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Internet of Things (IoT) expansion led the market to find alternative communication technologies since existing protocols are insufficient in terms of coverage, energy consumption to fit IoT needs. Low Power Wide Area Networks (LPWAN) emerged as an alternative cost-effective communication technology for the IoT market. LoRaWAN is an open LPWAN standard developed by LoRa Alliance and has key features i.e., low energy consumption, long-range communication, builtin security, GPS-free positioning. In this paper, we will introduce LoRaWAN technology, the state of art studies in the literature and provide open opportunities. Several LPWANs emerged on both licensed and unlicensed bands, LoRaWAN, Sigfox and, NB-IoT are widely deployed vital technologies [3].Sigfox is an ultra-narrow band network that is patented and operated by Sigfox. Sigfox occupies 100 Hz and operates at 433MHz, 868MHz and 915MHz frequencies depending on the geographical regions. Technology has strict constraints on the number of packets (140 per day) and the packet size (12 bytes) to be sent. Also, LoRaWAN has similar policies to prevent network congestion allowing channels to be available only %1 duty-cycle for EU 868MHz (See Section 2.4.7). NB-IoT is an ultra-narrow band technology developed by the 3GPP group which can be adopted on GSM and LTE networks. It occupies 200 MHz bandwidth and can reach up to 200 kbps data transmission speed. Compared to LoRaWAN, Sigfox and NB-IoT operated by global network operators which limit deployments of the private networks [4].An overview comparison of the three networks is shown in Table 1. When LPWAN characteristics are considered LoRaWAN becomes a strong candidate for both scientific and industrial uses cases.LoRa referrer to Long Range and a physical layer technology patented by Semtech [5].LoRaWAN is an open protocol proposed by the LoRa Alliance which enables the MAC layer for the network [6].In this study, we will introduce the technological aspects of LoRaWAN and the state of art studies fulfilled about LoRaWAN till today. LoRaWAN protocol was first released in 2015 and had a few minor revisions, the differences in the protocol has been highlighted in the relevant subsection. In the survey, we will introduce LoRaWAN in depth both technological aspects and the use cases of its different areas. We categorized literature studies as in Figure 1. Studies are classified as two main sections; network technology and the applications, each section has own sub-branches. The majority of the work is focused on the coverage tests and applicability of the technology for different fields from large scale smart city applications to personal tracking assets. However, there are still gaps in the literature where researchers can address these problems such as post-disaster communication, decentralized networks, network management, and Adaptive Data Rate.

Background: Cardiac surgery often represents the only treatment option in patients with infective endocarditis (IE). However, IE surgery may lead to a sudden release of inflammatory mediators, which is associated with the severity of postoperative organ dysfunction. We investigated the impact of hemoadsorption during IE surgery on postoperative organ dysfunction. Methods: This multi-center, randomized, non-blinded, controlled trial assigned patients undergoing cardiac surgery for IE to hemoadsorption [integration of CytoSorb® to cardiopulmonary bypass (CPB)] or control. The Primary outcome (ΔSOFA) was defined as the difference between the mean total postoperative sequential organ failure assessment score (SOFA), calculated maximally to the 9th postoperative day, and the basal SOFA score. The analysis was by modified intention-to-treat. A predefined inter-group comparison was done using a linear mixed model for ΔSOFA including surgeon and baseline SOFA as fixed effect covariates and with the surgical center as random effect. The SOFA score assesses dysfunction in six organ systems, each scored from zero to four. Higher scores indicate worsening dysfunction. Secondary outcomes were 30-day mortality, durations of mechanical ventilation, vasopressor and renal replacement therapy. Cytokines were measured in the first 50 patients. Results: Between January 17, 2018 and January 31, 2020, A total of 288 patients were randomly assigned to hemoadsorption (n=142) or control (n=146). Four patients in the hemoadsorption and two in the control group were excluded as they did not undergo surgery. The primary outcome ΔSOFA did not differ between the hemoadsorption and the control group (1.79 ± 3.75 and 1.93 ± 3.53, respectively, 95% CI: −1.30 to 0.83, p=0.6766). Mortality at 30 days (21% hemoadsorption vs 22% control, p=0.782), the durations of mechanical ventilation, vasopressor and renal replacement therapy did not differ between groups. Levels of IL-1β and IL-18 at the end of CPB were significantly lower in the hemoadsorption than in the control group. Conclusions: This randomized trial failed to demonstrate a reduction in postoperative organ dysfunction through intraoperative hemoadsorption in patients undergoing cardiac surgery for IE. Although hemoadsorption reduced plasma cytokines at the end of CPB, there was no difference in any of the clinically relevant outcome points.

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