KR20050021975A - A three-dimension coverage cellular network - Google Patents

Abstract

Disclosed are a network, method, base station, and antenna for establishing three-dimensional cellular signal coverage in a cellular communication system, particularly in the upper floors of urban skyscrapers. In order to extend the base station coverage to the space above the ground surface, the uptilt antenna and the downtilt antenna are combined with each other to share the base station transceiver, thus sharing the cellular frequency spectrum, thereby extending coverage and avoiding interference. The downtilt antenna covers the earth's surface, and the uptilt antenna covers the space above the earth's surface, in particular the top floor of a tall building in the cell. The multibeam multitilt base station antenna replaces the downtilt and uptilt antennas to provide three dimensional coverage with one antenna. The multibeam multitilt base station antenna has one beam directed downward to cover the ground surface at the base station and another beam directed upward to cover the space above the ground surface.

Description

3D Service Area Cellular Network {A THREE-DIMENSION COVERAGE CELLULAR NETWORK}

Reciprocal Citation of Related Applications

The present application discloses Canadian Patent Application No. 2,393,552 (filed July 31, 2002, titled "Methods and antennae for High-Rise Coverage of Terrestrial Cellular Wireless Communications". Systems ""), the entire contents of which are incorporated herein by reference.

The present invention relates to ground and ground cellular signal coverage for cellular communication systems. The present invention relates to a network, a method, a base station and an antenna that can eliminate interference in a certain area when constructing three-dimensional cellular signal coverage for a cellular communication system.

A mobile cellular communication system (simply referred to as a "mobile cellular system" or "cellular system") was originally invented by Bell Telephone Laboratories (US Pat. No. 3,663,762) in the 1970s and generally includes at least one MSC. It is known to include a plurality of mobile stations and a plurality of terrestrial subscriber radio stations distributed over a certain area. It includes at least one control channel and a group of traffic channels and provides mobile radio access communications services to terrestrial subscriber radio stations using radio frequencies or frequency spectrums allocated for cellular mobile communications. Each base station includes a base station transceiver system (BTS), at least one base station antenna, and antenna support structures (such as towers, columns, rooftops, etc.) and serves a terrestrial area, i.e., a terrestrial cell, that one or more base station antennas are responsible for. To provide. Each terrestrial cell may be further divided into a plurality of terrestrial sectors, and one or more base station sector antennas are responsible for each sector. Radio frequency or radio frequency spectrum is reused in these terrestrial cells or sectors. The BTS includes a plurality of transmitters and a plurality of receivers, which consist of at least one control channel and a plurality of traffic channels. Dedicated radio frequency bands are assigned to mobile cellular systems in specific regions. In North America, two frequency bands are assigned to mobile cellular systems, one for the 800 MHz band with transmit frequencies from 824 MHz to 849 MHz, and one for frequencies from 869 MHz to 894 MHz, and one for transmit frequencies from 1850 MHz to 1910 MHz. It is a 1900 MHz band with a reception frequency from 1930 MHz to 1990 MHz.

Cellular systems are based on two basic concepts: cell and frequency reuse. Certain areas are generally represented by hexagons that border each other and are divided into smaller service areas that make up the cellular pattern. The base stations are located approximately in the center of each cell, and their antennas are installed in towers (or pillars, rooftops, etc.) to transmit / receive radio signals and communicate with subscriber stations in their cells. The advantage of this method is that the network capacity is greatly increased with a limited frequency spectrum. Today, these cellular methods are such as advanced mobile communication systems (AMPS), time division multiple access (TDMA) systems, world mobile communication systems (GSM), code division multiple access (CDMA) systems, and third generation (3G) cellular systems. It is widely used in various mobile cellular systems. (Cell refers to the area or space that a base station corresponding to a particular logical recognition on a radio path or its base station is responsible for. Mobile stations within a cell can communicate with corresponding base station radio equipment.

Radio frequency reuse of cells can cause interference. In frequency division multiple access (FDMA) cellular systems (such as AMPS) and TDMA cellular systems (such as GSM), radio frequency reuse causes co-channel interference. In order to minimize co-channel interference, the cellular network architecture is designed to increase the distance from the co-channel interferer to the subscriber station. Cells are organized in clusters. One cluster is one cell group. Within a cluster of cells, the entire available frequency spectrum can be used. Some of the total number of frequency channels is allocated to each cell, and neighboring cells in the same cluster are assigned frequency groups of different groups. There is no reuse of radio frequencies within the cluster. The frequency channel configuration in the cluster is then repeated in all clusters of the cellular network. In this structure, the frequency reuse distance is much larger than the cell radius, which helps to reduce the same channel. One cell may in turn be divided into a plurality of sectors with a directional sector antenna. Each sector is responsible for a partial region of that cell. Each sector is assigned a portion of the cell's entire frequency channel. The orientation of the sector antenna further reduces co-channel interference. In CDMA cellular systems, all cells use the same spread spectrum over a wide frequency range. Interference is caused by an increase in communication within the cell, and also from adjacent cells. Interference by adjacent cells causes noise floors for the system. The weaker the signal emitted to adjacent cells, the less interference the system will have. One way to control interference in a cellular system is to include a base station radio signal in its cell.

As shown in Figures 1A and 1B, down-tilt beam base station antennas (hereinafter, simply referred to as "downtilt antennas") are a widely used method in mobile cellular systems (US Pat. No. 4,249,181). The downtilt antenna radiates the signal downwards, and can reduce interference in cellular systems by embedding the signal only within its own cell and preventing it from radiating to adjacent cells. Downtilt antennas help reduce interference, but they are expensive. Since the beam radiated from the downtilt antenna is directed down to the ground, the radio signal is very weak in the space above the downtilt antenna, especially near the cell boundary. When using a downtilt antenna, the spatial coverage pattern of the cell is like a large dome (shown in Figures 1C and 1D), high in the center and low at the border. Radio signals out of cell coverage are not strong enough to allow communication. (Hereinafter, a cell that is in charge of a down tilt antenna or an antenna without a beam tilt will be called a "ground cell", and a cell that is in charge of a down tilt sector antenna or a sector antenna without a beam tilt is called a "ground sector". A cellular network composed of terrestrial cells and terrestrial sectors will be referred to as "ground cellular network." The term "ground" is intended to emphasize its coverage target.)

Mobile cellular systems were developed to provide mobile communication on the ground. Its network configuration and system design are based on mobility and ground coverage. Traditionally, mobile cellular networks treat their coverage areas as ground surfaces and cover only the ground. This is basically a two-dimensional coverage network. The world is three-dimensional. There are many skyscrapers in cities, especially big cities. Because the height and downtilt of the base station antennas are limited, the upper floors of many skyscrapers are out of the service area of a mobile cellular network. Advances in technology have allowed subscriber stations, such as mobile phones and BTSs, to become more sensitive and able to detect even weak signals, but still the cellular signals at the top of many skyscrapers are too weak for good communication. Is proven. In addition to the signal loss caused by free space, there are two major additional signal losses between the base station in the cell and the mobile phone in the upper floors of the skyscraper. One is the penetration loss that occurs when passing through the walls and / or windows of a tall building. This results in an average loss of about 20 dB. The other is due to the down tilt of the base station antenna. The upper floors of many high-rise buildings are not in the main lobe coverage of the downtilt antenna, but in the null zone of the downtilt antenna. In general, the gain of a cellular base station antenna is about 20 dB less in the air than in the mains. This results in an additional loss of 20dB on average. At the top of most skyscrapers, the cellular signal is on average about 40 dB lower than the cellular signal on the ground at the same location. That's why it's hard to talk on a cellular phone at the top of many skyscrapers. On the other hand, in the lower floor or the lower floor of a high-rise building within the main tilt coverage of the downtilt antenna, the cellular signal has a penetration loss of about 20 dB on average except for signal loss caused by free space. The cellular signal here is much stronger than at the top of most skyscrapers in the same area. In most cases, the quality of cellular phone calls is excellent. 20 dB is very important in wireless communications, especially in weak wireless signal environments such as indoors. In order to solve the problem of coverage on the upper floors of high-rise buildings, existing mobile cellular networks need to be changed. (The antenna main lobe is the lobe of the antenna radiation pattern that contains the maximum radiant energy, sometimes referred to as the "main lobe" or "beam.")

In rural areas where communication traffic is low, cells are designed to be as large as possible to cover larger areas. In these areas, base station antennas typically have a small down tilt angle or no tilt angle at all. In areas such as cities with high communication traffic, cells are designed to be much smaller than in rural areas. In these areas, most base station antennas have a larger down tilt angle than rural areas to avoid interference because the radiation from the antenna is contained within a small cell. Base station antennas are typically installed on rooftops 20 to 40 meters above the ground, taking into account interference, cell size, aesthetics, cost, and site availability. Thus, the upper floors of many high-rise buildings in urban areas, especially large cities, are spatially outside of mobile cellular network coverage. In practice, however, the upper floors of many skyscrapers have little or no signal coverage. People work and live there. As mobile phones become widespread worldwide, mobile cellular signal coverage in skyscrapers is now a major concern for both service providers and consumers.

