Space-Time-Frequency Coding Orthogonal Mapping
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Solution Overview
Problem
Current wireless communication systems face limitations in achieving high transmit diversity gain, particularly in multi-path fading environments, where existing space-time-frequency coding techniques only provide one-dimensional diversity gains.
Innovation Solution
A method and apparatus for space-time-frequency encoding that allocates channel elements to achieve orthogonality in both space-time and space-frequency domains, resulting in two-dimensional transmit diversity gain by transforming input element pairs into orthogonal pairs and mapping them to time-frequency matrices for transmission via different antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional space-time or space-frequency encoding is used, then one-dimensional transmit diversity gain is achieved, but two-dimensional transmit diversity gain cannot be obtained
Solution Approach 1:
The patent extends conventional one-dimensional space-time or space-frequency encoding by introducing a second dimension of orthogonality. Specifically, it creates encoding schemes where transmitted signals are orthogonal both in the space-time domain and in the space-frequency domain simultaneously, thereby achieving two-dimensional transmit diversity gain without proportionally increasing system complexity
Solution Approach 2:
The patent combines space-time block coding and space-frequency block coding into a composite encoding scheme. By integrating both encoding dimensions into a unified framework, the system achieves the benefits of both space-time and space-frequency diversity while maintaining a structured approach that manages complexity through systematic design
2Reliability
If orthogonal design is adopted for space-time-frequency coding, then transmit diversity gain is improved, but decoding complexity increases
Solution Approach 1:
The patent segments the decoding process into distinct stages corresponding to the different orthogonal dimensions. By separating space-time decoding operations from space-frequency decoding operations, the system manages complexity through modular processing rather than requiring simultaneous handling of all dimensions at once
Solution Approach 2:
The patent implements orthogonal designs that provide sufficient orthogonality to achieve the required diversity gain while avoiding excessive complexity. The encoding schemes are designed to create the minimum necessary orthogonal structure to obtain two-dimensional diversity benefits without over-engineering the system
Data Source
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AI summary
The invention relates to a space-time-frequency encoding for use in wireless communication systems. According to the encoding scheme provided by the invention, it first transforms a plurality of input element pairs into a plurality orthogonal element pairs respectively, each of the plurality of input element pairs and corresponding orthogonal element pair forming an orthogonal matrix; and then maps the first element, second element and the redundancy of the second element in each of the plurality of input element pairs and corresponding orthogonal element pair as channel elements to three predetermined time-frequency cells in a first and second two-dimension time-frequency matrix so as to make the channel elements in the first and second matrixes suitable for being transmitted via different antennas. As the redundant input element pairs and corresponding orthogonal element pairs transmitted via different antenna are orthogonal in both space-time domain and space-frequency domain at the same time, and thus two-dimension space-time transmit diversity gain and space-frequency transmit diversity gain can be achieved at the same time.