DCI NDI Bit Segmentation for NB-IoT Transport Block Scheduling
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Solution Overview
Problem
In NB-IoT systems, scheduling two transport blocks (TBs) in one downlink control information (DCI) increases overheads and reduces retransmission efficiency due to the need for accurate indication of new and retransmission data indicators (NDIs) within the limited bit fields, leading to potential misidentification of which TBs require retransmission.
Innovation Solution
The proposed solution involves using two distinct bits within the DCI to independently indicate the NDIs associated with each TB, allowing for clear identification and interpretation of new and retransmission data, thereby reducing overheads and improving retransmission accuracy without altering the DCI structure or length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If two transport blocks are scheduled in one DCI to reduce overheads, then DCI overhead is reduced, but retransmission accuracy deteriorates due to difficulty in accurately indicating NDIs for each TB
Solution Approach 1:
The patent segments the NDI indication for two transport blocks into two separate bits within the DCI structure. Each bit independently indicates the NDI status for its corresponding TB, allowing accurate distinction between new and retransmission data for each TB while maintaining compact DCI formatting.
Solution Approach 2:
The patent changes the parameter representation by using two distinct bits instead of a combined or shared indication mechanism. This parameter change enables independent control and clear identification of NDI status for each TB, resolving the ambiguity that would otherwise occur when scheduling two TBs in one DCI.
2Productivity
If two transport blocks are scheduled in one DCI, then scheduling efficiency is improved, but retransmission efficiency deteriorates due to potential misidentification of TBs requiring retransmission
Solution Approach 1:
The patent applies segmentation by dividing the NDI indication into separate bits for each TB. This allows the system to maintain high scheduling efficiency through consolidated DCI while ensuring high retransmission efficiency through unambiguous, independent NDI status indication for each TB, eliminating misidentification risks.
Solution Approach 2:
The patent implements a feedback mechanism where each TB's NDI status is independently indicated, allowing the receiver to accurately determine which TBs require retransmission. This feedback clarity ensures that retransmission operations are performed correctly without unnecessary retransmissions or missed corrections.
3Measurement precision
If separate bit indication is used for each NDI, then retransmission accuracy is improved, but DCI overhead increases
Solution Approach 1:
The patent uses exactly two bits for NDI indication, which is the minimum necessary to achieve accurate retransmission identification for two TBs. This partial action approach provides sufficient precision for the required function without adding excessive overhead, maintaining an optimal balance between accuracy and efficiency.
Solution Approach 2:
The patent changes the parameter encoding to use two bits total (one per TB) rather than more complex encoding schemes. This parameter change achieves high retransmission accuracy while minimizing overhead, as each bit directly and efficiently indicates the NDI status for its corresponding TB without redundancy or complexity.
Data Source
AI summary
This application discloses a data transmission method which includes: receiving DCI, wherein two TBs or one TB can be scheduled in the DCI, the DCI comprises a third bit, the third bit indicates that a quantity of the TB(s) scheduled in the DCI is 1 or 2, and the DCI further comprises a first bit and/or a second bit; and when the quantity of the TB(s) is 1, performing, based on the third bit, and the first bit or second bit, uplink or downlink data transmission, wherein the first or second bit indicates a NDI associated with the TB scheduled in the DCI; or when the quantity of the TB(s) is 2, performing, based on the third, first bit, and second bit, uplink or downlink data transmission, wherein the first and the second bit respectively indicate two NDIs associated with the two TBs.