diff --git a/components/esp32/include/esp_wifi.h b/components/esp32/include/esp_wifi.h
index 12ac10db74..357788225a 100755
--- a/components/esp32/include/esp_wifi.h
+++ b/components/esp32/include/esp_wifi.h
@@ -144,7 +144,7 @@ typedef struct {
     uint8_t ssid[32];                     /**< SSID of AP */
     uint8_t primary;                      /**< channel of AP */
     wifi_second_chan_t second;            /**< second channel of AP */
-    signed char rssi;                         /**< single strength of AP */
+    signed char rssi;                     /**< signal strength of AP */
     wifi_auth_mode_t authmode;            /**< authmode of AP */
 }wifi_ap_list_t;
 
diff --git a/components/lwip/include/lwip/apps/dhcpserver.h b/components/lwip/include/lwip/apps/dhcpserver.h
index 325d947a8f..0214571533 100644
--- a/components/lwip/include/lwip/apps/dhcpserver.h
+++ b/components/lwip/include/lwip/apps/dhcpserver.h
@@ -165,13 +165,6 @@ typedef enum
 } dhcp_msg_option;
 
 
-/*   Defined in esp_misc.h */
-//struct dhcps_lease {
-//	bool enable;
-//	ip4_addr_t start_ip;
-//	ip4_addr_t end_ip;
-//};
-
 enum dhcps_offer_option{
 	OFFER_START = 0x00,
 	OFFER_ROUTER = 0x01,
@@ -194,6 +187,8 @@ typedef struct _list_node{
 
 typedef u32_t dhcps_time_t;
 typedef u8_t dhcps_offer_t;
+
+/* struct dhcps_lease defined in tcpip_adapter.h */
 typedef struct dhcps_lease dhcps_lease_t;
 
 typedef struct _dhcps_options{
diff --git a/components/tcpip_adapter/include/tcpip_adapter.h b/components/tcpip_adapter/include/tcpip_adapter.h
index 76f10d7759..7fb7b91d5f 100644
--- a/components/tcpip_adapter/include/tcpip_adapter.h
+++ b/components/tcpip_adapter/include/tcpip_adapter.h
@@ -32,7 +32,7 @@ struct ip_info {
     ip4_addr_t gw;
 };
 
-/*   Defined in esp_misc.h */
+/* Also used by dhcpserver.h  */
 struct dhcps_lease {
 	bool enable;
 	ip4_addr_t start_ip;