LEO Satellite TDD Frame Offsetting for Guard Period Reuse
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Solution Overview
Problem
The existing TDD system for low earth orbit (LEO) satellite communication suffers from low spectrum utilization due to long guard periods, limited resource utilization, and potential UE-to-UE co-channel cross-link interference, especially in scenarios where different satellite-borne base stations communicate with UEs during GP slots, leading to inefficient resource allocation and strict time synchronization requirements.
Innovation Solution
A satellite communication method and apparatus based on a time division duplex (TDD) frame structure design, which involves determining a preset TDD frame structure group comprising a first and second TDD frame structure, allowing UEs to be scheduled differently based on their sets, enabling simultaneous communication during GP periods and utilizing subband full duplex technology to mitigate interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If TDD mode is adopted to improve spectrum utilization, then spectrum utilization rate is improved, but guard period duration increases causing resource utilization to decrease
Solution Approach 1:
The system divides UEs into different sets (first UE set and second UE set) and assigns different TDD frame structures to each set. This segmentation allows the base station to schedule different UEs in different time slots, effectively utilizing the guard period for additional communications rather than leaving it idle, thereby reducing the effective guard period duration while maintaining TDD mode benefits.
Solution Approach 2:
The system dynamically schedules UEs by determining their belonging to different UE sets based on channel conditions and traffic requirements. This dynamic scheduling allows flexible allocation of time resources, enabling the system to adaptively use guard period slots for data transmission when appropriate, thus reducing wasted time while maintaining high spectrum utilization.
2Productivity
If different NTN cells use GP slots for data reception and transmission, then resource utilization is improved, but only one satellite-borne base station can communicate at a time causing system-wide utilization to remain low
Solution Approach 1:
The patent makes the guard period slot serve multiple functions: it acts as a guard period for some UEs while simultaneously serving as a data transmission slot for other UEs in different UE sets. This multi-functionality allows the same time resource to be productively used by multiple satellite-borne base stations simultaneously, improving system-wide utilization without requiring complex inter-base station coordination.
Solution Approach 2:
The system introduces a new dimension of differentiation by creating multiple TDD frame structures with different timing configurations. Instead of all base stations using identical frame structures, the system employs frame header offsetting to create staggered timing, allowing simultaneous communications in what would traditionally be guard periods, thereby improving utilization without increasing synchronization complexity.
3Productivity
If frame header offsetting is performed to create second TDD frame structure, then air interface resource utilization is improved, but UE set classification and scheduling complexity increases
Solution Approach 1:
The system performs preliminary classification of UEs into different sets based on their channel characteristics and service requirements before scheduling. This advance classification simplifies the scheduling process by pre-organizing UEs into groups that can be served by different TDD frame structures, reducing the complexity of real-time decision-making while maximizing resource utilization.
Data Source
AI summary
The present disclosure provides a satellite communication method and apparatus based on a time division duplex (TDD) frame structure design. The solution is: determining a preset time division duplex (TDD) frame structure group corresponding to a base station, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated after frame header offsetting is performed on the first TDD frame structure; in response to receiving a first message transmitted by a terminal, determining a UE set to which the terminal belongs, wherein the UE set is a first UE set or a second UE set; if the terminal belongs to the first UE set, scheduling the terminal based on the first TDD frame structure; and if the terminal belongs to the second UE set, scheduling the terminal based on the second TDD frame structure.