Dynamic Cyclic Prefix Adjustment for Satellite OFDM Interference
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Solution Overview
Problem
The existing OFDM technology struggles in satellite communication systems due to high satellite movement speeds, leading to inter-symbol interference and inter-carrier interference, which results in poor signal transmission quality and stability, as the conventional OFDM symbols are not optimized for satellite communication scenarios.
Innovation Solution
The proposed method involves determining a dynamic CP length and CS length for OFDM symbols based on carrier attribute information, such as subcarrier spacing, beam identifier, and beam elevation angle, to adjust the OFDM symbol structure and avoid interference, thereby improving resource utilization and reducing bit error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional OFDM symbols are used in satellite communication systems, then the system can achieve wide coverage and long communication distance, but inter-symbol interference and inter-carrier interference occur due to high satellite movement speeds, resulting in poor signal transmission quality
Solution Approach 1:
The patent applies dynamics by making the CP length configurable and adaptable rather than fixed. The cyclic prefix length is adjusted based on satellite movement speed and channel conditions, allowing the OFDM symbol structure to dynamically adapt to the high-mobility satellite communication environment, thereby reducing inter-symbol interference while maintaining signal transmission quality
Solution Approach 2:
The patent changes key parameters of the OFDM symbol structure, specifically the cyclic prefix length and subcarrier spacing, to optimize performance for satellite communication. By modifying these parameters according to satellite movement characteristics and channel conditions, the system achieves better resistance to inter-symbol interference and inter-carrier interference compared to conventional fixed-parameter OFDM
2Reliability
If the CP length is increased to avoid inter-symbol interference, then signal transmission stability improves, but resource utilization decreases
Solution Approach 1:
The patent implements dynamic CP length adjustment based on satellite movement speed and channel conditions. When satellite speed is high or channel delay spread is large, the CP length is increased to prevent inter-symbol interference. When conditions are favorable, the CP length is reduced to improve resource utilization. This dynamic adaptation resolves the contradiction between reliability and productivity
Solution Approach 2:
The patent changes the CP length parameter adaptively rather than using a fixed value. By adjusting this critical parameter based on operational conditions, the system achieves optimal balance between signal transmission stability and resource efficiency, preventing both inter-symbol interference and unnecessary resource waste
3Device complexity
If the OFDM technology is applied directly from terrestrial communication to satellite communication, then implementation complexity is reduced, but the transmission requirement of the satellite communication system cannot be met due to high moving speed and Doppler effect
Solution Approach 1:
The patent modifies key OFDM parameters including subcarrier spacing and cyclic prefix length to suit satellite communication requirements. These parameter changes address the high movement speed and Doppler effect characteristics of satellite systems while maintaining the overall OFDM framework, thus achieving a balance between implementation simplicity and transmission quality
Solution Approach 2:
The patent segments the OFDM parameter configuration into different sets optimized for different satellite communication scenarios. By providing multiple parameter configurations that can be selected based on specific operational conditions, the system maintains implementation simplicity while adapting to varying satellite movement speeds and channel conditions
Data Source
AI summary
Example signal transmission methods based on satellite communication and apparatus are described. One example method includes: obtaining, by a communication device, carrier attribute information corresponding to a target carrier used to transmit an orthogonal frequency division multiplexing (OFDM) symbol. The carrier attribute information of the target carrier includes subcarrier spacing. The communications device determines a cyclic prefix (CP) length of the OFDM symbol based on the carrier attribute information of the target carrier and a preset correspondence between carrier attribute information and the OFDM symbol. The CP is used to carry first data. The first data is data in the OFDM symbol.