MTC Uplink Channel and DMRS Transmission in Sub-PRB Resources
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Solution Overview
Problem
Current mobile communication systems, particularly in 3GPP LTE, lack efficient methods for machine type communication (MTC) devices to transmit uplink channels and demodulation reference signals (DMRS) using frequency resources smaller than a physical resource block (PRB), leading to suboptimal resource allocation and demodulation challenges.
Innovation Solution
A method for MTC devices to determine and transmit uplink channels and DMRS within a frequency resource area equal to or smaller than a PRB, involving the generation of DMRS sequences and their mapping onto specific subcarriers, with resource allocation indicated by DCI, allowing for flexible subcarrier usage and efficient transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MTC devices use frequency resources smaller than one PRB for uplink transmission, then resource utilization efficiency is improved and cost is reduced, but there is no existing method to allocate and demodulate such sub-PRB resources effectively
Solution Approach 1:
The patent segments the PRB into smaller sub-PRB units (e.g., 6 subcarriers instead of 12) to enable finer-grained resource allocation. This segmentation allows MTC devices with small data traffic to use only the necessary frequency resources, improving resource utilization efficiency while providing a structured approach to sub-PRB allocation and demodulation.
2Quantity of substance
If MTC devices transmit using limited subband resources, then cost per unit is reduced, but the system lacks methods to handle DMRS transmission within such limited resources
Solution Approach 1:
The patent applies local quality by configuring DMRS transmission specifically adapted to sub-PRB resources. Instead of using standard PRB-based DMRS configurations, the system locally adapts the DMRS sequence length, mapping position, and resource allocation to match the reduced sub-PRB bandwidth, enabling effective demodulation within limited frequency resources.
3Productivity
If uplink resource size is reduced to one PRB or less, then resource allocation efficiency is improved, but existing systems lack methods to demodulate channels with reduced DMRS resources
Solution Approach 1:
The patent changes key parameters of the DMRS configuration to suit sub-PRB transmission. This includes adjusting the DMRS sequence length to match the reduced number of subcarriers, modifying the mapping position of DMRS within the sub-PRB, and adapting the resource allocation indicators in DCI to reflect sub-PRB granularity. These parameter changes enable reliable demodulation while maintaining improved resource allocation efficiency.
Data Source
AI summary
A disclosure of the present specification provides a method for transmitting an uplink channel and a demodulation reference signal (DMRS) by a machine type communication (MTC) device. The method may comprise the steps of: determining a frequency resource area for transmitting an uplink channel so as to have a size equal to or smaller than the size of a physical resource block (PRB) including 12 subcarriers; generating a DMRS sequence for some sub-carriers among the 12 subcarriers when the frequency resource area for transmitting the uplink channel is determined to have a size smaller than the size of the PRB including the 12 subcarriers; and transmitting the uplink channel and the DMRS on the some subcarriers in the PRB.