## 2 Related Work  
As aforementioned, TSCH proved its efficiency with the limited resources networks [12; 23] in recent years. SDWSNs, thus, were adopted in several studies on top of TSCH to overcome challenges, such as interference and multipath fading [15], competition among the different traffic types [9; 14; 16], mobility management [17], ensuring the required QoS level [18; 19], and the scalability issue [20]. This section highlights and reviews such works in the literature. [PERSON] et al. [15] used 6 TiSCH to build centralized scheduling managed via the path computation element (PCE) protocol [24]. The issues of multipath fading and interference were addressed, and the proposed architecture was theoretically presented with no implementation or evaluation methods. [PERSON] et al. [14] constructed dedicated tracks to accommodate the control messages and to isolate them from the data ones. Each track is a path consisting of a set of nodes between a node and the controller entity. As for the SDWSN framework, the authors adopted \(\mu\)SDN, which includes only two control message types. In addition to the tracks, the scheduling approach assigns four shared timeslots for the data messages. To evaluate the efficiency of the proposed approach, a comparison process was carried out between the adopted scheduling with and without the tracks. The simulation results showed that the end-to-end delay of the application layer was reduced in the case of the TSCH tracks. [PERSON] et al. [17] proposed forwarding and TSCH scheduling over SDN (FTS-SDN) to address the topology changes caused by the node mobility. The authors adopted SDNWISE [25], and the proposed approach uses the 6 TiSCH minimal scheduling [12] during the network setup period. After that, two or more timeslots are assigned to each node; one of them is assigned to accommodate the broadcast messages, and the others are assigned to the unicast messages to dynamically adapt to the topology changes. To evaluate the proposed approach, a single mobile node moving at three different speeds is considered. The results showed that the end-to-end data delay is lower when the FTS-SDN approach is adopted. [PERSON] et al. [18] improved the SDN-WISE framework by adopting TSCH technology as the media access control (MAC) layer. They aimed to dynamically ensure the application requirements in terms of packet loss rate and time delay. Different priorities were assigned to the considered applications depending on the application's requirements. The authors added three modules to the application layer, namely traffic manager, routing process, and TSCH scheduler. These modules work with the controller to dynamically decide the adequate route and schedule. All implementation details were provided, and the evaluation process was achieved using simulation and Testbed. The results showed that the proposed approach increased the network lifetime and ensured the application's requirements. [PERSON] et al. [9] isolated the data messages from the control ones using shared timeslots. One timeslot was assigned to accommodate the control messages, in addition to several timeslots for the data ones. 6 TiSCH minimal scheduling [12] was adopted as the reference comparison case. The proposed approach was evaluated considering control and data planes, and the simulation results showed that it improved the packet delivery rate and delay in both planes. [PERSON] et al. [26] investigated the importance of SDN on top of TSCH. They compared several TSCH schedulers, namely SDN WISE-TSCH [18], the adaptive multi-hop scheduling method (AMUS) [27], the 6 TiSCH minimal scheduling function (MSF) [28], and Orchestra [29]. All these schedulers were considered in the first stage of the simulation. Then, the two schedulers that presented the best performance in the simulation (SDN WISE-TSCH and Orchestra) were selected to be compared using Testbed. The results showed that SDN WISE-TSCH outperformed the other schedulers. [PERSON] et al. [19] proposed the SDN-TSCH approach.