diff --git a/test/nanostack/unittest/service_libs/fhss_config/fhssconfigtest.cpp b/test/nanostack/unittest/service_libs/fhss_config/fhssconfigtest.cpp
index fbf5f34f000..37ba994162d 100644
--- a/test/nanostack/unittest/service_libs/fhss_config/fhssconfigtest.cpp
+++ b/test/nanostack/unittest/service_libs/fhss_config/fhssconfigtest.cpp
@@ -48,3 +48,13 @@ TEST(fhss_config, test_ns_fhss_create)
 {
     CHECK(test_ns_fhss_create());
 }
+
+TEST(fhss_config, test_ns_fhss_ws_set_parent)
+{
+    CHECK(test_ns_fhss_ws_set_parent());
+}
+
+TEST(fhss_config, test_ns_fhss_ws_remove_parent)
+{
+    CHECK(test_ns_fhss_ws_remove_parent());
+}
diff --git a/test/nanostack/unittest/service_libs/fhss_config/test_fhss_config.c b/test/nanostack/unittest/service_libs/fhss_config/test_fhss_config.c
index efd58838278..565ff1b8ee6 100644
--- a/test/nanostack/unittest/service_libs/fhss_config/test_fhss_config.c
+++ b/test/nanostack/unittest/service_libs/fhss_config/test_fhss_config.c
@@ -118,3 +118,38 @@ bool test_ns_fhss_configuration_set()
     ns_fhss_configuration_set(NULL, NULL);
     return true;
 }
+
+bool test_ns_fhss_ws_set_parent()
+{
+    fhss_api_t api;
+    uint8_t dest_address[8] = {1,2,3,4,5,6,7,8};
+    broadcast_timing_info_t bc_timing_info;
+    // Test without api
+    fhss_common_stub.bool_value = false;
+    if (-1 != ns_fhss_ws_set_parent(NULL, dest_address, &bc_timing_info)) {
+        return false;
+    }
+    // Test success
+    fhss_common_stub.bool_value = true;
+    if (0 != ns_fhss_ws_set_parent(&api, dest_address, &bc_timing_info)) {
+        return false;
+    }
+    return true;
+}
+
+bool test_ns_fhss_ws_remove_parent()
+{
+    fhss_api_t api;
+    uint8_t dest_address[8] = {1,2,3,4,5,6,7,8};
+    // Test without api
+    fhss_common_stub.bool_value = false;
+    if (-1 != ns_fhss_ws_remove_parent(NULL, dest_address)) {
+        return false;
+    }
+    // Test success
+    fhss_common_stub.bool_value = true;
+    if (0 != ns_fhss_ws_remove_parent(&api, dest_address)) {
+        return false;
+    }
+    return true;
+}
diff --git a/test/nanostack/unittest/service_libs/fhss_config/test_fhss_config.h b/test/nanostack/unittest/service_libs/fhss_config/test_fhss_config.h
index 3ce718ee889..ad8c4aad8b2 100644
--- a/test/nanostack/unittest/service_libs/fhss_config/test_fhss_config.h
+++ b/test/nanostack/unittest/service_libs/fhss_config/test_fhss_config.h
@@ -31,6 +31,10 @@ bool test_ns_fhss_ws_create();
 bool test_ns_fhss_delete();
 // Test setting synchronization time configuration
 bool test_ns_fhss_configuration_set();
+// Test setting WS parent
+bool test_ns_fhss_ws_set_parent();
+// Test removing WS parent
+bool test_ns_fhss_ws_remove_parent();
 
 
 #ifdef __cplusplus
diff --git a/test/nanostack/unittest/service_libs/fhss_ws/fhsswstest.cpp b/test/nanostack/unittest/service_libs/fhss_ws/fhsswstest.cpp
index a65db921ee5..07ac76d5171 100644
--- a/test/nanostack/unittest/service_libs/fhss_ws/fhsswstest.cpp
+++ b/test/nanostack/unittest/service_libs/fhss_ws/fhsswstest.cpp
@@ -88,3 +88,13 @@ TEST(fhssws, test_fhss_unicast_handler)
 {
     CHECK(test_fhss_unicast_handler());
 }
+
+TEST(fhssws, test_fhss_ws_set_parent)
+{
+    CHECK(test_fhss_ws_set_parent());
+}
+
+TEST(fhssws, test_fhss_ws_remove_parent)
+{
+    CHECK(test_fhss_ws_remove_parent());
+}
diff --git a/test/nanostack/unittest/service_libs/fhss_ws/test_fhss_ws.c b/test/nanostack/unittest/service_libs/fhss_ws/test_fhss_ws.c
index 61f0bee2884..b4d5b825259 100644
--- a/test/nanostack/unittest/service_libs/fhss_ws/test_fhss_ws.c
+++ b/test/nanostack/unittest/service_libs/fhss_ws/test_fhss_ws.c
@@ -27,6 +27,7 @@
 #include "fhss_stub.h"
 #include "fhss_callbacks_stub.h"
 #include "fhss_platform_stub.h"
+#include "channel_functions_stub.h"
 #include "common_functions_stub.h"
 
