usrp_lib.cpp 21.5 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659
/*******************************************************************************
    OpenAirInterface 
    Copyright(c) 1999 - 2014 Eurecom

    OpenAirInterface is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.


    OpenAirInterface is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with OpenAirInterface.The full GNU General Public License is 
    included in this distribution in the file called "COPYING". If not, 
    see <http://www.gnu.org/licenses/>.

   Contact Information
   OpenAirInterface Admin: openair_admin@eurecom.fr
   OpenAirInterface Tech : openair_tech@eurecom.fr
   OpenAirInterface Dev  : openair4g-devel@lists.eurecom.fr
  
   Address      : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE

 *******************************************************************************/

/** usrp_lib.cpp
 *
 * Author: HongliangXU : hong-liang-xu@agilent.com
 */

#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <stdio.h>
#include <uhd/utils/thread_priority.hpp>
#include <uhd/usrp/multi_usrp.hpp>
#include <uhd/version.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/algorithm/string.hpp>
#include <iostream>
#include <complex>
#include <fstream>
#include <cmath>

#include "common_lib.h"
#ifdef __SSE4_1__
#  include <smmintrin.h>
#endif
 
#ifdef __AVX2__
#  include <immintrin.h>
#endif

typedef struct
{

  // --------------------------------
  // variables for USRP configuration
  // --------------------------------
  uhd::usrp::multi_usrp::sptr usrp;
  //uhd::usrp::multi_usrp::sptr rx_usrp;
  
  //create a send streamer and a receive streamer
  uhd::tx_streamer::sptr tx_stream;
  uhd::rx_streamer::sptr rx_stream;

  uhd::tx_metadata_t tx_md;
  uhd::rx_metadata_t rx_md;

  uhd::time_spec_t tm_spec;
  //setup variables and allocate buffer
  uhd::async_metadata_t async_md;

  double sample_rate;
  // time offset between transmiter timestamp and receiver timestamp;
  double tdiff;
  // use usrp_time_offset to get this value
  int tx_forward_nsamps; //166 for 20Mhz


  // --------------------------------
  // Debug and output control
  // --------------------------------
  int num_underflows;
  int num_overflows;
  int num_seq_errors;

  int64_t tx_count;
  int64_t rx_count;
  openair0_timestamp rx_timestamp;

} usrp_state_t;


static int trx_usrp_start(openair0_device *device)
{
  usrp_state_t *s = (usrp_state_t*)device->priv;

  // init recv and send streaming
  uhd::stream_cmd_t cmd(uhd::stream_cmd_t::STREAM_MODE_START_CONTINUOUS);
  cmd.time_spec = s->usrp->get_time_now() + uhd::time_spec_t(0.05);
  cmd.stream_now = false; // start at constant delay
  s->rx_stream->issue_stream_cmd(cmd);

  s->tx_md.time_spec = cmd.time_spec + uhd::time_spec_t(1-(double)s->tx_forward_nsamps/s->sample_rate);
  s->tx_md.has_time_spec = true;
  s->tx_md.start_of_burst = true;
  s->tx_md.end_of_burst = false;


  s->rx_count = 0;
  s->tx_count = 0;
  s->rx_timestamp = 0;

  return 0;
}

static void trx_usrp_end(openair0_device *device)
{
  usrp_state_t *s = (usrp_state_t*)device->priv;

  s->rx_stream->issue_stream_cmd(uhd::stream_cmd_t::STREAM_MODE_STOP_CONTINUOUS);

  //send a mini EOB packet
  s->tx_md.end_of_burst = true;
  s->tx_stream->send("", 0, s->tx_md);
  s->tx_md.end_of_burst = false;
  
