Physical Broadcast Channel Repetition for Low-SINR Cell Acquisition
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Solution Overview
Problem
The reception of the physical broadcast channel (PBCH) in MBMS-dedicated cells is hindered by low Signal to Interference plus Noise Ratio (SINR), leading to demodulation failures under poor channel conditions, which affects the UE's ability to perform blind detection.
Innovation Solution
A method involving the transmission of the PBCH in multiple cell acquisition subframes with repeated symbols, utilizing a synchronization signal to access the MBMS-dedicated carrier, and adjusting the transmission based on downlink bandwidth configuration information to enhance reception probability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PBCH is transmitted in cell acquisition subframe, then UE can acquire cell information, but SINR is low leading to demodulation failure under poor channel conditions
Solution Approach 1:
The patent applies periodic action by transmitting the PBCH multiple times across different cell acquisition subframes (e.g., subframes 0, 4, 8, 12 within a radio frame). This periodic repetition allows the UE to accumulate signal energy over time, thereby improving the SINR and enabling successful demodulation even under poor channel conditions. The periodic transmission structure is configured according to the radio frame and subframe numbering system in LTE.
Solution Approach 2:
The patent implements continuity of useful action by ensuring that PBCH transmission continues across multiple subframes rather than a single transmission. The useful action (PBCH transmission) is maintained continuously across subframes 0, 4, 8, and 12, allowing the UE to continuously receive and accumulate signal information. This continuous transmission pattern maximizes the opportunity for successful reception by maintaining signal presence throughout the acquisition period.
2Reliability
If PBCH is transmitted only once in cell acquisition subframe, then transmission resources are saved, but reception probability is low
Solution Approach 1:
The patent employs periodic action by configuring PBCH transmission to occur in multiple cell acquisition subframes (specifically subframes 0, 4, 8, and 12 within each radio frame). This periodic repetition pattern increases the reception probability by providing multiple transmission opportunities, while the periodic structure ensures efficient use of transmission resources through systematic scheduling.
Solution Approach 2:
The patent applies parameter changes by adjusting the transmission configuration based on downlink bandwidth configuration information. The network device determines the number of cell acquisition subframes and their specific timing based on the detected downlink bandwidth, thereby optimizing the balance between transmission repetition count and resource utilization. This dynamic parameter adjustment ensures optimal reception probability for different network conditions.
3Reliability
If multiple cell acquisition subframes are used for PBCH transmission, then reception opportunities increase, but time consumption increases
Solution Approach 1:
The patent implements periodic action with a structured transmission pattern where PBCH is sent in subframes 0, 4, 8, and 12 within each radio frame. This periodic schedule provides multiple reception opportunities to improve detection success rate while maintaining predictable time intervals that facilitate UE scheduling and signal accumulation. The periodic structure balances reliability improvement with acceptable time consumption.
Solution Approach 2:
The patent applies parameter changes by dynamically configuring the number and timing of cell acquisition subframes based on downlink bandwidth detection. The network device adjusts the transmission parameters according to the detected bandwidth conditions, optimizing the balance between the number of transmission opportunities and the time intervals. This adaptive parameter configuration ensures efficient use of time resources while maintaining high reception reliability.
Data Source
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AI summary
This application provides a physical broadcast channel transmission method and a related apparatus. The method includes: A network device determines downlink bandwidth configuration information corresponding to a terminal device; the network device sends a first physical broadcast channel to the terminal device in a plurality of cell acquisition subframes based on the downlink bandwidth configuration information, where a time interval between every two adjacent cell acquisition subframes in the plurality of cell acquisition subframes is greater than or equal to 30 ms. When a bandwidth configuration value corresponding to the downlink bandwidth configuration information is greater than or equal to a first threshold, the plurality of cell acquisition subframes in which the first physical broadcast channel is sent include at least one first cell acquisition subframe. At least five symbols of the first physical broadcast channel are transmitted in the first cell acquisition subframe.