scholarly journals Algorithm for frequency capture and rectification in a low-orbit satellite IoT communication network

2021 ◽  
Vol 18 (6) ◽  
pp. 7999-8023
Author(s):  
Jie Shen ◽  
◽  
Hanming Liu ◽  
Jing Wang ◽  
Xia Jia ◽  
...  
Keyword(s):  
Communication Network ◽  
Communication Systems ◽  
Satellite Communication ◽  
Doppler Frequency ◽  
Frequency Offset ◽  
Phase Offset ◽  
Frequency Capture ◽  
Simulation Results ◽  
The Doppler Effect ◽  
Offset Compensation

<abstract> <p>In satellite communication systems, due to relative motion between satellites and that between satellites and the ground, the resulting Doppler frequency offset adversely affects communication synchronization. In this research, Doppler frequency offset compensation and phase offset compensation method eliminate the influence of the Doppler effect on synchronization. The proposed algorithm divides frequency estimate into two steps, coarse and precision. Finally, the corresponding frequency offset and phase offset compensation are performed. The simulation results show that the demodulated output results after frequency offset and phase offset compensation agree well with the original modulation data, indicating that the algorithm is valid and accurate.</p> </abstract>

Improved Amplify-and-Forward Cooperative Scheme for Satellite Communication Systems

2012 ◽  
Vol 198-199 ◽  
pp. 1707-1711
Author(s):  
Min Jia ◽  
Xue Mai Gu ◽  
Qun Wu
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Cooperative Diversity ◽  
System Capacity ◽  
Wireless Communication Systems ◽  
Conventional System ◽  
Amplify And Forward ◽  
Cooperative Scheme ◽  
Simulation Results ◽  
Ber Performance

The technology of Amplify-and-forward cooperative diversity is popular for the cooperative communication system. And it can be applied when a communication terminal can’t communicate with other communication terminal directly. Moreover, this kind of scheme has been studied by the researchers for the application of terrestrial wireless communication systems. The conventional system presents that the power are equally distributed among all nodes. However, this algorithm can not be applied to satellites communication systems directly. Therefore, an improved Amplify-and-Forward cooperative scheme is presented in this paper, and the simulation results show that it can obtain the larger system capacity and better BER performance.

Frequency offset compensation for satellite communication system with CE-OFDM

2017 ◽  
Vol 14 (8) ◽  
pp. 93-104 ◽  
Author(s):  
Gaofeng Cui ◽  
Cheng Wang ◽  
Weidong Wang ◽  
Yinghai Zhang
Keyword(s):  
Communication System ◽  
Satellite Communication ◽  
Frequency Offset ◽  
Satellite Communication System ◽  
Offset Compensation

Forced-Retransmission Based Hybrid HARQ Scheme for GEO Satellite Communications

2013 ◽  
Vol 846-847 ◽  
pp. 651-654
Author(s):  
Ya Dan Zheng ◽  
Jian Bo Li ◽  
Yong Luo ◽  
Ming Ke Dong ◽  
Jian Jun Wu
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Satellite Communication ◽  
Satellite Communications ◽  
Hybrid Scheme ◽  
Satellite Communication System ◽  
Geo Satellite ◽  
Simulation Results

In this paper, a hybrid HARQ scheme was proposed by combing forced retransmission and traditional HARQ together, after analyzing the characteristics of satellite channel and the problem encountered when utilizing HARQ scheme in GEO satellite communication system. The forced retransmission can make a packet be correctly decoded more quickly and shorten the waiting delay. Meanwhile, to balance the delay and throughput, the proper parameters were given for the proposed hybrid scheme. Simulation results show that the proposed scheme performs well at decreasing the waiting delay, especially when SNR is low. The conclusion can be drawn that the proposed scheme can improve the HARQ performance in GEO satellite communication systems.

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