Physical Broadcast Channel Repetition for eMTC Coverage
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Solution Overview
Problem
Current wireless communication systems face challenges in enhancing downlink coverage for low-cost, low-data-rate user equipment (UEs) such as machine-type communication (MTC) devices, particularly in deep coverage holes and high-frequency deployments, where the physical broadcast channel (PBCH) coverage is limited.
Innovation Solution
The implementation of PBCH repetition techniques by base stations, where the PBCH is transmitted and repeated in specific subframes of a radio frame based on subframe configuration and system bandwidth, to enhance coverage for eMTC devices, including configurations for TDD and FDD systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PBCH is transmitted only once per radio frame, then transmission complexity is low, but coverage area is limited and unreliable in deep coverage holes
Solution Approach 1:
The patent applies periodic action by repeating the PBCH transmission at regular intervals across multiple subframes (e.g., every 4th subframe) within a radio frame. This periodic repetition ensures that the broadcast channel is transmitted multiple times, increasing the probability of successful reception in challenging coverage conditions while maintaining a structured, predictable transmission pattern that limits complexity.
Solution Approach 2:
The patent implements preliminary action by pre-configuring the repetition pattern and selecting appropriate subframes for PBCH transmission before the actual transmission occurs. The base station determines the repetition pattern in advance based on coverage requirements, and the UE is notified of this pattern, allowing both sides to prepare for the repeated transmissions without adding runtime complexity.
2Area of stationary object
If PBCH is repeated in multiple subframes, then coverage area is enhanced, but transmission resources are consumed
Solution Approach 1:
The patent applies partial action by repeating the PBCH only in specific, selected subframes rather than continuously in all subframes. The repetition pattern is designed to provide sufficient coverage enhancement while limiting the number of repetitions to an optimal level that balances coverage improvement with resource conservation. This partial repetition approach avoids excessive resource consumption while still achieving the desired coverage extension.
Solution Approach 2:
The patent segments the radio frame into multiple subframes and selectively assigns PBCH transmissions to specific segments (subframes) based on the determined repetition pattern. This segmentation allows the system to distribute PBCH transmissions across different time resources, enhancing coverage through spatial-temporal distribution while controlling the total resource consumption by not occupying all subframes.
3Adaptability or versatility
If PBCH repetition pattern is flexible and adaptive, then coverage optimization is improved, but system complexity increases
Solution Approach 1:
The patent implements parameter changes by allowing the PBCH repetition pattern to be configured with different parameters such as repetition interval, number of repetitions, and specific subframe selections. These parameters can be adjusted based on coverage requirements, frequency band, and network conditions. The base station determines appropriate parameter values and notifies the UE, providing adaptability without requiring complex real-time decision-making algorithms.
Solution Approach 2:
The patent introduces an intermediary mechanism through higher-layer signaling (RRC messages) that mediates between the base station's coverage requirements and the physical layer transmission parameters. The RRC signaling carries the repetition pattern configuration from the base station to the UE, acting as an intermediary layer that simplifies the complexity by separating the decision-making (base station) from the execution (physical layer transmissions and UE monitoring).
Data Source
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AI summary
Certain aspects of the present disclosure generally relate to wireless communications, and more specifically, to physical broadcast channel (PBCH) or other type channel repetition for enhanced machine type communication (eMTC). According to certain aspects, a method is provided for wireless communications by a base station (BS). The method generally includes determining a repetition pattern indicating subframes of a radio frame in which a channel is to be transmitted and transmitting the channel according to the determined repetition pattern.