JP3681730B2 - Repeater device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a repeater device used for wireless communication by a code division multiple access (CDMA) system.
[0002]
[Prior art]
Repeater devices (also called relay devices or wireless relay boosters) are used to improve the radio wave conditions in buildings, tunnels, or mountainous areas where radio base station radio waves are difficult to reach. Since this repeater device basically amplifies and transmits the received radio wave, there is no need to lay a dedicated line like a forward base station, and there is an advantage that the equipment cost can be reduced (for example, Patent Documents) 1). In some cases, the relay area is divided into a plurality of sectors, and a directional antenna pattern corresponding to each sector is generated.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-196994
[Problems to be solved by the invention]
However, in the conventional repeater apparatus described above, even if a directional antenna pattern corresponding to each sector is generated, a null is generated in the overlapping area by combining the antenna patterns near the boundary of each antenna pattern. There is a problem that the sexual pattern is disturbed and adversely affects the stability of communication.
[0005]
The present invention has been made in consideration of such circumstances, and an object of the present invention is a repeater apparatus used for wireless communication by a code division multiple access system, which can improve communication stability. To provide an apparatus.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a repeater apparatus according to claim 1 is a repeater apparatus that is used for wireless communication by a code division multiple access method and relays a received signal to a wireless station having a rake reception function. A first antenna, a plurality of second antennas corresponding to each sector in the relay area, each of which forms an antenna pattern having a different directivity, and a received signal received from the first antenna. Of a spread signal in the code division multiple access method between a relay means that relays and outputs a transmission signal from the plurality of second antennas and a transmission signal output by an antenna pattern adjacent to the second antenna. And a delay means for providing a delay time difference equal to or greater than that of the chip.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration example of a mobile communication system using a repeater device 2 according to an embodiment of the present invention. This mobile communication system performs multiple access between a base station and a mobile station by a CDMA system. In FIG. 1, a repeater device 2 receives radio waves from a base station 1 by a base station antenna 21 in a downlink from the base station 1 to the mobile station 3, amplifies it to a predetermined level, The signal is re-radiated from the mobile station antennas 22-1 and 22-2 toward an area where radio waves do not reach. Here, the repeater apparatus 2 generates a directional antenna pattern corresponding to each sector in the relay area. In the example of FIG. 1, antenna patterns 101 and 102 are generated by two mobile station antennas 22-1 and 22-2, respectively. The antenna patterns 101 and 102 overlap in the area 103.
[0009]
On the other hand, in the uplink from the mobile station 3 to the base station 1, the radio wave from the mobile station 3 is received by the mobile station antenna 22-1 or 22-2, amplified to a predetermined level, and the base station antenna 21 is received. Re-radiate from. This implements a bidirectional relay function between the base station and the mobile station in the uplink and downlink.
[0010]
FIG. 2 is a block diagram showing a configuration of the repeater device 2 according to the first embodiment of the present invention. In FIG. 2, the repeater device 2 includes a base station antenna 21, two mobile station antennas 22-1 and 22-2, a master station side device 30, and two slave station side devices 40-1 and 40-2. Composed. The master station side device 30 and the slave station side devices 40-1 and 40-2 correspond to the relay means.
[0011]
The master station side device 30 is a device facing the base station, and is connected to the base station antenna 21. Each of the slave station side devices 40-1, 40-2 is a device facing the mobile station, and is connected to one of the two mobile station antennas 22-1, 22-2. Each of the slave station side devices 40-1 and 40-2 is connected to the master station side device 30.
[0012]
The master station side device 30 includes an antenna transmission / reception duplexer (DUP) 31, a low noise amplifier (LNA) 32, a transmission power amplifier (PA) 33, a distributor 34, a combiner 35, and a delay device 36. The DUP 31 is connected to the base station antenna 21. The slave station side devices 40-1 and 40-2 are composed of a PA 41, an LNA 42, and a DUP 43. The DUP 43 of one slave station side device 40-1 is connected to the mobile station antenna 22-1. The DUP 43 of the other slave station side device 40-2 is connected to the mobile station antenna 22-2.
[0013]
Next, the operation of the repeater device 2 shown in FIG. 2 will be described.
First, in the downlink from the base station 1 to the mobile station 3, radio waves from the base station 1 are received by the base station antenna 21, and this received signal is input to the LNA 32 via the DUP 31 of the master station side device 30. The The LNA 32 amplifies the input received signal and outputs it. The distributor 34 distributes and outputs the output signal of the LNA 32 to the slave station side device 40-1 and the delay device 36. The delay device 36 delays the input signal by a predetermined time and then outputs it to the slave station side device 40-2.
