Cell Selection Using RRM Reference Signals in Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently selecting an optimal cell for user equipment, particularly in environments with full-dimension MIMO or amorphous cells, leading to increased latency and unnecessary handover or cell re-selection procedures.
Innovation Solution
A method for selecting a cell based on a reference signal (RRM-RS) that includes transmitting a random access preamble, receiving a random access response, and sending an uplink message with RRM measurement values, using both Cell-specific Reference Signal (CRS) and RRM-RS measurements to determine the optimal cell for initial access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cell selection is performed using only CRS-based RRM measurement, then compatibility with existing systems is maintained, but measurement precision and cell selection accuracy are insufficient in full-dimension MIMO and amorphous cell environments
Solution Approach 1:
The patent segments the reference signal into two distinct types: CRS (Cell-specific Reference Signal) for legacy compatibility and RRM-RS (Radio Resource Management Reference Signal) for enhanced measurement precision. This segmentation allows the system to maintain backward compatibility while introducing new measurement capabilities for full-dimension MIMO and amorphous cell environments without requiring complete system redesign.
Solution Approach 2:
The patent introduces a new dimension to the reference signal structure by adding RRM-RS as a supplementary measurement resource alongside the traditional CRS. This dimensional expansion enables the system to perform RRM measurements in both legacy and advanced antenna configurations simultaneously, resolving the contradiction between maintaining simplicity and improving measurement accuracy.
2Loss of time
If user equipment performs initial access without RRM-RS based measurements, then the initial access procedure is simple, but latency increases and optimal cell selection is not achieved
Solution Approach 1:
The patent implements preliminary action by having user equipment perform RRM-RS based measurements during the cell search and selection phase before initiating the random access procedure. This advance measurement and cell selection based on RRM-RS enables the UE to identify the optimal cell in advance, reducing access latency while maintaining a straightforward initial access流程.
Solution Approach 2:
The patent substitutes the traditional CRS-only measurement mechanism with an enhanced RRM-RS based measurement system for initial cell selection. This substitution replaces the limited measurement capability with a more sophisticated approach that provides better cell selection accuracy, thereby reducing latency without significantly complicating the initial access procedure.
3Reliability
If additional handover or cell re-selection procedures are implemented to achieve optimal cell selection, then cell selection accuracy improves, but system complexity and processing overhead increase
Solution Approach 1:
The patent performs the cell selection decision in advance during the initial access phase using RRM-RS measurements, rather than relying on subsequent handover or cell re-selection procedures. This preliminary cell selection based on accurate RRM-RS measurements ensures reliable cell selection from the outset, eliminating the need for additional corrective procedures and reducing overall system complexity.
Data Source
AI summary
Disclosed are method and device for selecting a cell in a wireless communication system. In particular, a method for selecting a cell by a terminal in a wireless communication system comprises the steps of: transmitting a random access preamble in a cell, which is selected by a terminal, to a base station; receiving a random access response from the base station; and, as a response to the random access response, transmitting an uplink message to the base station through a physical uplink shared channel (PUSCH), wherein the uplink message can comprises a radio resource management (RRM) measurement value which has been measured on the basis of a reference signal.