Systems and methods called "distributed antenna systems" (DAS) have been used to provide mobile cellular signal indoor coverage in high rise buildings. This is the introduction of cellular radio signals from a microcell base station or repeater into a building via radio frequency (RF) cables and / or fiber optics. In general, this requires a microcell base station or repeater, a long and complex wireless signal distribution network, and many indoor antennas. Wireless signal strength is limited to cover a small area around the indoor antenna. Unfortunately, DAS systems are not a cost-effective solution for high-rise building coverage. Microcell base stations or repeaters and distribution networks are very expensive. It is equally expensive to rent a room for a microcell base station or a repeater and distribution network in a tall building. In addition, in order to operate the distribution network, the building owner's permission is required and the installation cost is very expensive. To build full coverage in every building, the system must be run from floor to floor at a high cost. Paid traffic in the coverage of the DAS system is limited. In general, the benefits of simply operating a DAS system will be less than the investment cost of building it. This is why DAS systems are not widely available.

Thus, there is a need for a more practical and cost effective solution for deploying cellular signal coverage on top of skyscrapers in cellular systems.

1A (Prior Art) illustrates a typical base station and its coverage of a mobile cellular system.

1B (Prior Art) shows a lobe pattern at the height of the downtilt sector antenna in FIG. 1A.

1C (Prior Art) shows a schematic 3D coverage shape of a typical terrestrial cell of a mobile cellular system.

1D (Prior Art) shows a schematic 3D coverage shape of a terrestrial mobile cellular network.

2A shows an uptilt sector antenna covering the upper floors of a tall building.

FIG. 2B shows an uptilt omnidirectional antenna covering the upper floors of a tall building. FIG.

FIG. 2C shows an uptilt transmit / receive sector antenna covering an upper floor of a tall building. FIG.

2D shows a lobe pattern at the height of the uptilt sector antenna in FIG. 2A.

2E shows a schematic 3D coverage shape of the top cell of the present invention.

2F shows a schematic 3D coverage shape of the top cell and sector of the present invention.

2G is a schematic 3D coverage shape of the upper cellular network of the present invention.

3A shows a spatial coverage profile at the height of an upper cellular network superimposed on a terrestrial cellular network in a first scheme.

3B shows a spatial coverage profile at the height of the upper cellular network superimposed on the terrestrial cellular network in a second manner.

3C shows a spatial coverage profile at the height of the upper cellular network superimposed on the terrestrial cellular network in a third scheme.

FIG. 3D shows a spatial coverage profile at the height of the upper cellular network superimposed on the terrestrial cellular network in a fourth scheme.

4A illustrates an embodiment of a method of the present invention and a shared base station for canceling interference between an upper cell and a terrestrial cell.

4B illustrates an embodiment of a method and a transmitter and receiver of a shared base station of the present invention for canceling interference between an upper cell and a terrestrial cell.

4C illustrates an embodiment of a method for canceling interference between an upper cell and a terrestrial cell using a dedicated frequency or frequency spectrum in the upper cellular network.

5A illustrates an embodiment of a system architecture of the upper cellular network of the present invention.

5B illustrates an embodiment of system integration of an upper cellular network and a terrestrial cellular network.

5C illustrates an embodiment of system integration of an upper cellular network and a terrestrial cellular network.

5D illustrates an embodiment of system integration of an upper cellular network and a terrestrial cellular network.

6A (Prior Art) shows a typical base station sector antenna and its beam pattern and coverage.

6B illustrates an embodiment of a method for providing tall building coverage with a narrow beam antenna.

7A illustrates an embodiment of the multibeam multitilt antenna of the present invention in a single band.

7B shows a lobe pattern at the height of the antenna of FIG. 7A.

7C shows an embodiment of the multibeam multitilt antenna of the present invention in dual band.

7D shows a lobe pattern at the height of the antenna of FIG. 7C.

7E shows an embodiment of a mechanical beam tilting means of a multibeam multitilt antenna.

7F shows an embodiment of an electrical beam tilting means of a multibeam multitilt antenna.

One feature of the cellular communication network of the present invention (also referred to simply as " cellular network ") is that the at least one base station has three-dimensional (3D) spatial coverage over the surface and above the surface, downlinking the transmitter and receiver of the base station (up-tilt) Share between antennas and remove interference by beam downtilting and uptilting of the base station antennas. Another feature of the cellular network of the present invention is that at least one other base station has coverage in a particular space above the ground surface and eliminates interference by beam uptilting of the base station antenna. According to this configuration, the cellular network of the present invention provides a cost-effective solution for establishing 3D spatial coverage in a particular area, in particular for the upper floors of urban skyscrapers.

The present invention also provides a method and base station for establishing a cellular communication network having the above characteristics.

The cellular communication network of the present invention includes a plurality of base stations within a specific area. The cellular communication network of the present invention provides a cellular communication service in a specific area. The specific area is divided into a plurality of cells. Each base station provides a radio signal to a subscriber mobile station in a cell. At least one base station of the cellular network has a ground surface and 3D spatial coverage over the ground surface in the cell. The base station includes a transmitter, a down tilt antenna, and an up tilt antenna. The transmitter generates a radio signal to be supplied into a cell of that base station within a frequency range reusable in one or more cells of the cellular network. The downtilt antenna is coupled to the transmitter to emit radio signals in a radiation pattern whose mains are directed downward. The uptilt antenna is coupled to the transmitter to emit a radio signal in a radiation characteristic pattern whose mains are directed upwards. Thus, radiating a radio signal in a cell of a base station under a downtilt antenna and above an uptilt antenna while preventing the radio signal from radiating into other cells of the cellular network that may interfere with radio signals from other base stations in the cellular network. . The base station further includes a receiver for receiving radio signals generated by subscriber stations in the cell. The receiver is coupled to both the uptilt antenna and the downtilt antenna to receive a radio signal generated by a subscriber station in a cell of the base station through at least one of the two antennas. The two antennas are arranged substantially side by side. The downtilt antenna can be placed in an uptilt antenna position in height. The two antennas may be integrally formed with one antenna. (A radio signal is sometimes simply referred to as a "signal" and is detectable radio energy with information generated by a transmitter or subscriber station.) The antenna radiation pattern is a change in the electromagnetic field strength of the antenna as a function of angle to the axis. appear.

The cellular network of the present invention includes at least one of the base stations having coverage in the space above the ground surface. The base station includes a transmitter and an uptilt antenna. The transmitter generates a radio signal to be provided within a cell of that base station within a frequency range reusable in one or more cells of the cellular network. The uptilt antenna is coupled to the transmitter to emit a radio signal in a radiation characteristic pattern whose mains are directed upwards. Thus, it radiates a radio signal in a cell of a base station above the uptilt antenna, but prevents the radio signal from being radiated into other cells of the cellular network that may interfere with radio signals from other base stations in the cellular network. The base station further includes a receiver for receiving radio signals generated by subscriber stations in the cell.

According to the present invention, a method for providing a cellular communication service in a specific area divided into a plurality of cells includes generating a plurality of radio signals in a frequency range that can be reused in one or more of the cells, wherein each radio signal Is provided to a subscriber station in the cell. One of the radio signals is provided to the cell by radiating from the downtilt antenna in a radiation characteristic pattern with the jurass pointing downward and radiating from the uptilt antenna in a radiation characteristic pattern with the jurass facing upward. According to the above configuration, in the cell, a radio signal is emitted below the downtilt antenna and above the uptilt antenna, and the radio signal is prevented from being radiated into another cell which may interfere with other radio signals. The method further comprises receiving at least one radio signal from a subscriber station in the cell. The wireless signal from the subscriber station may be received via at least one of the downtilt antenna and the uptilt antenna. All of these antennas can be arranged substantially side by side. The downtilt antenna may be positioned above the uptilt antenna in height. The down tilt antenna and the up tilt antenna may be integrally formed of one antenna.

The method further includes the step of providing the other radio signal to the cell by radiating another radio signal from the uptilt antenna of the cell in a radiation characteristic pattern whose direction is upward. According to the above configuration, the other radio signal is radiated over the uptilt antenna in the cell, and the other radio signal is prevented from being radiated into another cell which may interfere with another radio signal.

The base station of the cellular communication network of the present invention further includes a transmitter, a down tilt antenna, and an up tilt antenna. This cellular network provides a plurality of cellular radio signals to a particular area divided into a plurality of cells. The transmitter generates a radio signal to be provided in a cell of the base station. The transmitter operates within a frequency range that can be reused in one or more cells. A downtilt antenna is coupled to the transmitter to emit a radio signal in a radiation characteristic pattern whose mains are directed downward. An uptilt antenna is coupled to the transmitter to emit a radio signal in a radiation characteristic pattern whose mains are directed upwards. Thus, while radiating a radio signal in a cell of the base station below the downtilt antenna and above the uptilt antenna, the radio signal is prevented from being radiated into other cells that may interfere with other radio signals in the cellular network. The base station further includes a receiver for receiving radio signals generated by subscriber stations in the cell. The receiver is coupled to the downtilt antenna and the uptilt antenna to receive a radio signal generated by the subscriber station in the cell of the base station through at least one of the downtilt antenna and the uptilt antenna. The down tilt antenna and the up tilt antenna may be integrally formed of one antenna.

