Cross-Carrier Scheduling HARQ Timing in TDD Systems
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Solution Overview
Problem
The challenge in LTE Advanced systems is to maximize the use of existing HARQ timing relationships for cross-carrier scheduling while maintaining low device complexity, especially when different carriers have different uplink/downlink proportion configurations.
Innovation Solution
The method involves a base station sending uplink scheduling grant signaling and ACK/NACK feedback signaling on a carrier m, while receiving uplink data through a Physical Uplink Shared Channel (PUSCH) on a carrier n, with a timing relationship that aligns with the HARQ timing corresponding to the uplink/downlink configuration of either carrier, ensuring efficient cross-carrier scheduling and Enhanced Inter-Cell Interference Coordination (EICIC) without increasing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cross-carrier scheduling is implemented with different uplink/downlink configurations on different carriers, then resource utilization efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by allowing different carriers to have different uplink/downlink configuration parameters while maintaining a unified HARQ timing relationship. The base station determines the timing relationship based on the configuration of the scheduling carrier (carrier m) rather than requiring each carrier to have identical configurations, thus enabling resource utilization efficiency improvement without proportionally increasing device complexity
Solution Approach 2:
The patent implements universality by creating a universal HARQ timing relationship that can accommodate multiple carriers with different uplink/downlink configurations. The timing relationship serves multiple carriers simultaneously, allowing cross-carrier scheduling to work across carriers with diverse configurations without requiring carrier-specific timing handling, thereby improving resource utilization while controlling complexity
2Productivity
If HARQ timing relationship is aligned with uplink/downlink configuration of scheduling carrier, then cross-carrier scheduling efficiency is improved, but timing coordination difficulty increases
Solution Approach 1:
The patent applies feedback by having the base station determine the HARQ timing relationship based on the uplink/downlink configuration of the scheduling carrier (carrier m), and then use this timing relationship to coordinate ACK/NACK feedback for carriers n. This feedback mechanism allows the system to adapt the timing relationship to the scheduling carrier's configuration, improving scheduling efficiency while the base station's centralized determination simplifies timing coordination complexity
Data Source
AI summary
A base station, a terminal, a system and methods for performing data transmission in a Time Division Duplex (TDD) system are disclosed. One of the methods includes: the base station sending an uplink scheduling grant signaling to the terminal on a carrier m, and after receiving uplink data sent by the terminal through a Physical Uplink Shared Channel (PUSCH) on a carrier n, the base station sending an ACK/NACK feedback signaling corresponding to the PUSCH to the terminal on the carrier m; wherein, m≠n; a timing relationship between a subframe by which the base station sends the uplink scheduling grant signaling and/or the ACK/NACK feedback signaling and a subframe where the PUSCH is located is identical with a Hybrid Automatic Repeat Request (HARQ) timing relationship corresponding to an uplink/downlink configuration of the carrier m or the carrier n.