New generic transmit power handling

In order to support transmit power reduction by thermal management
as well as the variety of new internal / external PA configurations
of BTSs, we need a slightly more complex system.

Also, as at high power a single dB can be quite a big difference,
we are now doing all computations in milli-dB(m), i.e. 1/10000 bel.

Ramping is now used both for up and down ramping, as that is useful in
cases where you want to gracefully shut down a cell by shrinking its
radius, gradually handing over subscribers to neighboring cells.

Furthermore, this code is becoming part of the 'common' codebase, as it
is not really specific to how sysmobts is working.

The user can specify a single aggregate value for external system
gain/attenuation.  Let's say you have 1dB loss of antenna cable, so you
can put that as 'user-gain -1' into the config, which means that a
'transmit power of 20dBm' will be compensatet for that and the TRX is
instructed to output 21dBm to compensate the cable loss.  Similarly,
external PAs can be described by a positive user-gain.

One of the next steps will be to communicate those values and the
nominal power capability of the specific BTS to the BSC, so the BSC will
automatically show correct signal levels in the VTY and log files.

The code includes provisions for future extensions regarding
* an external and an internal PA with calibration tables
* a thermal attenuation setting to be controlled by the site manager

1 files changed, 82 insertions, 0 deletions

diff --git a/src/common/vty.c b/src/common/vty.c
index ea38ac95..a2f2fb37 100644
--- a/src/common/vty.c
+++ b/src/common/vty.c
@@ -186,7 +186,19 @@ static void config_write_bts_single(struct vty *vty, struct gsm_bts *bts)
 	bts_model_config_write_bts(vty, bts);
 
 	llist_for_each_entry(trx, &bts->trx_list, list) {
+		struct trx_power_params *tpp = &trx->power_params;
 		vty_out(vty, " trx %u%s", trx->nr, VTY_NEWLINE);
+
+		if (trx->power_params.user_gain_mdB)
+			vty_out(vty, "  user-gain %u mdB%s",
+				tpp->user_gain_mdB, VTY_NEWLINE);
+		vty_out(vty, "  power-ramp max-initinal-pout %d mdBm%s",
+			tpp->ramp.max_initial_pout_mdBm, VTY_NEWLINE);
+		vty_out(vty, "  power-ramp step-size %d mdBm%s",
+			tpp->ramp.step_size_mdB, VTY_NEWLINE);
+		vty_out(vty, "  power-ramp step-interval %d%s",
+			tpp->ramp.step_interval_sec, VTY_NEWLINE);
+
 		bts_model_config_write_trx(vty, trx);
 	}
 }
@@ -384,6 +396,71 @@ DEFUN(cfg_bts_agch_queue_mgmt_default,
 	return CMD_SUCCESS;
 }
 
+#define DB_DBM_STR 							\
+	"Unit is dB (decibels)\n"					\
+	"Unit is mdB (milli-decibels, or rather 1/10000 bel)\n"
+
+static int parse_mdbm(const char *valstr, const char *unit)
+{
+	int val = atoi(valstr);
+
+	if (!strcmp(unit, "dB") || !strcmp(unit, "dBm"))
+		return val * 1000;
+	else
+		return val;
+}
+
+DEFUN(cfg_trx_user_gain,
+	cfg_trx_user_gain_cmd,
+	"user-gain <-100000-100000> (dB|mdB)",
+	"Inform BTS about additional, user-provided gain or attenuation at TRX output\n"
+	"Value of user-provided external gain(+)/attenuation(-)\n" DB_DBM_STR)
+{
+	struct gsm_bts_trx *trx = vty->index;
+
+	trx->power_params.user_gain_mdB = parse_mdbm(argv[0], argv[1]);
+
+	return CMD_SUCCESS;
+}
+
+#define PR_STR "Power-Ramp settings"
+DEFUN(cfg_trx_pr_max_initial, cfg_trx_pr_max_initial_cmd,
+	"power-ramp max-initial <0-100000> (dBm|mdBm)",
+	PR_STR "Maximum initial power\n"
+	"Value\n" DB_DBM_STR)
+{
+	struct gsm_bts_trx *trx = vty->index;
+
+	trx->power_params.ramp.max_initial_pout_mdBm =
+				parse_mdbm(argv[0], argv[1]);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_trx_pr_step_size, cfg_trx_pr_step_size_cmd,
+	"power-ramp step-size <1-100000> (dB|mdB)",
+	PR_STR "Power increase by step\n"
+	"Step size\n" DB_DBM_STR)
+{
+	struct gsm_bts_trx *trx = vty->index;
+
+	trx->power_params.ramp.step_size_mdB =
+				parse_mdbm(argv[0], argv[1]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_trx_pr_step_interval, cfg_trx_pr_step_interval_cmd,
+	"power-ramp step-interval <1-100>",
+	PR_STR "Power increase by step\n"
+	"Step time in seconds\n")
+{
+	struct gsm_bts_trx *trx = vty->index;
+
+	trx->power_params.ramp.step_interval_sec = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+
+
 
 /* ======================================================================
  * SHOW
@@ -563,6 +640,11 @@ int bts_vty_init(const struct log_info *cat)
 	install_node(&trx_node, config_write_dummy);
 	install_default(TRX_NODE);
 
+	install_element(TRX_NODE, &cfg_trx_user_gain_cmd);
+	install_element(TRX_NODE, &cfg_trx_pr_max_initial_cmd);
+	install_element(TRX_NODE, &cfg_trx_pr_step_size_cmd);
+	install_element(TRX_NODE, &cfg_trx_pr_step_interval_cmd);
+
 	install_element(ENABLE_NODE, &bts_t_t_l_jitter_buf_cmd);
 
 	return 0;