# A Spectrum Management Platform Architecture to Enable a Sharing Economy in 6G
## 5 Use Case: Spectrum Access in Massive IoT  
To illustrate how significant the benefits can be of deploying spectrum through an architecture such as HODNET, we analyse the following use case of massively deployed wireless IoT devices within a limited area. It is expected that over the next ten years the number of IoT devices will reach densities of several million devices per square kilometre. Current radio access models, including both grant-based and grant-free models have not been designed to guarantee wireless connectivity on this scale. This is because operators cannot currently provide enough spectrum capacity to satisfy the demands of these devices [30]. In this use case, HODNET will act as the platform linking IoT networks to entities offering wireless spectrum and connectivity. We envisage that a RAN operator initially manages its wireless network independently (i.e., in the traditional way), resulting in inadequate spectrum access. By introducing HODNET as a brokering and control entity, other operators could be invited to trade spectrum access and alleviate each other's burden based on the new spectrum-sharing paradigm. HODNET coordinates with the operators to optimise the spectrum usage through the monitoring and sharing functionality in the Radio Resources Sharing Plane and, as such, increases usable capacity. For our analysis, we focus on two performance metrics:  
* Signal to Interference plus Noise Ratio (SINR): this is the average SINR experienced by all IoT devices in the network;
* Probability of denying connectivity: this is the percentage of devices that cannot achieve their bit rate requirements. We used MATLAB to simulate a dense deployment of IoT devices served by a set of RANs that belong to different network operators, all deployed in an open-air area of 250 m \(\times\) 250 m. We then introduce HODNET and assess how both approaches (with and without HODNET) can provide connectivity to IoT devices while optimising network capacity, and how they then perform as the number of devices increases. Each RAN can be either a 5G Base Station (gNB) or a Wi-Fi 802.11 ah Access Point (AP). Specifically, the 5G connectivity is provided by 4 gNBs and the Wi-Fi connectivity is offered by 16 802.11 ah APs. Furthermore, the 20 nodes belong to 4 different operators, with each one managing 5 nodes. We assume that each node offers a 5 MHz uplink channel operating on the 880-915 MHz and a 4 MHz uplink channel on 900-928 MHz frequency bands in the case of the gNBs and Wi-Fi APs, respectively. We also assume that the IoT devices have transmission power capabilities varying between 1 and 10 dBm and data rates varying between 8 kbps and 128 kbps. The selected settings are representative of a dense environment [31], and follow 3 GPP and IEEE specifications. Note that the aim of this implementation is to demonstrate the benefits of our novel spectrum-sharing paradigm that we envision for next-generation 6G networks, through the massive IoT use case involving technologies currently available in the market, i.e., Wi-Fi and 5G. As we will demonstrate in the rest of this section, these results will encourage further investigation to extend our approach into next-generation 6G-based technologies. Moreover, for the sake of comparison, we consider a simplified version of 5G that connects each IoT device to the closest of its 5 available nodes and does not have access to the connectivity offered by other operators, whereas the HODNET Controller can utilisethe whole environment. For this, HODNET implements a Sharing-Economy-based Smart Connectivity algorithm on its Radio Resource Sharing Plane based on information gathered from the Infrastructure Plane. This information includes the Received Signal Strength Indicator (RSSI) monitored by the RANs from each IoT device and the number of devices connected to each RAN. This algorithm connects dynamically each IoT device to the RAN belonging to any RAN operator that has the smallest number of connections, and which provides a sufficient RSSI based on the data rate requirements.