MTC Device Random Access Preamble Repetition for Coverage Enhancement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MTC devices in coverage extension regions face difficulties in receiving and transmitting random access channels due to poor signal reception, leading to challenges in efficient communication with the base station.
Innovation Solution
The MTC device employs a method of repeatedly transmitting random access preambles according to a specific repetition level and adjusts this level or uses power ramping when initial transmissions are not properly received, ensuring effective communication by reconfiguring the repetition level based on reception feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the BS transmits downlink channel to MTC device in coverage extension region using normal transmission method, then the transmission method is simple, but the MTC device has difficulty in receiving the channel
Solution Approach 1:
The base station transmits the downlink channel repeatedly multiple times to MTC devices in coverage extension regions. This periodic transmission allows devices with poor reception to accumulate signal energy and successfully decode the channel, resolving the contradiction between reception reliability and transmission complexity by using simple repeated transmissions rather than complex adaptive modulation.
Solution Approach 2:
The system changes transmission parameters including the number of repetitions and transmission power based on device location and channel conditions. For coverage extension regions, higher repetition counts and power levels are applied, while normal regions use standard parameters, thus achieving reliable reception without unnecessarily increasing complexity for all devices.
2Reliability
If the MTC device in coverage extension region transmits uplink channel using usual method, then the transmission method is simple, but the BS has difficulty in receiving the uplink channel
Solution Approach 1:
MTC devices in coverage extension regions transmit uplink channels including PRACH repeatedly multiple times. This periodic transmission ensures that the base station can successfully receive and decode the signal despite poor uplink channel conditions, resolving the contradiction by using simple repeated transmissions rather than complex power control algorithms.
Solution Approach 2:
The system configures different transmission parameters for devices in coverage extension regions versus normal regions. Devices in extension regions use higher repetition counts and adjusted power levels for uplink transmissions, enabling reliable base station reception without requiring complex adaptive transmission mechanisms.
3Reliability
If the BS receives PRACH from MTC device in coverage extension region using normal reception method, then the reception method is simple, but the BS has difficulty in receiving the PRACH
Solution Approach 1:
The base station receives and processes repeated PRACH transmissions from MTC devices in coverage extension regions. By accumulating multiple repeated transmissions, the base station can successfully decode the random access preamble even with poor signal conditions, resolving the contradiction through simple repeated reception rather than complex signal processing.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A disclosure of the present specification provides a method for performing a random access procedure for coverage enhancement. The method may comprise the steps of: transmitting a random access preamble repetitively to a certain cell on the basis of a predetermined repetition level; when a random access response has not received within a random access response window, reconfiguring the repetition level; and retransmitting the random access preamble repetitively on the basis of the reconfigured repetition level.