In spatial spectrum estimation field, medium-scale or large-scale receive antenna array with digital beamforming can be employed at receiver to achieve a high-resolution direction of arrival (DOA) estimation and make a significant interference suppression, but leads to an expensive RF-chain circuit cost. Thus, a robust hybrid analog-and-digital beamforming (ADB) structure is proposed to greatly...

This document contains a first assessment of spatial transmission schemes regarding performance and complexity. In order to assess advanced beamforming and MIMO technologies, mathematical models, as well as methodologies for simulation and assessment have been developed. Conceptual work and simulation campaigns have been conducted. A baseline WINNER multi-antenna concept is proposed for further...

In multi-user beamforming systems, the inter-user interference are controlled by spatial filtering. Since the implementation of digital beamforming is difficult due to high hardware cost of large array system, the analog beamforming system with one phase shifter at each antenna element is considered with antenna selection scheme. However, the beamwidth is not sufficiently narrow to perfectly re...

In this paper, we investigate broadband OFDM systems which apply beamforming in combination with different space–time diversity techniques. Various beamforming scenarios with transmitter and/or receiver sided beamforming are considered. Space–time diversity is obtained by cyclic delay diversity (CDD) in order to artificially shape the spectrum of the received signal. Thus, an advantageous distr...

Millimeter wave (mmWave) spectrum has drawn attention due to its tremendous available bandwidth. The high propagation losses in the mmWave bands necessitate beamforming with a large number of antennas. Traditionally each antenna is paired with a high-speed analog-to-digital converter (ADC), which results in high power consumption. A hybrid beamforming architecture and one-bit resolution ADCs ha...

In smart antenna applications, the adaptive beamforming technique is used to cancel interfering signals (placing nulls) and produce or steer a strong beam toward the target signal according to the calculated weight vectors. Minimum variance distortionless response (MVDR) beamforming is capable of determining the weight vectors for beam steering; however, its nulling level on the interference so...

In this presentation, we study the applications of robust optimization in signal processing: robust beamforming in array and power control in wireless networks. First, the background of beamforming and the traditional diagonal loading (DL) method are introduced. Then, the robust beamforming designs are proposed by considering the worst-case distortionless and probabilistic constraints of the st...

In this paper, several multiple-input multiple-output (MIMO) techniques are studied for OFDM/A systems which have antennas connected to the base station with radio over fiber (RoF). The delay effects caused by the optical fibers on the fixed-beam transmit beamforming are studied via Monte Carlo simulations. Also the effect of combining RoF with other MIMO techniques in OFDM/A systems, like spat...

3D beamforming is a promising approach for interference coordination in cellular networks which brings significant improvements in comparison with conventional 2D beamforming techniques. This paper investigates the problem of joint beamforming design and tilt angle adaptation of the BS antenna array for maximizing energy efficiency (EE) in downlink of multi-cell multi-user coordinated cellular ...

This paper investigates spectrum sharing issues in the unlicensed industrial, scientific, and medical (ISM) bands. It presents a radio frequency measurement setup and measurement results in 2.4 GHz. It then develops an analytical model to characterize the coexistence interference in the ISM bands, based on radio frequency measurement results in the 2.4 GHz. Outage performance using the interfer...