DFT-s-OFDM Frequency Multiplexing for Low-Overhead Reference Signals
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Solution Overview
Problem
Existing wireless communication technologies face challenges in efficiently multiplexing data signals and reference signals, particularly in high-frequency bands, leading to increased reference signal overhead, interference, and inefficient resource usage.
Innovation Solution
Implementing frequency domain multiplexing of data and reference signals within a symbol of a DFT-s-OFDM waveform communication, optimizing reference signal density to balance waveform peak-to-average-power ratio and estimation performance, thereby reducing overhead and improving channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference signal density is increased to improve channel estimation accuracy, then measurement precision improves, but resource overhead increases and spectral efficiency deteriorates
Solution Approach 1:
The patent segments reference signals into different types (demodulation reference signals, sounding reference signals, channel state information reference signals) with different densities and purposes. This allows selective placement of reference signals in specific time-frequency resources rather than uniform distribution, reducing overall overhead while maintaining estimation accuracy where needed.
Solution Approach 2:
The patent applies different reference signal densities to different spatial, temporal, and frequency locations based on channel conditions. In regions with poor channel conditions or high mobility, higher reference signal density is applied to improve estimation accuracy, while in stable channels, density is reduced to minimize overhead.
2Productivity
If reference signal overhead is reduced to improve spectral efficiency, then productivity improves, but channel estimation robustness deteriorates
Solution Approach 1:
The patent implements dynamic reference signal density adjustment based on channel conditions, user mobility, and service requirements. The network can adaptively configure reference signal patterns in real-time, increasing density when channel conditions deteriorate and reducing density when conditions improve, thus maintaining robustness while optimizing spectral efficiency.
Solution Approach 2:
The patent changes multiple parameters including reference signal density, bandwidth occupation, time-domain positioning, and frequency-domain distribution to optimize the balance between overhead and estimation robustness. Different parameter configurations are applied based on service types (e.g., enhanced mobile broadband, machine type communication, ultra-reliable low-latency communication).
3Loss of time
If frequency domain multiplexing is implemented to reduce overhead, then loss of time is reduced, but signal interference increases
Solution Approach 1:
The patent uses orthogonal frequency division multiplexing techniques and orthogonal cover codes as intermediaries to separate reference signals from data signals in the frequency domain. This allows simultaneous transmission without direct interference, as the orthogonal structures ensure that reference signals can be cleanly extracted from multiplexed transmissions.
Solution Approach 2:
The patent moves reference signal placement from time-domain separation to frequency-domain multiplexing, utilizing the frequency dimension to coexist with data signals. This dimensional transition allows reference signals to be embedded within data transmissions without requiring separate time slots, reducing latency while managing interference through frequency-selective placement.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a transmitting device may generate a frequency-domain-multiplexed signal by performing frequency domain multiplexing of a data signal and a reference signal within a symbol of a discrete Fourier transform spread orthogonal frequency domain multiplexing waveform communication, the reference signal being one of a demodulation reference signal, a sounding reference signal, or a channel state information reference signal. The transmitting device may transmit, to a receiving device, the frequency-domain-multiplexed signal. Numerous other aspects are described.