Modified OFDM Frame Structure for Satellite Terrestrial Synchronization
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Solution Overview
Problem
Current wireless communication systems face challenges in accurately synchronizing OFDM symbols across multiple transmitters and receivers, especially in non-terrestrial networks, which affects signal orthogonality and interference mitigation, particularly in scenarios where satellite and terrestrial signals share the same spectrum resources.
Innovation Solution
A modified OFDM frame structure is introduced, allowing for flexible subcarrier spacing and cyclic prefix configuration, enabling groups of OFDM symbols to operate without cyclic prefixes between them, with common cyclic prefixes at the beginning of each group, and supporting different OFDM parameters for various bandwidth parts to enhance synchronization and interference management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclic prefix is inserted between every OFDM symbol to maintain orthogonality, then signal orthogonality is improved, but overhead increases and spectral efficiency deteriorates
Solution Approach 1:
The patent segments the OFDM symbol structure by grouping multiple OFDM symbols together and inserting cyclic prefix only at the beginning of each group rather than between every symbol. This segmentation approach maintains orthogonality within groups while reducing overall overhead, directly resolving the contradiction between reliability and quantity of substance.
Solution Approach 2:
The patent implements periodic insertion of cyclic prefixes at group boundaries rather than continuous insertion between every symbol. This periodic action pattern reduces the frequency of cyclic prefix insertion while maintaining signal orthogonality through proper group synchronization, addressing the trade-off between reliability and overhead.
2Reliability
If different OFDM parameters are used for satellite and terrestrial networks to optimize performance, then system robustness is improved, but spectrum sharing efficiency deteriorates
Solution Approach 1:
The patent enables dynamic configuration of OFDM parameters including subcarrier spacing and cyclic prefix length that can be adjusted based on whether the transmission is satellite or terrestrial. This dynamic adaptability allows optimal performance for each network type while maintaining spectrum sharing capability through coordinated parameter selection, resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent changes key OFDM parameters (subcarrier spacing, cyclic prefix length) to match different propagation characteristics of satellite versus terrestrial networks. By carefully selecting parameter combinations that accommodate both network types, the system achieves robustness for each while enabling efficient spectrum sharing through parameter coordination.
3Reliability
If cyclic prefix is inserted between every OFDM symbol to mitigate multipath propagation, then signal quality is improved, but transmission overhead increases
Solution Approach 1:
The patent segments the transmission into groups of OFDM symbols with cyclic prefix inserted only at group boundaries. This segmentation maintains multipath mitigation capability within each group while significantly reducing the total amount of cyclic prefix overhead, directly addressing the contradiction between reliability and loss of time.
Solution Approach 2:
The patent applies cyclic prefix protection partially rather than excessively, inserting it only where needed at group boundaries rather than between every symbol. This partial action approach provides sufficient multipath mitigation for signal quality while minimizing transmission overhead, resolving the contradiction between reliability and time loss.
Data Source
AI summary
An apparatus for transmitting and/or for receiving a signal in a wireless communication system according to an embodiment is provided. The signal is a data signal or is a positioning reference signal. The apparatus is configured to transmit and/or to receive the data signal or the positioning reference signal in a frame, wherein the frame comprises a plurality of OFDM symbols, wherein each of the plurality of OFDM symbols comprises a plurality of resource elements, wherein each of the plurality of resource elements of each of the plurality of OFDM symbols is assigned to one of a plurality of subcarriers. The plurality of OFDM symbols are arranged in the frame such that the frame comprises a plurality of groups, wherein each of the plurality of groups comprises two or more consecutive OFDM symbols of the plurality of OFDM symbols of the frame. No cyclic prefix is arranged between the two or more consecutive OFDM symbols of each of the plurality of groups.