trxcon/scheduler: refactor Downlink measurement processing

So far we used to store the sums of ToA and RSSI measurements in the
logical channel state, and after decoding of a block, we did calculate
the average. This approach works fine for xCCH and PDTCH, but when it
comes to block-diagonal interleaving (which is used on TCH/F and TCH/H
channels), the results are incorrect. The problem is that a burst on
TCH may carry 57 bits of one encoded frame and 57 bits of another.

Instead of calculating the sum of measurements on the fly, let's push
them into a circular buffer (the measurement history), and keep them
there even after decoding of a block. This would allow us to calculate
the average of N last measurements depending on the interleaving type.

A single circular buffer can hold up to 8 unique measurements, so the
recent measurements would basically override the oldest ones.

Change-Id: I211ee3314f0a284112a4deddc0e93028f4a27cef
changes/50/17350/4
Vadim Yanitskiy 3 years ago committed by laforge
parent d534d43fc1
commit 2060b5b7cc
  1. 15
      src/host/trxcon/sched_lchan_common.c
  2. 10
      src/host/trxcon/sched_lchan_desc.c
  3. 16
      src/host/trxcon/sched_lchan_pdtch.c
  4. 4
      src/host/trxcon/sched_lchan_sch.c
  5. 25
      src/host/trxcon/sched_lchan_tchf.c
  6. 34
      src/host/trxcon/sched_lchan_tchh.c
  7. 16
      src/host/trxcon/sched_lchan_xcch.c
  8. 51
      src/host/trxcon/sched_trx.c
  9. 34
      src/host/trxcon/sched_trx.h
  10. 9
      src/host/trxcon/trx_if.c

@ -126,9 +126,9 @@ int sched_send_dt_ind(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint8_t *l2, size_t l2_len,
int bit_error_count, bool dec_failed, bool traffic)
{
const struct trx_meas_set *meas = &lchan->meas_avg;
const struct trx_lchan_desc *lchan_desc;
struct l1ctl_info_dl dl_hdr;
int dbm_avg = 0;
/* Set up pointers */
lchan_desc = &trx_lchan_desc[lchan->type];
@ -140,15 +140,8 @@ int sched_send_dt_ind(struct trx_instance *trx, struct trx_ts *ts,
dl_hdr.frame_nr = htonl(lchan->rx_first_fn);
dl_hdr.num_biterr = bit_error_count;
/* Convert average RSSI to RX level */
if (lchan->meas.num) {
/* RX level: 0 .. 63 in typical GSM notation (dBm + 110) */
dbm_avg = lchan->meas.rssi_sum / lchan->meas.num;
dl_hdr.rx_level = dbm2rxlev(dbm_avg);
} else {
/* No measurements, assuming the worst */
dl_hdr.rx_level = 0;
}
/* RX level: 0 .. 63 in typical GSM notation (dBm + 110) */
dl_hdr.rx_level = dbm2rxlev(meas->rssi);
/* FIXME: set proper values */
dl_hdr.snr = 0;
@ -162,7 +155,7 @@ int sched_send_dt_ind(struct trx_instance *trx, struct trx_ts *ts,
/* Optional GSMTAP logging */
if (l2_len > 0 && (!traffic || lchan_desc->chan_nr == RSL_CHAN_OSMO_PDCH)) {
sched_gsmtap_send(lchan->type, lchan->rx_first_fn, ts->index,
trx->band_arfcn, dbm_avg, 0, l2, l2_len);
trx->band_arfcn, meas->rssi, 0, l2, l2_len);
}
return 0;

@ -31,35 +31,35 @@
/* Forward declaration of handlers */
int rx_data_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256);
sbit_t *bits, const struct trx_meas_set *meas);
int tx_data_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid);
int rx_sch_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256);
sbit_t *bits, const struct trx_meas_set *meas);
int tx_rach_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid);
int rx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256);
sbit_t *bits, const struct trx_meas_set *meas);
int tx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid);
int rx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256);
sbit_t *bits, const struct trx_meas_set *meas);
int tx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid);
int rx_pdtch_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256);
sbit_t *bits, const struct trx_meas_set *meas);
int tx_pdtch_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid);

