Beamformed Synchronization Signal Rotation in Massive MIMO
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Solution Overview
Problem
Current massive MIMO communications systems face challenges in efficiently transmitting beamformed broadcast and synchronization signals, leading to high overhead and interference issues, particularly in mmWave communications where signals can be easily blocked by objects.
Innovation Solution
A method and system for transmitting beamformed signals using a transmit-receive point (TRP) that beamforms synchronization signals on multiple spatially separated transmission beams with unique identifiers, rotated over time, and combines these with broadcast signals to reduce overhead and interference, allowing for simultaneous transmission on multiple beams with transmit diversity and different subbands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamformed broadcast and synchronization signals are transmitted using multiple transmission beams, then coverage and synchronization performance are improved, but communication overhead increases
Solution Approach 1:
The patent segments the transmission process into two distinct phases: a synchronization phase where multiple beamformed synchronization signals are transmitted for cell search and timing acquisition, and a broadcast phase where beamformed broadcast signals are transmitted for system information delivery. This segmentation allows the system to achieve reliable synchronization through multiple beams while controlling overhead by separating synchronization functions from broadcast functions.
Solution Approach 2:
The patent implements periodic transmission patterns where synchronization signals are transmitted in periodic synchronization occasions, and broadcast signals are transmitted in periodic broadcast occasions. This periodic action allows the system to achieve coverage enhancement through repeated transmissions while managing overhead by controlling the frequency and duration of each transmission type.
2Area of stationary object
If beamformed signals are transmitted on multiple spatially separated beams, then coverage is enhanced, but interference between beams increases
Solution Approach 1:
The patent segments the time-frequency resources into distinct synchronization occasions and broadcast occasions, with each occasion dedicated to specific transmission types. By assigning different time-frequency resources to different beam groups and signal types, the system achieves wide coverage through multiple spatially separated beams while minimizing interference between concurrent beam transmissions.
Solution Approach 2:
The patent extends the resource allocation from purely spatial domain to include time and frequency dimensions. By distributing beams across multiple time-frequency resources rather than simultaneously in the same resources, the system achieves enhanced coverage through spatial multiplicity while reducing interference through temporal and spectral separation.
3Measurement precision
If synchronization signals are transmitted with unique identifiers on rotated beams, then beam identification accuracy is improved, but transmission complexity increases
Solution Approach 1:
The patent segments the beam identification process into two stages: first, users identify the synchronization signal beam through correlation detection of unique identifiers (such as PSS/SSS sequences) transmitted on rotated beams; second, users identify the broadcast beam through detection of broadcast signal characteristics. This segmentation simplifies the overall complexity by breaking down the identification process into manageable detection stages.
Solution Approach 2:
The patent transmits synchronization signals with unique identifiers on rotated beams before transmitting broadcast signals. This preliminary action allows users to first acquire beam direction and timing information through synchronization signal detection, which then facilitates the subsequent detection of broadcast signals on the identified beam, reducing the overall complexity of beam identification.
4Reliability
If beamformed broadcast signals are transmitted on all available beams, then reliability is improved, but resource consumption increases
Solution Approach 1:
The patent segments broadcast signal transmission into multiple broadcast occasions, each dedicated to specific beam groups. Instead of transmitting on all available beams simultaneously, the system transmits beamformed broadcast signals on selected beams during different broadcast occasions, achieving reliable delivery through repeated transmissions while reducing instantaneous energy consumption and overall resource usage.
Solution Approach 2:
The patent implements periodic broadcast transmissions where beamformed broadcast signals are transmitted in periodic broadcast occasions rather than continuously on all beams. This periodic action ensures reliable delivery through repetition while significantly reducing energy consumption by controlling the frequency and duration of transmissions.
Data Source
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AI summary
A method for transmitting beamformed signals includes beamforming a synchronization signal in accordance with a first set of spatially separated transmission beams, thereby producing first beamformed synchronization signals, transmitting the first beamformed synchronization signals, determining if a first synchronization cycle is complete, and when the first synchronization cycle is not complete, rotating the first set of spatially separated transmission beams, and repeating the beamforming, the transmitting, and the determining until the first synchronization cycle is complete.