RU2423795C2 - Shipborne subsystem for cellular mobile communication - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: subsystem includes antenna-repeaters, a repeater, a controller, a transcoder, a mobile communication switching centre, post switching centres, inter-post cables, transceivers, intermediate frequency amplifiers, devices for interfacing with a post cable for intra-ship communication, signal conversion and filtration devices, power dividers, a base station antenna, band-pass filters, mixers and heterodynes.

EFFECT: wide field of use of cellular mobile communication systems by facilitating functioning thereof on-board ships and other mobile objects.

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Description

The present invention relates to the field of electro-radio engineering, and in particular to mobile cellular communication systems, and can be used in enterprises developing radio communication equipment installed on mobile objects, for example surface ships, submarines, civilian vessels, railway transport, etc.

The ship’s cellular mobile subsystem is designed to be installed on ships to provide crew members with mobile cellular services both with subscribers of their facility and with external subscribers located within the service area of the ship’s base station.

A typical cellular communication system consists of subscriber mobile radiotelephones and base station equipment, consisting of a base station antenna, a multi-channel transceiver, a base station controller, a transcoder and a mobile switching center that provides all the functions of controlling a communication network (see [1] Fig. 3.17, p. 122). In the system, communication between subscriber phones and base stations is carried out over the air. The working frequency range in the 2nd generation GSM digital communication system, the most common in Russia, is: 1710-1785 MHz for transmission from a subscriber to a base station and 1805-1880 MHz for transmission from a base station to a subscriber.

When installing cellular communication equipment on a ship, the antenna of the base station should be located on the upper deck, and subscribers (crew members) are in the deck of the ship. The degree of shielding of the ship's hull is at least 80 dB. At the same time, the radio channel between subscriber and base stations will not work due to excessive signal attenuation. Those. the use of conventional equipment of the cellular communication system on the ship will not provide subscribers with cellular communications.

Known systems for providing subscribers with cellular mobile communications in rooms shielded relative to the antennas of ground base stations with a thick layer of reinforced concrete and metal structures. Such premises include:

- Metro stations;

- high-rise buildings;

- buildings with reinforced concrete floors;

- underground garages and parking lots;

- warehouses and customs terminals;

- airports and railway stations;

- sports complexes, etc.

Such systems include base station equipment located in each shielded room (for example, at each metro station), and repeaters (repeaters), one antenna of which is located within the reach of the base station antenna, and the other antenna (or several other antennas) located in a shielded room within the reach of antennas of subscriber stations. The repeater is essentially an antenna amplifier that amplifies the signal up to 60 dB. An example of providing communication to subscribers in an underground garage using a repeater [2] is shown in FIG.

In the subway, antennas are used in the lobby, on escalators, on platforms to provide cellular communications to subscribers, and a radiating cable is used to provide communication in tunnels. The radiating cable is an ordinary wire, but it works like the antenna of the base station, allowing cell phones to catch the signal from the cable as reliably as on the surface. True, the installation and creation of such a system is still very expensive. Laying one radiating cable along the stage between two metro stations costs about the same as installing three or four base stations on the surface [3].

Closest to the claimed subsystem is the subsystem of cellular mobile communications in the metro, described in [3]. It is selected as a prototype. The cellular mobile subsystem in the metro located at each metro station includes base station equipment consisting of series-connected antennas of the base station, multi-channel transceiver, base station controller, transcoder and mobile switching center, and repeaters, antennas for communication with subscribers of which are located on escalators, platforms and subway tunnels, and the outputs of the repeaters are connected via high-speed wired communication channels to the base station controller.

The use of the prototype subsystem in each room of the ship is not possible for the following reasons:

1. The external antenna of the base station on the ship can be one, because the ship has a large number of other antennas that provide radio communications, radio navigation, radar, etc. At the same time, the equipment of the base stations located in each room of the ship should be connected by radio-frequency cables to a single external antenna. Laying of radio frequency cables from one outdoor antenna to all rooms on existing ships is impossible, because cabling is carried out at the initial stage of construction of the ship's hull. In addition, there are standards for the maximum length of the antenna cable, which, as a rule, should not exceed 10 ... 50 m. With such standards, the wiring of the radio frequency cable from one antenna to all rooms of the ship even at the stage of its construction is unacceptable.

