Both self-interference (SI), which is caused by imperfect channel estimation, and co-channel interference (CCI) are considered in multiple-input multiple-output systems employing maximal ratio combining under independ...
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Both self-interference (SI), which is caused by imperfect channel estimation, and co-channel interference (CCI) are considered in multiple-input multiple-output systems employing maximal ratio combining under independent and identically distributed Rayleigh fading. Closed-form expressions for probability density function and outage probability of output signal-to-interfer ence plus noise ratio are presented. Numerical results are used to evaluate the impact of SI and CCI.
This letter proposes a differential en/decoding scheme for multiple-input multiple-output (MIMO) communication links with distributed transmit antennas, in which neither the transmitter nor the receiver knows channel ...
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This letter proposes a differential en/decoding scheme for multiple-input multiple-output (MIMO) communication links with distributed transmit antennas, in which neither the transmitter nor the receiver knows channel knowledge. The proposed scheme is based on the layered differential space-time codes we present. Simulation results show that the bit error rate (BER) performance is nonidentical in different channel propagation delay cases. The optimum delay. time for two transmit antennas system, for example, is about 0.6T(s) (where T-s denotes symbol period) when the links achieve better performance.
This paper simulates a typical indoor MIMO-UWB OFDM system using computational electromagnetics. The goal is to create a simulation using a real world environment and taking into account realistic antenna effects. The...
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ISBN:
(纸本)9781424410422
This paper simulates a typical indoor MIMO-UWB OFDM system using computational electromagnetics. The goal is to create a simulation using a real world environment and taking into account realistic antenna effects. The effects of the wireless channel are examined on a per subcarrier basis. Analysis of the simulation results shows that the channel response and subsequently, mutual information is highly dependent on subcarrier. Furthermore, our analysis shows that by taking advantage of channel knowledge, a great increase in mutual information can be obtained. This leads to the conclusion that adaptive modulation has the potential to offer significant increase in system capacity.
In this paper we consider a cooperative communication system where some a priori information of wireless channels is available at the transmitter. Several opportunistic relaying strategies are developed to fully utili...
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ISBN:
(纸本)9781424411993
In this paper we consider a cooperative communication system where some a priori information of wireless channels is available at the transmitter. Several opportunistic relaying strategies are developed to fully utilize the available channel information. Then an explicit expression of the outage probability is developed for each proposed cooperative scheme as well as the diversity-multiplexing tradeoff by using order statistics. Our analytical results show that the more channel information available at the transmitter, the better performance a cooperative system can achieve. When the exact values of the source-relay channels are available, the performance loss at low SNR can be effectively suppressed. When the source node has the access to the source-relay and relay-destination channels, the full diversity can be achieved by costing only one extra channel used for relaying transmission, and an optimal diversity-multiplexing tradeoff can be achieved d(r) = (N + 1) (1 - 2r), where N is the number of all possible relaying nodes.
This paper investigates the performance of Super-Orthogonal Space-time Trellis Code (SOSTTC) designed primarily for non-frequency selective (i.e. flat) fading channel but now applied to a frequency selective fading ch...
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ISBN:
(纸本)9781424409860
This paper investigates the performance of Super-Orthogonal Space-time Trellis Code (SOSTTC) designed primarily for non-frequency selective (i.e. flat) fading channel but now applied to a frequency selective fading channel. A new decoding trellis is proposed for the SOSTTC in frequency selective fading environment. It was apparent that the number of state of the decoding trellis of the SOSTTC in a frequency selective channel is a function of the number of divergent paths per state, the multipath ray and the original number of states of the SOSTTC. Simulation result (i.e. frame error rate) shows that the SOSTTC in such environment (i.e. frequency selective) could not take full advantage of the multipath environment to increase coding advantage (i.e. shift of error rate curve) due to increase in parallel path of the decoding trellis. However the diversity order (i.e. slope of the error rate curve) performance is equivalent to that obtained in flat fading channel.
In this paper, we propose an efficient symbol detection algorithm and its hardware architecture for MIMO-OFDM system with two-transmit and two-receive (2x2) antennas. The detector supports two MIMO-OFDM schemes, SFBC-...