@ -2,7 +2,7 @@
* OsmocomBB <-> SDR connection bridge
* TDMA scheduler: handlers for DL / UL bursts on logical channels
*
* (C) 2018 by Vadim Yanitskiy <axilirator@gmail.com>
* (C) 2018-2020 by Vadim Yanitskiy <axilirator@gmail.com>
*
* All Rights Reserved
*
@ -42,7 +42,7 @@
int rx_pdtch_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256)
sbit_t *bits, const struct trx_meas_set *meas)
{
const struct trx_lchan_desc *lchan_desc;
uint8_t l2[GPRS_L2_MAX_LEN], *mask;
@ -62,9 +62,6 @@ int rx_pdtch_fn(struct trx_instance *trx, struct trx_ts *ts,
/* Reset internal state */
if (bid == 0) {
/* Clean up old measurements */
memset(&lchan->meas, 0x00, sizeof(lchan->meas));
*first_fn = fn;
*mask = 0x0;
}
@ -72,10 +69,8 @@ int rx_pdtch_fn(struct trx_instance *trx, struct trx_ts *ts,
/* Update mask */
*mask |= (1 << bid);
/* Update measurements */
lchan->meas.toa256_sum += toa256;
lchan->meas.rssi_sum += rssi;
lchan->meas.num++;
/* Store the measurements */
sched_trx_meas_push(lchan, meas);
/* Copy burst to buffer of 4 bursts */
offset = buffer + bid * 116;
@ -86,6 +81,9 @@ int rx_pdtch_fn(struct trx_instance *trx, struct trx_ts *ts,
if (bid != 3)
return 0;
/* Calculate AVG of the measurements */
sched_trx_meas_avg(lchan, 4);
/* Check for complete set of bursts */
if ((*mask & 0xf) != 0xf) {
LOGP(DSCHD, LOGL_ERROR, "Received incomplete (%s) data frame at "

@ -70,7 +70,7 @@ static void decode_sb(struct gsm_time *time, uint8_t *bsic, uint8_t *sb_info)
int rx_sch_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256)
sbit_t *bits, const struct trx_meas_set *meas)
{
sbit_t payload[2 * 39];
struct gsm_time time;
@ -117,7 +117,7 @@ int rx_sch_fn(struct trx_instance *trx, struct trx_ts *ts,
data->link_id = trx_lchan_desc[lchan->type].link_id;
data->band_arfcn = htons(trx->band_arfcn);
data->frame_nr = htonl(fn);
data->rx_level = -rssi;
data->rx_level = -(meas->rssi);
/* FIXME: set proper values */
data->num_biterr = 0;

@ -2,7 +2,7 @@
* OsmocomBB <-> SDR connection bridge
* TDMA scheduler: handlers for DL / UL bursts on logical channels
*
* (C) 2017 by Vadim Yanitskiy <axilirator@gmail.com>
* (C) 2017-2020 by Vadim Yanitskiy <axilirator@gmail.com>
*
* All Rights Reserved
*
@ -44,7 +44,7 @@
int rx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256)
sbit_t *bits, const struct trx_meas_set *meas)
{
const struct trx_lchan_desc *lchan_desc;
int n_errors = -1, n_bits_total, rc;
@ -64,9 +64,6 @@ int rx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
/* Reset internal state */
if (bid == 0) {
/* Clean up old measurements */
memset(&lchan->meas, 0x00, sizeof(lchan->meas));
*first_fn = fn;
*mask = 0x00;
}
@ -74,10 +71,8 @@ int rx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
/* Update mask */
*mask |= (1 << bid);
/* Update mask and RSSI */
lchan->meas.rssi_sum += rssi;
lchan->meas.toa256_sum += toa256;
lchan->meas.num++;
/* Store the measurements */
sched_trx_meas_push(lchan, meas);
/* Copy burst to end of buffer of 8 bursts */
offset = buffer + bid * 116 + 464;
@ -88,6 +83,9 @@ int rx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
if (bid != 3)
return 0;
/* Calculate AVG of the measurements */
sched_trx_meas_avg(lchan, 8);
/* Check for complete set of bursts */
if ((*mask & 0xf) != 0xf) {
LOGP(DSCHD, LOGL_ERROR, "Received incomplete (%s) traffic frame at "
@ -150,9 +148,14 @@ int rx_tchf_fn(struct trx_instance *trx, struct trx_ts *ts,
n_errors, false, true);
bfi:
/* Didn't try to decode */
if (n_errors < 0)
/* Didn't try to decode, fake measurements */
if (n_errors < 0) {
lchan->meas_avg = (struct trx_meas_set) {
.toa256 = 0,
.rssi = -110,
};
n_errors = 116 * 4;
}
/* BFI is not applicable in signalling mode */
if (lchan->tch_mode == GSM48_CMODE_SIGN)

