PDCCH Ordered 2-Step RACH MsgA PUSCH Triggering
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Solution Overview
Problem
The existing 2-step random access (RACH) procedures in 5G wireless communication systems face challenges in efficiently triggering the transmission of MsgA PUSCH during PDCCH ordered 2-step RACH procedures, particularly in positioning operations, due to the lack of defined mechanisms for triggering associated MsgA PUSCH transmission.
Innovation Solution
The proposed solution involves re-interpreting reserved bits in DCI format 1_0 to trigger MsgA PUSCH transmission, using MsgA PUSCH resource index, and configuring separate MsgA PUSCH resources for PDCCH ordered 2-step RACH, allowing for explicit indication of MsgA PUSCH resources and parameters such as time-frequency domain allocation, modulation, and power control, to facilitate timely uplink synchronization and positioning measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PDCCH ordered 2-step RACH procedure is implemented without defined triggering mechanism, then positioning operations can be performed, but MsgA PUSCH transmission cannot be efficiently triggered
Solution Approach 1:
The patent re-interprets reserved bits in DCI format 1_0 to carry MsgA PUSCH resource index information. By changing the usage of existing signaling parameters (reserved bits) to convey new information (MsgA triggering and resource indication), the system enables MsgA PUSCH transmission triggering without adding new signaling structures, thus resolving the contradiction between positioning capability and triggering mechanism.
2Measurement precision
If separate MsgA PUSCH resources are configured for PDCCH ordered 2-step RACH, then uplink synchronization accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent configures separate MsgA PUSCH resources that can serve multiple purposes: positioning operations, uplink synchronization, and general random access. By making the resource configuration universal rather than dedicated to a single function, the system improves synchronization accuracy while avoiding redundant signaling for each specific use case.
Solution Approach 2:
The patent uses DCI format 1_0 with re-interpreted reserved bits to indicate MsgA PUSCH resource index. This parameter change approach allows the system to point to pre-configured resources without transmitting full resource allocation details, thereby improving synchronization precision while minimizing additional signaling overhead.
3Loss of time
If MsgA PUSCH resource index is used to trigger transmission, then access latency is reduced, but device complexity increases
Solution Approach 1:
The patent pre-configures MsgA PUSCH resources and their indices before actual transmission is needed. When positioning or random access is required, the UE simply needs to decode the resource index from DCI format 1_0 and use the pre-configured resources. This preliminary configuration approach reduces access latency while keeping the triggering mechanism simple.
Solution Approach 2:
The patent uses the existing DCI format 1_0 structure and re-uses reserved bits rather than creating a completely new signaling format. By copying and adapting existing signaling structures rather than inventing new ones, the system reduces access latency through efficient triggering while minimizing the increase in device complexity.
Data Source
AI summary
An approach is described for a base station (gNB) that includes the following features. The features include transmitting, by the gNB, a PDCCH signal to a user equipment (UE), wherein the PDCCH signal includes an indication of a PDCCH ordered 2-step RACH procedure. The features also include receiving, by the gNB, a first step of the 2-step RACH procedure, wherein the first step includes a PRACH preamble and an associated MsgA physical uplink shared channel (PUSCH) from the UE.