Modelling the energy efficiency of microcell base stations

The power consumption of wireless access networks will become a major issue in the coming years. Therefore, it is important to have a realistic idea about the power consumption of each element in those access networks. In this paper, an energy efficiency model for microcell base stations is proposed. Based on this model, the energy efficiency of microcell base stations is compared for various wireless technologies, namely mobile WiMAX, HSPA and LTE. The power consumption of microcell base stations is about 70-77% lower than for macrocell base stations but a macrocell base station is more energy-efficient than a microcell base station for the same bit rates. However, for the considered case and assuming our parameters are correct, a reduction in power consumption can be obtained by using microcell base stations to fill coverage holes

Model for power consumption of wireless access networks

The power consumption of wireless access networks will become an important issue in the coming years. In this study, the power consumption of base stations for mobile WiMAX (Worldwide Interoperability for Microwave Access), fixed WiMAX, UMTS (Universal Mobile Telecommunications System), HSPA (High-Speed Packet Access) and LTE (Long-Term Evolution) is modelled and related to the coverage. A new metric, the power consumption per covered area PC(area), is introduced, to compare the energy efficiency of the considered technologies for a basic reference configuration and a future extended configuration, which makes use of novel Multiple Input Multiple Output (MIMO) technology. The introduction of MIMO has a positive influence on the energy efficiency: for example, for a 4 x 4 MIMO system, PC(area) decreases with 63% for mobile WiMAX and with 50% for HSPA and LTE, compared to a Single Input Single Ouptut (SISO) system. However, a higher MIMO array size (i.e. a higher number of transmitting and receiving antennas) does not always result in a higher energy efficiency gain

A review on electromagnetics (EM) exposure measurement techniques from base station

EM exposure in the range of non-ionizing radiations (NIR) which falls in the radio frequency up to 3GHz is mainly sourced from mobile phone base stations, broadcast towers and radar facilities. This reviews based on previous researcher obtained results and methods in order to determine the best technique to measure the exposure. Moreover, the estimation of exposure levels by considering the specification of the antennas installed and area of the base stations itself was also reviewed. It was found that numerous study of NIR exposure level has been conducted in other countries, while Malaysia has become aware of the importance. Most of the studies used field meter to carry out the measurement, and the exposure level obtained were far lower than the limit recommended by World Health Organization (WHO).Keywords: electromagnetic exposure level, base station, electric field strength, geographical information syste

Assessment of multipath and shadowing effects on UHF band in built-up environments

Ultra-high frequency (UHF) bands are radio frequencies in the range of 300 MHz and 3 GHz. These bands are used for television broadcasting, mobile cellular systems, Wi-Fi, satellite communications and many others. Effective communication link in the UHF band requires direct line of sight between the transmitters and receivers. However, this is not always the case in built-up areas where diverse obstacles such as large buildings, trees, moving objects and hills are present along the communication path. These obstacles result in signal degradation as a result of shadowing (blockages) and multi-path, which are two major causes of signal losses. Path loss models are used in predicting signal losses but, the accuracy of these models depend on the fitness between the model's predictions and measured loses. In this work, the multi-path and shadowing effects on signal impairment were investigated through the use of empirical and semi-empirical path loss models analysis in built-up environments. Electromagnetic field strength measurements were conducted using four television transmitters at UHF bands along four major routes of Osun State, Nigeria. Experimental and simulation results indicated that the empirical models provide a better fit than the semi-empirical models. It was also found that the poor performance of the Knife Edge Model which is a semi-empirical model was traced to the bases of its formulation, which assumed point like knife edge for all obstacles on the path of radio propagation. The work therefore recommends that network planners employ empirical models found suitable for their kind of terrain when faced with coverage planning and optimization.Keywords: Path loss models, Radio propagation,  Terrain feature

Directive mmWave radio channel modeling in a ship hull

Wireless connectivity has been realized for multiple environments and different frequency bands. However, little research exists about mmWave communication in industrial environments. This paper presents the 60 GHz double-directional radio channel for mmWave communication in a ship hull for Line-of-Sight (LOS) and non-Line-of-Sight (NLOS) conditions. We performed channel measurements using the Terragraph channel sounder at different locations in the ship hull and fitted LOS path loss to a one-slope path loss model. Path loss and root-mean-square delay spread of the LOS path is compared to the reflected path with lowest path loss. NLOS communication via this first-order reflected path is modeled by calculating the path distance and determining the reflection loss. The reflection losses have a considerable contribution to the signal attenuation of the reflected path. The channel models are implemented in an indoor coverage prediction tool, which was extended with a ray launching algorithm and validated by comparison with an analytical electromagnetic solver. The results show that the mmWave radio channel allows high-throughput communication within a ship hull compartment, even when no LOS path between the transmitter and receiver is present.This work was executed within the Internet-of-Shipping (IoS) research project, co-financed by imec with support from Flanders Innovation & Entrepreneurship. The channel sounder has been granted as part of the Channel Sounder Program of the Telecom Infra Project (TIP). The authors would like to thank Ivan Renette and Franck Ntibashirakandi from Exmar Shipmanagement to facilitate the measurement campaign.Peer ReviewedPostprint (author's final draft

Comparison of the link budget with experimental performance of a WiMAX system

The performance of different modulation schemes of a broadband fixed wireless 802.16 (WiMAX) system in a sector is experimentally determined and compared to link budget calculations using different path loss models. A link budget based on path loss measurements of the actual WiMAX signal at 3.5GHz for a typical residential scenario in a suburban environment is determined. The link budget calculations show a reasonable agreement with actual performance measurements with certified WiMAX modems. Carefulness is advised when these models are used for the actual deployment of aWiMAX network in a specific area