Multi-bit NDI for 5G HARQ Packet Attribution
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in accurately distinguishing between initial and retransmitted packets due to the limitations of single-bit New Data Indicators (NDIs), leading to ambiguity and potential misattribution of packets during Hybrid Automatic Repeat Request (HARQ) processes.
Innovation Solution
Implementing a multiple bit NDI that rotates through more than two states to indicate new packets, incorporating both a packet identifier and a HARQ transmission index, allowing for clearer differentiation between initial and retransmitted data transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a single-bit NDI is used to indicate new packets, then the signaling overhead is minimized, but the ability to distinguish between initial and retransmitted packets becomes ambiguous
Solution Approach 1:
The NDI is segmented into multiple bits, where each bit provides specific information: one bit indicates whether it's a new packet or retransmission, while additional bits provide packet identification and HARQ transmission indexing. This segmentation resolves the ambiguity of single-bit NDI by distributing information across multiple bits with distinct functions.
Solution Approach 2:
The solution transitions from a single-dimensional (1-bit) NDI to a multi-dimensional NDI structure. The additional bits add new dimensions of information: packet identity differentiation and HARQ transmission attempt indexing. This dimensional expansion enables precise packet attribution without the limitations of binary toggling.
2Reliability
If a multiple bit NDI is implemented to reduce packet attribution ambiguity, then the reliability of HARQ processes improves, but the signaling overhead increases
Solution Approach 1:
The NDI parameter structure is changed from a single bit to multiple bits with specific functional assignments. The additional bits are not arbitrary but serve specific purposes: packet identification and HARQ transmission indexing. This parameter change enables reliable packet attribution while keeping the overhead manageable through structured information encoding.
3Measurement precision
If additional bits are added to the NDI to indicate packet identity and HARQ transmission index, then the precision of packet differentiation improves, but the complexity of the communication protocol increases
Solution Approach 1:
The enhanced NDI is segmented into functional components: bits indicating new packet status, bits for packet identification, and bits for HARQ transmission indexing. This segmentation allows the receiver to process different aspects of packet information independently, reducing overall protocol processing complexity despite the increased bit length.
Solution Approach 2:
The multi-bit NDI structure serves multiple functions simultaneously: it indicates whether a packet is new or retransmitted, identifies the packet sequence, and tracks HARQ transmission attempts. This multi-functionality consolidates what would otherwise require separate signaling mechanisms into a single unified indicator, managing protocol complexity.
Data Source
AI summary
Apparatus, methods, and computer-readable media for facilitating a multiple bit new data indicator are disclosed herein. An example method for wireless communication at a first device includes transmitting a first state of a multiple bit new data indicator (NDI) for a first packet. The example multiple bit NDI indicates more than two different states for indicating a new packet. The example method also includes transmitting the first packet. Additionally, the example method includes transmitting a second state of the multiple bit NDI for a second packet, and the second state being different than the first state. Further, the example method includes transmitting the second packet.