diff --git a/nanostack/fhss_ws_extension.h b/nanostack/fhss_ws_extension.h
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+/*
+ * Copyright (c) 2015-2017, 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.
+ */
+
+/**
+ * \file fhss_ws_extension.h
+ * \brief
+ */
+
+#ifndef FHSS_WS_EXT_H
+#define FHSS_WS_EXT_H
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief unicast_timing_info Unicast timing/hopping schedule information structure.
+ */
+typedef struct unicast_timing_info {
+    unsigned unicast_channel_function:3;        /**< Unicast schedule channel function */
+    uint8_t unicast_dwell_interval;             /**< Unicast dwell interval */
+    uint_fast24_t ufsi;                         /**< Unicast fractional sequence interval */
+    uint32_t utt_rx_timestamp;                  /**< UTT-IE reception timestamp */
+} unicast_timing_info_t;
+
+/**
+ * @brief broadcast_timing_info Broadcast timing/hopping schedule information structure.
+ */
+typedef struct broadcast_timing_info {
+    unsigned broadcast_channel_function:3;      /**< Broadcast schedule channel function */
+    uint8_t broadcast_dwell_interval;           /**< Broadcast dwell interval */
+    uint16_t broadcast_slot;                    /**< Broadcast slot number */
+    uint16_t broadcast_schedule_id;             /**< Broadcast schedule identifier */
+    uint_fast24_t broadcast_interval_offset;    /**< Broadcast interval offset */
+    uint32_t broadcast_interval;                /**< Broadcast interval */
+    uint32_t bt_rx_timestamp;                   /**< BT-IE reception timestamp */
+} broadcast_timing_info_t;
+
+/**
+ * @brief fhss_ws_neighbor_timing_info Neighbor timing/hopping schedule information structure.
+ */
+typedef struct fhss_ws_neighbor_timing_info {
+    uint8_t clock_drift;                        /**< Neighbor clock drift */
+    uint8_t timing_accuracy;                    /**< Neighbor timing accuracy */
+    unicast_timing_info_t uc_timing_info;       /**< Neighbor unicast timing info */
+    broadcast_timing_info_t bc_timing_info;     /**< Neighbor broadcast timing info */
+} fhss_ws_neighbor_timing_info_t;
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // FHSS_WS_EXT_H