JP2000253436A - Cdma radio base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the configuration for composing the received signals in an inter-sector handover state in a CDMA radio base station provided with plural sector antennas having directivity and capable of receiving signals modulated by a CDMA system and radio transmitted from a mobile station by these antennas and demodulating the received signals. SOLUTION: This CDMA radio base station is individually provided with non-handover signal processing parts B1a to B2a, B1b to B2b for demodulating a signal received by a single antenna in each of receiving parts S1a, S1b of respective sector antennas T1a, T1b and handover signal processing parts B3a, B3b capable of synthesizing signals at the time of demodulating signals received by plural antennas and control means 27a, 27b respectively detect an inter-sector handover state receiving the same signal radio transmitted from a mobile station by plural antennas and allow the handover signal processing parts B3a, B3b to demodulate and synthesize the received signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a plurality of sector antennas having directivity, and receives and demodulates a signal modulated by a CDMA (Code Division Multiple Access) system and wirelessly transmitted from a mobile station by the sector antenna. CDM to process
A radio base station, in particular, a CD having a simplified configuration for combining received signals at the time of handover between sectors
It relates to an MA radio base station.

[0002]

2. Description of the Related Art The CDMA system is used in the field of wireless communication such as mobile communication, and is known as a communication system having high confidentiality and high ability to eliminate interference waves. In this CDMA system, for example, an independent spreading code is assigned to each user (communication channel), and a transmitting side wirelessly transmits a signal modulated using the spreading code,
A correlation between a signal received by a receiving side and a spreading code (that is, despreading) is used to extract a desired signal and demodulate the signal.

For example, in a mobile communication system for performing wireless communication between a wireless base station (CDMA wireless base station) and a mobile station using the CDMA method, a CDMA wireless base station is installed in an area with a lot of traffic. By providing the radio base station with a plurality of directional sector antennas, it is possible to form a sector cell configuration in which an area (cell) communicable by the radio base station is divided into a plurality of communication areas (sectors). Have been done. In this sector cell configuration,
Since a sector is formed for each sector antenna having directivity provided in the CDMA radio base station, for example, in each sector antenna, the influence of interference waves in directions other than the directivity direction is reduced, and the frequency utilization efficiency is improved. be able to.

When such a sector cell configuration is used, a mobile station may move between communicable areas (sectors) of a plurality of sector antennas provided in a CDMA radio base station. CDMA
In the wireless base station, inter-sector handover processing is performed.
That is, at the time of such inter-sector handover, the same signal wirelessly transmitted from the mobile station is received by a plurality of sector antennas of the CDMA radio base station, and the same radio base station receives the same signal received by the plurality of sector antennas. A handover process between sectors for combining (diversity combining) signals is performed.

[0005] A configuration example of a CDMA radio base station that performs the above-described inter-sector handover processing will be described with reference to FIGS. 5 and 6. FIG. 5 shows a configuration example of such a CDMA radio base station.
An antenna unit 71 provided with a plurality of sector antennas for transmitting and receiving RF signals (radio frequency signals), and a transmission / reception amplification unit (AM) for amplifying an RF signal to be transmitted or a received RF signal
P) 72, a radio (RF) unit (TRX) 73 for converting a baseband signal to an RF signal or converting an RF signal to a baseband signal, and a baseband (BB) for performing baseband signal processing A wire transmission line interface (HWY INT) 75 for performing data conversion and the like between the baseband unit 74 and the wire transmission line;
For example, a radio base station control unit (CNT) 76 that transmits and receives control signals to and from a system control unit such as an MCC-SIM and manages a radio channel is provided.

In the CDMA radio base station described above, for example, the baseband unit 74 performs baseband signal processing on data received from the wired transmission line by the wired transmission line interface unit 75, and the radio unit 73 converts the processed baseband signal into RF signals.
The signal is converted to a signal, amplified by the transmission / reception amplifier 72, and the amplified R
The F signal is transmitted wirelessly from the sector antenna of the antenna unit 71. The transmission / reception amplification unit 72 amplifies the RF signal received by the antenna unit 71, converts the RF signal into a baseband signal by the radio unit 73, and performs the baseband signal processing on the converted baseband signal by the baseband unit 74. By transmitting the obtained data to the wired transmission path by the wired transmission path interface unit 75, signal reception processing and the like are performed. Note that the radio base station control unit 76 is provided with each of the processing units 7 described above.
Controls 1 to 75 are performed.

FIG. 6 shows a more detailed configuration example of a receiving section for each sector antenna constituted by the radio section 73 and the baseband section 74 described above. Note that, in the example of the figure, for convenience of explanation, a case is shown in which a configuration (two-sector configuration) including two sector antennas T4a and T4b is used in a CDMA radio base station. In the configuration shown in the figure, receiving sections S4a and S4b having the same configuration are provided for each of the sector antennas T4a and T4b, and the receiving section S4a provided for one of the sector antennas T4a is referred to as "".
The receiving section S4b provided in the other sector antenna T4b is shown as a "receiving section for sector B", while the receiving section S4b provided for the other sector antenna T4b is shown as a "receiving section for sector A".

Since the receiving section S4a of the sector A and the receiving section S4b of the sector B have the same configuration as described above, for the sake of convenience of explanation, these receiving sections S4a, S4
The configuration of b will be described together. That is, each receiving unit S4
a and S4b are, for example, wireless units 81a and 81b constituting the wireless unit 73 shown in FIG. 5 and a plurality of baseband cards E1a to E3a and E1b constituting the baseband unit 74 shown in FIG. E3b, a wire transmission line interface unit 97a, 97b constituting the wire transmission line interface unit 75 shown in FIG. 5, and a switching unit having a switch for selecting a signal to be combined when diversity combining is performed between sectors. 98a, 98b and a switching control unit (CONT) 99 for controlling the switching units 98a, 98b
a and 99b.

In the example of FIG. 1, three baseband cards E1a to E1a to
The figure shows a case where the baseband cards E1a to E3b and E1b to E3b are configured.
The configuration of 3b is the same. That is, each of the baseband cards E1a to E3a and E1b to E3b despreads the baseband signal input from the radio units 81a and 81b and demodulates the signal by two demodulation units 82a to 82a-8.
7a, 82b-87b, and these two demodulation units 82a-82b.
Time-division switching units 88a to 90a and 88b to 90b having switches for switching between 87a and 82b to 87b, and combining units 91a to 93 for combining demodulated signals between sectors.
a, 91b to 93b and a decoding unit 94 for performing error correction processing
a to 96a and 94b to 96b.

