HD-FDD RX-TX Switching Timing for NTN UL Scheduling
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Solution Overview
Problem
In half-duplex frequency division duplexing (HD-FDD) mode, particularly in Non-Terrestrial Networks (NTNs) using high frequency ranges like FR2, the large frequency difference between downlink (DL) and uplink (UL) frequencies leads to prolonged convergence times for carrier frequency switching, preventing simultaneous transmission and reception on consecutive slots.
Innovation Solution
Wireless devices and network entities implement mechanisms to indicate a minimum time required for switching between DL and UL frequencies, allowing scheduled communications to accommodate these transition times, ensuring appropriate scheduling and avoiding excessive gaps between transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If HD-FDD mode is used with large frequency difference between DL and UL, then frequency division duplexing is achieved, but carrier frequency switching convergence time is prolonged
Solution Approach 1:
The patent applies preliminary action by having the UE indicate its switching capability (minimum switching time) in advance before actual frequency switching occurs. This capability indication is provided during setup or reconfiguration, allowing the network to pre-calculate appropriate scheduling timelines that accommodate the UE's specific switching requirements, thereby reducing actual switching delays.
Solution Approach 2:
The patent implements dynamics by making the scheduling timeline adaptive rather than fixed. The network dynamically adjusts the timing of UL transmissions based on the UE's indicated switching capability. When a UE indicates a longer minimum switching time, the network schedules UL transmissions accordingly, creating a dynamic scheduling mechanism that adapts to different UE capabilities and frequency differences.
2Productivity
If minimum switching time is indicated and scheduled transmissions are adjusted, then transmission scheduling is optimized, but transmission timing flexibility is reduced
Solution Approach 1:
The patent applies parameter changes by modifying the scheduling parameters (time timeline) based on the UE's indicated switching capability. Instead of using a fixed scheduling approach, the system changes the timing parameters dynamically according to the UE's capability indication. This allows the network to adjust transmission schedules to match actual UE switching capabilities while maintaining scheduling efficiency.
Solution Approach 2:
The patent implements feedback by having the UE provide capability indication information about its switching time requirements. This feedback mechanism allows the network to understand the UE's actual switching capabilities and adjust scheduling accordingly. The feedback loop ensures that scheduling decisions are based on real UE capabilities rather than assumptions, optimizing both efficiency and adaptability.
3Adaptability or versatility
If frequency switching is enabled for HD-FDD, then communication mode switching is achieved, but switching time gaps between modes increase
Solution Approach 1:
The patent applies preliminary action by having the UE indicate its switching capability in advance, allowing the network to pre-schedule transmissions that account for the required switching time. This prevents last-minute scheduling adjustments that would create unnecessary gaps, instead establishing optimal timelines beforehand based on the UE's indicated capabilities.
Solution Approach 2:
The patent implements parameter changes by adjusting the scheduling timeline parameter based on the UE's switching capability indication. When a UE indicates a specific minimum switching time, the network changes the scheduling parameters to accommodate this requirement, thereby optimizing the switching time gap rather than using a fixed, potentially excessive gap for all UEs.
Data Source
AI summary
The apparatus configured to transmit, to a network device, a first indication of a minimum time associated with switching between a first frequency used for DL communication and a second frequency used for UL communication, receive, from the network device via the first frequency, a second indication scheduling an UL communication at a time that is no sooner than the minimum time after the second indication is received, switch from the first frequency to the second frequency based on the second indication, and transmit the scheduled UL communication via the second frequency.