MTC SRS Transmission via Frequency-Hopped PUSCH Subbands
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Solution Overview
Problem
In wireless communication systems supporting Machine Type Communication (MTC), existing methods face challenges in reliably transmitting Sounding Reference Signals (SRS) and efficiently managing uplink data transmission, particularly when the SRS and data transmission subbands are not identical, leading to potential data throughput loss due to frequency retuning.
Innovation Solution
The method involves an MTC User Equipment (UE) receiving higher-layer signals to configure and transmit SRS in a frequency-hopped subband allocated for Physical Uplink Shared Channel (PUSCH), with the SRS being transmitted sequentially and repeatedly, allowing for improved channel estimation and reduced data throughput loss by aligning SRS and PUSCH subbands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SRS is transmitted in a different subband from uplink data, then frequency retuning is required causing data throughput loss, but if SRS and data use the same subband then channel estimation reliability improves
Solution Approach 1:
The patent applies preliminary action by transmitting the SRS signal before the uplink data transmission in advance of time T0. This allows the base station to perform channel estimation using the pre-transmitted SRS signal, so that when the data transmission occurs, the channel state information is already available, eliminating the need for frequency retuning and preventing data throughput loss while maintaining channel estimation reliability
Solution Approach 2:
The patent implements dynamics by allowing the MTC UE to dynamically select between different subbands for SRS transmission based on the allocated PUSCH subband. The UE can transmit SRS in the same subband as the PUSCH or in a different subband, with the base station adjusting the timing accordingly. This dynamic flexibility resolves the contradiction by enabling adaptive resource allocation that prioritizes channel estimation reliability when needed while maintaining data throughput efficiency
2Measurement precision
If SRS transmission subband is aligned with PUSCH subband, then channel estimation is improved, but frequency retuning is avoided only when subbands are identical
Solution Approach 1:
The patent uses preliminary action to transmit SRS before PUSCH transmission, allowing the base station to obtain channel state information in advance. This eliminates the need for the SRS and PUSCH to be in the same subband, reducing the complexity of subband coordination while maintaining accurate channel estimation through the提前 obtained signal
Solution Approach 2:
The patent introduces time as an intermediary dimension to resolve the subband alignment issue. Instead of requiring SRS and PUSCH to occupy the same frequency subband simultaneously, the system uses temporal separation where SRS is transmitted in a previous time slot, allowing flexible subband selection while maintaining estimation accuracy through the time-shifted signal
Data Source
AI summary
The present invention provides methods for controlling transmission of a sounding reference signal (SRS) in a wireless access system supporting machine type communication (MTC) and devices for supporting same. A method for controlling transmission of an SRS by an MTC terminal in a wireless access system supporting MTC, according to an embodiment of the present invention, can comprise the steps of: receiving an upper layer signal comprising information about an SRS which is to be repeatedly transmitted; configuring the SRS on the basis of the information about the SRS; and transmitting the SRS by means of a subband to which a physical uplink shared channel (PUSCH) is allocated and which is being frequency hopped. The subband comprises six physical resource blocks (PRB), and the SRS can be sequentially transmitted to the subband being frequency hopped.