NTN MTC Scheduling with Common Timing Advance
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Solution Overview
Problem
Wireless communication networks, particularly non-terrestrial networks (NTNs), face challenges with high-latency links that complicate communication, especially in machine type communications (MTC) due to propagation time delays and frequency shifts, which are exacerbated by satellite movements and large distances.
Innovation Solution
Implementing techniques to adjust scheduling timing and enhance uplink and downlink transmissions in NTN by using timing advance (TA) adjustments, reducing TA report signaling overhead, configuring variable uplink transmission times, and employing enlarged compensation gaps to maintain synchronization, thereby preventing uplink-downlink interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If timing advance adjustments and scheduling optimizations are implemented to maintain synchronization in NTN, then communication reliability is improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent changes the timing advance parameter from a dynamic per-UE value to a common TA value for all UEs in the NTN cell. This parameter change simplifies the scheduling complexity by eliminating the need for individual TA calculations and reports, while maintaining communication reliability through the common timing reference provided by the satellite
Solution Approach 2:
The patent applies a universal common TA value to all user equipments in the NTN cell, making the timing advance mechanism applicable to the entire cell rather than individual UEs. This universal approach reduces signaling overhead and scheduling complexity while ensuring synchronized uplink transmissions across all users
2Loss of energy
If timing advance reports are reduced to lower signaling overhead, then network efficiency is improved, but uplink synchronization precision may deteriorate
Solution Approach 1:
The patent extracts the timing advance reporting function from individual UE-level operations and relocates it to the satellite-level common reference. By removing the need for UE-specific TA reports and instead using a common TA value broadcast by the satellite, signaling overhead is dramatically reduced while synchronization precision is maintained through the satellite's centralized timing management
Solution Approach 2:
The satellite acts as an intermediary that provides a common timing reference to all UEs, eliminating the need for direct UE-to-network TA reporting. This intermediary approach reduces signaling overhead by centralizing timing management at the satellite level while maintaining synchronization precision through the intermediary's coordinated control
3Adaptability or versatility
If variable uplink transmission times are configured to accommodate satellite movement, then communication adaptability is improved, but scheduling complexity increases
Solution Approach 1:
The patent implements dynamic scheduling adaptability by configuring variable contiguous uplink transmission time lengths based on satellite movement characteristics. The system dynamically adjusts the uplink transmission time window to accommodate changing propagation delays while the satellite moves, providing adaptability without requiring complex real-time TA adjustments for each UE
Solution Approach 2:
The patent applies preliminary action by pre-configuring variable uplink transmission time parameters before uplink transmissions occur. The network pre-configures different uplink time length values that account for anticipated satellite movement, allowing UEs to adapt to orbital mechanics in advance rather than requiring complex real-time scheduling adjustments
Data Source
AI summary
Apparatus and methods are provided to enhance communications for NTN. In some aspects, a base station (BS) comprises a processor configured to schedule an uplink transmission in response to an uplink transmission request from a user equipment (UE) using one or more subframes ranging from a first uplink subframe to a last uplink subframe. The processor is further configured to determine or receive a timing advance (TA) indicating amount of subframes transmitted during a time delay between the UE and the BS and schedule a downlink transmission aligned with the uplink transmission. The downlink transmission is blocked from subframes ranging from TA plus one or more subframes ahead of the first uplink subframe to TA minus one or more subframes ahead of the last uplink subframe. The processor is further configured to transmit and receive, via a non-terrestrial equipment, the uplink and the downlink.