Transmit FDE weight design for single-carrier space-time block coded joint transmit/receive diversity

Abstract

Abstract-Single-carrier (SC) transmission using frequencydomain space-time block coded joint transmit/receive diversity (FD-STBC-JTRD) combined with transmit frequency-domain equalization (FDE) obtains full spatial diversity gain and frequency diversity gain. Channel state information (CSI) is required only at transmitter for transmit FDE. In our previous study of SC FD-STBC-JTRD, single transmit FDE weight matrix was used. In this paper, noting that a sequence of data blocks is STBC encoded into a code-word composed of a new sequence of coded data blocks, we derive the optimal transmit FDE weight design. Multiple transmit FDE weight matrices, each associated with each coded block in a STBC code-word, are used unlike our previous transmit FDE weight design. Transmit FDE weight matrices are jointly optimized based on the minimization of the mean square error (MSE) between the transmitted signal before STBC encoding and the received signal after STBC decoding. We show by theoretical analysis that the optimal transmit FDE weight design can achieve 1/R STBC times higher signal-tointerference plus noise power ratio (SINR) than our previous design (single transmit FDE weight matrix), where R STBC denotes the STBC coding rate. And then, we show, by computer simulation, the optimal transmit FDE weight design achieves better bit error rate (BER) performance than our previous design.

Performance Analysis of Space-Time Block Coded Joint Tx/Rx Diversity Using Optimal Transmit FDE in Presence of Channel Estimation Error

“…3(a) that the optimal transmit FDE can achieve better BER performance than the conventional transmit FDE even in the presence of CSI error when N r >2. This is because the optimal transmit FDE matrices are sparse and the norm of the optimal transmit FDE matrix is smaller than that of the conventional transmit FDE [12]. When N r =4, the optimal transmit FDE reduces the transmit E b /N 0 required for BER=10 4 by about 1.2 dB compared to the conventional transmit FDE.…”

“…Recently, we pointed out that the use of single weight matrix over a STBC code-word does not necessarily minimize the mean square error (MSE) between the transmit signal before STBC encoding and the received signal after STBC decoding [12]. Later, we derived the optimal transmit FDE for SC FD-STBC-JTRD based on the MMSE criterion [12].…”

“…Later, we derived the optimal transmit FDE for SC FD-STBC-JTRD based on the MMSE criterion [12]. Instead of using the single weight matrix, the multiple transmit FDE matrices are used corresponding to multiple coded blocks in a STBC code-word.…”

“…Instead of using the single weight matrix, the multiple transmit FDE matrices are used corresponding to multiple coded blocks in a STBC code-word. The optimal transmit FDE achieves the received signal-to-interference plus noise power ratio (SINR) 1/R STBC times higher than the conventional transmit FDE which uses the single weight matrix over a STBC code-word, where R STBC denotes the STBC code rate [12].…”

“…Thus, how the CSI error affects the FD-STBC-JTRD performance is a practically important problem. However, in our study in [12], ideal channel estimation was assumed. Least square channel estimation (LSCE) [13] and code-multiplexed pilot based channel estimation (CMP-CE) [14] can simultaneously estimate all transmit/receive antenna pairs.…”