 #define VENDOR_CHANNEL          89
@@ -34,7 +35,7 @@
 #define DEFAULT_PANID           0xabcd
 #define DEFAULT_FRAME_TYPE      FHSS_DATA_FRAME
 #define DEFAULT_FHSS_STATE      FHSS_SYNCHRONIZED
-#define DEFAULT_TX_TIME         0
+#define DEFAULT_TX_TIME         1000000
 #define DEFAULT_TIMER_DELAY     0
 #define DEFAULT_FRAME_LENGTH    100
 #define DEFAULT_PHY_HEAD_LENGTH 10
@@ -54,6 +55,11 @@ static int32_t app_channel_function(const fhss_api_t *api, uint16_t slot, uint8_
     return VENDOR_CHANNEL;
 }
 
+static fhss_ws_neighbor_timing_info_t *app_no_neighbor_info(const fhss_api_t *api, uint8_t eui64[8])
+{
+    return NULL;
+}
+
 static fhss_ws_neighbor_timing_info_t *app_get_neighbor_info(const fhss_api_t *api, uint8_t eui64[8])
 {
     return &neighbor_info;
@@ -85,6 +91,10 @@ static fhss_api_t *test_generate_fhss_api(void)
     memset(&ws, 0, sizeof(fhss_ws_t));
     memset(&fhss_callbacks_stub, 0, sizeof(fhss_callbacks_stub_def));
     memset(&fhss_common_stub, 0, sizeof(fhss_common_stub_def));
+    neighbor_info.uc_timing_info.ufsi = 1000000;
+    neighbor_info.uc_timing_info.unicast_channel_function = WS_TR51CF;
+    neighbor_info.uc_timing_info.unicast_dwell_interval = 200;
+    neighbor_info.uc_timing_info.utt_rx_timestamp = 100000;
     fhss_common_stub.fhss_struct.fhss_api = &fhss_api;
     fhss_common_stub.fhss_struct.ws = &ws;
     fhss_common_stub.fhss_struct.ws->fhss_configuration.fhss_uc_dwell_interval = 200;
@@ -170,17 +180,53 @@ bool test_fhss_ws_tx_handle_callback()
     if (fhss_common_stub.fhss_struct.fhss_api->tx_handle(api, true, dest_address, DEFAULT_FRAME_TYPE, DEFAULT_FRAME_LENGTH, DEFAULT_PHY_HEAD_LENGTH, DEFAULT_PHY_TAIL_LENGTH, DEFAULT_TX_TIME) != 0) {
         return false;
     }
-    // Test fixed channel
+    // Test when no neighbor info found
     fhss_common_stub.fhss_struct.fhss_state = DEFAULT_FHSS_STATE;
+    fhss_common_stub.fhss_struct.ws->fhss_configuration.get_neighbor_info = &app_no_neighbor_info;
+    if (fhss_common_stub.fhss_struct.fhss_api->tx_handle(api, DEFAULT_IS_BC_DEST, dest_address, DEFAULT_FRAME_TYPE, DEFAULT_FRAME_LENGTH, DEFAULT_PHY_HEAD_LENGTH, DEFAULT_PHY_TAIL_LENGTH, DEFAULT_TX_TIME) != -1) {
+        return false;
+    }
+    // Test fixed channel
+    fhss_common_stub.fhss_struct.ws->fhss_configuration.get_neighbor_info = &app_get_neighbor_info;
     fhss_common_stub.fhss_struct.ws->fhss_configuration.ws_channel_function = WS_FIXED_CHANNEL;
     if (fhss_common_stub.fhss_struct.fhss_api->tx_handle(api, DEFAULT_IS_BC_DEST, dest_address, DEFAULT_FRAME_TYPE, DEFAULT_FRAME_LENGTH, DEFAULT_PHY_HEAD_LENGTH, DEFAULT_PHY_TAIL_LENGTH, DEFAULT_TX_TIME) != -1) {
         return false;
     }
-    // Test TR51 channel function
+    /* Test TR51 channel function
+     * Dest. slot:     | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
+     *                 |dest. ufsi|     900ms        |
+     * timestamps:    100000us|             1000000us|
+     */
     fhss_common_stub.fhss_struct.ws->fhss_configuration.ws_channel_function = WS_TR51CF;
-    if (fhss_common_stub.fhss_struct.fhss_api->tx_handle(api, DEFAULT_IS_BC_DEST, dest_address, DEFAULT_FRAME_TYPE, DEFAULT_FRAME_LENGTH, DEFAULT_PHY_HEAD_LENGTH, DEFAULT_PHY_TAIL_LENGTH, DEFAULT_TX_TIME) != 0) {
+    if ((fhss_common_stub.fhss_struct.fhss_api->tx_handle(api, DEFAULT_IS_BC_DEST, dest_address, DEFAULT_FRAME_TYPE, DEFAULT_FRAME_LENGTH, DEFAULT_PHY_HEAD_LENGTH, DEFAULT_PHY_TAIL_LENGTH, DEFAULT_TX_TIME) != 0)
+            || (channel_functions_stub.uint8_value != 7)) {
         return false;
     }
+    /* Test TR51 channel function when timestamp overflows
+     * Dest. slot:     | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
+     *                 |dest. ufsi|     1000ms        |
+     * timestamps:    4294867000us|           900000us|
+     */
+    neighbor_info.uc_timing_info.utt_rx_timestamp = 4294867000;
+    fhss_common_stub.fhss_struct.ws->fhss_configuration.ws_channel_function = WS_TR51CF;
+    if ((fhss_common_stub.fhss_struct.fhss_api->tx_handle(api, DEFAULT_IS_BC_DEST, dest_address, DEFAULT_FRAME_TYPE, DEFAULT_FRAME_LENGTH, DEFAULT_PHY_HEAD_LENGTH, DEFAULT_PHY_TAIL_LENGTH, 900000) != 0)
+            || (channel_functions_stub.uint8_value != 7)) {
+        return false;
+    }
+    /* Test TR51 channel function when channel list overflows
+     * Dest. slot:     | 0 | 1 | 2 | 3 |...| 0 | 1 | 2 | 3 |
+     *                 |dest. ufsi|      10000ms      |
+     * timestamps:        100000us|         10100000us|
