User Device Signal Repetition for Weak Coverage Detection
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Solution Overview
Problem
Fourth generation mobile communication systems face challenges in providing reliable data transmission and reception to devices located in areas with attenuated signal channels, such as smart meters in basements or near network borders, where existing solutions like reduced coding rates and modulation schemes are limited due to device capabilities and compatibility constraints.
Innovation Solution
Implementing signal repetition using Orthogonal Frequency Division Multiplexing (OFDM) subcarriers, where infrastructure equipment transmits repeated signals across a second bandwidth within the first bandwidth, allowing user devices to combine and detect payload data more accurately, reducing memory requirements and improving signal strength without altering coding rates or modulation orders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signal repetition is implemented across the full first bandwidth, then detection reliability is improved, but memory requirements and processing complexity increase
Solution Approach 1:
The patent segments the full first bandwidth into multiple second bandwidths, each containing a subset of OFDM subcarriers. The infrastructure equipment transmits repeated signals in different second bandwidths across multiple time periods. The user device only needs to store and process signals within these segmented second bandwidths rather than the entire first bandwidth, reducing memory requirements while maintaining detection reliability through multiple repetitions.
2Reliability
If decreased coding rates and reduced order modulations are used, then detection reliability is improved, but device capability requirements and system compatibility are constrained
Solution Approach 1:
Instead of changing coding rates or modulation orders, the patent changes the transmission parameter of bandwidth utilization. By transmitting repeated signals across multiple second bandwidths within the first bandwidth, the system achieves improved detection reliability through parameter diversity in the frequency domain without modifying coding or modulation parameters, thus maintaining compatibility with existing device capabilities.
3Area of stationary object
If signal repetition is implemented, then coverage area is extended, but transmission time and resource utilization increase
Solution Approach 1:
The patent implements periodic transmission of repeated signals across multiple time periods. The infrastructure equipment transmits the same payload data instance in different second bandwidths during different time periods. This periodic repetition allows user devices in coverage extension areas to accumulate sufficient signal quality over time while the system maintains efficient resource utilization by reusing the same time-frequency resources pattern.
Data Source
AI summary
A user device to transmit and receive data to and from an infrastructure equipment via a wireless access interface using a plurality of Orthogonal Frequency Division Multiplexing (OFDM) subcarriers extending across at least a first bandwidth. The infrastructure equipment transmits repeatedly signals representing a same instance of user device payload data in a second bandwidth, the second bandwidth being less than and within the first bandwidth and including a subset of the OFDM subcarriers. The user device is configured to receive one or more of the signals repeatedly transmitted across the second bandwidth and to store in a memory signals representing the repeatedly transmitted signals received across the second bandwidth. The user device is also configured to combine the stored signals and to detect the user device payload data from the combined signals, the user device having been provided with an indication of the second bandwidth.