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ISBN:
(纸本)9781424410934
In this paper, we propose an efficient symbol detection algorithm and its hardware architecture for MIMO-OFDM system with two-transmit and two-receive (2x2) antennas. The detector supports two MIMO-OFDM schemes, SFBC-OFDM and SDM-OFDM, in order to achieve higher performance and throughput. However, symbol detection processes for these two schemes have high computational complexity, which is a burden to hardware implementation of MIMO-OFDM symbol detectors. In order to reduce the complexity, we propose a cost-efficient algorithm for SDM-OFDM and novel hardware architecture for MIMO-OFDM symbol detectors. The proposed detector with shared-architecture, where similar functional blocks are merged and share the hardware resources, can be used for not only SDM-OFDM but also SFBC-OFDM systems. The proposed symbol detector reduces the logic gates by 54% and the occupation ratio by 12.8% compared to a conventional symbol detector employing two individual detectors. Therefore, the proposed symbol detector will be a vast contribution to the low complexity design of MIMO-OFDM systems, since the MIMO-OFDM symbol detector is one of the largest modules in the systems,, in which the low complexity design is a very important issue.
Cooperative transmission schemes can offer benefits in terms of diversity and multiplexing gain compared with conventional direct transmission by forming a virtual antenna array. In this paper, a spectrally efficient ...
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ISBN:
(纸本)9781424403523
Cooperative transmission schemes can offer benefits in terms of diversity and multiplexing gain compared with conventional direct transmission by forming a virtual antenna array. In this paper, a spectrally efficient strategy is proposed for cooperative multiple access channels in a centralized communication environment with N users. With help of superposition coding, the deteriorating effect of cooperative communication on the data rate is effectively suppressed since relaying transmission does not consume extra channel use. By carefully categorizing the outage events, the diversity-multiplexing tradeoff can be obtained, which shows that the proposed strategy can achieve optimal tradeoff for multiplexing gains 0 <= r <= 1 whereas the compared cooperative scheme is only optimal for 0 <= r <= 1/N.
In this paper, we propose an application of cooperative system in the ad-hoc network. Based on 802.11a PHY, a compatible physical layer protocol Relay-SISO is introduced for the single-relay single-antenna system. Usi...
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ISBN:
(纸本)9781424412501
In this paper, we propose an application of cooperative system in the ad-hoc network. Based on 802.11a PHY, a compatible physical layer protocol Relay-SISO is introduced for the single-relay single-antenna system. Using Non-orthogonal Amplify-and-Forward scheme, the proposed protocol boosts quality of transmission while works at the same data rate as 802.11a with little additional preambles. Simulation results reveal the feasibility of such cooperative scheme and a significant coding gain is observed at data rate 12Mbps.
This paper considers the use of 4 x 4 multiple-input multiple-output (MIMO) antenna arrays for improving the mutual information with and without polarization diversity. The authors focus on the benefits offered by a c...
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ISBN:
(纸本)9781424412358
This paper considers the use of 4 x 4 multiple-input multiple-output (MIMO) antenna arrays for improving the mutual information with and without polarization diversity. The authors focus on the benefits offered by a combination of spatial and polarization diversity techniques. In this paper, are taken in consideration the cases where the channel state information (CSI) is known or unknown to transmitter for low signal to noise ratios (SNR) in the presence of low and high spatial correlation. The cumulative distribution function (CDF) of the mutual information is studied. We also examine the impact of cross polarization discrimination (XPD) on the mean mutual information of MIMO systems.
In this paper, we present a new iterative blind multispectral image restoration algorithm based on double regularization (DR). The motivation for DR when applied to multispectral restoration lies in its effectiveness ...
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ISBN:
(纸本)9780819469519
In this paper, we present a new iterative blind multispectral image restoration algorithm based on double regularization (DR). The motivation for DR when applied to multispectral restoration lies in its effectiveness towards edge preservation in joint blur identification and image restoration. With consideration for both the intra- and inter-channel blurring function in the multiple-input multiple-output (MIMO) systems, an alternating minimization (AM) procedure with conjugate gradient optimization (CGO) scheme is formulated to implement restoration iteratively. The derivation of DR optimization shows that optimal restoration result can be achieved even when the MIMO systems suffer from interchannel interference. Experimental results show that it is effective in performing blind mutichannel restoration when applied to color images.
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