On the Performance Evaluation of a MIMO-WCDMA Transmission Architecture for Building Management Systems  
[PERSON]  
1 Department of Electrical Engineering, School of Technological Applications, Technological Educational Institute of Sterea Ellada, 344 00 Dirflies Messapieres, Greece; pgonis@teiste. management [3]. In addition, BMSs should also allow bidirectional communication with smart grid (SG) infrastructure [4; 5] in order to accurately predict energy consumption and demand. Therefore, appropriate BMS deployment requires a reliable network infrastructure able to gather and process information under various conditions. In this context, a well-known and established practice is the deployment of wireless sensor networks (WSNs) on the premises of the building, properly installed in order to measure a variety of values and report back to the central server. Proper installation should take into account minimization of overall transmission power of wireless nodes as well as indoor propagation that can significantly deteriorate signal quality. Several approaches in recent literature have attempted to provide an insight into modern BMS trends. In [6], load control and load balancing techniques are investigated, in the concept of artificial intelligence in BMS orientations. In [7], an initial attempt to create a secure data-centric BMS architecture is presented. To this end, a hierarchical namespace across application data and user identities to simplify user authentication and data access control are presented. In [8], various protocols are analyzed for BMS applications. The authors conclude that KNX, LonWork, and BACnet protocols [9] are appropriate for building automation because of their high safety, adaptability with other products, reasonable prices, and simple installation. In the same context, and in order to overcome the heterogeneity of various building protocols, in [10], the authors propose the Web-of-Things (WoT) framework, using well-known standard technologies of the Web such as HTTP and RESTful APIs, for standardizing the access to devices seen from an application point of view. In [11], a flexible WoT hierarchical architecture model is presented for the concept of smart cities and aims to interconnect various diverse technologies. In [12], the BMS concept for buildings with a large-scale automation system is presented. The basic idea was to build a control system database as an extension of the Building Information Modeling (BIM) database, which contains the definition of an automation system and a technological infrastructure controlled by that automation. Other works have focused on the performance evaluation of communication protocols for wireless sensor networks. In [13], various medium access control (MAC) protocols for synchronous/asynchronous and single/multi-channel WSNs are investigated. Single-channel MAC protocols are categorized into synchronous and asynchronous approaches, and the advantages and disadvantages of each protocol are presented. In addition, the different features required in multi-channel WSNs compared to single-channel WSNs are investigated as well. In [14], specific output metrics in WSNs such as optimum distance among nodes as well as transmission power are extracted for the case of non-fading channels, considering specific modulation schemes. The goal of the work presented in this paper is to investigate the performance of a BMS orientation, where multiple input-multiple output (MIMO)--wideband code division multiple access (WCDMA) transmission and reception is adopted for the communication with network nodes, due to its inherent capability to take advantage of multipath propagation and minimize overall transceiver complexity [15]. With respect to Figure 1, each node is equipped with a multi-antenna system and a 2-D space-time rake receiver that estimates and coherently combines multipath replicas of the transmitted signal.