RU2375819C2 - Method of frequency planning in mobile communication systems - Google Patents

Abstract

FIELD: physics; communications.

SUBSTANCE: method relates to electro- and wireless communication, specifically to a method of frequency planning in ground based mobile communication systems. For this purpose, the network deployment territory is divided into three types of service areas: covered service areas, partially covered service areas and uncovered service areas. Frequency resources are distributed in the said areas and depending on conditions of movement of the mobile base station, frequency domain is created. The standard of operation of the mobile base station is the same as the standard of operation of the ground based mobile communication network to which the mobile base station belongs. When the mobile base station moves through covered service areas, frequency resources are distributed through dynamic frequency planning. When the mobile base station moves through partially covered service areas, frequency resources are distributed for covered sections through dynamic frequency planning, and for uncovered sections, a frequency corridor is created.

EFFECT: larger coverage areas for ground based mobile communication networks, improved quality of servicing subscribers of electro- and wireless communication networks.

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Description

The method relates to the field of electrical and radio communications, and in particular to a frequency planning method in land mobile communication systems.

A known method of frequency planning in land mobile communication systems [see Makoveeva M.M. Shinakov Yu.S. "Communication systems with moving objects": Textbook. manual for universities. - M.: Radio and Communications, 2002. p.13-21.]

The disadvantages of this method are the stationarity of the base stations of the land cellular communication system, which makes it difficult to provide mobile communications to mobile objects that are outside the scope of land cellular communication systems, the rigid distribution of the frequency resource in the served territory, which leads to the recalculation of the frequency-territorial plan when introducing or removing the base station.

A known method of constructing radio communications in a cellular structure network [RF patent No. 2269872, 2006], relating to radio communications and information transfer, which consists in the fact that base stations are located at the vertices of equilateral pentagons with two non-adjacent right angles covering the served territory without gaps, at the same time, stations with a smaller radius are located at the vertices of squares formed by the intersection points of mutually perpendicular straight lines passing through three successive base stations, and provide network connection at an elevated probability of failure nodes and links.

The disadvantages of the method are the rigid distribution of the frequency resource between the cells in order to avoid negative mutual influence between the base stations, which makes it difficult to move the mobile base station through the territory covered by such a network.

A known method of dynamically redistributing the load of base stations of a cellular communication network and a device for its implementation (option) [RF patent No. 2181229, 2002], related to the field of radio communications and applicable mainly in cellular communication systems with multiple access technology with code division multiplexing, which consists in in that they connect one or more active duplex signal repeaters to donor (i.e., temporarily underloaded) base stations. Signal repeaters are installed in the service area of the base station, which for some reason may be unable to service the load that occurs at a certain point in time. For example, at the venue of a one-time mass event - exhibitions, conferences, fairs, etc.

The disadvantages of this method are the limited network coverage range of the antennas of stationary base stations, which does not allow using this method to provide cellular communications to a large mobile group of subscribers traveling long distances to areas not covered by cellular mobile radio communications (cruise ships, ferries, railway trains and other large moving objects).

The closest analogue of the proposed method is a device and method for additionally introducing a base station into a cellular communication system and excluding a base station from this system [RF patent No. 2137306, 1999]. It includes the addition of a base station to a cell in a cellular communication system and excludes the base station from it when the system load increases or decreases accordingly or if the base station needs maintenance.

The main operations of this method

The introduction of a new base station by initially establishing a high level of loss in the receiving path of the new base station, establishing a high level of attenuation in the transmitting path of the new base station, then coordinating the reduction of attenuation in the receiving and transmitting path and increasing the transmit power level of the new base station. The operation of introducing a new base station is completed when its transmitted power reaches a predetermined desired level. When a base station is removed from a network of base stations, its service area is reduced. The removal procedure is continued until the service areas are reduced to zero. After that, the deleted base station ceases to work, and the coverage areas of neighboring base stations expand to fill the area freed by the remote base station. Information is transmitted in this method using code division multiple access (CDMA) methods.