}

static int trx_usrp_write(openair0_device *device, openair0_timestamp timestamp, void **buff, int nsamps, int cc, int flags)
{
  usrp_state_t *s = (usrp_state_t*)device->priv;
  s->tx_md.time_spec = uhd::time_spec_t::from_ticks(timestamp, s->sample_rate);
  if(flags)
    s->tx_md.has_time_spec = true;
  else
    s->tx_md.has_time_spec = false;

  if (cc>1) {
    std::vector<void *> buff_ptrs;
    for (int i=0;i<cc;i++) buff_ptrs.push_back(buff[i]);
    s->tx_stream->send(buff_ptrs, nsamps, s->tx_md);
  }
  else
    s->tx_stream->send(buff[0], nsamps, s->tx_md);
  s->tx_md.start_of_burst = false;

  return 0;
}

static int trx_usrp_read(openair0_device *device, openair0_timestamp *ptimestamp, void **buff, int nsamps, int cc)
{
   usrp_state_t *s = (usrp_state_t*)device->priv;
   int samples_received=0,i,j;
   int nsamps2;  // aligned to upper 32 or 16 byte boundary
#if defined(__x86_64) || defined(__i386__)
#ifdef __AVX2__
   __m256i buff_tmp[2][nsamps>>3];
   nsamps2 = (nsamps+7)>>3;
#else
   __m128i buff_tmp[2][nsamps>>2];
   nsamps2 = (nsamps+3)>>2;
#endif
#elif defined(__arm__)
   int16x8_t buff_tmp[2][nsamps>>2];
   nsamps2 = (nsamps+3)>>2;
#endif


  if (device->type == USRP_B200_IF) {  
    if (cc>1) {
    // receive multiple channels (e.g. RF A and RF B)
      std::vector<void *> buff_ptrs;
 
      for (int i=0;i<cc;i++) buff_ptrs.push_back(buff_tmp[i]);
      samples_received = s->rx_stream->recv(buff_ptrs, nsamps, s->rx_md);
    } else {
    // receive a single channel (e.g. from connector RF A)
      samples_received = s->rx_stream->recv(buff_tmp[0], nsamps, s->rx_md);
    }
   
  // bring RX data into 12 LSBs for softmodem RX
    for (int i=0;i<cc;i++) {
      for (int j=0; j<nsamps2; j++) {      
#if defined(__x86_64__) || defined(__i386__)
#ifdef __AVX2__
        ((__m256i *)buff[i])[j] = _mm256_srai_epi16(buff_tmp[i][j],4);
#else
        ((__m128i *)buff[i])[j] = _mm_srai_epi16(buff_tmp[i][j],4);
#endif
#elif defined(__arm__)
        ((int16x8_t*)buff[i])[j] = vshrq_n_s16(buff_tmp[i][j],4);
#endif
      }
    }
  } else if (device->type == USRP_X300_IF) {
    if (cc>1) {
    // receive multiple channels (e.g. RF A and RF B)
      std::vector<void *> buff_ptrs;
 
      for (int i=0;i<cc;i++) buff_ptrs.push_back(buff[i]);
      samples_received = s->rx_stream->recv(buff_ptrs, nsamps, s->rx_md);
    } else {
    // receive a single channel (e.g. from connector RF A)
      samples_received = s->rx_stream->recv(buff[0], nsamps, s->rx_md);
    }
  }

  if (samples_received < nsamps) {
    printf("[recv] received %d samples out of %d\n",samples_received,nsamps);
    
  }

  //handle the error code
  switch(s->rx_md.error_code){
  case uhd::rx_metadata_t::ERROR_CODE_NONE:
    break;
  case uhd::rx_metadata_t::ERROR_CODE_OVERFLOW:
    printf("[recv] USRP RX OVERFLOW!\n");
    s->num_overflows++;
    break;
  case uhd::rx_metadata_t::ERROR_CODE_TIMEOUT:
    printf("[recv] USRP RX TIMEOUT!\n");
    break;
  default:
    printf("[recv] Unexpected error on RX, Error code: 0x%x\n",s->rx_md.error_code);
    break;
  }
  s->rx_count += nsamps;
  s->rx_timestamp = s->rx_md.time_spec.to_ticks(s->sample_rate);
  *ptimestamp = s->rx_timestamp;

