RAR Window Configuration for MTC Coverage Enhancement
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Solution Overview
Problem
The LTE network faces challenges in supporting Machine Type Communication (MTC) devices due to high penetration loss in environments like basements or buildings with metal walls, leading to low data transmission rates and limited mobility, necessitating enhanced coverage and low power consumption without increasing complexity or costs.
Innovation Solution
The solution involves configuring Random Access Response (RAR) windows with different coverage enhancement levels, allowing for varying repetition windows and subframes to improve signal strength and reliability for MTC UEs, enabling them to operate effectively in challenging environments by adjusting the RAR window size and back-off indicators based on coverage enhancement levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LTE network configuration is used, then system complexity and device costs are kept low, but MTC devices experience high penetration loss and low data transmission rates in challenging environments
Solution Approach 1:
The patent applies local quality by configuring different RAR window parameters (ra-ResponseWindowSize) specifically for MTC devices based on their coverage enhancement levels, rather than using uniform settings for all devices. This allows tailored optimization for MTC devices in challenging environments while maintaining standard configurations for other devices, thus improving reliability without universally increasing system complexity
Solution Approach 2:
The patent changes key parameters including RAR window size, subframe configurations, and back-off indicators specifically for MTC devices with coverage enhancement. By adjusting these parameters based on coverage enhancement levels (CE levels), the system improves signal reception reliability for MTC devices while managing complexity through targeted parameter modification rather than system-wide changes
2Reliability
If RAR window size is increased to improve coverage, then MTC devices in poor coverage areas can receive signals better, but delay increases and system responsiveness deteriorates
Solution Approach 1:
The patent implements dynamic RAR window configuration where the ra-ResponseWindowSize and related parameters are adjusted based on coverage enhancement levels. MTC devices at different CE levels receive appropriately sized RAR windows - larger for devices in poor coverage to ensure reception, and smaller for devices in better coverage to minimize delay. This dynamic adaptation resolves the contradiction between coverage enhancement and access delay
Solution Approach 2:
The patent segments the RAR window configuration into different settings based on coverage enhancement levels. Instead of using a single uniform RAR window size for all devices, the system divides configurations into multiple levels (e.g., CE0, CE1, CE2, CE3) with progressively larger windows, allowing each segment to be optimized for its specific coverage conditions, thus balancing coverage enhancement with acceptable delay
3Reliability
If repetitive transmissions are used to enhance signal strength, then received signal quality improves, but power consumption increases
Solution Approach 1:
The patent optimizes the balance between signal strength and power consumption by carefully adjusting parameters such as the number of repetitive transmissions, RAR window size, and back-off indicators based on coverage enhancement levels. By changing these parameters adaptively, the system ensures sufficient signal strength for reliable communication while avoiding excessive repetition that would unnecessarily increase power consumption of mobile MTC devices
Data Source
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AI summary
The present disclosure provides a base station. The base station comprises: a configuration unit configured to configure sizes of Random Access Response (RAR) windows for RARs having different coverage enhancement levels; and a transmission unit configured to transmit a Media Access Control (MAC) Protocol Data Unit (PDU) of an RAR over a repetition window within an RAR window. Also provided are a User Equipment (UE) and associated methods.