# Performance Analysis of Cooperative Low-Power Wide-Area Network for Energy-Efficient B5G Systems
## 1 Introduction  
The low-power wide-area network (LPWAN) is a promising wireless platform to meet three key requirements of IoT applications distributed over wide areas; i.e., low cost, large scale deployment, and high energy efficiency. Most of all, it can be supported on battery-powered electronic devices for 10-years while communicating at low data-rates to gateways several kilometers away. It is conceived as an appealing technology to realize smart cities, smart farms, and smart buildings. In recent times, LPWAN has been actively researched in relation to sustainable and fully-connected IoT for ongoing 5G and towards 6G; i.e., long-term evolution (LTE) machine-type-communications (LTE-MTC), narrow band-IoT (NB-IoT), LoRa (long range), and Bluetooth low energy (BLE). LTE-MTC is an LPWA technology standard published by the 3 GPP, which can achieve a much higher data rate. NB-IoT is an evolution form regular MTC to massive MTC (mMTC) which was a 3 GPP standard in 2016 [1]. They all work over the licensed spectrum. LoRa operates over an unlicensed spectrum; that is, 433 MHz, 868 MHz (Europe), 915 MHz (Australia and North America), and 923 MHz (Asia). As the chip spread spectrum technology is defined by the LoRa Alliance in 2015 [2], it allows the cost of each LoRa device to be lowered with the usage of the cheap oscillator. BLE was released in 2010 as part of the Bluetooth 4.0 server's specifications [3], which works over the unlicensed 2.4 GHz band, and the transmission rangecan be up to 100 m. As supported by different standards organizations and alliances, each piece of LPWA technology shows different practical deployment potential. LTE-MTC and NB-IoT may be favored by cellular network operators due to high compatibility with existing cellular networks, while LoRa and BLE are supported by IoT operators with specific applications due to their good network scalability [4]. Among the IoT networks, LPWAN is certainly becoming the main technique envisioned to be part of the cooperative distributed networks in IoT network connectivity in the ongoing 5G and towards 6G. Recent studies have been conducted to address and analyze the performance of the LPWAN. In [5], they assess the performance of LoRaWAN--which is one of the main LPWA technology available--in terms of network performance metrics, such as range, coverage, latency, and packet delivery ratio. In [6], they derive the uplink throughput and data transmission time of a single LoRaWAN end device and analyze the maximum number of end devices which can be served by a single LoRaWAN base station. In [7], they analyze the flexibility of LoRa and propose various strategies to adapt its radio parameters to different deployment scenarios and compute the energy consumption of LoRa transceivers. In [8], they analyze the coverages and the capacities of four types of LPWAN using a real site deployment assuming traffic growth. They all explain that the LPWAN possess the ability to offer low-cost connections for a huge number of low-power devices distributed over large areas [9]. Nevertheless, the LPWAN still has several challenges to be addressed effectively, including interference management, the massive access scheme, the optimal coexistence scheme, and energy efficient schemes, which are presented with overall knowledge about LPWAN in [10]. Most of all, despite LPWAN wireless protocols enabling long-range communications (up to 10-15 km in rural zones and 2-5 km in urban zones [11]) between connected devices with minimal energy requirements (battery can last up to 10 years for low data usage cases), communications are not always guaranteed. Because it depends on data rage, availability, range, noise, and required throughput [12]. Actually, devices located in urban spaces deep inside buildings will experience severe drain in the battery, as their signals are highly attenuated, even at the closest gateway (GW) [13].