# Open Radio Access Networks For Smart IoT Systems: State of Art and Future Directions
## 4 Challenges and Future Research Directions
### Future Research Directions  
#### 4.2.1 O-RAN for IoT Applications  
Designing O-RAN that supports IoT applications effectively will involve considering scalability, flexibility, resource efficiency, and seamless integration with the diverse IoT devices and use cases, i.e., starting from scalable architectures that support low power, high data rates, and higher-performance devices to dynamic network slicing capabilities implemented in dedicated virtual networks for different IoT use cases where each slice is customized to meet specific IoT application requirements. Traffic models and analysis on  
Figure 4: Attack spaces in O-RAN assisted IoT systems. IoT applications can characterize the traffic generated by IoT applications and improve the efficacy of network resource management [88]. QoS differentiation mechanisms can prioritize critical IoT applications to allocate network resources accordingly, as well as robust security by design standards that protect IoT devices and data by enforcing continuous monitoring, authentication, encryption, and threat detection mechanisms tailored to IoT requirements. Seamless integration with edge computing infrastructures can enable real-time data processing and decision-making while reducing latency for time-sensitive IoT applications. The development of standardized interfaces and protocols can promote interoperability among different devices, vendors, IoT applications, and energy-efficient communication protocols that boost the lifetime of the battery-powered devices, as well as facilitate cross-domain orchestration and communication. Dynamic frequency allocation mechanisms that optimize spectrum usage while minimizing interference among IoT devices will also be required, as will APIs and interfaces that enable third-party developers and IoT solution providers to innovate and integrate with O-RAN. For O-RAN to remain relevant in supporting the next-generation IoT applications, the O-RAN concept should remain adaptable and evolving to meet the changing dynamics of IoT applications. This can only be achieved with continuous research and development involving collaboration among standardization bodies and industry technocrats to align O-RAN standards with emerging IoT standards to ensure seamless integration and compatibility. As described in Section 2, O-RAN has defined standardized interfaces (eCPRI, Fronthaul, F1, O1, etc.) to promote flexibility and interoperability among cellular vendors for yielding lower operational and capital expenditures. In this context, with the aid of the network slicing concepts introduced by 5G, these interfaces, if standardized for IoT applications, could promote interoperability within and among IoT systems, just like in the case of the production line of a smart factory as demonstrated in [59] or the traffic steering process as depicted in [57]. Traditionally, IoT communications utilize short-range communication technologies such as BLE, GSM, Wi-Fi, ZigBee, etc. Recently, IoT connectivity has been extended to long-range, low-power WAN (LPWAN), such as LoRaWAN, NB-IoT, Sigfox, and LoRa. Integrating 5G networks with LPWAN technologies based on new architecture such as O-RAN will significantly improve IoT service use cases for industrial automation, smart cities, and other applications [89; 90]. Note that how to effectively integrate O-RAN interfaces with IoT applications or implement IoT-specific protocols like the RFID, NB-IoT, LoRAWAN, etc., in O-RAN remain unsolved problems that require further research concerning system modeling, simulation, and empirical evaluations. Even though NB-IoT operates alongside the LTE in the same frequency band, it is evident that the next-generation IoT applications [91] have diverging QoS and reliability requirements that NB-IoT cannot directly satisfy, for instance, live-streaming video surveillance in smart cities or remote surgery in healthcare, which are both high-bandwidth and low-latency applications, or autonomous vehicles, which have stringent latency of 1 ms and high mobility requirements.