Adaptive Demodulation Reference Signal Construction for MIMO Retransmissions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face challenges in efficiently constructing demodulation reference signals (DM-RS) for retransmissions in multiple-input multiple-output (MIMO) systems, particularly in adapting transmission ranks and constructing DM-RS based on downlink transmissions, which affects the reliability and throughput of data transmission.
Innovation Solution
The method involves transmitting first and second codewords according to an initial transmission rank, receiving downlink transmissions with physical hybrid automatic retransmission request indicator channels, constructing DM-RS based on this information, and retransmitting the codewords with the DM-RS according to a retransmission rank, allowing for adaptive or non-adaptive retransmission strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If DM-RS is constructed based on initial transmission rank, then construction process is simple, but retransmission performance deteriorates when rank changes
Solution Approach 1:
The patent applies dynamics by making the DM-RS construction adaptive to the retransmission rank rather than fixed to the initial transmission rank. The system dynamically adjusts the DM-RS construction parameters based on the actual retransmission rank, allowing the reference signal to effectively support channel estimation regardless of rank changes between initial transmission and retransmission.
2Productivity
If adaptive retransmission strategy is implemented, then throughput is improved, but system complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the DM-RS construction parameters based on the retransmission rank. Instead of implementing complex adaptive retransmission strategies throughout the entire system, the invention focuses on changing the DM-RS construction parameters (such as orthogonal cover code selection) according to the rank indication, achieving throughput improvement through targeted parameter adaptation.
3Measurement precision
If DM-RS is constructed using downlink transmission information, then channel estimation accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by having the terminal store and recall downlink transmission information (such as precoding matrix indicators and rank indicators) that were received in previous transmissions. This pre-stored information is then utilized during retransmission to construct the DM-RS, improving channel estimation accuracy without requiring complex real-time processing during the retransmission itself.
Data Source
AI summary
Provided is a method for wireless communication which includes transmitting codewords according to an initial transmission rank, receiving downlink transmissions indicating at least one of the codewords to be retransmitted, constructing a demodulation reference signal (DM-RS) to be sent with the at least one codeword to be retransmitted, and retransmitting the at least one codeword with the DM-RS according to a retransmission rank. The downlink transmissions may include one or more physical hybrid automatic retransmission request indicator channels and the DM-RS may be constructed based at least in part on information in the downlink transmissions.