HARQ Subset Configuration for Delay-Tolerant Wireless Transmissions
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Solution Overview
Problem
Error control procedures in wireless networks with large propagation delays, such as non-terrestrial networks, face challenges due to increased latency, memory requirements, reduced transport block sizes, and signaling overhead when multiple HARQ processes are activated, while disabling these procedures leads to packet loss and higher layer retransmissions.
Innovation Solution
Implementing parameter configurations for subsets of HARQ processes where feedback is enabled or disabled, allowing different transmission parameters for each subset, including aggregation factor, modulation and coding scheme, and resource allocation, to optimize data transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple HARQ processes are activated simultaneously to cope with large propagation delays, then the error control mechanism can handle larger delays, but it requires large memories at transmitter and receiver, reduces maximum transport block size, and increases signaling overhead
Solution Approach 1:
The patent segments HARQ processes into two distinct subsets: a first subset with HARQ feedback enabled and a second subset with HARQ feedback disabled. This segmentation allows the system to apply different parameter configurations to each subset, enabling the use of multiple HARQ processes for delay tolerance while avoiding the need to increase memory size for all processes. The segmented approach selectively activates feedback only where needed, reducing overall memory requirements while maintaining error control capability.
2Reliability
If multiple HARQ processes are activated simultaneously, then propagation delay tolerance improves, but signaling overhead increases
Solution Approach 1:
The patent extracts the HARQ feedback mechanism from the entire set of HARQ processes and applies it only to a specific first subset of processes where it is truly needed. By taking out the feedback requirement from the second subset of processes, the system reduces signaling overhead while maintaining delay tolerance through the parallel operation of multiple HARQ processes. This extraction eliminates unnecessary feedback signaling for processes where delay tolerance is the primary concern rather than error control.
3Reliability
If HARQ feedback is enabled for all HARQ processes, then error control is improved, but latency increases due to stop-and-wait mechanism
Solution Approach 1:
The patent introduces dynamic configurability to HARQ processes by allowing the network to independently enable or disable HARQ feedback for each process in the first and second subsets. This dynamic approach allows the system to adaptively select whether to use feedback-based error control or pure throughput-oriented transmission based on current channel conditions and service requirements, thereby optimizing the trade-off between error control and latency on a per-process basis rather than applying a static configuration to all processes.
Data Source
AI summary
Embodiments include methods for a wireless device. Such methods can include receiving, from a network node in a wireless network, control signaling that indicates a parameter configuration for data transmissions, by the network node or by the wireless device, that are associated with a subset of a plurality of hybrid ARQ, HARQ, processes. The indicated parameter configuration can be one of a plurality of parameter configurations corresponding to a respective plurality of different subsets of the HARQ processes. The different subsets can include a first subset of one or more HARQ processes for which HARQ feedback is disabled, and a second subset of one or more HARQ processes for which HARQ feedback is enabled. Other embodiments include complementary methods for a network node in a wireless network, and wireless devices and network nodes configured to perform the respective methods.