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A cross layer approach based on adaptive modulation and automatic repeat request protocol in multi antennas systems to maximize the overall throughput and guarantee the packet error rate has been presented. The performance of the cross layer design in the MIMO Rician channel is investigated using the average spectral efficiency as the performance metric. The results show the advantages of cross layer...
In this paper a multi-input multi-output (MIMO) communication system is considered in which a relay with multiple antennas is used to assist the data transmission from the source to destination. We assume that the relay applies a linear transform matrix on its received signal vector and retransmit the transformed vector to the destination node. We optimize the transform matrix by maximizing the average...
Distributed antenna system (DAS) constitutes one of the most fascinating schemes to efficiently achieve the rigorous quality of service demands of next generation wireless networks. System level simulation (SLS) approach is considered since things are too complicated to be dealt only analytically and it would not be cost-effective to deploy all the real scenario to test every feature.In this paper,...
The CP-free MIMO-OFDM system is considered to be an alternative to improve the spectral efficiency of the CP-MIMO-OFDM system. In this paper, we investigate the performance of the CP-free ST-BC MIMO-OFDM system under the effects of non-linear distortion due to HPA in the transmitter, and IQ-imbalance in the receiver. We first show that with the ST-BC encoder the constraint of the CP-free MIMO-OFDM...
This paper presents new transceiver framework for the DS-CDMA systems that use the multiple-input multiple-output (MIMO) antennas, with space-time block code (ST-BC). In the transmitter, new hybrid (prefix/postfix) zero-padding sequences combining with the desired user signature is exploited to form the hybrid augmented user signature sequences, with respect to different transmit-antennas. While in...
The asymptotic performance of transmit antenna selection (TAS) in a two-hop amplify-and-forward (AF) MIMO relay network over Rayleigh-fading channels is analyzed. Assuming that the source and destination are equipped with NS and ND antennas, respectively, and communicate with each other with the help of an NR-antenna relay, we derive closed-form statistics of received signal-to-noise ratio (SNR) around...
We examine the distribution of the per virtual-channel received signal-to-noise ratio over a multiple-input multiple-output channel modeled by a rank-2 non-central Wishart matrix. The exact probability density function is derived for all possible non-centrality matrices; and verified through simulation for selected systems. Identities for exact analytic results on the outage probability, the average...
In this paper, we present a general analytical framework for the exact mutual information (MI) cumulants of multiple-input multiple-output (MIMO) systems with perfect receiver channel state information (CSI) and no transmitter CSI. Our derivation is based on a recent parameterization of the joint ordered eigenvalue probability density function (PDF), that encompasses both uncorrelated/semi-correlated...
In this paper we examine the use of generalized singular value decomposition (GSVD) for coordinated beamforming in MIMO systems. GSVD facilitates joint decomposition of a class of matrices arising inherently in source-to-2 destination MIMO broadcast scenarios. GSVD allows two channels of suitable dimensionality to be jointly diagonalized, i.e. to be reduced to non-interfering virtual broadcast channels,...
We present a distributed joint power control and transmit beamforming selection scheme for multiple antenna wireless ad hoc networks. Under the total network power minimization criterion, a joint iterative beamforming and power control algorithm is proposed to reduce mutual interference at each node. Total network transmit power is minimized while ensuring a constant received signal-to-interference...
Modulation type is one of the most important characteristics used in signal waveform identification and classification. In this paper, an algorithm for blind digital modulation identification for multiple-input multiple-output (MIMO) systems is proposed. The suggested algorithm is verified using higher order statistical moments and cumulants of the received signal. A multi-layer neural network trained...
In this contribution, we propose an antenna selection scheme in dual-hop amplify-and-forward (AaF) multiple-input multiple-output (MIMO) relaying in Nakagami-m fading channels. In each hop, the transmit and receive antenna pair that maximizes the instantaneous signal-to-noise ratio (SNR) at the receiver is selected for transmission. We derive new closed-form expressions for the exact outage probability...
As the demand for mobile broadband services are growing, cellular networks are heading towards their fourth generation (4G). Long Term Evolution (LTE) is emerging as a major candidate for 4G cellular networks. 4G networks are to support a myriad of applications which have different error tolerance and delay requirements. MIMO (Multiple Input Multiple Output) technology combined with OFDMA and more...
In this paper, we are concerned with low-complexity detection in large multiple-input multiple-output (MIMO) systems with tens of transmit/receive antennas. Our new contributions in this paper are two-fold. First, we propose a low-complexity algorithm for large-MIMO detection based on a layered low-complexity local neighborhood search. Second, we obtain a lower bound on the maximum-likelihood (ML)...
Alternating minimization algorithms are typically used to find interference alignment (IA) solutions for multiple-input multiple-output (MIMO) interference channels with more than K=3 users. For these scenarios many IA solutions exit, and the initial point determines which one is obtained upon convergence. In this paper, we propose a new iterative algorithm that aims at finding the IA solution that...
In this paper we consider the design of multi-stream demodulators for multiple-input multiple-output (MIMO) systems. Our proposed MIMO demodulator is based on the stack tree-search strategy and provides soft-outputs in the form of exact max-log log-likelihood ratios (max-log LLRs). We prove that our proposed demodulator is optimally efficient in that it visits the least number of nodes among all optimal...
We consider a multicell random beamforming scheme where a cooperative base station (BS) can simultaneously beamform to its served (local) user via utilizing perfect channel state information and randomly beamform to its neighboring users. The rationale behind this scheme is to curtail channel information feedback in a multicell MIMO system. By sharing antenna degree of freedom and transmit power at...
We develop an interference alignment (IA) technique for a downlink cellular system. In the uplink, IA schemes need channel-state-information exchange across base-stations of different cells, but our downlink IA technique requires feedback only within a cell. As a result, the proposed scheme can be implemented with minimal changes to an existing cellular system where the feedback mechanism (within...
The Golden Code is a full-rate full-diversity space-time code, which achieves maximum coding gain for Multiple-Input Multiple-Output (MIMO) systems with two transmit and two receive antennas. Since four information symbols taken from an M-QAM constellation are selected to construct one Golden Code codeword, a maximum likelihood decoder using sphere decoding has the worst-case complexity of O(M4),...
This paper focuses on the feedback scheme for downlink Multi-User Multiple-Input Multiple-Output (MU-MIMO) transmission with linear precoding. When the maximum transmission rank per user is limited to one, the multiple-antenna receiver uses a weight vector to transform MIMO channel matrix into an equivalent Multiple-Input Single-Output (MISO) channel vector. Then a Channel Directional Index (CDI)...
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