JP2000286779A - Base station device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously realize call channel and control channel transmission in an omnibearng mobile station by transmitting a call channel in an adaptive array antenna formed of plural first antennas with a directional pattern adapted to a mobile station position or a control channel with a second antenna which is separately installed in a base station. SOLUTION: When a transmission period instruction signal is on and a control channel instruction signal is off, a call channel appears in a base band signal and the call channel is transmitted/received by an adaptive array containing the four transmission/reception systems of antennas 17-20. In a period when the control channel instruction signal is on, transmission circuits 5, 7 and 9 become a stop state and a switch 26 is changed over from a contact point B to A. Thus, a radio wave is transmitted by using only the combination of a transmission circuit 3 and an antenna 21. The antenna 21 has an antenna gain 16 dBi and the control channel can be transmitted with the same gain as the adaptive array.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station apparatus having an adaptive array for forming a directivity pattern adaptively by a plurality of antennas.

[0002]

2. Description of the Related Art Current personal handy phone system
(PHS), the transmission power between the mobile station and the base station is up to 10mW
And 500mW. In such a system in which the transmission output ratio between the mobile station and the base station is large, it is desirable that the base station transmits and receives radio waves using a diversity system or an adaptive array system.

In the former diversity system, a base station is provided with a plurality of antennas, and when transmitting and receiving radio waves to and from a mobile station on the other end, the antenna with the best radio wave condition is specified from the plurality of antennas. By transmitting and receiving radio waves using the specified antenna, transmission and reception with the mobile station can be performed well. On the other hand, the latter adaptive array system is a system in which a desired directivity pattern is formed using a plurality of sets of a transmitting circuit, a receiving circuit, and an antenna. Here, when a user is present in a predetermined direction when viewed from the adaptive array type base station apparatus, the base station apparatus changes the amplitude and phase in a combination of the transmission circuit and the antenna to change the specific amplitude and phase. A directional pattern having directivity only in the azimuth is formed. Then, the base station device can make the radio wave reach only the specific user.

When an interference wave is generated in a predetermined direction when viewed from the base station apparatus, the base station apparatus forms a directivity pattern having no directivity in this direction. This allows
The base station apparatus can efficiently perform the countermeasure against the interference wave, and the user can talk in a favorable radio wave condition. Details of the adaptive array method are described in “Special Issue on Adaptive Signal Processing in the Spatial Domain and its Application Technology” (Transactions of the Institute of Electronics, Information and Communication Engineers, VOL.J75-B-II.11 NOVEMBER). Is omitted.

[0005]

By the way, when an adaptive array type base station apparatus is introduced into PHS,
The adaptive array base station is suitable for transmitting a communication channel specified by PHS, but is not suitable for transmitting a control channel. Here, the communication channel is a channel for transmitting communication data in the PHS (called a TCH in the PHS), and the PHS.
Are transmitted and received using one time slot for each of the uplink and downlink in the TDMA frame specified in. Since this speech channel needs to be transmitted only in the direction in which the mobile station with which the line connection with the base station has been established exists, the adaptive array type base station forms a directivity pattern such that directivity appears in that direction. I just need.

On the other hand, the control channel is a channel used for transmitting and receiving control signals such as location registration and outgoing / incoming calls.
(In PHS, it is called CCH.) It is composed of a plurality of time slots transmitted and received intermittently. This control channel must be transmitted not only to mobile stations for which a line connection has been established, but also to mobile stations in a standby state. The reason for this is that the control channel is a mobile station in a standby state, such as information for acquiring synchronization, a broadcast channel for broadcasting the structure of a communication channel, and a paging channel for calling a nearby mobile station. Contains information to be received. For this reason, if the directivity pattern in which the directivity appears only in the direction in which the mobile station for which the line connection has been established exists as described above, the mobile station in the standby state cannot receive the control channel at all.

However, in the adaptive array system,
Since it is possible to form all directional patterns by controlling the amplitude and phase, a directional pattern is formed so that the directional pattern appears in one direction, and after transmitting the control channel, the directional pattern appears in another direction. Thus, the control channel can be transmitted by forming a directivity pattern. By repeating this process, it is possible to cover all directions in which the mobile station in the standby state may exist. However, in this method, since it is necessary to repeat the formation of the directivity pattern many times, it takes too much time to cover all the directions. In this case, when the mobile station in the standby state is moving, it cannot follow this movement.