As described above, in the example shown in FIG. 6, each of the baseband cards E1a to E3a and E1b to E3b can process up to two received signals (that is, the number of users is two). And the total of the two receiving units S4a and S4b of sector A and sector B is 12 at the maximum.
It is possible to process received signals for the users (that is, the total number of users is 12). In addition, as described above, in the example of the figure, each of the baseband cards E1a to E3
a, E1b to E3b each have one combining unit 91
a to 93a, 91b to 93b and decoding units 94a to 96a,
94b to 96b, and the time-division switching units 88a to 90a and 88b to 90b include two demodulation units 82a to 87a and 82b to 87b and a combination unit 91a to 93b.
a, 91b to 93b, the signals from the two demodulators 82a to 87a and 82b to 87b can be processed in a time-division manner.

Next, the receiving units S4a and S4a shown in FIG.
4b shows a specific example of the operation performed by 4b. For example, the mobile station operated by the user is one of the sector antennas T4a.
If the mobile station is located in a location where communication is possible only by using the sector antenna T4
a, and is frequency-converted into a baseband signal by the radio unit 81a of the receiving unit S4a of the sector A, and then the converted baseband signal is subjected to A / D conversion by the demodulation unit 82a of a certain baseband card E1a, for example. Or despread and demodulated. Then, the demodulated signal is supplied to the combining unit 9.
1a, the signal is input to the decoding unit 94a, and the error is corrected by the decoding unit 94a.
output to a.

On the other hand, when the mobile station enters an inter-sector handover state where the mobile station can communicate with both of the two sector antennas T4a and T4b due to movement of the user, for example, the receiving sections S4a and S4b of the CDMA radio base station. Then, as described above, the plurality of sector antennas T4a, T4
b, diversity combining for combining the same signal received from the mobile station is performed. Here, such a combining process is preferably performed, for example, after demodulating a signal received by each of the sector antennas T4a and T4b.

More specifically, when the same signal wirelessly transmitted from the mobile station is received by the two sector antennas T4a and T4b, for example, the switching controllers 99a and 99b
Is a demodulation unit (any of the demodulation units 82a to 87a) for demodulating the signal in the reception unit S4a of the sector A and a demodulation unit (demodulation units 82b to 82a) for demodulating the signal in the reception unit S4b of the sector B.
87b), and a combining unit (synthesizing units 91a to 93a, 91b to 93b) to which the other specified demodulation signal output from one specified demodulation unit is connected.
Switch unit (switch unit 98).
a or 98b). As a result, the same signal specified in the combining unit to which the other demodulation unit is connected is combined, and diversity combining in the inter-sector handover state is realized.

[0014]

However, in the configuration of the receiving section of the conventional CDMA radio base station as shown in FIG. 6, for example, the above-mentioned diversity is applied to all demodulating sections provided for each sector antenna. Since the configuration is such that synthesis can be performed, there is a problem that the cost of the apparatus and the size of the apparatus are unnecessarily increased.

Specifically, for example, in the configuration shown in FIG. 6, the six demodulators 82a to 87a provided in the receiver S4a of the sector A and the six demodulators 82b provided in the receiver S4b of the sector B are provided. Although signal lines for combining are provided for all combinations so as to enable diversity combining in any of the combinations with the base stations 87b to 87b, all the mobile stations to be communicated are actually in the inter-sector handover state. Is rare, and these receiving units S4a,
Demodulation units 82a to 87a, 82b to 8 provided in S4b
All of 7b were rarely allocated to diversity combining at the same time.

As described above, the conventional CDMA radio base station receiving section has a function capable of performing diversity combining for all combinations of demodulating sections between sectors. Since such a situation hardly occurs, the load applied to the switching control units 99a and 99b shown in FIG. 6 is unnecessarily increased, and the synthesis from all demodulation units is performed. Bus lines between the sectors in order to output the signal lines for use, and the control lines for the synthesizing unit of the baseband card may be increased wastefully. However, there is a problem that the cost of the apparatus and the size of the apparatus increase. Note that such a problem is more remarkable when, for example, the number of sector antennas provided in the CDMA radio base station or the total number of users is increased.

The present invention has been made in order to solve such a conventional problem, and has a plurality of sector antennas having directivity. A signal modulated by a CDMA system and wirelessly transmitted from a mobile station is transmitted by a sector. Provided is a CDMA radio base station capable of reducing the device cost and the device size by simplifying the configuration for performing the process of synthesizing the received signal at the time of handover between sectors when receiving and demodulating by an antenna. The purpose is to do.

[0018]

To achieve the above object, a CDMA radio base station according to the present invention has a plurality of sector antennas having directivity, and is modulated by a CDMA system and transmitted by radio from a mobile station. When a signal is received by a sector antenna and the received signal is demodulated, the received signal is synthesized at the time of handover between sectors by the following configuration.

That is, in the CDMA radio base station according to the present invention, a non-handover signal processing section for demodulating a signal received by a single sector antenna and a signal processing section for demodulating a signal received by a plurality of sector antennas are provided. A handover signal processing unit capable of synthesizing signals separately provided, the control unit detects an inter-sector handover state in which the same signal wirelessly transmitted from the mobile station is received by a plurality of sector antennas, and The signal is demodulated by a handover signal processing unit to synthesize the signal.

Therefore, for example, in the conventional CDMA radio base station, when a plurality of signal processing units for demodulating a received signal are provided for each sector antenna, all of these signal processing units have been constituted by handover signal processing units. In the CDMA radio base station according to the present invention, since a part of the plurality of signal processing units is constituted by a non-handover signal processing unit, the reception signal in the inter-sector handover state is used by using the remaining handover signal processing units. In addition, it is possible to omit a signal line for combination and the like in a portion serving as a signal processing unit for non-handover while ensuring a configuration capable of combining the devices, thereby reducing the device cost and the device size. Can be.

