On-Demand System Information Request via Random Access Channel
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Solution Overview
Problem
Existing cellular technologies, particularly in 5G NR, face challenges in efficiently managing on-demand System Information (SI) requests without state transitions in User Equipment (UE).
Innovation Solution
The proposed solution utilizes the random access channel for on-demand SI requests, allowing UEs in idle, inactive, or connected states to initiate a random access procedure without state transitions. This involves using a random access preamble configured for SI requests and corresponding Physical Random Access Channel (PRACH) time-frequency resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a UE sends an on-demand SI request using existing random access procedures, then the SI request can be transmitted, but the random access response includes unnecessary information (TA command, uplink grant, temporary C-RNTI) that increases message size and processing overhead
Solution Approach 1:
The patent extracts and removes unnecessary information elements (TA command, uplink grant, temporary C-RNTI) from the random access response message when the UE is in idle or inactive state, keeping only the essential RAPID and on-demand SI request acknowledgment, thereby reducing message size and processing overhead
Solution Approach 2:
The patent applies different random access response configurations based on the UE's state: a simplified response without TA command/uplink grant for idle/inactive states, and a complete response with all elements for connected states, optimizing each case locally
2Reliability
If the random access response includes TA command and uplink grant for all UEs, then connected state UEs can maintain synchronization, but idle and inactive state UEs receive unnecessary information that increases signaling overhead
Solution Approach 1:
The patent applies different random access response configurations based on the UE's state: a simplified response without TA command/uplink grant for idle/inactive states, and a complete response with all elements for connected states, optimizing each case locally
Solution Approach 2:
The patent changes the parameters of the random access response message based on UE state, specifically conditionally including or excluding TA command and uplink grant elements to match the synchronization needs of different UE states
Data Source
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AI summary
A User Equipment (UE) including a wireless transceiver and a controller is provided. The wireless transceiver performs wireless transmission and reception to and from a service network. The controller initiates a random access procedure with the service network by controlling the wireless transceiver to perform wireless transmission using at least one of: a random access preamble configured for System Information (SI) request, and a corresponding Physical Random Access Channel (PRACH) time-frequency resource allocated for the random access preamble. Also, the controller receives a random access response, which includes a Random Access Preamble Identifier (RAPID) only and does not include a Timing Advance (TA) command, an uplink grant, and a temporary Cell Radio Network Temporary Identifier (C-RNTI), from the service network via the wireless transceiver.