  return samples_received;
}

openair0_timestamp get_usrp_time(openair0_device *device) 
{
 
  usrp_state_t *s = (usrp_state_t*)device->priv;
  
  return s->usrp->get_time_now().to_ticks(s->sample_rate);
} 

static bool is_equal(double a, double b)
{
  return std::fabs(a-b) < std::numeric_limits<double>::epsilon();
}

int trx_usrp_set_freq(openair0_device* device, openair0_config_t *openair0_cfg, int dummy) {

  usrp_state_t *s = (usrp_state_t*)device->priv;

  s->usrp->set_tx_freq(openair0_cfg[0].tx_freq[0]);
  s->usrp->set_rx_freq(openair0_cfg[0].rx_freq[0]);

  return(0);
  
}

int openair0_set_rx_frequencies(openair0_device* device, openair0_config_t *openair0_cfg) {

  usrp_state_t *s = (usrp_state_t*)device->priv;
  static int first_call=1;
  static double rf_freq,diff;

  uhd::tune_request_t rx_tune_req(openair0_cfg[0].rx_freq[0]);

  rx_tune_req.rf_freq_policy = uhd::tune_request_t::POLICY_MANUAL;
  rx_tune_req.rf_freq = openair0_cfg[0].rx_freq[0];
  rf_freq=openair0_cfg[0].rx_freq[0];
  s->usrp->set_rx_freq(rx_tune_req);

  return(0);
  
}

int trx_usrp_set_gains(openair0_device* device, 
		       openair0_config_t *openair0_cfg) {

  usrp_state_t *s = (usrp_state_t*)device->priv;

  s->usrp->set_tx_gain(openair0_cfg[0].tx_gain[0]);
  ::uhd::gain_range_t gain_range = s->usrp->get_rx_gain_range(0);
  // limit to maximum gain
  if (openair0_cfg[0].rx_gain[0]-openair0_cfg[0].rx_gain_offset[0] > gain_range.stop()) {
    
    printf("RX Gain 0 too high, reduce by %f dB\n",
	   openair0_cfg[0].rx_gain[0]-openair0_cfg[0].rx_gain_offset[0] - gain_range.stop());	   
    exit(-1);
  }
  s->usrp->set_rx_gain(openair0_cfg[0].rx_gain[0]-openair0_cfg[0].rx_gain_offset[0]);
  printf("Setting USRP RX gain to %f (rx_gain %f,gain_range.stop() %f)\n", openair0_cfg[0].rx_gain[0]-openair0_cfg[0].rx_gain_offset[0],openair0_cfg[0].rx_gain[0],gain_range.stop());

  return(0);
}

int trx_usrp_stop(int card) {
  return(0);
}


rx_gain_calib_table_t calib_table_b210[] = {
  {3500000000.0,44.0},
  {2660000000.0,49.0},
  {2300000000.0,50.0},
  {1880000000.0,53.0},
  {816000000.0,58.0},
  {-1,0}};

rx_gain_calib_table_t calib_table_b210_38[] = {
  {3500000000.0,44.0},
  {2660000000.0,49.8},
  {2300000000.0,51.0},
  {1880000000.0,53.0},
  {816000000.0,57.0},
  {-1,0}};

rx_gain_calib_table_t calib_table_x310[] = {
  {3500000000.0,77.0},
  {2660000000.0,81.0},
  {2300000000.0,81.0},
  {1880000000.0,82.0},
  {816000000.0,85.0},
  {-1,0}};

void set_rx_gain_offset(openair0_config_t *openair0_cfg, int chain_index,int bw_gain_adjust) {