The present invention further provides a multibeam multitilt base station antenna having at least two beams in two different directions. This can be used to replace the downtilt and uptilt antennas that provide 3D spatial coverage at the cellular base station with one single antenna. When used in a cellular base station, one of the two beams faces downward to cover the ground surface and the other one is directed upward to cover the space above the ground surface. (An antenna beam, also called an antenna main lobe, is a radiation lobe that contains most of the radiant energy within a limited small angle in at least one dimension.)

1A to 1D are views showing the prior art and its problems.

1A illustrates a typical base station and its coverage of a mobile cellular system. The down tilt sector antenna 1 is connected to the BTS 5 via an RF cable 4. It is installed in the pillar 3. The beam is tilted down at a β angle below the horizontal plane from its installation position. The beam covers the ground surface, the low-rise building 20a, and the lower floor of the high-rise building 20 in its ground sector. The beam does not cover the upper floors of skyscrapers 20. The antenna 1 functions as a transmit and receive antenna. Arrow 51 is the beam (or main lobe) axis. (Sector antennas have a radiation pattern that is oriented in both azimuth and elevation. The beam or jube axis is the maximum power radiation direction of the beam or jube.)

FIG. 1B shows a lobe pattern at the height of the downtilt sector antenna in FIG. 1A in the transmit and receive directions. The antenna has the same lobe pattern in the transmission direction and the reception direction because there is an interdependence relationship between the transmission characteristics and the reception characteristics in the antenna. The main groove 6 of the sector antenna 1 is down tilted at an angle of β below the horizontal plane. (The main lobe direction is the maximum power radiation direction.) 7 denotes a first upper lobe, 8 denotes a first lower lobe, and 9 denotes a rear lobe. Arrow 51 represents the main axis. The blank area between the main lobe 6 and the first upper lobe 7 is around the horizontal plane. This blank area is a space area with the upper floors of many skyscrapers. In general, the cellular signal strength in this blank region is 20 dB below the maximum signal strength of the mains. Hence, due to downtilting of the base station antenna in the cellular system, the cellular signal at the upper floors of most skyscrapers has an average signal strength of 20 dB lower than the cellular signal at the lower or lower floors of the skyscrapers in the same area. The coordinate XY is shown as a reference (the X axis represents the horizontal direction and the Y axis represents the height direction).

1C shows a schematic 3D coverage shape of a typical terrestrial cell of a mobile cellular system. The area and space covered by the downtilt omnidirectional antenna 2 constitute the ground cell 11. It can have a large dome shape that is high at the center and low at the boundary. Reference numeral 13 denotes a boundary of the ground cell 1. The antenna 2 is connected to the BTS 5 and is installed at a height h1 above the ground surface. The ground cell 11 does not cover a space higher than the height h1. This coverage height decreases as the distance from the cell center increases. Because of the interdependence relationship between the transmit and receive characteristics of the antenna, the terrestrial cell 11 has approximately the same coverage shape and range in the transmit direction and the receive direction. (The omnidirectional antenna has a radiation pattern that is omnidirectional in orientation. The vertical radiation pattern can be any shape.)

FIG. 1D shows a schematic 3D coverage shape of a terrestrial mobile cellular network in a transmission direction and a reception direction. The plurality of terrestrial cells are arranged side by side on the surface of the land mobile cellular network. These terrestrial cells only cover the space under their downtil base station antenna. Coverage near these cell boundaries results in worse signal strength and coverage. As mentioned above, land mobile cellular networks do not cover the top floors of many skyscrapers. This is the challenge to be solved. It is an object of the present invention to achieve this problem at low cost. Terrestrial mobile cellular networks have approximately the same coverage shape and range in both the transmit and receive directions.

2A to 2G illustrate the first basic concept of the present invention, where the base station antenna is directed upward to cover the upper floors of a high-rise building, increasing cellular signal strength at the upper floors, and above the ground surface within a particular area. The space of is divided into a plurality of small service spaces, i.e., upper cells, each of the upper cells is covered by one or a plurality of upper mains of the base station antennas in the transmitting and receiving directions, and the plurality of upper cells constitutes the upper cellular network. And cover the space above the earth's surface within that particular area. This configuration allows the upper cellular network to provide cellular signal coverage in the space above the surface of a particular area in mobile cellular systems, particularly in the upper floors of most skyscrapers.

4A to 4C illustrate a second basic concept of the present invention, in which an uptilt antenna and a downtilt antenna are coupled to each other and connected to a base station transceiver. That is, these antennas share a cellular frequency or frequency spectrum by sharing base station transceivers to avoid interference. These antennas may share all or part of the BTS of the base station. The uptilt antenna covers the space above the ground surface, ie the upper cell, and the downtilt antenna covers the ground, ie the ground cell. Since these antennas share the same radio signal source, there will be no interference between the top cell and the ground cell. This interference cancellation technique and the interference cancellation techniques of beam downtilting and beam uptilting can be used in combination to eliminate interference in the entire cellular network.

A base station of a mobile cellular system includes at least one BTS, at least one transmit antenna, and at least one receive antenna. Each BTS includes at least one transmitter and at least one receiver. The transmit antenna is coupled to the transmitter to transmit the radio signal generated by the transmitter to the cell, and the receive antenna is coupled to the receiver to receive the radio signal generated by the subscriber station within that cell. These antennas have approximately the same radiation characteristic pattern. These antennas are installed in the antenna support structure. The transmitter generates a cellular radio signal to be provided to the cell within a frequency range that can be reused in one or more cells of the mobile cellular network. The radio signal generated by the transmitter is radiated from the transmit antenna in a radiation characteristic pattern with its main direction pointing upward above the transmit antenna in the cell. The receiver receives via a receive antenna a radio signal generated by a subscriber station in that cell. Base stations are often used as transmit and receive antennas.

As mentioned above, cellular signal strength will increase on average 20 dB at the top of the skyscraper if the base station antenna is up tilted to cover the top of the skyscraper. Due to the interdependence relationship between the transmit and receive characteristics of the antenna, when the base station antenna is used as the transmit and receive antenna, a radio signal generated by a subscriber station (e.g., a mobile phone) on the upper floor of a skyscraper and received by the base station antenna The intensity of will increase to 20dB on average as in base station receivers. This will greatly change the cellular communication situation on the upper floors of skyscrapers. One uptilt base station antenna may cover the top floors of many tall buildings in that cell. This is a cost-effective coverage problem solution and is easy to implement. (Hereinafter, the beam uptilt base station antenna will be referred to simply as "uptilt antenna", and the beam uptilt base station sector antenna will be referred to simply as "uptilt sector antenna".)

The process of wireless communication between a base station and a subscriber station in a mobile cellular system is a well known technique and is not within the scope of the present invention. Antennas are commonly used as transmit and receive antennas at cellular base stations. This antenna has the same direction selection as those in transmission and reception. This antenna will not receive radio signals from subscriber stations that are out of coverage. For example, the uptilt antenna will not receive radio signals from subscriber stations on the earth's surface in that cell. The uptilt antenna can be used in one way to eliminate interference between cells in the mobile cellular network in the same way as the downtilt antenna. At the base station, separate transmit and receive antennas may be used for certain reasons. These separate antennas have different characteristics to balance the difference between the downlink (from base station to subscriber station) and the uplink (from subscriber station to base station). In any situation, it is desirable for a base station in a mobile cellular network to have the same coverage shape and range in both the transmit and receive directions.

The space above the ground surface is treated as three-dimensional in coverage in the present invention. In the present invention, the concept of the upper cell and the upper sector is introduced in addition to the ground cell and the ground sector. The upper cell is a predetermined space on the ground surface and is a space covered by one or a plurality of mains facing upward from one or more base station antennas. The upper cell may be divided into a plurality of upper sectors (eg, three upper sectors). The upper sector is a predetermined space on the ground surface in the upper cell, and is a space covered by one or a plurality of mains facing upward from one or more base station sector antennas. Each of the upper cells includes at least one BTS and at least one transmit and receive antenna. The antenna is coupled to the BTS and installed in the antenna support structure. Each of the upper sectors includes a BTS and at least one (sending and receiving) sector antenna. The sector antenna is coupled to the BTS and installed in the antenna support structure. Except for the difference in coverage, the upper cells and sectors are not significantly different from the ground cells and sectors. At the network level, like the ground area divided into terrestrial cells, the space on the ground surface within a particular area is divided into a plurality of small service spaces, i.e., upper cells in a mobile cellular system in the present invention. The plurality of upper cells make up the upper cellular network. This covers the space above the earth's surface within a particular area in a mobile cellular system. If necessary, the cellular frequency or frequency spectrum is reused in the upper cells (depending on the type of cellular system and the size of the upper cellular network). The upper cellular network may adopt a frequency reuse scheme similar to that of existing terrestrial cellular networks to eliminate interference between upper cells, such as the 7/21 or 4/12 frequency reuse scheme used in GSM cellular systems. In the present invention, it is preferable to adjust the base station antenna height and its main uptilt angle to remove interference between upper cells within a specific height (depending on the application situation). The upper cellular network further includes at least one control center. The control center is connected to each base station of the upper cellular network. It can likewise be connected with other communication systems. The control center controls the communication between the base station of the upper cellular network and the subscriber station. It also controls communication between the mobile cellular system and other systems. The communication control method of the control center in the upper cellular network is a known technique and does not belong to the scope of the present invention. Conventional terrestrial cellular networks cover the earth's surface. The upper cellular network can be integrated with this existing terrestrial cellular network to extend its coverage into space above the surface of the earth within a particular area. These cellular networks can share a common system control center.

