Non-unitary orthogonal differential space-time modulation with non-coherent soft-output detection

Abstract

Differential space-time modulation is an attractive alternative for mobile communications systems with multiple antennas at transmitter and/or receiver since it does not require channel estimation. Most proposals which are available in literature are based on unitary matrices which limits the achievable data rate and performance. We propose a generalized transmitter and soft-output detector for non-coherent space-time modulation which is not restricted to unitary matrices. At the transmitter, a normalization factor guarantees that the differential scheme meets a power constraint. However, this normalization factorwhich depends on the transmitted data-makes it hard to design a soft-output detector. Our main contribution is a new soft-output detector which does not require knowledge of channel coefficients, channel statistics or noise variance.

Full-rate full-diversity differential MIMO

“…Differential encoding is then performed according to equation (11). A set of 200 transmissions are generated for each channel scenario.…”

“…These noise components are uncorrelated with zero mean and variance equals to [11]. When the code is non-orthogonal, the system of equations in (2) will no longer be well-conditioned.…”

Differential Space Time Block Codes for High Mobility Scenarios

“…For a comparative evaluation of "4A16PSK PCM2" the reader can check (Xia, 2002), (Bauch, 2004), (Vanaev and Rohling, 2006), and (Fellenberg and Rohling, 2009); there different Amplitude and Phase Shift Keying (APSK) modulation schemes for DSTBC are analyzed.…”

“…If we consider a MIMO system with two transmit antennas and three receive antennas (MIMO 2x3), then six channels must be estimated and corrected in order to have an acceptable quality in the transmission. Therefore, differential coding schemes as DSTBCs have been proposed (Tarokh and Jafarkhani, 2000;Tao and Cheng, 2001;Xia, 2002;Chen et al, 2003;Hwang et al, 2003;Bauch, 2004;Bauch and Mengi, 2005), which do not need any information about the radio channel. The information is transmitted in this case as the quotient between two adjacent modulation symbols which are equally affected by the channel.…”

Precoded Differential Orthogonal Space-Time Modulation Over Correlated Ricean MIMO Channels

“…Differential-OSTBC with M -QAM constellation is discussed in [66][67][68][69][70]. Let s k,t belongs to the M -QAM constellation, then s k 2 varies from one block to the other.…”