2. The placement of base station equipment in each room of the ship is also problematic due to the limited size of the rooms in which numerous traditional equipment is located.

To organize cellular communication on the ship, one base station should be installed and special devices should be developed for delivering signals from subscribers located in all spaces of the ship to the input of the multi-channel transceiver of the base station.

The aim of the invention is to expand the scope of cellular mobile communication systems by providing the possibility of its functioning on ships and other mobile objects where subscribers are in shielded rooms relative to the antenna of the base station.

This goal is achieved by the fact that in the ship’s subsystem of cellular mobile communications, consisting of n subscriber (in the number of subscribers) radiotelephones with antennas and m repeater antennas located in each room of the facility and connected through the first power divider with a repeater, and base station equipment, placed in one of the premises of the ship and consisting of an antenna and series-connected multi-channel transceiver, controller, transcoder and switching center for mobile communications, an additional post was introduced new switching centers and connecting cables between the posts from the shipboard communication complex, as well as transceiver located in each room of the ship, the first intermediate frequency amplifier, the first device for interfacing with the post cable for shipbuilding communication, the first signal conversion and filtering device, the output of which is connected with the second input of the transceiver, as well as placed in the room where the base station equipment is located, in series the second power divider connected between the antenna of the base station and the multi-channel transceiver, the second transceiver, the second intermediate frequency amplifier, the second device for interfacing with the post cable of the intra-ship communication, the second signal conversion and filtering device, the output of which is connected to the second input of the second transceiver, while the second inputs of interface devices with a post cable of intra-ship communication are connected to the corresponding outputs of the post switching centers, and the outputs are connected by an inter-post cable from the intrabuilder complex, each conversion and filtering device consists of a series-connected first bandpass filter, a mixer, a second bandpass filter and an intermediate frequency amplifier, as well as a local oscillator, the output of which is connected to the second input of the mixer, and each transceiver consists of from the analogue part of a standard digital cordless telephone.

Each device for interfacing with a post cable of an intra-ship communication is two series-connected tees. The input of the first tee is connected to the output of the intermediate frequency amplifier, and the output of the second tee is connected to the input of the signal conversion and filtering device.

Figure 2 shows a block diagram of a ship subsystem of cellular mobile communications. It consists of the following elements:

1 - base station antenna.

2 - base station equipment.

3 - power divider.

4 - multi-channel base station transceiver.

5 - base station controller.

6 - transcoder.

7 - mobile switching center (CCPS).

8 - a fast switching center from the complex of shipboard communications (VKS).

9 - low-frequency inter-post cables from the VKS complex.

10 - subscriber radiotelephone.

11 - antenna repeaters.

12 - high frequency power divider.

13 - repeater (repeater).

14 and 18 - transceiver.

15 and 19 - intermediate frequency amplifier.

16 and 20 - a device for interfacing with a post cable of intra-ship communication.

17 and 21 are a conversion and filtering device.

Figure 3 shows a diagram of a conversion and filtering device. It consists of the following elements:

22 - the first band-pass filter.

23 - mixer.

24 - second band-pass filter.

25 - intermediate frequency amplifier.

26 - local oscillator.

The transceiver 14 and 18 is designed to convert the cellular signal from high frequency to intermediate in the receiving channel and from intermediate frequency to high frequency in the transmitting channel. Each transceiver is an analog part of a standard digital radiotelephone, the structural diagram of which is shown in Fig.3.50 p. 160 [1]. In this case, the first input of the transceiver is its antenna input, the second input of the transceiver is connected to the input of the mixer of the transmitting channel of the transceiver, and the output of the amplifier of the intermediate frequency of the receiving channel is the output of the transceiver.

Interpostal cables 9 from the intra-ship communication complex are used to transmit cellular signals at an intermediate frequency between the spaces of the ship. The block diagram of the placement of switching centers and the connections between them in ship posts and rooms is shown in Fig.8.5 p. 355 [5]. In accordance with this scheme, each post switching center is connected to all switching centers located in other spaces of the ship. Thus, all the spaces of the ship are connected using cables 9, which are low-frequency cables (for example, KNRT brand). Using these cables, it is proposed to transmit cellular signals at an intermediate frequency. The parameters of such a signal are as follows:

- signal modulation - spectrally effective Gaussian frequency shift keying with minimum frequency shift (GMSK);

- Gaussian filter bandwidth 80 kHz;

- 2nd intermediate receiver frequency of the order of 5 MHz.