The specified device and method of additionally introducing a base station into a cellular communication system and excluding a base station from this system is the closest to the claimed object and is selected as a prototype.

The disadvantages of this device and method include:

The limited coverage of the system by the coverage of the land-based land mobile communication system, as an introduced or deleted base station is, in fact, a stationary base station capable of increasing the network capacity at a given territorial site in the desired period of time. Limited use of communication standards, as this system is used only in communication systems that support code division multiple access, which complicates the use of the device and method in communication networks of other standards, increases the complexity of manufacturing transceiver equipment, which leads to an increase in the cost of commissioning a communication network.

The technical task is to create a frequency planning method in mobile communication systems consisting of stationary base stations (SBS) and mobile base stations (SBS) operating in various standards.

The technical result is an increase in the coverage area of terrestrial mobile communication networks, improving the quality of service for subscribers of electric and radio communication networks.

It is achieved by the fact that in the proposed method, the network deployment area is divided into three types of service areas: covered service areas (PZO), partially covered service areas (CPZO) and uncovered service areas (NPZO), they distribute the frequency resource and depending on The frequency corridor is being developed for the moving conditions of the mobile base station, the standard of operation of the mobile base station is set to the same as the standard of operation of the land mobile network to which the mobile base Dancing.

When the BSS moves through the covered service areas, the frequency resource is allocated using dynamic frequency planning.

When the BSS moves through partially covered service areas, the frequency resource is allocated for covered areas using dynamic frequency planning, and a frequency corridor is developed for uncovered areas.

PZOs include service areas (ZOs) in which land mobile communication networks already exist, for example, cities, railway junction stations, ports and coastal areas of settlements and places of mass recreation.

ZBZ include ZO in which, depending on the terrain or other conditions of signal propagation, uncovered sections of a relatively small area may appear where subscriber devices can be located, for example, city outskirts, settlements, railway stations and other places where the number of subscribers may vary greatly depending on the season or time of various events.

Refineries include AOs in which there is no coverage by a terrestrial mobile communication network, for example, waters of seas, lakes, rivers, intercity railways and highways, airways, forests, venues for fishing and oil and gas fields, logging operations, as well as other objects and AOs whose location and the number of subscribers on which can vary greatly depending on the season or time of various events.

Frequency planning when passing the BSS through the PZO is carried out using dynamic frequency planning (figure 1 "Scheme of frequency planning using a dynamic frequency plan in the PZO") or use the frequency corridor (figure 2). The essence of dynamic frequency planning (Fig. 1) is to reassign the frequency channels of BSS 6 as it moves along route 7 relative to a fixed cellular communication network depending on the presence of spurious interference. The essence of the use of the frequency corridor (Fig. 2) consists in such frequency planning of a stationary mobile communication network so that its frequency channels do not cause spurious interference along the entire path of 7 BSS 6, that is, the interfering frequencies are assigned with the necessary protective interval from the approved route (frequency corridor) PBS.

Frequency planning during the passage of BSS through the refinery is carried out using the frequency corridor (Fig.3 "Scheme of frequency planning using the frequency corridor in the refinery"), which is an approved route 7 for the movement of BSS 6, in the territory of which it is allowed to use the frequencies assigned to the BSS.

Frequency planning during the passage of the BSS through the LSSP is carried out depending on the propagation conditions and the signal level of the SBS serving the LSS and the situation, using dynamic frequency planning or organizing a frequency corridor (Fig. 4 “Frequency planning scheme using a frequency corridor in a refinery”).

Examples of the practical use of the frequency planning method in mobile communication systems.

Example 1. Carried out frequency planning (frequency resource allocation) when moving the BSS through the territory covered by the cellular network, using dynamic frequency planning.

