Dual-Polarized Antenna Beam Alignment Using SSB Polarization Mapping
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Solution Overview
Problem
In 5G NR systems using dual-polarized antennas, UEs face challenges in distinguishing signals transmitted from dual-polarized antennas at the base station due to lack of knowledge about the polarization direction, leading to increased resource overhead and latency during beam sweeping for initial access.
Innovation Solution
Transmitting synchronization signals (SSB) on two antenna ports with specific patterns that associate each port with distinct polarization directions, enabling simultaneous measurement and reduced latency by allowing the UE to identify the polarization direction of received signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the base station transmits the same SSB signal via dual-polarized antennas without polarization indication, then the transmission simplicity is maintained, but the UE cannot identify which polarized antenna the received signal is from, leading to increased measurement complexity and latency
Solution Approach 1:
The patent applies the principle of distinguishing signals through different polarization states (analogous to color changes), where the base station transmits the same SSB signal on two antenna ports with different polarization directions. The UE can then identify the polarization direction of received signals by measuring the signal strength on each antenna port and comparing them, thereby reducing beam alignment latency without complicating the transmission process.
2Area of stationary object
If the base station uses dual-polarized antennas to transmit SSB signals, then the signal coverage is improved, but the resource overhead increases due to the need for beam sweeping without polarization information
Solution Approach 1:
The patent segments the SSB transmission by allocating different polarization directions to different antenna ports. This segmentation allows the UE to perform targeted measurements on each port, reducing the need for exhaustive beam sweeping across all possible directions and polarizations, thereby reducing resource overhead while maintaining the coverage benefits of dual-polarized antennas.
3Measurement precision
If the UE performs beam sweeping to align with base station beams without polarization knowledge, then the beam alignment accuracy can be achieved, but the measurement complexity and time consumption increase significantly
Solution Approach 1:
The patent introduces polarization direction as an intermediary parameter that facilitates beam alignment. By transmitting SSB signals on two antenna ports with distinct polarization directions, the polarization state serves as a mediator that helps the UE identify the correct beam direction more efficiently, reducing measurement complexity while maintaining alignment accuracy.
Data Source
AI summary
In some embodiments, dual-polarized antennas may be implemented by establishing a mapping relation between synchronization signals and polarization directions of polarized antennas at the base station or polarization directions in relation to a reference plane. Examples of synchronization signals include primary synchronization signal (PSS), secondary synchronization signal (SSS), physical broadcast channel (PBCH), and demodulation reference signal (DMRS) for PBCH.