diff --git a/core/net/rime/collect.c b/core/net/rime/collect.c
index cb18d6fbd..f6b43ab5e 100644
--- a/core/net/rime/collect.c
+++ b/core/net/rime/collect.c
@@ -126,7 +126,7 @@ struct ack_msg {
    full, incoming packets are dropped instead of being forwarded. */
 #define MAX_MAC_REXMITS            2
 #define MAX_ACK_MAC_REXMITS        5
-#define REXMIT_TIME                CLOCK_SECOND * 4
+#define REXMIT_TIME                CLOCK_SECOND * 32 / NETSTACK_CONF_RDC_CHANNEL_CHECK_RATE
 #define FORWARD_PACKET_LIFETIME_BASE    REXMIT_TIME * 2
 #define MAX_SENDING_QUEUE          3 * QUEUEBUF_NUM / 4
 #define MIN_AVAILABLE_QUEUE_ENTRIES 4
diff --git a/core/net/rime/rime.c b/core/net/rime/rime.c
index 08db5b8aa..b64be1c5c 100644
--- a/core/net/rime/rime.c
+++ b/core/net/rime/rime.c
@@ -72,7 +72,7 @@ const struct mac_driver *rime_mac;
 #ifdef RIME_CONF_BROADCAST_ANNOUNCEMENT_BUMP_TIME
 #define BROADCAST_ANNOUNCEMENT_BUMP_TIME RIME_CONF_BROADCAST_ANNOUNCEMENT_BUMP_TIME
 #else /* RIME_CONF_BROADCAST_ANNOUNCEMENT_BUMP_TIME */
-#define BROADCAST_ANNOUNCEMENT_BUMP_TIME CLOCK_SECOND * 8
+#define BROADCAST_ANNOUNCEMENT_BUMP_TIME CLOCK_SECOND * 32 / NETSTACK_CONF_RDC_CHANNEL_CHECK_RATE
 #endif /* RIME_CONF_BROADCAST_ANNOUNCEMENT_BUMP_TIME */
 
 #ifdef RIME_CONF_BROADCAST_ANNOUNCEMENT_MIN_TIME