Merge remote-tracking branch 'origin/shm-radio' into integration_2025_w13 (!3260)

Shared memory realtime radio simulation

Realtime and near-realtime RFSimulator alternative without channel modelling.
The purpose of this library is to allow realtime simulation of gNB and nrUE.

The library is loaded using --device.name vrtsim. The server side (gNB) should
also configure --vrtsim.role server and --vrtsim.timescale according to
requirements.

Limitations:
- Only 1UE-to-1gNB connection supported

Future work:
- Telnet API

ci-scripts/xml_files/container_5g_fdd_rfsim.xml

@@ -43,7 +43,7 @@
                 <class>Pull_Local_Registry</class>
                 <desc>Pull Images from Local Registry</desc>
                 <svr_id>0</svr_id>
-                <images>oai-gnb-asan oai-nr-ue-asan</images>
+                <images>oai-gnb oai-nr-ue</images>
         </testCase>
         <testCase id="800813">
                 <class>Create_Workspace</class>
@@ -134,7 +134,7 @@
                 <always_exec>true</always_exec>
                 <desc>Clean Test Images on Test Server</desc>
                 <svr_id>0</svr_id>
-                <images>oai-gnb-asan oai-nr-ue-asan</images>
+                <images>oai-gnb oai-nr-ue</images>
         </testCase>
 
 </testCaseList>

ci-scripts/yaml_files/5g_fdd_rfsimulator/docker-compose.yaml

@@ -86,8 +86,7 @@ services:
         cap_drop:
             - ALL
         environment:
-            USE_ADDITIONAL_OPTIONS: -E --rfsim --log_config.global_log_options level,nocolor,time
-            ASAN_OPTIONS: detect_leaks=0
+            USE_ADDITIONAL_OPTIONS: -E --log_config.global_log_options level,nocolor,time --device.name vrtsim --vrtsim.role server --vrtsim.timescale 0.5
         depends_on:
             - oai-ext-dn
         networks:
@@ -95,11 +94,13 @@ services:
                 ipv4_address: 192.168.71.140
         volumes:
             - ../../conf_files/gnb.sa.band66.106prb.rfsim.conf:/opt/oai-gnb/etc/gnb.conf
+            - tmp_data:/tmp/
         healthcheck:
             test: /bin/bash -c "pgrep nr-softmodem"
             interval: 10s
             timeout: 5s
             retries: 5
+        ipc: host
     oai-nr-ue:
         image: ${REGISTRY:-oaisoftwarealliance}/${NRUE_IMG:-oai-nr-ue}:${TAG:-develop}
         container_name: rfsim5g-oai-nr-ue
@@ -109,7 +110,7 @@ services:
             - NET_ADMIN  # for interface bringup
             - NET_RAW    # for ping
         environment:
-            USE_ADDITIONAL_OPTIONS: -E --rfsim -r 106 --numerology 1 --uicc0.imsi 208990100001100 --band 66 -C 2169090000 --CO -400000000 --ssb 378 --rfsimulator.serveraddr 192.168.71.140 --log_config.global_log_options level,nocolor,time
+            USE_ADDITIONAL_OPTIONS: -E -r 106 --numerology 1 --uicc0.imsi 208990100001100 --band 66 -C 2169090000 --CO -400000000 --ssb 378 --log_config.global_log_options level,nocolor,time --device.name vrtsim
         depends_on:
             - oai-gnb
         networks:
@@ -119,11 +120,13 @@ services:
              - /dev/net/tun:/dev/net/tun
         volumes:
             - ../../conf_files/nrue.uicc.conf:/opt/oai-nr-ue/etc/nr-ue.conf
+            - tmp_data:/tmp/
         healthcheck:
             test: /bin/bash -c "pgrep nr-uesoftmodem"
             interval: 10s
             timeout: 5s
             retries: 5
+        ipc: host
 
 networks:
     public_net:
@@ -142,3 +145,6 @@ networks:
                 - subnet: 192.168.72.128/26
         driver_opts:
             com.docker.network.bridge.name: "rfsim5g-traffic"
+
+volumes:
+    tmp_data:

