ms: Add UL CS selection based on L1 link quality

Currently the UL CS values are set to the corresponding DL CS value,
eventually limited by a maximum value. This approach does not reflect
the general situation of the RF link between ME and BTS, which is
rather asymmetric e.g. due to a lower degree of TX efficiency of the
built-in antenna. This means, that UL and DL CS control should be
decoupled for better results.

This commit adds automatic UL CS selection based on the link quality
measurement parameter. Each coding scheme is mapped to a link quality
range. If the link quality value leaves that range, the current UL CS
value is increased/decreased accordingly. This value will be copied
when the next PACKET_UPLINK_ACK_NACK or PACKET_UPLINK_ASSIGMENT is
sent to the MS.

The following VTY command will be added to the config-pcu node:

-  cs link-quality-ranges cs1 <0-35> cs2 <0-35> <0-35>
          cs3 <0-35> <0-35> cs4 <0-35>

which sets the ranges for the four coding schemes. For instance the
example below reflects the current default values:

  cs link-quality-ranges cs1 6 cs2 5 8 cs3 7 13 cs4 12

set the following ranges, where the overlapping is used to configure
a hysteresis:

  CS1: -inf ..  6
  CS2:    5 ..  8
  CS3:    7 .. 13
  CS4:   12 .. inf

Sponsored-by: On-Waves ehf

1 files changed, 45 insertions, 0 deletions

diff --git a/src/pcu_vty.c b/src/pcu_vty.c
index 355f5440..8db025e6 100644
--- a/src/pcu_vty.c
+++ b/src/pcu_vty.c
@@ -90,6 +90,15 @@ static int config_write_pcu(struct vty *vty)
 	else
 		vty_out(vty, " no cs threshold%s", VTY_NEWLINE);
 
+	vty_out(vty, " cs link-quality-ranges cs1 %d cs2 %d %d cs3 %d %d cs4 %d%s",
+		bts->cs_lqual_ranges[0].high,
+		bts->cs_lqual_ranges[1].low,
+		bts->cs_lqual_ranges[1].high,
+		bts->cs_lqual_ranges[2].low,
+		bts->cs_lqual_ranges[2].high,
+		bts->cs_lqual_ranges[3].low,
+		VTY_NEWLINE);
+
 	if (bts->force_llc_lifetime == 0xffff)
 		vty_out(vty, " queue lifetime infinite%s", VTY_NEWLINE);
 	else if (bts->force_llc_lifetime)
@@ -600,6 +609,41 @@ DEFUN(cfg_pcu_no_cs_err_limits,
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_pcu_cs_lqual_ranges,
+      cfg_pcu_cs_lqual_ranges_cmd,
+      "cs link-quality-ranges cs1 <0-35> cs2 <0-35> <0-35> cs3 <0-35> <0-35> cs4 <0-35>",
+      CS_STR "Set link quality ranges\n"
+      "Set quality range for CS-1 (high value only)\n"
+      "CS-1 high (dB)\n"
+      "Set quality range for CS-2\n"
+      "CS-2 low (dB)\n"
+      "CS-2 high (dB)\n"
+      "Set quality range for CS-3\n"
+      "CS-3 low (dB)\n"
+      "CS-3 high (dB)\n"
+      "Set quality range for CS-4 (low value only)\n"
+      "CS-4 low (dB)\n")
+{
+	struct gprs_rlcmac_bts *bts = bts_main_data();
+
+	uint8_t cs1_high = atoi(argv[0]);
+	uint8_t cs2_low = atoi(argv[1]);
+	uint8_t cs2_high = atoi(argv[2]);
+	uint8_t cs3_low = atoi(argv[3]);
+	uint8_t cs3_high = atoi(argv[4]);
+	uint8_t cs4_low = atoi(argv[5]);
+
+	bts->cs_lqual_ranges[0].high = cs1_high;
+	bts->cs_lqual_ranges[1].low  = cs2_low;
+	bts->cs_lqual_ranges[1].high = cs2_high;
+	bts->cs_lqual_ranges[2].low  = cs3_low;
+	bts->cs_lqual_ranges[2].high = cs3_high;
+	bts->cs_lqual_ranges[3].low  = cs4_low;
+
+	return CMD_SUCCESS;
+}
+
+
 DEFUN(show_tbf,
       show_tbf_cmd,
       "show tbf all",
@@ -685,6 +729,7 @@ int pcu_vty_init(const struct log_info *cat)
 	install_element(PCU_NODE, &cfg_pcu_no_cs_max_cmd);
 	install_element(PCU_NODE, &cfg_pcu_cs_err_limits_cmd);
 	install_element(PCU_NODE, &cfg_pcu_no_cs_err_limits_cmd);
+	install_element(PCU_NODE, &cfg_pcu_cs_lqual_ranges_cmd);
 	install_element(PCU_NODE, &cfg_pcu_queue_lifetime_cmd);
 	install_element(PCU_NODE, &cfg_pcu_queue_lifetime_inf_cmd);
 	install_element(PCU_NODE, &cfg_pcu_no_queue_lifetime_cmd);