Msg3 Time-Domain Resource Allocation With Slot Offset Adjustment
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Solution Overview
Problem
In 5G NR, the existing time-domain resource allocation for Msg3 transmissions during the random access procedure does not adequately account for the larger processing time required for decoding the uplink grant received on the PDSCH, leading to potential timing misalignments and inefficiencies in PUSCH transmissions.
Innovation Solution
A method is introduced to reuse the regular PUSCH table for Msg3 time-domain resource allocation by adding an additional slot offset value based on the additional processing time needed for decoding the RAR message, ensuring sufficient processing time and maintaining timing alignment, which is calculated as a function of the subcarrier spacing and processing times from predefined tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the existing PUSCH table is used for Msg3 time-domain resource allocation without modification, then the signaling overhead is reduced and the table structure is simplified, but the processing time for decoding the RAR message is insufficient leading to timing misalignment
Solution Approach 1:
The patent modifies the slot offset parameter K2 in the PUSCH table by adding a predetermined value specifically for Msg3 transmissions. This parameter change ensures that the uplink grant provides sufficient processing time for RAR message decoding while maintaining the same PUSCH table structure for both regular and Msg3 transmissions, thus resolving the contradiction between table simplicity and timing alignment reliability
2Reliability
If a separate PUSCH table is created for Msg3 transmissions to account for additional processing time, then the timing alignment is ensured, but the signaling overhead increases and the system complexity increases
Solution Approach 1:
The patent makes the single PUSCH table universal by enabling it to serve both regular PUSCH transmissions and Msg3 transmissions. Through the application layer filter and the predetermined value addition mechanism, one table structure handles multiple transmission types with different processing time requirements, eliminating the need for separate tables and reducing system complexity while ensuring proper timing alignment
3Reliability
If the slot offset value K2 is increased by adding a predetermined value for Msg3, then the processing time for RAR decoding is sufficient, but the transmission delay increases
Solution Approach 1:
The patent applies partial action by adding a predetermined value to the slot offset K2 only for Msg3 transmissions, not for all PUSCH transmissions. The application layer filter ensures that the predetermined value is added selectively based on the transmission type, providing the necessary processing time extension only where needed (for RAR decoding) while avoiding unnecessary delays in regular transmissions
Data Source
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AI summary
In a communications system, a User Equipment (UE) initiates a transmission of user data to a host computer by receiving a Random Access Response (RAR) message comprising an indication of a time-domain resource allocation for a Msg3 transmission on PUSCH, and determining a slot offset value, K2, for the Msg3 transmission based on the indication of the time-domain resource allocation and a PUSCH table. The UE adds an additional slot offset value for the Msg3 transmission to the slot offset value, K2, to provide an increased slot offset value for the Msg3, and transmits the Msg3 transmission in accordance with the increased slot offset value, wherein the additional slot offset value varies in relation to an additional processing time Tadd needed for RAR message decoding compared to PDCCH decoding. The UE then transmits, to the base station, the user data to be forwarded to the host computer.