Random Access Occasion Identification in Non-Terrestrial Networks
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Solution Overview
Problem
In Non-Terrestrial Network (NTN) communication, existing random access (RA) techniques struggle to identify different RA occasions (ROs) due to long Round Trip Time (RTT), making it difficult for base stations to calculate Timing Advance (TA) and Random Access-Radio Network Temporary Identifier (RA-RNTI), and increasing the average waiting time for user equipment (UE) to transmit preambles.
Innovation Solution
The method involves determining and transmitting RO configuration information, including association relations between ROs and corresponding frequency resources or available preambles, to enable the UE to perform random access without increasing the waiting time, even if the time interval between ROs is less than the maximum RTT difference, allowing the network to accurately determine each RO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing RO design for terrestrial network is used in NTN communication, then the RO configuration is simple, but the base station cannot identify different ROs due to long RTT duration
Solution Approach 1:
The patent segments the RO identification process by associating each RO with specific frequency resources and preambles. Instead of relying solely on time separation, the system divides the identification space into multiple dimensions (frequency resources, preambles, and time), allowing the base station to identify different ROs even when their time intervals are shorter than the RTT duration.
2Measurement precision
If the time interval between ROs is increased to accommodate RTT duration, then the base station can identify different ROs, but the average waiting time for UE to transmit preamble increases
Solution Approach 1:
The patent introduces additional dimensions for RO identification beyond time. By associating ROs with specific frequency resources and preambles, the system creates a multi-dimensional identification space. This allows ROs to be distinguished even when their time intervals are short, as the frequency and preamble dimensions provide additional discrimination capabilities.
3Loss of time
If multiple ROs are configured within the maximum RTT difference time, then the UE waiting time is reduced, but the base station cannot calculate TA and RA-RNTI accurately
Solution Approach 1:
The patent implements a feedback mechanism where the base station receives preambles on specific frequency resources and uses the associated RO configuration information to determine the correct RO. This feedback loop enables accurate TA and RA-RNTI calculation even when multiple ROs are configured within the maximum RTT difference time, as the frequency resource and preamble associations provide the necessary identification information.
Data Source
AI summary
An RO indication method and apparatus, an RO determination method and apparatus, a storage medium, a base station and a terminal are provided. The RO indication method includes: determining RO configuration information which includes at least one of followings: an association relation between ROs and corresponding frequency resources where the ROs are located respectively, and an association relation between ROs and corresponding available preambles; and transmitting the RO configuration information to a UE. By the embodiments of the present disclosure, a network is able to determine an RO of a UE without considering influence caused by a maximum difference time of RTT and increasing an average waiting time for the UE to transmit a preamble.