cmake_targets/build_oai

@@ -485,7 +485,7 @@ function main() {
     # add some default libraries that should always be built
     # for eNB, gNB, UEs, simulators
     if [[ $gNB == 1 || $eNB == 1 || $UE == 1 || $nrUE == 1 || $SIMUS_PHY == 1 || $RU == 1 ]]; then
-      TARGET_LIST="$TARGET_LIST params_libconfig coding rfsimulator dfts params_yaml"
+      TARGET_LIST="$TARGET_LIST params_libconfig coding rfsimulator dfts params_yaml vrtsim"
     fi
 
     mkdir -p $DIR/$BUILD_DIR/build

common/utils/CMakeLists.txt

@@ -21,3 +21,4 @@ if (ENABLE_TESTS)
 endif()
 add_subdirectory(barrier)
 add_subdirectory(actor)
+add_subdirectory(shm_iq_channel)

common/utils/actor/CMakeLists.txt

 add_library(actor actor.c)
-target_include_directories(actor PUBLIC ./)
-target_link_libraries(actor PUBLIC thread-pool)
+# Only include header files due to issues with ODR in threadPool binaries
+target_include_directories(actor PUBLIC ./ ../threadPool/)
 if (ENABLE_TESTS)
   add_subdirectory(tests)
 endif()

common/utils/shm_iq_channel/CMakeLists.txt

+add_library(shm_td_iq_channel shm_td_iq_channel.c)
+target_include_directories(shm_td_iq_channel PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+
+if (ENABLE_TESTS)
+  add_subdirectory(tests)
+endif()