[0014]
The PA 41 of the slave station side device 40-1 amplifies the signal input from the master station side device 30 and outputs the amplified signal to the mobile station antenna 22-1 via the DUP 43. Thereby, the radio wave from the base station is re-radiated from the antenna for mobile station 22-1 by the antenna pattern 101 of FIG. The PA 41 of the slave station side device 40-2 amplifies the signal input from the master station side device 30 and outputs the amplified signal to the mobile station antenna 22-2 via the DUP 43. Thereby, the radio wave from the base station is reradiated from the antenna 22-2 for the mobile station by the antenna pattern 102 of FIG.
[0015]
Here, the radio wave from the mobile station antenna 22-2 is radiated by a delay time in the delay device 36 from the radio wave from the mobile station antenna 22-1. The delay time in the delay device 36 is set to be equal to or longer than the time of one element (chip) of the spread signal (PN code) in the CDMA system. For example, in the IS-95 base CDMA system, it is set to 813.8 nanoseconds or more.
[0016]
A mobile station based on the CDMA system has a rake reception function. If the difference in arrival times of multipath signals is equal to or longer than the time of one chip, the multipath signals are separated and received. The reception characteristics can be improved by combining them. With this rake reception function, the mobile station 3 in the overlapping area 103 of FIG. 1 receives the signal from the antenna pattern 101 radiated from the mobile station antenna 22-1 and the antenna radiated from the mobile station antenna 22-2. The signal from the pattern 102 is separated and received, and further combined to perform subsequent reception processing. Thereby, the stability of communication improves.
[0017]
Next, in the uplink from the mobile station 3 to the base station 1, the radio wave from the mobile station 3 is received by the mobile station antenna 22-1 or 22-2. The received signal received by the mobile station antenna 22-1 is input to the LNA 42 via the DUP 43 of the slave station side device 40-1. The LNA 42 amplifies the input received signal and outputs it to the master station side device 30. On the other hand, the received signal received by the mobile station antenna 22-2 is input to the LNA 42 via the DUP 43 of the slave station side device 40-2, amplified by the LNA 42, and then the delay unit 36 of the master station side device 30. Is output. The delay device 36 delays the input signal from the slave station side device 40-2 for a predetermined time (set time equal to or more than one chip) and outputs the delayed signal to the combiner 35.
[0018]
The combiner 35 combines the input signal from the slave station side device 40-1 and the input signal from the delay device 36 and outputs the combined signal to the PA 33. The PA 33 amplifies the input signal and outputs the amplified signal to the base station antenna 21 via the DUP 31. Thereby, the radio wave from the mobile station is re-radiated from the antenna 21 for the base station.
[0019]
Here, the radio wave received by the mobile station antenna 22-2 is radiated with a delay of one chip or more from the radio wave received by the mobile station antenna 22-1. The base station 1 has a rake reception function and can separate the reception signal of the mobile station antenna 22-1 from the reception signal of the mobile station antenna 22-1.
[0020]
As described above, according to the first embodiment, when generating a plurality of antenna patterns having different directivities, the radiation timing of each antenna pattern is shifted by a time corresponding to one chip of a spread signal in the CDMA system. Thereby, when relaying the received signal from the base station to the base station, the mobile station in the overlapping area of the antenna pattern can receive the signal by each antenna pattern separately by the rake reception function, Communication stability is improved.
[0021]
In the first embodiment described above, the delay device 36 is provided in the master station side device 30, but the delay device 36 may be provided in the slave station side device 40-2. In this case, in the downlink, it may be provided before the PA 41 or may be provided after the PA 41. Further, in the uplink, it may be provided before the LNA 42 or may be provided after the LNA 42.
[0022]
Further, the delay device 36 (delay means) may be one that electrically adds a delay amount, or one that optically adds a delay amount. For example, an optical fiber cable having a cable length corresponding to the transmission time corresponding to the delay time is provided, and an input signal is configured to pass through the optical fiber cable and output.
[0023]
Next, a second embodiment will be described.
FIG. 3 is a block diagram showing a configuration of the repeater device 2 according to the second embodiment of the present invention. In FIG. 3, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 3, the repeater apparatus according to the second embodiment includes a basic unit (first relay unit) including a master station side apparatus and two slave station side apparatuses. Then, by extension, an extension unit (second relay means) including a master station side device and two slave station side devices is further provided. The expansion part can be increased or decreased. As a result, the system capacity can be easily expanded or reduced based on the increase or decrease of the number of users.