+     */
+    neighbor_info.uc_timing_info.utt_rx_timestamp = 100000;
+    uint32_t tx_time = neighbor_info.uc_timing_info.utt_rx_timestamp + (fhss_common_stub.fhss_struct.number_of_channels * neighbor_info.uc_timing_info.unicast_dwell_interval * 1000);
+    fhss_common_stub.fhss_struct.ws->fhss_configuration.ws_channel_function = WS_TR51CF;
+    if ((fhss_common_stub.fhss_struct.fhss_api->tx_handle(api, DEFAULT_IS_BC_DEST, dest_address, DEFAULT_FRAME_TYPE, DEFAULT_FRAME_LENGTH, DEFAULT_PHY_HEAD_LENGTH, DEFAULT_PHY_TAIL_LENGTH, tx_time) != 0)
+            || (channel_functions_stub.uint8_value != 2)) {
+        return false;
+    }
+    // For more coverage, set neighbor info NULL
+    memset(&neighbor_info, 0, sizeof(fhss_ws_neighbor_timing_info_t));
     // Test direct hash channel function
     fhss_common_stub.fhss_struct.ws->fhss_configuration.ws_channel_function = WS_DH1CF;
     if (fhss_common_stub.fhss_struct.fhss_api->tx_handle(api, DEFAULT_IS_BC_DEST, dest_address, DEFAULT_FRAME_TYPE, DEFAULT_FRAME_LENGTH, DEFAULT_PHY_HEAD_LENGTH, DEFAULT_PHY_TAIL_LENGTH, DEFAULT_TX_TIME) != 0) {
@@ -418,3 +464,62 @@ bool test_fhss_unicast_handler()
     fhss_common_stub.callback[0](fhss_common_stub.fhss_struct.fhss_api, DEFAULT_TIMER_DELAY);
     return true;
 }
+
+bool test_fhss_ws_set_parent()
+{
+    uint8_t dest_address[8] = {1,2,3,4,5,6,7,8};
+    broadcast_timing_info_t bc_timing_info;
+    memset(&bc_timing_info, 0, sizeof(broadcast_timing_info_t));
+    fhss_api_t *api = test_generate_fhss_api();
+
+    // Test without WS enabled FHSS
+    fhss_structure_t fake_fhss_structure;
+    memset(&fake_fhss_structure, 0, sizeof(fhss_structure_t));
+    if (-1 != fhss_ws_set_parent(&fake_fhss_structure, dest_address, &bc_timing_info)) {
+        return false;
+    }
+    // Test success
+    bc_timing_info.broadcast_channel_function = WS_TR51CF;
+    bc_timing_info.broadcast_dwell_interval = 250;
+    bc_timing_info.broadcast_interval = 1000;
+    bc_timing_info.broadcast_interval_offset = 2000;
+    bc_timing_info.broadcast_schedule_id = 1;
+    bc_timing_info.broadcast_slot = 10;
+    bc_timing_info.bt_rx_timestamp = 100000;
+    if (0 != fhss_ws_set_parent(&fhss_common_stub.fhss_struct, dest_address, &bc_timing_info)
+            || (fhss_common_stub.fhss_struct.ws->parent_bc_info->broadcast_channel_function != WS_TR51CF)
+            || (fhss_common_stub.fhss_struct.ws->parent_bc_info->broadcast_dwell_interval != 250)
+            || (fhss_common_stub.fhss_struct.ws->parent_bc_info->broadcast_interval != 1000)
+            || (fhss_common_stub.fhss_struct.ws->parent_bc_info->broadcast_interval_offset != 2000)
+            || (fhss_common_stub.fhss_struct.ws->parent_bc_info->broadcast_schedule_id != 1)
+            || (fhss_common_stub.fhss_struct.ws->parent_bc_info->broadcast_slot != 10)
+            || (fhss_common_stub.fhss_struct.ws->parent_bc_info->bt_rx_timestamp != 100000)) {
+        return false;
+    }
+    // Test updating value
+    bc_timing_info.broadcast_interval_offset = 5000;
+    if (fhss_common_stub.fhss_struct.ws->parent_bc_info->broadcast_interval_offset != 5000) {
+        return false;
+    }
+    return true;
+}
+
+bool test_fhss_ws_remove_parent()
+{
+    uint8_t dest_address[8] = {1,2,3,4,5,6,7,8};
+    fhss_api_t *api = test_generate_fhss_api();
+    broadcast_timing_info_t bc_timing_info;
+    fhss_common_stub.fhss_struct.ws->parent_bc_info = &bc_timing_info;
+
+    // Test without WS enabled FHSS
+    fhss_structure_t fake_fhss_structure;
+    memset(&fake_fhss_structure, 0, sizeof(fhss_structure_t));
+    if (-1 != fhss_ws_remove_parent(&fake_fhss_structure, dest_address)) {
+        return false;
+    }
+    // Test success
+    if ((0 != fhss_ws_remove_parent(&fhss_common_stub.fhss_struct, dest_address)) || (fhss_common_stub.fhss_struct.ws->parent_bc_info != NULL)) {
+        return false;
+    }
+    return true;
+}
diff --git a/test/nanostack/unittest/service_libs/fhss_ws/test_fhss_ws.h b/test/nanostack/unittest/service_libs/fhss_ws/test_fhss_ws.h
index 9f700ef0b19..2c11bec332c 100644
--- a/test/nanostack/unittest/service_libs/fhss_ws/test_fhss_ws.h
+++ b/test/nanostack/unittest/service_libs/fhss_ws/test_fhss_ws.h
@@ -35,6 +35,8 @@ bool test_fhss_ws_write_synch_info_callback();
 bool test_fhss_broadcast_handler();
 bool test_fhss_ws_update_uc_channel_callback();
 bool test_fhss_unicast_handler();
+bool test_fhss_ws_set_parent();
+bool test_fhss_ws_remove_parent();
 
