Waveform Multiplexing in Millimeter Wave Bands
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Solution Overview
Problem
Wireless communication systems operating at high millimeter wave (mmWave) bands face challenges due to increased radio frequency (RF) phase noise and propagation loss, which require higher transmission power, but power amplifiers have low efficiency at high frequencies, and existing waveforms like OFDM have high peak-to-average power ratio (PAPR), leading to inefficiencies in data throughput.
Innovation Solution
The use of single-carrier (SC) waveforms with lower PAPR, such as cyclic prefix (CP)-based and guard interval (GI)-based SC waveforms, is proposed to mitigate inter-symbol interference (ISI) by strategically configuring waveform signals, including blank periods and reference signal sequences, to enable efficient multiplexing across different frequency bands and beam directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM waveforms are used to achieve high data throughput, then spectral efficiency is improved, but peak-to-average power ratio increases leading to power amplifier inefficiency
Solution Approach 1:
The patent changes the waveform parameter from OFDM to single-carrier waveforms (CP-based or GI-based), which fundamentally alters the PAPR characteristic from high to low, thereby improving power amplifier efficiency while maintaining acceptable data throughput
2Length of stationary object
If higher transmission power is used to overcome propagation loss in mmWave bands, then coverage range is improved, but power amplifier efficiency deteriorates due to low efficiency at high frequencies
Solution Approach 1:
The patent changes the waveform type to single-carrier waveforms with lower PAPR, which reduces the peak power requirements and improves power amplifier efficiency, thereby reducing energy loss while maintaining coverage range
3Use of energy by moving object
If single-carrier waveforms are used to reduce PAPR and improve power efficiency, then power amplifier efficiency is improved, but spectral efficiency may deteriorate compared to OFDM
Solution Approach 1:
The patent introduces dynamic waveform selection between CP-based and GI-based single-carrier waveforms, allowing the system to adaptively choose the most appropriate waveform type based on channel conditions and service requirements, thereby optimizing spectral efficiency while maintaining power amplifier efficiency
4Reliability
If guard interval-based waveforms are used to mitigate inter-symbol interference, then reliability is improved, but overhead increases reducing spectral efficiency
Solution Approach 1:
The patent enables dynamic selection between CP-based and GI-based waveforms, allowing the system to choose GI-based waveforms when ISI mitigation is critical (improving reliability) while switching to CP-based waveforms when spectral efficiency is prioritized, thus dynamically balancing reliability and spectral efficiency
Data Source
AI summary
Wireless communications systems and methods related to multiplexing different waveforms in wireless networks are provided. A first wireless communication device identifies a configuration for communicating a first guard interval (GI)-based waveform signal after at least one of a second GI-based waveform signal or a cyclic prefix (CP)-based waveform signal. The first wireless communication device communicates, with a second wireless communication device, the first GI-based waveform signal including a plurality of first symbols, wherein a beginning symbol of the plurality of first symbols include repetitions of a reference signal sequence based on the configuration.