxPriorityQueueServiceLoop_1"]; +radioiface:e->trans:e [label="Trx.RxServiceLoop_0"]; +radioiface:e->trans:e [label="Trx.RxServiceLoop_1"]; +radioiface->radiodev[label="RI.AlignRadioServiceLoop"]; +radioiface:sw->radiodev:nw [label="Trx.TxLowerLoop"]; +radiodev:ne->radioiface:se [label="Trx.RxLowerLoop"]; +} +---- + +[[code_component_transceiver]] +=== Transceiver + +The Transceiver is the main component managing the other components running in +the OsmoTRX process. There's a unique instance per process. + +This class is quite complex from code point of view, as it starts lots of +different threads and hence the interaction with this class from the outside is +quite limited. Only interaction possible is to: + +* `Transceiver()`: Create an instance through its constructor, at this time most + configuration is handed to it. +* `init()`: Start running all the threads. +* `receiveFIFO()`: Attach a `radioInterface` channel FIFO in order to use it. +* `setSignalHandler()`: Used to set up a callback to receive certain events + asynchronously from the Transceiver. No assumptions can be made about from + which thread is the callback being called, which means multi-thread locking + precautions may be required in certain cases, similar to usual signal handler + processing. One important event received through this path is for instance + when the Transceiver detected a fatal error which requires it to stop. Since + it cannot stop itself (see destructor below), stopping procedure must be + delegated to the user who created the instance. +* `~Transceiver()`: The destructor, which stops all running threads created at + `init()` time. Destroying the object is the only way to stop the `Transceiver` + completely, and must be called from a thread not managed by the + `Transceiver`, otherwise it will deadlock. Usually it is stopped from the main + thread, the one that called the constructor during startup. + +During `init()` time, `Transceiver` will create a noticeable amount of threads, +which may vary depending on the amount of RF channels requested. + +Static amount of Threads (1 per `Transceiver` instance): + +* `RxLowerLoop`: This thread is responsible for reading bursts from the + `RadioInterface`, storing them into its FIFO and sending Clock Indications + (<<trx_if_clock_ind>>) to _osmo-bts_trx_. +* `TxLowerLoop`: Manages pushing bursts from buffers in the FIFO into the + `RadioInterface` at expected correct time based on the Transceiver clock. + +Dynamic amount of Threads (1 per RF logical channel on the `Transceiver` instance): + +* `ControlServiceLoop`: Handles commands from the Per-ARFCN Control Interface + socket (<<trx_if_control>>). Each thread is responsible for managing one + socket related to one ARFCN or which is the same, to one RF logical channel. + These are the only threads expected to use the private `start()` and `stop()` + methods of the `Transceiver()` class, since those methods don't stop any of + the `ControlServiceLoop` threads as they must keep running to handle new + commands (for instance, to re-start processing samples with the _POWERON_ + command). +* `RxServiceLoop`: Each thread of this type pulls bursts from the + `RadioInterface` FIFO for one specific logical RF channel and handles it + according to the slot and burst correlation type, finally sending proper data + over the TRX Manager UDP socket (<<trx_if>>). +* `TxPriorityQueueServiceLoop`: Blocks reading from one ARFCN specific TRX + Manager UDP socket (<<trx_if>>), and fills the `RadioInterface` with it + setting clock related information. + +[[code_component_radioiface]] +=== RadioInterface + +The `RadioInterface` sits between the `Transceiver` and the `RadioDevice`, and +provides extra features to the pipe like channelizers, resamplers, Tx/Rx +synchronization on some devices, etc. + +If the `RadioDevice` it drives requires it (only _USRP1_ so far), the +`RadioIntercace` will start and manage a thread internally called +`AlignRadioServiceLoop` which will align current RX and TX timestamps. + +Different features are offered through different `RadioInterface` subclasses +which are selected based on configuration and device detected at runtime. Using +these features may impact on the amount of CPU required to run the entire pipe. + +==== RadioInterfaceResamp + +This subclass of `RadioInterface` is automatically selected when some known +specific UHD are to be used, since they require resampling to work properly. +Some of this devices are for instance Ettus B100, USRP2 and X3XX models. + +==== RadioInterfaceMulti + +This subclass of `RadioInterface` is used when <<multiarfcn_mode>> is requested. + +[[code_component_radiodev]] +=== RadioDevice + +The `RadioDevice` class is responsible for driving the actual Hardware device. +It is actually only an interface, and it is implemented in each backend which in +turn becomes a specific OsmoTRX binary, see <<trx_backends>>. diff --git a/doc/manuals/chapters/configuration.adoc b/doc/manuals/chapters/configuration.adoc new file mode 100644 index 0000000..87d7903 --- /dev/null +++ b/doc/manuals/chapters/configuration.adoc @@ -0,0 +1,85 @@ +== Configuring OsmTRX + +OsmoTRX will read the configuration at startup time and configure the +transceiver accordingly after validating the configuration. + +OsmoTRX can handle several TRX channels, but at least one must be configured in +order to be able to start it successfully. Channels must be present in the +configuration file in incremental order, starting from 0 and be consecutive. + +Example configuration files for different devices and setups can be found in +`doc/examples/` in 'osmo-trx' git repository. + +=== Documented example + +.Example: Static GGSN/APN configuration (single catch-all GGSN) +---- +trx + bind-ip 127.0.0.1 <1> + remote-ip 127.0.0.1 <2> + base-port 5700 <3> + egprs disable <4> + tx-sps 4 <5> + rx-sps 4 <6> + chan 0 <7> + tx-path BAND1 <8> + rx-path LNAW <9> +---- +<1> Configure the local IP address at the TRX used for the connection against `osmo-bts-trx`. +<2> Specify the IP address of `osmo-bts-trx` to connect to. +<3> Specify the reference base UDP port to use for communication. +<4> Don't enable EDGE support. +<5> Use 4 TX samples per symbol. This is device specific. +<6> Use 4 RX samples per symbol. This is device specific. +<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). + +[[multiarfcn_mode]] +=== 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 127.0.0.1 + osmotrx ip remote 127.0.0.1 + 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 +---- +trx + ... + multi-arfcn enable + chan 0 + chan 1 +---- diff --git a/doc/manuals/chapters/control.adoc b/doc/manuals/chapters/control.adoc new file mode 100644 index 0000000..168769a --- /dev/null +++ b/doc/manuals/chapters/control.adoc @@ -0,0 +1,12 @@ +[[control]] +== Control interface + +The actual protocol is described in <<common-control-if>>, the variables +common to all programs using it are described in <<ctrl_common_vars>>. Here we +describe variables specific to OsmoTRX. + +.Variables available over control interface +[options="header",width="100%",cols="20%,5%,5%,50%,20%"] +|=== +|Name|Access|Trap|Value|Comment +|=== diff --git a/doc/manuals/chapters/counters.adoc b/doc/manuals/chapters/counters.adoc new file mode 100644 index 0000000..7fbb10c --- /dev/null +++ b/doc/manuals/chapters/counters.adoc @@ -0,0 +1,4 @@ +[[counters]] +== Counters + +include::./counters_generated.adoc[] diff --git a/doc/manuals/chapters/counters_generated.adoc b/doc/manuals/chapters/counters_generated.adoc new file mode 100644 index 0000000..b40dc37 --- /dev/null +++ b/doc/manuals/chapters/counters_generated.adoc @@ -0,0 +1,7 @@ +// autogenerated by show asciidoc counters +These counters and their description based on OsmoTRX 0.2.0.61-408f (OsmoTRX). + +// generating tables for rate_ctr_group +// generating tables for osmo_stat_items +// generating tables