Ministry of higher and secondary special education of the republic of uzbekistan the ministry for development of information
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Manual Wireless networks
Base station service area
To begin with, it should be noted that there are different types of base stations: macro, micro, pico and femtocells. Let's start small. And, in short, the femtocell is not a base station. Rather, it is an Access Point. This equipment is initially aimed at home or office users and the owner of such equipment is a private or legal entity. a person not related to the operator. The main difference of such equipment is that it has a fully automatic configuration, starting from the assessment of radio parameters and ending with the connection to the operator's network. Femtocell has the dimensions of a home router: Fig.8.4. Access point element. Picocell is a low-power base station owned by the operator and using IP / Ethernet as a transport network. Usually installed in places of possible local concentration of users. The device is comparable in size to a small laptop: Microcell is an approximate implementation of a base station in a compact form, very common in operators' networks. It differs from the "big" base station by the reduced capacity of those supported by the subscriber and lower radiating power. The mass, as a rule, is up to 50 kg and the radius of the radio coverage is up to 5 km. Such a solution is used where high capacities and network capacities are not needed, or it is not possible to install a large station: 55 Fig. 8.5. Microcell antenna unit. And finally, a macrocell is a standard base station on the basis of which mobile networks are built. It is characterized by a power of about 50 W and a coverage radius of up to 100 km (in the limit). The rack weight can be up to 300 kg. The coverage area of each BS depends on the height of the antenna section, the terrain and the number of obstacles on the way to the subscriber. When installing a base station, the coverage radius is far from always in the foreground. As the subscriber base grows, the maximum BS bandwidth may not be enough, in which case the message "network busy" appears on the phone screen. Then the operator, over time, in this area can deliberately reduce the range of the base station and install several additional stations in places of greatest load. When you need to increase the network capacity and reduce the load on individual base stations, then microcells come to the rescue. In a megalopolis, the radio coverage area of one microcell can be only 500 meters. Fig.8.6. Macrocell Base station. 56 So, for example, in the range of 1800 MHz, the BS operating range does not exceed 6-7 kilometers, and in the case of using the 900 megahertz range, the coverage area can reach 32 kilometers, all other things being equal. In a city, oddly enough, there are places where the operator needs to locally connect a section with a large amount of traffic (metro station areas, large central streets, etc.). In this case, low-power microcells and picocells are used, the antenna units of which can be located on low buildings and on street lighting poles. When the question of organizing high-quality radio coverage inside closed buildings (shopping and business centers, hypermarkets, etc.) arises, then pico- cell base stations come to the rescue. Outside cities, the range of operation of individual base stations comes to the fore, so the installation of each base station at a distance from the city is becoming an increasingly expensive enterprise due to the need to build power lines, roads and towers in difficult climatic and technological conditions. To increase the coverage area, it is desirable to install the BS on higher masts, use directional sector emitters, and lower frequencies that are less susceptible to attenuation. Download 6.03 Mb. Do'stlaringiz bilan baham: |
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