Non-Contention Random Access Configuration for MTC Coverage Improvement
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Solution Overview
Problem
Machine Type Communication (MTC) User Equipment (UE) in LTE/LTE-A systems face challenges in achieving reliable non-contention random access, especially in scenarios requiring Coverage Improvement (CI), due to limitations in power enhancement and access quality, leading to suboptimal performance in penetration loss scenarios.
Innovation Solution
The method involves configuring non-contention random access parameters, such as repeated sending levels for random access messages, Random Access Responses (RAR), and Msg3 messages, along with a Coverage Improvement Level (CIL), which are sent through a downlink channel to improve access performance. This includes specific allocation of PRACH preambles and repetition levels to enhance the UE's ability to access the system effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If MTC UE reduces cost by reducing receiving antennae and baseband processing bandwidths, then manufacturing cost decreases, but coverage performance deteriorates
Solution Approach 1:
The patent changes the parameter of random access message repetition level to compensate for the reduced coverage performance of low-cost MTC UEs. By configuring different repetition levels (e.g., 4, 8, 16 times) based on coverage improvement needs, the system enables cost-reduced devices to achieve reliable access in challenging coverage scenarios without requiring additional hardware complexity.
2Power
If MTC UE transmits PRACH preamble at full power, then transmission power is maximized, but access quality for CI UEs still cannot be guaranteed
Solution Approach 1:
The patent applies preliminary action by configuring the repetition level of random access messages before the actual access attempt. The eNB determines and signals the appropriate repetition level to the MTC UE based on its coverage improvement needs, allowing the UE to prepare the correct number of transmissions in advance. This preliminary configuration ensures that CI UEs can achieve reliable access by transmitting the predetermined number of repeated messages rather than relying solely on power increases.
3Reliability
If the system increases repetition levels for random access messages, then access reliability for CI UEs improves, but access time delay increases
Solution Approach 1:
The patent implements dynamics by making the repetition level configurable and adaptable rather than fixed. The eNB can dynamically adjust the repetition level parameter (e.g., 4, 8, or 16 times) based on the specific coverage conditions and UE capabilities. This dynamic configuration allows the system to optimize between reliability and time delay - using higher repetition levels only when necessary for CI UEs while maintaining faster access for normal UEs, thus resolving the contradiction between access reliability and time delay.
Data Source
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AI summary
Methods, nodes, a system, and computer storage mediums for non-contention random access are provided. The method for non-contention random access includes that: a first node sends configuration information of non-contention random access to a second node through a downlink channel; and the second node obtains the configuration information of the non-contention random access, and sends a random access message on a Physical Random Access Channel (PRACH) according to the configuration information.