Configurable 2-Step Random Access MAC PDU for Latency Reduction
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Solution Overview
Problem
The 2-step random access procedure in wireless communication networks faces challenges in reducing latency and delay, particularly when including RRC signaling, which can hinder improvements in unlicensed frequency deployments.
Innovation Solution
A method that allows for configurable inclusion of MAC SDU for SRB or DRB in the MAC PDU carrying the random access success response message, enabling the network node to adapt based on network deployment, RRC processing delay, and other factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If all RRC signaling information is included in the single network response of the 2-step procedure, then the information completeness is improved, but the latency and delay increase due to additional processing time
Solution Approach 1:
The network response information is segmented into two parts: essential random access response information sent immediately in the network response message, and RRC signaling information sent separately in subsequent downlink transmissions. This segmentation allows the critical latency-sensitive portion to be delivered quickly while the information-complete portion is delivered subsequently, resolving the contradiction between speed and completeness.
2Loss of time
If RRC signaling is transmitted separately from the network response, then the latency for channel clearing is reduced, but the procedure complexity increases
Solution Approach 1:
The system dynamically adapts the random access procedure based on network conditions and requirements. The network can configure whether RRC signaling is included in the network response or sent separately, allowing flexible optimization between latency and complexity depending on the specific deployment scenario and traffic conditions.
3Loss of time
If the 2-step procedure is implemented without RRC signaling in the network response, then the latency improvement is achieved, but the information completeness deteriorates
Solution Approach 1:
The essential random access response information is delivered in the preliminary network response message to achieve immediate latency improvement, while the RRC signaling information is prepared and transmitted in advance through separate downlink transmissions, ensuring that both speed and information completeness requirements are met through staged delivery.
Data Source
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AI summary
A wireless device is configured to receive information from a network node. The information indicates whether or not a medium access control, MAC, service data unit, SDU, for a signaling radio bearer, SRB, or data radio bearer, DRB, is to be received by the wireless device in the same MAC protocol data unit, PDU, as a MAC PDU carrying a random access success response message. This random access success response message indicates both a random access channel and an uplink shared channel payload were decoded successfully. In some embodiments, the wireless device is configured to receive a MAC PDU carrying the random access success response message, and to process the received MAC PDU based on the received information indicating whether a MAC SDU for an SRB or DRB is included in the received MAC PDU.