@ -2,7 +2,7 @@
* OsmocomBB <-> SDR connection bridge
* TDMA scheduler: handlers for DL / UL bursts on logical channels
*
* (C) 2018 by Vadim Yanitskiy <axilirator@gmail.com>
* (C) 2018-2020 by Vadim Yanitskiy <axilirator@gmail.com>
* (C) 2018 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
@ -200,7 +200,7 @@ uint32_t sched_tchh_block_dl_first_fn(enum trx_lchan_type chan,
int rx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256)
sbit_t *bits, const struct trx_meas_set *meas)
{
const struct trx_lchan_desc *lchan_desc;
int n_errors = -1, n_bits_total, rc;
@ -234,16 +234,8 @@ int rx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts,
/* Update mask */
*mask |= (1 << bid);
/**
* FIXME: properly update measurements
*
* Since TCH/H channel is using block-diagonal interleaving,
* a single burst may carry 57 bits of one encoded frame,
* and 57 bits of another. This should be taken into account.
*/
lchan->meas.rssi_sum += rssi;
lchan->meas.toa256_sum += toa256;
lchan->meas.num++;
/* Store the measurements */
sched_trx_meas_push(lchan, meas);
/* Copy burst to the end of buffer of 6 bursts */
offset = buffer + bid * 116 + 464;
@ -303,6 +295,9 @@ int rx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts,
"fn=%u on %s (rc=%d)\n", burst_mask2str(mask, 6),
fn, lchan_desc->name, rc);
/* Calculate AVG of the measurements (assuming 4 bursts) */
sched_trx_meas_avg(lchan, 4);
/* Send BFI */
goto bfi;
} else if (rc == GSM_MACBLOCK_LEN) {
@ -313,6 +308,9 @@ int rx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts,
lchan->rx_first_fn = sched_tchh_block_dl_first_fn(lchan->type,
fn, true); /* FACCH/H */
/* Calculate AVG of the measurements (FACCH/H takes 6 bursts) */
sched_trx_meas_avg(lchan, 6);
/* FACCH/H received, forward to the higher layers */
sched_send_dt_ind(trx, ts, lchan, l2, GSM_MACBLOCK_LEN,
n_errors, false, false);
@ -322,6 +320,9 @@ int rx_tchh_fn(struct trx_instance *trx, struct trx_ts *ts,
} else {
/* A good TCH frame received */
l2_len = rc;
/* Calculate AVG of the measurements (traffic takes 4 bursts) */
sched_trx_meas_avg(lchan, 4);
}
/* Calculate TDMA frame number of the first burst */
@ -341,9 +342,14 @@ bfi_shift:
*mask = *mask << 2;
bfi:
/* Didn't try to decode */
if (n_errors < 0)
/* Didn't try to decode, fake measurements */
if (n_errors < 0) {
lchan->meas_avg = (struct trx_meas_set) {
.toa256 = 0,
.rssi = -110,
};
n_errors = 116 * 2;
}
/* Calculate TDMA frame number of the first burst */
lchan->rx_first_fn = sched_tchh_block_dl_first_fn(lchan->type,

