Joint cooperative spectrum sensing and channel selection optimization for satellite communication systems based on cognitive radio

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Cognitive radio (CR) as a promising way to solve the spectrum scarcity allows exploitation of the shared frequency bands while guaranteeing acceptable interference to incumbent users in satellite communication systems. An improved spread slotted ALOHA (SSA) based on multi-user, multi-channel CR model applying to the satellite communications is proposed in this paper. To make full use of the detection information of satellite earth stations, a novel joint collaborative sensing method is used in the sensing phase. Moreover, a better throughput is achieved by using the improved SSA strategy in the transmission phase comparing with the traditional slotted ALOHA (SA). Theoretical analysis shows that the system performs better when SSA is adopted. Theoretical analysis and simulation results indicate that the sensing method used in this model outperforms the traditional "hard combining" strategy in the whole sensing process.

“…We suppose that the sample frequency in sensing phase is 6 MHz, i.e., f s = 6 MHz. We obtain the relationship between P f and P d from [7], which can be expressed as follows.…”

Section: Simulation Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A novel spread slotted ALOHA based on cognitive radio for satellite communications system

Jia

Wang

Yin

et al. 2016

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“…Each participant initially held the phone in hand, started the application, put it into the pocket and then started the walking. As in many other works [14,33,34], some parameters such as the initial walking direction are assumed to be known. To label the ground truth and compute the user heading estimation errors, we deployed a video to record the entire walking process of each participant.…”

Section: Methodsmentioning

confidence: 99%

Heading estimation fusing inertial sensors and landmarks for indoor navigation using a smartphone in the pocket

Deng

et al. 2017

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Principal component analysis (PCA)-based approach for user heading estimation using a smartphone in the pocket suffers from an inaccurate estimation of device attitude, which plays a central role in both obtaining acceleration signals in the horizontal plane and the ultimate global walking direction extraction. To solve this problem, we propose a novel heading estimation approach based on two unscented Kalman filters (UKFs) fusing inertial sensors and landmarks. The first UKF is developed for the recalibration of device attitude estimation. We mathematically derive the measurement equation connecting observed user heading from landmarks with the quaternion vector representing device attitude. To decrease the nonlinearity of the measurement equation and make the filter more robust, we deploy the difference between user heading derived from the landmark and estimation result of PCA-based approach as the observation variable. The second UKF is developed for user heading estimation fusing estimation results of PCA-based approach and observed user headings from landmarks. Besides, we develop a robust landmark identification method by exploiting the acceleration and device pitch patterns, while noisy barometers are no longer required as previous methods. Experiments show that the proposed landmark-aided user heading estimation approach may improve accuracy performance significantly, which is very useful for continuous indoor navigation.

“…Varshney put forward the concept of transmitting information and energy simultaneously and defined the capacity energy function for the first time [5]. Pulkit Grover proposed the model based on the electromagnetic induction principle and analyzed the noise coupling circuit with SWIPT [6][7][8][9][10] maximized the energy efficiency in spectrum sensing. Two transmission protocols based on power splitting relaying and mode adaptation were proposed in OFDM relaying SWIPT systems [11].…”

Section: Introductionmentioning

confidence: 99%

Subcarrier allocation based simultaneous wireless information and power transfer for multiuser OFDM systems

Liu

et al. 2017

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Most existing algorithms of simultaneous wireless information and power transfer (SWIPT) for orthogonal frequency division multiplexing (OFDM) systems are studied based on power splitting or time splitting, which lead to time delay and the decrease of subcarrier utilization. In this paper, a multiuser OFDM system with multichannel is established and the subcarriers are divided into two parts. One part is used for information decoding and the other part is used for energy harvesting. We maximize the sum rate of the users under the constraint of energy harvesting by optimizing the channel allocation and power allocation. By means of iterative calculation, an efficient subcarrier allocation algorithm is proposed. Simulation results demonstrate that the proposed algorithm converges fast and can achieve higher sum rate than the conventional algorithm.