Performance of Micro-Scale Transmission & Reception Diversity Schemes in High Throughput Satellite Communication Networks  
[PERSON]  
1 Radio and Satellite Communications Group, Division of Information Transmission Systems and Materials Technology, School of Electrical and Computer Engineering, National Technical University of Athens, Iron Polytechniou 9, GR-157 80 Athens, Greece; [EMAIL_ADDRESS] (A.Z.P. ); [EMAIL_ADDRESS] (C.I.K.) [PERSON]  
1 Radio and Satellite Communications Group, Division of Information Transmission Systems and Materials Technology, School of Electrical and Computer Engineering, National Technical University of Athens, Iron Polytechniou 9, GR-157 80 Athens, Greece; [EMAIL_ADDRESS] (A.Z.P. ); [EMAIL_ADDRESS] (C.I.K.) 2  
[PERSON]  
Correspondence: [EMAIL_ADDRESS], Tel: +30-210723842210022102210221022102210221022102210221022102210221022102210221022210221022102221022102221022210222102221022  
In site diversity scenarios, one or more ground stations communicate with the same satellite and therefore, the probability that all of the links simultaneously experience severe attenuation is smaller than having a single station. In general, the gain of a site diversity system increases with increasing the distance between the stations. Nonetheless, a considerable gain can be observed even when the distance between the stations is appreciably small, such as in [18; 19; 20; 21]. Such systems can be employed in enterprise scenarios such as (but not limited to) company headquarters, sports events, concerts or media events. In such cases, the stations can be deployed around the company buildings, a stadium, or a concert hall forming a micro-scale site diversity scheme. In cases where multiple stations are used, Multiple Input Multiple Output (MIMO) techniques could also be employed to improve the system's performance even further. Regarding the use of MIMO techniques in satellite communications, selection diversity is mostly preferred and implemented, however, by exploiting the knowledge of the channel conditions, the system performance can be further enhanced [22]. In the context of satellite communications, due to the use of massive, very costly Gateways (GWs) used for data forwarding, it is more likely to have multiple stations at the user premises than at the GW sites [23; 24; 25]; therefore, at frequency bands such as Ka-band and above, the use of Multiple Input Single Output (MISO) and Single Input Multiple Output (SIMO) techniques with multiple antenna configurations used at the user terminals seem a potential solution to mitigate the various non-desirable propagation effects. In a MISO system the uplink can be enhanced, while in a SIMO system the downlink, respectively. Multi-path effects at such high frequencies are insignificant and thus, in order to exploit the MIMO principle the benefits arising from the spatial inhomogeneity of the rainfall are more relevant. According to [22], system capacity can be increased for both SIMO and MISO cases provided that perfect knowledge of the channel state is available at the receiver and transmitter, respectively. The Channel State Information (CSI) from the user terminals can be extracted either through beacon signals and/or radiometers [26; 27], or by exploiting the pilot symbols used in the transmitted frames [28; 29]. Prior to designing a communication system with built-in FMTs, multi-dimensional rain attenuation time series synthesizers are essential in order to capture the spatio-temporal characteristics of the propagation effects due to rain. In [30], a multi-dimensional time series synthesizer based on stochastic differential equations has been presented, while in [31] a filter-based method. Both models are based on the main assumptions of the Masseng-Bakken model [32], i.e., that rain attenuation follows the log-normal distribution and the Gaussian underlined process has an exponentially decreasing auto-correlation function; both models use the Pearson's correlation coefficient to model the spatial correlation.