Secondary eNodeB Common Search Space Design for Dual Connectivity
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Solution Overview
Problem
In wireless communication systems with dual connectivity, User Equipment (UE) faces increased complexity in monitoring common search spaces (CSS) on both Master eNB and Secondary eNB, leading to a higher number of blind decodings, which complicates processing and power consumption.
Innovation Solution
A CSS design is proposed for the Secondary eNB that supports only the Random Access Channel (RACH) procedure, allowing the UE to monitor either CSS or UE-specific search space (USS) without increasing the maximum number of blind decodings, by limiting the monitored formats and Radio Network Temporary Identifiers (RNTIs), thereby reducing processing and power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE monitors all DCI formats and RNTIs in CSS on both MeNB and SeNB, then the CSS functionality is complete, but the number of blind decodings increases by twelve, increasing UE complexity
Solution Approach 1:
The patent extracts only the essential RNTIs (RA-RNTI and temporary C-RNTI) needed for RACH procedure support from the complete set of CSS-monitored RNTIs. This selective extraction allows the UE to monitor a reduced subset of CSS candidates specifically for random access purposes, eliminating the need to monitor all twelve additional blind decodings while maintaining necessary CSS functionality for dual connectivity
Solution Approach 2:
The patent segments CSS monitoring into distinct functional components: RACH-specific monitoring (using RA-RNTI and temporary C-RNTI) and other CSS functions. By separating these functions and implementing time-sharing between CSS and USS monitoring, the system reduces overall UE complexity while preserving essential connectivity capabilities
2Adaptability or versatility
If the UE monitors CSS on SeNB with all DCI formats, then the CSS supports all functions, but the maximum number of blind decodings increases, increasing power consumption
Solution Approach 1:
The patent extracts only the minimal set of DCI formats and RNTIs necessary for RACH procedure completion from the full CSS monitoring set. This extraction reduces the number of blind decoding operations from twelve additional decodings to a manageable subset, directly reducing power consumption while maintaining essential random access functionality
Solution Approach 2:
The patent implements periodic time-sharing between CSS and USS monitoring, where the UE alternates between monitoring common search space and UE-specific search space based on operational state. This periodic switching reduces continuous monitoring overhead and associated power consumption while ensuring timely detection of RACH-related DCI messages
3Adaptability or versatility
If the UE monitors both CSS and USS simultaneously, then all search spaces are covered, but the processing complexity increases
Solution Approach 1:
The patent implements dynamic monitoring behavior where the UE adaptively switches between CSS and USS monitoring based on operational state (RACH procedure active or inactive). This dynamic approach allows the system to maintain comprehensive search space coverage when needed while reducing processing complexity during normal operation, avoiding the need to monitor both simultaneously in all states
Data Source
AI summary
A method is provided for receiving, at a receiving device, a control information message from a transmitting device. An example method includes determining at a user equipment (UE) a status of the UE and monitoring at the UE based on the status either a common search space (CSS) of a cell or a UE-specific search space (USS) of the cell. The cell is a cell of a secondary eNodeB for communicating with the UE. The method may further include monitoring a CSS and a USS of a cell of a master eNodeB (MeNB) simultaneously while monitoring either the CSS or the USS of the cell of the secondary eNodeB. The status may be a status of the UE with respect to a Random Access Channel (RACH) procedure with the cell.