@ -2,7 +2,7 @@
* OsmocomBB <-> SDR connection bridge
* TDMA scheduler: handlers for DL / UL bursts on logical channels
*
* (C) 2017 by Vadim Yanitskiy <axilirator@gmail.com>
* (C) 2017-2020 by Vadim Yanitskiy <axilirator@gmail.com>
*
* All Rights Reserved
*
@ -42,7 +42,7 @@
int rx_data_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256)
sbit_t *bits, const struct trx_meas_set *meas)
{
const struct trx_lchan_desc *lchan_desc;
uint8_t l2[GSM_MACBLOCK_LEN], *mask;
@ -61,9 +61,6 @@ int rx_data_fn(struct trx_instance *trx, struct trx_ts *ts,
/* Reset internal state */
if (bid == 0) {
/* Clean up old measurements */
memset(&lchan->meas, 0x00, sizeof(lchan->meas));
*first_fn = fn;
*mask = 0x0;
}
@ -71,10 +68,8 @@ int rx_data_fn(struct trx_instance *trx, struct trx_ts *ts,
/* Update mask */
*mask |= (1 << bid);
/* Update measurements */
lchan->meas.rssi_sum += rssi;
lchan->meas.toa256_sum += toa256;
lchan->meas.num++;
/* Store the measurements */
sched_trx_meas_push(lchan, meas);
/* Copy burst to buffer of 4 bursts */
offset = buffer + bid * 116;
@ -85,6 +80,9 @@ int rx_data_fn(struct trx_instance *trx, struct trx_ts *ts,
if (bid != 3)
return 0;
/* Calculate AVG of the measurements */
sched_trx_meas_avg(lchan, 4);
/* Check for complete set of bursts */
if ((*mask & 0xf) != 0xf) {
LOGP(DSCHD, LOGL_ERROR, "Received incomplete (%s) data frame at "

@ -613,7 +613,7 @@ static void sched_trx_a5_burst_enc(struct trx_lchan_state *lchan,
int sched_trx_handle_rx_burst(struct trx_instance *trx, uint8_t tn,
uint32_t burst_fn, sbit_t *bits, uint16_t nbits,
int8_t rssi, int16_t toa256)
const struct trx_meas_set *meas)
{
struct trx_lchan_state *lchan;
const struct trx_frame *frame;
@ -674,7 +674,7 @@ int sched_trx_handle_rx_burst(struct trx_instance *trx, uint8_t tn,
sched_trx_a5_burst_dec(lchan, fn, bits);
/* Put burst to handler */
handler(trx, ts, lchan, fn, bid, bits, rssi, toa256);
handler(trx, ts, lchan, fn, bid, bits, meas);
}
next_frame:
@ -710,3 +710,50 @@ int sched_trx_handle_tx_burst(struct trx_instance *trx,
return 0;
}
#define MEAS_HIST_FIRST(hist) \
(&hist->buf[0])
#define MEAS_HIST_LAST(hist) \
(MEAS_HIST_FIRST(hist) + ARRAY_SIZE(hist->buf) - 1)
/* Add a new set of measurements to the history */
void sched_trx_meas_push(struct trx_lchan_state *lchan, const struct trx_meas_set *meas)
{
struct trx_lchan_meas_hist *hist = &lchan->meas_hist;
/* Find a new position where to store the measurements */
if (hist->head == MEAS_HIST_LAST(hist) || hist->head == NULL)
hist->head = MEAS_HIST_FIRST(hist);
else
hist->head++;
*hist->head = *meas;
}
/* Calculate the AVG of n measurements from the history */
void sched_trx_meas_avg(struct trx_lchan_state *lchan, unsigned int n)
{
struct trx_lchan_meas_hist *hist = &lchan->meas_hist;
struct trx_meas_set *meas = hist->head;
int toa256_sum = 0;
int rssi_sum = 0;
int i;
OSMO_ASSERT(n > 0 && n <= ARRAY_SIZE(hist->buf));
OSMO_ASSERT(meas != NULL);
/* Traverse backwards up to n entries, calculate the sum */
for (i = 0; i < n; i++) {
toa256_sum += meas->toa256;
rssi_sum += meas->rssi;
if (meas == MEAS_HIST_FIRST(hist))
meas = MEAS_HIST_LAST(hist);
else
meas--;
}
/* Calculate the AVG */
lchan->meas_avg.toa256 = toa256_sum / n;
lchan->meas_avg.rssi = rssi_sum / n;
}

