SFN Transmission via SRS Measurements for Beam Selection
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Solution Overview
Problem
In wireless communications systems, synchronously transmitting downlink data from multiple cells in a single frequency network (SFN) can be challenging due to difficulties in identifying suitable transmit beams for neighbor cells, as the UE typically uses a single receive beam, which may not be optimal for each neighbor cell.
Innovation Solution
A serving cell configures neighbor cells to perform measurements on sounding reference signals (SRSs) received from the UE, allowing the serving cell and a subset of neighbor cells to determine suitable configurations for SFN transmission, including adding or excluding cells from the SFN cell group and selecting appropriate beams based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple cells synchronously transmit downlink data to a UE in an SFN, then the reliability of data reception is improved, but the difficulty of identifying suitable transmit beams for each neighbor cell increases
Solution Approach 1:
The patent introduces SRS measurements as an intermediary mechanism to facilitate beam identification. Neighbor cells measure the SRS signals transmitted by the UE to determine suitable transmit beams for SFN transmission, avoiding the complexity of direct beam identification while maintaining reliable data reception
Solution Approach 2:
The patent implements a feedback mechanism where measurement results of SRS signals are reported back to the serving cell. Based on these feedback measurements, the serving cell determines the configuration of SFN transmission, enabling adaptive beam selection that improves reliability while managing complexity
2Area of stationary object
If all neighbor cells participate in SFN transmission, then the coverage area is extended, but the throughput may be degraded due to suboptimal beam configurations
Solution Approach 1:
The patent applies local quality by allowing different neighbor cells to participate in SFN transmission based on their individual measurement results. Cells with optimal beam configurations for specific geographic areas are selected to transmit, ensuring high throughput in each local region while collectively extending coverage area
Solution Approach 2:
The patent implements dynamic cell selection for SFN transmission. The serving cell determines which neighbor cells participate in SFN based on real-time SRS measurement results, allowing the transmission group to be dynamically adjusted to optimize both coverage area and throughput according to current channel conditions
3Device complexity
If the UE uses a single receive beam for SFN transmission, then the receiver complexity is reduced, but the signal quality from neighbor cells may be suboptimal
Solution Approach 1:
The patent inverts the traditional approach by having neighbor cells adapt their transmit beams to match the UE's receive beam characteristics. Instead of the UE switching between multiple receive beams, the neighbor cells use SRS measurements to determine and configure their transmit beams, achieving high signal quality while the UE maintains a single receive beam configuration
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. A serving cell may configure one or more neighbor cells to perform measurements on sounding reference signals (SRSs) received from a user equipment (UE). The serving cell and a subset of the one or more neighbor cells may then transmit data to the UE in a single frequency network (SFN) transmission based on the SRS measurements. For instance, the serving cell may determine whether to add each of the one or more neighbor cells to an SFN cell group for an SFN transmission to a UE based on measurements performed by each neighbor cell on SRSs received from the UE. A neighbor cell of the one or more neighbor cells may also determine which beam to use for an SFN transmission to a UE based on measurements performed by the neighbor cell on SRSs received from the UE.