 #ifdef __cplusplus
 }
diff --git a/test/nanostack/unittest/stub/channel_functions_stub.c b/test/nanostack/unittest/stub/channel_functions_stub.c
index 9d3a54f3d5e..6c2bde5bdce 100644
--- a/test/nanostack/unittest/stub/channel_functions_stub.c
+++ b/test/nanostack/unittest/stub/channel_functions_stub.c
@@ -15,8 +15,11 @@
  * limitations under the License.
  */
 #include "nsconfig.h"
+#include "channel_functions_stub.h"
 #include <string.h>
 
+channel_functions_stub_def channel_functions_stub;
+
 int32_t dh1cf_get_uc_channel_index(uint16_t slot_number, uint8_t *mac, int16_t number_of_channels)
 {
     return 1;
@@ -29,6 +32,7 @@ int32_t dh1cf_get_bc_channel_index(uint16_t slot_number, uint16_t bsi, int16_t n
 
 int32_t tr51_get_uc_channel_index(uint16_t slot_number, uint8_t *mac, int16_t number_of_channels)
 {
+    channel_functions_stub.uint8_value = slot_number;
     return 3;
 }
 
diff --git a/test/nanostack/unittest/stub/channel_functions_stub.h b/test/nanostack/unittest/stub/channel_functions_stub.h
new file mode 100644
index 00000000000..546b0cf44ec
--- /dev/null
+++ b/test/nanostack/unittest/stub/channel_functions_stub.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2016, Arm Limited and affiliates.
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __CHANNEL_FUNCTIONS_STUB_H__
+#define __CHANNEL_FUNCTIONS_STUB_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+typedef struct {
+    uint8_t uint8_value;
+} channel_functions_stub_def;
+
+extern channel_functions_stub_def channel_functions_stub;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // __CHANNEL_FUNCTIONS_STUB_H__