NTN MAC Control Element Timing for HARQ Feedback Delays
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Solution Overview
Problem
Existing medium access control (MAC) protocols in non-terrestrial networks (NTNs) face challenges in efficiently managing communication timing and resource allocation due to the unique characteristics of satellite-based communication, such as high latency and mobility, leading to suboptimal performance and increased latency.
Innovation Solution
Adaptive MAC timing mechanisms are introduced to align with the specific characteristics of NTNs, including dynamic adjustment of transmission timing and resource allocation based on network conditions, leveraging advanced signaling and feedback mechanisms to optimize communication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If existing MAC protocols are used in NTNs, then device compatibility is maintained, but communication latency increases and efficiency deteriorates
Solution Approach 1:
The patent implements dynamic MAC timing adjustment mechanisms that adapt transmission timing, slot structures, and resource allocation based on real-time satellite position, mobility state, and channel conditions. This transforms the static MAC protocol into a dynamic system that can optimize performance for different NTN scenarios including LEO, MEO, and GEO satellites.
Solution Approach 2:
The patent modifies key MAC layer parameters including timing advance values, slot durations, subcarrier spacings, and resource allocation patterns to account for NTN-specific characteristics such as high latency, Doppler shifts, and mobility. These parameter changes enable the MAC protocol to function effectively in satellite environments while maintaining compatibility with existing 5G NR frameworks.
2Productivity
If adaptive MAC timing mechanisms are implemented, then communication efficiency improves and latency reduces, but system complexity increases
Solution Approach 1:
The patent pre-configures multiple MAC parameter sets and timing adjustment tables that are prepared in advance for different satellite types, mobility states, and channel conditions. These pre-configured parameters are stored in UE and gNB memory, allowing rapid selection and application without complex real-time calculations, thereby reducing processing complexity while maintaining adaptability.
Solution Approach 2:
The patent implements feedback mechanisms where UEs report channel quality, timing synchronization status, and mobility state information to gNB. The gNB uses this feedback to dynamically adjust MAC parameters and timing configurations. This closed-loop feedback system enables adaptive optimization without requiring overly complex open-loop prediction algorithms.
3Reliability
If dynamic timing adjustment is performed, then resource allocation optimizes for satellite characteristics, but signaling overhead increases
Solution Approach 1:
The patent designs MAC control elements and signaling messages that serve multiple functions simultaneously. For example, timing advance commands also convey uplink synchronization status, resource allocation messages include both scheduling decisions and parameter configurations, and feedback reports provide both channel quality and timing synchronization information. This multi-functionality reduces the number of separate signaling messages required.
Solution Approach 2:
The patent combines multiple MAC layer functions and information elements into unified signaling structures. Resource allocation messages integrate timing configuration, resource grant, and parameter settings into single transmissions. Feedback mechanisms combine channel quality reports, timing status, and mobility information into consolidated uplink messages, thereby reducing overall signaling overhead while maintaining comprehensive control.
Data Source
AI summary
A wireless device receives a packet corresponding to a hybrid automatic repeat request (HARQ) process, wherein the packet comprises a medium access control (MAC) control element (CE). Based on whether a feedback of the HARQ process being enabled or disabled, the wireless device applies the MAC CE after at least one of: a first time duration starting from transmission of feedback of the packet; or a second time duration starting from reception of the packet.