MIMO Detection.pdf

The Optimized Hierarchy Reduced Search Algorithm (OHRSA) is proposed for maximum likelihood detection in multiple-antenna-aided multicarrier systems. The algorithm extends the Complex Sphere Decoder (CSD) method, reducing computational complexity while maintaining near-optimum performance.

Key aspects of the OHRSA include:

1. Recursive ML Detection: The algorithm relies on a recursive approach, using an upper-triangular matrix U to minimize the Euclidean distance between the received signal vector and the product of the channel matrix and the candidate transmitted signal vector.
2. Bitwise System Model: The algorithm represents each phasor point in an M-QAM constellation map as the inner product of a unique bit-based vector and a quantization vector, allowing for efficient processing.
3. Cumulative Sub-Cost Function: The algorithm uses a recursively defined Cumulative Sub-Cost (CSC) function to evaluate the cost of each candidate symbol vector, enabling efficient search and reduction of computational complexity.
4. Performance: The OHRSA-aided detector combines near-optimum performance with low computational complexity, making it an attractive design alternative for practical systems.

The proposed algorithm is suitable for multiple-antenna-aided multicarrier systems, including overloaded systems where the number of transmit antenna elements exceeds that of receive antenna elements. The OHRSA can be applied to various modulation schemes, including QPSK and 16-QAM.