SSB Indexing Schemes for DRS Transmission Windows
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Solution Overview
Problem
Current wireless communication systems, particularly in LTE and NR technologies, face challenges in efficiently managing synchronization signal block (SSB) indexing schemes, especially when dealing with more than 64 candidate SSB positions, which affects cell timing determination and reliability, especially in unlicensed frequency bands with high contention and lower reliability.
Innovation Solution
Implementing either a consecutive or non-consecutive indexing scheme for SSBs within the discovery reference signal (DRS) transmission window, where SSBs are indexed in ascending order, allowing for more than 64 candidate SSB positions, enabling the base station to transmit SSBs in later portions of the window even if initial access is denied, reducing latency and improving reliability by allowing UE to combine SSBs within the same window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional indexing scheme limiting to 64 candidate SSB positions is used, then the system maintains simplicity in indexing management, but the reliability of cell timing determination deteriorates in unlicensed frequency bands with high contention
Solution Approach 1:
The patent divides the SSB indexing into two separate schemes: a first indexing scheme for the first set of SSB positions and a second indexing scheme for the second set of SSB positions. This segmentation allows the system to handle more than 64 candidate positions while maintaining manageable complexity through structured organization of indexing rules for different position sets.
Solution Approach 2:
The patent implements dynamic indexing where the indexing scheme adapts based on the SSB position set being used. The first and second indexing schemes can be selectively applied depending on which set of SSB positions is being referenced, allowing the system to flexibly handle varying numbers of candidate positions beyond the fixed 64-position limit while maintaining operational simplicity.
2Loss of time
If the base station transmits SSBs only in initial portions of the DRS transmission window, then the access procedure completes quickly, but the latency increases when initial access is denied due to contention in unlicensed bands
Solution Approach 1:
The patent prepares multiple SSB positions in advance within the DRS transmission window, with both first and second indexing schemes pre-configured. This allows the base station to have ready-made alternatives for SSB transmission positions, so when initial access attempts are denied due to contention, the UE can quickly switch to alternative positions without significant delay, thus reducing access latency while maintaining reliability.
Solution Approach 2:
The patent enables continuous SSB transmission opportunities throughout the DRS transmission window by defining multiple candidate positions with different indexing schemes. Instead of stopping after initial positions are denied, the system maintains continuous access attempts across different SSB positions, ensuring that useful access actions continue uninterrupted until successful connection is established.
3Adaptability or versatility
If more than 64 candidate SSB positions are supported, then the system improves adaptability to handle contention in unlicensed bands, but the complexity of managing and determining indices increases
Solution Approach 1:
The patent segments the candidate SSB positions into distinct first and second sets, each with its own indexing scheme. This segmentation allows the system to support more than 64 total positions while keeping each individual indexing scheme manageable and understandable, reducing the perceived complexity through structured division of the position space.
Solution Approach 2:
The patent creates a universal indexing framework that can handle both the first set and second set of SSB positions through standardized indexing procedures. The UE and base station can universally apply the appropriate indexing scheme based on which position set is being used, providing multi-functional capability to handle various contention scenarios without requiring completely separate management mechanisms for each case.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may detect a synchronization signal block (SSB) within a discovery reference signal (DRS) transmission window that includes more than 64 candidate SSB positions; determine an index value of the SSB based at least in part on an indexing scheme for SSBs that are included in the DRS transmission window, wherein the indexing scheme includes one of a consecutive indexing scheme or a non-consecutive indexing scheme; and determine a cell timing based at least in part on the index value. Numerous other aspects are described.