Multi-Subframe Cross-Carrier Scheduling for Heterogeneous Networks
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Solution Overview
Problem
In 3GPP LTE networks, cross-carrier scheduling is limited to downlink grant information applicable only to subframes where the control information is transmitted, complicating resource allocation in heterogeneous networks with different TDD UL-DL configurations, especially when conventional mechanisms fail to transmit DL grant information in the same subframe.
Innovation Solution
Implementing multi-subframe cross-carrier scheduling (MSCC) that allows DCI transmitted in a first subframe of the Pcell to be applicable to a second subframe in an Scell, using predetermined subframe pairings to maintain processing latency and avoid increasing DCI overhead, even with different TDD UL-DL configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cross-carrier scheduling is implemented to transmit DL grant information in a different component carrier, then control reliability is improved, but device complexity increases due to different TDD UL-DL configurations
Solution Approach 1:
The patent segments the scheduling process by introducing separate uplink and downlink association indicators (UL DAI and DL DAI) that independently track resource allocation in each direction. This segmentation allows the system to handle different TDD configurations across component carriers without requiring complex inter-dependent scheduling logic, thereby reducing device complexity while maintaining control reliability through precise resource tracking.
Solution Approach 2:
The patent implements preliminary action by pre-defining the relationship between downlink subframes and uplink subframes through downlink association indicator (DAI) values. The DAI is prepared in advance in the downlink grant and indicates the corresponding uplink subframe for feedback transmission. This preliminary establishment of associations simplifies the scheduling complexity by eliminating the need for dynamic calculation of subframe relationships during operation.
2Adaptability or versatility
If multi-subframe cross-carrier scheduling is implemented to allow DCI in one subframe to schedule another subframe, then resource allocation flexibility is improved, but processing latency increases
Solution Approach 1:
The patent implements dynamics by making the subframe association relationship configurable rather than fixed. The downlink association indicator (DAI) dynamically indicates different uplink subframes based on the specific scheduling requirements and TDD configurations. This dynamic association allows the system to adapt to different scenarios (same-subframe or different-subframe scheduling) without incurring excessive processing latency, as the appropriate association can be selected based on real-time conditions.
3Loss of time
If conventional cross-carrier scheduling is used where DL grant information applies only to the same subframe, then processing latency is reduced, but adaptability to different TDD configurations deteriorates
Solution Approach 1:
The patent implements universality by designing the downlink association indicator (DAI) mechanism to serve multiple functions simultaneously. The DAI can indicate uplink subframes for both same-subframe scheduling (when K=0) and different-subframe scheduling (when K>0). This multi-functional design allows the system to maintain low processing latency for time-sensitive applications while simultaneously providing adaptability to different TDD configurations, eliminating the need for separate scheduling mechanisms for different scenarios.
Data Source
AI summary
Embodiments of the present disclosure describe devices, methods, computer-readable media and systems configurations for downlink resource scheduling in wireless networks. In some embodiments, the scheduling may include multi-subframe cross carrier scheduling utilizing downlink control information. Other embodiments may be described and/or claimed.