Propagation Delay Characteristics Analysis in LEO Satellite Multi-Beam Antenna Coverage

2013 ◽  
Vol 791-793 ◽  
pp. 1931-1935
Author(s):  
Ming Ma ◽  
Xi Luan ◽  
Bin Li ◽  
Jian Jun Wu
Keyword(s):  
Satellite Communications ◽  
Propagation Delay ◽  
Satellite System ◽  
Calculation Model ◽  
Propagation Delays ◽  
Characteristics Analysis ◽  
Leo Satellite ◽  
Communications System ◽  
Calculated Analysis

In this paper a calculation model of propagation delays of satellite beams is introduced for LEO multi-beam satellite communications system. Based on actual parameters and beam coverage patterns of the Iridium and Globalstar system, the maximum propagation delay differentials in several typical beams from the center to the edge of the satellites coverage are calculated. Analysis of these results can provide reference for analyzing the feasibility of LEO multi-beam satellite system compatible with uplink synchronization in LTE.

Narrow-Band Interference Suppression in Transform Domain in Tracking and Data Relay Satellite System

2011 ◽  
Vol 135-136 ◽  
pp. 643-648
Author(s):  
Ping Gong ◽  
Hui Jun Xie ◽  
Yu Peng Liu ◽  
Xing Cun Wu
Keyword(s):  
Treatment Process ◽  
Narrow Band ◽  
Interference Suppression ◽  
Median Filter ◽  
Satellite Communications ◽  
Satellite System ◽  
Transform Domain ◽  
Narrowband Interference ◽  
Matlab Simulation ◽  
Communications System

This paper use the methods of lapped transform to implement DSSS system narrowband interference suppression in lapped transform domain. Interference suppression in part, by improved median filter algorithm in a treatment process can locate and suppress interference, and it will not be activated in the absence of presence of interference, thus saving processing time. From the results of Matlab simulation, we can see the structure based on the analysis of lapping transform that has good performance in anti-narrowband interference, so it will be widely used in the tracking and relay satellite communications system.

Propagation Delay Difference Estimation for Initial Random Access in LTE Compatible Mobile Satellite Communications System

2013 ◽  
Vol 846-847 ◽  
pp. 647-650
Author(s):  
Cheng Mei Li ◽  
Jian Jun Wu ◽  
Xiao Ning Zhang ◽  
Xi Luan ◽  
Hai Ge Xing
Keyword(s):  
Estimation Method ◽  
Random Access ◽  
Satellite Communications ◽  
Propagation Delay ◽  
Satellite System ◽  
Satellite Systems ◽  
Access Channel ◽  
Geo Satellite ◽  
Mobile Satellite ◽  
Delay Difference

In this paper, a two-step propagation delay difference estimation method is proposed for LTE compatible multi-beam satellite systems to ensure the initial random access (RA). For GEO satellite system, there exists a large propagation delay difference, we cannot directly apply the LTE delay estimation method. To deal with this issue, we first divide a satellite beam into some layered small sub-areas according to the different delay difference values. Then, two types of Physical Random Access Channel (PRACH) preamble burst format are given. The detailed PRACH parameters are provided. Finally, simulations are performed and the results verify the availability of our proposed design.

CQI Prediction for Shadow Fading in LTE-Compatible GEO Mobile Satellite Communications System

2013 ◽  
Vol 756-759 ◽  
pp. 2137-2141 ◽  
Author(s):  
Ya Dan Zheng ◽  
Ming Ke Dong ◽  
Ye Jin ◽  
Jian Jun Wu
Keyword(s):  
Prediction Models ◽  
Moving Average ◽  
Adaptive Modulation ◽  
Satellite Communications ◽  
Satellite System ◽  
Prediction Performance ◽  
Adaptive Modulation And Coding ◽  
Shadow Fading ◽  
Mobile Satellite ◽  
Communications System

CQI(Channel Quality Indicator) is an essential indicator for AMC(Adaptive Modulation and Coding) technique in LTE. Due to the long delay of GEO satellite channel, CQI prediction is necessary to ensure effective AMC in LTE-compatible GEO mobile satellite communications system. The complete procedure and problem encountered when doing AMC in satellite system are introduced and the difficulties of prediction are analyzed. In order to obtain meaningful and feasible CQI prediction results, a complete prediction scheme is proposed. By using approximate CQI data which is smoothed and with only shadow fading influence, various prediction models are compared. Taking both computation complexity and prediction performance into account, two models, ARIMA (Autoregressive Integrated Moving Average) and Kalman filter are chosen to be applied in this scheme. Simulation results show that the prediction performance is very well with the proposed method, which can surely guarantee AMC performance.

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