  int i=0;
  // loop through calibration table to find best adjustment factor for RX frequency
  double min_diff = 6e9,diff,gain_adj=0.0;
  if (bw_gain_adjust==1) {
    switch ((int)openair0_cfg[0].sample_rate) {
    case 30720000:      
      break;
    case 23040000:
      gain_adj=1.25;
      break;
    case 15360000:
      gain_adj=3.0;
      break;
    case 7680000:
      gain_adj=6.0;
      break;
    case 3840000:
      gain_adj=9.0;
      break;
    case 1920000:
      gain_adj=12.0;
      break;
    default:
      printf("unknown sampling rate %d\n",(int)openair0_cfg[0].sample_rate);
      exit(-1);
      break;
    }
  }
  while (openair0_cfg->rx_gain_calib_table[i].freq>0) {
    diff = fabs(openair0_cfg->rx_freq[chain_index] - openair0_cfg->rx_gain_calib_table[i].freq);
    printf("cal %d: freq %f, offset %f, diff %f\n",
	   i,
	   openair0_cfg->rx_gain_calib_table[i].freq,
	   openair0_cfg->rx_gain_calib_table[i].offset,diff);
    if (min_diff > diff) {
      min_diff = diff;
      openair0_cfg->rx_gain_offset[chain_index] = openair0_cfg->rx_gain_calib_table[i].offset+gain_adj;
    }
    i++;
  }
  
}


int trx_usrp_get_stats(openair0_device* device) {

  return(0);

}
int trx_usrp_reset_stats(openair0_device* device) {

  return(0);

}


int openair0_dev_init_usrp(openair0_device* device, openair0_config_t *openair0_cfg)
{
  uhd::set_thread_priority_safe(1.0);
  usrp_state_t *s = (usrp_state_t*)malloc(sizeof(usrp_state_t));
  memset(s, 0, sizeof(usrp_state_t));

  // Initialize USRP device

  std::string args = "type=b200";


  uhd::device_addrs_t device_adds = uhd::device::find(args);
  size_t i;
  
  int vers=0,subvers=0,subsubvers=0;
  int bw_gain_adjust=0;

  sscanf(uhd::get_version_string().c_str(),"%d.%d.%d",&vers,&subvers,&subsubvers);

  printf("Checking for USRPs : UHD %s (%d.%d.%d)\n",uhd::get_version_string().c_str(),vers,subvers,subsubvers);
  
  if(device_adds.size() == 0)
  {
    double usrp_master_clock = 184.32e6;

    std::string args = "type=x300";
    
    // workaround for an api problem, master clock has to be set with the constructor not via set_master_clock_rate
    args += boost::str(boost::format(",master_clock_rate=%f") % usrp_master_clock);
    
    uhd::device_addrs_t device_adds = uhd::device::find(args);

    if(device_adds.size() == 0)
    {
      std::cerr<<"No USRP Device Found. " << std::endl;
      free(s);
      return -1;

    }


    printf("Found USRP X300\n");
    s->usrp = uhd::usrp::multi_usrp::make(args);
    //  s->usrp->set_rx_subdev_spec(rx_subdev);
    //  s->usrp->set_tx_subdev_spec(tx_subdev);

    // lock mboard clocks
    s->usrp->set_clock_source("internal");
    
    //Setting device type to USRP X300/X310 
    device->type=USRP_X300_IF;

    // this is not working yet, master clock has to be set via constructor
    // set master clock rate and sample rate for tx & rx for streaming
    //s->usrp->set_master_clock_rate(usrp_master_clock);

    openair0_cfg[0].rx_gain_calib_table = calib_table_x310;