When a signal wirelessly transmitted from a mobile station is received by a single sector antenna, demodulation processing is performed by, for example, the non-handover signal processing unit described above. Also, for example, in addition to the above-described function of performing the combining process at the time of demodulation processing in the handover signal processing unit, if a function of demodulating a signal received by a single sector antenna is provided, the signal processing for handover can be performed. It is possible to perform the same processing as that of the non-handover signal processing unit also in the unit.

Further, in the CDMA radio base station according to the present invention, the handover signal processing section is composed of a baseband unit having a demodulation section for demodulating a signal and a synthesizing section for synthesizing the signal. A plurality of signals to be combined (that is, the same signal received by a plurality of sector antennas) are demodulated and combined on the same baseband unit. When such a configuration is used, a plurality of signals to be combined can be processed on a single baseband unit, so that effects such as simplified control of the processing can be obtained.

The CDMA radio base station according to the present invention includes a plurality of sector antennas having directivity,
When a signal modulated by the MA system and wirelessly transmitted from a mobile station is received by a sector antenna, and the received signal is demodulated by a plurality of signal processing units provided for each sector antenna, inter-sector communication is performed by the following configuration. The received signal is synthesized at the time of handover.

That is, in the CDMA radio base station according to the present invention, a part of a plurality of signal processing units provided for each sector antenna may combine the signals when demodulating the signals received by the plurality of sector antennas. A non-handover signal processing unit that demodulates a signal received by a single sector antenna in place of the handover signal processing unit capable of The inter-sector handover state received by the antenna is detected, the signal is demodulated by a handover signal processing unit, and the signal is combined.

As described above, in the CDMA radio base station of the present invention, a plurality of signal processing units provided for each sector antenna are provided in accordance with, for example, the environment in which the radio base station is installed and the communication status with the mobile station. It is also possible to use a configuration in which a part of the unit can be changed from the handover signal processing unit to the non-handover signal processing unit.
It is possible to reduce the number of signal lines for combination provided in the signal processing unit.

The above-mentioned C according to claim 1 of the present invention.
The DMA radio base station is similarly created based on the idea of changing a part of the signal processing unit for handover to the signal processing unit for non-handover, but in the CDMA radio base station according to claim 1, It is not necessary to use a configuration in which the signal processing unit for handover and the signal processing unit for non-handover can be changed, and the number of signal processing units for handover and the number of non-handover signal processing units are fixed. Configurations may be used.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS CDM according to a first embodiment of the present invention
The wireless base station A will be described with reference to the drawings. FIG. 1 shows an example of a CDMA radio base station according to the present invention. The CDMA radio base station includes an antenna unit 1 provided with a plurality of sector antennas for transmitting and receiving RF signals, and an RF signal to be transmitted. And a transmission / reception amplifier (AMP) 2 for amplifying a received RF signal and a radio (RF) unit (TRX) 3 for converting a baseband signal to an RF signal and for converting an RF signal to a baseband signal. A baseband (BB) unit 4 for performing baseband signal processing, a wired transmission line interface unit (HWY INT) 5 for converting data between the baseband unit 4 and the wired transmission line, and an MCC-SIM, for example. And a radio base station control unit (CNT) 6 for transmitting and receiving a control signal to and from the radio base station and managing the radio channel.

Here, the plurality of sector antennas provided in the above-mentioned antenna unit 1 are directional antennas, and the CDMA radio base station of this embodiment uses the sector antenna to perform CDMA communication with a mobile station. The signal is wirelessly communicated by the method. Specifically, in the CDMA radio base station of this example, for example, a signal modulated by the CDMA system is wirelessly transmitted to the mobile station by the sector antenna, while a signal modulated by the CDMA system and wirelessly transmitted from the mobile station. Is received by the sector antenna, and the received signal is demodulated.

In this example, the baseband unit 4 includes a handover component used for handover (HO) between sectors and a non-handover component used when such handover is not performed. As will be described later, the CDMA radio base station of the present embodiment has a handover for handover when an inter-sector handover state occurs with a mobile station to be communicated (at the time of inter-sector handover). While the components perform the processing of the received signal, if the inter-sector handover state does not occur (at the time of non-handover), the control is performed so that the non-handover component processes the received signal.

As described above, the transmission processing and the reception processing of the RF signal performed by the CDMA radio base station of the present embodiment are selectively performed by the handover signal processing unit and the non-handover signal processing unit in the present embodiment. Except that the receiving process is performed by using the CDMA system shown in FIG.
Since the processing is almost the same as the communication processing performed by the radio base station, the description of the same processing as that of the CDMA radio base station shown in FIG. 5 will be omitted in this example.

FIG. 2 shows a more detailed configuration example of the receiving section for each sector antenna, which is composed of the radio section 3 and the baseband section 4 provided in the above-described CDMA radio base station of the present embodiment. . In this example, for convenience of explanation,
The CDMA radio base station has two sector antennas T1a, T1
1 shows a case where a configuration having 1b (two-sector configuration) is used. In the configuration shown in the figure, receiving sections S1a, S1a having the same configuration for each of the sector antennas T1a, T1b,
S1b, and one sector antenna T1a
The receiving unit S1a provided for the other sector antenna T1b is shown as a "receiving unit for the sector B" while the receiving unit S1a provided for the other is shown as a "receiving unit for the sector A".

Here, as described above, since the receiving section S1a of the sector A and the receiving section S1b of the sector B have the same configuration, for convenience of explanation, these receiving sections S1a, S1 are used.
The configuration of b will be described together. That is, each receiving unit S1
a and S1b are, for example, wireless units 11a and 11b constituting the wireless unit 3 shown in FIG. 1 and a plurality of baseband cards B1 constituting the baseband unit 4 shown in FIG.
a to B3a and B1b to B3b, and the wire transmission line interface units 25a and 25b constituting the wire transmission line interface unit 5 shown in FIG. 1 described above, and select a signal to be synthesized when diversity combining is performed between sectors. Switching units 26a and 26b having switches;
a, a switching control section (CONT) 27a for controlling 26b,
27b.

In this example, the baseband section for each sector is divided into three baseband cards B1a to B3a, B3B.
1B to B3b, three baseband cards B1a to B3 provided for each sector.
a, two baseband cards B among B1b to B3b
1a to B2a and B1b to B2b are configured for non-handover, and the remaining one baseband card B3
a and B3b are configured for handover. In addition,
The configuration of two non-handover baseband cards (baseband card B1a and baseband card B2a, and baseband card B1b and baseband card B2b) provided for each sector is the same as each other.

