Low-Capability Device Downlink Control Channel Reception
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Solution Overview
Problem
Low-cost/low-capability devices in machine-type communication (MTC) struggle to properly receive the existing Physical Downlink Control Channel (PDCCH) transmitted over the entire system band, due to their limited capabilities and cost constraints, which affects their ability to decode control information efficiently.
Innovation Solution
A method and device for receiving a downlink control channel, where a low-cost/low-capability device determines a search space for monitoring the downlink control channel by defining candidates based on aggregation and repetition levels, with each candidate repeated across multiple consecutive subframes, and uses a radio resource control (RRC) signal to determine the start subframe, allowing for efficient decoding of the control channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If MTC devices use only a subband of about 1.4 MHz to reduce cost, then device cost is reduced, but the ability to receive PDCCH transmitted over the entire system band is lost
Solution Approach 1:
The system bandwidth is segmented into multiple subbands, with each MTC device configured to monitor a specific subband for PDCCH transmissions. This allows low-cost devices to operate in reduced bandwidth while the base station transmits control channels across the entire system band, ensuring both cost reduction and reliable reception
Solution Approach 2:
Different subbands are allocated to different MTC devices based on their specific requirements and capabilities. Each device receives PDCCH transmissions tailored to its configured subband, optimizing the local reception quality for that specific frequency range while maintaining overall system efficiency
2Adaptability or versatility
If PDCCH is transmitted over the entire system band, then control information coverage is maximized, but low-cost devices cannot properly receive it due to limited capabilities
Solution Approach 1:
The system dynamically configures MTC devices to monitor specific subbands for PDCCH based on device capabilities, channel conditions, and traffic requirements. This dynamic adaptation allows the system to maintain full control information coverage while ensuring each device receives transmissions within its operational capabilities
Solution Approach 2:
The base station changes transmission parameters such as subband allocation, aggregation level, and repetition factor based on the specific needs of each MTC device. This parameter adaptation ensures that control information is transmitted in a format that low-cost devices can properly receive and decode
3Reliability
If low-cost devices monitor PDCCH in the entire system band, then reception capability is improved, but device complexity and cost increase
Solution Approach 1:
The function of monitoring the entire system band for PDCCH is extracted from low-cost MTC devices and relocated to the base station. The base station handles the complex task of transmitting and managing PDCCH across the full bandwidth, while devices only need to monitor their configured subbands, significantly reducing device complexity
Solution Approach 2:
The base station acts as an intermediary that manages the PDCCH transmissions across the entire system band and translates this into device-specific subband configurations. This intermediary function allows low-cost devices to receive control information reliably without needing to implement complex full-band monitoring capabilities
Data Source
AI summary
The disclosure of the present specification provides a method for receiving a downlink control channel in a low-capability (LC) or low-cost (LC) apparatus. The method may comprise a step of determining a search space for monitoring the downlink control channel, wherein the search space can be defined by a candidate of the downlink control channel according to a set level and a repetition level. Each candidate can be repeated on a plurality of consecutive subframes which start from a start subframe. The location of the start subframe can be determined by a value obtained from an RRC signal. The method may comprise a step of decoding each candidate of the downlink control channel repeated on the consecutive subframes.