MTC UE PRACH Resource Selection for Random Access
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Solution Overview
Problem
In LTE networks, MTC UE faces challenges in selecting an appropriate PRACH resource for random access when triggered by the network side, especially in scenarios where the UE's current CE level is not among those indicated by the network, leading to difficulties in initiating successful random access procedures.
Innovation Solution
The MTC UE receives indication information from the network side regarding available CE levels and corresponding PRACH resources, allowing it to select an appropriate PRACH resource based on its own CE level and the network-indicated levels, and transition to a higher CE level if initial attempts fail, thereby initiating a contention-free or contention random access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the network side indicates specific CE levels for PRACH resources, then the random access procedure can be optimized for indicated levels, but MTC UE with non-indicated CE levels cannot select appropriate PRACH resources
Solution Approach 1:
The patent makes the PRACH resource selection dynamic by introducing a mapping relationship between CE levels and PRACH resources. When the network indicates specific CE levels, the UE dynamically selects PRACH resources based on its current CE level according to pre-configured or network-indicated mapping rules, allowing adaptability to different CE levels while maintaining optimization for indicated levels.
Solution Approach 2:
The patent changes the parameter mapping between CE levels and PRACH resources. By configuring mapping relationships that associate multiple CE levels with appropriate PRACH resources, the system allows UEs at non-indicated CE levels to find suitable PRACH resources through parameter mapping, thus resolving the contradiction between optimization and adaptability.
2Area of stationary object
If MTC UE transitions to higher CE level for random access, then coverage is improved, but access delay and power consumption increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring mapping relationships between CE levels and PRACH resources before random access occurs. This allows the UE to quickly determine the appropriate PRACH resource based on its current CE level without needing to transition to higher CE levels, thus maintaining coverage while reducing access delay and power consumption.
Solution Approach 2:
The patent introduces a mapping relationship as an intermediary between CE levels and PRACH resources. This intermediary enables UEs to access the network using PRACH resources appropriate for their current CE level without requiring physical layer transitions to higher CE levels, thereby achieving coverage extension while minimizing time and energy costs.
3Reliability
If repeated transmission is applied to enhance coverage, then signal reliability improves, but system complexity and resource overhead increase
Solution Approach 1:
The patent segments the random access procedure by introducing CE level-based PRACH resource selection. Instead of applying repeated transmission for all UEs, the system divides UEs into different CE levels and assigns appropriate PRACH resources, achieving reliable signal reception for each segment without requiring universal repeated transmission, thus reducing overall system complexity.
Data Source
AI summary
The present invention provides an MTC UE random access method and device. The method comprises: receiving indication information sent by a network side, the indication information being used for indicating at least one coverage enhancement level (CE LEVEL) and a physical random access channel (PRACH) resource corresponding thereto; selecting one CE LEVEL from a CE LEVEL of an MTC UE and the CE LEVEL indicated by the network side, and determining a PRACH resource corresponding to the CE LEVEL; and carrying out random access on the PRACH resource corresponding to the selected CE LEVEL. The present invention provides a mechanism of how to select a PRACH resource when a network side triggers an MTC UE to initiate a contention-free random access (CFRA) process.