NB NR CORESET Frequency Alignment for Full CCE PDCCH Decoding
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Solution Overview
Problem
In narrowband new radio (NB NR) systems, the transmission of synchronization signals and PBCH blocks in channels narrower than 5 MHz, such as those used in railway communications, results in partial CCEs due to puncturing patterns, leading to degraded PDCCH channel estimation and decoding performance.
Innovation Solution
A method to determine the control resource set (CORESET) frequency location by aligning it with the low edge of a punctured synchronization signal block, avoiding partial CCEs through specific RB offset determination using PBCH parameters and signaled offsets, and employing different puncturing patterns to ensure full CCEs are used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If synchronization signal blocks are transmitted in narrowband channels with puncturing patterns, then the system can operate in channels narrower than 5 MHz, but partial CCEs are created leading to degraded PDCCH channel estimation and decoding performance
Solution Approach 1:
The patent applies local quality by making different parts of the synchronization signal block have different functions: the PSS and SSS regions are preserved for synchronization purposes, while the PBCH regions are punctured for control information transmission. This localized differentiation allows the system to maintain synchronization performance in narrowband channels while enabling PDCCH operation, resolving the contradiction between narrowband adaptability and PDCCH reliability.
Solution Approach 2:
The synchronization signal block is segmented into distinct regions (PSS, SSS, PBCH) with different puncturing patterns applied to each. The PSS and SSS are protected from puncturing to maintain synchronization, while PBCH regions are punctured to create full CCEs for PDCCH. This segmentation allows simultaneous achievement of narrowband operation and reliable PDCCH decoding.
2Productivity
If puncturing patterns are applied to synchronization signal blocks, then control information can be transmitted in narrowband channels, but channel estimation accuracy deteriorates due to partial CCEs
Solution Approach 1:
Different quality levels are assigned to different regions: PSS and SSS regions maintain full quality for accurate channel estimation, while PBCH regions accept puncturing for control information transmission. This local quality differentiation enables both control information transmission and accurate channel estimation to coexist in narrowband channels.
3Reliability
If the CORESET frequency location is aligned with the low edge of the punctured SSB, then full CCEs are ensured, but the flexibility in frequency resource allocation is reduced
Solution Approach 1:
The CORESET frequency location is preliminarily determined to be aligned with the low edge of the punctured SSB based on the known puncturing pattern. This preliminary alignment ensures full CCEs are formed before any dynamic resource allocation decisions are made, guaranteeing reliable PDCCH transmission while the flexibility is managed through higher-layer configuration parameters.
Data Source
AI summary
Various techniques are provided for a method including triggering, by a user equipment (UE), a resource block (RB) offset allocation determination, detecting, by the UE, at least one of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) in a received synchronization signal (SS) block (SSB), reading, by the UE, a physical broadcast channel (PBCH) parameter and a signaled offset from a master information block of a PBCH of the SSB, determining, by the UE, an RB offset based on the PBCH parameter and the signaled offset, and determining, by the UE, a control resource set frequency location based on the RB offset.