SSB Polarization Variation for RSRP Accuracy
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Solution Overview
Problem
Terminal devices face challenges in obtaining accurate reference signal received power (RSRP) measurements for synchronization signals due to polarization mismatch and frequency selective behavior in the radio propagation channel, leading to erroneous cell selection and unnecessary handovers.
Innovation Solution
Transmitting polarized bursts of Synchronization Signal Blocks (SSBs) in beams, where the polarization changes between consecutive bursts, allowing terminal devices to average RSRP measurements over multiple polarizations and reduce the risk of polarization mismatch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If terminal devices measure RSRP on SSS with fixed polarization, then measurement process is simple, but polarization mismatch occurs leading to inaccurate RSRP values
Solution Approach 1:
The network node transmits SSB bursts with alternating polarizations periodically. Terminal devices perform RSRP measurements across multiple bursts with different polarizations and average the results. This periodic variation in transmission polarization allows terminal devices to obtain accurate RSRP values by averaging measurements taken under different polarization conditions, thereby eliminating polarization mismatch errors while maintaining measurement process simplicity.
2Reliability
If network node transmits SSB with single polarization, then transmission is simple, but terminal devices experience polarization mismatch and erroneous cell selection
Solution Approach 1:
The network node transmits SSB bursts with alternating polarizations in a periodic manner. By switching the polarization of transmitted SSB bursts between different orientations (e.g., vertical and horizontal), the network ensures that terminal devices can reliably perform cell selection and mobility measurements regardless of their receiving polarization state, thereby improving cell selection accuracy without requiring complex multi-antenna systems at the terminal.
Solution Approach 2:
The network node changes the polarization parameter of transmitted SSB bursts between consecutive transmissions. This parameter variation ensures that at least one transmitted burst will be properly received by terminal devices with different polarization orientations, eliminating polarization mismatch issues and ensuring reliable cell selection and mobility measurements.
3Measurement precision
If terminal device uses single polarization for receiving, then receiving process is simple, but frequency selective behavior causes measurement errors
Solution Approach 1:
Terminal devices receive SSB bursts transmitted with alternating polarizations periodically. By averaging RSRP measurements across multiple bursts with different polarizations, terminal devices eliminate the impact of frequency selective fading that affects single-polarization receptions. This approach maintains receiving operation simplicity while significantly improving measurement accuracy through the periodic variation in transmitted polarization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient cell selection by reducing the risk of erroneous cell selection and unwanted handovers, while maintaining low implementation complexity and processing needs.
Implementation Method 1
Polarization of at least one of the SSBs changes between two consecutive bursts of the SSBs
Data Source
AI summary
There is provided mechanisms for transmission of synchronization signals. A method is performed by a network node. The method comprises transmitting polarized bursts of SSB in beams. One SSB is transmitted per each beam in each burst. Polarization of at least one of the SSBs changes between two consecutive bursts of the SSBs.