International Journal of Sensors and Sensor Networks 2015; 3(1-1): 1-10 Published online November 28, 2014 (http://www.sciencepublishinggroup.com/j/ijssn) doi: 10.11648/j.ijssn.s.2015030101.11 Heterogeneous cognitive radio sensor networks through RoF-MIMO technologies Shozo Komaki 1 , Sevia M. Idrus 2 , Toshio Wakabayashi 1 , A. K. M. Muzahidul Islam 1 , Sabariah Baharun 1 , Wan Haslina Hassan 1 1 Department of Electronics Systems Engineering, MJIIT, UTM, Jalan Semarak, 54100, Kuala Lumpure, Malaysia 2 Head of Photonics Fabrication Lab., Faculty of Electrical Engineering, UTM, Jalan Universiti, UTM, Johor, Malaysia Email address: komaki@ic.utm.my (S. Komaki) , sevia@fke.utm.my (S. Idrus), twakabayashi@ic.utm.my(T. Wakabayashi), akmmislam@ic.utm.my (A. K. M. M. Islam), drsabariah@ic.utm.my (S. Baharun), wanhaslina@ic.utm.my (W. H. Hassan) To cite this article: Shozo Komaki, Sevia M. Idrus, Toshio Wakabayashi, A. K. M. Muzahidul Islam, Sabariah Baharun, Wan Haslina Hassan. Heterogeneous Cognitive Radio Sensor Networks through RoF-MIMO Technologies. International Journal of Sensors and Sensor Networks. Special Issue: Wireless Sensors and Sensor Networks. Vol. 3, No. 1-1, 2015, pp. 1-10. doi: 10.11648/j.ijssn.s.2015030101.11 Abstract: Recently, smart grid networks are researched and developed for the greening of the energy consumption. When introducing these into the university or the community, it is required not only the wide area cooperation and the high-speed monitoring & control, but also the construction of the heterogeneous infrastructure with the security and the flexibility. In this paper, recent research on the Radio on Fiber (RoF) technologies are described, and the technology application to the university and/or community smart grid is suggested. And also it is proposed the wide area remote connection of heterogeneous cognitive radio networks by RoF-MIMO (Multiple Input Multiple Output) technologies. Network throughput and the network outage rate using various types of RoF-MIMO systems are calculated and compared. And it is shown that the distributed parallel RoF-MIMO can improve the throughput and the outage performance simultaneously. Prototyping Experiment is also conducted in the faculty building and confirms that the network outage is improved by the distributed parallel RoF-MIMO. Keywords: Wireless Sensor Networks, RoF-MIMO, Smart Grids, Heterogeneous Networking 1. Introduction Smart grids using wireless sensor networks are key issue to establish an ecological and sustainable society. Recently, cognitive radio sensor network (CRSN) technology has been proposed to solve the radio spectrum utilization problem. [1] This technology is now considered to be the wireless ad hoc networks, because the smaller cell spectrum sensing and operation is effective to find the spectrum hole and slots. It has the higher performance comparing with the macro-cell operation. However ad hoc small cell networks have some problems in global extension of the heterogeneous system operation such as community networks. For the CRSN in home and/or business office, the uniform wireless system construction is available, because the single owner decides and conducts the equipment installation in their own facility. On the other hand, in the small community grids, such as a big mall, university and multi-vender integrated manufacturing farm, various and different types of the sensor terminals and the mobile terminals are gathering at the same place. In such a small community, heterogeneous and cognitive wireless sensor networks and several types of smart grid equipment are installed. Small number of wireless sensors of single network is distributed in the wide area through different groups of networks, like sandwich structure. Then, it becomes difficult to establish wide area sensor networks by using heterogeneous wireless sensor terminals, because the sensor density of reachable terminal becomes thin and the signal becomes unreachable. For the efficient and highly reliable use of the heterogeneous CRSN, we propose to establish the virtual radio free space transmission using the Radio on Fiber (RoF) technologies [2]-[4]. The conceptual illustration of the virtual radio free space transmission with radio agents is shown in Fig. 1. This infrastructure supports not only the CRSN but also the total operation of the heterogeneous radio systems cooperation by the Agent Based Communication Protocol (ABCP) [5]-[8]. In this paper, Section 2 describes the Radio Free Space Transmission using the RoF-MIMO (Multiple Input Multiple Output) system [9]-[28]. Also RoF-MIMO is categorized into four types, i.e. the Serial RoF-MIMO, the Parallel RoF-MIMO