    switch ((int)openair0_cfg[0].sample_rate) {
    case 30720000:
            // from usrp_time_offset
      openair0_cfg[0].samples_per_packet    = 2048;
      openair0_cfg[0].tx_sample_advance     = 15;
      openair0_cfg[0].tx_bw                 = 20e6;
      openair0_cfg[0].rx_bw                 = 20e6;
      openair0_cfg[0].tx_scheduling_advance = 8*openair0_cfg[0].samples_per_packet;
      break;
    case 15360000:
      openair0_cfg[0].samples_per_packet    = 2048;
      openair0_cfg[0].tx_sample_advance     = 45;
      openair0_cfg[0].tx_bw                 = 10e6;
      openair0_cfg[0].rx_bw                 = 10e6;
      openair0_cfg[0].tx_scheduling_advance = 5*openair0_cfg[0].samples_per_packet;
      break;
    case 7680000:
      openair0_cfg[0].samples_per_packet    = 1024;
      openair0_cfg[0].tx_sample_advance     = 50;
      openair0_cfg[0].tx_bw                 = 5e6;
      openair0_cfg[0].rx_bw                 = 5e6;
      openair0_cfg[0].tx_scheduling_advance = 5*openair0_cfg[0].samples_per_packet;
      break;
    case 1920000:
      openair0_cfg[0].samples_per_packet    = 256;
      openair0_cfg[0].tx_sample_advance     = 50;
      openair0_cfg[0].tx_bw                 = 1.25e6;
      openair0_cfg[0].rx_bw                 = 1.25e6;
      openair0_cfg[0].tx_scheduling_advance = 8*openair0_cfg[0].samples_per_packet;
      break;
    default:
      printf("Error: unknown sampling rate %f\n",openair0_cfg[0].sample_rate);
      exit(-1);
      break;
    }

  } else {
    printf("Found USRP B200");
    s->usrp = uhd::usrp::multi_usrp::make(args);

    //  s->usrp->set_rx_subdev_spec(rx_subdev);
    //  s->usrp->set_tx_subdev_spec(tx_subdev);

// do not explicitly set the clock to "internal", because this will disable the gpsdo
//    // lock mboard clocks
//    s->usrp->set_clock_source("internal");
    // set master clock rate and sample rate for tx & rx for streaming

    device->type = USRP_B200_IF;


    if ((vers == 3) && (subvers == 9) && (subsubvers>=2)) {
      openair0_cfg[0].rx_gain_calib_table = calib_table_b210;
      bw_gain_adjust=0;
    }
    else {
      openair0_cfg[0].rx_gain_calib_table = calib_table_b210_38;
      bw_gain_adjust=1;
    }
    switch ((int)openair0_cfg[0].sample_rate) {
    case 30720000:
      s->usrp->set_master_clock_rate(30.72e6);
            // from usrp_time_offset
      openair0_cfg[0].samples_per_packet    = 4096;
      openair0_cfg[0].tx_sample_advance     = 115;
      openair0_cfg[0].tx_bw                 = 20e6;
      openair0_cfg[0].rx_bw                 = 20e6;
      openair0_cfg[0].tx_scheduling_advance = 11*openair0_cfg[0].samples_per_packet;
      break;
    case 23040000:
      s->usrp->set_master_clock_rate(46.08e6);
      openair0_cfg[0].samples_per_packet    = 2048;
      openair0_cfg[0].tx_sample_advance     = 113;
      openair0_cfg[0].tx_bw                 = 20e6;
      openair0_cfg[0].rx_bw                 = 20e6;
      openair0_cfg[0].tx_scheduling_advance = 8*openair0_cfg[0].samples_per_packet;
      break;
    case 15360000:
      s->usrp->set_master_clock_rate(30.72e6);
      openair0_cfg[0].samples_per_packet    = 2048;
      openair0_cfg[0].tx_sample_advance     = 113;
      openair0_cfg[0].tx_bw                 = 10e6;
      openair0_cfg[0].rx_bw                 = 10e6;
      openair0_cfg[0].tx_scheduling_advance = 5*openair0_cfg[0].samples_per_packet;
      break;
    case 7680000:
      s->usrp->set_master_clock_rate(30.72e6);
      openair0_cfg[0].samples_per_packet    = 1024;
      openair0_cfg[0].tx_sample_advance     = 70;//103;
      openair0_cfg[0].tx_bw                 = 5e6;
      openair0_cfg[0].rx_bw                 = 5e6;
      openair0_cfg[0].tx_scheduling_advance = 5*openair0_cfg[0].samples_per_packet;
      break;
    case 1920000:
      s->usrp->set_master_clock_rate(30.72e6);
      openair0_cfg[0].samples_per_packet    = 256;
      openair0_cfg[0].tx_sample_advance     = 40;
      openair0_cfg[0].tx_bw                 = 1.25e6;
      openair0_cfg[0].rx_bw                 = 1.25e6;
      openair0_cfg[0].tx_scheduling_advance = 8*openair0_cfg[0].samples_per_packet;
      break;
    default:
      printf("Error: unknown sampling rate %f\n",openair0_cfg[0].sample_rate);
      exit(-1);
      break;
    }
  }

