For a family/sequence of Space-Time Block Codes (STBCs) C1, C2, . . . , with increasing number of transmit antennas Ni, with rates Ri complex symbols per channel use, i = 1, 2, . . . , the asymptotic normalized rate is defined as limi Ri Ni . A family of STBCs is said to be asymptotically-good if the asymptotic normalized rate is non-zero, i.e., when the rate scales as a nonzero fraction of the number of transmit antennas. An STBC C is said to be g-group ML-decodable if its information symbols can be partitioned into g groups, such that each group of symbols can be ML decoded independently of others. In this paper, for g 2, we construct g-group ML-decodable codes with rates greater than one complex symbol per channel use. These codes are asymptotically good too. For g > 2, these are the first instances of g-group ML-decodable codes, with rates greater than 1, presented in the literature. We also construct multigroup ML-decodable codes with the best known asymptotic normalized rates...
Natarajan Lakshmi Prasad, B. Sundar Rajan