Baseband card B for non-handover
1a to B2a and B1b to B2b respectively
Two demodulation units 12a to 15a for despreading the baseband signals input from 1a and 11b and demodulating the signals;
12b to 15b and these two demodulation units 12a to 15b
a, time-division switching units 18a to 19a and 18b to 19b each having a switch for switching between a and 12b to 15b, and decoding units 21a to 22a and 21b to 22b for performing error correction processing. In this example, the above-described non-handover baseband cards B1a to B2a, B1b to B2
b constitutes a non-handover signal processor for demodulating a signal received by a single sector antenna.

The handover baseband cards B3a and B3b are respectively provided with the non-handover baseband cards B1a to B2a and B1b to B3.
2b, two demodulation units 16a-1
7a, 16b to 17b and time-division switching units 20a, 20b
And decoding sections 23a and 23b, and combining sections 24a and 24b for combining demodulated signals between sectors.
Is provided.

In this example, two demodulators 16a, 17a provided in the handover baseband card B3a in sector A and two demodulators 16b, 17 provided in the handover baseband card B3b in sector B are used.
b, the output ends of the demodulators 16a to 17a and 16b to 17b of each of these sectors (sector A and sector B) and the other sector (sector B and sector A) so that the demodulated signals can be combined for all the combinations. ) Are provided with signal lines (signal lines for combination) for connecting to the input terminals of the combining units 24b and 24a. As described above, the switching between the demodulation units 16a to 17a and 16b to 17b of one sector and the combining units 24b and 24a of the other sector is performed by the switching units 26a and 26b. This is performed under the control of 27a and 27b.

In this embodiment, a handover signal processing section capable of synthesizing signals received by a plurality of sector antennas by the handover baseband cards B3a and B3b when demodulating the signals is configured. The signal processing unit for handover is provided separately from the signal processing unit for non-handover described above. The handover baseband card B of this example
In 3a and B3b, for example, the switching units 26a and 26b turn off the connection of the demodulated signals input from the other sector to the combining units 24a and 24b, so that the non-handover baseband cards B1a to B2a and B1b to B2b.
, Ie, demodulation of a signal received by a single sector antenna.

In this embodiment, for example, the same signal wirelessly transmitted from a mobile station is transmitted to a plurality of sector antennas T1a and T1a.
1b, the switching control unit 27 described above.
a and 27b control the switching units 26a and 26b to cause the handover baseband cards B3a and B3b to perform diversity combining between sectors, so that the same signal wirelessly transmitted from the mobile station is transmitted by a plurality of sector antennas. Control means is configured to detect a received inter-sector handover state, demodulate the signal by a handover signal processor, and combine the signals.

In this example, as described above, each of the baseband cards B1a to B3a and B1b to B3b has a configuration capable of processing a maximum of two received signals (that is, the number of users is two). And the two receiving units S1a and S1b of the sector B as a whole can process received signals of up to 12 users (that is, the total number of users is 12).

As described above, in each of the baseband cards B1a to B3a and B1b to B3b of the present embodiment, one decoding unit 21a to 23a and 21b to 23b are provided for two demodulation units 12a to 17a and 12b to 17b. (In the case of the handover baseband cards B3a and B3b, the synthesizing units 24a and 24b are also shared), and the time-division switching units 18a to 20a and 18b to 20b are connected to the two demodulation units 12a to 17a and 12b. By switching the connection with the decoding units 21a to 23b, the decoding units 21a to 23a, 21b to 23b, etc. process the signals from the two demodulation units 12a to 17a and 12b to 17b in a time-division manner.

Next, the receiving section S1 of the present embodiment shown in FIG.
a, a specific example of the operation performed in S1b will be described. For example, when a mobile station operated by a user is located in a place where communication is possible with only one sector antenna T1a (sector A), a signal wirelessly transmitted from the mobile station is received by the sector antenna T1a. After being frequency-converted into a baseband signal by the radio unit 11a of the receiving unit S1a of the sector A, the converted baseband signal is subjected to A / D conversion or despreading by the demodulation unit 12a of the non-handover baseband card B1a, for example. Demodulated. Then, the demodulated signal is input to the decoding unit 21a and error-corrected, and then output to the wired transmission line interface unit 25a.

On the other hand, for example, when the mobile station enters an inter-sector handover state where the mobile station can communicate with both of the two sector antennas T1a and T1b due to the movement of the user or the like, the receiving sections S1a and S1b of the CDMA radio base station. Then, a baseband card for processing a signal received from the mobile station is changed to a handover baseband card B3a,
B3b and a plurality of sector antennas T1a,
1b, a diversity combining process for combining the same signal received from the mobile station.

More specifically, when the same signal wirelessly transmitted from the mobile station is received by the two sector antennas T1a and T1b, in the CDMA radio base station, for example, the switching control units 27a and 27b perform this operation. Handover state between sectors is detected. Here, any detection method may be used. For example, a signal demodulated with the same spreading code is detected by the receiving unit S1a of the sector A and the receiving unit S1b of the sector B. Accordingly, a mode in which these signals are regarded as the same signal can be used. Also, for example, in order to distinguish between a signal from a mobile station and noise, a level (threshold) at which a signal from the mobile station is considered to be received is provided, and a signal having a level lower than the threshold is regarded as noise. It can also be used.

When the inter-sector handover state is detected as described above, the same signals received from the mobile station by the sector antennas T1a and T2a are respectively transmitted to the handover baseband cards B3a and B3b of each sector.
Control is performed so that demodulation is performed by the demodulation units 16a to 17a and 16b to 17b. Also, for example, the switching control unit 27
In a and 27b, a demodulation unit (either demodulation unit 16a or 17a) that demodulates the signal in the reception unit S1a of the sector A and a demodulation unit (the same signal) that demodulates the signal (the same signal) in the reception unit S1b of the sector B A demodulation unit 16b or 17b), and a combining unit (combining unit 2) to which the other demodulation unit that has specified the demodulated signal output from one of the identified demodulation units is connected.
4a and 24b) to control the switching of the switch of the switching unit (any of the switching units 26a and 26b).