for osmo_counters +// there are no ungrouped osmo_counters diff --git a/doc/manuals/chapters/overview.adoc b/doc/manuals/chapters/overview.adoc new file mode 100644 index 0000000..785e26b --- /dev/null +++ b/doc/manuals/chapters/overview.adoc @@ -0,0 +1,62 @@ +[[chapter_introduction]] +== Overview + +[[intro_overview]] +=== About OsmoTRX + +OsmoTRX is a C/C++ language implementation of the GSM radio modem, +originally developed as the 'Transceiver' part of OpenBTS. This radio +modem offers an interface based on top of UDP streams. + + +The OsmoBTS bts_model code for OsmoTRX is called +`osmo-bts-trx`. It implements the UDP stream interface of +OsmoTRX, so both parts can be used together to implement a complete GSM +BTS based on general-purpose computing SDR. + +As OsmoTRX is general-purpose software running on top of Linux, it is +thus not tied to any specific physical hardware. At the time of this +writing, OsmoTRX supports a variety of Lime Microsystems and Ettus USRP SDRs via +the UHD driver, as well as the Fairwaves UmTRX and derived products. + +OsmoTRX is not a complete GSM PHY but 'just' the radio modem. This +means that all of the Layer 1 functionality such as scheduling, +convolutional coding, etc. is actually also implemented inside OsmoBTS. +OsmoTRX is a software-defined radio transceiver that implements the Layer 1 +physical layer of a BTS comprising the following 3GPP specifications: + +* TS 05.01 "Physical layer on the radio path" +* TS 05.02 "Multiplexing and Multiple Access on the Radio Path" +* TS 05.04 "Modulation" +* TS 05.10 "Radio subsystem synchronization + +As such, the boundary between OsmoTRX and `osmo-bts-trx` is at +a much lower interface, which is an internal interface of other more +traditional GSM PHY implementations. + +Besides OsmoTRX, there are also other implementations (both Free +Software and proprietary) that implement the same UDP stream based radio +modem interface. + +[[fig-gprs-pcubts]] +.GSM network architecture with OsmoTRX and OsmoBTS +[graphviz] +---- +digraph G { + rankdir=LR; + MS0 [label="MS"]; + MS1 [label="MS"]; + MS0->SDR[label="Um"]; + MS1->SDR [label="Um"]; + SDR -> OsmoTRX [label="Raw Samples"]; + OsmoTRX->BTS [label="bursts over UDP"]; + BTS->BSC [label="Abis"]; + BSC->MSC [label="A"]; + BTS->PCU [label="pcu_sock"]; + PCU->SGSN [label="Gb"]; + OsmoTRX [color=red]; +} +---- + +For more information see +https://osmocom.org/projects/osmotrx/wiki/OsmoTRX diff --git a/doc/manuals/chapters/running.adoc b/doc/manuals/chapters/running.adoc new file mode 100644 index 0000000..7ed2884 --- /dev/null +++ b/doc/manuals/chapters/running.adoc @@ -0,0 +1,19 @@ +== Running OsmoTRX + +The OsmoTRX executable (`osmo-trx`) offers the following command-line +options: + + +=== SYNOPSIS + +*osmo-trx* [-h] [-C 'CONFIGFILE'] + + +=== OPTIONS + +*-h*:: + Print a short help message about the supported options +*-C 'CONFIGFILE'*:: + Specify the file and path name of the configuration file to be + used. If none is specified, use `osmo_trx.cfg` in the current + working directory. diff --git a/doc/manuals/chapters/trx-architectures.adoc b/doc/manuals/chapters/trx-architectures.adoc new file mode 100644 index 0000000..66eae5e --- /dev/null +++ b/doc/manuals/chapters/trx-architectures.adoc @@ -0,0 +1,34 @@ +[[osmotrx_arch_support]] +== OsmoTRX hardware architecture support + +OsmoTRX comes out-of-the-box with several algorithms and operations +optimized for certain instruction-set architectures, as well as non-optimized +fall-back algorithms in case required instruction sets are not supported by the +compiler at compile time or by the executing machine at run-time. Support for +these optimized algorithms can be enabled and disabled by means of configure +flags. Accelerated operations include pulse shape filtering, resampling, +sequence correlation, and many other signal processing operations. + +On Intel processors, OsmoTRX makes heavy use of the Streaming SIMD Extensions +(SSE) instruction set. SSE3 is the minimum requirement for accelerated use. +SSE3 is present in the majority of Intel processors since later versions of the +Pentium 4 architecture and is also present on low power Atom processors. Support +is automatically detected at build time. SSE4.1 instruction set is supported +too. This feature is enabled by default unless explicitly disabled by passing +the configure flag _--with-sse=no_. When enabled, the compiler will build an +extra version of each of the supported algorithms using each of the supported +mentioned instruction sets. Then, at run-time, OsmoTRX will auto-detect +capabilities of the executing machine and enable an optimized algorithm using +the most suitable available (previously compiled) instruction set. + +On ARM processors, NEON and NEON FMA are supported. Different to the x86, there +is no auto-detection in this case, nor difference between compile and runtime. +NEON support is disabled by default and can be enabled by passing the flag +_--with-neon=yes_ to the configure script; the used compiler must support NEON +instruction set and the resulting binary will only run fine on an ARM board +supporting NEON extensions. Running OsmoTRX built with flag _--with-neon_ on a +board without NEON instruction set support, will most probably end up in the +process being killed with a _SIGILL_ Illegal Instruction signal by the operating +system. NEON FMA (Fused Multiply-Add) is an extension to the NEON instruction +set, and its use in OsmoTRX can be enabled by passing the _--with_neon_vfpv4_ +flag, which will also implicitly enable NEON support (_--with_neon_). diff --git a/doc/manuals/chapters/trx-backends.adoc b/doc/manuals/chapters/trx-backends.adoc new file mode 100644 index 0000000..8829fa6 --- /dev/null +++ b/doc/manuals/chapters/trx-backends.adoc @@ -0,0 +1,46 @@ +[[trx_backends]] +== OsmoTRX backend support + +[[backend_uhd]] +=== `osmo-trx-uhd` for UHD based Transceivers + +This OsmoTRX model uses _libuhd_ (UHD, USRP Hardware Driver) to drive the +device, that is configuring it and reading/writing samples from/to it. + +So far, this backend has been mostly used to drive devices such as the Ettus +B200 family and Fairwaves UmTRX family, and used to be the default backend used +for legacy @osmo-trx@ binary when per-backend binaries didn't exist yet. + +Any device providing generic support for UHD should theoretically be able to be +run through this backend without much effort, but pracitcal experience showed +that some devices don't play well with it, such as the LimeSDR family of +devices, which showed far better results when using its native interface. + +Related code can be found in the _Transceiver52M/device/uhd/_ directory in +_osmo-trx.git_. + +[[backend_lms]] +=== `osmo-trx-lms` for LimeSuite based Transceivers + +This OsmoTRX model uses LimeSuite API and library to drive the device, that is +configuring it and reading/writing samples from/to it. + +This backend was developed in order to be used together with LimeSDR-USB and +LimeSDR-mini devices, due to to the poor results obtained with the UHD backend, +and to simplify the stack. + +Related code can be found in the _Transceiver52M/device/lms/_ directory in +_osmo-trx.git_. + +[[backend_usrp1]] +=== `osmo-trx-usrp1` for libusrp based Transceivers + +This OsmoTRX model uses the legacy libusrp driver provided in GNU Radio 3.4.2. + +As this code was dropped from GNU Radio at some point and was found very +difficult to build, some work was done to create a standalone libusrp which can +be nowadays found as a separate git repository together with other osmocom git +repositories, in https://git.osmocom.org/libusrp/ + +Related code can be found in the _Transceiver52M/device/usrp1/_ directory in +_osmo-trx.git_. diff --git a/doc/manuals/chapters/trx-devices.adoc b/doc/manuals/chapters/trx-devices.adoc new file mode 100644 index 0000000..10c8529 --- /dev/null +++ b/doc/manuals/chapters/trx-devices.adoc @@ -0,0 +1,90 @@ +[[osmotrx_device_support]] +== OsmoTRX hardware device support + +OsmoTRX consists of a _common_ part that applies to all TRX devices as well as +_hardware-specific_ parts for each TRX device. The hardware-specific parts are +usually provided by vendor-specific or device-specific libraries that are then +handled by some OsmoTRX glue code presenting a unified interface towards the +rest of the code by means of a _RadioDevice_ class. + +The common part includes the core TRX architecture as well as code for +implementing the external interfaces such as the TRX Manager UDP socket, +control, and VTY interfaces. + +The hardware-specific parts include support for driving one particular +implementation of a radio modem. Such a physical layer +implementation can come in many forms. Sometimes it runs on a general +purpose CPU, sometimes on a dedicated ARM core, a dedicated DSP, a +combination of DSP and FPGA. + +Joining the common part with each of the available backends results in a +different binary with different suffix for each backend. For instance, when +OsmoTRX is built with UHD backend, an _osmo-trx-uhd_ binary is generated; when +OsmoTRX is built with LimeSuite backend, an _osmo-trx-lms_ binary is generated. +Build of different backend can be enabled and disabled by means of configure +flags, which can be found in each subsection relative to each backend below. + +[[dev_ettus_usrp1]] +=== Ettus USRP1 + +The binary _osmo-trx-usrp1_ is used to drive this device, see <<backend_usrp1>>. + +[[dev_ettus_b200]] +=== Ettus B200 + +The binary _osmo-trx-uhd_ is used to drive this device, see <<backend_uhd>>. + +Comes only with 1 RF channel. It can still be used in a multi-TRX setup by using +the <<multiarfcn_mode>> feature. By using this feature, one can drive up to 3 +TRX (with the restrictions explained there). + +[[dev_ettus_b200]] +=== Ettus B210 + +The binary _osmo-trx-uhd_ is used to drive this device, see <<backend_uhd>>. + +Comes with 2 RF channels, which can be used to set up a multi-TRX BTS. However, +due to a shared local oscillator for both RF channels, ARFCN separation can be +up about 25 MHz. + +This device also supports the <<multiarfcn_mode>> feature. By using this +feature, one can drive up to 3 TRX (with the restrictions explained there). +Please note that the above configurations cannot be combined, which means +maximum number of TRX one can achieve is 2 by using separate physical RF +channels, or 3 by using multi-ARFCN method. You cannot support, for example, 6 +ARFCN operation on B210 using 3 TRX on side A and another 3 TRX on side B. + +[[dev_limesdr_usb]] +=== LimeSDR-USB + +The binary _osmo-trx-lms_ is used to drive this device, see <<backend_lms>>. + +This device comes with 2 RF channels, so it should theoretically be possible to +run a multi-TRX setup with it, but there are yet no records that this kind of +setup was tested with this device. + +This device has 3 different Rx paths with different antenna connectors in the +PCB, each with a different frequency and bandwidth range. One should make sure +the physical antenna is connected to the correct connector matching the Rx path +you want to use. If one wants to be able to use the device in both 900 and 1800 +MHz GSM bands and easily switch between them, then Rx Path `LNAW` should be used +,since it is the only one covering both bands, and the antenna physically plugged +accordingly. Following example shows how to then configure _osmo-trx-lms_ to use +that Rx path to read samples. + +.Example: Configure osmo-trx-lms to use LNAW as Rx path and BAND1 as Tx Path +---- +trx + ... + chan 0 + tx-path BAND1 + rx-path LNAW +---- + +[[dev_limesdr_mini]] +=== LimeSDR-mini + +The binary _osmo-trx-lms_ is used to drive this device, see <<backend_lms>>. + +As a smaller brother of the [[dev_limesdr_usb]], this device comes only with 1 +RF channel. As a result, it can only hold 1 TRX as of today. |