In an application for tall building coverage in a mobile cellular system, the upper main lobe from the base station antenna is directed to the upper floor of the tall building in the upper cell. Each upper cell serves a subscriber station of a mobile cellular system on top of a skyscraper in that upper cell, and each upper sector services a subscriber station of a mobile cellular system on a top floor of a tall building within its upper sector. do. In the present invention, it is desirable to adjust the uptilt antenna height and its main uptilt angle to maximize coverage at the top of the tall building in the upper cell and minimize coverage at the tall building outside the top cell. Existing terrestrial cellular networks cover the lower floors of the earth's surface, low rise buildings, and high rise buildings. The upper cellular network can integrate with this existing terrestrial cellular network to extend its coverage to the top floors of most skyscrapers within a given area. These cellular networks can share a common system control center. The top cellular network can be used in other applications. For example, the upper cellular network can be implemented in a landless mobile cellular system for spatial coverage.

2A illustrates the basic concept of the present invention, where the uptilt antenna covers the upper floors of a high-rise building. The sector antenna 10 is connected to the BTS 15 via an RF cable 4. This antenna is installed in the pillar 3. This antenna has its beam uptilt angle α (eg 10 °) above the horizontal plane from its installation position and points towards the upper floor of the tall building 20 in its upper sector (or upper cell). Arrow 51 represents the beam (or main) axis. The cellular signal generated by the transmitter of the BTS 15 is radiated upward through the antenna 10 and provided to the subscriber station in the upper floor of the skyscraper 20 in its upper sector (or upper cell). The receiver of the BTS 15 receives, via the antenna 10, cellular radio signals generated by subscriber stations within the upper floors of the skyscraper 20 in the upper sector (or upper cell). While FIG. 2A shows a mechanical uptilt, the antenna beam can be electrically uptilted or uptilted in both ways. The antenna 10 may be installed in any antenna support structure such as a tower or rooftop instead of the pillar 3. The coverage goal of the antenna 10 is a high rise building in FIG. 2A, but may be a tower on the ground or other high rise building. In FIG. 2A, the antenna 10 functions as a transmit and receive antenna. It has approximately the same direction selection when transmitting and receiving wireless signals. The BTS 15 has approximately the same coverage in the transmit and receive directions. This means that the upper sector (or upper cell) has approximately the same coverage shape and range in the transmit and receive directions.

2B shows the same concept as FIG. 2A, except that the uptilt antenna 10 is replaced with an uptilt omnidirectional antenna 14. This antenna 14 provides cellular signal coverage in the upper cell.

2C shows the same concept as FIG. 2A, except that the base station 15 uses separate transmit sector antenna 10t and receive sector antenna 10r. The antenna 10t has its beam uptilt angle α (eg 10 °) above the horizontal plane from its installation position and covers its upper sector (or upper cell). It is connected to the transmitters TXs of the BTS 15 via an RF cable 4. The antenna 10r has its beam directed upwards at the same angle α above the horizontal plane from its installation position and covers its upper sector (or upper cell). It is connected to the receiver RXs of the BTS 15 via an RF cable 4. These antennas are installed in the pillar 3. These antennas have approximately the same direction selection. Arrow 51 represents the beam (or main) axis. The cellular signal generated by the transmitter of the BTS 15 is radiated upward through the antenna 10t and provided to a subscriber station in its upper sector (or upper cell). The receiver of the BTS 15 receives, via the antenna 10r, cellular radio signals generated by subscriber stations in the upper sector (or upper cell). The antennas 10t and 10r may have different gains, but preferably have approximately the same coverage range to balance the uplink and downlink.

2D shows a lobe pattern at the height of the uptilt sector antenna in FIG. 2A in the transmit and receive directions. The main groove 16 is tilted up at an angle over the horizontal plane. Reference numeral 17 denotes a first upper lobe, reference numeral 18 denotes a first lower lobe, and reference numeral 19 denotes a rear lobe. Arrow 51 represents the main axis. The blank area between the main lobe 6 and the first upper lobe 7 is around the horizontal plane. In the present invention, it is preferable to generate an empty area between the main lobe 16 and the first lower lobe 18 around the horizontal plane from the antenna installation position by adjusting the antenna uptilt angle. This minimizes cellular signal strength around the horizontal plane at the antenna mounting height, minimizing interference by preventing cellular signals from radiating into other top cells. The coordinate XY is shown as a reference (the X axis represents the horizontal direction and the Y axis represents the height direction).

2E illustrates a schematic 3D coverage embodiment of the upper cell of the present invention in a transmit and receive direction. The space covered by the uptilt omnidirectional antenna 14 constitutes the upper cell 21. It may have a large dome shape that is upside down. Reference numeral 23 denotes the boundary. The antenna 14 is connected to the BTS 15 and is installed at a height h2 above the ground surface. The upper cell 21 does not cover a space higher than the height h2. This non-coverage height increases with increasing distance from the cell center. In the present invention, the upper cell preferably has approximately the same coverage shape and range in the transmission direction and the reception direction.

FIG. 2F shows a schematic 3D coverage embodiment of the top cell and top sector. FIG. The upper cell 21 is divided into three upper sectors 22a, 22b, and 22c. Up tilt sector antenna 10a is connected to BTS 15a to cover upper sector 22a, and up tilt sector antenna 10b is connected to BTS 15b to cover upper sector 22b, and up tilt Sector antenna 10c is connected to BTS 15c to cover upper sector 22c. Reference numeral 23 denotes a boundary of the upper cell 21. Three up-tilt sector antennas are mounted at a height h3 above the ground surface. In the present invention, the upper cell preferably has approximately the same coverage shape and range in the transmission direction and the reception direction.

FIG. 2G illustrates a schematic 3D coverage shape embodiment of an upper cellular network. FIG. The plurality of upper cells 21 are placed side by side on the ground surface to form an upper cellular network. In the present invention, it is desirable to adjust the antenna height and its beam uptilt angle appropriately to maximize signal emission in the upper cell and limit signal emission outside the upper cell. Like the downtilt and downtilt sector antennas, which eliminate interference between terrestrial cells, the uptilt and uptilt sector antennas can also eliminate interference between upper cells within a certain height (eg, maximum skyscraper height) within a specific area. have. The upper cellular network will cover the top floors of most skyscrapers within a particular area. This solves the high-rise building coverage problem that has long existed in mobile cellular systems at low cost. The upper cellular network preferably has approximately the same coverage shape and range in both the transmit and receive directions.

The upper cellular network may only be needed in urban areas in mobile cellular systems. If the coverage target (high-rise building) is limited, the size of the upper cellular network will also be smaller compared to the terrestrial cellular network within the same area. This helps to reduce the interference between the upper cells and the interference between the upper cell and the ground cells. In medium or small cities, the upper cells needed may be in all one cluster. (One cluster has 7 cells in the 7/21 frequency reuse scheme.) In this case, the cellular frequency does not need to be reused in the upper cellular network in an FDMA or TDMA mobile cellular system. A single top cell or top sector will suffice to cover several skyscrapers in isolated rural areas. The upper cell, upper sector, and upper cellular network of the present invention may be implemented with various types of mobile cellular systems to provide cellular signal coverage on top of skyscrapers.

In theory, the cellular frequency or frequency spectrum should be reused in the upper cell in the upper cellular network. In a real upper cellular network, whether the cellular frequency or frequency spectrum is reused does not depend on the type, structure and scale of the upper cellular network. For example, if the mobile cellular system is a CDMA system, all upper cells in a particular area reuse the same spread spectrum. In the case of a TDMA or FDMA mobile cellular system, if the upper cellular network is larger than the cluster, the upper cells may be reused for cellular frequency. In large cities with many skyscrapers in wider urban areas, a large upper cellular network is needed.

3A-3D illustrate embodiments of spatial coverage profiles according to height when the upper cellular network overlaps in various ways on the terrestrial cellular network. The upper cellular network can be superimposed on the existing terrestrial cellular network to extend the coverage of the ground mobile cellular system to space above the ground surface, in particular to the upper floors of skyscrapers. There are several ways to superimpose the upper cellular network on the terrestrial cellular network. 3A to 3D show four examples.

In FIG. 3A, the upper cell overlaps with the ground cells, where the base station antennas of these cells are at approximately the same height at approximately the same trajectory. The upper cells 21b, 21a, 21e (solid line region) overlap the ground cells 11b, 11a, 11e (dashed line region), respectively. The empty spaces 29 between are spaces that the upper cell and the ground cell do not cover. In FIG. 3A, the base station of the upper cell is arranged side by side with the base station of the ground cell.

FIG. 3B shows the same scenario as FIG. 3A, except that the base station antenna of the upper cell is below the base station antenna of the terrestrial cell at approximately the same trajectory. The overlapped space 28 (hatched area) is the area covered by both the top cell and the ground cell. The advantage of overlap in FIGS. 3A and 3B is that the upper cell may share all or part of the existing base station equipment of the terrestrial cell, such as the equipment room, power supply, tower, medium, and the like. As shown in FIG. 4A, even existing BTSs of the terrestrial cell may be shared. The overlapping scheme in FIG. 3B provides better spatial coverage compared to the overlapping scheme in FIG. 3A because there is less uncovered space in FIG. 3B.

