Terminal SSB–PRACH Time Alignment for High-Frequency FDD
Solution Overview
Problem
In high-frequency bands exceeding 52.6 GHz, such as FR4, phase noise and propagation loss increase, and the system becomes more sensitive to peak-to-average power ratio (PAPR) and power amplifier nonlinearity, necessitating a larger sub-carrier spacing (SCS) or single carrier waveform. The increased number of SSB indices and PRACH Occasions (ROs) leads to signaling overhead, which existing technologies struggle to manage efficiently.
Innovation Solution
The solution involves configuring SSBs and ROs in the same positions in the time direction using Frequency Division Duplex (FDD), allowing for efficient allocation of SSBs and ROs without increasing overhead, even with a higher number of beams, by mapping SSBs and ROs onto the same symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of SSB indices is increased to cover more beams in high-frequency bands, then the beam coverage capability is improved, but the signaling overhead for SSBs and PRACH Occasions is increased
Solution Approach 1:
The patent merges the configuration information of multiple PRACH Occasions into a single unified indication. Instead of separately signaling each RO configuration, the base station indicates a single RO configuration that applies to multiple SSB indices, thereby reducing signaling overhead while maintaining the ability to support increased beam coverage through higher SSB index counts
Solution Approach 2:
The patent creates a universal PRACH Occasion configuration that serves multiple SSB indices simultaneously. A single RO configuration can be associated with multiple SSBs, allowing the same time-frequency resource pattern to be reused across different beams, which reduces the total signaling required while supporting expanded beam coverage
2Productivity
If Frequency Division Duplex (FDD) is used to configure SSBs and ROs in the same time positions, then the resource allocation efficiency is improved, but the complexity of managing frequency resources is increased
Solution Approach 1:
The patent segments the frequency spectrum into distinct uplink and downlink portions using FDD, allowing SSBs and ROs to occupy the same time positions without interference. By dividing the frequency resources into separate bands, the system achieves efficient time-aligned resource allocation while managing frequency complexity through clear spectral separation
Data Source
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AI summary
A terminal receives SSB in a different frequency band different from a frequency band including one frequency range or a plurality of frequency ranges, and transmits a preamble in PRACH Occasion (RO) . The SSB and the RO are allocated to a same position in a time direction using frequency division duplex.