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Recent works on massive multiple-input multiple-output (MIMO) have shown that a potential breakthrough in capacity gains can be achieved by deploying a very large number of antennas at the basestation. Although transmit-side channel state information (CSI) can be obtained by employing channel reciprocity in time division duplexing (TDD) systems, explicit feedback of CSI from the user to the basestation...
Three-dimensional (3D) MIMO is a promising enhancement of MIMO technology to improve system capacity by exploiting the spatial characteristics in both azimuth dimension and elevation dimension. As one of the key aspects in practical systems, the channel state information-reference signal (CSI-RS) design specific to future LTE-Advanced are discussed, and a precoding scheme of CSI-RS considering elevation...
This paper investigates the impact of different linear processing techniques on the outage performance of dualhop amplify-and-forward (AF) relaying systems with co-channel interference (CCI) at the multiple antenna relay. Specifically, three heuristic linear precoding schemes are proposed to combat the detrimental effect of CCI, namely, 1) Maximum ratio combining/maximal ratio transmission (MRC/MRT),...
In this paper, we study the degrees of freedom (DoF) of the MIMO relay networks. We start with a general Y channel, where each user has Mi antennas and aims to exchange messages with the other two users via a relay equipped with N antennas. Then, we extend our work to a general 4-user MIMO relay network. Unlike most previous work which focused on the total DoF of the network, our aim here is to characterize...
This paper addresses robust beamforming (BF) design for the uplink transmission of wireless networks, where the base station (BS) equipped with a very large number of antennas communicates with multiple users on the same frequency band simultaneously. Based on the assumption that the wireless channels undergo correlated Rayleigh fading, we first formulate an optimization problem to maximize the output...
We study the degrees of freedom (DoF) of MIMO two-way X relay channels. Previous work studied the case N < 2M, where N and M denote the number of antennas at the relay and each source, respectively, and showed that the maximum DoF of 2N is achievable when N < ⌊8M/5⌋ by applying signal alignment (SA) for network coding and interference cancelation. This work considers the case N > 2M where...
A multi-pair two-way relay system sharing with a single relay with large numbers of antennas is considered. In this paper, we investigate the ergodic achievable rates when maximum ratio combining/maximum ratio transmission is used at the relay station. The analytical results for the achievable rates are derived and the asymptotic analysis is conducted when the number of antennas, N, grows to infinity...
Linear precoding exploits the spatial degrees of freedom offered by multi-antenna transmitters to serve multiple users over the same frequency resources. The present work focuses on simultaneously serving multiple groups of users, each with its own channel, by transmitting a stream of common symbols to each group. This scenario is known as physical layer multicasting to multiple co-channel groups...
The K-Best algorithm can achieve high BER performance with a large K value, but the complexity is very high. The RAKB algorithm reduces the complexity and gets similar BER performance compares to the K-Best algorithm. However, with the antennas increase, the BER performance improvement of the RAKB algorithm is not obvious. This paper presents an improved algorithm which is based on the RAKB algorithm...
Channel estimation is key to enabling effective multiuser transmission in multiple-input multiple-output cellular networks. Thanks to technology advances and a shift to higher frequency carriers, recently there is an increasing interest in using very large antenna arrays at both ends of a wireless link, which is known as massive MIMO. In this work the problem of reducing large overhead due to pilot...
In this paper, a novel scheme called blind interference neutralization is provided in the 3- cell interference channel with a shared instantaneous relay. The shared relay not only receives signals from sources, but also sends signals to destinations with a processing matrix. With the proposed scheme, each destination is able to pick up its own desired signal without encountering inter-user interference...
Utilizing spatial dimensions to align interference, interference alignment (IA) techniques can greatly improve spatial multiplexing benefits in interference-limited multiple antenna systems. In this paper, we focus on the closed-form design of IA in the multi-cell multi-user interfering networks with a finite number of antennas at each node. To obtain the same degrees of freedom (DoF), existing IA...
We consider the problem of locating a sensor in a network of nodes which use inductive coupling as means of interaction. Conventional approaches in this setting require the located node to have a power supply or complex circuitry. By analysis of the circuit model underlying inductive coupling, we develop a localization method which allows for passive nodes with a simple layout. The proposed method...
This paper investigates linear precoding designs for a cooperative amplify-and-forward (AF) network with a multi-antenna relay having complete channel state information (CSI). The focus is on both orthogonal AF (OAF) and non-orthogonal AF (NAF) protocols. The precoders at the relay are derived based on the maximum ratio combining (MRC) scheme, followed by an optimal power amplification factor to maximize...
This paper presents a design of two-way two-hop relay network using physical layer network coding (PNC) in which multiple antennas are used at all nodes. For transmission over the multiple-input multiple-output channels, the Alamouti's space-time block code (STBC) is used for transmission while linear detection is used for signal estimation at all nodes. In order to facilitate linear detection, we...
This paper addresses optimum nondiagonal and diagonal amplifying relay matrices for the amplify- and-forward (AF) wireless relay networks. Single- input multiple-output (SIMO) nondistributed and distributed relaying system strategies with the relay power constraint are applied, based on the signal-to-noise ratio (SNR) criterion. By adopting the optimum amplifying relay matrices derived, the SNRs at...
In large-scale Multiple-Input-Multiple-Output (MIMO) downlink, one state-of-the-art precoder significantly reduces the Peak-to-Average Power Ratio (PAPR) of the emitted signals from the Base Station (BS) antennas through minimizing the ℓ∞-norm of the precoded signals (generated by the precoder and transmitted by the BS RF frontends). In this paper, its computational complexity is analyzed based on...
The end-to-end performance of dual-hop relaying networks with beamforming over generalized η-μ fading channels is investigated. In our analysis, we assume fixed-gain relays with single antennas, whereas the source and destination terminals are equipped with multiple antennas. Novel expressions for the generalized moments of the end-to-end signal-to-noise ratio (SNR), the cumulative density function...
Recently, promoting energy efficiency is an important research issue in the wireless communication system. This paper investigates the resource management problem with the regularized zero-forcing (RZF) precoding for the distributed large-scale multiple-input multiple-output cloud radio access network (DLS MIMO C-RAN) which consists of a large number of spatially distributed remote radio heads (RRHs)...
The degrees of freedom (DoF) of an X-network with M transmit and N receive nodes utilizing interference alignment with the support of J relays each equipped with Lj antennas operating in a half-duplex non-regenerative mode is investigated. Conditions on the feasibility of interference alignment are derived using a proper transmit strategy and a structured approach based on a Kronecker-product representation...
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