Even if it takes time to repeat the formation of the directivity pattern, if a control channel is transmitted simultaneously from a plurality of antennas without controlling the phase and amplitude, a plurality of channels whose phases are not managed can be obtained. Radio waves are synthesized in space, and a directivity pattern in which the directivity for each direction is extremely uneven appears. In this case, extreme variations occur in the reach distance for each direction.

An object of the present invention is to provide a base station apparatus capable of transmitting a control channel to mobile stations located in all directions while performing radio communication using an adaptive array when a communication channel is used. is there.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a base station apparatus for communicating with a mobile station through a time slot sequence in which a control channel and a plurality of communication channels are time-division multiplexed, wherein the communication channel comprises a plurality of first communication channels. The mobile station transmits using an adaptive array antenna consisting of one antenna in a directivity pattern suitable for the position of the mobile station with respect to the base station apparatus, and the control channel is made substantially uniform using a second antenna provided separately from the adaptive array antenna. This is achieved by a base station transmitting in directivity.

[0011]

FIG. 1 is a diagram showing the inside of a base station apparatus. The base station device is connected to a digital public network (not shown), can communicate in a wireless zone under the base station device, and can exchange information using the digital public network. As shown in FIG. 1, the base station apparatus includes an AD-PCM transcoder 1, a TDMA / TDD processing unit 2, a transmission circuit 3, a reception circuit 4, a transmission circuit 5, a reception circuit 6, a transmission circuit 7, a reception circuit 8, a transmission circuit Circuit 9, receiving circuit 10, antenna 17, antenna 18, antenna 19, antenna 20, antenna 2
1, a switch 22, a switch 23, a switch 24, a switch 25, and a switch 26.

The ADPCM transcodec 1 performs bidirectional conversion between a signal format transmitted in a digital public network and a 32 Kbps ADPCM signal transmitted in a wireless zone. TDMA / TD
The D processing unit 2 performs TDMA / TDD processing on the AD-PCM signal output from the AD-PCM transcodec 1, and transmits a baseband signal in which a plurality of time slots are time-division multiplexed to the transmission circuit 3 and the transmission circuit. 5, output to the transmission circuit 7 and the transmission circuit 9. Hereinafter, what kind of channel the time slot multiplexed with the baseband signal forms will be described below. FIG. 2 is a diagram showing how time slots multiplexed with a baseband signal form a communication channel and a control channel.

In FIG. 2, the horizontal axis represents the time axis, and the repetition of the numbers 1,2,3,4,1,2,3,4 on this time axis indicates the sequence of time slots appearing in time series. I have. Of these, eight time slots are TDM defined in PHS.
A frame is composed. In the PHS, the slots that make up the TDMA frame are (uplink slots 1, 2, 3, 4,
Downlink slots 1, 2, 3, 4), and a pair of uplink and downlink slots are communication channels in the PHS, and independent communication can be realized in these. Since a TDMA frame includes four such sets of time slots, 4
That is, two communication channels are multiplexed. These traffic channels are mobile station 1 if the slot 1 is uplink or downlink.
01, mobile station 102 for uplink / downlink slot 2, mobile station 103 for uplink / downlink slot 3, and so on.
Are mobile stations that have established a number of connections with the base station apparatus, so that the time slots constituting these communication channels need only be transmitted in the direction in which the mobile stations 101 to 103 exist.

FIG. 3 is a diagram showing a control channel constituted by time slots. A plurality of time slots included in the baseband signal in the first stage in the figure (1, 2, 3, 4, 4, 1, 2, 3, 4, 1, 2, 3, 4,... In the figure) Shows a time slot sequence as in FIG. 2, and the second row in the figure shows an LCCH superframe defined in the PHS. Here, the LCCH superframe includes various control channels in the PHS.

