Abstract
The incorporation of cognitive radio (CR) techniques into satellite communication systems, has been considered as one of the most promising approaches to address the spectrum scarcity, which constitutes an advanced infrastructure known as cognitive satellite terrestrial network (CSTN). Due to the estimation error or feedback delay, perfect channel state information (CSI) of satellite and/or terrestrial links in CSTNs are normally unavailable. This paper investigates the effect of imperfect CSI on the performance of CSTN, where a secondary satellite network coexists with a primary terrestrial network by employing the underlay cognitive mechanism according to which the satellite user is allowed to access the licensed spectrum without deteriorating the operation of terrestrial user. Specifically, we derive the analytical expressions for the outage probability and ergodic capacity of the cognitive network, which provides an efficient approach to jointly evaluate the impacts of imperfect channel estimations for different links on the performance of considered network. Moreover, simple asymptotic outage probability formula in the high signal-to-noise ratio regime is presented to reveal the diversity order and coding gain of the CSTNs. Finally, numerical results are provided to confirm the validity of the theoretical analysis, as well as quantitatively analyze the effects of various system parameters on the performance of the CSTNs with CSI imperfection.
Highlights
Satellite communication is capable of providing seamless connectivity and high speed broadband access for worldwide users based on an anywhere-anytime paradigm, especially for users who allocate in the disaster, desert, and/or suburb areas [1]–[3]
PERFORMANCE EVALUATION we present a comprehensive investigation on the effect of imperfect channel state information (CSI) on the performance of cognitive satellite terrestrial network (CSTN) in terms of key performance metrics, including outage probability, ergodic capacity as well as asymptotic outage probability in the high SNR regime
The outage performance with imperfect CSI of satellite uplink gradually approaches toward the perfect CSI case with the increase of training symbol L, which can be explained by the fact that more training symbols L means more precise channel estimation at the satellite
Summary
Satellite communication is capable of providing seamless connectivity and high speed broadband access for worldwide users based on an anywhere-anytime paradigm, especially for users who allocate in the disaster, desert, and/or suburb areas [1]–[3]. Due to the explosive growing demand for broadband satellite services in recent years, the licensed spectrum of satellite networks seems to be insufficient to meet the forthcoming requirement. Given this fact, exploring new insights and architectures into the utilization of spectrum in satellite communications have challenged the traditional spectrum management approaches [4].
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