USE OF ADAPTIVE ANTENNA ARRAYS FOR INCREASE THE THROUGHPUT IN LTE-A

Context. The aim of the article is to analyze the throughput of the LTE-A mobile network on the uplink using an adaptive linear equidistant antenna array. Objective. Suggestions have been made for the possibility of using adaptive antenna arrays to increase bandwidth in LTE-A mobile networks and analyze the benefits of its use compared to the standard type of base station antenna Method. To achieve this result, a computer model of noise analysis of the mobile network in the form of a flat regular hexagonal antenna array consisting of 7 three-sector cells was developed. To estimate the benefit from the use of adaptive antenna arrays, two options were analyzed: when using a standard antenna array of the LTE-A network, and an adaptive linear equidistant antenna array. During the simulation, 100 random placements of subscribers of useful and interference signals were performed and the minimum, maximum and average gain from the use of adaptive antenna arrays was calculated. The average value of the gain for the adaptive antenna array in the direction of the subscriber station, which generates a useful signal of 5.69 dB more than the standard antenna array of the LTE-A network. At the same time, there is a significant reduction in the gain of the adaptive antenna in the direction of the interference subscriber stations, namely, for those with the highest interference level, the gain is 32.84 dB and 28.33 dB, respectively. To clearly show the gain in the qualitative characteristics of the network, a bandwidth analysis was performed for different types of antennas. The bandwidth distribution (transport block size) for 50 resource blocks using an adaptive equidistant linear antenna array compared to a standard antenna array is presented. Results. It is shown that due to the use of adaptive antenna systems, the average bandwidth increases from 11 Mbit/s to 35 Mbit / s for all types of distribution considered channels. Conclusions. The article proposes the use of adaptive antenna arrays to increase the bandwidth of the LTE-A network. The simulation of bandwidth for 50 resource blocks showed that in the presence of internal system interference when using standard antennas of base stations, the average bandwidth is from 11.2 Mbps to 12.3 Mbps. At the same time, due to the use of adaptive antenna systems, the average bandwidth increases from 11 Mbit/s to 35 Mbit/s for all types of multipath channels considered.

HANDOVER ALGORITHM OF THE MCWILL SYSTEM IN THE MODE OF RADIO CHANNEL RESOURCE ALLOCATION CONFLICT ELIMINATION

Рассмотрен режим хэндовера системы МАКВИЛ, предназначенный для устранения конфликтов распределения ресурсов радиоканала и ориентированный на пространственную селекцию радиосигналов абонентов соседних базовых станций (БС), осуществляемую 8-элементными адаптивными антенными решетками (ААР). Представлен алгоритм управления ААР БС, направленный на ликвидацию конфликтов при максимальных нагрузках. Приведено описание алгоритма пространственной селекции, ориентированного на условия возможного отсутствия трасс прямой видимости и, как следствие, произвольных законов амплитудно-фазовых распределений полей на антеннах. Установлена численная связь между энергетическим запасом на краях зон обслуживания и эквивалентным угловым расстоянием между абонентами, достаточным для бесконфликтного пространственного разделения одинаковых спектрально-временных ресурсов. Показано, что ввод управляемого параметра задержки в режиме синхронизации позволит реализовать в МАКВИЛ пространственное разделение абонентов, обслуживаемых одной БС. The McWiLL system handover mode, designed to eliminate conflicts in the distribution of radio channel resources, focused on the spatial selection of radio signals of subscribers of neighboring base stations, carried out by 8-element adaptive antenna arrays, is considered. An algorithm for controlling the adaptive antenna arrays of base stations, focused on eliminating conflicts at maximum loads, is described. The description of the spatial selection algorithm, focused on conditions of the possible absence of line-of-sight traces and, as a result, arbitrary laws of the amplitude-phase distributions of the fields on antennas, is given. A numerical relationship is established between the energy reserve at the edges of the service areas and the equivalent angular distance between subscribers, sufficient for conflict-free spatial separation of identical spectral-time resources. It is shown that the input of a controlled delay parameter in the synchronization mode will allow the implementation of spatial separation of subscribers served by a single base station in the McWiLL system.

Signal processing by adaptive antenna arrays

This article outlines the basic theory of adaptive antenna arrays. The basic elements of an adaptive antenna array such as a diagramforming device and an adaptive processor are presented. The task of the adaptive processor is to control the diagram forming device, which provides the required processing of the input observation based on the available a priori information on the signal-interference environment. When such information is insufficient, the adaptive processor must have the ability to automatically adjust to the receiving conditions. In other words, the adaptive processor must implement some adaptation algorithm based on the initial data bank and the signal processing efficiency criterion. To quantitatively evaluate the performance of adaptive antenna arrays when receiving a useful signal, one of the ways of quality indicator has been considered: the RMS value of the deviation of the useful signal from the reference.

Помехоустойчивость трехэлементной адаптивнойантенной решетки в многолучевых каналахрадиосвязи ДКМВ-диапазона

Using the modified Watterson model of the radio channel the spatial signal processing (SSP) features of two- and three-element adaptive antenna arrays in thenonstationary multi-path HF channels are investigated. It is shown that the addition of a third antenna element significantly enhances the SSP efficiency of the multipathHF signals in comparison with two-element SSP. Исследованы особенности пространственной обработки сигналов (ПОС) в двух- и трехэлементных антенных решетках в нестационарных многолучевых ДКМВ каналах радиосвязи. Показано, что добавление третьего антенного элемента существенно повышает эффективность ПОС по сравнению с минимально необходимыми двумя ветвями разнесения пространственной обработки.

Integral indicator of adjustment parameters estimation of adaptive antenna arrays for telecommunication networks of information systems

Adjustment speed is one of the main operation features of adaptive antenna arrays with the steepest descent gradient algorithm in telecommunication networks of information systems. Traditionally, estimation of the transient processes involves a computer simulation of the adaptive antenna array according to the selected noise environment. Substantial time required to create a respective model, big computational load that leads to quite a long period of time for performing required mathematical operations, as well as limited possibilities of simulation results interpretations are among the main drawbacks of the traditional approach. The paper proposes an integral indicator of adjustment parameters estimation of adaptive antenna arrays optimized according to the root-mean-square criterion and that does not require performing of the time consuming computer simulation of the transient processes. Integral indicator assumes values from 1, which corresponds to the quickest adaptation process, to 0, which indicates an absence of adaptation, and is built with account of the eigenvalues distribution of the array correlation matrix, squares of direction cosines of the optimal weight vector on the eigenvalues of the antenna array correlation matrix and the trace of this matrix. Computer simulation helped to establish that the designed indicator permits to correctly predict the speed of the transient processes in adaptive antenna arrays and perform their comparative analysis for different noise environments. Additionally, computation data, which are used for obtaining this indicator, allow us to clearly explain the character of the transient processes in the adaptive antenna arrays.

Effect of Polarization on the Performance of Adaptive Antenna Arrays

The polarized electromagnetic waves impinging on adaptive antenna arrays have significant impact on their performance. In this paper we investigate the effect of polarized desired and undesired signals on the performance of electronically steered beam adaptive antenna arrays in terms of their output SINR’s (Signal to Interference plus Noise Ratios). To achieve this goal, we compare the performances of adaptive antenna arrays composed of single dipole antenna elements with those composed of cross-dipole antenna elements to illustrate the effect of polarized signals on their performance. Based on the experimental and simulation results, it will be shown that the adaptive antenna arrays using cross-dipole antennas provide better performance compared to those using single-dipoles, in presence of randomly polarized signals. However, if the desired signal polarization is well known, single-dipole antenna arrays exhibit better performance.