Early Data Transmission in Wireless Random Access
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Solution Overview
Problem
Current wireless communication systems experience latency due to the absence of data transmission until the radio resource control (RRC) connection setup is completed, which can be mitigated by enabling early data transmission (EDT) during the random access procedure, but existing methods lack efficient mechanisms for indicating support and managing EDT resources effectively.
Innovation Solution
The proposed solution involves an apparatus for user equipment (UE) that encodes and transmits a physical random access channel (PRACH) sequence with an indication of EDT support, receives and decodes a random access response (RAR) to determine uplink (UL) grants for EDT, and manages resource allocation units and repetitions based on UL grants and higher-layer signaling to facilitate EDT during the random access procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If early data transmission is enabled during random access procedure, then latency is reduced, but device complexity increases due to additional signaling and resource management requirements
Solution Approach 1:
The patent combines data transmission with the random access procedure by allowing Msg3 to carry both RRC connection request and data payload. This merging eliminates the need for separate data transmission resources, reducing latency while distributing complexity across existing protocol layers rather than adding entirely new mechanisms.
Solution Approach 2:
The PRACH resources and Msg3 structure are designed to serve multiple functions: establishing RRC connection, indicating EDT support, and transmitting data payload. This multi-functionality reduces the need for dedicated EDT-specific resources, thereby reducing overall system complexity while enabling low-latency data transmission.
2Loss of information
If EDT support indication is added to PRACH sequence, then EDT capability is communicated, but signal complexity increases
Solution Approach 1:
The EDT support indication is merged into the existing PRACH sequence structure rather than being transmitted as a separate signal. The indication is embedded within the Msg3 payload that is already part of the random access procedure, thereby communicating capability information without adding separate signaling overhead.
Solution Approach 2:
The patent uses existing message structures (Msg3, RAR, UL grant) from the random access procedure to carry EDT-related information. By reusing and adapting existing protocols rather than creating new signaling mechanisms, the solution communicates necessary information while minimizing additional complexity.
3Productivity
If UL grant is used for scheduling EDT, then resource allocation is efficient, but processing complexity increases at the access node
Solution Approach 1:
The UL grant structure is designed to serve dual purposes: scheduling Msg3 transmission and indicating EDT capability. The same grant message that allocates uplink resources also conveys information about whether EDT is supported, eliminating the need for separate resource allocation and capability indication procedures.
Solution Approach 2:
The random access response and UL grant messages contain embedded indicators that allow the UE to self-determine whether EDT is supported and to autonomously proceed with EDT or fallback to conventional procedures. This self-service mechanism reduces the processing burden on the access node by enabling UE-side decision-making.
Data Source
AI summary
Provided herein is design of early data transmission in wireless communication system. An apparatus for a user equipment (UE) includes a processor configured to: encode a physical random access channel (PRACH) sequence from a plurality of PRACH sequence for transmission via a PRACH to perform a random access procedure, wherein indication of support of early data transmission (EDT) that is transmitted during the random access procedure is based on at least one of the plurality of PRACH sequences, higher layer signaling, PRACH resources, PRACH formats, and a payload from the UE; and send the PRACH sequence to a radio frequency (RF) interface; and the RF interface to receive the PRACH sequence from the processor. Design of random access response (RAR) is also disclosed herein.