eLAA PDCCH Signaling for Multi-Subframe HARQ Scheduling
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Solution Overview
Problem
Existing Licensed Assisted Access (LAA) and enhanced LAA (eLAA) wireless communication systems face challenges in maintaining reliable uplink communication over unlicensed spectrum, particularly in efficiently scheduling Physical Uplink Shared Channel (PUSCH) transmissions with Hybrid Automatic Retransmission (HARQ) support, due to limitations in signaling overhead and subframe scheduling flexibility.
Innovation Solution
A flexible and efficient Physical Downlink Control Channel (PDCCH) signaling scheme is introduced, which schedules PUSCH transmissions over multiple subframes with support for multiple non-consecutive Hybrid Automatic Retransmission (HARQ) processes, using joint signaling to combine HARQ process indexes, new data indication, and redundancy version to reduce signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional PDCCH signaling is used for scheduling PUSCH transmissions in LAA, then the system can maintain basic uplink communication, but signaling overhead increases and scheduling flexibility decreases
Solution Approach 1:
The patent combines multiple signaling functions into a single DCI format. Specifically, it merges the scheduling indication for multiple PUSCH transmissions, HARQ process information, and uplink grant details into one consolidated downlink control information message, thereby reducing the number of separate signaling messages and overall overhead
Solution Approach 2:
The DCI format is designed to serve multiple functions simultaneously: it schedules PUSCH transmissions across multiple subframes, manages multiple HARQ processes, and provides uplink grants all through a single signaling structure, making the signaling mechanism multi-functional and more efficient
2Productivity
If multiple HARQ processes are used for PUSCH transmissions over multiple subframes, then throughput improves, but system complexity increases
Solution Approach 1:
The patent segments the HARQ process management by assigning different HARQ process IDs to different subframes or transmission groups. This segmentation allows the system to handle multiple concurrent HARQ processes in an organized manner, improving throughput while managing complexity through structured division of processes
Solution Approach 2:
The system dynamically allocates and manages HARQ processes based on transmission needs. The DCI format enables dynamic indication of which HARQ processes are active in which subframes, allowing the system to adaptively control the number and configuration of HARQ processes rather than maintaining a fixed complex structure
3Adaptability or versatility
If flexible timing between UL grant and PUSCH subframes is supported, then adaptability improves, but scheduling complexity increases
Solution Approach 1:
The patent introduces a time dimension parameter in the DCI format that explicitly indicates the timing relationship between UL grant and PUSCH transmissions. By adding this temporal dimension parameter, the system achieves flexible scheduling across multiple subframes while managing complexity through a standardized parameter-based approach rather than complex procedural logic
Data Source
AI summary
A flexible and efficient physical downlink control channel (PDCCH) signaling scheme that schedules physical uplink shared channel (PUSCH) transmission over multiple subframes with Hybrid Automatic Retransmission (HARQ) support is proposed. The PDCCH has a downlink control information (DCI) format that schedules PUSCH transmission over multiple subframes. The PUSCH transmission is associated with multiple HARQ processes with non-consecutive HARQ process IDs. Furthermore, the DCI format uses joint signaling to combine HARQ process indexes, new data indication (NDI), and redundancy version (RV) to reduce signaling overhead.