DCI Format N0 Redesign for Flexible NB-IoT EDT Scheduling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current designs for Early Data Transmission (EDT) in NB-IoT and efeMTC lack support for all scheduling options in the MCS index, and the DCI format N0 schedules fixed resources, making it challenging to handle uncertain TBS and repetitions during re-transmissions.
Innovation Solution
The method involves redesigning the DCI format N0 to support EDT by configuring the repetition number, resource allocation, and modulation and coding scheme fields, allowing flexible resource allocation based on the narrowband random access response grant, and using pre-configured values or existing fields to determine the number of repetitions and RUs, ensuring compatibility with various coverage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If DCI format N0 schedules fixed resources, then resource allocation is simple, but it cannot handle uncertain TBS and repetitions during re-transmissions
Solution Approach 1:
The DCI format N0 is enhanced to include dynamic fields for TBS indication and repetition number indication, allowing the scheduling parameters to change based on re-transmission needs rather than being fixed. This enables the system to adapt resource allocation dynamically for EDT re-transmissions while maintaining backward compatibility with existing DCI structures
Solution Approach 2:
The patent introduces new parameters (TBS indication field, repetition number indication field) to the DCI format N0, changing the parameter set from fixed resource allocation to flexible parameter-based allocation. This allows the base station to indicate different TBS values and repetition numbers for re-transmissions based on channel conditions and data requirements
2Adaptability or versatility
If all scheduling options in MCS index are supported, then EDT flexibility is improved, but device complexity increases
Solution Approach 1:
The base station performs preliminary configuration by indicating the TBS and repetition number in the DCI format N0 before the actual re-transmission occurs. This allows the UE to pre-prepare for the re-transmission with known parameters, reducing the need for complex real-time calculations and decision-making at the UE side
Solution Approach 2:
The DCI format N0 acts as an intermediary that carries scheduling information from the base station to the UE. By embedding TBS indication and repetition number indication in this intermediary message, the system provides flexible scheduling without requiring complex UE-side algorithms to determine these parameters
3Adaptability or versatility
If DCI format N0 includes TBS and repetition number fields, then re-transmission scheduling is flexible, but signaling overhead increases
Solution Approach 1:
The DCI format N0 is designed to serve multiple functions: it maintains its original role in scheduling NPUSCH while also carrying TBS indication and repetition number indication for EDT re-transmissions. This multi-functionality allows flexible re-transmission scheduling without requiring separate dedicated signaling messages, thereby limiting the increase in signaling overhead
4Productivity
If EDT is supported during random access, then data transmission efficiency is improved, but contention resolution complexity increases
Solution Approach 1:
The random access procedure is segmented into distinct phases: initial access using conventional NPRACH/RAR, and data transmission phase using EDT with DCI format N0. By separating these functions and using different message formats for each phase, the system achieves efficient data transmission without complicating the fundamental random access contention resolution mechanism
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present disclosure provides a method executed by user equipment, including: step (S1): transmitting, by user equipment, a Narrowband Physical Random Access Channel (NPRACH) preamble to a base station, where an NPRACH resource used by the user equipment indicates that the user equipment requests use of EDT; step (S2): receiving, by the user equipment, a narrowband random access response grant from the base station, where the value of a Modulation and Coding Scheme (MCS) index field indicates that resources are allocated to a Msg3 via EDT; step (S3): transmitting, by the user equipment, the Msg3 according to an indication of the narrowband random access response grant; step (S4): receiving, by the user equipment, a Downlink Control Information (DCI) format NO from the base station; and step (S5): re-transmitting, by the user equipment, the Msg3 according to an indication of the DCI format N0. In step (S2), a modulation scheme for the Msg3 is determined by a subcarrier indication field in the narrowband random access response grant. The present disclosure also provides corresponding user equipment and a corresponding base station.