PDCCH Span Distribution for Cross-Carrier DCI Decoding Timing
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Solution Overview
Problem
In wireless communication systems with cross carrier scheduling, the subcarrier spacing difference between scheduling and scheduled cells impairs the user equipment's ability to timely decode downlink control indicators (DCIs) and subsequent user data traffic, leading to delays in ACK/NACK reports.
Innovation Solution
The PDCCH is divided into multiple spans within the scheduling slot to distribute DCIs in time and frequency, allowing quicker decoding by the scheduled entities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If downlink control information is transmitted on the same carrier as data, then transmission simplicity is maintained, but interference between control and data channels increases and resource flexibility is limited
Solution Approach 1:
The patent segments the control and data transmission by separating them onto different carriers. The downlink control information is transmitted on a first carrier while data is transmitted on a second carrier, physically dividing the transmission resources to eliminate mutual interference and improve control channel reliability.
Solution Approach 2:
The patent introduces a distributed unit as an intermediary component that receives control information from the network device and forwards it to the terminal device. This intermediary enables flexible resource allocation across multiple carriers while maintaining clear separation between control and data planes.
2Device complexity
If control resources are fixed on a single carrier, then resource allocation simplicity is maintained, but resource utilization efficiency decreases
Solution Approach 1:
The patent enables control resources to be universally allocated across multiple carriers. The network device can flexibly assign control information to different carriers based on channel conditions and traffic requirements, making the resource allocation system multi-functional and adaptable to various scenarios.
Solution Approach 2:
The patent implements dynamic resource allocation where the carrier used for control information transmission can change based on real-time network conditions. The network device dynamically selects which carrier to use for control plane transmission, optimizing resource utilization efficiency while maintaining manageable complexity through standardized procedures.
3Device complexity
If control and data use the same time-frequency resources, then resource allocation is simplified, but channel interference increases
Solution Approach 1:
The patent physically segments control and data transmissions by assigning them to different carriers in the frequency domain. This spatial separation eliminates the harmful interference that would occur if control and data shared the same time-frequency resources, while resource management remains simplified through standardized carrier assignment procedures.
Data Source
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AI summary
Aspects relate to wireless communications utilizing cross carrier scheduling Methods and apparatus include generating at least one slot in a control channel from a scheduling cell, the at least one slot including a plurality of control channel segments such as PDCCH segments, which are arranged at respective times within the at least one slot. Each of the control channel segments includes control information such as DCIs corresponding to respective slots for a scheduled cell. Distributing the control channel information in segments or spans over time affords improved decoding timing in a UE in the scheduled cell.