Network Access via SS-Based Cell Selection and CRS Reduction
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Solution Overview
Problem
The persistent interference and lack of flexibility in LTE due to the always-on nature of the common reference signal (CRS) and reliance on physical cell identifiers (PCID) lead to forward compatibility issues.
Innovation Solution
A method and system that utilize synchronization sequences (SS) and radio resource management (RRM) measurements for cell selection and mobility support, reducing the need for CRS and PCID, and employing virtual cell identifiers (VCID) and user equipment identifiers (UEID) for flexible network access and connection management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common reference signal (CRS) is transmitted always on in LTE, then downlink channel estimation for demodulation and downlink channel quality measurements are improved, but persistent interference is generated for neighboring cells
Solution Approach 1:
The patent applies periodic action by transitioning from always-on CRS transmission to periodic CSI-RS transmission. The CSI-RS is transmitted only when needed for channel estimation and quality measurements, rather than continuously. This periodic transmission pattern reduces persistent interference to neighboring cells while maintaining the necessary channel estimation functionality when required.
Solution Approach 2:
The patent applies local quality by making reference signal transmission UE-specific and conditional rather than cell-wide and continuous. The CSI-RS is configured individually for specific UEs based on their channel conditions and requirements, allowing channel estimation only where and when needed, thereby reducing unnecessary interference in other areas.
2Reliability
If common reference signal (CRS) is transmitted always on in LTE, then downlink channel quality measurements are improved, but lack of flexibility is caused
Solution Approach 1:
The patent applies dynamics by making the reference signal transmission flexible and adaptive. The CSI-RS transmission is dynamically configured based on UE-specific requirements, channel conditions, and network state. This allows the system to adapt reference signal transmission to actual needs rather than following a static always-on pattern, improving both flexibility and measurement reliability.
Solution Approach 2:
The patent applies universality by using a single CSI-RS structure that can serve multiple functions: channel estimation, quality measurements, and mobility measurements. This multi-functional reference signal replaces the dedicated CRS functionality, providing the same measurement capabilities with greater flexibility and reduced interference.
3Reliability
If physical cell identifier (PCID) is used in CRS and other signals and channels in LTE, then cell identification and synchronization are improved, but forward compatibility issues arise due to rigidity
Solution Approach 1:
The patent applies segmentation by separating cell identification functionality from the CRS structure. The SSB (Synchronization Signal Block) carries cell identification and synchronization information independently, while CSI-RS handles channel estimation and quality measurements. This segmentation allows different signal components to be optimized independently, improving forward compatibility while maintaining reliable cell identification.
Solution Approach 2:
The patent introduces SSB as an intermediary structure that handles cell identification and synchronization functions. This intermediary separates the identification function from the data transmission CRS, allowing the system to evolve the data transmission mechanism (to flexible CSI-RS) without compromising cell identification reliability. The SSB acts as a stable mediator that maintains backward compatibility while enabling forward evolution.
Data Source
AI summary
A method includes a user equipment (UE) receiving, from a first transmission reception point (TRP) on a first carrier, a synchronization signal (SS) and at least a physical broadcast channel (PBCH). The UE performs a random access channel (RACH) procedure with a second TRP on a second carrier in accordance with configuration information from at least the PBCH. The UE on the second carrier establishes a radio resource control (RRC) connection with the second TRP.