Antenna Diversity Scheme Using Orthogonal Spreading Matrices
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Solution Overview
Problem
Existing multiple antennas transmission diversity schemes, such as combined SFBC+FSTD and STBC+TSTD, inefficiently utilize transmission antennas and power amplifiers, leading to bursty interference and degraded system performance due to '0' elements in transmission matrices, especially when increasing transmit power.
Innovation Solution
The method involves modulating data into pairs of symbols, encoding them into 2x2 matrices, orthogonally spreading these matrices using Fourier, Hadamard, or Zadoff-Chu sequences, and exchanging rows or columns to create an output matrix for transmission via multiple antennas using space-time or space-frequency diversity schemes, optimizing antenna utilization and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If combined SFBC+FSTD or STBC+TSTD schemes are used with four transmission antennas, then transmission diversity is achieved, but antenna utilization is inefficient due to '0' elements in transmission matrices
Solution Approach 1:
The transmission matrix is segmented into multiple 2x2 blocks, each corresponding to a pair of modulated symbols. This segmentation allows systematic assignment of symbols to antenna elements, eliminating the need for zero elements and improving antenna utilization while maintaining diversity.
Solution Approach 2:
The patent extends the transmission scheme from 2x2 to 4x4 matrices by adding spatial dimension (more antennas) and frequency dimension (more subcarriers). This dimensional expansion allows full utilization of all antenna elements across multiple subcarriers without introducing zero elements.
2Power
If transmit power is increased to compensate for non-zero elements, then signal strength is improved, but bursty interference is generated to neighboring cells
Solution Approach 1:
The patent ensures continuous utilization of all transmission antennas across all subcarriers by eliminating zero elements in the transmission matrix. This continuous action distributes power uniformly across all antenna elements and subcarriers, preventing the bursty interference that occurs when power is concentrated on specific antennas or subcarriers.
3Use of energy by moving object
If only a fraction of total transmission antennas are used in a given frequency resource, then power amplifier capability is underutilized, but system performance is degraded due to bursty interference
Solution Approach 1:
The patent creates a universal transmission framework where all transmission antennas are actively utilized across all allocated subcarriers. The 4x4 transmission matrix structure ensures that each antenna element contributes to multiple subcarriers, maximizing the functional utilization of power amplifier capability while maintaining system performance through uniform power distribution.
Data Source
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AI summary
A method from transmitting data via multiple antennas. The method contemplates modulating data to be transmitted into a plurality of modulated symbols, encoding each pair of modulated symbols from among said plurality of symbols in accordance with a transmission diversity scheme to result in a plurality of 2 by 2 matrices, with each 2 by 2 matrix corresponding to each pair of modulated symbols, orthogonally spreading the plurality of 2 by 2 matrices to generate an output matrix, and transmitting the symbols in the output matrix via a plurality of antennas by using either a space time transmission diversity scheme, a space frequency transmission diversity scheme, or a combination of a space time transmission diversity scheme and a space frequency transmission diversity scheme.