Optimal Power Control in Cognitive Satellite Terrestrial Networks With Imperfect Channel State Information

Abstract

To address the spectrum scarcity in future satellite communications, employing the cognitive technique in the satellite systems is considered as a promising candidate, which leads to an advanced architecture known as cognitive satellite terrestrial networks. Power control is a significant research challenge in cognitive satellite terrestrial networks, especially when the perfect channel state information (CSI) of satellite or terrestrial links is unavailable because of the estimation error or feedback delay. In this context, we investigate the impact of imperfect CSI of both desired satellite link and harmful terrestrial interference link on the power control scheme in cognitive satellite terrestrial networks. By adopting a pilot-based channel estimation of satellite link and a back-off interference power constraint of terrestrial interference link, a novel power control scheme is presented to maximize the outage capacity of the satellite user while guaranteeing the communication quality of primary terrestrial user. Extensive numerical results quantitatively demonstrate the effect of various system parameters on the proposed power control scheme in cognitive satellite terrestrial networks with imperfect CSI.

Robust Chance-Constrained Secure Transmission for Cognitive Satellite–Terrestrial Networks

“…Let Ξ = {Z p , Z e , Z s , T} denote the collection of dual variables, where Z p ≽ 0, Z e ≽ 0, Z s ≽ 0 and T ≽ 0 are corresponding to the constraints (36b)-(36e), the Lagrangian of problem (36) His current research centers around 5G and beyond mobile communications, including topics such as massive MIMO, full-duplex communications, millimetre-wave communications, edge caching and fog networking, physical layer security, wireless power transfer and mobile computing, V2X communications, and of course cognitive radios. There are also a few other unconventional research topics that he has set his heart on, including for example, fluid antenna communications systems, remote ECG detection and Pei Xiao (SM'11) is a professor of Wireless Communications at the Institute for Communication Systems, home of 5G Innovation Centre (5GIC) at the University of Surrey.…”

“…In practical communication systems, the channel knowledge of PU and Eve is unavailable at the terrestrial BS since the PU and Eve are within the satellite network 4 [36]. Meanwhile, we assume that the CSI of SU is also unavailable to the terrestrial BS due to estimated and feedback errors.…”

On the Performance of Cognitive Satellite-Terrestrial Relay Networks with Channel Estimation Error and Hardware Impairments

“…Now, as pointed out earlier, only non-ideal CSI of both satellite and terrestrial links is known; thus, non-ideal channel gains need to be found before the performance evaluations. Hence, the channel can be modeled as [ 23 , 24 ] (we should note that this model has been proven and extensively used in existing works such as [ 23 , 24 ]), where and represent the practical and estimated fading coefficients, respectively, and are assumed to have combined ergodicity and denotes the estimation error, which is orthogonal to the channel estimate coefficient with modeling as a zero mean complex Gaussian distribution [ 23 ] with its variance: where is the length of training symbols and is the mean SNR of the training symbol for the transmitting link with HIs. Besides with the scale coefficient , presents the power of the pilot symbols, the total transmission power and the AWGN variance of the transmitting links.…”

“…Besides, owing to the time-varying character of terrestrial links, the availability of the perfect CSI cannot be obtained in practice, either. Currently, the issue of CEEs for the CSTRN has been studied in several works [ 23 , 24 ]. In [ 23 ], the impact of non-ideal CSI for both the harmful terrestrial interference link and desired satellite link on the power control scheme was investigated in the CSTRN.…”

“…Currently, the issue of CEEs for the CSTRN has been studied in several works [ 23 , 24 ]. In [ 23 ], the impact of non-ideal CSI for both the harmful terrestrial interference link and desired satellite link on the power control scheme was investigated in the CSTRN. In [ 24 ], the authors analyzed the secrecy performance of the primary satellite system in the CSTRN with the underlay scheme and imperfect CSI.…”