Andrey Pudeyev

Quasi-deterministic approach to mmWave channel modeling in a non-stationary environment

There is increasing faith that mmWave technology will be part of 5G wireless networks in the wide frequency range 30-90 GHz. Experimental measurements are used to model mmWave channels addressing issues like human body shadowing or reflections due to moving vehicles. In this paper a new quasi-deterministic (Q-D) approach is introduced for modeling mmWave channels. The proposed channel model allows natural description of scenario-specific geometric properties, reflection attenuation and scattering, ray blockage and mobility effects. This new channel modeling approach is of utmost importance for further measurement campaigns planning, channel model characterization, system level simulations and network access capacity estimations.

Highly Directional Steerable Antennas: High-Gain Antennas Supporting User Mobility or Beam Switching for Reconfigurable Backhauling

Modern millimeter-wave (mmWave) communication systems for large indoor areas and most outdoor scenarios require high-gain antennas with beam-steering ability to support user mobility or beam switching for reconfigurable backhauling. In this article, two new concepts for the development of highly directional steerable mmWave antennas are proposed and analyzed. The first one is modular antenna array (MAA) technology, which allows the creation of large-aperture, high-gain adaptive antenna arrays in a cost-effective and scalable manner. Two MAA configurations based on the existing phased subarray module are considered and analyzed for mmWave small-cell access and backhauling. The second prospective technology that fulfills the required antenna parameters for mmWave smallcell flexible backhauling is the lens-array antenna (LAA). The combination of the dielectric lens for aperture increasing with only one subarray module with beam-steering capabilities may provide 25-30-dBi total antenna gain with azimuth sector sweeping ±45°.

Partially adaptive arrays application for MU-MIMO mode in a MmWave small cells

In this paper we provide detailed system level performance analysis of MU-MIMO mode in the millimeter wave (mmWave) small cells (Wi-Fi hotspots) environment. Traditional way of MIMO implementation assumes a single RF chain per antenna element, with all spatial processing done in the baseband. To overcome high pathloss in the mmWave bands, the large-aperture, very high gain arrays with a large number of elements (several hundreds) are required. Therefore we introduce partially adaptive arrays with reduced number of degrees of freedom which are implemented based on the modular antenna arrays (MAA) architecture. The scalable practical design of MAA allows creation of large-aperture, high-power antenna arrays with reduced number of RF chains at cost of decreasing the adaptability. Employing recently proposed quasi-deterministic (Q-D) model for millimeter-wave channels, it was shown that partially adaptive MAA have very small degradation in comparison with ideal fully adaptive array (FAA) in a realistic scenarios. It was shown that application of MU-MIMO mode in a mmWave small cells allows achieving up to 15-30 Gbps total throughput per cell in a multipath environment (university campus scenario) with practical antenna array design.

Analysis of IEEE 802.16m and 3GPP LTE Release 10 technologies by Russian Evaluation Group for IMT-Advanced

The IMT-Advanced standardization process is executed by International Telecommunications Union Radiocommunication Sector (ITU-R) to define requirements to the next 4-th generation mobile communication systems and certify technologies meeting these requirements. This work presents results of the IEEE 802.16m and 3GPP LTE Release 10 technologies evaluation obtained by the Russian Evaluation Group (REG) as part of the ITU-R IMT-Advanced standardization process. The evaluation was done mainly by system level simulations and considered four mandatory test environments of IMT-Advanced: indoor, microcellular, base coverage urban and high speed. Cell spectral efficiency and cell-edge user spectral efficiency were evaluated for downlink and uplink transmissions. It was found out that performance of both IEEE and 3GPP technologies meets the IMT-Advanced requirements for all the considered evaluation scenarios. This conclusion was conveyed by the REG to ITU in the evaluation report submitted in June 2010.

Proof-of-Concept of a Millimeter-Wave Integrated Heterogeneous Network for 5G Cellular

The fifth-generation mobile networks (5G) will not only enhance mobile broadband services, but also enable connectivity for a massive number of Internet-of-Things devices, such as wireless sensors, meters or actuators. Thus, 5G is expected to achieve a 1000-fold or more increase in capacity over 4G. The use of the millimeter-wave (mmWave) spectrum is a key enabler to allowing 5G to achieve such enhancement in capacity. To fully utilize the mmWave spectrum, 5G is expected to adopt a heterogeneous network (HetNet) architecture, wherein mmWave small cells are overlaid onto a conventional macro-cellular network. In the mmWave-integrated HetNet, splitting of the control plane (CP) and user plane (UP) will allow continuous connectivity and increase the capacity of the mmWave small cells. mmWave communication can be used not only for access linking, but also for wireless backhaul linking, which will facilitate the installation of mmWave small cells. In this study, a proof-of-concept (PoC) was conducted to demonstrate the practicality of a prototype mmWave-integrated HetNet, using mmWave technologies for both backhaul and access.

