Base Station Antenna Configuration Research Articles

Analysis of Massive Multiple Antenna System Capacity based on Channel State Information Performance

This paper has simulated channel capacity with respect to information transmitted without and with channel state information (CSI) in multiuser massive multiple input multiple output (MU massive MIMO) for downlink wireless communication. The objective was to examine the effect of CSI at the transmitter on the channel capacity. Simulations were conducted considering different base station antenna configurations transmitting signals to multiple users’ terminals over Rayleigh channels at signal to noise ratio (SNR) of 0 to 25. Two scenarios were considered namely, channel capacity of uninformed transmitter (that is without channel state in information known at the transmitter) and channel capacity of informed transmitter (with channel state information known at the transmitter). Power allocation among the transmit antennas was done using the water filling algorithm. The results of the simulations conducted revealed that the capacity of the system was improved when the transmitter was aware of the CSI. Also, increased number of receive antennas (UEs) was observed to compensate for lack in channel knowledge. Furthermore, increasing the number of base station antennas resulted in more channel capacity.

Multi-Panel Sparse Base Station Design With Physical Antenna Effects in Massive MU-MIMO

A novel base station antenna (BSA) configuration is presented to mitigate degrading physical antenna effects in massive multiple-input multiple-output (MIMO) systems, while minimizing implementation complexities. Instead of using a commonly considered single antenna panel comprising of many elements covering a wide field-of-view (FOV) of 120 degrees, L tilted panels are used employing L times fewer elements and L times smaller FOV per panel. The spatial resolution of each panel is enhanced by employing sparse arrays with suppressed (grating-lobe) radiation outside its corresponding FOV. Therefore, more directive antenna elements can be deployed in each panel to compensate for the effective isotropic radiated power (EIRP) reduction. While sectorisation reduces the antenna gain variation in 120 degrees FOV, cooperation among multiple panels in downlink beamforming is seen to be capable of inter-panel interference suppression for sum-rate enhancement. A network model is used as a multi-user (MU) MIMO simulator incorporating both antenna and channel effects. It is shown that when the number of base station antennas is ten times the number of users, the average downlink sum-rate in pure line-of-sight (LOS), rich and poor multipath environments is increased up to 60.2%, 23% and 11.1%, respectively, by multi-panel sparse arrays applying zero-forcing (ZF) precoding.

Performance Comparison of Alternative Indoor 5G Micro-Operator Deployments in 3.6-GHz and 26-GHz Bands

The fifth generation (5G) networks will provide local high-quality wireless services, especially within indoor areas. New local 5G network operator models, such as the recently introduced micro-operators, are increasingly important for vertical specific service delivery. The emergence of 5G micro-operator networks in spatially confined areas depends on local spectrum availability. In this paper, we investigate the performance of local 5G indoor micro-operator networks in the 3.6-GHz and 26-GHz bands. We consider two uncoordinated time-division duplex networks in adjacent buildings sharing the same channel with different base station antenna configurations and deployment densities. We evaluate the resulting performance of the victim network via system simulations. We have observed that the center frequency does not significantly impact the downlink performance unless the network is noise-limited. However, the uplink performance in 26-GHz band is affected by higher coupling losses between the base stations and mobile terminals. Our results indicate that beamforming and wider bandwidths help to improve the performance in 26-GHz band. More importantly, two indoor micro-operators can successfully coexist with a very small separation distance in the 26-GHz band, while in the 3.6-GHz band, a considerably larger isolation between the networks is required, for example, in the form of a much larger separation distance.

Design of Experiments to Compare Base Station Antenna Configurations

Publishing measurement results without elaborating on the uncertainty included is a common practice in the wireless community. Therefore, it is not surprising that the application of state-of-the-art variance reduction techniques to wireless research is rarely seen. In this paper, we discuss, exemplarily, the benchmarking of the average link capacity of a 4×4 multipleinput multiple-output (MIMO) downlink resulting from different base station (BS) antenna configurations. We show that the capacity of this downlink is not only dependent on the antenna spacing (the effect we want to measure), but also on the position of the antennas (an effect we need to control for). Unfortunately, once we change the antenna spacing, we cannot avoid changing the position of the antennas as well. We show that by applying the variance reduction technique of randomizing BS antenna positions, we get more accurate results. We further show that without increasing the effort, our favored method of matching completely eliminates the systematic error of position dependence. Both methodologies can also be applied to throughput measurements and larger antenna arrays, especially to virtual antenna array measurements for massive MIMO.

Impact of Base Station Site, Antenna Configuration and Power Control in LTE Network

This study analyzed the impact of spatial distribution of APs/Base stations, antenna configuration and power control in a dense populated area like Owerri (Nigeria), using link planner network simulator and Google-Earth Software. High-effective data capacity at hotspots in conjunction with bandwidth and the predicted power at the receiver for LTE network are required to capture some number of users and provide high data rates over the Wi-Fi interface. The data rates are influenced by the terrain, which loses throughput due to delays, path loss and interference. The hotspot range which determines the number of users, that can associate, is limited by the power of the client and the access point. The variables that affect link performance, such as: band, region, equipment, antenna, height, terrain and obstructions towards providing enhanced capacity and coverage are measured by the link planner. The characteristics like gain, beam, width and frequency, for evaluation of results in terms of coverage and capacity for different antenna configurations, receive-Power, terrain, bandwidth and distances are also observed respectively. The results show that pathloss increases or decreases with these factors between nodes. The strategy to place the transmitter in the highest position has also proven better performance for implementation of the LTE system and its long run operation.

