PDCCH Indicator for Aperiodic Reference Signal Transmission
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Solution Overview
Problem
Wireless communication systems face challenges in efficiently transmitting and indicating reference signals in unlicensed bands, leading to channel measurement failures due to periodic signal transmission constraints.
Innovation Solution
A method is introduced where a physical downlink control channel (PDCCH) includes an indicator in its downlink control information (DCI) to notify user equipment (UE) about the aperiodic transmission of reference signals (RS) in the unlicensed band, allowing efficient channel measurement by decoding the presence or absence of RS during specific time intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reference signals are periodically transmitted in unlicensed bands, then channel measurement can be performed regularly, but transmission failures occur due to lack of transmission indication
Solution Approach 1:
The patent applies preliminary action by transmitting an indicator in advance within the licensed band PDCCH to notify UE of upcoming reference signal transmissions in the unlicensed band. This allows UE to prepare for channel measurement before the actual RS transmission occurs, preventing measurement failures due to unexpected transmission absence.
Solution Approach 2:
The patent uses an indicator field in DCI as an intermediary element that bridges the licensed band control channel and unlicensed band data transmission. This intermediary carries transmission indication information that coordinates between the base station's RS transmission decisions and the UE's channel measurement operations across different frequency bands.
2Productivity
If reference signals are transmitted aperiodically in unlicensed bands, then transmission efficiency is improved, but UE cannot determine whether RS is transmitted for accurate channel measurement
Solution Approach 1:
The patent implements feedback by providing transmission indication information from the base station to the UE through the indicator field. This feedback mechanism allows UE to accurately determine whether reference signals are transmitted in aperiodic mode, enabling precise channel measurement while maintaining the transmission efficiency benefits of aperiodic signaling.
3Measurement precision
If indicator is added to DCI to indicate RS transmission, then channel measurement accuracy is improved, but control information overhead increases
Solution Approach 1:
The patent applies universality by designing the indicator field to serve multiple functions: it indicates reference signal transmission status, enables channel measurement accuracy, and works across both licensed and unlicensed band scenarios. This multi-functionality justifies the overhead by providing comprehensive control capabilities rather than requiring separate mechanisms for each function.
Data Source
AI summary
The embodiments of the present invention relate to a method for transmitting control information by a base station in a wireless communication system, wherein the method comprises a step of transmitting a physical downlink control channel (PDCCH). The downlink control information of the PDCCH may include an indicator indicating whether or not a reference signal is transmitted in a time domain corresponding to the subframe in which the PDCCH is transmitted.