# Towards Flexible and Cognitive Production--Addressing the Production Challenges
## 7 Cognitive Communication and Safety on Shop Floors
### Communication Systems  
In a labour intensive production process, many sequential steps must be performed to obtain the final product. If each machine, device, and component is connected, they can communicate specific information which will optimize the overall production process. Implementing a communication system among all devices within an industrial environment is a mixture of fixed and movable components, meaning that a wireless communication system is required for most movable parts, e.g., AGVs. However, also in the presented use case, the scenario is highly dynamic and workers equipped with sensors (head worn camera) can move freely within the environment. The network topology must be very flexible to cover the entire area where workers are moving. The direct communication path will then be often blocked by various objects in the environment which will be in most cases of a metallic nature which strongly attenuates wireless signals and a link failure will be likely for specific positions. Additionally, mobile components can distort and block signals during movement, rendering working links useless. When creating a wireless communication system for industrial applications, all these issues have to be considered in advance to prevent the implementation of an inoperable system. Through the use of simulations, many scenarios can be evaluated before actual implementation in the environment. Such simulations can be used to optimize the architecture and reduce the costs to a minimum to fulfill the requirements of reliability, safety, and security. The model representation of a shopfloor environment is a CAD model which is imported into the various simulation environments, in our case the CST Studio Suite. By defining material properties and interfering sources within the environment, a very detailed representation including materialistic behaviour can be achieved to estimate most of the impacts on the wireless communication link. This includes effects such as scattering, multi-path propagation, reflections, interference by other devices and many more which will occur in industrial environments. These physical effects are scarcely considered in modern industrial scenarios. Taking the harsh environment of our shopfloor into consideration, we identified the physical effects that will have the biggest impact in such a harsh environment. By the means of simulation, most of the effects mentioned are considered. Based on the initial results derived from this simulation model, it is possible to decide on several communication parameters such as topology, protocol, devices, and their antennas to achieve the maximum throughput for each position in the scenario [100]. What this means in this context is that, for each position of a wireless device, the optimum communication path can be derived. A detailed description of the model is provided in [101]. Antennas are one critical component for wireless communications, but in most cases, antennas of sensor nodes should have an omnidirectional radiation pattern so that their position can be changed arbitrarily in an unobstructed environment. In a heavily obstructed environment, such properties are not useful, and can only be of use if the object of interest is moving in the entire environment and the receiving stations are distributed all over the area. In previous work, the limiting properties of antennas of commercial off-the-shelf (COTS) devices have been thoroughly investigated [100,102]. The achievable distance with low power devices is relatively small, and, if a big area has to be covered, many central communication nodes might be required. There are several approaches when it comes to topology, which will be discussed later in this section. The structure of such an assembly line must be dynamic, and thus a communication system must support this dynamic behavior by being adaptable. The topology and protocol will have the most impact on an efficient communication system with appropriate antennas at the individual locations.