# Internet of Multimedia Things (IoMT): Opportunities, Challenges and Solutions
## 3 A Brief Review of Articles of This Special Issue
However, UWSN wireless communication is challenging due to environment and propagation losses, which include high noise, Doppler spreading, path loss, multi-path signal propagation, and high power consumption. To overcome these issues, [PERSON] et al. in [22] proposed cross layered QoS Aware routing Protocol (QoSRP). The proposed scheme is composed of underwater channel detection, channel assignment, and packets forwarding. The QoSRP selects detects the high probability vacant channel and assigns the high data rate channels to an acoustic sensor node. The QoSRP also balances the traffic, avoids congestion, and data path loops to increase PDR and throughput of the system with minimum delay along the path. Ultra Wide band (UWB) features include higher bandwidth, and it is one of the viable technologies for IoMT applications. The integration of UWB in health critical IoT applications can provide an effective and reliable solution for the monitoring of patients. Ataxia patients suffer from abnormal movement, and that severely affects walking activities. The walking activities can be classified as a normal walk, difficulty walking in a straight line, walking with heavy steps, and forward bending walking. All of these walking patterns except normal walking shows abnormality. [PERSON] et al. [23] proposed a scheme to cater to this problem. They set up the testbed in an indoor environment. They collected sample walk patterns and classified it using Support Vector Machine (SVM) algorithms, namely SVM-based Sigmoid Kernel Function (SKF) and Radial Basis Function (RBF). Results show that RBF performs better than SKF. The drawback of the proposed scheme is that it is only tested for a single person. Hence, it should be extended to monitor multiple persons. Security, privacy, and trust remain challenges in IoMT because of the openness and heterogeneity of IoMT. Access control is used to protect the confidentiality and integrity of constrained resources in IoMT services. It provides a solution to avoid any unauthorized access for multimedia applications in IoT services. However, due to increasing the number of users and multimedia services offered by the IoT platform, the access control system is becoming more and more multifaceted. Besides, access control policy evaluation reduces the performance of IoMT applications. Therefore, [PERSON] et al. [24] proposed an Attribute-Based Access Control (ABAC) policy retrieval method to improve the performance of access control policy evaluation in multimedia networks. To rebuild the policy decision tree, an attribute value level, and the depth index is introduced, thus, improve policy retrieval efficiency. Policy analysis is performed with a different number of rules and the increasing complexity of the policy. Results indicate that the proposed method is more efficient and scalable than the existing access control schemes. Increasing demand for data-intensive applications is growing users' data requirements exponentially. However, spectrum scarcity is the biggest hurdle in meeting users QoS. One of the viable solutions is to reuse and share the spectrum among the users to fulfill users demands without compromising the user's experience. Even though unlicensed spectrums are available for free, they are already overcrowded. Different network technologies such as 5G and Wi-Fi use different spectrum access mechanisms, and sharing the spectrum among them is a trivial task. To allow fair coexistence between 5G and Wi-Fi networks operating in the same spectrum, LBT is introduced to work in parallel with the CSMA for channel access. RL techniques can be adapted to make a spectrum access mechanism to learn network conditions itself and adapt to the network changes accordingly. Consequently, the network becomes sustainable and self-adaptive. [PERSON] et al. in [25] proposed Q-Learning to LTE-U to adjust the duty cycle parameters to reduce coexistence interference and improve the system data rate. A saturated network scenario is considered to evaluate the proposed scheme in the ns-3 simulator.