Optimal Modulation Design for MIMO Communication

Precoding and modulation are important modules in wireless transmissions. Precoding designs improve the spectral efficiency and system performance in multi-input multi-output (MIMO) systems. Modulation is the process of varying one or more properties (amplitude, phase, and/or frequency) of a carrier signal, with information, e.g., bits, to be transmitted.

Existing modulation methods for wireless communication primarily are designed in a complex-valued plane, i.e., focusing on the in-phase and quadrature (I/Q) components. Current communication methods utilizing MIMO systems include separately designed modulations for each sub-channel and provide sub-optimal approaches for symbol error rate (SER) reduction due to independent design and the use of regular structures for symbols.  This process introduces novel concepts to improve SER performance and enhance the efficiency of MIMO systems.

Mojtaba Vaezi, PhD, Director of Wireless Networking Laboratory, Associate Professor, in the Department of Electrical and Computer Engineering at Villanova University has developed an apparatus and method to improve bit error rates within wireless communications.  The invention provides

• A hybrid or unified approach that includes constellation generation and precoding into a fully integrated MIMO system;
• Multiple-input and multiple-output systems to enlarge dimensions of constellation space, improving symbol error rate and point-to-point transmission performance; and
• Deployment of Mahalanobis distance to separate symbols within the constellation.

 

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