The dashed arrows in the figure indicate which of the time slots in the first stage constitute an LCCH superframe. Referring to this arrow, 5 × n mse
By arranging m time slots (time slots 4) appearing in the baseband signal every other c, the LCCH
It can be seen that a super frame is formed. FIG.
FIG. 3 is a diagram illustrating various control channels included in an LCCH superframe.

Referring to FIG. 4, the LCCH superframe includes a broadcast channel BCCH and a paging channel P1, P2, P3, P
4. It can be seen that control channels such as the logical control channel SCCH are included. The broadcast channel BCCH is provided to broadcast information for acquiring synchronization, a communication channel structure, a superframe length, and the like.

The paging channel PCH is a channel provided for calling a subordinate mobile station.
This PCH is numbered P1, P2, P3,
This is because the mobile station is divided so that it can be individually addressed to the subordinate mobile stations. The logical control channel SCCH is information for intermittently reporting control information such as information indicating the structure of a communication channel and system information.

The broadcast channel BCCH, the paging channels P1, P2, P3, P4, and the logical control channel SCCH must receive not only mobile stations in a talk state but also mobile stations in a standby state. Therefore, it is desirable to transmit the time slots constituting the LCCH superframe in all directions. Particularly worthy of explanation in this embodiment is TD
The MA / TDD processing unit 2 generates a transmission period instruction signal and a control channel instruction signal and outputs them to the switches 22 to 25 and the switch 26.

The transmission period instruction signal indicates a period during which a downstream time slot appears in the baseband signal. FIG. 5 is a timing chart showing the correspondence relationship between the time slot sequence included in the baseband signal, the transmission period instruction signal-control channel instruction signal, and the settings of the switches 22 to 26. The first row in FIG. 5 shows a time slot sequence included in the baseband signal. Of the time slot sequence in the first stage,
Eight things make up a TDMA frame.

The second row in FIG. 5 shows a transmission period instruction signal. Referring to this transmission period instruction signal, it is on only during the period when the downlink time slot appears in the first stage (see periods t1, t2, t3, t4, and t5), and all other periods are off. (Period t8, t9, t
10, t11, t12). Further, among the time slots 4 in the first stage, those that appear every 5 × n intermittent transmission periods are as follows:
Like the ones shown in FIG. 3 and FIG. 4, an LCCH superframe is configured.

The third row in FIG. 5 shows a control channel indication signal. That is, in the first stage, the time slot 4 appears every intermittent transmission period 5 × n, but only during the time slot 4 appears, the control channel indication signal is turned on (the period t21, t22, t23 is ), Other periods,
You can see that everything is off. This concludes the description of the time slot included in the baseband signal. Next, a transmission / reception system in the base station device will be described.

In the internal configuration of the base station apparatus shown in FIG. 1, the transmission circuit 3—the reception circuit 4—the antenna 17—the switch 22—the switch 26—the antenna 21 constitute one transmission / reception system. The receiving circuit 6, the antenna 18, and the switch 23 constitute one transmission / reception system. Similarly, the transmission circuit 7-the reception circuit 8-the antenna 19-the switch 24, the transmission circuit 9-the reception circuit 10-the antenna 20
The switches 25 also constitute independent transmission / reception systems. These four transmission / reception systems in the present base station apparatus transmit / receive a communication channel using an adaptive array system.

Regarding the details of the transmission / reception system, the transmission circuit 3-
Receiving circuit 4-antenna 17-switch 22-switch 2
The 6-antenna 21 will be described as an example. The four antennas 17 to 20 included in the four transmission / reception systems
Corresponds to the adaptive array antenna described in the claims. FIG. 6 is a diagram showing an internal configuration of the transmission circuit 3 and the reception circuit 4 and a connection relationship between the internal configuration and peripheral portions.

In FIG. 1, a transmission circuit 3 includes a transmission adjustment unit 11 for adjusting the amplitude and phase of the baseband signal output from the TDMA / TDD processing unit 2, and a base whose amplitude and phase have been adjusted by the transmission adjustment unit 11. A modulator 12 for modulating a band signal into an intermediate frequency signal (hereinafter abbreviated as an IF signal) and converting the IF signal into a high frequency signal (hereinafter abbreviated as an RF signal);
And a power amplifier 13 for amplifying the RF signal converted by 2 to a transmission output level.

