Multi-QAM Modulation: A Low-Complexity Full-Rate Diversity Scheme

To exploit channel diversity without loss in transmission rate, a signal space diversity method can be used. Most existing signal space diversity techniques either require very high degree of computational complexity or have sub-optimal performance. We propose a signal space diversity technique, called Multi-QAM modulation, where data bits are directly modulated over multiple QAM constellations. We design constellation sets that not only can achieve full degree of diversity at full rate, but also allow implementation of receivers that can achieve near optimal performance with low computational complexity.