[0024]
The DUP 31 of the master station side device 30 of the extension unit is connected to the second polarization plane of the base station antenna 21. The DUP 43 of the slave station side device 40-1 of the extension unit is connected to the second polarization plane of the mobile station antenna 22-1. The DUP 43 of the slave station side device 40-2 of the extension unit is connected to the second polarization plane of the mobile station antenna 22-2. The base station antenna 21 has a first polarization plane and a second polarization plane orthogonal thereto. The basic unit uses the first polarization plane of the base station antenna 21. The extension unit uses the second polarization plane of the antenna 21 for the base station. The mobile station antennas 22-1 and 22-2 have a first polarization plane and a second polarization plane orthogonal to the first polarization plane. The basic unit uses the first polarization plane of the mobile station antenna 22-1 and the first polarization plane of the mobile station antenna 22-2. The extension unit uses the second polarization plane of the mobile station antenna 22-1 and the second polarization plane of the mobile station antenna 22-2.
[0025]
FIG. 4 is a diagram illustrating an example of transmission frequency band characteristics in the uplink of each of the basic unit and the extension unit of FIG. As shown in FIGS. 4A and 4B, the basic unit has the same transmission frequency band characteristics as the expansion unit in advance. In the example of FIG. 4, the basic unit and the extension unit have a relay function of four carriers, and the frequency band and characteristics of each carrier are the same in the basic unit and the extension unit. Thereby, the received signals of the four carriers from the mobile station are amplified by the basic unit and the extension unit and radiated to the base station.
[0026]
Here, paying attention to the reception signal of the mobile station antenna 22-1, the signal received at the first polarization plane is relayed to the base station via the basic section and received at the second polarization plane. The signal is relayed to the base station via the expansion unit. As a result, the base station can obtain a reception signal of the first polarization and a reception signal of the second polarization for a certain carrier, and performs diversity reception based on the reception signals of different polarizations. be able to. Similarly, with respect to the reception signal of the antenna 22-2 for the mobile station, reception signals with different polarizations are relayed to the base station, and diversity reception is possible at the base station. As a result, the uplink communication stability from the mobile station to the base station is improved.
[0027]
FIG. 5 is a diagram illustrating an example of transmission frequency band characteristics in the downlink of each of the basic unit and the extension unit of FIG. As shown in FIGS. 5A and 5B, the transmission frequency band characteristics are different between the basic part and the extension part. In the example of FIG. 5, the basic unit has a relay function for two carriers having a lower frequency, while the extension unit has a relay function for two carriers having a higher frequency. Thereby, in the downlink, the received signal from the base station is efficiently relayed to the mobile station.
[0028]
According to the second embodiment described above, since the reception signal relayed by the basic unit and the reception signal relayed by the extension unit are respectively received signals with different polarizations, the base station is based on the received signals with different polarizations. Diversity reception can be realized, and communication stability is improved. In addition, since the basic unit has the same transmission frequency band characteristics as the expansion unit in advance, there is no need to change the transmission frequency band characteristics of the basic unit to match the expansion unit when installing the expansion unit. It is possible to easily cope with an increase in the number of carriers.
[0029]
The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.
[0030]
【The invention's effect】
As described above, according to the first aspect of the present invention, when generating a plurality of antenna patterns having different directivities, the radiation timing of each antenna pattern is equal to or longer than the time of one chip of the spread signal in the CDMA system. Since they are shifted, a radio station (for example, a mobile station) in the overlapping area of these antenna patterns can separately receive signals from the respective antenna patterns by the rake reception function, thereby improving the stability of communication.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration example of a mobile communication system using a repeater device 2 according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a repeater device 2 according to the first embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a repeater device 2 according to a second embodiment of the present invention.
4 is a diagram illustrating an example of transmission frequency band characteristics in the uplink of each of the basic unit and the extension unit of FIG. 3;
5 is a diagram illustrating an example of transmission frequency band characteristics in the downlink of each of the basic unit and the extension unit of FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Base station, 2 ... Repeater apparatus, 3 ... Mobile station, 21 ... Base station antenna, 22-1, 22-2 ... Mobile station antenna, 30 ... Master station side apparatus, 31, 43 ... Antenna transmission / reception duplexer (DUP), 32, 42 ... low noise amplifier (LNA), 33, 41 ... transmission power amplifier (PA), 34 ... distributor, 35 ... combiner, 36 ... delay device

Claims (1)

A repeater device that is used for wireless communication by a code division multiple access method and relays a received signal to a wireless station having a rake reception function,
A first antenna;
A plurality of second antennas corresponding to each sector in the relay area and forming antenna patterns having different directivities for each antenna;
Relay means for relaying a reception signal received from the first antenna and outputting as a transmission signal from the plurality of second antennas;
Delay means for providing a delay time difference of one or more chips of a spread signal in a code division multiple access method between transmission signals output by adjacent antenna patterns of the second antenna;
A repeater device comprising:

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