In FIG. 3C, the upper cell center is located near the boundary between two ground cells, where the base station antennas of the upper cell and the ground cell are at approximately the same height. The center of the upper cell 21b is near the boundary between the ground cells 11b and 11a, the center of the upper cell 21a is near the boundary between the ground cells 11a and 11e, and the center of the upper cell 21e is It is near the boundary between the ground cells 11e and 11g. The empty spaces 29 therebetween are spaces that the upper cell and the ground cell do not cover.

FIG. 3D shows the same scenario as FIG. 3C, except that the base station antenna of the upper cell is at a height below the base station antenna of the ground cell. The overlapped space 28 (hatched area) is the area covered by both the top cell and the ground cell. The advantage of overlap in FIGS. 3C and 3D is that the position of the upper cell base station can be freely selected. The overlapping scheme in FIG. 3D provides better spatial coverage compared to the overlapping scheme in FIG. 3C because there is more space covered in FIG. 3D.

Practical upper cellular networks can be improved in terms of cost-effectiveness or high-rise building flexibility by combining various overlapping approaches.

4A illustrates a shared base station between an upper cell (or upper sector) and a terrestrial cell (or terrestrial sector), and an important method of the present invention, and a method of avoiding frequency interference between the upper cell and the ground cell. This method is also a method of sharing the cellular frequency or frequency spectrum and base station devices between an upper cell and a terrestrial cell to eliminate frequency interference between those cells.

Because each mobile cellular system has a limited frequency spectrum available, and because almost all of the frequency spectrum has been used in conventional terrestrial mobile cellular systems, especially in urban areas, the upper cellular network must share the cellular frequency or frequency spectrum with the terrestrial cellular network. do. This can cause a new problem called frequency interference between these cellular networks. This problem is easily solved by the present invention. The solution is that the upper cell and the terrestrial cell disposed almost parallel to this cell share all or part of the base station transmitter and receiver. That is, these cells share all or part of the BTS. The shared transmitter and receiver comprise at least one control channel and at least one traffic channel of a mobile cellular system. The transmit antenna of the upper cell and the transmit antenna of the terrestrial cell are coupled to a shared transmitter (TXs) by being coupled to each other through a divider / combiner or coupler (which divides / combines RF signals evenly or unevenly), and the receive antenna of the upper cell The receiving antennas of the and terrestrial cells are coupled to each other through a divider / combiner or coupler and connected to the shared receivers (TXs). In this solution, the upper cell is an extension of the ground cell in the space above the ground surface. There is no interference between these cells. The cellular signal generated by the shared transmitter is radiated over the transmit antenna of the upper cell and provided to a subscriber station in the upper cell. In addition, the cellular signal is radiated below the transmit antenna of the ground cell and provided to a subscriber station in the ground cell. The shared receiver receives the cellular radio signal generated by the subscriber station in the upper cell via the receive antenna of the upper cell and receives the cellular radio signal generated by the subscriber station in the terrestrial cell via the receive antenna of the terrestrial cell. In this situation, the upper cell and the terrestrial cell also share the cellular frequency or frequency spectrum and many mobile cellular system devices such as media or control centers. This solution is very cost effective and easy to implement. Existing mobile cellular systems add up-tilt antennas to their base station antenna systems to extend their coverage to space above ground, especially high-rise buildings, at minimal cost.

4A shows an embodiment of this solution. The uptilt sector antenna 10 of the upper sector and the downtilt sector antenna 1 of the ground sector are coupled to each other via the splitter / combiner 30 (or coupler) to share the BTS 5 via the RF cable 4. It is connected to the transmitter and the receiver. The beam of the antenna 10 is tilted up at an angle α (eg 10 °) above the horizontal plane from its installation position and directed towards the upper floors of the skyscraper 20 in its upper sector. The beam of antenna 1 is tilted down at an angle β (e.g. 8 °) below the horizontal plane from its installation position and directed towards the ground surface and the low rise building 20a in its ground sector. These antennas are provided in the pillar 3. Arrow 51 represents the beam (or main) axis. In FIG. 4A, the upper sector is an extension of the ground sector in space above the ground surface. The cellular signal generated by the transmitter of the BTS 5 is radiated above the antenna 10 to a subscriber station in the upper sector and also to a subscriber station radiated below the antenna 1 in the ground sector. The receiver of the BTS 5 receives the cellular radio signal generated by the subscriber station in the upper sector via the antenna 10 and the cellular radio signal generated by the subscriber station in the ground sector via the antenna 1. do. In FIG. 4A, the uptilt antenna 10 is provided below the downtilt antenna 1, but is provided above or at the same height. In addition, although the antenna 1 is shown by the down tilt sector antenna in FIG. 4A, it may be a down tilt omnidirectional antenna. In addition, although the antenna 10 is shown by the up tilt sector antenna in FIG. 4A, it may be an up tilt omnidirectional antenna. In addition, although the pillar 3 is shown by FIG. 4A, an antenna support structure may be sufficient, such as a tower and a rooftop. Although FIG. 4A shows that the antenna 1 and the antenna 10 share both the transmitter and the receiver of the BTS 5, only some of them may be shared. Inserting a divider / combiner (or coupler) into the antenna in FIG. 4A will result in a loss of about 3 dB to the antenna system in the ground sector (if the RF signal is split evenly). Since most terrestrial cells and sectors in urban areas are small and their base stations use low gain antennas, simply replacing this low gain antenna with a high gain antenna can easily compensate for this loss. In Fig. 4A, the antenna 1 and the antenna 10 function as a transmitting antenna and a receiving antenna, respectively. In this solution, the upper cell (or sector) also shares the control center with the network medium of the terrestrial cellular network. (Here, the divider / combiner divides the radio signal power from one direction in two or more directions in the transmission direction, and combines the radio signals from two or more directions in the reception direction in one direction. When the radio signal power is divided evenly from one direction to two, it is called a power divider, which is a passive element, where the signal information is not processed, the input radio signal and the output radio signal in the transmission direction and the reception direction are exactly the same. Contains information, but differs in signal strength due to the radio path in the divider / combiner or coupler, and there is only a slight time variation between the signals in the transmission direction, output in two or more directions divided from the same input signal The signal contains exactly the same information, but , The signal strength in each direction because the divider / combiner or the radio path in the coupler in each direction may differ slightly from one another may be different from each other and only have a second bit of the time variations between the signals.)

4A also illustrates an embodiment of a shared base station between an upper cell (or upper sector) and a ground cell (or ground sector). The upper cell (or upper sector) and the ground cell (or ground sector) share a common BTS of the base station. This base station is a shared base station. This may only be part of the transmitter and receiver of the shared base station shared between the upper cell (or upper sector) and the ground cell (or ground sector). The advantages of a shared base station are self-evident. These benefits include extended coverage, cost savings, frequency resource savings, and immunity to interference.

4B illustrates another embodiment of a shared base station of the present invention. Unlike the antenna used as the transmit and receive antenna in FIG. 4A, separate transmit and receive antennas are used in the shared base station of FIG. 4B. The uptilt antenna 10t of the upper sector (or the upper cell) and the downtilt antenna 1t of the ground sector (or the ground cell) are coupled to each other via the splitter / combiner 30 (or coupler) so that the RF cable 4 Connected to the shared transmitter of the BTS 5 via the uptilt antenna 10r of the upper sector (or upper cell) and the downtilt antenna 1r of the ground sector (or ground cell) to the other splitter / combiner 30. It is coupled to each other via a (or coupler) and connected via RF cable 4 to the shared receiver of the BTS 5. In this embodiment, the antennas 10t and 1t function as transmit antennas, and the antennas 10r and 1r function as receive antennas. Antennas 10t, 1t have approximately the same uptilt angle and approximately the same coverage range within the upper sector (or upper cell), while antennas 10r, 1r have approximately the same downtilt angle within the ground sector (or ground cell). Have the same coverage range.

In the situation shown in Figures 4A and 4B, the upper sector (or upper cell) covered by the uptilt antenna and the ground sector (or ground cell) covered by the downtilt antenna are one sector (or cell) having a 3D spatial coverage range. Can be considered. The upper sector (or upper cell) is the expansion of the ground sector (or ground cell) in the space above the ground surface. No switching occurs when the subscriber station moves between these sectors. For example, when a person talking on a mobile phone moves from the first floor to the top floor of one of the skyscrapers 20 in FIG. 4A, the wireless communication line of the phone call is disconnected between that person's mobile phone and the BTS 5. Will remain.

Another solution to eliminate the interference between the upper cellular network and the terrestrial cellular network is to use a dedicated cellular frequency or frequency spectrum in the upper cellular network within a particular area. For example, some spare cellular frequency channels that were not used in existing mobile cellular systems may be used as dedicated cellular frequencies in the upper cellular network. In this solution, the upper cellular network may be independent of the terrestrial cellular network. The base station of the upper cell may be located at any preferred place within that particular area. This base station need not be arranged side by side with the base station of the ground cell. The upper cellular network may adopt different cellular network structures and frequency reuse schemes. For example, the upper cellular network may adopt the 4/12 frequency reuse plan, while the terrestrial cellular network may employ the 7/21 frequency reuse plan. The upper cellular network may share a system control center of the terrestrial cellular network or may have its own system control center.

