Multi-Subframe Scheduling for Unlicensed Carrier Uplink
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Solution Overview
Problem
Current LTE systems face challenges in achieving high uplink transmission rates and performance due to the timing relationship between UL grant and data transmission, and lack effective solutions for multi-subframe scheduling on unlicensed carriers, particularly in scenarios involving multiple UEs.
Innovation Solution
The method involves scheduling information being sent to UEs in downlink subframes to manage UL data transmission on unlicensed carriers, allowing for multiple UEs to be scheduled across multiple UL subframes, either with a same set of UEs or different sets, using various scheduling methods such as broadcast, PDCCH, and ePDCCH, to optimize CCA and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UL grant is sent by base station to UE before UL data transmission with 4 ms timing relationship, then the system maintains proper timing synchronization, but the UL transmission rate becomes low
Solution Approach 1:
The patent segments the UL grant transmission into multiple parts: a first UL grant for initial transmission and a second UL grant for retransmission or additional resources. This segmentation allows the system to maintain timing synchronization for the first transmission while providing additional scheduling flexibility to improve overall UL transmission rate through retransmissions and adaptive resource allocation.
Solution Approach 2:
The base station performs preliminary actions by sending the first UL grant in advance with sufficient timing relationship (4 ms) to allow UE to prepare and transmit UL data. This preliminary scheduling ensures timing synchronization is maintained while the system can subsequently send additional grants to improve transmission rate through adaptive retransmissions.
2Ease of operation
If self-scheduling is used on unlicensed carrier, then the UE can autonomously perform CCA and transmit UL data, but the UL transmission rate remains low due to CCA contention failures
Solution Approach 1:
The patent implements feedback mechanisms where the base station monitors UL transmission outcomes and sends second UL grants based on feedback from CCA results and transmission status. This feedback loop allows the system to adaptively adjust scheduling decisions, providing additional UL grants when CCA failures occur, thereby maintaining autonomous CCA operation while improving overall UL transmission rate through adaptive retransmissions.
Solution Approach 2:
The scheduling system transitions from static single-grant scheduling to dynamic multi-grant scheduling. The base station dynamically decides whether to send a second UL grant based on real-time channel conditions, CCA results, and transmission status. This dynamic adaptation allows the system to maintain the simplicity of autonomous CCA while improving UL transmission rate through condition-based retransmissions.
3Productivity
If multi-subframe scheduling is implemented on unlicensed carrier, then the UL transmission rate can be improved, but the device complexity increases due to multiple scheduling scenarios
Solution Approach 1:
The patent creates a universal scheduling framework where a single base station and UE implementation can handle multiple scheduling scenarios (single-grant, multi-grant, different timing relationships, licensed and unlicensed carriers) through a unified mechanism. The base station uses a universal decision logic that adapts to different scenarios by selectively applying appropriate grant transmission strategies, thereby improving UL transmission rate across multiple scenarios without proportionally increasing device complexity.
Solution Approach 2:
The system manages complexity by changing key parameters dynamically rather than implementing separate mechanisms for each scenario. The base station adjusts parameters such as the number of UL grants to send, timing relationships, and carrier selection based on channel conditions and traffic requirements. This parameter-based adaptation allows multi-subframe scheduling to improve UL transmission rate while keeping device complexity manageable through a unified configurable framework.
4Productivity
If multiple UEs are scheduled in continuous subframes, then resource utilization improves, but the scheduling complexity increases due to multi-user multiplexing requirements
Solution Approach 1:
The patent segments the multi-UE scheduling problem by handling each UE's grant transmission independently through a unified framework. The base station processes scheduling decisions for multiple UEs in continuous subframes by applying the same multi-grant logic to each UE separately, thereby improving overall resource utilization while managing complexity through modular, UE-independent processing rather than complex inter-UE coordination.
Solution Approach 2:
The base station applies partial scheduling action by sending UL grants to only those UEs that need retransmission or additional resources, rather than uniformly scheduling all UEs in all subframes. This selective application of multi-grant scheduling to UEs that benefit most from it improves resource utilization for active users while limiting complexity increases to only the necessary scheduling operations.
Data Source
AI summary
The present invention provides a data transmission method, comprising: sending scheduling information to a terminal on a downlink subframe, wherein the scheduling information is used for scheduling the terminal to transmit uplink data on one or more uplink subframes of an unlicensed carrier; and receiving the uplink data transmitted by the terminal. The present invention provides a technical solution of multi-subframe scheduling in the unlicensed carrier which does not exist in the prior art. The present invention also provides a data transmission device and a storage medium.