SS Block Reference Signal Density for PBCH Demodulation
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently demodulating physical broadcast channel (PBCH) transmissions due to limited bandwidth and resource allocation, particularly during initial access procedures, where synchronization signals and reference signals share resources, leading to suboptimal channel estimation and demodulation.
Innovation Solution
The proposed solution involves configuring synchronization signal (SS) blocks to transmit synchronization signals and PBCH transmissions in distinct time resources, with demodulation reference signals (DMRS) being transmitted within PBCH time resources at a higher density outside the SS bandwidth, using tones that provide efficient demodulation with minimal resources, and employing different DMRS sequences or waveforms for each PBCH symbol to convey identification and timing information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If synchronization signals and PBCH transmissions share the same bandwidth resources, then resource allocation is simplified, but channel estimation accuracy deteriorates due to interference and limited reference signal density
Solution Approach 1:
The patent segments the PBCH transmission bandwidth into two distinct regions: an inner region that overlaps with synchronization signal bandwidth and an outer region that extends beyond it. Different reference signal density configurations are applied to each region, with higher density in the inner region and lower density in the outer region. This segmentation allows optimized channel estimation for each bandwidth portion without requiring uniform high reference signal density across the entire bandwidth.
Solution Approach 2:
The patent applies local quality by configuring reference signals with non-uniform density across different frequency regions. Specifically, the first set of reference signals is configured with higher density in the inner bandwidth region, while the second set of reference signals is configured with lower density in the outer bandwidth region. This local differentiation optimizes channel estimation accuracy where needed while reducing overall resource consumption.
2Measurement precision
If reference signal density is increased across the entire PBCH bandwidth, then channel estimation accuracy improves, but transmission overhead and resource consumption increase
Solution Approach 1:
The patent divides the reference signal resources into two distinct sets: a first set configured for the inner bandwidth region and a second set configured for the outer bandwidth region. This segmentation enables differential resource allocation, providing sufficient reference signal density for accurate channel estimation in the critical inner region while minimizing reference signal overhead in the outer region.
Solution Approach 2:
The patent implements local quality by applying different reference signal density configurations to different spatial (frequency) regions. The inner bandwidth region receives higher reference signal density for accurate channel estimation, while the outer bandwidth region uses lower density, thereby optimizing the balance between estimation accuracy and resource consumption.
3Productivity
If PBCH transmission bandwidth is extended beyond SS bandwidth, then coverage and data rate improve, but demodulation complexity increases due to broader frequency range
Solution Approach 1:
The patent segments the PBCH transmission into two bandwidth portions: an inner portion that overlaps with synchronization signal bandwidth and an outer portion that extends beyond it. This segmentation allows the UE to perform channel estimation separately for each portion using appropriately configured reference signals, simplifying the demodulation process compared to handling the entire extended bandwidth uniformly.
Solution Approach 2:
The patent applies local quality by configuring different reference signal parameters for different bandwidth regions. The inner bandwidth region uses one reference signal configuration while the outer bandwidth region uses another, allowing optimized demodulation for each region and reducing overall demodulation complexity despite the extended transmission bandwidth.
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AI summary
Methods, systems, and devices for wireless communication are described that provide for synchronization signal (SS) blocks in which synchronization signals and broadcast channel transmissions may be transmitted. Broadcast channel transmissions may be demodulated using SS transmissions, reference signal transmissions, or combinations thereof. Broadcast channel transmissions may be transmitted in a subset of SS block time resources, and synchronization signals may be transmitted in another subset of SS block time resources. Reference signals may be transmitted using tones within the broadcast channel time resources, and may be transmitted at a higher density for portions of the broadcast channel transmission bandwidth that are outside of the SS transmission bandwidth. Waveforms for reference signal transmissions, and information provided by reference signal transmissions may be provided.