They moved BSS 6 with a coverage area R1 supporting the entire spectrum of network frequencies from f ₁ to f ₃₈ along route 7 through the coverage areas of stationary base stations 1, 2, 3, 4, 5 inside the same network (Fig. 1). When BSS 6 entered zone 1, BSS 6 cells in this zone were perceived as neighboring, similar to stationary BS, and subscribers located in the coverage area of both stations, as the stationary base station of zone 1 is loaded, automatically, under the control of controller 8, associated with all stationary and mobile base stations with connecting lines 9, switched to the free channels of BSS 6. When the BSS 6 continued to move to zone 2, controller 8 evaluated the signal-to-noise ratio, (in this case, the signal level in the zone is stationary of base station 2 with a signal from BSS 6.) and, if necessary, by selection method changed the number of frequency channel BSS 6 so that the signal-to-noise ratio in the coverage area of base station 2 was within acceptable limits (in figure 1, the number of the frequency channel PBS 6 with 135 was replaced in zone 2 by frequency channel 122).

As BSS 6 moved from zone 1 to zone 2, the radiation power level of BSS 6 for zone 1 subscribers decreased due to its constant removal, and subscribers automatically switched without breaking the cell to the cells with the highest signal level in zone 1. Thus, subscribers did not noticed the removal of PBS 6 from zone 1.

In zone 2, a similar introduction and removal of BSS 6 occurred, since on controller 8 all sectors of BSS 6 with unique numbers were entered in the list of neighboring cells for all sectors of stationary base stations along the route. Due to the fact that the evaluation of the signal-to-noise ratio by the controller of the base stations 8 took place continuously, the change in the frequency channel occurred as necessary if this ratio did not meet the established requirements. And if necessary (Fig. 1), as indicated for zone 3, there was a repeated replacement of the emitted frequency channel from channel f ₂₂ to channel f ₂ .

With further movement of BSS 6 along the established route 7 through cells 3, 4, 5, the above operations occurred until BSS 6 left the area covered by cells similar to cells 1, 2, 3, 4, 5. In view of the fact that the signal-to-noise ratio in zones 3, 4, 5 (Fig. 1) when PBS 6 moved through them was within acceptable limits, there was no need to change the frequency channels on PBS 6.

Example 2. Carried out frequency planning (frequency resource allocation) when moving the BSS through the territory covered by the cellular network using the frequency corridor (figure 2).

They moved BSS 6 with a coverage area R1 supporting the entire spectrum of network frequencies from f ₁ to f ₃₈ along route 7 through the coverage areas of stationary base stations 1, 2, 3, 4, 5 within the same network.

When BSS 6 entered zone 1, BSS 6 cells in this zone were perceived as neighboring, and subscribers located in the coverage area of both stations, as the stationary base station of zone 1 is loaded, automatically, under the control of controller 8, associated with all stationary and mobile base stations connecting lines 9, switched to the free channels of the BSS 6.

As BSS 6 moved from zone 1 to zone 2, the radiation power level of BSS 6 for zone 1 subscribers decreased due to its constant removal, and subscribers automatically switched without breaking the cell to the cells with the highest signal level in zone 1. Thus, subscribers did not noticed the removal of PBS 6 from zone 1.

In zone 2, a similar introduction and removal of BSS 6 took place due to the fact that on controller 8 all sectors of BSS 6 with unique numbers were entered in the list of neighboring cells for all sectors of stationary base stations along the route.

The signal-to-noise ratio is not evaluated by controller 8, since the frequency plan is designed in such a way that frequency channels that can cause spurious interference are not used (or are used with a sufficient protective interval) along the BSS 6 with a radius of action R1 (in FIG. 2, frequency channel No. 2 is assigned for BSS 6, which is not used in the stationary network along the entire path of BSS 6).

Example 3. Carried out frequency planning (frequency resource allocation) when moving the BSS through the territory uncovered by the cellular network, using the creation of a frequency corridor, (figure 3).

