Satellite SSB Beam Positioning and PCID Segmentation
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Solution Overview
Problem
Satellite communication systems face challenges in synchronization signal design due to strong mobility, severe fading, and high power consumption, as existing downlink transmission technologies are not applicable and require efficient resource utilization and accurate synchronization detection.
Innovation Solution
A method for transmitting downlink synchronization signal blocks is designed, where the position and beam direction of synchronization signal blocks (SSBs) are determined and sent, with SSBs configured to use the same time-frequency domain resources across all beams, and the number of repetitions indicated through primary and secondary synchronization sequences, facilitating improved detection accuracy and resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one PCID covers multiple cells or one cell with multiple beams, then the device complexity is reduced, but the measurement precision of beam identification deteriorates
Solution Approach 1:
The patent segments the PCID space by introducing a two-layer identification mechanism: PCID for cell-level identification and SSB index for beam-level identification. This segmentation allows one PCID to cover multiple beams while the SSB index provides precise beam differentiation, resolving the contradiction between reduced complexity and maintained precision.
Solution Approach 2:
The patent adds another dimension to the identification system by introducing the SSB index as a secondary identification layer. Instead of relying solely on PCID for both cell and beam identification, the system uses PCID for the first dimension (cell) and SSB index for the second dimension (beam), enabling efficient multi-beam support without sacrificing identification accuracy.
2Measurement precision
If beam switching is performed with layer 1 switching, then the beam identification precision is improved, but the device complexity increases
Solution Approach 1:
The patent segments the switching functionality into two distinct layers: layer 1 switching for beam selection based on SSB index, and layer 3 switching for cell reconfiguration based on PCID. This segmentation allows precise beam identification through layer 1 switching while avoiding the complexity of full layer 1 switching for cell operations, which are handled at the simpler layer 3.
3Measurement precision
If SSBs are transmitted with repeated sequences, then the synchronization detection accuracy is improved, but the resource utilization deteriorates
Solution Approach 1:
The patent applies partial repetition of SSB sequences within a burst set, where not all SSBs are identical but a subset provides repetition for detection. This partial repetition approach achieves sufficient synchronization detection accuracy while minimizing redundant resource consumption compared to complete repetition of all SSBs.
Solution Approach 2:
The patent changes the sequence parameters of SSBs by applying different cyclic shifts to different SSBs within the same burst set. This parameter variation allows the system to maintain detection accuracy through correlation processing while reducing resource usage by avoiding complete sequence duplication, as the cyclically shifted versions provide diversity without full redundancy.
Data Source
Figure 1A
Figure 1B~2
Figure 3~4
AI summary
This disclosure provides a signal sending method, a signal receiving method, a network device and a terminal. The signal sending method includes: determining a position and beam direction of a synchronization signal block SSB to be sent; sending the SSB according to the determined position and beam direction of the SSB.