Forum for Electromagnetic Research Methods and Application Technologies (FERMAT) 1 Abstract—The paper studies two resource allocation strategies (GRID, anti-EMI) for Multi-User Orthogonal Frequency Division Multiple Access (MU OFDMA) systems. These strategies are evaluated after being compared with the Round Robin and the Fractional Frequency Reuse (FFR) strategy in terms of mean throughput and mean dissipated power for 1, 2 and 5 allocated subcarrier frequencies per mobile terminal (MT) and algorithmic complexity. All investigated strategies assign resources without Channel State Information (no CSI), while both GRID and anti-EMI inherently combat Co-Channel Interference (CCI); hence they enhance mean throughput. Simulations indicate that GRID outperforms Round Robin and FFR in all scenarios into consideration and competes the anti-EMI strategy in various network orientations. The latter is justified especially for highly populated scenarios (i.e. 50% probability failure and 2 subcarriers per MT). As for the FFR strategy, simulations verify that the spectral efficiency is not the optimum in irregular-shaped cell networks, which has been verified in studies on regular- shaped cell networks as well. Finally, the platform can inherently spare around the 70% of the maximum available power. Index Terms—OFDMA, Resource Allocation Management, FFR, Inter-Cell Interference Cοordination. I. INTRODUCTION Like all infrastructure-based wireless networks, a multi- cellular network is a cluster of coordinated base stations (BS, fixed access points) which ensures access for the mobile terminals to a backbone wired network with a single-hop routing. Even though from the financial and practical perspective it is not easily deployed, it is preferred over an ad- hoc network because it can enhance spectral efficiency thanks to frequency reuse, supports higher data rates, while also decreases delay and losses. However, the tendency of the MTs to further increase in number [1], the fast ubiquity of the new technologies along with the digital nomadic lifestyle resulted in a rather scarce spectrum and amplified the need for enhanced spectral efficiency and throughput, judicious exploitation of the available resources and interference mitigation. To deal with the aforementioned issues, this study focuses primarily on multiple access schemes and anti-jamming resources management (PHY, MAC) that are both based on the Orthogonal Frequency Division Multiplexing (OFDM) scheme [2]. This scheme has been widely taken into consideration especially for the last two technology generations, that is to say 3G and 4G, as in the case of IEEE standard-based technologies: WiMAX (802.16) [3], Bluetooth (802.15.1) [4], WiFi (802.11) [5] and WRAN (802.22) [6], and has been scheduled to be included in the next to come technology era (i.e. 5G). Inherently, OFDM enhances spectral efficiency due to the orthogonality between the adjacent subcarriers and can combat fading (owing to multipath and shadowing) by dividing a fast fading channel into flat fading narrowband sub- channels. If the aforementioned characteristics are combined with the multi-user diversity in frequency domain (i.e. in MU- OFDMA access scheme: different terminals experience a different channel quality and, therefore, a terminal is assigned a good-quality channel) [7], then the throughput challenge may be addressed. The effectiveness of the multiple access scheme has proved to be high, which is also witnessed by the recent scientific efforts to implement it on the Carrier Sense Multiple Access/ Carrier Aggregation (CSMA/CA) of LAN topologies [8]-[14]. OFDMA [15] cannot be easily implemented even though it is simple in principle, because radio resources are scarce to find, interference is still present (i.e. Co-Channel Interference, CCI), the MTs have different Quality of Service (QoS) requirements, etc.. If efficient On the Performance Evaluation of Two Novel Fractional Frequency Reuse Approaches for OFDMA Multi-User Multi-Cellular Networks Maria A. Seimeni (1) , Georgios I. Tsivgoulis (1) , Panagiotis K. Gkonis (1) , Dimitra I. Kaklamani (1) , Iakovos S. Venieris (1) and Christos A. Papavassiliou (2) (1) National Technical University of Athens, School of Electrical and Computer Engineering, 9 Heroon Polytechneioy str, Zografou, Athens, Greece (Email: mseimeni@icbnet.ntua.gr, gtsivgou@icbnet.ece.ntua.gr, pgkonis@esd.ntua.gr, dkaklam@mail.ntua.gr, venieris@cs.ntua.gr) (2) Electrical and Electronic Engineering, Imperial College, South Kensington Campus, London SW7 2AZ, England (Email: c.papavas@imperial.ac.uk)