The two methods described above can be flexibly integrated in one cellular to achieve maximum efficiency in terms of cost efficiency and coverage. That is, some upper cells share the base station and the system control center with the ground cell, and some other upper cells have their own base station and system control center or share the ground cell and system control center.

2A also shows an embodiment for the upper sector to use a dedicated frequency or frequency spectrum at its base station.

Figure 2B also shows an embodiment for the upper sector to use a dedicated frequency or frequency spectrum at its base station.

4C shows another embodiment where a dedicated frequency or frequency spectrum is used at the base station of the upper cell. In FIG. 4C, the base station of the upper sector and the base station of the ground sector are arranged side by side. A dedicated frequency or frequency spectrum is used for the BTS4 15 of the upper sector. The uptilt sector antenna 10 of the upper sector is connected to the BTS4 15 via an RF cable 4. The down tilt sector antenna 1 of the ground sector is connected to the BTS1 5 via an RF cable 4. All of these antennas are installed in the pillar 3. Arrow 51 represents the beam (or main) axis. Antenna 1 and antenna 10 function as transmit and receive antennas, respectively. In FIG. 4C, the BTS4 15 of the upper sector and the BTS1 5 of the ground sector are independent of each other. They operate at different cellular frequencies or frequency spectrums.

5A-5D illustrate embodiments of the integration of a system of an upper cellular network with a system of a terrestrial cellular network of this system.

The upper cellular network of the present invention further comprises at least one control center (eg, a switching center). It controls the communication of the upper cellular network and other systems such as terrestrial cellular networks and public switched telephone networks (PSTNs). The upper cellular and terrestrial cellular networks can share a common control center.

5A illustrates an embodiment of a system of the upper mobile cellular network of the present invention. In FIG. 5A, seven upper cells 21a, 21b, 21c, 21d, 21e, 21f, and 21g constitute one upper mobile cellular network. The upper cell 21a is divided into three upper sectors 22a1, 22a2, and 22a3, and the upper cell 21c is divided into three upper sectors 22c1, 22c2, and 22c3. The upper cell 21d is not a complete cell. This cell contains only two upper sectors 22d1, 22d3. The upper cell 21e is not a complete cell. This cell contains only one upper sector 22e1. The upper cell 21f is not a complete cell. This cell contains only one upper sector 22f1. The upper cells 21b and 21g are not divided into sectors. Each of these cells may be covered by one uptilt omnidirectional antenna. Each of the upper cells has a BTS at approximately the center of the cell. These are BTSs 15a, 15b, 15c, 15d, 15e, 15f, and 15g, respectively. The base station control center (BSC1) 25a is connected to the BTSs 15a, 15e, 15f, of the respective upper cells 21a, 21e, 21f, and 21g via the medium 27 (cable, optical fiber, microwave radio, etc.). And 15g). The BSC2 25b controls the BTSs 15b, 15c, and 15d of the respective upper cells 21b, 21c, and 21d through the medium 27. MSC 24 controls BSC1 25a and BSC2 25b via medium 26 (cable, fiber, microwave radio, etc.). It is also connected to the PSTN. The structure and operation of the upper mobile cellular network is similar to the existing terrestrial cellular system, except that the above ground cells and sectors are replaced by upper cells and sectors. The method of operation of this system is well known and is not within the scope of the present invention.

5B illustrates an embodiment of the integration of an upper mobile cellular network with a terrestrial mobile cellular network. As shown in Figure 5B, the dashed lines and circles represent the ground mobile cellular network, and the solid lines and circles represent the upper mobile cellular network. These are integrated together. The terrestrial mobile cellular network includes seven terrestrial cells 11a, 11b, 11c, 11d, 11e, 11f and 11g. Each terrestrial cell has a BTS approximately in its center. These are BTSs 5a, 5b, 5c, 5d, 5e, 5f, and 5g, respectively. BSC1 25a controls terrestrial cells 11a, 11e, 11f, and 11g via medium 27. BSC2 25b controls terrestrial cells 11b, 11c, and 11d via medium 27. MSC 24 controls BSC1 25a and BSC2 25b via medium 26. Each ground cell is divided into three ground sectors. For example, the ground cell 11d is divided into ground sectors 12d1, 12d2, and 12d3. The upper mobile cellular network comprises five upper cells 21a, 21b, 21c, 21f, 21g. The upper cell 21a is divided into three upper sectors 22a1, 22a2, and 22a3, the upper cell 21b is divided into three upper sectors 22b1, 22b2, and 22b3, and the upper cell 21g is It is divided into three upper sectors 22g1, 22g2, and 22g3. The upper cell 21c is not a complete cell. This cell contains only two upper sectors 22c1 and 22c3. The upper cell 21f is also not a complete cell. This cell contains only one upper sector 22f1. In this embodiment, each upper cell shares a common BTS with the ground cell. The upper cell 21a shares the BTS 5a of the ground cell 11a, the upper cell 21b shares the BTS 5b of the ground cell 11b, and the upper cell 21c is the ground cell 11c. ) Share the BTS 5c, the upper cell 21f shares the BTS 5f of the ground cell 11f, and the upper cell 21g shares the BTS 5g of the ground cell 11g. Thus, the upper mobile cellular network likewise shares the BSC1 25a, BSC2 25b and MSC 24 of the terrestrial mobile cellular network. This embodiment illustrates a situation where an uptilt antenna is coupled with an antenna of a terrestrial cell and / or terrestrial sector to share the BTS of some terrestrial cell and / or terrestrial sector in a mobile cellular system (shown in FIG. 4A). This is the most cost-effective way to extend the coverage of mobile cellular networks to the upper floors of skyscrapers. The method of operation of this system is well known and is not within the scope of the present invention.

5B also illustrates an embodiment of a shared base station and method for avoiding interference between the upper cellular network and the terrestrial cellular network.

5C illustrates an embodiment of the integration of a top mobile cellular system with a land mobile cellular system. As shown in Figure 5C, the dashed lines and circles represent ground mobile cellular networks, and the solid lines and circles represent top mobile cellular networks. These are integrated together. The terrestrial mobile cellular network includes seven terrestrial cells 11a, 11b, 11c, 11d, 11e, 11f and 11g. Each terrestrial cell has a BTS approximately in its center. These are BTSs 5a, 5b, 5c, 5d, 5e, 5f, and 5g, respectively. BSC1 25a controls terrestrial cells 11a, 11e, 11f, and 11g through the medium. BSC2 25b controls terrestrial cells 11b, 11c, and 11d through the medium. MSC1 24a controls BSC1 25a and BSC2 25b through the medium. Unlike in FIG. 5B, there is no sharing of BTS, BSC and MSC between the top cell and the ground cell in FIG. 5C. The upper mobile cellular network comprises three upper cells 21a, 21b, 21c. Each of the upper cells is located approximately near the boundary of the ground cell. The upper cell 21a is not a complete cell. This cell contains two upper sectors 22a1 and 22a3. The upper cell 21b is free of sectors. This may be covered by an uptilt omnidirectional antenna. The upper cell 21c is divided into three upper sectors 22c1, 22c2, and 22c3. Each of the upper cells has a BTS at its center approximately in the azimuth direction. These are the BTSs 15a, 15b and 15c, respectively. BSC3 25c controls the BTSs via medium 27. The upper mobile cellular network has its own control center MSC2 24b. This controls the BSC3 25c through the medium 26. The MSC 24b is also connected to the PSTN. In this embodiment, the upper mobile cellular system is independent of the ground mobile cellular system.

FIG. 5C also shows an embodiment of a method for avoiding interference between an upper cellular network and a terrestrial cellular network by using a dedicated frequency or frequency spectrum in the upper cellular network. In FIG. 5C, dedicated frequencies are used for the upper cells 15a, 15b, 15c to avoid interference with terrestrial cellular networks.

5D illustrates an embodiment for more complex integration of a top mobile cellular system with a land mobile cellular system. This is a combination of the integrated embodiments in FIGS. 5B and 5C. That is, some upper cells and upper sectors share BTSs, BSCs, and MSCs of ground cells, ground sectors, and terrestrial cellular networks, and some upper cells and upper sectors have their own BTSs, BSCs, and MSCs. In FIG. 5D, the upper cell 21s shares the BTS 5b of the ground cell 11b. This includes two upper sectors 22s1 and 22s3. The upper cell 21t shares the BTS 5c of the ground cell 11c. It comprises two upper sectors 22t1, 22t3. The upper cells 21s and 21t share the BSC2 25b and the MSC1 24a of the land mobile cellular network. On the other hand, each of the upper cells 21a, 21b, 21c has its own BTS near the boundary of the ground cell. These are the BTSs 15a, 15b and 15c, respectively. They also have their own BSC3 (25c) and MSC2 (24b). The upper cells 21a, 21b, 21c, 21s, 21t constitute the upper mobile cellular network. This embodiment is flexible and cost effective in extending the coverage of a mobile cellular system to space above the ground surface.

5D illustrates an embodiment of a combination of a method of avoiding interference by sharing a base station between an upper cell and a terrestrial cell and a method of avoiding interference by using a dedicated frequency or frequency spectrum in the upper cellular network. In FIG. 5D, dedicated frequencies are used in the upper cells 21a, 21b, 21c to avoid interference with terrestrial cells.