common/utils/shm_iq_channel/shm_td_iq_channel.h

+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+#ifndef SHM_IQ_CHANNEL_H
+#define SHM_IQ_CHANNEL_H
+
+#include "../threadPool/pthread_utils.h"
+#include <stdint.h>
+#include <stdbool.h>
+#include <semaphore.h>
+
+#define SHM_MAGIC_NUMBER 0x12345678
+
+/**
+ * ShmTdIqChannel is a shared memory bidirectional time domain IQ channel with a single clock
+ * source. The server (clock source) shall create the channel while the client should connect to
+ * it.
+ *
+ * To write samples, send them via a pointer passed to shm_td_iq_channel_tx.
+ * To read samples, receive them via a pointer passed to shm_td_iq_channel_rx. You can either wait until
+ * the sample are available using shm_td_iq_channel_wait or poll using shm_td_iq_channel_rx until the return
+ * value is not CHANNEL_ERROR_TOO_EARLY.
+ * To indicate that samples are ready to be read by the client, call shm_td_iq_channel_produce_samples
+ * (server only).
+ *
+ * The timestamps used in the API are in absolute samples from the time the client/server connection started.
+ */
+
+typedef enum IQChannelType { IQ_CHANNEL_TYPE_SERVER, IQ_CHANNEL_TYPE_CLIENT } IQChannelType;
+typedef uint32_t sample_t;
+typedef enum IQChannelErrorType {
+  CHANNEL_NO_ERROR,
+  CHANNEL_ERROR_TOO_LATE,
+  CHANNEL_ERROR_TOO_EARLY,
+  CHANNEL_ERROR_NOT_CONNECTED
+} IQChannelErrorType;
+
+typedef struct ShmTDIQChannel_s ShmTDIQChannel;
+
+/**
+ * @brief Creates a shared memory IQ channel.
+ *
+ * @param name The name of the shared memory segment.
+ * @param num_tx_ant The number of TX antennas.
+ * @param num_rx_ant The number of RX antennas.
+ * @return A pointer to the created ShmTDIQChannel structure.
+ */
+ShmTDIQChannel *shm_td_iq_channel_create(const char *name, int num_tx_ant, int num_rx_ant);
+
+/**
+ * @brief Connects to an existing shared memory IQ channel.
+ *
+ * @param name The name of the shared memory segment.
+ * @param timeout_in_seconds The timeout in seconds for the connection attempt.
+ * @return A pointer to the connected ShmTDIQChannel structure.
+ */
+ShmTDIQChannel *shm_td_iq_channel_connect(const char *name, int timeout_in_seconds);
+
+/**
+ * @brief Transmit data in the channel
+ *
+ * @param channel The ShmTDIQChannel structure.
+ * @param timestamp The timestamp for which to get the TX IQ data slot.
+ * @param num_samples The number of samples to write.
+ * @param antenna The antenna index.
+ * @param tx_iq_data The TX IQ data to write.
+ *
+ * @return CHANNEL_NO_ERROR if successful, error type otherwise
+ */
+IQChannelErrorType shm_td_iq_channel_tx(ShmTDIQChannel *channel,
+                                        uint64_t timestamp,
+                                        uint64_t num_samples,
+                                        int antenna,
+                                        const sample_t *tx_iq_data);
+
+/**
+ * @brief Receive iq data from the channel
+ *
+ * @param channel The ShmTDIQChannel structure.
+ * @param timestamp The timestamp for which to get the RX IQ data slot.
+ * @param num_samples The number of samples to read.
+ * @param antenna The antenna index.
+ * @param tx_iq_data pointer to the RX IQ data slot.
+ * @return CHANNEL_NO_ERROR if successful, error type otherwise
+ */
+IQChannelErrorType shm_td_iq_channel_rx(ShmTDIQChannel *channel,
+                                        uint64_t timestamp,
+                                        uint64_t num_samples,
+                                        int antenna,
+                                        sample_t *tx_iq_data);
+
+/**
+ * @brief Advances the time in the channel by specified number of samples
+ *
+ * @param channel The ShmTDIQChannel structure.
+ * @param num_symbols The number of samples to produce.
+ */
+void shm_td_iq_channel_produce_samples(ShmTDIQChannel *channel, uint64_t num_samples);
+
+/**
+ * @brief Wait until sample at the specified timestamp is available
+ *
+ * @param channel The ShmTDIQChannel structure.
+ */
+void shm_td_iq_channel_wait(ShmTDIQChannel *channel, uint64_t timestamp);
+
+/**
+ * @brief Checks if the IQ channel is connected.
+ *
+ * @param channel The ShmTDIQChannel structure.
+ * @return True if the channel is connected, false otherwise.
+ */
+bool shm_td_iq_channel_is_connected(const ShmTDIQChannel *channel);
+
+/**
+ * @brief Destroys the shared memory IQ channel.
+ *
+ * @param channel The ShmTDIQChannel structure.
+ */
+void shm_td_iq_channel_destroy(ShmTDIQChannel *channel);
+
+/**
+ * @brief Returns current sample
+ *
+ * @param channel The ShmTDIQChannel structure.
+ *
+ * @return Current time as sample count since beginning of transmission
+ */
+uint64_t shm_td_iq_channel_get_current_sample(const ShmTDIQChannel *channel);
+
+#endif

common/utils/shm_iq_channel/tests/CMakeLists.txt

+add_executable(test_shm_td_iq_channel test_shm_td_iq_channel.c)
+target_link_libraries(test_shm_td_iq_channel shm_td_iq_channel minimal_lib pthread)
+add_dependencies(tests test_shm_td_iq_channel)
+# Commented out due to issues with ASAN in the unit test docker container
+#add_test(test_shm_td_iq_channel ./test_shm_td_iq_channel)