As a result, the specified same signal is synthesized in the synthesizing unit to which the other demodulation unit is connected, and diversity combining in the inter-sector handover state is realized. The combined signal is supplied to a decoding unit (decoding unit 23).
a, 23b), and is decoded by the wired transmission path interface section (the wired transmission path interface section 25a,
25b).

The plurality of sector antennas T1a, T1
b) a demodulator used for demodulating the same signal received from the mobile station by the baseband card B for handover.
Demodulators 16a to 17a and 16b to 17 on 3a and B3b
The process of switching to b is performed, for example, by changing a spreading code (code) used for despreading in a demodulation unit that attempts to demodulate the signal to a code corresponding to the signal, or by demodulating with such a change. This is realized by changing the address for recognizing the unit (that is, the correspondence of which demodulation unit uses which spreading code).

By performing the above processing, in the CDMA radio base station of this embodiment, for example, when the mobile station is under the control of one sector antenna T1a (sector A), the non-handover baseband of the sector A Card B
1a and B2a, the mobile station is moving under the other sector antenna T1b (sector B) and the inter-sector handover is under the control of both sector antennas T1a and T1b. Baseband card B3 for handover of sector A and sector B
a, B3b to perform diversity combining of the signals, and demodulate the signals using the non-handover baseband cards B1b and B2b in the sector B when the handover process is completed, for example. Perform switching.

As described above, for example, in the conventional CDMA radio base station, all of the plurality of signal processing units provided for each sector are configured as handover signal processing units as shown in FIG. Therefore, in the CDMA radio base station of this example, for example, when providing the same number of signal processing units,
A part of the plurality of signal processing units is configured as a handover signal processing unit, and the other is configured as a non-handover signal processing unit. Therefore, the configuration of such a signal processing unit can be simplified. .

More specifically, in the CDMA radio base station of this example, the switching control unit 27 is provided, for example, by providing a non-handover signal processing unit instead of the handover signal processing unit.
a, 27b, the number of components of the combining unit provided in the signal processing unit, the number of combining signal lines (that is, bus lines between sectors), and the number of control lines for the combining unit are reduced. Accordingly, it is possible to reduce the cost of the device and the size of the device.

In the CDMA radio base station of the present embodiment, for example, at least one of the plurality of signal processing units is configured as a handover signal processing unit, so that the handover signal processing unit is used. As a result, a configuration capable of combining received signals in the inter-sector handover state is ensured.

Here, for example, the ratio of the number of signal processing units provided for each sector antenna to the number of signal processing units for handover and the number of non-handover signal processing units depends on the ratio between the CDMA radio base station and the plurality of signal processing units. Corresponds to the maximum number of mobile stations (users) that are expected to overlap at the same time in the inter-sector handover process (diversity combining process between sectors) in the actual communication situation performed with the mobile station. It is preferable to set the ratio to such an extent that the number of handover signal processors can be set to a necessary and sufficient level.

Next, the CDMA according to the second embodiment of the present invention will be described.
The radio base station will be described with reference to FIG. In this example, C
Since the overall configuration of the DMA radio base station is, for example, the same as that shown in FIG. 1 of the first embodiment, description of the overall configuration will be omitted in this example.
A configuration of a receiving unit according to a main part of the CDMA radio base station of the present example will be described. Note that, for convenience of explanation, the same reference numerals as those of the processing units 1 to 6 shown in FIG.

FIG. 3 shows a more detailed configuration example of the receiving section for each sector antenna, which is composed of the radio section 3 and the baseband section 4 provided in the CDMA radio base station of the present embodiment. . Note that, in this example, as in the case of the first embodiment, a case is shown in which a configuration (two-sector configuration) including two sector antennas T2a and T2b is used in a CDMA radio base station. In the configuration shown in the figure, receiving sections S2a and S2b having the same configuration are provided for each of the sector antennas T2a and T2b, and the receiving section S2a provided for one of the sector antennas T2a is set to receive the sector A. The receiving unit S2b provided in the other sector antenna T2b is shown as a "receiving unit for sector B".

Here, as described above, the receiving section S2a of the sector A and the receiving section S2b of the sector B have the same configuration, and for convenience of explanation, these receiving sections S2a, S2
The configuration of b will be described together. That is, each receiving unit S2
a and S2b are, for example, wireless units 31a and 31b and two non-handover baseband cards C1a to C2a and C1b to C similar to those shown in FIG. 2 of the first embodiment.
2b and a wired transmission line interface unit 45a, 45b, and a switch for selecting a signal to be combined when performing diversity combining between one handover baseband card C3a, C3b and a sector. The first switching units 46a and 46b and the first switching unit 46
a, 46b and switching control units (CONT) 47a, 47b for controlling second switching units 40a, 40b described later.

As described above, in this embodiment, as in the case of the first embodiment, the baseband section for each sector is set to 3
Baseband cards C1a to C3a, C1b to C3
b, and two baseband cards C1a-C2a and C1b-C2b among three baseband cards C1a-C3a and C1b-C3b provided for each sector.
Are configured for non-handover, and the combining units 44a, 4b are added to the remaining one baseband card C3a, C3b.
4b, etc., for handover.

Baseband card C for non-handover
The configurations of 1a to C2a and C1b to C2b are the same as the configurations of the non-handover baseband cards B1a to B2a and B1b to B2b shown in FIG. 2 of the first embodiment, for example. Band card C1
a to C2a and C1b to C2b respectively have two demodulators 32a to 35a and 32a similar to those in the first embodiment.
b to 35b and time division switching units 38a to 39a, 38b
To 39b, and decoding units 41a to 42a and 41b to 42b. In this example, the above-described non-handover baseband cards C1a to C2a, C1b to C2
b constitutes a non-handover signal processor for demodulating a signal received by a single sector antenna.

The handover baseband cards C3a and C3b are respectively provided with the non-handover baseband cards C1a to C2a and C1b to C3.
2b, two demodulators 36a-3a similar to those provided in
7a, 36b-37b and decoding sections 43a, 43b, and combining sections 44a, 44b for combining demodulated signals between sectors, and two demodulating sections 36a-37a, 36b-37b. Output terminal and synthesis unit 44
The second switching units 40a and 40b are provided for switching the connection between the input terminals a and 44b.

