SSB-to-RO Mapping Across Beam Rounds for Reliable Random Access
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Solution Overview
Problem
The current 3GPP protocol increases overheads for terminal devices due to the need to determine multiple access occasions based on synchronization signal blocks (SSBs) in different beams, leading to inefficient resource utilization.
Innovation Solution
The method involves determining a first SSB in one of N rounds of SSB transmissions with distinct coverage areas and associating it with a unique random access channel (RO) resource, ensuring that SSBs with the same index in different rounds have different RO resources, and setting time intervals between these resources to be within predefined thresholds to optimize access performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device determines multiple access occasions based on SSBs in different beams according to current 3GPP protocol, then the access coverage and reliability are improved, but the overheads of the terminal device increase
Solution Approach 1:
The patent segments the access occasion determination process by introducing a network device that performs beam sweeping and SSB transmission separately from the terminal device's access occasion determination. The network device divides the coverage area into multiple beams and transmits SSBs in different rounds, while the terminal device only needs to determine one access occasion based on received SSB information, reducing its computational overhead while maintaining reliable multi-beam access coverage.
2Ease of manufacture
If SSBs with the same index in different rounds are associated with the same RO resource, then the resource allocation is simplified, but access conflicts increase and access performance deteriorates
Solution Approach 1:
The patent introduces a new dimension for resource allocation by associating SSBs with RO resources based on both their index and the round number in which they are transmitted. Instead of using only the SSB index (one-dimensional mapping), the system now uses a two-dimensional mapping where SSBs with the same index but different round numbers are associated with different RO resources. This resolves access conflicts while maintaining systematic resource allocation.
3Adaptability or versatility
If the time interval between RO resource and SSB is not constrained, then the resource flexibility is improved, but access performance and validity of RO resource for sending PRACH deteriorate
Solution Approach 1:
The patent optimizes access performance by constraining the time interval parameter between RO resources and their associated SSBs within a threshold value. This parameter change ensures that the RO resource remains valid for sending PRACH relative to the SSB timing, improving access performance while the overall system maintains flexibility through configurable threshold values and network-controlled timing parameters.
Data Source
AI summary
This application discloses an access occasion determining method. In an example of the method, the method comprises: determining a first SSB in an ith round of SSB transmission in N rounds of SSB transmissions, where coverage areas of the ith round of SSB transmission and a jth round of SSB transmission in the N rounds of SSB transmissions are different, N, i, and j are integers, and i is not equal to j; and determining a first RO resource associated with the first SSB, where SSBs that have a same index in the ith round of SSB transmission and the jth round of SSB transmission are associated with different RO resources.