# A B5G Non-Terrestrial-Network (NTN) and Hybrid Constellation Based Data Collection System (DCS)
## 2 Relate Work  
There are two most popular IoT technologies, namely low-power wide-range (LoRa) and Narrow Band Internet of Things (NB-IoT). The former requires an independent terrestrial data collection device. The latter can apply the 4G LTE station as infrastructure. LoRa has received increasing attention for the following three main reasons [8]: (a) companies building a large industry to collect data and control remotely, (b) 45.12% people worldwide with 3.5 billion smart phones willing to apply IoT systems remotely by the phone, and (c) people interested in monitoring and controlling their appliances at low cost and power. LoRa-based IoT systems offer a cost-effective and straightforward application [9; 10]. It adopts a modulation technique that is capable of transmitting 300-19,200 bps data rate, and the maximum communication distance is about 11 km. In contrast, Bluetooth, Wi-Fi, and ZigBee cannot cover a wide area [11]. A LoRa-based automation system is designed and developed to control appliances in industry [12]. In IoT systems, access control systems are built using Blockchain Managers (BCMs) for securing IoT access [13]. However, this terrestrial IoT system needs to be equipped with an independent data receiving device. And it needs to rely on the ground network for data collection [14]. Furthermore, the limited reception of the receiving station prevents global coverage. With the gradual maturing of B5G and cloud technology, numerous wireless electronic devices have access to cloud servers, which allow the users to acquire and analyze large amounts of data [15; 16; 17; 18]. A NB-IoT system for remote fire monitoring is proposed [19]. It is driven by a magnetic-assisted noncontact energy harvester (MN-EH), which hybridizes piezoelectric and electromagnetic genes. This system can solve the energy problem using the NB system. Although many IoT systems have been widely used in terrestrial applications, they have many disadvantages: depending on the ground infrastructure; small ground coverage and customized signal model. Non-uniform terminal sensors require IoT systems compatible with different frequency bands, modulation methods, and coding methods. A qualified IoT system must be capable of global coverage, express scanning, and multi-mode compatibility. These challenges are difficult to meet simultaneously for traditional terrestrial IoT systems. Fortunately, a CubeSat constellation-based NTN system can solve these problems. As a space data relay system [20; 21], non-geostationary (NGSO) systems provide high-bandwidth data services to aircraft, ships, and terrestrial sensors. Some established NTN systems are shown in Table 1. Due to the high altitude, these NTN systems can achieve global coverage. The diameter of the coverage area can be up to 1.5 times the orbital altitude [22; 23]  
However, these NTN systems must still rely on independent ground gateway equipment. They are unable to communicate with the 5G system directly. This shortcoming will not only increase the construction cost but also degrade the communication performance. Some important key performance indicators (KPI) of B5G [24] are shown in Table 2. The main application scenarios of NTN are oceans, mountains, and remote regions. For those scenarios, terrestrial infrastructure cannot be constructed [25]. The NTN-mMTC system is the integration of the NTN system with the terrestrial 5G network. The NTN system enables the construction of IoT collection equipment on satellite platforms. This design guarantees global coverage and fast scanning. The mMTC technology uses the terrestrial 5G network as the backhaul network for IoT. DCS equipment is the key technology of NTN-mMTC. The performance of the DCS determines ground sensor data collection performance. Especially for scenarios with low emission energy and complex signal modes, the performance of DCS is the most important  
As a satisfactory DCS equipment, it should be compatible with different IoT signal models such as AIS, ADS-B, vehicle position applications, and various remote sensors.