Differential Space-Time Block Coding for High Transmission Rate
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Solution Overview
Problem
Conventional differential space-time block codes (D-STBCs) have a limited symbol transmission rate and performance degradation, particularly when using multiple transmit antennas, which restricts the system's ability to achieve high-speed communication in wireless systems prone to errors from multi-path interference and fading.
Innovation Solution
A new differential space-time block coding apparatus and method that employs a restricted symbol calculating unit and a space-time encoder to create transmission matrices with a higher symbol transmission rate, maintaining orthogonality and using multiple receive antennas to enhance performance, allowing for a double symbol transmission rate compared to conventional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional D-STBCs are used to achieve diversity gain, then reliability is improved, but transmission rate deteriorates
Solution Approach 1:
The patent changes the fundamental parameter of transmission rate by introducing a new coding scheme that allows 1.5 symbols per transmission instead of the conventional 1 symbol per transmission for two antennas, or 0.75 symbols per transmission for three or more antennas. This parameter change enables the system to achieve both high transmission rate and acceptable reliability through the proposed D-STBC structure with restricted symbols.
2Reliability
If transmit antennas are used only to acquire diversity gain, then reliability is improved, but transmission rate deteriorates
Solution Approach 1:
The patent introduces dynamic adaptability by allowing the system to switch between diversity mode and multiplexing mode based on channel conditions. The coding scheme enables the system to dynamically adjust the number of symbols transmitted per time slot, achieving 1.5 symbols/transmission for high rate or maintaining diversity gain when needed, thus adapting to varying communication requirements.
3Productivity
If channel information is used for coherent STBC, then transmission rate is improved, but device complexity deteriorates due to channel estimation overhead
Solution Approach 1:
The differential STBC scheme enables the system to operate without requiring external channel information or complex channel estimation mechanisms. The differential encoding at the transmitter and corresponding differential decoding at the receiver allow the system to self-synchronize and eliminate the need for training symbols or channel state information feedback, thereby reducing device complexity while maintaining transmission rate.
Data Source
AI summary
Disclosed is a differential space-time block coding apparatus with a high transmission rate in a wireless communication system employing multiple transmit antennas and a method thereof. The differential space-time block coding method includes the steps of, when elements of a transmission matrix B43v are transmitted in a predetermined block (a vth block) through a predetermined transmit antenna at a predetermined time, modulating a symbol Sv of inputted binary data to a symbol Sv+1, creating a matrix S44v+1 in a block (a (v+1)th block) following the predetermined block by substituting the modulated symbol for the matrix P44, and then, in order to perform a differential encoding function, multiplying the matrix B43v by the matrix S44v+1 so as to calculate a new matrix B43v+1 to be transmitted in the (v+1)th block.