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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...
Closed-form approximations to the expected perterminal signal-to-interference-plus-noise-ratio (SINR) and ergodic sum spectral efficiency of a large multiuser multiple-input multiple-output system are presented. Our analysis assumes correlated Ricean fading with maximum ratio combining on the uplink, where the base station (BS) is equipped with a uniform linear array (ULA) with physical size restrictions...
In Virtual Antenna Array (VAA) based wireless system, knowledge of users' locations can help the transmitter to achieve interference avoidance by steering the main beam towards the intended recipient. In this work, the idea has been applied to licensed shared access (LSA) based cognitive radio (CR) environment where location aware beam-forming has been implemented on spatially modulated Generalized...
This paper investigates the feasibility of a radio access system with a self-backhauling access node under full-duplex and half-duplex operation modes. In particular, after making certain simplifying assumptions, closed-form solutions for the feasibility conditions of such a radio access system are derived for both of the considered operation modes. Furthermore, the analysis incorporates given quality...
Joint power control with optimal beamforming design and power control with minimum antenna selection under signal to inference noise ratio constraints have been considered in separate wireless communication scenarios. In power control algorithms, multiple antennas with linear beamforming are used to reduce the interference power, which also minimizes the total transmitted power in uplink/downlink...
Next-generation wireless networks are expected to support exponentially increasing number of users and demands of data, which all rely on the essential media: spectrum. Notice that the 5G networks are featured either by wide bandwidth like mmWave systems, or by large-scale antennas like massive MIMO. We find those two trends, together with waveforming or beamforming, can lead to a common phenomenon:...
In the present paper we evaluate the performance of a hybrid digital/analog multi-beam beam-forming architecture with polarization and delay compensation using time reversal (TR). Double-directional, ultra wideband dual-polarized channel measurements at 70 GHz in a conference room have been used to emulate the channel. The use of multiple beams to mitigate human shadowing has been evaluated and the...
This paper studies the beamspace multiplexing for free-space wireless millimeter-wave (mm-wave) backhaul applications, which has never been investigated before. A system architecture of a dual-beam mm-wave link is established, and the synthesis approach for the system key parameters that enable the beamspace multiplexing is presented. Extensive simulations are performed and the obtained results show...
Two dimentional (2D) adaptive digital beamforming is one of the promising smart antenna technologies to meet the rapidly increasing demands for more capacity of satellite communication systems. However, the conventional 2D adaptive digital beamforming algorithms have the jitter and high sidelobe problems especially when the number of antenna elements is large. In this paper, a penalty function based...
The macro- and micro-diversity schemes for the W-CDMA base stations deployed with smart antennae are investigated and their performances in terms of the improvement in the received bit energy to interference PSD ratio are evaluated, where both the adaptive and fixed beam schemes are considered for smart antenna systems. The macro-diversity scheme is employed to compensate the decrease of antenna gain...
MICROWAVE beamforming (MBF) is advantageous over digital beamforming (DBF) in several regards [1]. First, due to a lower number of RF down-converters and analog to digital converters (ADC), MBF structures have lower size, weight and battery power consumption. Second, due to weighting and combining of signals in the analog domain and avoiding quantization errors, MBFs have higher dynamic and suppression...
In this paper, we discuss the inter-array decoupling technique suitable for MIMO full-duplex, which uses a combination of the end-fire antenna arrangement and eigen-beamforming. An experimental evaluation clarifies that the end-fire antenna arrangement contributes to the reduction of the inter-array coupling by 18.7 dB compared with the facing antenna arrangement, and that the small antenna aperture...
The high precision ranging using ultra wideband (UWB) requires mitigation of interference from other communication systems, in particular from narrowband interference (NBI). There have been many studies of adaptive notch filters (ANF) to cope with NBI at various frequencies. This paper proposes a novel adaptive NBI mitigation method which uses the direction of arrival as well as frequency selectivity...
This paper proposes a novel transmission technique for Inter-Cell Interference Cancelation (ICIC) in cellular networks. The new technique utilizes the Conjugate Gradient Method (CGM) for calculating the optimal weight vector for the transmitting antenna array system operating at a base station. The weight vector provides a maximum gain along the direction of a target mobile device and deep nulls to...
In this work, a cost-effective radio frequency (RF) beamforming array is used to orient and suppress directional interfering signals. With this frontend, both the multiple signal classification (MUSIC) algorithm used in direction-of-arrival (DOA) estimation and the optimizaoion based power inversion (PI) algorithm used to suppress the interfering signal can be significantly simplified. With a RF output,...
This paper considers a multi-way massive multiple-input multiple-output (MIMO) relaying system. The bearing-information is exchanged among multiple users with the help of a multiple-antenna relay (the base station). The maximum-ratio (MR) processing is applied at the relay under the assumption of perfect channel state information. The spectral efficiency and the asymptotic results for the signal-to-interference-plus-noise...
The key indicators of analog to digital converter (ADC) are effective number of bits (ENOB) and spurious-free dynamic range (SFDR). ENOB would affect the input signal to noise ratio (SNR), and SFDR indicates the degree of spurious introduced by non-linear. The characteristics of multi ADC in antenna array would not be the same, which make the quantization noise introduced by ENOB and spurious indicated...
Channel mismatch has become a serious limit to further improve the anti-jamming performance on satellite navigation antenna arrays receivers. Consistency degree of each channel could directly determine the anti-jamming performance. In order to analyze and confirm the channel consistency indexes, this paper analyzes the impact of channel mismatch on interference cancellation ratio (ICR), firstly. According...
The nested array, which is implemented by nonuniform antenna placement, is an effective approach to achieve O(N^2) degrees of freedom (DoF) with an antenna array of N antennas. Such DoF refers to the number of directions of incoming signals that can be resolved. With the increased number of DoF, an important application of nested array is to nullify the interference signals from multiple directions...
In this paper, we provide an analytical framework to analyze heterogeneous downlink mmWave cellular networks consisting of tiers of randomly located base stations (BSs) where each tier operates in a mmWave frequency band. Signal-to-interference-plus-noise ratio (SINR) coverage probability is derived for the entire network using tools from stochastic geometry. The distinguishing features of mmWave...
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