Precoding Matrix Power Balancing via Alphabet Modification
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Solution Overview
Problem
In MIMO-based communication systems like LTE, maintaining power balancing in precoding matrices across antennas is challenging, especially when using limited alphabets such as M-PSK, which can lead to suboptimal utilization of power amplifier resources and computational complexity issues.
Innovation Solution
The method involves generating a precoding matrix as the Hadamard product of an alphabet modifying matrix and an original precoding matrix with complex coefficients of equal magnitude, allowing for power balancing by incorporating zero or scaled amplitude values, thereby ensuring balanced power distribution across antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a limited alphabet (e.g., M-PSK) is used for precoding coefficients, then computational complexity is reduced, but power balancing across antennas deteriorates
Solution Approach 1:
The patent changes the parameter set by introducing an extended alphabet that includes zero values alongside M-PSK values. This allows the precoding coefficients to take on zero values for power balancing while maintaining the low-complexity M-PSK structure for non-zero entries, thus resolving the contradiction between computational complexity and power balancing precision
Solution Approach 2:
The patent segments the precoding coefficient selection into two parts: M-PSK values for maintaining low computational complexity and zero values for achieving power balancing. This segmentation allows the system to benefit from both approaches simultaneously
2Device complexity
If M-PSK alphabet is used for precoding coefficients, then computational complexity is reduced, but power amplifier utilization deteriorates
Solution Approach 1:
By extending the M-PSK alphabet to include zero values, the system can now achieve full power amplifier utilization through the zero-forcing capability, while maintaining the low computational complexity of M-PSK for the non-zero coefficients
3Manufacturing precision
If different amplitude values are allowed in precoder, then power balancing is improved, but computational complexity increases
Solution Approach 1:
Instead of allowing continuous amplitude variations which would increase complexity, the patent discretizes the amplitude parameter by introducing zero as a specific amplitude value in the extended alphabet, achieving power balancing with minimal increase in computational complexity
Solution Approach 2:
The patent uses a simple extension of the existing M-PSK alphabet rather than implementing a completely new complex amplitude modulation scheme, thus achieving power balancing with minimal additional complexity
Data Source
AI summary
The invention relates to a method for operating a secondary station in a communication network including a primary station, the method comprising generating a precoding matrix obtained from the Hadamard product of an alphabet modifying matrix and an original precoding matrix, wherein the original precoding matrix consist of complex coefficients of equal magnitude, transmitting a precoding report representative of the precoding matrix to the primary station.