Random Access Configuration for CRS-Free Downlink Reception
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In Long Term Evolution (LTE) systems, the random access procedure relies on Cell Reference Signals (CRS) for uplink synchronization, but next-generation networks aim to minimize static signals to reduce energy consumption and interference, potentially eliminating CRS, making it difficult for terminal devices to receive downlink messages during random access.
Innovation Solution
The method involves transmitting access configuration information, including Resource Elements (REs), Demodulation Reference Signal (DMRS), payload size, Modulation and Coding Scheme (MCS), and receiving timing, to enable terminal devices to receive random access messages without relying on CRS, using either a single configuration or a set of candidate configurations and mapping rules, and updating this information through Dedicated and Common Access Information Tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CRS is used for random access procedure, then terminal device can receive downlink messages reliably, but energy consumption increases and interference to neighboring UEs increases
Solution Approach 1:
The patent extracts the CRS dependency from the random access procedure by introducing DMRS-based reception. The terminal device receives downlink messages (MSG2/MSG4) using DMRS instead of CRS, thereby removing the requirement for CRS to be always on. This allows the network to turn off CRS when not needed, reducing energy consumption while maintaining reliable message reception through alternative reference signals.
2Use of energy by moving object
If CRS is eliminated to reduce energy consumption, then energy efficiency improves, but terminal device cannot receive downlink messages during random access
Solution Approach 1:
The patent introduces DMRS as an intermediary reference signal that enables downlink message reception without requiring CRS. The DMRS serves as a mediator between the network node and terminal device, providing the necessary reference for message decoding when CRS is unavailable. This intermediary allows the system to maintain communication reliability while eliminating the need for persistent CRS transmission.
3Object-affected harmful factors
If CRS is minimized or eliminated, then interference to neighboring UEs reduces, but random access procedure becomes unavailable
Solution Approach 1:
The patent changes the fundamental parameter of reference signal usage from CRS-based to DMRS-based. This parameter change enables the random access procedure to function without CRS, thereby eliminating interference to neighboring UEs while maintaining full random access capability. The system adapts to the new parameter regime by using different reference signals for message reception.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present disclosure provides a method (200) in a network node. The method (200) comprises: transmitting (S210) to a terminal device access configuration information required for the terminal device to receive a first random access message from the network node; and transmitting (S220) the first random access message to the terminal device based on the access configuration information.