common/utils/shm_iq_channel/tests/test_shm_td_iq_channel.c

+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <pthread.h>
+#include <errno.h>
+#include "assertions.h"
+
+#define SHM_CHANNEL_NAME "shm_iq_channel_test_file"
+#include "shm_td_iq_channel.h"
+
+void server(void);
+int client(void);
+
+enum { MODE_SERVER, MODE_CLIENT, MODE_FORK };
+int main(int argc, char *argv[])
+{
+  int mode = MODE_FORK;
+  if (argc == 2) {
+    if (strcmp(argv[1], "server") == 0) {
+      mode = MODE_SERVER;
+    } else if (strcmp(argv[1], "client") == 0) {
+      mode = MODE_CLIENT;
+    }
+  } else if (argc > 2) {
+    printf("Usage: %s [server|client]\n", argv[0]);
+    return 1;
+  }
+  switch (mode) {
+    case MODE_SERVER:
+      server();
+      break;
+    case MODE_CLIENT:
+      return client();
+      break;
+    case MODE_FORK: {
+      char file[256];
+      snprintf(file, sizeof(file), "/dev/shm/%s", SHM_CHANNEL_NAME);
+      remove(file);
+      int pid = fork();
+      if (pid == 0) {
+        server();
+      } else {
+        return client();
+      }
+    } break;
+  }
+
+  return 0;
+}
+
+const int num_updates = 50;
+const int num_samples_per_update = 30720;
+void *produce_symbols(void *arg)
+{
+  ShmTDIQChannel *channel = (ShmTDIQChannel *)arg;
+  for (int i = 0; i < num_updates; i++) {
+    shm_td_iq_channel_produce_samples(channel, num_samples_per_update);
+    usleep(20000);
+  }
+  return 0;
+}
+
+void server(void)
+{
+  int num_ant_tx = 1;
+  int num_ant_rx = 1;
+  ShmTDIQChannel *channel = shm_td_iq_channel_create(SHM_CHANNEL_NAME, num_ant_tx, num_ant_rx);
+  for (int i = 0; i < 10; i++) {
+    if (shm_td_iq_channel_is_connected(channel)) {
+      printf("Server connected\n");
+      break;
+    }
+    printf("Waiting for client\n");
+    sleep(1);
+  }
+  AssertFatal(shm_td_iq_channel_is_connected(channel), "Server failed to connect\n");
+
+  pthread_t producer_thread;
+  int ret = pthread_create(&producer_thread, NULL, produce_symbols, channel);
+  AssertFatal(ret == 0, "pthread_create() failed: errno %d, %s\n", errno, strerror(errno));
+
+  uint64_t timestamp = 0;
+  int iq_contents = 0;
+  while (timestamp < num_samples_per_update * num_updates) {
+    shm_td_iq_channel_wait(channel, timestamp + num_samples_per_update);
+    uint64_t target_timestamp = timestamp + num_samples_per_update;
+    timestamp += num_samples_per_update;
+    uint32_t iq_data[num_samples_per_update];
+    for (int i = 0; i < num_samples_per_update; i++) {
+      iq_data[i] = iq_contents;
+    }
+    int result = shm_td_iq_channel_tx(channel, target_timestamp, num_samples_per_update, 0, iq_data);
+    AssertFatal(result == CHANNEL_NO_ERROR, "Failed to write data\n");
+    iq_contents++;
+  }
+
+  printf("Finished writing data\n");
+
+  ret = pthread_join(producer_thread, NULL);
+  AssertFatal(ret == 0, "pthread_join() failed: errno %d, %s\n", errno, strerror(errno));
+  shm_td_iq_channel_destroy(channel);
+}
+
+int client(void)
+{
+  int total_errors = 0;
+  ShmTDIQChannel *channel = shm_td_iq_channel_connect(SHM_CHANNEL_NAME, 10);
+  for (int i = 0; i < 10; i++) {
+    if (shm_td_iq_channel_is_connected(channel)) {
+      printf("Client connected\n");
+      break;
+    }
+    printf("Waiting for server\n");
+    sleep(1);
+  }
+  AssertFatal(shm_td_iq_channel_is_connected(channel), "Client failed to connect\n");
+
+  uint64_t timestamp = 0;
+  int iq_contents = 0;
+
+  while (timestamp < num_samples_per_update * num_updates) {
+    shm_td_iq_channel_wait(channel, timestamp + num_samples_per_update);
+    // Server starts producing from second slot
+    if (timestamp > num_samples_per_update) {
+      uint64_t target_timestamp = timestamp - num_samples_per_update;
+      uint32_t iq_data[num_samples_per_update];
+      int result = shm_td_iq_channel_rx(channel, target_timestamp, num_samples_per_update, 0, iq_data);
+      AssertFatal(result == CHANNEL_NO_ERROR, "Failed to read data\n");
+      int num_errors = 0;
+      for (int i = 0; i < num_samples_per_update; i++) {
+        if (iq_data[i] != iq_contents) {
+          num_errors++;
+        }
+      }
+      if (num_errors) {
+        printf("Found %d errors, value = %d, reference = %d\n", num_errors, iq_data[0], iq_contents);
+        total_errors += num_errors;
+      }
+      iq_contents++;
+    }
+    timestamp += num_samples_per_update;
+  }
+
+  printf("Finished reading data\n");
+  shm_td_iq_channel_destroy(channel);
+  return total_errors;
+}