Here, in the configuration of the first embodiment, the signals received by one sector antenna T1a, T1b are demodulated by the handover baseband cards B3a, B3b provided in the sector and then connected to the other sector. However, in the configuration of this example, for example, the radio units 31 provided in the receiving units S2a and S2b of the sectors A and B, respectively.
Before demodulation of the signals output from a and 31b, to the demodulators 36b to 37b and 36a to 37a on the handover baseband cards C3b and C3a provided in the receivers S2b and S2a of the other sectors B and A, respectively. A configuration to be connected is used.

More specifically, the first switching units 46a and 46b of each of the sectors A and B include the radio units 31 of the sectors A and B.
a, the signal output from 31b or the other sector B,
One of the signals output from the wireless units 31b and 31a of A is transferred to the handover baseband cards C3a and C3b.
Demodulators 36a to 37a, 36b to 37 provided above
It has a function of switching to input to the input terminal of b.
In the second switching units 44a and 44b of the sectors A and B, the two demodulation units 36a to 3b on the handover baseband cards C3a and C3b provided in the sectors A and B, respectively.
It has a function of switching both or one of the demodulated signals output from 7a and 36b to 37b to the combining units 44a and 44b.

With this configuration, in this example, the switching control units 47a and 47b provided in the sectors A and B
By controlling the switching of the switching units 46a and 46b and the switches of the second switching units 40a and 40b, the signal received by one sector antenna T2a and the signal received by the other sector antenna T2b are converted into the same handover base. Diversity combining is performed after demodulation on band cards C3a and C3b. Note that the receiving unit S of this example
2a, the operation performed by S2b, that is, mainly
Non-handover baseband cards C1a to C2a and C1b to be used for signal processing according to the communication status with the mobile station
C2b and handover baseband cards C3a, C
The operation of switching between 3b and 3b is the same as, for example, the case of the first embodiment, and thus the description is omitted.

In this example, a handover signal processing section capable of combining signals received by a plurality of sector antennas when demodulating the signals received by the plurality of sector antennas by the handover baseband cards C3a and C3b is configured. Have been. In this example, for example, the same signal wirelessly transmitted from a mobile station is transmitted to a plurality of sector antennas T2a,
When received by T2b (at the time of inter-sector handover), the above-mentioned switching control units 47a and 47b control the first switching units 46a and 46b and the second switching units 40a and 40b to transmit the handover baseband cards C3a and C3b. By performing diversity combining between sectors, the same signal wirelessly transmitted from the mobile station is detected by a plurality of sector antennas, an inter-sector handover state is detected, and the signal is demodulated by a handover signal processing unit. Thus, a control means for synthesizing the signals is configured.

As described above, in the CDMA radio base station of this embodiment, as in the case of the first embodiment, some of the plurality of signal processing units are configured as handover signal processing units, and the rest are non-handover. Since the signal processing unit is configured as a handover signal processing unit, the configuration of the signal processing unit can be simplified, thereby reducing the device cost and the device size.

In the CDMA radio base station of this embodiment, one sector antenna T
When diversity combining is performed between the signal received at 2a and T2b and the same signal (same signal received from the same mobile station) received at the other sector antennas T2b and T2a, both signals to be combined are demodulated. Previously, it is connected to one handover baseband card C3a, C3b provided in any one of the sectors A and B, and both signals are connected to this one handover baseband card C3.
a, demodulation by despreading and the like on C3b, synthesis, and decoding, so that the bus line configuration and the like are further simplified as compared with the configuration of the first embodiment shown in FIG. And control in the baseband unit can be simplified.

As described above, in the CDMA radio base station according to the present embodiment, the handover signal processing section is constituted by the baseband unit having the demodulation section for demodulating the signal and the synthesizing section for synthesizing the signal. By demodulating and combining a plurality of signals (the same signal received from the mobile station) on the same baseband unit, it is possible to further reduce the device cost and the device size. In this example, a baseband card is used as the baseband unit, but the baseband unit may have any shape or the like.

Next, the CDMA according to the third embodiment of the present invention will be described.
The radio base station will be described with reference to FIG. In this example, C
Since the overall configuration of the DMA radio base station is, for example, the same as that shown in FIG. 1 of the first embodiment, description of the overall configuration will be omitted in this example.
A configuration of a receiving unit according to a main part of the CDMA radio base station of the present example will be described. Note that, for convenience of explanation, the same reference numerals as those of the processing units 1 to 6 shown in FIG.

FIG. 4 shows a more detailed configuration example of the receiving section for each sector antenna, which is composed of the radio section 3 and the baseband section 4 provided in the CDMA radio base station of the present embodiment. . In this example, as in the case of the first embodiment, a case is shown in which a configuration including two sector antennas T3a and T3b in a CDMA radio base station (two-sector configuration) is used. In the configuration shown in the figure, receiving sections S3a and S3b having the same configuration are provided for each of the sector antennas T3a and T3b, and the receiving section S3a provided for one of the sector antennas T3a is referred to as "Sector A reception". The receiving section S3b provided in the other sector antenna T3b is shown as a "receiving section for sector B".

Here, since the receiving section S3a of the sector A and the receiving section S3b of the sector B have the same configuration as described above, for convenience of explanation, these receiving sections S3a, S3
The configuration of b will be described together. That is, each receiving unit S3
a and S3b are, for example, wireless units 52a and 51b and two non-handover baseband cards D1a to D2a and D1b to D similar to those shown in FIG. 2 of the first embodiment.
2b and wired transmission line interface units 65a, 65b. One handover baseband card D3a, D3b and switching units 60a, 60
b, switching control units (CONT) 66a and 66b for controlling b.

As described above, in the present embodiment, as in the case of the first embodiment, the baseband section for each sector is set to 3
Baseband cards D1a to D3a, D1b to D3
b, and two baseband cards D1a-D2a and D1b-D2b of three baseband cards D1a-D3a and D1b-D3b provided for each sector.
For the non-handover, and the combining units 64a, 64b are added to the remaining one baseband card D3a, D3b.
4b, etc., for handover.

