Performance Of Space-time Block Research Articles

Performance evaluation of space time trellis coded MIMO for mobile communications

<p>The major enemy of wireless communication is multipath fading that highly degrades the received signal. Spatial diversity highly reduces deep fades of the wireless communication. Higher signal to noise ratio (SNR) requirement can be reduced by using space time coding. In this paper, the error performance of un-coded MIMO, different diversity combing methods, space time block codes and space time trellis codes are analyzed using different parameters including number of antennas, M-array modulations, trace criteria, rank and determinant. The simulation results have shown that the Bit Error Rate (BER) significantly reduces with increasing number of receiver antennas. However, the number of antennas that a mobile device can have is limited by its size and this is inconvenient for mobile communication. Hence, this paper suggests space time codes to mitigate multipath problems in mobile communication. So, BER performance of space time block codes scheme was evaluated by varying the number of transmitter and receiver antennas along with varying M-array PSK modulation orders. The results have shown that better BER is possible by integrating space time codes with spatial diversity. Finally, the error performance of space time trellis codes was evaluated by using trace, rank and determinant, and the simulation results depicted that better error performance is achieved using the proposed multipath reduction method.</p>

Double Binary Turbo Coded Data Transmission of STBC UWB Systems for U-Healthcare Applications

In this paper, we analyze and simulate performance of space time block coded (STBC) binary pulse amplitude modulation-direct sequence (BPAM-DS) ultra-wideband (UWB) systems with double binary turbo code in indoor environments for various ubiquitous healthcare (u-healthcare) applications. Indoor wireless channel is modeled as a modified Saleh and Valenzuela (SV) model proposed as a UWB indoor channel model by the IEEE 802.15.SG3a in July 2003. In the STBC encoding process, an Alamouti algorithm for real-valued signals is employed because UWB signals have the type of real signal constellation. It is assumed that the transmitter has knowledge about channel state information. From simulation results, it is shown that the STBC scheme does not have an influence on improving bit error probability performance of the BPAM-DS UWB systems. It is also confirmed that the results of this paper can be applicable for u-healthcare applications.

A dual combining based decoding scheme for two-branched mobile STBC

In this paper, a dual combining based decoding scheme is proposed to enhance the detection performance of space-time block coding with two transmit antennas in a highly time-varying mobile channel. The proposed scheme analyzes the signal-to-noise ratio and signal-to interference plus noise ratio of decision variables for a zero-forcing combiner (ZFC) and a matched filter combiner (MFC), respectively. Based on the analysis, we derive a sophisticated decoding scheme which utilizes tentative detection symbols of the ZFC based decoder to cancel inter-symbol interference from the decision variables of the MFC. Computer simulations show that the proposed scheme outperforms the conventional decoding scheme with the ZFC or the MFC.

ERROR PROBABILITY OF SPACE-TIME BLOCK CODED SYSTEMS IN MULTIPATH RAYLEIGH CHANNEL: MLSE AND SUBOPTIMUM DECODING

In this paper, we address the error probability performance of space-time block coded system (STBC) in multipath Rayleigh fading channel. We consider STBC with rate one for two transmit antennae and rate half for three transmit antennae, and present an optimal maximum-likelihood-sequence-estimation (MLSE) and a block-by-block suboptimum decoding receiver structures. The proposed receiver schemes are suitable for short-range wireless communication or wireless personal area network (WPAN), where the delay spread is usually smaller than one symbol period. A reduced-state MLSE receiver with new trellis structure is first developed for the multiple-input multiple-output (MIMO) scenario assuming availability of ideal channel state information (CSI). Then a less complex block-by-block suboptimum decoding algorithm is also developed for the unequalized multipath fading channel, as an alternative to the computationally intensive MLSE. The suboptimum receiver symbol timing is optimized in order to obtain minimum error probability for the general multipath power delay profiles. From our simulation results, we show that our proposed MLSE receiver can mitigate the multipath induced intersymbol interference (ISI) effectively and at bit error rate (BER) of 10-3, a two-transmit and two-receive (2, 2) STBC system gains as much as 11.5 dB in SNR over a single-antenna uncoded system. We also verify that the MLSE receiver always outperforms the suboptimum receiver, as expected. Error floors appear in the BER performance curves of the suboptimum receiver because ISI is not equalized, whereas no such floors appear with the MLSE receiver.

Investigation on the performance of space‐time block coded ultrawide band communication systems

AbstractUltrawide band (UWB) communication systems show many advantages over the conventional narrow band systems. In this paper, three UWB systems at the same transmission efficiency are investigated. The first one is a conventional system with only one transmit antenna (non‐STBC). The second one is combined with the space‐time block coding (STBC) over one symbol (STBC‐1). The third system is combined with the STBC over two symbols (STBC‐2), which is in accordance with Almouti's scheme. Both theoretical analysis and simulations show that the STBC‐1 system performs the best. In addition, the adoption of the normalized modified Hermite polynomial based orthogonal pulses (NMHP) instead of the Gaussian pulse (GP) to represent the M‐ary symbol constellation can increase the data rate and lead to an improvement of the signal to noise ratio (SNR) by about 10log10M dB at the bit error rate (BER) of 10−4 at any symbol constellation for any UWB system. The simulations in both flat‐fading channels and frequency‐selective channels have confirmed such improvement. Copyright © 2005 John Wiley & Sons, Ltd.

Performance of space-time block coded MC-CDMA in Nakagami fading channels

The performance of a space-time block coded multicarrier code-division multiple-access (MC-CDMA) system operating in Nakagami-m fading channels is investigated. A new explicit closed form expression for bit error probability is derived. The accuracy of the analytical method is verified by computer simulations.