LoRa is a long range, low power, low bit rate, single hop wireless communication technology. It is intended to be used for Internet of Things (IoT) networks, where devices are battery powered and limited bandwidth is needed. In combination with its scalability and the low end device price, LoRa is a candidate technology for low bandwidth industrial applications with a high number of communication devices spread across large areas. The use case for this paper is taken from the flower industry, where a large number of trolleys need to communicate with a server during their movement across the auction floor area. Once trolleys are outside of the auction floor they can use the public LoRaWAN network to communicate with the server, without switching communication technology. The LoRaWAN network consists of multiple end nodes and a single gateway per cell, acting as a transparent bridge between the end nodes and the network server. The measurements show that with a single LoRa gateway we can cover an indoor area of around 34000m2 only with spreading factor 7, while for spreading factor 12 the total covered area will be even higher. Also, the area outside the factory is covered when switching to spreading factor 12. We also show that the number of nodes (trolleys) that can be served by a gateway in such a case can be as high as 6000.

As LoRaWAN networks are actively being deployed in the field, it is important to comprehend the limitations of this low power wide area network technology. Previous work has raised questions in terms of the scalability and capacity of LoRaWAN networks as the number of end devices grows to hundreds or thousands per gateway. Some works have modeled LoRaWAN networks as pure ALOHA networks, which fails to capture important characteristics such as the capture effect and the effects of interference. Other works provide a more comprehensive model by relying on empirical and stochastic techniques. This paper uses a different approach where a LoRa error model is constructed from extensive complex baseband bit error rate simulations and used as an interference model. The error model is combined with the LoRaWAN MAC protocol in an ns-3 module that enables to study multichannel, multispreading factor, multi-gateway, bi-directional LoRaWAN networks with thousands of end devices. Using the LoRaWAN ns-3 module, a scalability analysis of LoRaWAN shows the detrimental impact downstream traffic has on the delivery ratio of confirmed upstream traffic. The analysis shows that increasing gateway density can ameliorate but not eliminate this effect, as stringent duty cycle requirements for gateways continue to limit downstream opportunities.

As open standards for the Internet of Things gain traction, the current Intranet of Things will evolve to a truly open Internet of Things, where constrained devices are first class citizens of the public Internet. However, the large amount of control over constrained networks offered by today's vertically integrated platforms, becomes even more important in an open IoT considering its promise of direct end-to-end interactions with constrained devices. In this paper a set of challenges is identified for controlling interactions with constrained networks that arise due to their constrained nature and their integration with the public Internet. Furthermore, a number of solutions are presented for overcoming these challenges by means of an intercepting intermediary at the edge of the constrained network.

The Constrained Application Protocol (CoAP) is a new Internet protocol that is currently being standardized. CoAP allows access to the drastically increasing number of smart objects and their sensing resources from virtually anywhere. It is a light-weight protocol designed to cope with the restrictions imposed by the limited resources (CPU, memory, power,...) of many smart objects. Depending on the application, information from individual objects might not be sufficient, reliable, or useful. An application may need to aggregate and/or compare data from a group of objects in order to obtain accurate results. Although multicast may be used to transmit the same request to several objects, multicast communication with smart objects has some disadvantages. Programming individual requests is another solution but lacks flexibility and opportunities for reusability. In this paper we propose a novel CoAP-based approach for communication with a group of resources across multiple smart objects. This approach organizes the group of resources that should be accessed into a new CoAP resource, called an entity, and nicely integrates several important aspects of entity management: creation, validation, usage and manipulation. In order to demonstrate the feasibility of this approach we present an implementation and experimental validation.

As embedded networks are evolving to open systems, it's becoming possible to create new applications on top of these existing embedded systems. However, developing new applications can be difficult due to the large diversity of protocols that exist today. In this paper, the authors demonstrate how employing the CoAP protocol can enable rapid application development by re-using well-known principles from the Web development world. Furthermore, we also demonstrate how a number of extensions to CoAP help to lower the barrier for developing applications even further.