Baseband card D for non-handover
The configurations of 1a to D2a and D1b to D2b are the same as the configurations of the non-handover baseband cards B1a to B2a and B1b to B2b shown in FIG. 2 of the first embodiment, for example. Band card D1
a to D2a and D1b to D2b respectively have two demodulators 52a to 55a and 52a similar to those in the first embodiment.
b to 55b and time division switching units 58a to 59a, 58b
59b and decoding sections 61a to 62a and 61b to 62b. In this example, the above-described non-handover baseband cards D1a to D2a, D1b to D2
b constitutes a non-handover signal processor for demodulating a signal received by a single sector antenna.

Each of the handover baseband cards D3a and D3b of the present embodiment has the above-described non-handover baseband cards D1a to D2a, for example, similarly to the configuration shown in FIG. 3 of the second embodiment. , D1b-D2
b, two demodulators 56a-57 similar to those provided in
a, 56b to 57b and decoding sections 63a and 63b, and synthesizing sections 64a and 64b for synthesizing demodulated signals between sectors, and the two demodulating sections 5 described above.
Output terminals of 6a-57a, 56b-57b and combining section 64
Switching units 60a and 60b each having a switch for selecting a signal to be combined when diversity combining is performed between sectors by switching connections between the input terminals a and 64b are provided.

Here, in the configuration of the second embodiment, the demodulators 36a-37a, 36 on the handover baseband cards D3a, D3b provided in the sectors A, B, respectively.
Although the first switching units 46a and 46b are provided at the preceding stage of b to 37b to switch the signals to be input to the demodulation units 36a to 37a and 36b to 37b, the configuration of the present example uses , B, one demodulation section 56a on the handover baseband card D3a, D3b,
An input end of 56b is a radio section 51a of the sector A or B,
The output terminal of the other demodulator 5b is connected to the output end of the other demodulator 5b.
A configuration is used in which the output terminals of the radio units 51b and 51a of the other sectors B and A are connected to the input terminals of 7a and 57b.

That is, in this embodiment, the switches corresponding to the first switching units 46a and 46b shown in the second embodiment are not provided, and the handover baseband card D3a provided in each of the sectors A and B is not provided. , D3b, one of the demodulation units 56a to 57a, 56b to 57b always receives the reception signals output from the radio units 51a, 51b of the sectors A and B, and the other always receives the other sector B , A are provided with wires for receiving the received signals output from the wireless units 51b and 51a.

With this configuration, in this example, the switching control units 66a and 66b provided in each of the sectors A and B perform switching control of the switches of the switching units 60a and 60b. The demodulated signal and the same signal received by the other sector antenna T3b (the same signal received from the same mobile station) are subjected to diversity combining after demodulation on the same handover baseband cards D3a and D3b. Will be The operations performed by the receiving units S3a and S3b of this example, that is, the non-handover baseband cards D1a to D2 mainly used for signal processing according to the communication status with the mobile station
The operation for switching between a and D1b to D2b and the handover baseband cards D3a and D3b is the same as, for example, the case of the first embodiment, and a description thereof will be omitted.

In this example, a handover signal processing unit capable of combining signals received by a plurality of sector antennas when demodulating the signals received by the plurality of sector antennas by the handover baseband cards D3a and D3b is configured. Have been. In this example, for example, the same signal wirelessly transmitted from the mobile station is transmitted to a plurality of sector antennas T3a,
When receiving by T3b (at the time of handover between sectors), the switching control units 66a and 66b
a, 60b to control the handover baseband cards D3a, D3b to perform diversity combining between sectors, so that the same signal wirelessly transmitted from the mobile station is received by a plurality of sector antennas. Control means for detecting a state, demodulating the signal by a handover signal processor, and synthesizing the signal is configured.

As described above, in the CDMA radio base station according to the present embodiment, as in the case of the first embodiment, a part of the plurality of signal processing units is configured as a handover signal processing unit, and the rest is not. Since the signal processing unit is configured as a handover signal processing unit, the configuration of the signal processing unit can be simplified, thereby reducing the device cost and the device size.

Also, in the CDMA radio base station of this embodiment, as in the case of the second embodiment, a plurality of signals to be combined (the same signal received from the mobile station) are transmitted on the same baseband card. Since the configuration is such that demodulation, synthesis, and decoding are performed, it is possible to further reduce the device cost and the device size. In the CDMA radio base station according to the present embodiment, the first switching units 46a and 46b shown in the second embodiment are used.
By omitting the switch corresponding to, the configuration for performing diversity combining is further simplified.

In the above embodiment, the number of handover signal processors and the number of non-handover signal processors provided for each sector antenna of the CDMA radio base station are fixed. Although a configuration example has been shown, in the CDMA radio base station of the present invention, for example, a part of a plurality of signal processing units provided for each sector antenna may be replaced with a handover signal processing unit as a non-handover signal processing unit. A possible configuration is also possible, which allows
It is also possible to adopt a configuration in which the ratio between the signal processing unit for handover and the signal processing unit for non-handover can be changed according to the usage status of the wireless base station.

Specifically, for example, by preparing a baseband card capable of switching between a handover type and a non-handover type (including a mode in which the baseband card itself can be removed and replaced at appropriate times). It is possible to change the ratio between the baseband card for handover and the baseband card for non-handover used for processing the received signal at the radio base station according to the traffic situation at the place where the CDMA radio base station is installed. Possible configurations are also possible. When such a configuration is used, for example, without changing the total number of baseband cards provided in the CDMA radio base station,
By changing the ratio between the number for handover and the number for non-handover, it is possible to flexibly cope with traffic conditions.

In the CDMA radio base station according to the present invention,
For example, the number of sector antennas (that is, sectors) provided in the radio base station and the total number of signal processing units provided for each sector antenna (in the above embodiment, the number of signal processing units for handover and non-handover Total)
Various modes are used as the ratio of the number of handover signal processing units to the number of non-handover signal processing units, the maximum number of signals that can be demodulated simultaneously (the number of users), and the like. Is also good. Note that, for example, as the number of sectors, the number of signal processing units, and the number of users increase, the effect obtained by the present invention increases.

The configuration of the signal processing unit for handover and the signal processing unit for non-handover is not necessarily limited to that shown in the above embodiment, and various configurations may be used. As an example, in the above-described embodiment, the configuration after the baseband unit (on the side of the wired transmission line interface unit) is divided for each sector, and a signal processing unit for handover is provided in a separate unit for each sector.
For example, a mode in which the handover signal processing units provided for a plurality of sectors are integrated into one unit may be used.