In the case of a CDMA mobile cellular system, the spread spectrum of the ground cell can be reused in the upper cell when base stations of the upper cell and the ground cell are not arranged side by side. In this case, the upper cell functions spatially as an adjacent cell of the ground cell. For example, in FIG. 5C, if the mobile cellular system is a CDMA system, the upper cells 21a, 21b, 21c may reuse the spread spectrum of the terrestrial cell. In addition to functioning as the adjacent cells of the upper cells 21a and 21c, the upper cell 21b functions as an adjacent cell of the ground cells 11a, 11b and 11g in the space on the ground surface. In a 3D cellular network, adjacent cells should be considered in 3D perspective.

A typical base station sector antenna has a wide azimuth and a small altitude beam pattern, which is well suited for terrestrial sector coverage. 6A shows a typical base station sector antenna, its beam pattern, and coverage. Sector antenna 31 comprises a set of radiating elements (eg, dipoles) aligned in a vertical plane. This produces a beam 33 whose azimuth beamwidth φ (eg 45 °) is much larger than the altitude beamwidth θ (eg 10 °). The beam 33 cannot cover the entire skyscraper when the antenna 33 is close to the skyscraper 20 (eg 500 meters), even if it is up tilted. The coordinate XYZ is shown as a reference (the Y axis represents the altitude direction, and the X axis and the Z axis represent two vertical directions in the horizontal plane).

Skyscrapers are not everywhere. They are concentrated in the small central shopping districts of the city and are scattered in large urban areas. Perhaps there are very few skyscrapers to be covered within a certain area. In urban mobile cellular systems, the cell size is small and many cellular base stations are close to skyscrapers. The base station antenna can concentrate its coverage in each skyscraper without covering the entire upper cell. Doing so will concentrate antenna radiation in some cell space rather than the cell as a whole, resulting in greater cellular signal strength and less interference with cellular networks in high-rise buildings, which will benefit system performance.

The present invention provides another method for cellular signal coverage in tall buildings in a mobile cellular system. This method is to install a narrow beam antenna at the base station of the mobile cellular system where the beam has a higher altitude beamwidth than the azimuth beamwidth. This antenna is connected to the BTS of the base station. The antenna emits cellular signals generated by the BTS in a high altitude but narrow azimuth beam pattern and directs the beam to a nearby skyscraper. To avoid interference, the beam is tilted upwards, or a dedicated cellular frequency or frequency spectrum is used at the base station. This solution is useful to cover one skyscraper or a group of skyscrapers adjacent to each other within a short distance.

6B shows an embodiment of the antenna and the method. Antenna 34 includes a set of radiating elements 35 (eg, dipoles) that are aligned in a horizontal plane. This antenna generates a beam 36 whose altitude beamwidth θ (eg 45 °) is much larger than its azimuth beamwidth φ (eg 10 °). It is tilted up at an angle α (eg 30 °) to cover the skyscraper 20. Coordinates XYZ are shown as a reference. Antenna 34 can be easily implemented. Rotating the antenna 31 of FIG. 6A by 90 ° about the X axis results in the antenna 34 of FIG. 6B. The antenna 34 is suitable for the coverage of individual skyscrapers or small groups of skyscrapers within a short distance.

7A-7F illustrate a new type of multibeam multitilt antenna that can be used to cover the top cell (or top sector) and the ground cell (or ground sector) with one antenna.

Since the antenna installation space is limited in the base station and the number of antennas to be installed in the antenna support structure is large, it is desirable that the antenna have multiple functions. Multi-function antennas are economical in addition to saving space. For this reason, a new type of multibeam multitilt has been devised that covers both the ground cell (or ground sector) and the upper cell (or upper sector) with one antenna. The antenna comprises at least two sets of radiating elements, support devices and beam tilt means. Each set of radiating elements comprises at least two radiating elements. Each set of radiating elements is installed in the support device spaced apart from each other. This antenna also includes an installation structure, a housing, and signal input / output port (s). The radiating element set, the support device and the beam tilting means are arranged in the housing. The first set of radiating elements generates a first beam in a first direction, and the second set of radiating elements generates a second beam in a second direction different from the first direction. The beam tilting means includes mechanical means, or electrical means, or both means for tilting each beam in a predetermined direction. This antenna therefore provides wireless signal coverage in two directions. Each beam may be omni or directional. The first and second sets of radiating elements may operate in the same mobile cellular frequency band, or in different mobile cellular frequency bands that do not overlap entirely. The polarity of the first beam and the polarity of the second beam may be the same or different from each other. The angle between the two beams is between 3 ° and 60 °. In the present invention, when the antenna is used for a cellular base station, the first beam is directed downward and the second beam is directed upward. Thus, this covers both the ground cell (or ground sector) and the upper cell (or upper sector) with one antenna.

FIG. 7A illustrates an embodiment of the multibeam multitilt of the present invention having a single cellular frequency band and vertical polarity. 7B shows the grove pattern at altitude. The double beam double tilt antenna 38 includes two sets of radiating elements 39 (above the dotted lines) and 40 (under the dotted lines). These two sets of radiating elements have vertical polarity and operate in the same frequency band (eg 800 MHz cellular frequency band). The radiating element set 39 comprises four radiating elements spaced apart from each other and installed in a support device (eg, ground plane). This produces a beam 37a that is uptilted at an angle α (eg 10 °) above the horizontal plane. Arrow 51a represents the axis of the beam 37a. Arrow 51b represents the axis of the beam 37b. Beams 37a and 37b each have approximately the same characteristics in the transmit and receive directions. The port 41 is an RF signal input / output unit of the antenna. The tilt of each beam can be implemented mechanically or electrically, or in two ways.

FIG. 7E illustrates an embodiment of electrical means for tilting each beam of antenna 38 in FIG. 7A in a given direction. The four radiating elements 39a, 39b, 39c, 39d of the set 39 are provided in the grounded supporting plate 47 at approximately equal intervals. Four radiating elements 40a, 40b, 40c, 40d of the set 40 are also provided on the support plate 47 at approximately equal intervals. The support plate 47 has a substantially vertical direction. Reference numeral 50a denotes a signal feeding circuit of the set 39. It is connected to port 41 via divider 49 (which divides the signal evenly or unevenly). The supply circuits of the radiating elements 39a, 39b, 39c, 39d increase in length in stages. Thus, their phases increase in stages (e.g., starting at element 39a, the phase increases to δ in element 39b, to 2δ in element 39c, and to 3δ in element 39d). Increases). Thus, the beam generated by the set 39 is down tilted (down tilt angle depends on the frequency and phase shift step δ). Reference numeral 50b denotes a signal feeding circuit of the set 40. It is connected to port 41 via divider 49. The supply circuits of the radiating elements 40a, 40b, 40c, and 40d increase in length in stages. Thus, their phases increase in stages (e.g., starting at element 40a, the phase increases to γ in element 40b, increases to 2γ in element 40c, and 3γ in element 40d). Increases). Thus, the beam generated by the set 40 is uptilted (the uptilt angle depends on the frequency and phase shift stage γ). The inner back surface of the housing 45 is provided with a reflecting plate 46 for reflecting the radiation signal again. The radiating elements, the supporting plate 47, the power feeding circuits 50a and 50b, the divider 49 and the reflecting plate 46 are installed in the housing interior 45. The mounting structure is attached to the outer backside of the housing 45 (not shown in the figure). Thus, the antenna of FIG. 7E generates an uptilt beam and a downtilt beam. This is a single band double beam double tilt base station sector antenna.

FIG. 7C illustrates an embodiment of the multibeam multitilt of the present invention having a dual cellular frequency band and cross polarity. 7D shows the grove pattern at altitude. The double beam double tilt antenna 42 includes two sets of radiating elements 43 (above the dotted lines) and 44 (under the dotted lines). These two sets of radiating elements have cross polarity. Set 43 operates in a first frequency band (eg, 800 MHz cellular frequency band) and set 44 operates in another frequency band (eg, 1900 MHz cellular frequency band). The set 43 includes four radiating elements spaced apart from one another and installed in a support device (eg, ground plane). This generates a beam 37d down tilted at an angle β (eg 8 °) below the horizontal plane. The set 44 includes four radiating elements spaced from each other and installed in the support device. This generates a beam 37c which is up tilted at an angle α (eg 10 °) above the horizontal plane. Arrow 51c represents the axis of the beam 37c. Arrow 51d indicates the axis of the beam 37d. The beams 37c and 37d have approximately the same characteristics in the transmitting and receiving directions, respectively. The port 41a is an RF signal input / output unit of the set 43. The port 41b is an RF signal input / output unit of the set 4. The tilt of each beam can be implemented mechanically or electrically, or in two ways.