Backhaul network based on WiMAX with relays - system level performance analysis

In this paper we present the system level performance analysis of the backhaul network based on WiMAX (IEEE 802.16-2004, 2004) with relays. The considered wireless communication system has hexagonal cellular structure, each cell containing a central base station (BS), one or more associated relay stations (RS), all serving the plurality of subscriber stations (SS). The base stations and the relay stations may share the same time-frequency resources when serving subscribers in accordance with various relaying modes having different reuse factor and leading to different level of interference in the deployment. The performance analysis of different relaying modes is presented in this paper. The methodology of individual mode assignment for each subscriber and frame composition is presented along with the analysis of geographical distributions of subscriberspsila preferable relaying modes. Finally, the total cell throughput is evaluated for the case of optimal subscriberspsila assignment to different relaying modes. We show that suggested adaptive relaying technique gives significant increase in the total cell throughput and spectral efficiency.

Multi-user frequency domain scheduling for WiMAX OFDMA

This paper introduces the performance analysis of 802.16e OFDMA system in UL mode with respect to multi-user scheduling algorithms in frequency domain. Different scheduling algorithms - from the simplest round robin to the optimal iterative scheduling along with practical maximum element and two-step algorithms are analyzed and compared. It is shown that multi-user scheduling in frequency domain potentially can greatly improve OFDMA system efficiency in frequency-selective broadband channel.

Practical LOS MIMO Technique for Short-Range Millimeter-Wave Systems

The widespread availability and use of digital multimedia content has created a need for faster wireless connectivity that current commercial standards cannot support. For example, new generation of display and input-output (IO) interfaces require data rates well in excess of 10 Gbps. The large amount of spectrum in the unlicensed 60 GHz millimeter-wave (mmWave) band offers the most promising approach to meet this challenge, but existing standards operating in this band are limited to data rates below 7 Gbps. Therefore, in this paper we propose a practical mmWave technique that combines the benefits of multi-input, multi-output (MIMO) transmissions and a line-of-sight (LOS) communication channel, hereby referred to as LOS MIMO. Different implementations for LOS MIMO using various options for stream separation techniques including separation in the radio front-end (RF), in the baseband, or by polarization are also discussed. The performance of these LOS MIMO implementations is evaluated by simulations. We show that LOS MIMO systems based on low-power phased antenna arrays can operate at the distances up to several meters and achieve data rates above ten Gbps, thus meeting the requirement of the new generation high-speed interfaces.

Performance evaluation of interference mitigation techniques in the overlaying MmWave small cell network

In this paper we consider heterogeneous cellular network with a number of millimeter-wave (mmWave) small cells overlaying LTE macro cells. The impact of mutual interference in millimeter-wave band (57-64 GHz) is addressed and evaluated. We introduce several active interference cancellation techniques which are implemented at TX sides of mmWave small cell BSs equipped with adaptive antenna arrays. We started from the task of multi-stream intra-cell interference suppression in MU-MIMO mode by means of well-known Zero-Forcing (ZF) algorithm. Then more complex schemes involving coordinated multi-point (CoMP) operation of several neighboring BSs with Coordinated Scheduling (CS) and Coordinated Beamforming (CB) are investigated. Finally, performance evaluation and comprehensive comparative analysis are done by simulations for different mmWave small cell sizes and densification. Presented results allow to establish lower and upper bounds of interference impact and make reasonable selection of the suitable interference mitigation technique for mmWave overlaying network.

Virtual Antenna Array Methodology for Outdoor Millimeter-Wave Channel Measurements

The development of new outdoor millimeter-wave channel models requires processing of the experimental data which can be used to estimate multipath channel parameters with very high time and angular resolution. The virtual antenna arrays processing technique allows joint narrow beam forming and beam steering. The specific of outdoor experiment does not allow precise positioning of the antennas, like it possible under lab-conditions. So some special methodology should be developed to overcome this problem. In this paper we propose the virtual antenna array signal processing which allows for given experi-mental data to perform environment scanning with equivalent 1° antenna beamwidth and -30dB sidelobes rejection. As a result, the measurement environment was accurately reconstructed on the base of measurement data. High angular resolution of the proposed virtual antenna array signal processing allows estimat-ing the wall-reflected rays (channel clusters) power-angular spectrum parameters for a Laplacian model.