Subframe Repetition Index for MTC Coverage Enhancement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication protocols, such as those for 3GPP LTE, are not optimally suited for Machine-Type Communication (MTC) due to high power consumption and cost, and lack efficient mechanisms for low-bandwidth, low-cost, and coverage-enhanced user equipment (UEs), particularly in scenarios requiring infrequent, small-burst transmissions and deep building coverage.
Innovation Solution
The method involves a communication device that receives and transmits downlink transmissions across multiple subframes using a repetition or bundling mechanism, indicated by a repetition index and set indicator, allowing for flexible modulation and coding schemes and transport block sizes, which are signaled through higher-layer control information, enabling efficient communication with reduced RF bandwidth and supporting low-cost, coverage-enhanced UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If standard 3GPP LTE protocols are used for MTC, then communication functionality is provided, but power consumption and device cost are high
Solution Approach 1:
The patent segments the downlink control information into two parts: a first part containing basic scheduling information (resource allocation, MCS, redundancy version) that can be decoded with low complexity, and a second part containing additional information (precoding matrix indicator, hopping parameters) that is either omitted or transmitted separately. This segmentation allows MTC devices to receive essential communication functionality while avoiding the power consumption and cost associated with processing all standard LTE protocol elements.
2Adaptability or versatility
If full LTE protocol support is implemented, then comprehensive communication capabilities are achieved, but device cost and complexity increase
Solution Approach 1:
The patent extracts and removes unnecessary control information elements from the downlink control information transmitted to MTC devices. Specifically, it omits the precoding matrix indicator (PMI) and channel quality indicator (CQI) feedback requirements, and removes hopping parameters for frequency hopping. This extraction reduces device complexity and cost while maintaining essential communication capabilities through the remaining control information.
3Reliability
If repetition across multiple subframes is used, then coverage is enhanced, but transmission time increases
Solution Approach 1:
The patent employs periodic repetition of the downlink control information across multiple subframes to enhance coverage for MTC devices. The same control information (or essential portions of it) is transmitted repeatedly in a periodic manner, allowing devices in poor coverage conditions to accumulate sufficient signal energy over multiple transmission instances. This periodic action achieves coverage enhancement while minimizing time loss by using efficient repetition strategies rather than extended transmission sequences.
Data Source
AI summary
A communication device receives a repetition index, a set indicator, and a downlink transmission. The downlink transmission spans a plurality of subframes. The communication device uses the repetition index as an index into one of a plurality of sets of subframe values specified by the set indicator to determine the number of subframes spanned by the downlink transmission, and decodes the downlink transmission according to the determined number of subframes.