# Challenges in Wireless System Integration as Enablers for Indoor Context Aware Environments
## 1 Introduction
Moreover, indoor scenarios represent a relevant part of Context Aware environments, such as indoor vehicular communications within Intelligent Transportation Systems Page: 2 (ITS) (e.g., passenger trains, freight handling, in flight aircraft communications), Smart Health (eHealth, mHealth, Ambient Assisted Living), Context-based marketing and shopping, home and building automation systems, indoor tracking and location systems and many other applications inherent to the progressive adoption of Smart Cities/Smart Region paradigms. It is also worth noting that node density and distribution are of interest in assessing network performance and providing alternative network metrics and functionalities. In [10], the node concentration concept is presented, which considers the average number of neighbors connected to each node, given a specific transmission power. This is used in order to implement an enhance Ad-hoc On-demand Distance Vector protocol which employs a node concentration driven gossiping approach for limiting the flooding of the route request packets, which impact network performance. In [11], agent-modelled IoT networks of different scales are simulated, with the goal of analyzing issues and bottlenecks at communication level, showing the influence of node concentration and distribution. Impact of interference on wireless sensor networks has been analyzed in [12] showing that IEEE 802.11 and microwave ovens cause significant increases in Packet Error Rates, raising their values from a typical value of approximately 2% with no interference sources present to an upward of 25% depending upon the distances among the different nodes and interferer sources. Other aspects can be also considered, such as node distribution and the role of data acquisition in IoT enhanced environments, such as virtual agricultural systems [13]. Further considerations in WSN operation can be found in relation with operation in environments in which multiple data flows not only own different priorities but also have different levels of importance or criticality, leading to mixed criticality scenarios, which have been studied in the case of Wireless HART (Highway Addressable Remote Transducer Protocol) systems [14]. Analyzing the impact of interference is a complex issue, due to the variability and nature of the different interference sources. In general terms, interference can be considered non-correlated to the useful signals which are transmitted within the target transmitter. In this way, all interference sources (intra-system, inter-system and background noise) can be described in terms of additive noise, without loss of generality, enabling the selective introduction of potential interference sources. In this way, a dense array of transmitters has been considered, which can be activated as required in order to analyze multiple interference scenarios. In this work, an extensive analysis of wireless sensor network performance within indoor scenarios emulating Context Aware applications will be described. In order to analyze potential performance metrics, precise scenario modelling and analysis will be derived by employing ad-hoc deterministic tools, in which complete scenario as well as network complexity will be considered. Different network densities and node distributions will be considered, as well as static (i.e., infrastructure) and variable (i.e., wearable) nodes within the scenario, in order to evaluate variations of interference spectral power densities and hence, degradation within performance metrics.