Random Access Preamble Signaling for On-Demand System Information
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Solution Overview
Problem
Existing wireless communication systems, particularly in 5G New Radio systems, lack efficient methods for random access procedures, especially for cases other than data transfer initiation, such as on-demand system information requests, leading to unnecessary signaling and inefficiencies.
Innovation Solution
A user equipment and base station apparatus are designed to utilize distinct preamble indices for designated requests, allowing for efficient random access procedures by associating specific preamble indices with particular requests, such as on-demand system information delivery, and confirming successful receipt through dedicated indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE sends a RA preamble for on-demand system information request, then the system information can be requested, but unnecessary signaling and resource allocation occur
Solution Approach 1:
The patent changes the parameter of preamble index assignment by introducing dedicated preamble indices specifically for on-demand system information requests, distinguishing them from preambles used for data transfer initiation. This parameter differentiation allows the network to identify and handle SI requests efficiently without processing them through the full data transfer protocol, thereby reducing unnecessary signaling overhead and energy consumption.
2Reliability
If the network responds to all RA preambles with MAC RAR, then all requests are acknowledged, but resource allocation is inefficient
Solution Approach 1:
The patent applies local quality by differentiating the response mechanism based on the type of preamble received. When a dedicated preamble index for on-demand system information is detected, the network provides a simplified acknowledgment without allocating full MAC RAR resources. This localized adaptation of response quality ensures reliable acknowledgment of SI requests while optimizing resource utilization by avoiding unnecessary resource allocation for requests that do not require data transfer setup.
3Reliability
If the UE continues with full RACH procedure for SI request, then synchronization is maintained, but signaling overhead increases
Solution Approach 1:
The patent extracts the essential function of uplink synchronization from the full RACH procedure and applies it specifically to on-demand system information requests. By using dedicated preamble indices, the UE can obtain synchronization information through a simplified acknowledgment response rather than completing the entire four-message RACH exchange. This extraction of the critical synchronization function reduces signaling overhead and access delay while maintaining the necessary uplink synchronization for SI reception.
Data Source
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AI summary
In one of its aspects the technology disclosed herein concerns a communications system comprising an access node (22) and a wireless terminal (26). The wireless terminal comprises receiving circuitry (40) and transmitting circuitry (44) as well as processor circuitry (40). The transmitting circuitry configured to transmit a random access preamble configured for a request of system information. The receiving circuitry configured to receive a random access response. The processor circuitry is configured to consider a reception of the random access response as successful in a case that the random access response comprises a random access preamble identifier (RAPID) corresponding to the transmitted random access preamble, wherein the RAPID is in a medium access control (MAC) subheader. The processor circuitry is configured to consider a random access procedure as successfully completed in a case that a MAC random access response (MAC RAR) corresponding to the MAC subheader is not included in a MAC protocol data unit (MAC PDU).