FIG. 7F illustrates an embodiment of the mechanical means for tilting each beam of antenna 42 in FIG. 7C in a given direction. Set 43 includes four radiating elements 43a, 43b, 43c, 43d. They are provided at approximately the same intervals on the grounded support plate 47a. The support plate 47a is down tilted at an angle β from the vertical direction. Set 44 includes four radiating elements 44a, 44b, 44c, 44d. They are provided at approximately the same intervals on the grounded support plate 47b. The support plate 47b is up tilted at an angle α from the vertical direction. Reference numeral 48a denotes a signal feeding circuit of the set 43. It is connected to port 41a. The supply circuit of each radiating element is approximately equal in length and phase. Thus, the set 43 generates a beam in the direction passing through the support plate 47a. Reference numeral 48b denotes a signal feeding circuit of the set 44. It is connected to port 41b. The supply circuit of each radiating element is approximately equal in length and phase. Thus, the set 44 generates a beam in a direction penetrating the support plate 47b. The inner back surface of the housing 45 is provided with a reflecting plate 46 for reflecting the radiation signal again. The mounting structure is attached to the outer backside of the housing 45 (not shown in the figure). Reference numeral 49 denotes a divider in the power supply circuit. The radiating elements, the support plates 47a and 47b, the power feeding circuits 48a and 48b, and the reflecting plate 46 are provided in the housing interior 45. Therefore, the antenna of FIG. 7F generates the beamdown tilt angle β and the beamup tilt angle α. This is a dual band double beam double tilt base station sector antenna.

The multibeam multitilt antenna of the present invention can be applied to a base station of a mobile cellular system to provide 3D spatial coverage. In this application, the multibeam multitilt antenna is connected to the BTS of the base station. One beam is directed downward to cover the ground cell (or ground sector) and the other beam is directed upward to cover the upper cell (or upper sector). Thus, this base station provides 3D spatial coverage. For example, the single band dual beam double tilt antenna 38 of FIG. 7A can be used to replace antenna 1, antenna 10 and divider / combiner (or coupler) 30 in FIG. 4A. The port 41 is connected to the BTS 5. One beam is directed downward and the other beam is directed upward to cover both the ground sector and the upper sector. In this application, the antenna 38 functions as an integrated uptilt antenna 10 and downtilt antenna 1. As another example, the dual band dual beam double tilt antenna 42 of FIG. 7C can be used to replace antenna 1 and antenna 10 of FIG. 4C. Port 41a is connected to BTS1 5 of the ground sector and port 41b is connected to BTS4 15 of the upper sector. Antenna 42 covers the ground sector with the beam generated by BTS1 5 pointing downward. Antenna 42 covers the upper sector with the beam generated by BTS4 15 facing upwards. Thus, this antenna covers both the ground sector and the upper sector.

What has been achieved by the present invention is a cost-effective solution for providing cellular signal coverage in skyscrapers in mobile cellular systems. The networks, methods, base stations and antennas of the present invention may be used in other cellular communication systems to provide cellular signal coverage in the surface and in the space above the surface.

In the foregoing description, although completes with known equivalents are described, such equivalents are included herein as if individually described.

Although the present invention has been described by way of example, various modifications and changes can be made without departing from the scope and spirit of the invention. For example, antenna spatial diversity, particularly at base stations in the uplink, is a common method used for terrestrial cells and sectors to overcome multipath fading and improve system performance of mobile communication systems. This may be implemented at the base station of the upper cell and the upper sector for the same purpose. It is to add an uptilt spatial diversity antenna for an uptilt antenna at the base station of the upper cell (or upper sector). As another example, the uptilt antenna and the downtilt antenna sharing the BTS at the base station may be configured as one integrated antenna providing the same function as the antenna 38 of FIG. 7A.

Claims (26)

In the cellular communication network for providing a cellular communication service in a specific area divided into a plurality of cells, A plurality of base stations, each providing a radio signal to a subscriber station in an associated cell of any of said cells, At least one first base station of the base stations, A transmitter for generating a first radio signal to be provided in a first cell of the cells associated with the first base station within a frequency range that can be reused in one or more of the cells; A first antenna coupled to the transmitter for radiating the first wireless signal in a radiation characteristic pattern with a primary directed downward; And A second antenna coupled to the transmitter for radiating the first wireless signal in a radiation characteristic pattern with a primary directed upward; Radiating the first radio signal under the first antenna and over the second antenna into the first cell, wherein the first radio signal may interfere with radio signals from other base stations of the base stations. A cellular network that prevents radiation to other cells of the cells. The cellular network of claim 1, wherein the first base station further comprises a receiver for receiving a radio signal generated by a subscriber station in the first cell. 3. The receiver of claim 2, wherein the receiver is coupled to the first and second antennas for receiving the radio signal generated by a subscriber station in the first cell via at least one of the first and second antennas. Cellular network. The cellular communication network according to claim 1, wherein the first and second antennas are arranged substantially side by side. 5. The cellular communication network as claimed in claim 1, wherein the first antenna is above the second antenna at a height. 6. The cellular communication network according to any one of claims 1 to 5, wherein the first antenna and the second antenna are integrally formed. The method according to any one of claims 1 to 6, wherein the second one of the base stations, A second base station transmitter for generating a second base station radio signal to be provided in a second cell of the cells associated with the second base station within a frequency range that can be reused in one or more of the cells; And A second base station antenna coupled to the second base station transmitter for radiating the second base station radio signal in a radiation characteristic pattern with a primary facing upwards; Radiating said second base station radio signal over said second base station antenna into said second cell, wherein said second base station radio signal may interfere with radio signals from other base stations; Cellular network that prevents radiation to cells. 8. The cellular network of claim 7, wherein the second base station further comprises a receiver for receiving a radio signal generated by a subscriber station in the second cell. A method for providing a cellular communication service in a specific area divided into a plurality of cells, the method comprising: Generating a plurality of radio signals each having a frequency range provided to a subscriber station in any associated cell of said cells and reusable in at least one of said cells; And Providing each of said wireless signals to an associated cell, The first wireless signal of the wireless signals, Radiating the first wireless signal from a first antenna in a radiation characteristic pattern with a main facing downward; and By radiating the first radio signal from the second antenna in a radiation characteristic pattern with the main facing upwards Provided to a first cell of said cells associated with said first wireless signal, Radiating the first radio signal under the first antenna and over the second antenna into the first cell, wherein the first radio signal may interfere with other radio signals of the plurality of radio signals; A method of providing a cellular communication service that prevents radiation to other cells. 10. The method of claim 9, further comprising receiving at the first cell at least one radio signal from a subscriber station. The method of claim 10, wherein the at least one radio signal is received through at least one of the first and second antennas. 12. The method of any one of claims 9 to 11, wherein the first and second antennas are disposed substantially side by side. 13. The method of any one of claims 9 to 12, wherein the first antenna is above the second antenna in height. The method of any one of claims 9 to 13, wherein the first antenna and the second antenna are integrally formed. The method according to any one of claims 9 to 14, wherein the second one of the wireless signals, By radiating the second radio signal from the second cell antenna in a radiation characteristic pattern with the primary facing upwards Provided to a second one of said cells associated with said second wireless signal, Radiating the second radio signal onto the second cell antenna into the second cell, wherein the second radio signal radiates to other ones of the cells that may interfere with other radio signals of the plurality of radio signals. How to provide cellular communication services to prevent A base station of a cellular communication network for providing a plurality of cellular radio signals to a specific area divided into a plurality of cells, A transmitter for generating a transmitter radio signal to be provided in a first cell of said cells, said transmitter operating within a frequency range reusable in one or more of said cells; A first antenna coupled to the transmitter for radiating the transmitter radio signal in a radiation characteristic pattern with a primary facing downward; And A second antenna coupled to the transmitter for radiating the transmitter radio signal in a radiation characteristic pattern with a primary facing upwards; Radiating the transmitter radio signal below the first antenna and above the second antenna into the first cell, wherein the transmitter radio signal may interfere with other radio signals of the plurality of radio signals; A base station that prevents radiation to other cells. 17. The base station of claim 16, further comprising a receiver for receiving a radio signal generated by a subscriber station in the first cell. 17. The apparatus of claim 16, wherein the receiver is coupled to the first and second antennas for receiving the wireless signal generated by a subscriber station in the first cell via at least one of the first and second antennas. Base station. 19. The cellular communication network according to any one of claims 16 to 18, wherein the first antenna and the second antenna are integrally formed. A base station antenna operating in a frequency range for cellular communication, A first set of radiating elements comprising at least two radiating elements spaced apart from each other, operable in a first frequency range, the first set of radiating elements having a radiation characteristic pattern in a first direction; A second set of radiating elements comprising at least two radiating elements spaced apart from each other, operable in a second frequency range, the second set of radiating elements having a radiation characteristic pattern in a second direction; And Means for tilting the first main lobe in the first direction and the second main lobe in the second direction, The angle between the first direction and the second direction is between 3 ° and 60 °, The base station antenna has a base station antenna having a radiation characteristic pattern in which two main waves are in two directions. 21. The base station antenna of claim 20 wherein the first frequency range and the second frequency range are the same. 23. The base station antenna of claim 21, wherein the first and second sets of radiating elements can be driven by the same radio station. 21. The base station antenna of claim 20, wherein the first frequency range and the second frequency range do not fully overlap. 24. The base station antenna of claim 23, wherein the first set of radiating elements can be independently driven by a first radio station, and the second set of radiating elements can be independently driven by a second radio station. The base station antenna as claimed in claim 20, wherein the base station antenna is a sector antenna. 25. The base station antenna of any one of claims 20 to 24, wherein the base station antenna is an omnidirectional antenna.