Terminal Initial Access Configurations for High-Frequency Bands
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Solution Overview
Problem
In high-frequency bands beyond 52.6 GHz, such as FR4, the increased phase noise, propagation loss, and sensitivity to peak-to-average power ratio (PAPR) and power amplifier nonlinearity pose challenges for reliable initial access, particularly in reducing the coverage of random access (RA) preambles due to shorter OFDM symbol lengths and limited cyclic shift amounts.
Innovation Solution
A terminal is configured to apply different initial access configurations, including specific formats for RA preambles, when operating in frequency bands other than FR1 and FR2, such as FR4. This involves adjusting the subcarrier spacing (SCS), preamble length, and PRACH configuration to maintain reliable initial access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a larger subcarrier spacing (SCS) is used in high-frequency bands (above 52.6 GHz), then the phase noise and propagation loss are reduced, but the OFDM symbol length and SS/PBCH block duration become shorter, decreasing the reachable range of RA preambles
Solution Approach 1:
The patent applies dynamics by making the preamble format configurable and adaptable to different frequency bands. The base station can dynamically select and notify the terminal of appropriate preamble formats (first format for FR1/FR2, second format for bands above 52.6 GHz) based on the operating frequency, allowing the system to optimize performance for each band rather than using a fixed format
Solution Approach 2:
The patent changes physical parameters of the RA preamble by defining different formats with distinct configurations. The second format specifically increases the preamble length and adjusts the cyclic prefix structure compared to the first format, directly addressing the coverage reduction issue in high-frequency bands while maintaining the benefits of larger SCS
2Reliability
If a larger subcarrier spacing (SCS) is used, then the phase noise is reduced, but the RA preamble length becomes shorter, limiting the cyclic shift amount and reducing the number of preamble patterns
Solution Approach 1:
The system dynamically adapts the preamble format based on frequency band. In high-frequency bands where larger SCS is used, the second format provides extended preamble length that enables sufficient cyclic shift amounts, thereby maintaining or increasing the number of available preamble patterns despite the larger SCS
Solution Approach 2:
The patent changes the temporal parameters of the preamble by defining the second format with increased length. This parameter change directly enables larger cyclic shift amounts and thus supports a greater number of distinct preamble patterns, counteracting the limitation imposed by larger SCS
3Reliability
If the OFDM symbol length is shortened due to larger SCS, then the phase noise is reduced, but the coverage of RA preambles is decreased due to propagation delay
Solution Approach 1:
The base station dynamically selects the appropriate preamble format based on the frequency band and notifies the terminal. In high-frequency bands, the second format with extended length is selected to compensate for propagation delay and maintain coverage, while still benefiting from the phase noise reduction of larger SCS
Solution Approach 2:
The patent directly addresses the coverage issue by changing the temporal parameters of the preamble in the second format. The extended preamble length and adjusted cyclic prefix structure provide sufficient time margin for propagation delay in high-frequency bands, maintaining coverage while utilizing the phase noise benefits of larger SCS
Data Source
AI summary
In a case of using a different frequency band that is different from a frequency band including one or a plurality of frequency ranges, a terminal applies initial access configurations including a format of an initial access signal, the format being different from that for the frequency band. The terminal transmits the initial access signal via an initial access channel set based on the applied initial access configurations.