DMRS Allocation Pattern for Variable Transmission Periods
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Solution Overview
Problem
Future radio communication systems, such as LTE Rel. 14 and 5G, face challenges in demodulating data channels with variable transmission periods due to fixed DMRS allocation patterns in existing LTE systems, leading to inadequate demodulation of data channels with non-standard subframe lengths.
Innovation Solution
The solution involves determining DMRS allocation patterns based on the number of symbols in the transmission period, allowing for scalable and simple DMRS allocation while maintaining accurate channel estimation and low coding rates, by controlling the DMRS pattern in the frequency and time directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed DMRS allocation patterns are used in existing LTE systems, then demodulation is adequate for standard subframes, but demodulation becomes inadequate for data channels with variable transmission periods
Solution Approach 1:
The patent applies dynamics by making the DMRS allocation pattern adaptive rather than fixed. The control section dynamically determines DMRS allocation based on the actual number of symbols in the transmission period, allowing the system to adjust to variable TTI lengths while maintaining reliable demodulation for both standard and non-standard subframes
Solution Approach 2:
The patent changes the allocation parameters of DMRS based on the transmission period characteristics. By modifying the DMRS allocation pattern according to the number of symbols in the data channel transmission, the system maintains adequate demodulation performance across different TTI configurations
2Adaptability or versatility
If DMRS allocation patterns are optimized for variable transmission periods, then future radio communication systems gain adaptability, but existing LTE systems may experience increased complexity
Solution Approach 1:
The patent implements self-service by enabling the terminal to autonomously determine the appropriate DMRS allocation pattern based on the number of symbols in the transmission period. The control section in the terminal automatically adjusts the allocation without requiring complex external control or configuration, reducing overall system complexity while maintaining adaptability
Data Source
AI summary
A terminal is disclosed including a receiver that receives downlink control information indicating a transmission bandwidth allocated to a downlink shared channel within a bandwidth part, and a processor that determines a size of a precoding resource block group (PRG), to which a same precoding is applied, based on the transmission bandwidth or a subset of the transmission bandwidth. In other aspects, a radio communication method for a terminal is also disclosed.