@ -40,6 +40,7 @@
/* Forward declaration to avoid mutual include */
struct trx_lchan_state;
struct trx_meas_set;
struct trx_instance;
struct trx_ts;
@ -99,7 +100,7 @@ enum trx_lchan_type {
typedef int trx_lchan_rx_func(struct trx_instance *trx,
struct trx_ts *ts, struct trx_lchan_state *lchan,
uint32_t fn, uint8_t bid, sbit_t *bits,
int8_t rssi, int16_t toa256);
const struct trx_meas_set *meas);
typedef int trx_lchan_tx_func(struct trx_instance *trx,
struct trx_ts *ts, struct trx_lchan_state *lchan,
@ -157,6 +158,19 @@ struct trx_multiframe {
const struct trx_frame *frames;
};
struct trx_meas_set {
/*! \brief ToA256 (Timing of Arrival, 1/256 of a symbol) */
int16_t toa256;
/*! \brief RSSI (Received Signal Strength Indication) */
int8_t rssi;
};
/* Simple ring buffer (up to 8 unique measurements) */
struct trx_lchan_meas_hist {
struct trx_meas_set buf[8];
struct trx_meas_set *head;
};
/* States each channel on a multiframe */
struct trx_lchan_state {
/*! \brief Channel type */
@ -190,14 +204,10 @@ struct trx_lchan_state {
/*! \brief pending FACCH/H blocks on Uplink */
uint8_t ul_facch_blocks;
struct {
/*! \brief Number of measurements */
unsigned int num;
/*! \brief Sum of RSSI values */
float rssi_sum;
/*! \brief Sum of TOA values */
int32_t toa256_sum;
} meas;
/*! \brief Downlink measurements history */
struct trx_lchan_meas_hist meas_hist;
/*! \brief AVG measurements of the last received block */
struct trx_meas_set meas_avg;
/*! \brief SACCH state */
struct {
@ -347,7 +357,7 @@ void sched_prim_flush_queue(struct llist_head *list);
int sched_trx_handle_rx_burst(struct trx_instance *trx, uint8_t tn,
uint32_t burst_fn, sbit_t *bits, uint16_t nbits,
int8_t rssi, int16_t toa256);
const struct trx_meas_set *meas);
int sched_trx_handle_tx_burst(struct trx_instance *trx,
struct trx_ts *ts, struct trx_lchan_state *lchan,
uint32_t fn, ubit_t *bits);
@ -381,3 +391,7 @@ bool sched_tchh_block_map_fn(enum trx_lchan_type chan,
sched_tchh_block_map_fn(chan, fn, ul, 1, 1)
#define sched_tchh_facch_end(chan, fn, ul) \
sched_tchh_block_map_fn(chan, fn, ul, 1, 0)
/* Measurement history */
void sched_trx_meas_push(struct trx_lchan_state *lchan, const struct trx_meas_set *meas);
void sched_trx_meas_avg(struct trx_lchan_state *lchan, unsigned int n);

@ -555,6 +555,7 @@ rsp_error:
static int trx_data_rx_cb(struct osmo_fd *ofd, unsigned int what)
{
struct trx_instance *trx = ofd->data;
struct trx_meas_set meas;
uint8_t buf[256];
sbit_t bits[148];
int8_t rssi, tn;
@ -595,8 +596,14 @@ static int trx_data_rx_cb(struct osmo_fd *ofd, unsigned int what)
LOGP(DTRXD, LOGL_DEBUG, "RX burst tn=%u fn=%u rssi=%d toa=%d\n",
tn, fn, rssi, toa256);
/* Group the measurements together */
meas = (struct trx_meas_set) {
.toa256 = toa256,
.rssi = rssi,
};
/* Poke scheduler */
sched_trx_handle_rx_burst(trx, tn, fn, bits, 148, rssi, toa256);
sched_trx_handle_rx_burst(trx, tn, fn, bits, 148, &meas);
/* Correct local clock counter */
if (fn % 51 == 0)

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