The receiving circuit 4 amplifies a received signal induced by the antenna 17 and a demodulation for converting the amplified received signal into an IF signal and demodulating the IF signal into a baseband signal (symbol data). A modulator 15 and a reception adjustment unit 16 for adjusting the amplitude and phase of a reception baseband signal input from the demodulator 15 to generate a directivity pattern as an adaptive array. The modulation and demodulation method in the modulator 15 may be of any type as long as it is digital modulation.
This is performed by the PSK method.

The antenna 17 transmits the RF signal output from the transmission circuit 3 to the radio zone of the base station device,
This is a vertical antenna that receives radio waves transmitted in the wireless zone. The switch 22 is set to the contact C side while the transmission period instruction signal is on, and is switched to the contact D side while the transmission period instruction signal is off. Thereby, the RF signal output from the transmission circuit 3 is transmitted to the antenna 17 during the ON period of the transmission period instruction signal, and the reception signal input from the antenna 17 is transmitted to the reception circuit 4 during the OFF period of the transmission period instruction signal. Is transmitted.

The switch 26 is set to the contact B side while the control channel instruction signal is off,
The switch is switched to the contact A side while the control channel instruction signal is on. By such switching, the RF signal output from the transmission circuit 3 is transmitted to the antenna 17 during the off period of the control channel instruction signal, but the RF signal output from the transmission circuit 3 is transmitted during the on period of the control channel instruction signal. The signal is output to the antenna 21.

The antenna 21 is a vertical antenna having an antenna gain higher than that of the antennas 17 to 20 included in the adaptive array. That is,
The antenna gain of the antennas 17 to 20 is 10 dBi
However, the antenna 21 has an antenna gain of 16 dBi. Antenna gain of 10dBi, transmit power 500mW
Is an antenna gain that is permitted to be used in the base station apparatus of FIG. On the other hand, the antenna gain of 16dBi is up to 2W
This is the antenna gain when transmitting a radio wave with the transmission output of FIG.
In the Radio Law revised in 1998, the maximum transmission power of 2 W is recognized only when transmitting the control channel. Therefore, by transmitting the control channel using the antenna 21 having the antenna gain of 16 dBi, the maximum control channel can be obtained. Sent with 2W transmit power.

"DBi" is a unit representing an antenna gain (referred to as absolute gain) when an isotropic (omnidirectional) antenna is used as a reference antenna, and an antenna other than an isotropic antenna is used as a reference antenna. It is used separately from the antenna gain when it is used (referred to as "relative gain" and expressed by "dB"). Since an ideal isotropic antenna does not actually exist, an absolute gain is calculated by calculating a relative gain using a small dipole antenna as a reference antenna and multiplying the relative gain by the absolute gain of the small dipole antenna. Calculations are often used.

The details of the transmission / reception system including the transmission circuit 3 and the reception circuit 4 have been described above. Subsequently, the remaining transmission / reception systems in the base station device will be described. The antenna gain of the antenna 18, the antenna 19, and the antenna 20 is 10 dBi, which is the same as the antenna gain of the antenna 17. The gain of the adaptive array is
The approximation can be made using an antenna gain of 10 dBi of the antenna 20 and a specific gain (adaptive array gain) of 6 dB by performing the adaptive array method. According to this approximate calculation, the gain at the time of transmission when using the adaptive array is 16 dBi.

The other transmission / reception system is different from the transmission / reception system including the transmission circuit 3 and the reception circuit 4 because the switch 26 which switches to the latter transmission / reception system by the control channel instruction signal.
And the antenna 21, whereas in the former transmission / reception system, a control channel instruction signal is directly input to the transmission circuit 5, the transmission circuit 7, and the transmission circuit 9. The point is that the transmission circuit 5, the transmission circuit 7, and the transmission circuit 9 are stopped during the period in which they are on.

Based on the common points and differences between the transmission / reception systems, the communication channel and the control channel in the base station apparatus are transmitted as follows. That is, during a period in which the transmission period instruction signal is on and the control channel instruction signal is off, a speech channel appears in the baseband signal,
The communication channel is transmitted and received by an adaptive array including four transmission / reception systems using the antennas 17 to 20.

