Multi-Antenna Signal Transmission on Separate Subcarriers
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Solution Overview
Problem
In multi-antenna wireless systems, there is a fundamental tradeoff between multiplexing gain and diversity gain, making it difficult to optimize both simultaneously for applications requiring low latency and high reliability.
Innovation Solution
Transmit and receive signals using distinct subcarriers from separate antennas, employing Spatial Multiple Carrier Modulation (SMCM) to achieve spatial and frequency diversity without increasing overall transmission power, utilizing orthogonal subcarriers and varying modulation and encoding schemes across antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial degrees of freedom are employed to increase multiplexing gain in multi-antenna systems, then data transmission capacity is improved, but diversity gain deteriorates
Solution Approach 1:
The patent segments the frequency spectrum into multiple subcarriers and assigns different subsets of subcarriers to different transmit antennas. This segmentation allows the system to achieve both multiplexing gain (by transmitting different data streams on different antennas) and diversity gain (by transmitting redundant data across multiple antennas and subcarriers), resolving the fundamental tradeoff between these two performance metrics.
Solution Approach 2:
The patent introduces a frequency dimension to the spatial multiplexing scheme by using orthogonal subcarriers from an OFDM spectrum. Instead of only exploiting spatial dimensions, the system combines spatial (multiple antennas) and frequency (multiple subcarriers) dimensions, allowing data to be transmitted through multiple paths in both space and frequency, thereby achieving both multiplexing and diversity gains simultaneously.
2Reliability
If spatial degrees of freedom are employed to increase diversity gain in multi-antenna systems, then reliability is improved, but multiplexing gain deteriorates
Solution Approach 1:
The patent segments the frequency spectrum into multiple subcarriers and assigns different subsets of subcarriers to different transmit antennas. This segmentation allows the system to achieve both multiplexing gain (by transmitting different data streams on different antennas) and diversity gain (by transmitting redundant data across multiple antennas and subcarriers), resolving the fundamental tradeoff between these two performance metrics.
Solution Approach 2:
The patent introduces a frequency dimension to the spatial multiplexing scheme by using orthogonal subcarriers from an OFDM spectrum. Instead of only exploiting spatial dimensions, the system combines spatial (multiple antennas) and frequency (multiple subcarriers) dimensions, allowing data to be transmitted through multiple paths in both space and frequency, thereby achieving both multiplexing and diversity gains simultaneously.
3Productivity
If multiple antennas transmit signals using the same subcarriers, then spectral efficiency is improved, but processing complexity increases
Solution Approach 1:
The patent segments the frequency spectrum into multiple subcarriers and assigns different subsets of subcarriers to different transmit antennas. This segmentation creates orthogonal signal paths that are easier to process at the receiver, reducing the complexity of signal separation and processing while maintaining high spectral efficiency through efficient use of available frequency resources.
Data Source
AI summary
In one example aspect, a method of transmitting signals is provided, the method comprising transmitting signals using one or more first subcarriers only from a first antenna, wherein the signals transmitted from the first antenna comprise first signals based on data, and transmitting signals using one or more second subcarriers different from the one or more first subcarriers only from a second antenna, wherein the signals transmitted from the second antenna comprise second signals based on the data.