The propagation of an intermediate frequency of the order of 5 MHz over a low-frequency cable will undergo attenuation. For a cable of the KNRT brand, the attenuation constant at a frequency of 5 MHz is 0.0115 n / m or 0.1 dB / m. With cable lengths between posts of 10 to 100 m, the signal attenuation will be 1 to 10 dB. To compensate for signal loss during propagation in the cable between the spaces of the ship, intermediate frequency amplifiers 15 and 19 with a gain of up to 20 dB are used.

High-frequency power divider 3 and 12 and repeater 13 are standard elements of the equipment for base stations [4].

Power dividers 3 and 12 are designed for power distribution between several antennas or between an antenna and a high-frequency cable. They can also be used to form branched cable networks both indoors and outdoors.

KATHREIN offers dividers for all required frequency ranges, for input power levels from units to 1000 watts. Models with equal division into 2/3/4 channels (splitter) and unequal division into 2 channels (tapper) with division losses of 6/10/15 dB are produced. The coaxial design and advanced manufacturing technology of these devices provide a level of intrinsic loss of not more than 0.05 dB.

Repeater 13 is a type of antenna amplifier, but unlike the latter, the repeater is “connected” to subscriber radiotelephones not by cable, but by radio channel. On the one hand, external antennas are connected or a high-frequency signal is supplied from the transceiver, and on the other hand, internal antennas. Using internal antennas, the repeater relays (transmits) signals from cell phones located at a short distance (up to 600 sq.m.). The repeater creates, as it were, one small cell, in the area of which you can move freely. At the same time, up to several dozens of people can use the repeater at the same time.

An example is the standard Remotek RP12 repeater system, which contains an external Yagi antenna that connects to the repeater using a coaxial cable. The repeater amplifies the received signal (gain 60dB). Next, the signal through the power divider is fed to internal antennas that re-emit the signal in the room.

The ship subsystem of cellular mobile communications operates as follows.

A subscriber located in one of the premises of the ship starts a conversation on the cellular radiotelephone 10. A high-frequency signal through the antenna of the radiotelephone 10 located on the back cover of the radiotelephone is emitted in the room and received by one of the repeater antennas 11 of the repeater 13. In a ship’s room loaded with various kinds with equipment, it will be necessary to install several repeater antennas in order to avoid “dead” zones and provide communications for crew members located at different points in the room. Several antenna repeaters 11 are connected to the repeater 13 using a power divider 12. Repeater repeater 13 receives a given frequency band and amplifies it in the channels Uplink and Downlink. Proper selection of the type of antennas and their installation locations allows you to minimize the interference inherent in bandpass repeaters. Variable gain allows you to configure and optimize the best coverage. A sufficiently high output power allows the high-frequency signal to be divided between repeater antennas for various internal configurations of the objects of the proposed location.

The repeater monitors its own operating parameters and provides relevant information to the indicators when faults and emergencies are detected. External overload indicators, channel-by-channel, Uplink and Downlink, significantly simplify the installation of repeater antennas so that interference from several antennas at the input of transceiver 14 is minimal.

The high-frequency signal hits the input of the transceiver 14, amplified in a low-noise amplifier and undergoes a double frequency conversion. From the output of the amplifier of the second intermediate frequency (IF) of the transceiver 14, the signal is fed to the input of the amplifier of the intermediate frequency 15 in order to compensate for losses during further propagation of the intra-ship communication complex via low-frequency cable 9. The cellular signal to the second frequency converter through the interface device 16 enters the fixed cable of the ship’s intra-ship communication, and through it enters the ship’s premises with the equipment of the base station. Through the interface device 20, the signal is input to the conversion and filtering device 21, in which the signal is converted to an intermediate frequency (of the order of 90 MHz). The converted signal from the output of the amplifier 26 is fed to the transmitting input of the transceiver 18, where it is converted to a high-frequency signal, which through the antenna input of the transceiver 18 and the power divider 3 is fed to the input of the multi-channel transceiver of the base station 4 and the antenna of the base station 1. This completes the propagation path of the cellular signal communication from the subscriber to the base station.

