MBSFN Subframe Cyclic Prefix Configuration for LTE-A Coverage
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Solution Overview
Problem
The LTE-Advanced system faces challenges in improving throughput and interference coordination among cells, as existing reference signals are overhead and not optimized for all scenarios, particularly in multicast broadcast single frequency network subframes.
Innovation Solution
The use of a Multicast Broadcast Single Frequency Network (MBSFN) subframe as a user physical resource in the LTE-Advanced system, where OFDM symbols except those of the PDCCH adopt the same cyclic prefix as subframe 0, ensuring unified cyclic prefix across cells for consistent coverage, and the common reference signal is transmitted only in the first two symbols of the MBSFN subframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MBSFN subframe is used as user physical resource in LTE-A system, then system throughput is improved, but coverage consistency may be compromised due to different cyclic prefix configurations
Solution Approach 1:
The patent applies local quality by configuring the cyclic prefix differently for different parts of the MBSFN subframe. Specifically, the first two OFDM symbols (carrying PDCCH) use normal cyclic prefix while subsequent symbols (carrying PDSCH) use long cyclic prefix. This localized differentiation allows the subframe to serve dual purposes: maintaining coverage consistency for control signals while enabling efficient data transmission for user traffic.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the eNodeB to flexibly configure which MBSFN subframes are used for user data transmission based on traffic conditions and cell coordination needs. The system can dynamically switch between using MBSFN subframes for broadcast/multicast traffic versus unicast user traffic, optimizing throughput while maintaining coverage consistency through the unified cyclic prefix configuration for PDSCH symbols.
2Stability of the object's composition
If unified cyclic prefix is adopted for MBSFN subframe, then parameter consistency is guaranteed, but flexibility in reference signal transmission is reduced
Solution Approach 1:
The patent resolves this contradiction by applying local quality to different symbol portions within the MBSFN subframe. The first two symbols use normal cyclic prefix for PDCCH transmission where reference signals are needed, while subsequent symbols use long cyclic prefix for PDSCH transmission. This localized differentiation maintains parameter consistency for data transmission while preserving reference signal transmission flexibility where needed.
Solution Approach 2:
The patent segments the MBSFN subframe into distinct functional portions: the first two OFDM symbols dedicated to PDCCH with normal cyclic prefix for control signaling and reference signals, and subsequent symbols dedicated to PDSCH with long cyclic prefix for user data. This segmentation allows each portion to have optimized parameters for its specific function, resolving the contradiction between overall parameter consistency and local transmission flexibility.
Data Source
Figure 1~2
AI summary
The present invention discloses a multicast broadcast single frequency network subframe. The multicast broadcast single frequency network subframe is used as a physical resource of a user transmission data channel; in the multicast broadcast single frequency network subframe, except symbols of a physical downlink control channel, other symbols adopt the same cyclic prefix as subframe 0 in a local cell. The present invention also discloses a user data channel transmission method and device, and a user physical resource determining device. By using the subframe, the transmission method and device, and the determining device, the performance of the LTE-A system can be improved.