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In this paper, we focus on the millimeter-wave multi-user multiple-input-multiple-output (mmWave MU-MIMO) systems and propose a low-complexity hybrid precoding and combining design, which is applicable to both fully-connected structures and sub-connected structures. Based on the channel knowledge of each user, the analog combiner for each user is independently designed based on the singular value...
Non-orthogonal multiple access (NOMA) has attracted a lot of attention recently due to its superior spectral efficiency and could play a vital role in improving the capacity of future networks. This paper considers resource allocation for a downlink, multi-user (MU) MIMO-NOMA system that aims at maximizing the sum rate with interference alignment (IA) technique. Using singular decomposition value...
In this paper, a multi-group multi-way relaying network is considered. Multiple half-duplex nodes form a group and each node wants to share its message with all other nodes in its group via an intermediate half-duplex relay. The nodes of the whole network are equally distributed over the groups. In this paper, we propose a multicast interference alignment algorithm for a multi-group multi-way relay...
We perform an asymptotic study on the performance of filter bank multicarrier (FBMC) in the context of massive multi-input multi-output (MIMO). We show that the signal-to-interference-plus-noise ratio (SINR) cannot grow unboundedly by increasing the number of base station (BS) antennas, and is upper bounded by a certain deterministic value. This is a result of the correlation between the multi-antenna...
Vehicular Ad-hoc Networks (VANETs) is a wireless networking technology that can be used to support the emergence of Intelligent Transportation Systems (ITS). The deployment of these systems will allow connected vehicle to communicate each other and also with the road side infrastructures in order to avoid possible accidents and provide more comfort applications to the driver and passenger. The designers...
Massive MIMO technology can increase capacity, data rate, and link reliability significantly without additional bandwidth or transmission power. Most of the previous study on Massive MIMO systems are using low frequency (2.6 GHz). This frequency is not suitable for future broadband technology, because IoT devices will use high frequency and possible cell coverage would be smaller. This work proposes...
This work deals with beamforming for the MaMISO Interfering Broadcast Channel (IBC), i.e. the Massive Multi-Input Single-Output (MaMISO) Multi-User Multi-Cell downlink (DL). The novel beamformers are here optimized for the Expected Weighted Sum Rate (EWSR) for the case of Partial Channel State Information at the Transmitters (CSIT). Gaussian partial CSIT can optimally combine channel estimate and...
This paper studies the impact of in-phase and quadrature imbalance (IQI) on the downlink of a single-cell multiuser multiple-input multiple-output (MU-MIMO) system with large antenna arrays. Moreover, we consider a time-division duplex (TDD) system where we assume uplink/downlink channel reciprocity in the downlink precoding design. We study the impact of uplink/downlink channel mismatch on the downlink...
In this paper, the problem of sequential beam construction and adaptive channel estimation based on reduced rank (RR) Kalman filtering for frequency-selective massive multiple-input multiple-output (MIMO) systems employing single-carrier (SC) in time division duplex (TDD) mode are considered. In two-stage beamforming, a new algorithm for statistical pre-beamformer design is proposed for spatially...
Mobile Edge Computing (MEC) plays a key role in the 5G roadmap, as a way to bring information technology (IT) services closer to the mobile users by empowering radio access points with additional functionalities, like caching or computation offloading capabilities. At the physical layer, some of the key technologies enabling very low latency mobile services are dense deployment of radio access points,...
In this study, outage probability of partial antenna selection in the full-duplex decode-and-forward multiple-input multiple-output relay networks is investigated over Rayleigh fading channels. In the considered relay network the source, relay and destination are equipped with multiple antennas and it is assumed that direct link is not available due to heavy channel conditions. For signal transmission...
Multiple receive and transmit antennas can be used to improve the spectral efficiency by transmitting over multiple independent streams. In addition, multiple receive antennas facilitate interference suppression through the use of interference rejection combining receivers. Rank adaptation algorithms are aimed at balancing the trade-off between increasing the spatial gain, and improving the interference...
Time-shifted pilot scheme can efficiency combat pilot contamination. However, when the number of base station (BS) antennas is finite, the pilot interference due to the downlink transmission symbols cannot be mitigated in the time-shifted scheme. This paper proposed a novel two-stage channel estimation algorithm based on time-shifted pilot to reduce the effect of pilot interference. In the first stage,...
Multiple-input multiple output (MIMO) systems are able to serve multiple users simultaneously and using the same frequency band. Therefore, they have a quite crucial position in the design of 5G and future communication systems. However, as the number of users to be served increases, they may fail to suppress the inter-user interference adequately. It has been shown in literature that increasing the...
In this article, we investigate how the performance of Massive MIMO cellular systems can be enhanced by introducing D2D communication. We consider a scenario where the base station (BS) is equipped with large, but finite number of antennas and the total number of UEs is kept fixed. The key design question is that what fraction of users should be offloaded to D2D mode in order to maximize the aggregate...
We considered a multi-user MIMO broadcast (BC) system with multiple antennas at both transmitter and receiver sides. A scheduling scheme using semi-orthogonal user selection (SUS) with zero-forcing beamforming (ZFBF) is implemented. The total feedback load required in ZFBF systems is reduced by implementing a two stage feedback scheme by restricting the number of users to participate in each stage...
This paper investigates the joint design of pilot assignment and pilot contamination precoding (PCP) to combat pilot contamination in multi-cell multi-user massive MIMO systems. The system performance of the downlink transmission in massive MIMO with PCP is investigated and an optimization problem is formulated to find the best pilot assignment solution in PCP assisted massive MIMO systems that can...
With the growing demand for mobile multimedia services in marine activities, maritime communication systems are impelled to provide higher data rates with limited radio resources. Massive multiple-input multiple-output (MIMO) is thus recognized as a promising technology in this case. However, pilot contamination leads to strong inter-cell interference and greatly degrades system performance. In this...
This paper investigates the multi-user full-duplex massive multiple-input multiple-output (MIMO) amplify-and-forward (AF) relaying system with low-resolution analog-to-digital converts (ADCs), where the zero-forcing transmitting/ zero-forcing receiving (ZFT/ ZFR) precoding scheme is employed. By modeling the loop-interference and quantization noise as additive noise, we perform the analysis of the...
Multiple-input multiple-output (MIMO) multi-carrier code division multiple access (MC-CDMA) wireless systems are sensitive to multi-user interference (MUI), which increases with increase in the number of users. In order to study its effect, pilot based linear channel estimators are derived considering also the effect of MUI in frequency-selective MIMO MC-CDMA wireless systems. The proposed schemes...
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