On the other hand, while the control channel instruction signal is on, the transmission circuit 5, the transmission circuit 7, and the transmission circuit 9 are in a stopped state, and the switch 26 is switched from the contact B to the contact A. It can be seen that radio waves are transmitted using only the combination with the antenna 21. Here, the antenna 21 has an antenna gain of 16 dBi, and can transmit the control channel with the same gain as the adaptive array.

FIGS. 7A to 7C are diagrams showing the settings of the switches 22 to 26 at the time of transmitting the communication channel, receiving the communication channel, and transmitting the control channel. FIG. 7A shows the state of the switch 22 when transmitting a communication channel.
FIG. 7 is a diagram illustrating settings of a switch 26. In FIG. 7A, it can be seen that the switches 22 to 25 are set to the contacts C, F, H, and J, and the switch 26 is set to the contact B.

FIG. 7B is a diagram showing the settings of the switches 22 to 26 when receiving a communication channel.
In FIG. 7B, the switches 22 to 25 are set to the contacts D, G, I, and K, and the switch 26 is
It can be seen that the contact B is set. FIG. 7 (c)
FIG. 6 is a diagram showing settings of switches 22 to 26 at the time of transmitting a communication channel. In FIG. 7A, while the switch 26 is set to the contact A side and the control channel instruction signal is on, the transmission circuit 5, the transmission circuit 7, and the transmission circuit 9 are stopped. You can see that there is.

FIG. 8 shows an antenna 17 in the base station apparatus.
FIG. 3 is a diagram showing a spatial arrangement of antennas 20 and 21. In the figure, it can be seen that the antennas 17 to 20 are radially arranged in four directions, and the antenna 21 having an antenna gain of 16 dBi is arranged in the middle. The switching of the switches 22 to 26 will be described again with reference to FIG.

The fourth stage in FIG. 5 shows the settings of the switches 22 to 25, and the fifth stage shows the transmission circuit 5,
The state of the transmission circuit 7 and the transmission circuit 9 are shown. The sixth row in FIG. 5 shows the setting of the antenna 21. Here, referring to the second stage of the figure, the transmission period instruction signal includes the periods t1, t2,
It turns out that it is ON at t3, t4, t5.

Referring to the fourth row, these periods t1, t
Of the 2, t3, t4, and t5, the switches 22 to 25 are set to the contacts C, F, H, and J during the period in which the control channel instruction signal is off. Is set on the antenna 17 side. As a result, the downlink time slots constituting the traffic channel are transmitted using the adaptive array.

On the other hand, the transmission period instruction signal includes the periods t8, t9, t1
It turns out that it is off at 0, t11, t12. Referring to the fourth row, during these periods, switch 2
2 to the switch 25 are set to the contacts D, G, I, and K sides,
At the stage, the switch 26 is set to the antenna 17 side. As a result, the uplink time slots constituting the traffic channel are received using the adaptive array.

Next, switching of the switch 26 while the control channel instruction signal is on will be described. In the third row of the figure, it can be seen that the control channel indication signal is on in the periods t21, t22, t23. Also, referring to the fifth row of the figure, these periods
At t21.t22.t23, it can be seen that the transmission circuit 5, the transmission circuit 7, and the transmission circuit 9 are in the stopped state.

Further, referring to the sixth row, switch 2
It can be seen that 6 has been switched to the antenna 21 side. Thereby, the control channel appearing in the baseband signal in the periods t21, t22, and t23 is transmitted using only the antenna 21. As described above, according to the present embodiment, the control channel appears in the baseband signal during the period in which the control channel instruction signal is on,
The control channel is transmitted by the adaptive array using only the antenna 21. Since the radio wave transmitted by the antenna 21 alone is transmitted with substantially uniform directivity, it is transmitted to the base station apparatus in all directions. The antenna gain of the antenna 21 is different from those of the other antennas 17 to 2.
Since the gain is larger than 0, the control channel can be received by a mobile station located far away from the base station apparatus.

