Transmit phase control to increase the minimum eigenvalue of channel correlation matrix in the E-SDM/OFDM system
01 Dec 2004-Vol. 3, Iss: 3, pp 2024-2028
TL;DR: In this article, an E-SDM/OFDM system with transmit phase control was proposed to improve the bit error rate (BER) performance of the data stream multiplied by the minimum eigenvalue.
Abstract: In multiple-input multiple-output (MIMO) systems, the eigen-beam space division multiplexing (E-SDM) system has been proposed for mitigating the effect of co-channel interference (CCI). Received signal to noise ratio (SNR) in the E-SDM system depends on the eigenvalues of the channel correlation matrix. Consequently, the bit error rate (BER) performance of the data stream multiplied by the minimum eigenvalue is degraded in comparison with that of another data stream. We propose an E-SDM/OFDM system to control the eigenvalues of a channel correlation matrix by using transmit phase control. Computer simulation results indicate the proposed E-SDM/OFDM system with transmit phase control can improve the BER performance compared with E-SDM/OFDM system without using transmit phase control.
Citations
More filters
01 Jan 2007
TL;DR: This thesis provides some analytical methodologies to investigate the variation of MIMO eigenmodes and derives accurate analytical approximations for the level crossing rate (LCR) and average fade duration (AFD) of the MIMModes in an independent, identically distributed flat-fading channel.
Abstract: Many recent research results have concluded that the multiple-input multipleoutput (MIMO) wireless communication architecture is a promising approach to achieve high bandwidth efficiencies. MIMO wireless channels can be simply defined as a link for which both the transmitting and receiving ends are equipped with multiple antenna elements. This advanced communication technology has the potential to resolve the bottleneck in traffic capacity for future wireless networks. Applying MIMO techniques to mobile communication systems, the problem of channel fading between the transmitters and receivers, which results in received signal strength fluctuations, is inevitable. The time-varying nature of the mobile channel affects various aspects of receiver design. This thesis provides some analytical methodologies to investigate the variation of MIMO eigenmodes. Although the scope is largely focussed on the temporal variation in this thesis, our results are also extended to frequency variation. Accurate analytical approximations for the level crossing rate (LCR) and average fade duration (AFD) of the MIMO eigenmodes in an independent, identically distributed (i.i.d.) flat-fading channel are derived. Furthermore, since several channel metrics (such as the total power gain, eigenvalue spread, capacity and Demmel condition number) are all related to the eigenmodes, we also derive their LCRs and AFDs using a similar approach. The effectiveness of our method lies in the fact that the eigenvalues and corresponding channel
10 citations
References
More filters
15 May 2000
TL;DR: An analysis is made of maximum likelihood decoding in a wireless space division multiplexing (SDM) link, where information is transmitted and received simultaneously over several transmit and receive antennas to achieve large data rates and high spectral efficiencies.
Abstract: An analysis is made of maximum likelihood decoding (MLD) in a wireless space division multiplexing (SDM) link, where information is transmitted and received simultaneously over several transmit and receive antennas to achieve large data rates and high spectral efficiencies. It is proven that maximum likelihood decoding obtains a diversity order equal to the number of receive antennas, independent of the number of the transmit antennas, while conventional processing techniques such as the minimum mean square error (MMSE) technique obtain a diversity order equal to the number of receive antennas minus the number of transmit antennas plus one. Hence, compared to conventional techniques, maximum likelihood decoding has a significant signal-to-noise ratio advantage which grows with the number of transmit antennas. Maximum likelihood decoding even works when the number of transmit antennas is larger than the number of receive antennas, which is not possible for conventional techniques.
217 citations
10 Dec 2002
TL;DR: In this paper, a method to assign both bit and transmit power to each substream based on the criterion minimizing total bit error rate (BER) is developed, and the BER performance is numerically analyzed in comparison to spatial division multiplexing (SDM).
Abstract: When channel state information is known at a transmitter in multiple-input multiple-output systems, the optimum capacity is given by eigenmode channel division with water-pouring power control. In this eigenbeam-space division multiplexing (E-SDM), bit assignment to substreams based on the capacity is not optimum due to the fact that the number of assigned bits is expressed by a discrete quantity. In the paper, a method to assign both bit and transmit power to each substream based on the criterion minimizing total bit error rate (BER) is developed, and the BER performance is numerically analyzed in comparison to spatial division multiplexing (SDM). The simulation results assuming 5-transmit and 2-receive antennas show that the E-SDM provides about 10 dB gain compared to the conventional SDM at average BER of 10/sup -3/.
157 citations
01 Jan 2002
TL;DR: In this article, the authors proposed an OFDM/SDM system with transmitting phase control to reduce the probability of MLE detection error and showed that the proposed system can improve the BER performance compared with the system without phase control.
Abstract: In order to realize a high data rate, the orthogonal frequency division multiplexing (OFDM) system using space division multiplexing (SDM) has been proposed. In the OFDM/SDM system, previous studies have shown that the maximum likelihood estimation (MLE) has the best bit error rate (BER) performance. However, if the received powers of the desired symbols from different antennas are nearly the same and the desired symbols are received with specific phase difference, the MLE technique cannot work well, because almost the same replicas are generated. In order not to generate the same replicas in the MLE detection and to reduce the probability of MLE detection error, we propose an OFDM/SDM system with transmitting phase control. By using the computer simulation, we show that the proposed system can improve the BER performance compared with the system without phase control.
2 citations