Cross-Carrier Scheduling for Shortened TTIs in Wireless Networks
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently scheduling resources for low latency communications using shortened transmission time intervals (TTIs) across multiple component carriers, particularly in managing inter-cell interference and supporting legacy users.
Innovation Solution
A method and apparatus for cross-carrier scheduling that involves identifying different TTI durations for component carriers, transmitting scheduling information for resource allocation, and using a primary component carrier to convey scheduling details for multiple carriers, including both common and UE-specific information, to optimize resource utilization and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cross-carrier scheduling is used to allocate sTTI resources across multiple component carriers, then resource allocation efficiency is improved, but inter-cell interference increases due to coordinated scheduling requirements
Solution Approach 1:
The patent segments sTTI resource allocation into separate groups based on TTI duration (e.g., Group 1 for 2OS sTTI, Group 2 for 7OS sTTI). Each group operates with independent scheduling, allowing base stations to manage interference within groups while maintaining efficient resource allocation. This segmentation resolves the contradiction by enabling cross-carrier scheduling within groups (improving efficiency) while reducing inter-group interference (mitigating harmful factors).
Solution Approach 2:
The patent applies different scheduling configurations to different component carriers based on their specific TTI duration requirements. Each component carrier or group of carriers can have customized scheduling parameters, allowing optimal local resource allocation while managing interference characteristics specific to each carrier group. This local quality approach enables efficient cross-carrier scheduling where needed while minimizing interference in sensitive areas.
2Adaptability or versatility
If multiple TTI durations are configured across component carriers, then support for both low latency and legacy communications is improved, but scheduling complexity increases
Solution Approach 1:
The patent divides component carriers into distinct groups based on TTI duration configurations. Group 1 carriers use shorter TTI durations for low latency services, while Group 2 carriers use longer TTI durations for legacy communications. This segmentation allows the system to support multiple communication requirements simultaneously while simplifying scheduling within each group, as each group can be managed with its own scheduling rules rather than requiring complex unified scheduling across all carriers.
Solution Approach 2:
The patent creates a multi-functional scheduling framework where the base station can apply different scheduling strategies to different carrier groups based on service requirements. The same base station infrastructure handles both low latency and legacy communications by applying appropriate scheduling configurations to different groups, achieving universality without requiring separate systems for each communication type.
3Reliability
If sTTI resources are concentrated on specific component carriers, then low latency service quality is improved, but resource utilization across the network decreases
Solution Approach 1:
The patent merges sTTI resource allocation across multiple component carriers by creating groups that can be scheduled together. Instead of concentrating sTTI resources on a single carrier, the system combines resources from multiple carriers within the same group, allowing low latency services to utilize aggregated resources while maintaining service quality. This merging approach improves overall resource utilization while preserving the reliability needed for low latency communications.
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described in which scheduling of time and frequency resources for multiple component carriers (CCs) may be provided in a low latency physical downlink control channel (sPDCCH) transmission to a user equipment (UE). The scheduling information may include a first portion that is transmitted during a first transmission time interval (TTI) and that includes scheduling information (UE-specific or common for multiple UEs) for two or more shortened TTIs (sTTIs) on one or more CCs, and a second portion that may be specific to the particular sTTI on one or more CCs. Rate matching information may be provided to indicate portions of the sPDCCH that may be reallocated for shared channel transmissions. The scheduling information may be, in some cases, provided in a single-level scheduling information transmission for two or more UEs, that provides UE-specific resources on one or more CCs.