CoMP Cell Selection via PRACH Measurements
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Solution Overview
Problem
In CoMP communication systems, achieving fast cell selection is challenging during radio link establishment and short data transmission, as existing methods require complex and time-consuming processes to determine secondary serving cells, limiting the CoMP gain for UEs at cell edges.
Innovation Solution
A method for fast CoMP cell selection involves the primary serving cell receiving PRACH measurements from candidate cells, selecting secondary serving cells based on signal strength, and using PRACH information to reduce computation complexity and hardware costs, enabling quick activation of CoMP cells during radio link establishment and short data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex cell selection processes are used to determine secondary serving cells in CoMP systems, then cell selection accuracy is improved, but cell selection time increases
Solution Approach 1:
The patent applies preliminary action by having candidate cells pre-measure and report PRACH preamble signals before the actual cell selection decision is needed. The primary serving cell receives these pre-collected measurements and uses them to quickly determine secondary serving cells, avoiding the need for time-consuming measurements at the decision moment.
Solution Approach 2:
The patent extracts only the essential PRACH preamble signal measurements from the complex cell selection process. By focusing solely on these key measurements rather than comprehensive cell evaluation metrics, the system achieves fast cell selection with sufficient accuracy for CoMP operation.
2Measurement precision
If comprehensive PRACH measurements are collected from all candidate cells, then cell selection accuracy is improved, but computation complexity increases
Solution Approach 1:
The patent extracts only the necessary PRACH preamble signal strength measurements from candidate cells, ignoring other comprehensive cell parameters. This selective extraction maintains sufficient selection accuracy while dramatically reducing the computational burden of evaluating multiple cell parameters.
Solution Approach 2:
The patent uses simple, lightweight PRACH preamble measurements as a disposable indicator for cell selection decisions. These minimal measurements serve the purpose of identifying suitable secondary serving cells without requiring complex, resource-intensive evaluation metrics.
3Speed
If fast cell selection is implemented for short data transmission, then system responsiveness is improved, but measurement reliability may deteriorate
Solution Approach 1:
The patent performs PRACH measurements in advance during the random access procedure, which naturally occurs before data transmission begins. This preliminary measurement timing ensures that reliable measurements are obtained without adding delay to the actual data transmission, as the measurements are collected as part of the initial access sequence.
Data Source
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AI summary
The present disclosure relates to a cell selection scheme. In one embodiment, there provides a method for performing a cell selection for a UE at a primary serving cell of the UE in a CoMP cluster including the primary serving cell and one or more candidate cells, the method comprising the steps of: receiving PRACH measurements for the UE from the candidate cells; and selecting from the candidate cells one or more cells for the UE as its secondary serving cells based on the received PRACH measurements.