doc/README.md

@@ -118,6 +118,7 @@ Some directories under `radio` contain READMEs:
 - [BladeRF](../radio/BLADERF/README)
 - [IQPlayer](../radio/iqplayer/DOC/iqrecordplayer_usage.md), and [general documentation](./iqrecordplayer_usage.md)
 - [fhi_72](../radio/fhi_72/README.md)
+- [vrtsim](../radio/vrtsim/README.md)
 
 The other SDRs (AW2S, LimeSDR, ...) have no READMEs.
 

docker/Dockerfile.gNB.rhel9

@@ -72,6 +72,7 @@ COPY --from=gnb-build \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv.so \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv_ci.so \
     /oai-ran/cmake_targets/ran_build/build/libparams_yaml.so \
+    /oai-ran/cmake_targets/ran_build/build/libvrtsim.so \
     /usr/local/lib/
 
 COPY --from=gnb-base \

docker/Dockerfile.gNB.rocky

@@ -69,6 +69,7 @@ COPY --from=gnb-build \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv.so \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv_ci.so \
     /oai-ran/cmake_targets/ran_build/build/libparams_yaml.so \
+    /oai-ran/cmake_targets/ran_build/build/libvrtsim.so \
     /usr/local/lib/
 
 COPY --from=gnb-base \

docker/Dockerfile.gNB.ubuntu22

@@ -110,6 +110,7 @@ COPY --from=gnb-build \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv_5Gue.so \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv_rrc.so \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv_o1.so \
+    /oai-ran/cmake_targets/ran_build/build/libvrtsim.so \
     /usr/local/lib/
 
 # Now we are copying from builder-image the UHD files.

docker/Dockerfile.nrUE.rhel9

@@ -75,6 +75,7 @@ COPY --from=nr-ue-build \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv.so \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv_5Gue.so \
     /oai-ran/cmake_targets/ran_build/build/libparams_yaml.so \
+    /oai-ran/cmake_targets/ran_build/build/libvrtsim.so \
     /usr/local/lib/
 
 COPY --from=nr-ue-base \

docker/Dockerfile.nrUE.rocky

@@ -72,6 +72,7 @@ COPY --from=nr-ue-build \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv.so \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv_5Gue.so \
     /oai-ran/cmake_targets/ran_build/build/libparams_yaml.so \
+    /oai-ran/cmake_targets/ran_build/build/libvrtsim.so \
     /usr/local/lib/
 
 COPY --from=nr-ue-base \

docker/Dockerfile.nrUE.ubuntu22

@@ -110,6 +110,7 @@ COPY --from=nr-ue-build \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv_ciUE.so \
     /oai-ran/cmake_targets/ran_build/build/libtelnetsrv_5Gue.so \
     /oai-ran/cmake_targets/ran_build/build/libparams_yaml.so \
+    /oai-ran/cmake_targets/ran_build/build/libvrtsim.so \
     /usr/local/lib/
 
 # Now we are copying from builder-image the UHD files.

openair1/SIMULATION/TOOLS/sim.h

@@ -50,6 +50,7 @@ typedef enum {
 #define CHANMODEL_FREE_RSQRT_6     1<<1
 #define CHANMODEL_FREE_RSQRT_NTAPS 1<<2
 #define CHANMODEL_FREE_AMPS        1<<3
+#define SHR3 (jz = jsr, jsr ^= (jsr << 13), jsr ^= (jsr >> 17), jsr ^= (jsr << 5), jz + jsr)
 
 typedef enum {
   CORR_LEVEL_LOW,

radio/CMakeLists.txt

@@ -37,3 +37,8 @@ add_boolean_option(OAI_USRP OFF "Activate OAI's USRP driver" OFF)
 if(OAI_USRP)
   add_subdirectory(USRP)
 endif()
+
+add_boolean_option(VRTSIM_RADIO ON "Activate OAI's shared memory radio driver" OFF)
+if(VRTSIM_RADIO)
+  add_subdirectory(vrtsim)
+endif()

