MTC Random Access Preamble Repetition and Power Control
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Solution Overview
Problem
Machine-type communication (MTC) terminals face challenges in inferior radio propagation environments, requiring repeated transmission of control information and data across multiple subframes, while typical terminals do not need to repeat random access preambles, leading to inadequate transmission power determination for MTC terminals.
Innovation Solution
A method and device for determining the repetition level and transmission power of random access preambles for MTC terminals, involving parameters like downlink path loss, maximum transmission power, and specific signaling to improve coverage and reception performance by adjusting transmission power and repetition levels based on feedback and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random access preamble is repeatedly transmitted through multiple subframes for MTC terminals, then coverage and reception performance are improved, but transmission power determination becomes inadequate and device complexity increases
Solution Approach 1:
The patent introduces a repetition level parameter that can be determined through multiple methods: receiving signaling from the base station, calculating based on downlink path loss, or determining based on maximum transmission power. This parameter change enables the system to adapt transmission characteristics to propagation conditions, resolving the contradiction between improved reliability and reduced complexity.
Solution Approach 2:
The patent makes the random access preamble transmission dynamic by allowing the repetition level and transmission power to be adjusted based on determined parameters. The terminal can adaptively change transmission characteristics according to channel conditions and network requirements, achieving both improved coverage and manageable complexity through conditional adaptation.
2Reliability
If transmission power of random access preamble is increased for MTC terminals, then coverage is improved, but energy consumption increases
Solution Approach 1:
The patent determines transmission power based on multiple parameters including downlink path loss, maximum transmission power, and repetition level. By calculating transmission power as a function of these parameters rather than using fixed high power, the system achieves improved coverage while optimizing energy consumption according to actual channel conditions.
Solution Approach 2:
The patent applies partial action by transmitting the random access preamble a specific number of times determined by the repetition level rather than continuously or excessively. This controlled repetition provides sufficient coverage improvement while avoiding excessive energy consumption that would result from unlimited retransmissions.
3Reliability
If random access preamble repetition level is increased, then reception performance is improved, but transmission time increases
Solution Approach 1:
The patent determines the repetition level as a specific parameter that balances reception performance and transmission time. By receiving signaling from the base station or calculating based on path loss, the terminal can determine an optimal repetition level that achieves sufficient reception performance without unnecessary time extension from excessive repetitions.
Data Source
AI summary
Provided are a method and a device for setting a repetition level of a random access preamble and determining transmission power for each random access preamble, when a random access preamble for an MTC terminal is repetitively transmitted and received to increase the transmission and reception performance of a random access preamble for a coverage-restricted MTC terminal. Provided are also a method and a device for controlling transmission power for a random access preamble when a terminal, located in improved coverage compared to the coverage for a general terminal, repetitively transmits the random access preamble. When the terminal repetitively transmits a PRACH through a plurality of uplink subframes, the terminal can determine the repetition number of transmitting the PRACH, determine transmission power for the PRACH based on the determined repetition number, and transmit the PRACH at the transmission power determined for the PRACH.