MTC UE Random Access Response Reception via Multi-Dimensional RA-RNTI
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Solution Overview
Problem
Machine-Type Communication (MTC) User Equipments (UEs) face challenges in achieving a proper random access procedure due to limited radio resources and increased collision likelihood when transmitting and receiving random access responses, leading to errors and failed initial access procedures.
Innovation Solution
The method involves MTC UEs repeatedly transmitting random access preambles through a Physical Random Access Channel (PRACH) and determining a Random Access Radio Network Temporary Identifier (RA-RNTI) using time and frequency index information, allowing for proper reception of random access responses within a designated window, while base stations receive and process these preambles to transmit accurate responses using the same RA-RNTI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MTC UE repeatedly transmits random access preambles to improve reception reliability in poor propagation environments, then the coverage and reliability are improved, but the likelihood of collision between random access responses increases and radio resources are restricted
Solution Approach 1:
The patent segments the random access response identification by introducing multiple parameters (first time index information, frequency index information, second time index information) to divide the RA-RNTI space. This segmentation allows multiple MTC UEs to have distinct RA-RNTIs even when transmitting in overlapping time-frequency resources, thereby reducing collision between random access responses while maintaining repeated transmission for reliability.
2Device complexity
If MTC UE is restricted to use only some frequency resources or some time resources, then the resource management is simplified, but the ability to achieve proper random access procedure is reduced
Solution Approach 1:
The patent extends the RA-RNTI determination from traditional single-dimension (time or frequency) to multi-dimension by incorporating first time index information, frequency index information, and second time index information. This dimensional expansion allows MTC UEs to be properly identified even when restricted to specific time-frequency resources, maintaining random access reliability while preserving resource management simplicity.
3Productivity
If the base station processes a very limited number of random access responses due to repeated transmissions, then the processing load is reduced, but the number of MTC UEs that can successfully access is limited
Solution Approach 1:
The patent changes the parameters used for RA-RNTI determination by incorporating multiple index information elements (first time index, frequency index, second time index). This parameter expansion increases the RA-RNTI space, allowing the base station to process responses from multiple MTC UEs simultaneously with reduced collision, thereby improving both processing capacity utilization and access success rate.
Data Source
AI summary
The present disclosure relates to a downlink data transmission/reception technique for supporting a low-complexity UE category/type for a MTC operation. A method may be provided for an MTC UE to receive a random access response. The method may include: repeatedly transmitting a random access preamble to a base station through a Physical Random Access Channel (PRACH) of at least one subframe; determining a Random Access Radio Network Temporary Identifier (RA-RNTI) using first time index information, frequency index information, and second time index information on the PRACH; and receiving a random access response to the random access preamble using the RA-RNTI within a random access response window.