PRACH Coverage Extension Level for MTC Devices
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Solution Overview
Problem
Current mobile broadband networks are not optimized for Machine-Type Communication (MTC) specific requirements, leading to inadequate coverage for MTC devices, especially those installed in basements, which experience significant radio interface penetration losses, necessitating specialized coverage enhancement mechanisms.
Innovation Solution
The use of Physical Random Access Channel (PRACH) transmission to indicate coverage extension levels for MTC devices, allowing them to repeat preamble sequences in the time domain to accumulate energy and improve communication reliability, with variable repetition levels to match specific coverage needs, reducing unnecessary power consumption and resource waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MTC devices repeat preamble sequences multiple times to accumulate energy for coverage extension, then communication reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of repetition levels based on coverage enhancement needs. Devices can select from multiple configured repetition levels (e.g., 2, 4, 8, 16 repetitions) matched to different path loss conditions, allowing the system to optimize between reliability and power consumption by using only the necessary repetition count for each device's specific coverage requirements
Solution Approach 2:
The system changes the parameter of repetition level dynamically based on coverage enhancement requirements. By configuring multiple repetition levels and allowing devices to select appropriate levels based on their channel conditions, the system achieves optimal balance between communication reliability and power consumption without fixed over-provisioning
2Length of stationary object
If MTC devices use coverage enhancement mechanisms with repeated transmissions, then coverage extension is achieved, but spectral efficiency deteriorates
Solution Approach 1:
The patent segments PRACH resources into multiple non-overlapping subsets, with each subset dedicated to specific repetition levels. This segmentation allows the system to allocate resources efficiently - devices using coverage enhancement with repetitions are isolated to specific resource subsets, preventing waste of overall spectral resources while still providing necessary coverage extension to devices that need it
3Object-affected harmful factors
If MTC devices transmit with higher power for coverage extension, then penetration loss is compensated, but resource waste increases
Solution Approach 1:
The system provides multiple configured repetition levels (2, 4, 8, 16) that correspond to different coverage enhancement needs. Devices select the appropriate repetition level based on their measured path loss, transmitting with higher effective energy only when necessary. This prevents resource waste by avoiding excessive repetitions for devices with good coverage while providing sufficient enhancement for devices in poor coverage conditions
Data Source
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AI summary
Generally discussed herein are systems, apparatuses, and methods that can provide a coverage enhancement to a coverage limited device. According to an example a method can include determining a received signal strength of a reference signal transmitted from a base station, determining a coverage enhancement based on the determined signal strength, or transmitting a signature sequence of a plurality of signature sequences a first repeated number of times corresponding to the determined coverage enhancement.