Space-time block codes from orthogonal designs：（从正交空时分组码的设计）.pdfVIP

1456 IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 45, NO. 5, JULY 1999 Space–Time Block Codes from Orthogonal Designs Vahid Tarokh, Member, IEEE , Hamid Jafarkhani, and A. R. Calderbank, Fellow, IEEE Abstract— We introduce space–time block coding, a new par- receivers are typically required to be small, it may not be adigm for communication over Rayleigh fading channels using practical to deploy multiple receive antennas at the remote multiple transmit antennas. Data is encoded using a space–time station. This motivates us to consider transmit diversity. block code and the encoded data is split into n streams which are simultaneously transmitted using n transmit antennas. The Transmit diversity has been studied extensively as a method received signal at each receive antenna is a linear superposition of combatting impairments in wireless fading channels [2]–[4], of the n transmitted signals perturbed by noise. Maximum- [6], [9]–[15]. It is particularly appealing because of its relative likelihood decoding is achieved in a simple way through decou- simplicity of implementation and the feasibility of multiple pling of the signals transmitted from different antennas rather antennas at the base station. Moreover, in terms of economics, than joint detection. This uses the orthogonal structure of the space–time block code and gives a maximum-likelihood decoding the cost of multiple transmit chains at the base can be algorithm which is based only on linear processing at the receiver. amortized over numerous users. Space–time block codes are desi