[0042]

As described above, the present base station apparatus is a base station apparatus that communicates with a mobile station through a time slot sequence in which a control channel and a plurality of communication channels are time-division multiplexed. The mobile station transmits using an adaptive array antenna composed of a plurality of first antennas in a directivity pattern suitable for the position of the mobile station with respect to the base station apparatus, and the control channel uses a second antenna provided separately from the adaptive array antenna. Since transmission is performed with substantially uniform directivity, it is possible to cause mobile stations located in all directions as viewed from the base station apparatus to receive the control channel.

Here, the base station apparatus may include switch means for switching between the second antenna and the adaptive array antenna between the communication channel and the control channel in each time slot. This base station apparatus can share one transmission circuit among the set of the transmission circuit and the first antenna in the adaptive array, so that the circuit configuration in the base station apparatus can be simplified.

[0044] The base station apparatus includes the same number of transmitting circuits as the plurality of first antennas constituting the adaptive array antenna, and the switch means connects one of the transmitting circuits to one of the plurality of first antennas in a communication channel. And switching is performed so as to connect to the second antenna in the control channel, and the remaining transmission circuit and the remaining antenna are connected in a one-to-one relationship,
The transmission may be controlled to stop in the control channel.

Here, the second antenna may have an antenna gain higher than the antenna gain of the plurality of first antennas included in the adaptive antenna. With the second antenna, the base station apparatus can make a mobile station located far away receive a control channel.

[Brief description of the drawings]

FIG. 1 is a diagram showing an internal configuration of a base station device.

FIG. 2 is a diagram showing how time slots multiplexed on a baseband signal form a communication channel and a control channel.

FIG. 3 is a diagram showing a control channel constituted by time slots.

FIG. 4 is a diagram illustrating various control channels included in an LCCH superframe.

FIG. 5 is a timing chart showing a correspondence relationship among a time slot sequence included in a baseband signal, a transmission period instruction signal, a control channel instruction signal, and settings of switches 22 to 26.

FIG. 6 is a diagram illustrating an internal configuration of a transmission circuit 3 and a reception circuit 4 and a connection relationship between the internal configuration and peripheral portions thereof.

FIGS. 7A to 7C show a switch 22 when transmitting a communication channel, receiving a communication channel, and transmitting a control channel.
FIG. 7 is a diagram illustrating settings of a switch 26.

FIG. 8 shows antennas 17 to 2 in the base station apparatus.
0 is a diagram showing a spatial arrangement of the antenna 21. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transcodec 2 TDMA / TDD processing part 3,5,7,9 Transmission circuit 4,6,8,10 Receiving circuit 11 Transmission adjustment part 12 Modulator 13 Power amplifier 14 Low noise amplifier 15 Demodulator 16 Reception adjustment part 17- Reference Signs List 20 antenna 21 antenna 22-25 switch 26 switch

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K059 AA08 AA12 AA14 BB03 CC04 DD07 5K067 AA03 AA13 AA42 BB04 CC05 CC06 CC22 CC24 EE02 EE10 EE41 EE71 GG03 KK02 KK03

Claims (4)

[Claims] 1. A base station apparatus for communicating with a mobile station through a time slot sequence in which a control channel and a plurality of communication channels are time-division multiplexed, wherein the communication channel includes an adaptive array antenna including a plurality of first antennas. And transmitting the control channel with a directivity pattern corresponding to the position of the mobile station with respect to the base station device, and transmitting the control channel with a substantially uniform directivity using a second antenna provided separately from the adaptive array antenna. Base station device. 2. The base station apparatus according to claim 1, further comprising switch means for switching between a second antenna and an adaptive array antenna between a communication channel and a control channel in each time slot. 3. The base station apparatus includes the same number of transmitting circuits as a plurality of first antennas forming an adaptive array antenna, and the switch means sets one of the transmitting circuits to the plurality of first antennas in a communication channel. And switching is performed to connect to the second antenna in the control channel. The remaining transmission circuit and the remaining antenna are connected in a one-to-one relationship, and the control channel 3. The base station apparatus according to claim 2, wherein the transmission is controlled to stop. 4. The base station apparatus according to claim 1, wherein the second antenna has an antenna gain higher than an antenna gain of a plurality of first antennas included in an adaptive antenna.