Broadcast Channel Bandwidth Segmentation for Reduced-Capability UEs
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Solution Overview
Problem
Wireless communication systems struggle to manage broadcast channels effectively for user equipment (UEs) with varying bandwidth capabilities, leading to inefficiencies and degraded performance for UEs with reduced bandwidth capabilities.
Innovation Solution
UEs with reduced bandwidth capabilities monitor search space occasions in non-overlapping subbands and capture samples based on their bandwidth capability, while base stations repeat broadcast channels in specific periods and apply different scrambling to ensure detection and decoding, allowing UEs to decode both primary and secondary broadcast channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If base stations transmit broadcast channels using a single wide downlink bandwidth, then the system can support high data rates and wide bandwidth operations, but UEs with reduced bandwidth capabilities cannot effectively receive or detect the broadcast channels
Solution Approach 1:
The wide downlink bandwidth is divided into multiple non-overlapping subbands, each capable of being received by UEs with reduced bandwidth capabilities. The broadcast channel is segmented and transmitted across these subbands, allowing both wideband and narrowband UEs to access the broadcast channel effectively.
Solution Approach 2:
Different portions (subbands) of the broadcast channel are transmitted with different local qualities - specifically, each subband is optimized to be detectable by UEs with reduced bandwidth capabilities, while the aggregate provides wide bandwidth performance for capable UEs.
2Reliability
If the system uses repeated broadcast channel transmissions to improve detection reliability for reduced-capability UEs, then detection reliability improves, but the time required to detect the broadcast channel increases
Solution Approach 1:
The broadcast channel is transmitted periodically across multiple search space occasions within a detection period. This periodic transmission allows reduced-capability UEs to accumulate samples over time while maintaining reasonable detection time through the structured repetition pattern.
Solution Approach 2:
Multiple samples of the broadcast channel transmitted across different search space occasions are combined at the UE side. This merging of samples from multiple transmissions improves detection reliability by providing redundant information that can be processed together.
3Adaptability or versatility
If the system transmits broadcast channels in non-overlapping subbands for reduced-capability UEs, then bandwidth capability compatibility improves, but the device complexity for monitoring and processing multiple subbands increases
Solution Approach 1:
The monitoring process is segmented into discrete subband monitoring tasks. Each UE monitors specific subbands according to its capability, dividing the complex wideband monitoring into simpler, manageable subband-level operations that reduce processing complexity while maintaining compatibility.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive signaling that configures a downlink bandwidth for a broadcast channel transmission (e.g., a physical downlink control channel transmission). The UE may determine a bandwidth of the capability is less than the downlink bandwidth, and monitor search space occasions in a period to receive samples of the broadcast channel. The period and the search space occasions may be associated with a control resource set and a search space set. The UE may receive the samples in non-overlapping subbands of the bandwidth according to the bandwidth capability, and detect the broadcast channel based on the samples. The UE may additionally monitor repeated transmission occasions in the period based on detecting the broadcast channel to detect a second broadcast channel (e.g., a physical downlink shared channel).