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An iterative least-squares (RLS) anti-jamming technique is applied to a conformal antenna for improving the adaptive anti-jamming performance. This method offers a solution to synthesize predefined radiation pattern. By iterative calculation, a set of constraint weights of linearly constrained minimum variance (LCMV) can be obtained to improve the adaptive nulling depth and to expand the angle coverage...
This study concerns about Beamforming techniques in a Multi-User Indoor environment at mm-Wave E-band. Directional mm-Wave measurement data are used as reliable radio channel reference for the study and, furthermore, are checked against advanced Ray Tracing simulations. The main goal is to assess the quality of Spatial Division Multiple Access using three different Beamforming schemes in order to...
In this paper we consider transmit beamforming schemes for downlink control channel. In particular, we propose exploiting information on user location for selecting both the serving transmission/reception point (TRP) and transmit beam used for control channel transmissions. Moreover, a suppressed zero-forcing (SZF) scheme based on vertically and horizontally polarized transmit beams is proposed with...
Virtual cell (VC) is an emergent concept in cellular networks that shifts the base-station-centric point of view to a user-centric one. Instead of traditional base station assignment, VCs contain a number of transmission points with an association pattern that is created for, and moves with, every user in the network. This study targets VCs for vehicle-to-everything (V2X) communications, where V2X...
The transceiver beamforming design problem is studied in this paper for a multi-pair two-way distributed relay network, where multi-antenna users in one user group communicate with their partners in the other user group via distributed single-antenna relay nodes. An iterative algorithm is proposed where transmit and receive beamformings are performed at user nodes, and relay nodes have their own simple...
This paper investigates scheduling and precoding techniques via hybrid analog-digital transmitters in mm-wave frequency bands. As in spectrum sharing sub-6GHz scenarios, the presence of non-intended receivers limits the overall achievable rates. In order to circumvent this problem, we propose a scheduling and precoding algorithm able to maximize the sum-rate while keeping the interference to the external...
In this work, we present a novel robust distributed beam-forming (RDB) approach to mitigate the effects of channel errors on wireless networks equipped with relays based on the exploitation of the cross-correlation between the received data from the relays at the destination and the system output. The proposed RDB method, denoted cross-correlation and subspace projection (CCSP) RDB, considers a total...
In this work, we propose a beam selection scheme that exploits the geometric sparsity of the multi-user (MU) massive multiple input and multiple output (MIMO) channel, using its beamspace representation. Assuming knowledge of the beamspace channel, the beamspace precoder consists in selecting and weighting the beams steered to the users, in order to maximize the signal-to-interference-and-noise ratio...
Beamforming is a signal processing technique in which multiple antennas are used to weight the signals so that they can be added constructively in the desired direction, and destructively in the interference direction. In this paper, adaptive beamforming based on subband decomposition structure is investigated in smart antenna arrays and the performance of the proposed adaptive beamforming scheme...
With the densification of heterogeneous networks in terms of both users and base stations (BS) being identified as an integral part of future communication systems, the problem of association needs to be reconsidered since conventional schemes which are simply based on the received signal strength lead to small cells being idle. Coordinated multipoint (CoMP) techniques show great potential in improving...
This work deals with a joint design of radio access and fronthaul links for the uplink of cloud radio access network (C-RAN) equipped with wireless fronthaul link. A conventional uplink system based on per-cell decode-and-forward (DF) relaying, in which the message sent by each user equipment (UE) is decoded by the closest remote radio head (RRH) and forwarded to a baseband processing unit (BBU) via...
We consider wireless information and power transfer in a multi-user massive multiple-input multiple-output (MU-Massive-MIMO) system, where several distributed antenna sets, also denoted as remote radio heads (RRHs), are deployed, while the users can simultaneously perform information detection and energy harvesting. Assuming a large number of antennas and autonomous power allocation for the information...
A scenario consisting of several cells is considered where each cell contains a multiple-antenna enhanced remote radio head (eRRH) and several single-antenna mobile stations (MSs). All eRRHs can access the cloud with limited capacity fronthaul links. The beamforming problem aiming at maximizing the sum rate with per eRRH power constraint is considered. In this paper, a hierarchical one-shot top-down...
One key requirement for the fifth-Generation (5G) mobile system is the enhancement of cell edge user performance to ensure that every user is supported with consistent experience anywhere in the network. An active interference design to improve anywhere performance, particularly in the low SINR regime, can be achieved by applying a recently proposed new type of modulation scheme, frequency quadrature-amplitude...
In the ultra dense network (UDN), user-centric virtual cell (VC) has been proposed to weaken the traditional concept of base station centric cell, where each user is served by several transmit points (TPs). The overlapped VCs in UDN will result in severe inter-VC interference and degrade the system throughput. Merging overlapped VCs can transform the serious inter-VC interference into intra-VC interference,...
In this paper, we consider a heterogeneous cellular network with a macrocell and several femtocells. In each femtocell, the femto base station (FBS) serves one femto user (FU), which is capable of simultaneous wireless information and power transfer (SWIPT) energy harvesting (EH) in a power splitting manner. All FBSs suppress their interference to macro users (MUs) via a interference power constraint...
With the growth of mobile data application and the ultimate expectations of 5G technology, the need to expand the capacity of the wireless networks is inevitable. Massive MIMO technique is currently taking a major part of the ongoing research, and expected to be the key player in the new cellular technologies. This papers presents an overview of the major aspects related to massive MIMO design including,...
The new networking paradigm of opportunistic spectrum sharing is a promising technology for mitigating the scarcity of spectrum, which has resulted from the exponential increase in the number of wireless devices and ubiquitous services. In light of the new concept of Authorized/Licensed Shared Access (ASA/LSA), in this work, we consider the coexistence and spectrum sharing between a collocated multiple-input-multiple-output...
In this paper, we propose a joint analog-digital (AD) beamforming scheme that exploits the mutual coupling effect to further improve the performance of multi-user multiple-input single-output (MU-MISO) systems. We firstly propose a joint AD scheme by iteratively optimizing the beamforming vectors in the digital domain and the load impedances of each antenna element in the analog domain. We further...
In this paper, we consider the joint multicast and unicast beamforming design problem in the multi-input single-output downlink wireless network, where all base stations (BSs) potentially can cooperate (as a single virtual BS) to transmit a common multicast and multiple dedicated unicast data streams at the same time on the same frequency band. To reduce cooperation overhead (among different BSs),...
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