  for(i=0;i<s->usrp->get_rx_num_channels();i++) {
    if (i<openair0_cfg[0].rx_num_channels) {
      s->usrp->set_rx_rate(openair0_cfg[0].sample_rate,i);
      s->usrp->set_rx_bandwidth(openair0_cfg[0].rx_bw,i);
      printf("Setting rx freq/gain on channel %lu/%lu : BW %f (readback %f)\n",i,s->usrp->get_rx_num_channels(),openair0_cfg[0].rx_bw/1e6,s->usrp->get_rx_bandwidth(i)/1e6);
      s->usrp->set_rx_freq(openair0_cfg[0].rx_freq[i],i);
      set_rx_gain_offset(&openair0_cfg[0],i,bw_gain_adjust);

      ::uhd::gain_range_t gain_range = s->usrp->get_rx_gain_range(i);
      // limit to maximum gain
      if (openair0_cfg[0].rx_gain[i]-openair0_cfg[0].rx_gain_offset[i] > gain_range.stop()) {
	
        printf("RX Gain %lu too high, lower by %f dB\n",i,openair0_cfg[0].rx_gain[i]-openair0_cfg[0].rx_gain_offset[i] - gain_range.stop());
	exit(-1);
      }
      s->usrp->set_rx_gain(openair0_cfg[0].rx_gain[i]-openair0_cfg[0].rx_gain_offset[i],i);
      printf("RX Gain %lu %f (%f) => %f (max %f)\n",i,
	     openair0_cfg[0].rx_gain[i],openair0_cfg[0].rx_gain_offset[i],
	     openair0_cfg[0].rx_gain[i]-openair0_cfg[0].rx_gain_offset[i],gain_range.stop());
    }
  }
  for(i=0;i<s->usrp->get_tx_num_channels();i++) {
    if (i<openair0_cfg[0].tx_num_channels) {
      s->usrp->set_tx_rate(openair0_cfg[0].sample_rate,i);
      s->usrp->set_tx_bandwidth(openair0_cfg[0].tx_bw,i);
      printf("Setting tx freq/gain on channel %lu/%lu: BW %f (readback %f)\n",i,s->usrp->get_tx_num_channels(),openair0_cfg[0].tx_bw/1e6,s->usrp->get_tx_bandwidth(i)/1e6);
      s->usrp->set_tx_freq(openair0_cfg[0].tx_freq[i],i);
      s->usrp->set_tx_gain(openair0_cfg[0].tx_gain[i],i);
    }
  }


  // display USRP settings
  std::cout << boost::format("Actual master clock: %fMHz...") % (s->usrp->get_master_clock_rate()/1e6) << std::endl;