radio/vrtsim/CMakeLists.txt

+add_library(vrtsim MODULE vrtsim.c noise_device.c)
+set_target_properties(vrtsim PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
+target_link_libraries(vrtsim PRIVATE SIMU shm_td_iq_channel actor)
+add_dependencies(vrtsim generate_T)

radio/vrtsim/README.md

+# Overview
+
+This implements a shared memory realtime and near-realtime radio interface.
+This is performed using `shm_td_iq_channel` which handles the shared memory
+interface.
+
+# Limitations
+
+ - Only 1gNB to 1nrUE: gNB as a server, UE as a client.
+ - Server only accepts connections during device bringup. This means that
+   restarting the client will not make it reconnect, the server has to be
+   restarted as well.
+
+# Usage
+
+On the UE and gNB: use `device.name vrtsim` command line argument.
+
+Additionally on gNB use `vrtsim.role server` and optionally
+`vrtsim.timescale <timescale>` to set the timescale. Timescale 1.0
+is the default and means realtime.
+
+Channel modelling can be enabled by adding `vrtsim.chanmod 1` to the
+command line and should work the same as channel modelling in rfsimulator,
+see rfsimulator [documentation](../rfsimulator/README.md), provided that your
+CPU is fast enough.

radio/vrtsim/noise_device.c

+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+#include <pthread.h>
+#include <errno.h>
+#include "noise_device.h"
+
+// Use block size equal to cache size
+#define BLOCK_SIZE (64 / sizeof(float)) // 4 bytes per float
+// Use a power of 2 for block size length
+#define NUM_BLOCKS (8192)
+#define NOISE_VECTOR_LENGTH (BLOCK_SIZE * NUM_BLOCKS)
+
+static struct {
+  pthread_t noise_device_thread;
+  float noise[NOISE_VECTOR_LENGTH] __attribute__((aligned(64)));
+  float noise_power;
+  bool running;
+} state;
+
+static uint32_t jz, jsr = 123456789;
+static uint32_t random_uint(void)
+{
+  return SHR3;
+}
+
+static void generate_one_block_noise(int write_block_index, float noise_power)
+{
+  // Generate noise vector
+  float block[BLOCK_SIZE];
+  for (int i = 0; i < BLOCK_SIZE; i++) {
+    block[i] = noise_power * gaussZiggurat(0, 1);
+  }
+  // Write block to noise vector
+  memcpy(state.noise + write_block_index * BLOCK_SIZE, block, sizeof(block));
+}
+
+void *noise_device_thread_function(void *arg)
+{
+  while (state.running) {
+    // Generate noise vector
+    generate_one_block_noise(random_uint() % NUM_BLOCKS, state.noise_power);
+    usleep(10000);
+  }
+  return NULL;
+}
+
+void init_noise_device(float noise_power)
+{
+  for (int i = 0; i < NUM_BLOCKS; i++) {
+    generate_one_block_noise(i, noise_power);
+  }
+  int ret = pthread_create(&state.noise_device_thread, NULL, noise_device_thread_function, NULL);
+  AssertFatal(ret == 0, "pthread_create failed: %d, errno %d (%s)\n", ret, errno, strerror(errno));
+}
+
+void free_noise_device(void)
+{
+  state.running = false;
+  pthread_join(state.noise_device_thread, NULL);
+}
+
+void get_noise_vector(float *noise_vector, int length)
+{
+  int start_block = random_uint() % NUM_BLOCKS;
+  while (length > 0) {
+    int copy_size = min(length, (NUM_BLOCKS - start_block) * BLOCK_SIZE);
+    memcpy(noise_vector, &state.noise[start_block * BLOCK_SIZE], copy_size * sizeof(float));
+    start_block = 0;
+    length -= copy_size;
+    noise_vector += copy_size;
+  }
+}

radio/vrtsim/noise_device.h

+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+
+#ifndef NOISE_DEVICE_H
+#define NOISE_DEVICE_H
+
+#include "SIMULATION/TOOLS/sim.h"
+
+void init_noise_device(float noise_power);
+void free_noise_device(void);
+void get_noise_vector(float *noise_vector, int length);
+
+#endif