Sensing-Based Dynamic Spectrum Sharing in Integrated Wireless Sensor and Cognitive Satellite Terrestrial Networks

Abstract

This paper presents a cognitive satellite communication based wireless sensor network, which combines the wireless sensor network and the cognitive satellite terrestrial network. To address the conflict between the continuously increasing demand and the spectrum scarcity in the space network, the cognitive satellite terrestrial network becomes a promising candidate for future hybrid wireless networks. With the higher transmit capacity demand in satellite networks, explicit concerns on efficient resource allocation in the cognitive network have gained more attention. In this background, we propose a sensing-based dynamic spectrum sharing scheme for the cognitive satellite user, which is able to maximize the ergodic capacity of the satellite user with the interference of the primary terrestrial user below an acceptable average level. Firstly, the cognitive satellite user monitors the channel allocated to the terrestrial user through the wireless sensor network; then, it adjusts the transmit power based on the sensing results. If a terrestrial user is busy, the satellite user can access the channel with constrained power to avoid deteriorating the communication quality of the terrestrial user. Otherwise, if the terrestrial user is idle, the satellite user allocates the transmit power based on its benefit to enhance the capacity. Since the sensing-based dynamic spectrum sharing optimization problem can be modified into a nonlinear fraction programming problem in perfect/imperfect sensing conditions, respectively, we solve them by the Lagrange duality method. Computer simulations have shown that, compared with the opportunistic spectrum access, the proposed method can increase the channel capacity more than 20% for Pav=10dB in a perfect sensing scenario. In an imperfect sensing scenario, Pav=15 dB and Qav=5 dB, the optimal sensing time achieving the highest ergodic capacity is about 2.34 ms when the frame duration is 10 ms.

Hybrid Satellite–Terrestrial Networks toward 6G: Key Technologies and Open Issues

“…In recent years, several works have been presented on spectrum sharing [ 100 , 104 , 105 , 106 , 107 , 108 , 109 , 110 ] and cognitive HSTNs, focusing on underlay [ 101 ], overlay [ 102 ], broadband cognitive radio schemes [ 111 ], energy efficiency [ 112 , 113 , 114 ], power allocation and control [ 99 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 ], performance evaluation and optimization [ 123 , 124 , 125 , 126 , 127 ], ergodic capacity [ 128 ], outage analysis [ 129 , 130 , 131 ], the impact of imperfect channel state information (CSI) [ 132 , 133 ], interference [ 134 ], and hardware impairment [ 133 , 135 , 136 ]. Figure 5 shows a cognitive HSTN with cognitive satellite–terrestrial radios (CSTR).…”

“…A sensing-based power allocation scheme for an integrated wireless sensor network-cognitive HSTN was introduced in [ 108 ]. Perfect and imperfect sensing scenarios for seamless channel access of the cognitive satellite’s secondary user were considered.…”

A Novel Dynamic Spectrum-Sharing Method for GEO and LEO Satellite Networks

“…Therefore, the next generation satellite system require significantly high spectral efficiency to address the spectrum scarcity problem between GEO system and LEO system. In order to achieve this objective, different satellite systems need to coexist within the same spectrum, which means that more interference may occur between these two satellite systems [1]- [3]. Recently, cognitive radio (CR) has received great attention as a promising solution to the inadequacy of The associate editor coordinating the review of this manuscript and approving it for publication was Haipeng Yao .…”