diff --git a/doc/manuals/vty/osmo-pcu_vty_reference.xml b/doc/manuals/vty/osmo-pcu_vty_reference.xml
index eed4d83..da6c76c 100644
--- a/doc/manuals/vty/osmo-pcu_vty_reference.xml
+++ b/doc/manuals/vty/osmo-pcu_vty_reference.xml
@@ -1536,7 +1536,7 @@
     <command id='cs threshold &lt;0-100&gt; &lt;0-100&gt;'>
       <params>
         <param name='cs' doc='Coding Scheme configuration' />
-        <param name='threshold' doc='set thresholds for error rate based CS adjustment' />
+        <param name='threshold' doc='set thresholds for error rate based downlink (M)CS adjustment' />
         <param name='&lt;0-100&gt;' doc='lower limit in %' />
         <param name='&lt;0-100&gt;' doc='upper limit in %' />
       </params>
@@ -1545,13 +1545,13 @@
       <params>
         <param name='no' doc='Negate a command or set its defaults' />
         <param name='cs' doc='Coding Scheme configuration' />
-        <param name='threshold' doc='set thresholds for error rate based CS adjustment' />
+        <param name='threshold' doc='set thresholds for error rate based downlink (M)CS adjustment' />
       </params>
     </command>
     <command id='cs downgrade-threshold &lt;1-10000&gt;'>
       <params>
         <param name='cs' doc='Coding Scheme configuration' />
-        <param name='downgrade-threshold' doc='set threshold for data size based CS downgrade' />
+        <param name='downgrade-threshold' doc='set threshold for data size based downlink (M)CS downgrade' />
         <param name='&lt;1-10000&gt;' doc='downgrade if less octets left' />
       </params>
     </command>
@@ -1559,13 +1559,13 @@
       <params>
         <param name='no' doc='Negate a command or set its defaults' />
         <param name='cs' doc='Coding Scheme configuration' />
-        <param name='downgrade-threshold' doc='set threshold for data size based CS downgrade' />
+        <param name='downgrade-threshold' doc='set threshold for data size based downlink (M)CS downgrade' />
       </params>
     </command>
     <command id='cs link-quality-ranges cs1 &lt;0-35&gt; cs2 &lt;0-35&gt; &lt;0-35&gt; cs3 &lt;0-35&gt; &lt;0-35&gt; cs4 &lt;0-35&gt;'>
       <params>
         <param name='cs' doc='Coding Scheme configuration' />
-        <param name='link-quality-ranges' doc='Set link quality ranges' />
+        <param name='link-quality-ranges' doc='Set link quality ranges for each uplink CS' />
         <param name='cs1' doc='Set quality range for CS-1 (high value only)' />
         <param name='&lt;0-35&gt;' doc='CS-1 high (dB)' />
         <param name='cs2' doc='Set quality range for CS-2' />
@@ -1581,7 +1581,7 @@
     <command id='mcs link-quality-ranges mcs1 &lt;0-35&gt; mcs2 &lt;0-35&gt; &lt;0-35&gt; mcs3 &lt;0-35&gt; &lt;0-35&gt; mcs4 &lt;0-35&gt; &lt;0-35&gt; mcs5 &lt;0-35&gt; &lt;0-35&gt; mcs6 &lt;0-35&gt; &lt;0-35&gt; mcs7 &lt;0-35&gt; &lt;0-35&gt; mcs8 &lt;0-35&gt; &lt;0-35&gt; mcs9 &lt;0-35&gt;'>
       <params>
         <param name='mcs' doc='Coding Scheme configuration' />
-        <param name='link-quality-ranges' doc='Set link quality ranges' />
+        <param name='link-quality-ranges' doc='Set link quality ranges for each uplink MCS' />
         <param name='mcs1' doc='Set quality range for MCS-1 (high value only)' />
         <param name='&lt;0-35&gt;' doc='MCS-1 high (dB)' />
         <param name='mcs2' doc='Set quality range for MCS-2' />
diff --git a/src/bts.h b/src/bts.h
index 54a29cb..7ef5a3f 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -142,12 +142,15 @@
 	/* 0 to support resegmentation in DL, 1 for no reseg */
 	uint8_t dl_arq_type;
 
-	uint8_t cs_adj_enabled;
-	uint8_t cs_adj_upper_limit;
-	uint8_t cs_adj_lower_limit;
+	uint8_t cs_adj_enabled; /* whether cs_adj_{upper,lower}_limit are used to adjust DL CS */
+	uint8_t cs_adj_upper_limit; /* downgrade DL CS if error rate above its value */
+	uint8_t cs_adj_lower_limit; /* upgrade DL CS if error rate below its value */
+	/* downgrade DL CS when less than specified octets are left in tx queue. Optimization, see paper:
+	  "Theoretical Analysis of GPRS Throughput and Delay" */
+	uint16_t cs_downgrade_threshold;
+	/* Link quality range for each UL (M)CS. Below or above, next/prev (M)CS is selected. */
 	struct {int16_t low; int16_t high; } cs_lqual_ranges[MAX_GPRS_CS];
 	struct {int16_t low; int16_t high; } mcs_lqual_ranges[MAX_EDGE_MCS];
-	uint16_t cs_downgrade_threshold; /* downgrade if less packets left (DL) */
 	uint16_t ws_base;
 	uint16_t ws_pdch; /* increase WS by this value per PDCH */
 
diff --git a/src/pcu_vty.c b/src/pcu_vty.c
index 996ce61..2fd57d0 100644
--- a/src/pcu_vty.c
+++ b/src/pcu_vty.c
@@ -938,7 +938,7 @@
 	return CMD_SUCCESS;
 }
 
-#define CS_ERR_LIMITS_STR "set thresholds for error rate based CS adjustment\n"
+#define CS_ERR_LIMITS_STR "set thresholds for error rate based downlink (M)CS adjustment\n"
 DEFUN(cfg_pcu_cs_err_limits,
       cfg_pcu_cs_err_limits_cmd,
       "cs threshold <0-100> <0-100>",
@@ -977,7 +977,7 @@
 	return CMD_SUCCESS;
 }
 
-#define CS_DOWNGRADE_STR "set threshold for data size based CS downgrade\n"
+#define CS_DOWNGRADE_STR "set threshold for data size based downlink (M)CS downgrade\n"
 DEFUN(cfg_pcu_cs_downgrade_thrsh,
       cfg_pcu_cs_downgrade_thrsh_cmd,
       "cs downgrade-threshold <1-10000>",
@@ -1006,7 +1006,7 @@
 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"
+      CS_STR "Set link quality ranges for each uplink CS\n"
       "Set quality range for CS-1 (high value only)\n"
       "CS-1 high (dB)\n"
       "Set quality range for CS-2\n"
@@ -1040,7 +1040,7 @@
 DEFUN(cfg_pcu_mcs_lqual_ranges,
       cfg_pcu_mcs_lqual_ranges_cmd,
       "mcs link-quality-ranges mcs1 <0-35> mcs2 <0-35> <0-35> mcs3 <0-35> <0-35> mcs4 <0-35> <0-35> mcs5 <0-35> <0-35> mcs6 <0-35> <0-35> mcs7 <0-35> <0-35> mcs8 <0-35> <0-35> mcs9 <0-35>",
-      CS_STR "Set link quality ranges\n"
+      CS_STR "Set link quality ranges for each uplink MCS\n"
       "Set quality range for MCS-1 (high value only)\n"
       "MCS-1 high (dB)\n"
       "Set quality range for MCS-2\n"