NTN HARQ Feedback Resource Reuse for IoT Scheduling
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Solution Overview
Problem
In non-terrestrial network (NTN) systems, the long communication delays and large propagation distances lead to inefficiencies in uplink scheduling and resource allocation for user equipment (UE), particularly for IoT services, due to the need for HARQ feedback disabling, which complicates the transmission of scheduling information and increases latency and power consumption.
Innovation Solution
The proposed solution involves reusing HARQ ACK/NACK signals to transmit scheduling information, such as scheduling requests (SR) and buffer status reports (BSR), by allocating NPUSCH resources for HARQ ACK/NACK, allowing the UE to send approximate buffer size information using two-bit encoding, thereby reducing latency and power consumption, and limiting the use of PRACH resources when HARQ feedback is disabled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HARQ feedback is disabled to reduce latency and avoid throughput reduction, then the throughput and latency are improved, but the scheduling information transmission becomes complicated and resource allocation efficiency deteriorates
Solution Approach 1:
The patent applies multi-functionality by enabling the HARQ feedback resources to serve dual purposes: traditional HARQ feedback when enabled, and scheduling information transmission when disabled. The UE can transmit scheduling information (SR/BSR) using the same physical resources allocated for HARQ feedback, thereby eliminating resource waste and simplifying the overall transmission protocol in NTN environments.
2Loss of time
If HARQ feedback is disabled to reduce latency, then the transmission latency is improved, but the scheduling request and buffer status report transmission efficiency deteriorates
Solution Approach 1:
The patent implements preliminary action by pre-configuring the UE with the capability to transmit scheduling information on HARQ feedback resources before actual transmission occurs. The network can configure the UE with scheduling information transmission parameters in advance, allowing the UE to efficiently utilize these resources when needed without requiring additional signaling or resource allocation delays.
3Device complexity
If traditional scheduling methods are used in NTN, then the scheduling protocol is simple, but the resource allocation efficiency and power consumption are poor
Solution Approach 1:
The patent applies self-service by enabling the UE to autonomously determine the optimal transmission method based on local conditions. The UE can decide whether to transmit scheduling information via HARQ feedback resources or PRACH based on its own buffer status and network conditions, without requiring complex network-controlled scheduling. This autonomous decision-making reduces network overhead and improves power efficiency.
Data Source
AI summary
This disclosure presents solutions for a IoT/eMTC over NTN communication system of a non-terrestrial network (NTN) node and a user equipment (UE) to determine whether and how scheduling information can be sent in the resources for a HARQ feedback, when the HARQ feedback is disabled. In some example embodiments, the UE can signal a buffer size. e.g., buffer status, by encoding the HARQ feedback and scheduling request (SR) utilizing two bits to provide the fast scheduling information. The NTN node can specify to the UE a set of HARQ parameters to provide an indication of HARQ feedback status, which can be disabling or enabling of HARQ feedback, and to provide an indication of the resources for transmission of HARQ feedback when the indication of HARQ feedback status is disabling.