NTN CORESET Frequency Offsets to Prevent SSB Overlap
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Solution Overview
Problem
In non-terrestrial networks (NTNs), overlapping initial control resource sets (CORESETs) due to common frequency intervals for synchronization signal blocks (SSBs) lead to increased contention among user equipment (UEs) during random access procedures, resulting in potential transmission collisions.
Innovation Solution
Configuring an offset for the CORESET relative to the SSB based on the CORESET bandwidth and additional parameters, such as SSB index or user density, to ensure that CORESETs are disjoint in frequency, thereby preventing overlap and reducing contention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If common frequency intervals are used for SSBs to simplify network configuration, then device complexity is reduced, but CORESET overlap occurs leading to increased contention among UEs
Solution Approach 1:
The patent applies local quality by configuring different frequency offsets for CORESETs based on local conditions such as SSB index and user density. Specifically, UEs determine frequency offsets using formulas that incorporate local parameters (SSB index, CORESET bandwidth, user density indicators) to position their CORESETs in non-overlapping frequency intervals, thereby resolving contention while maintaining simplified overall network configuration.
2Productivity
If UEs perform random access procedures simultaneously to improve access speed, then productivity is increased, but transmission collisions occur due to CORESET overlap
Solution Approach 1:
The patent resolves transmission collisions by transitioning from time-domain only access to a frequency-time dimensional approach. UEs are allocated different frequency offsets for their CORESETs based on SSB index and user density, effectively distributing random access transmissions across multiple frequency dimensions. This allows simultaneous random access procedures without collisions, as each UE accesses the network in a unique frequency-time slot.
3Reliability
If frequency offsets are configured based on multiple parameters to eliminate CORESET overlap, then random access reliability is improved, but calculation complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring frequency offset formulas and parameters during network initialization. The gNB provides UE-specific configurations including SSB index, CORESET bandwidth, and user density indicators before random access procedures begin. UEs then directly apply these pre-configured parameters to calculate their frequency offsets using standardized formulas, eliminating the need for complex real-time calculations during actual random access execution.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. A non-terrestrial network (NTN) device (e.g., a satellite, base station) may transmit, to a user equipment (UE), at a first frequency a synchronization signal block (SSB) that indicates a second frequency of a control resource set (CORESET) relative to the SSB, where the second frequency is based on one or more of: a CORESET bandwidth, a combination of a first parameter associated with a first portion of the SSB and a second parameter associated with a second portion of the SSB, or both. The EE may monitor the CORESET at the indicated second frequency for a downlink control channel transmission. The NTN device may transmit, to the EE, a downlink control channel transmission over the CORESET. The NTN device may transmit, to the EE, system information based on the downlink control channel transmission.