A cellular base station antenna configuration for variable coverage

The field coverage offered by the base station antenna in GSM systems influences the reception and interference performances. The coverage can be varied by scanning the mainbeam direction or varying the shape of the radiation pattern. In cellular system applications, a simple technique is desirable to achieve this goal. A simple technique to vary the coverage of cellular base station is investigated. The technique uses two conventional antennas tilted by a certain angle and fed by the same signal but at variable amplitudes. It is demonstrated that the field across one half of the covered sector can be gradually increased while that at the other half is reduced by varying the excitations of the two antenna elements. This can be deployed in a simple electronic means in response to the changing scenario rather readjusting the direction of the base station antenna.

Spatial spectral and energy efficiencies of cellular networks limited by co-channel interference and path loss in Nakagami-m fading environment

A comprehensive framework for design of hexagonal cellular network system in terms of spatial spectral and energy efficiencies is presented. The communication environment in the system is assumed to be Nakagami-m fading coupled with simplified path loss model and co-channel interference. Three base station antenna configurations namely, omni, 120° and 60° are considered. Closed-form expressions for spatial spectral and energy efficiencies and coverage probability are derived and illustrated as a function of signal-to-noise ratio, cell radius, reuse distance, path loss exponent factor, and fading figure. A discussion of trade-offs among spatial spectral efficiency, spatial energy efficiency, and coverage probability as a function of parameters of cellular system and propagation environment is also provided. Numerical results show that the use of sectorized antenna system in the cellular network provides significant improvements even under severe propagation and interference conditions. For example, it is observed that the 120° base station antenna configuration system provides nearly double the spatial energy efficiency relative to the omni configuration system.

An Enhanced Difference Method for Multi-objective Model of Cellular Base Station Antenna Configurations

In this paper, we propose a fine-grained grid-based multi-objective model which aims at optimizing base station antennas' configurations, such as transmit power, antenna tilt and antenna azimuth, in order to upgrading network performance in cellular networks. As the model is non-convex, non-smooth and discrete and computationally expensive, we use decomposition method to solve the MOP problem. We mainly focus on addressing the scalarized sub-problem after decomposition. For the scalarized sub-problem, we propose an enhanced difference method. First, difference of each component is calculated, which provides the guidance of optimization. Then an OPSO is applied to search the optimal step length. The method is applied to GSM network optimization on an area in Beijing. The effect of the application shows that proposed method has a good performance, and is effective/efficient to solve mobile network optimization problems.

Automated optimization of service coverage and base station antenna configuration in UMTS networks

Deployment and maintenance of UMTS networks involve optimizing a number of network configuration parameters in order to meet various service and performance requirements. In this article we address automated optimization of service coverage and radio base station antenna configuration. We consider three key configuration parameters: transmit power of the common pilot channel (CPICH), antenna tilt, and antenna azimuth. CPICH power greatly influences coverage. From a resource management point of view, satisfying the coverage requirement using minimum CPICH power offers several performance advantages. In particular, less CPICH power leads to less interference and higher system capacity. Optimal CPICH power, in its turn, is highly dependent on how the other two parameters, tilt and azimuth, are configured at radio base station antennas. Optimizing antenna tilt and azimuth network-wise, with the objective of minimizing the CPICH power consumption, is a challenging task. The solution approach in this article adopts automated optimization. Our optimization engine is a simulated annealing algorithm. Staring from an initial configuration, the algorithm searches effectively in the solution space of possible configurations in order to find improvements. The algorithm is computationally efficient; thus, we can optimize large networks without using excessive computing resources. We present a case study for a UMTS planning scenario in Lisbon. For this network, automated optimization saves up to 70 percent of the CPICH power used in the reference network configuration. In addition, the optimized network configuration offers significant performance improvement in terms of fewer overloaded cells and lower downlink load factor

Radio propagation characteristics in curved tunnels

Radio propagation in curved tunnels of rectangular or arched cross-sections is modelled. The base station and tunnel parameters which have a significant influence on the propagation slope in curved tunnels are determined. The impact of these parameters on the propagation is then analysed and an optimum set of values is determined. Results are based on computed simulations utilising a ray launching approach with the Monte Carlo method. The obtained results show that the radio propagation slope depends on several practical planning parameters including the incident angle of the arrival signal, wall roughness, antenna location and antenna polarisation; especially in connection with tunnel shape. According to the results, antenna location and polarisation have a significant influence on the reflection angle, on reflection coefficient values, and thus on radio propagation. It is also shown that a tunnel cross-section size has only a minor effect on the propagation slope. Hence, the base station antenna configuration and the mobile antenna inclination have a superior impact on optimised coverage in curved tunnels.

Antenna systems for base station diversity in urban small and micro cells

The authors describe cross-correlation properties for compact urban base station antenna configurations, nearly all of which result in very low envelope cross-correlation coefficients of about 0.1 to 0.3. Specifically, polarization diversity systems are examined for their potential in improving link quality when hand-held terminals are involved. An expression is given for the correlation function of compound space and polarization diversity systems. Dispersion and envelope dynamic statistics are presented for the measured environments. For microcell applications, it is found that systems such as GSM having a bandwidth of 200 kHz or less can use narrowband cross-correlation analysis directly.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>