Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
1999-09-01
2002-07-02
Maung, Nay (Department: 2681)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
C455S562100, C455S456500
Reexamination Certificate
active
06415161
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mobile communication system with transmitting systems with different outputting power.
2. Description of the Related Art
A Personal Handy-phone System (PHS), formerly known as Personal Handy Phone (PHP), employs a four-channel multiplex TDMA (Time Division Multiple Access)—TDD (Time Division Duplex) method. The four-channel TDMA method implies that four signals are arranged in time series (four bursts). The cell station can communicate with a maximum of four personal mobile stations by using the four-channel TDMA method.
In a mobile communicating system such as PHS, the apparatus for the cell station (CS) is required to be miniaturized, of light weight and low power consumption, since the apparatus of the cell station services an infrastructure. Especially, flexibility in the manner of installation of the cell station is extremely important for a PHS system needing a large number of cell stations. From this viewpoint, the apparatus of the cell station which is made smaller and lighter is required. The cell station is installed in various manners, and the cell station is installed on a public telephone box, a telephone pole, a wall of a building, a housetop and the like in the outdoors, and installed on a ceiling, a public telephone base and the like in an underground market, an underpass and a building.
When a cell station having a plurality of channels has a plurality of transmitters, output powers of the respective transmitters are set to values identical to each other. Thus, the power consumption of the cell station is increased in proportion to the number of transmitters which the cell station has (by integer multiples).
Especially when the cell station has a high-power outputting transmitter, the high-power outputting transmitter generates a large amount of heat. As a result, the high-power outputting transmitter requires increasing the number of fins and making a surface area wider to improve the heat radiation as the solution. This results in a problem that the apparatus of the cell station is made large in size and heavy. Hence, the cell station becomes more expensive to manufacture and further the flexibility in the manner of installation is impaired.
Moreover, a high-power outputting power amplifier is expensive in itself. Thus, if the number of high-power outputting transmitters is increased, the cost of the cell station is correspondingly made largely expensive.
Therefore, it is necessary to develop a small cell station apparatus in which the heat generation amount is dropped and to reduce the cost while the quality of communication service is kept in a conventional level.
In addition, the following techniques have been traditionally provided, with regard to the mobile communicating method and the cell station.
Japanese Laid-Open Patent Application (JP-A-Showa 62-82731) describes the following conventional mobile communicating method. When a plurality of kinds of personal mobile stations whose transmission powers are different from each other are in one service area (for example, in an automobile telephone, a personal mobile station which is fixed in a vehicle and has a large transmission power, and a personal mobile station having a small transmission power which is portable after a user gets off), a plurality of slave cell stations having small transmission powers are installed in a service area of a master cell station having a large transmission power.
The above-mentioned mobile communication method needs a plurality of master and slave cell stations in the one service area and the above-mentioned mobile communication method becomes expensive. Also, the above-mentioned mobile communication method has the premise that there are a plurality of kinds of personal mobile stations whose transmission powers are different from each other. Thus, the above-mentioned problems can not be solved.
Japanese Laid-Open Patent Application (JP-A-Heisei 7-177570) describes the following radio telephone apparatus. This radio telephone apparatus has both functions of a cellular mode and a PHP (Personal HandyPhone) mode in a single radio telephone apparatus and can switch between incoming and outgoing calls as a cellular type radio telephone apparatus if a user is not located within a PHP service area, or as a PHP type radio telephone apparatus if the user is located within the PHP service area.
The above-mentioned radio telephone apparatus has only a technique of giving the two-mode function to the single apparatus as the personal mobile station and then switching between the modes in accordance with a reception field strength. Thus this can not solve the problem of miniaturizing the apparatus of the cell station, decreasing the cost and reducing the heat generation.
Japanese Laid-Open Patent Application (JP-A-Heisei 10-23498) describes the following radio cell station, subscriber apparatus and operation method. This conventional example is provided with: a plurality of cell stations each containing a plurality of subscriber apparatuses; a hybrid section for integrating and treating signals, which are transmitted and received by the plurality of cell stations, between it and a single antenna; and a multiplexing/separating section for integrating and treating signals which are transmitted and received between the plurality of cell stations and an existing network, with regard to WLL (Wireless Local Loop) using PHS.
Japanese,Laid-Open Patent Application (JP-A-Heisei 5-292010) describes the following method and apparatus for assigning a radio channel. A radio zone is divided into concentric circles of the same area. A cell station is positioned at a center of each of the concentric circles. The number of cell stations is equal to the number of channels which can be used in a whole system. A channel is assigned to each region. In a case of an occurrence of a channel assignment request, the corresponding channel and the vicinity are preferentially assigned to the region at which the personal mobile station is located.
Japanese Laid-Open Patent Application (JP-A-Heisei 10-51380) describes the following CDMA (Code Division Multiple Access) system, an apparatus for controlling its transmission power and a DBF antenna. A side of a cell station has a non-directional antenna and a directional antenna. A non-directional antenna section has a transmitting/receiving unit for transmitting to M personal mobile stations. Each of them has a power measuring unit and a comparator with a first standard value. A directional antenna section has a transmitting/receiving unit so as to be connected to (N−M) personal mobile stations. Each of them has a power measuring unit and a comparator with a second standard value. Those two standard values are established in accordance with a ratio of a reception power to an interference power density.
Japanese Laid-Open Patent Application (JP-A-Heisei 6-311089) describes the following method for again using a frequency. A cell station has a plurality of call channels which are divided into an interior area call channel apparatus group and an exterior area call channel apparatus group. A service area of the cell station is logically divided into an interior area and an exterior area on a concentric circle in accordance with a predicted traffic. A minimum desirable wave level in an interior area call channel apparatus is kept higher than a minimum desirable wave level in an exterior area call channel apparatus.
Japanese Laid-Open Patent Application (JP-A-Heisei 4-47722) describes the following method for controlling a radio assignment in a mobile communication. At first, in a plurality of cell stations installed in a service area, the individual cell station has a first antenna for targeting a first radio zone and a second antenna for targeting a second radio zone. Here, the second radio zone is narrower in region than the first radio zone. Also, a vertical in-plane directivity of the second antenna is facing further downward from that of the first antenna. Each cell station is
Maung Nay
NEC Corporation
Trinh Sonny
Whitham Curtis & Christofferson, P.C.
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