Broadcast Channel Repetition Resource Mapping for MTC Coverage
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Solution Overview
Problem
Current wireless communication systems face challenges in providing adequate coverage enhancements for broadcast signaling, particularly for Machine-Type Communications (MTC) devices, which require significant coverage enhancements due to severe propagation losses, and existing designs may not meet the required coverage levels in all deployment scenarios.
Innovation Solution
The proposed solution involves resource mapping techniques for transmitting repeated broadcast channel (PBCH) signals across multiple sub-frames and sub-carriers, including partial repetitions and correlations at the User Equipment (UE) to determine the presence of broadcast channel repetitions, optimizing resource utilization and coverage enhancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If broadcast channel repetitions are transmitted across multiple sub-frames and sub-carriers to enhance coverage for MTC devices, then coverage enhancement is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The broadcast channel repetitions are segmented across multiple sub-frames and sub-carriers, allowing the signal to be distributed over different time and frequency resources. This segmentation enables MTC devices to accumulate signal energy across multiple resources, improving coverage while the distributed nature optimizes resource utilization by avoiding concentration of resources in a single location.
Solution Approach 2:
The patent extends the transmission of broadcast channel repetitions into multiple dimensions - specifically time (across sub-frames) and frequency (across sub-carriers). By utilizing these additional dimensions, the system achieves coverage enhancement through signal accumulation without proportionally increasing resource consumption in any single dimension, thereby maintaining resource utilization efficiency.
2Productivity
If partial repetitions are mapped onto subsets of sub-carriers, then spectral efficiency is improved, but detection reliability worsens
Solution Approach 1:
The patent implements partial repetitions by mapping broadcast channel signals onto subsets of sub-carriers rather than all available sub-carriers. This partial action approach improves spectral efficiency by leaving some sub-carriers available for other purposes while still providing sufficient repetition instances for reliable detection through correlation operations at the receiver.
Solution Approach 2:
The system employs correlation-based detection where the receiver correlates received signals with expected repetition patterns to determine the presence and content of broadcast channel repetitions. This feedback mechanism allows reliable detection even when only partial repetitions are transmitted, as the correlation process can identify the signal presence and extract information from the available repeated instances.
Data Source
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Figure 4a
AI summary
Methods and apparatus are provided for a base station to transmit repetitions of broadcast information and for a UE to detect the broadcast information. In a first method, the base station maps each repetition in a respective quadruple of subframe symbols while accounting for a possible different number of available sub-carriers among quadruplets of subframe symbols. In a second method, the base station maps the repetitions successively in available sub-carriers. For intermittent transmissions of repetitions, the UE can use the mapping structure of the repeated broadcast information to determine an existence of a transmission.