Wireless Data Stream Multiplexing with Interference Alignment
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Solution Overview
Problem
In D2D communication systems, when a receiving end is configured with a limited number of antennas, it cannot decode received signals due to interference, leading to incomplete data stream recovery.
Innovation Solution
The method involves aligning interference from a second data stream with a first data stream at the receiving end based on the number of antennas configured, allowing the first receiving end to decode the sum of aligned data streams, and the second receiving end to further decode the aligned data streams using the decoded results from the first receiving end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a receiving end is configured with a limited number of antennas, then device complexity is reduced, but the receiving end cannot decode received signals due to interference
Solution Approach 1:
The patent applies interference alignment to convert harmful interference into useful information. By designing precoding vectors such that interference from other data streams aligns with the desired signal in a lower-dimensional subspace, the receiving end can decode the aligned combination of signals despite having fewer antennas than the total number of transmitted streams. This transforms the harmful interference that normally prevents decoding into a decodable signal structure.
Solution Approach 2:
The patent changes the parameter of signal structure by aligning interference in the spatial domain through precoding vector design. Instead of treating interference as random noise, the system deliberately structures the interference to occupy the same spatial subspace as the desired signal, creating a solvable system of equations that can be decoded with fewer antennas.
2Productivity
If multiple data streams are transmitted simultaneously, then system capacity increases, but interference prevents successful decoding at the receiving end
Solution Approach 1:
The patent enables multiple data streams to be transmitted simultaneously by converting the interference they create into a structured, decodable form. Through interference alignment, the combined signal at the receiver contains aligned interference that can be mathematically separated from the desired signal, allowing successful decoding of multiple streams without requiring additional antennas for each stream.
Solution Approach 2:
The patent resolves the decoding problem by operating in the spatial dimension through precoding vector design. By aligning interference in the spatial subspace, the system effectively reduces the dimensionality of the interference problem, allowing the receiver to decode multiple streams using fewer antennas than the total number of streams transmitted.
3Reliability
If interference alignment is implemented, then decoded data streams can be obtained with limited antennas, but calculation complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and designing precoding vectors at the transmitting end that inherently align interference with desired signals. This preliminary design of the transmission structure eliminates the need for complex real-time interference cancellation calculations at the receiver, shifting the computational burden to the transmitter where it can be handled more efficiently.
Data Source
AI summary
The present invention relates to wireless communications. Disclosed are a method and a system for transmitting a data stream, aiming at increasing system capacity. The method includes: transmitting, by a first sending end, a coded first data stream to a first receiving end, and transmitting, by a second sending end, a coded second data stream to a second receiving end on time-frequency resources occupied by transmission of the first data stream by the first sending end, wherein when the second sending end codes the second data stream, interference of at least one data stream in the second data stream to the first receiving end is correspondingly aligned with at least one data stream in the first data stream according to number of antenna(s) configured for the first receiving end; decoding, by the first receiving end, a first received signal received to obtain a first decoded result, and transmitting at least one decoded result in the first decoded result to the second receiving end, wherein the first decoded result at least comprises sum data stream(s) of the above-mentioned correspondingly aligned data streams; and decoding, by the second receiving end, a second received signal received, by using the at least one decoded result in the first decoded result to obtain a second decoded result, wherein the second decoded result at least comprises the above-mentioned correspondingly aligned data streams. The present invention is applicable to a scenario where wireless resources are multiplexed in a communication system.