  // create tx & rx streamer
  uhd::stream_args_t stream_args_rx("sc16", "sc16");
  //stream_args_rx.args["spp"] = str(boost::format("%d") % 2048);//(openair0_cfg[0].rx_num_channels*openair0_cfg[0].samples_per_packet));
  for (i = 0; i<openair0_cfg[0].rx_num_channels; i++)
    stream_args_rx.channels.push_back(i);
  s->rx_stream = s->usrp->get_rx_stream(stream_args_rx);
  std::cout << boost::format("rx_max_num_samps %u") % (s->rx_stream->get_max_num_samps()) << std::endl;
  //openair0_cfg[0].samples_per_packet = s->rx_stream->get_max_num_samps();

  uhd::stream_args_t stream_args_tx("sc16", "sc16");
  //stream_args_tx.args["spp"] = str(boost::format("%d") % 2048);//(openair0_cfg[0].tx_num_channels*openair0_cfg[0].samples_per_packet));
  for (i = 0; i<openair0_cfg[0].tx_num_channels; i++)
      stream_args_tx.channels.push_back(i);
  s->tx_stream = s->usrp->get_tx_stream(stream_args_tx);
  std::cout << boost::format("tx_max_num_samps %u") % (s->tx_stream->get_max_num_samps()) << std::endl;


  s->usrp->set_time_now(uhd::time_spec_t(0.0));



  

  for (i=0;i<openair0_cfg[0].rx_num_channels;i++) {
    if (i<openair0_cfg[0].rx_num_channels) {
      printf("RX Channel %lu\n",i);
      std::cout << boost::format("Actual RX sample rate: %fMSps...") % (s->usrp->get_rx_rate(i)/1e6) << std::endl;
      std::cout << boost::format("Actual RX frequency: %fGHz...") % (s->usrp->get_rx_freq(i)/1e9) << std::endl;
      std::cout << boost::format("Actual RX gain: %f...") % (s->usrp->get_rx_gain(i)) << std::endl;
      std::cout << boost::format("Actual RX bandwidth: %fM...") % (s->usrp->get_rx_bandwidth(i)/1e6) << std::endl;
      std::cout << boost::format("Actual RX antenna: %s...") % (s->usrp->get_rx_antenna(i)) << std::endl;
    }
  }

  for (i=0;i<openair0_cfg[0].tx_num_channels;i++) {

    if (i<openair0_cfg[0].tx_num_channels) { 
      printf("TX Channel %lu\n",i);
      std::cout << std::endl<<boost::format("Actual TX sample rate: %fMSps...") % (s->usrp->get_tx_rate(i)/1e6) << std::endl;
      std::cout << boost::format("Actual TX frequency: %fGHz...") % (s->usrp->get_tx_freq(i)/1e9) << std::endl;
      std::cout << boost::format("Actual TX gain: %f...") % (s->usrp->get_tx_gain(i)) << std::endl;
      std::cout << boost::format("Actual TX bandwidth: %fM...") % (s->usrp->get_tx_bandwidth(i)/1e6) << std::endl;
      std::cout << boost::format("Actual TX antenna: %s...") % (s->usrp->get_tx_antenna(i)) << std::endl;
    }
  }

  std::cout << boost::format("Device timestamp: %f...") % (s->usrp->get_time_now().get_real_secs()) << std::endl;

  device->priv = s;
  device->trx_start_func = trx_usrp_start;
  device->trx_write_func = trx_usrp_write;
  device->trx_read_func  = trx_usrp_read;
  device->trx_get_stats_func = trx_usrp_get_stats;
  device->trx_reset_stats_func = trx_usrp_reset_stats;
  device->trx_end_func   = trx_usrp_end;
  device->trx_stop_func  = trx_usrp_stop;
  device->trx_set_freq_func = trx_usrp_set_freq;
  device->trx_set_gains_func   = trx_usrp_set_gains;
  
  s->sample_rate = openair0_cfg[0].sample_rate;
  // TODO:
  // init tx_forward_nsamps based usrp_time_offset ex
  if(is_equal(s->sample_rate, (double)30.72e6))
    s->tx_forward_nsamps  = 176;
  if(is_equal(s->sample_rate, (double)15.36e6))
    s->tx_forward_nsamps = 90;
  if(is_equal(s->sample_rate, (double)7.68e6))
    s->tx_forward_nsamps = 50;
  return 0;
}