It is known that when the cellular network is functioning, the base station 2 is continuously interacting with subscriber 10.

The feedback signal from the base station 2 to the subscriber 10 is distributed along the path: power divider 3, transceiver 18, intermediate frequency amplifier 19, interface device 20, interconnect cable 9 of the VKS complex, interface device 16, conversion and filtering device 17, transmitting channel of the transceiver 14, repeater 13, power divider 12, repeater antenna 11 and the radiotelephone of the subscriber 10.

The direct and reverse cellular signals between the base station and the subscriber's radiotelephone are distributed via the inter-post cable 9 located between the interface devices 16 and 20. However, these signals will not interfere with each other, because the reception and transmission of one subscriber are separated in time, and the signals of different subscribers are also separated in time: the GSM standard uses time division multiple access (TDMA).

Further interaction of the base station and the subscriber is carried out in a standard way. The signal can be emitted by the antenna of the base station into the outer space, as well as transmitted to other spaces of the ship for communication with ship subscribers in the following way: power divider 3, transceiver 18, intermediate frequency amplifier 19, interface device 20, interconnect cable 9 of the VKS complex, interface device 16, a conversion and filtering device 17, a transmitting channel of a transceiver 14, a repeater 13, a power divider 12, a relay antenna 11, and a radiotelephone of a subscriber 10.

Thus, the proposed ship subsystem of cellular mobile communications can provide cellular communication between subscribers located in different spaces of the ship, as well as between subscribers of the ship and external subscribers located in the coverage area of the antennas of base stations.

The technical and economic effect of the introduction and use of the ship subsystem of cellular mobile communication is to expand the scope of cellular mobile communication systems by making it possible to operate on ships and other mobile objects where subscribers are in shielded rooms relative to the antenna of the base station. At the same time, subscribers receive cellular services, and operators receive additional profit by increasing the number of subscribers.

Literature

1. Andrianov V.I., Sokolov A.V. Mobile communications. - SPb .: BHV - St. Petersburg, 1998.

2. Remotek - GSM repeaters. Solve the problem with poor mobile communications! 2008. The company "Alpha Radio". 2008.

3. Wireless dungeon. Source: Mobile News January 15, 2009 (Mikhail Kamishin), www.note.mnovosti.ru.

4. Alekhin Yu.N., Lazareva E.V. Antenna-feeder devices for base stations of cellular and mobile communications. GSPI RTV. 2009 year

5. Automation control and communications in the Navy. / Under the total. ed. Yu.M. Kononova. Ed. 2nd. - St. Petersburg: "Elmore", 2001.

Claims (1)

The ship’s cellular mobile subsystem, consisting of n subscriber (by the number of subscribers) radiotelephones with antennas and m repeater antennas located in each room of the facility and connected through the first power divider with a repeater, and base station equipment located in one of the ship’s rooms and consisting of an antenna and series-connected multichannel transceiver, controller, transcoder and a mobile switching center, characterized in that it also includes fast switching ion centers and inter-post cables connecting them from the intra-ship communication complex, as well as transceiver located in each room of the ship and connected in series, the first intermediate frequency amplifier, the first device for interfacing with the post cable for intra-ship communication, the first signal conversion and filtering device, the output of which is connected to the second input of the transceiver, as well as placed in the room where the equipment of the base station is located, connected in series to the second a power extender connected between the antenna of the base station and the multi-channel transceiver, the second transceiver, the second intermediate frequency amplifier, the second device for interfacing with the post cable of the intra-ship communication, the second signal conversion and filtering device, the output of which is connected to the second input of the second transceiver, while the second inputs of the devices interfaces with the post cable of the intra-ship communication are connected to the corresponding outputs of the post switching centers, and the second outputs are interposed cable from the intrabuilder communications complex, each conversion and filtering device consists of a series-connected first bandpass filter, a mixer, a second bandpass filter and an intermediate frequency amplifier, as well as a local oscillator, the output of which is connected to the second input of the mixer, and each transceiver consists of an analog parts of a standard digital cordless telephone.

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