They moved BSS 6 with coverage area R1 along an uncovered service area, for example, Sea 11. For this, route 7 for moving BSS 6 with coverage area R1 was approved, on which the frequency situation was evaluated, i.e. the nominal frequencies and power of the signals of other transmitters operating in the routing zone 7. Then, depending on the situation, the radius of the coverage zone R1 of the BSS 6 was changed, thus obtaining a frequency corridor 10 in which the BSS 6 with a variable radius of action R1 worked (that is, with an adjustable radiation power at a constant frequency).

In order to avoid negative influences, PBS 6 was put into operation in the frequency band when it completely left the PZO. When BSS 6 again approached the PZO, it was turned off, or in order to avoid negative effects with stationary BSs, the PZO reduced the power in the stable communication zone of the stationary network 13. In the case of short-term passage along the coverage area of the stationary network 12, dynamic frequency planning was performed.

The communication of BSS 6 with the terrestrial network was carried out using relayings using space channels or using high-altitude atmospheric platforms, or terrestrial radio relay lines.

Example 4. Carried out frequency planning (frequency resource allocation) when moving the BSS through an area partially covered by a cellular network using dynamic frequency planning and (or) creating a frequency corridor.

They moved the BSS 6 with the coverage area R1 through territory 14 (Fig. 3), there were sections 15 on it, which for various reasons were not covered by the cells of the mobile communication system.

PBS 6 was turned on in cell 1, if PBS had 6 frequencies that cause spurious interference to a stationary network, a dynamic selection of frequencies occurred. When BSS 6 entered zone 1, BSS 6 cells in this zone were perceived as adjacent to the stationary network, and if the signal-to-noise ratio between BSS 6 cells and SBS did not satisfy the requirements in this zone, then under the control of controller 8, the frequencies were replaced. Enumeration of the alternating frequencies occurred until the signal-to-noise ratio did not satisfy the required conditions (see Example 1).

In the case when there was no need for additional channels in zone 1, the BSS was not included in it. And included PBS 6 only in section 15.

During the transition of BSS 6 to section 15, which, for various reasons, the cellular communication system did not or did not serve, but with an unacceptable quality, the route 7 for the movement of BSS 6 was approved. Due to the absence of interference frequencies in section 15, it was not necessary to change the frequency channels for BSS 6. PBS 6 with a radius of action of R1 provided mobile territory along route 7.

The communication of BSS 6 with the ground network when moving through section 15 was carried out using retransmissions using either space channels, or using high-altitude atmospheric platforms or terrestrial radio links.

When BSS 6 was approaching a new section 16, in which subscribers were serviced with acceptable quality by a fixed network, BSS 6 was turned off or put into dynamic frequency distribution mode under the control of controller 8.

This method allows you to increase the coverage of terrestrial mobile networks and improve the quality of service for subscribers of electric and radio networks.

Claims (3)

1. The method of frequency resource allocation, which consists in the fact that the network deployment area is divided into three types of service areas: covered service areas, partially covered service areas and not covered service areas, when moving a mobile base station (BSS) from one service area to another with a stationary base station, all cells of the indicated BSS with unique numbers in this area are perceived as neighboring, and subscribers who are in the coverage area of both stations, as the stationary base station is loaded Zone stations automatically switch to free BSS channels, changing the frequency channel number if necessary, while frequency resource distribution is carried out depending on the conditions of movement of the mobile base station in various service areas, the standard of operation of the mobile base station is set to the standard of the land mobile network the communication to which the mobile base station belongs. 2. The method according to claim 1, characterized in that when moving the mobile base station through the covered service areas, the distribution of the frequency resource is carried out using a dynamic frequency distribution of the resource. 3. The method according to claim 1, characterized in that when moving the mobile base station through partially covered service areas, the frequency resource is distributed for covered areas using dynamic frequency planning, and a frequency corridor is developed for uncovered areas.

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