In the above-described embodiment, the CDMA radio base station is provided with two sector antennas, and the two signals (the same signal) received by these sector antennas are combined. In the configuration in which the sector antennas are provided, the number of signals to be combined at the time of inter-sector handover, that is, the number of the same signals received from the sector antennas may be arbitrarily determined. Specifically, for example, in the configuration as in the first embodiment or the second embodiment, switching is performed so that the same signal received by three or more sector antennas (or all of them) may be combined. For example, in the configuration of the third embodiment, the output terminal of each wireless unit provided in three or more sector antennas (or all of them) may be connected to one handover base. A wiring configuration that connects to each demodulation unit (for example, a different demodulation unit for each sector) on the band card may be used.

Further, as a configuration for controlling the demodulation processing of a received signal by selectively using the handover signal processing unit and the non-handover signal processing unit provided in the CDMA radio base station, for example, a hardware having a processor, a memory, etc. The processor may be realized by executing a control program in the wear resource, and each functional means for executing, for example, a demodulation process performed by the CDMA radio base station is configured as an independent hardware circuit. Is also good.

[0083]

As described above, the CD according to the present invention is
According to the MA radio base station, in a configuration in which a plurality of sector antennas having directivity are provided, a signal modulated by the CDMA system and wirelessly transmitted from the mobile station is received by the sector antenna, and the received signal is demodulated, A signal processing unit for handover and a signal processing unit for handover are separately provided, and the same signal wirelessly transmitted from the mobile station is demodulated by the handover signal processing unit during inter-sector handover in which the same signal is received by a plurality of sector antennas. Since the signals are processed and combined, for example, at the time of inter-sector handover, a configuration capable of performing diversity combining of received signals is ensured, and a signal line for combining is provided for the non-handover signal processing unit. Since there is no need, the cost of equipment and the size of equipment can be reduced. .

In the CDMA radio base station according to the present invention, a plurality of signals to be combined are demodulated and combined on the same baseband unit at the time of the combining, so that processing for the combining is performed. Control can be simplified. In the CDMA radio base station according to the present invention, for example, a configuration may be used in which a part of a plurality of signal processing units provided for each sector antenna is replaced with a non-handover signal processing unit instead of a handover signal processing unit. For example, a configuration in which the ratio between the handover signal processing unit and the non-handover signal processing unit can be changed according to the communication status of the CDMA radio base station or the like can be used.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a CDMA radio base station according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration example of a main part of a CDMA radio base station according to a first embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration example of a main part of a CDMA radio base station according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration example of a main part of a CDMA radio base station according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a CDMA radio base station according to a conventional example.

FIG. 6 is a diagram illustrating a configuration of a receiving unit of a CDMA radio base station according to a conventional example.

[Explanation of symbols]

1. Antenna section, 2. Transmission / reception amplification section, 3. Radio section, 4. Baseband section, 5. Wire transmission path interface section, 6. Radio base station control section, T1a-T
3a, T1b to T3b ··· Sector antenna, S1a to S
3a, S1b to S3b ... receiving units, 11a, 11b, 3
1a, 31b, 51a, 51b ... wireless section, B1a, B
2a, B1b, B2b, C1a, C2a, C1b, C2
b, D1a, D2a, D1b, D2b: baseband card for non-handover, B3a, B3b, C3a, C
3b, D3a, D3b... Baseband card for handover, 12a to 17a, 12b to 17b, 32a to 3
7a, 32b to 37b, 52a to 57a, 52b to 57
b demodulation unit, 18a to 20a, 18b to 20b, 38
a, 39a, 38b, 39b, 58a, 59a, 58
b, 59b... switching unit for time division, 21a to 23a, 21
b to 23b, 41a to 43a, 41b to 43b, 61a
To 63a, 61b to 63b... Decoding part, 24a, 24
b, 44a, 44b, 64a, 64b...
a, 25b, 45a, 45b, 65a, 65b ··· Wired transmission line interface section, 26a, 26b, 40a,
40b, 46a, 46b, 60a, 60b switching unit,
27a, 27b, 47a, 47b, 66a, 66b ...
Switching control unit,

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shunji Abe 3-14-20 Higashinakano, Nakano-ku, Tokyo Kokusai Denki Co., Ltd. F term (reference) 5K059 CC03 CC04 DD33 DD37 EE03 5K067 AA03 AA34 BB02 CC10 CC24 DD13 DD17 DD51 EE10 EE24 GG01 GG11 HH24 JJ36 JJ39 KK02 KK03

Claims (3)

[Claims] 1. A CDMA radio base station comprising a plurality of sector antennas having directivity, receiving a signal modulated by a CDMA system and wirelessly transmitted from a mobile station by a sector antenna, and demodulating the received signal. A non-handover signal processing unit for demodulating a signal received by a single sector antenna, and a handover signal processing unit for combining the signals when demodulating a signal received by a plurality of sector antennas; The same signal wirelessly transmitted from the mobile station is received by a plurality of sector antennas, the inter-sector handover state is detected, and the signal is demodulated by a handover signal processing unit to synthesize the signal. A CDMA radio base station comprising control means. 2. The CDMA radio base station according to claim 1, wherein the handover signal processing unit comprises a baseband unit having a demodulation unit for demodulating a signal and a synthesizing unit for synthesizing the signal. A CDMA radio base station characterized in that a plurality of signals to be combined are demodulated and combined on the same baseband unit. 3. A signal provided with a plurality of sector antennas having directivity, receiving a signal modulated by a CDMA system and wirelessly transmitted from a mobile station by a sector antenna, and a plurality of received signals provided for each sector antenna. In a CDMA radio base station that performs demodulation processing by a processing unit, it is possible to combine a part of a plurality of signal processing units provided for each sector antenna when demodulating a signal received by a plurality of sector antennas. A non-handover signal processing unit that demodulates a signal received by a single sector antenna in place of a simple handover signal processing unit, and the same signal wirelessly transmitted from a mobile station is received by a plurality of sector antennas The inter-sector handover state is detected, the signal is demodulated by the handover signal processing unit, and the CDMA wireless base station, characterized in that it comprises a control means for synthesizing.