# Challenges in Wireless System Integration as Enablers for Indoor Context Aware Environments
## 5 Conclusions and Future Work  
In this work, the performance of wireless system operations in terms of radio channel analysis has been presented, for the specific case of variable node densities in indoor context aware environments. A realistic indoor environment has been recreated and simulated with the aid of deterministic 3D Ray Launching code, implemented ad-hoc and optimized by hybrid simulation techniques in order to simulate large, complex scenarios. A fundamental aspect in order to envisage adequate deployment strategies within heterogeneous wireless networks is to consider large densities of transceivers which can coexist in regions with multiple elements, such as furnishings or the presence of users. In this way, node density variation has been analyzed from 1 node/room to 1 node/2 m\({}^{2}\), with a total of 108 potential transceivers operating simultaneously. Results have been obtained for the complete volume of the scenario and depicted for several bi-dimensional cut planes and for linear radials of received power levels. The results provide the trend in overall received power levels, ranging in averages from \(-50\) dBm to \(-30\) dBm depending on node density. Moreover, the architecture of the network has been considered, by analyzing uniformly distributed nodes as well as subsets of randomly distributed nodes, a realistic consideration particularly in the case of portable devices. Due to the fact that IoT envisages the massive adoption of body area network devices, several wearable transceivers have also been included within the scenario, exhibiting specific patterns in relation with hot-spot identification in the vicinity of the user, as well as the potential degradation in terms of received power levels due to non-line of sight operation. Wireless channel characterization enables not only to estimate received power levels with precision, it also provides information related with interference levels, which can be given by intra-system or inter-system interference, in the case of networks which can coexist within the scenario. Multiple results have been obtained in order to analyze the impact of transceiver location as well as of node density, which can be considered equivalently as an increase in the effective amount of users located within the scenario. The results show a clear influence of the scenario as well as on the negative impact on increased transceiver density, especially if the operate in a non-centralized way, typical in inter-system interference conditions. Both 2.4 GHz and 5.8 GHz frequency bands have been considered, showing different power distributions due to larger propagation losses as frequency is increased, as well as changes in scenario interaction due to modification in object size vs. wavelength. The results give rise to SNR maps, related with specific quality metrics, such as PER thresholds, indicating regions of service compliance/non-compliance, as a function of required QoS and transmission bit rates. Node density evolution as well as non-uniform concentrations lead to hot-spot formation have direct impact on overall system performance, which will be site-specific in quantitative terms but can provide overall considerations qualitatively. The proposed methodology enables accurate estimations of interference effects and hence determine optimal network  
Figure 17: Measured spectrograms for the real test scenarios for 2.4 GHz and 5.8 GHz respectively. Channel occupation is clearly observed within the 2.4 GHz band, whereas noise floor level can be observed in the case of the 5.8 GHz frequency band. configuration layouts for high node density scenarios inherent to IoT and context aware environments. Future work is related with increasing scenario case study as well as increasing system level analysis, with parametric studies in relation with QoS specific parameters, such as outage probability.