JPH06188800A - Radio repeating system - Google Patents

Abstract

PURPOSE:To make the gain of an amplifier large even when the loss of sneak path between both antennas of a repeating device is small after decoding a received signal by the repeating device and by sending the signal while delaying it by a certain period of time. CONSTITUTION:When a down signal is repeated, the signal is sent from a base station to a mobile station with a transmission slot 102. This signal is received by the repeating device with a reception slot 112 and then sent to the mobile station with a transmission slot 122 after being delayed by the certain time. When an up signal is repeated, the signal is sent from the mobile station to the base station with a transmission slot 133. This signal is received by the repeating device with a reception slot 123, and sent to the base station with a transmission slot 113 after being delayed by the certain time. Thus, a communication between the base station and mobile station is made through the repeating device. The reception slots 112 and 123 overlap with each other at the repeating station, so the signal sent by the base station as a desired wave and the signal sent by the mobile station with the transmission slot 133 as a disturbing wave are received with the slot 112.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay system for wireless signals in a wireless section of a mobile communication system.

[0002]

2. Description of the Related Art As a countermeasure against a radio dead zone such as a tunnel in a car telephone, a method using a repeater using a common amplifier has been conventionally adopted.

FIG. 9 is a diagram showing the configuration of such a conventional relay system, in which 900 is a relay, 901 is a base station, 902 and 904 are antennas, 903 and 906 are amplifiers, and 905 is a mobile unit. Reference numeral 907 represents a tunnel.

In the figure, the repeater 900 is a base station 9
The radio wave from 01 is received by the base station antenna 902,
Common amplification is performed by the downlink amplifier 903, and the antenna 9 for mobile stations is used.
In 04, it re-radiates toward the mobile station 905 in the tunnel, and conversely, the radio wave from the mobile station 905 in the tunnel is received by the mobile station antenna 904, is commonly amplified by the upstream amplifier 906, and is transmitted by the mobile station antenna. Base station 902 at base station 901
By re-radiating toward the
05 and the base station 901 can communicate with each other.

[0005]

Since the conventional relay system as described above is a direct relay which re-radiates at the same frequency, radio waves received by the antenna 902 for the base station and re-radiated by the antenna 904 for the mobile station. Will be received by the base station antenna 902 although there is a wraparound loss. Therefore, if the gain from the base station antenna 902 to the mobile station antenna 904 is G dB and the sneak loss is L dB, oscillation occurs if G> L.

Therefore, in order to operate the repeater stably, it is necessary to set G << L. The condition is good if the mobile station antenna is in a tunnel, etc., and L is 70 to 80 dB.
As a result, G can be about 60 dB. However, the condition is bad if the antenna for the base station and the antenna for the mobile station are not cut off, L may be about 40 to 60 dB, and G is only about 30 db. There was a problem that was not.

The present invention has been made in order to solve such a conventional problem, and provides a relay system capable of increasing the gain of an amplifier even when the wraparound loss between both antennas of a relay device is small. Is intended.

[0008]

According to the present invention, the above problems can be solved by the means described in the claims. That is, the present invention is a relay system in a mobile communication system in which a base station and a mobile station communicate in a time division manner, in which a relay device receives a radio wave transmitted from a base station,
After decoding, it stores the decoded signal and transmits it to the mobile station after a certain time so that the transmission time does not overlap with the reception time, while receiving the transmission radio wave from the mobile station. The wireless relay system is characterized in that after decoding, the decoded signal is stored and transmitted to a base station after a certain time so that the transmission time does not overlap with the reception time.

[0009]

According to the present invention, in the relay device, the signal transmitted from the base station is decoded, delayed for a predetermined time, and then transmitted to the mobile station at the time when the mobile station normally transmits. Also, similarly, in the relay device, the signal transmitted by the mobile station is received,
After decoding and delaying for a certain period of time, the data is transmitted to the base station at the time when the base station normally transmits.

That is, in the prior art, a relay device receives and amplifies a signal at the same time as it receives the signal, but in the present invention, by preventing the received time and the transmitted time from overlapping, the transmitted signal is The structural feature is that it does not go around to the receiving side.

The operation of the present invention will be described below with reference to FIG. FIG. 1 shows one channel TDD for ease of explanation.
The case is taken as an example. In the figure, 101 is a base station timing, 102 is a transmission slot, and 103 is a reception slot.

Reference numeral 111 is a timing for the base station of the relay device, 112 is a receiving slot, and 113 is a transmitting slot. 121 is a timing for the mobile station of the relay device, 122 is a transmission slot, and 113 is a reception slot.

Reference numeral 131 denotes the timing of the mobile station, which is 13
Reference numeral 2 indicates a receiving slot and 133 indicates a transmitting slot. The downlink signal is relayed from the base station through the transmission slot 102.
To send a signal to the mobile station. This signal is received by the relay device in the reception slot 112, and after a certain time delay, transmitted to the mobile station in the transmission slot 122.

For relaying the upstream signal, the mobile station transmits the signal to the base station in the transmission slot 133. This signal is received by the relay device in the reception slot 123, and after a fixed time delay, transmitted to the base station in the transmission slot 113.

With the above operation, the base station and the mobile station can communicate with each other via the relay device. In the relay device,
Since the receiving slot 112 and the receiving slot 123 overlap, the signal transmitted by the base station, which is the desired wave, and the signal transmitted by the mobile station, which is the interfering wave, in the transmitting slot 133 are received in the receiving slot 112.

However, the antenna for the base station and the antenna for the mobile station are usually directional antennas and are installed so as not to interfere with each other. Therefore, the signal received by the receiving slot 112 is a desired wave >> interfering wave. Therefore, no problem occurs. Similarly, reception slots 123, 103 and 132
The signal received at is also the desired wave >> interfering wave, so no problem occurs.

[0017]

2 is a block diagram showing an example of the configuration of an apparatus for carrying out the present invention, in which 211 is a base station antenna and 20
Reference numeral 1 is a duplexer that distributes radio waves for transmission and reception, 202 is a downlink receiver, 203 is a downlink delay circuit, 204-1 and 204-2 are timing extraction circuits, 205 is a control unit, 206 is a downlink transmitter, and 207 is a duplexer. , 212 is a mobile station antenna,
Reference numeral 208 is an upstream receiver, 209 is an upstream delay circuit, and 210 is an upstream transmitter.

FIG. 3 shows the frame structure of an embodiment of the present invention.
4 shows the timing of the control channel in the case of continuous transmission of the embodiment, FIG. 5 shows the timing of the control channel in the case of intermittent transmission of the embodiment, and FIG. 6 shows the timing of the communication channel of the embodiment.

FIG. 7 shows the timing of the mobile station, and FIG. 8 shows the relay timing of another embodiment of the present invention. Embodiments of the present invention will be described below with reference to these drawings.

(1) According to FIG. 3, T in the case of the first embodiment
The frame structure of the DMA-TDD signal will be described (this embodiment shows the case of 4 channels and 8 slots). Reference numeral 301 denotes a frame structure of one cycle, and the cycle is T. Since one frame is divided into transmission and reception, each becomes T / 2. 302 is a transmission slot, which is further divided into four, and 302-n indicates its nth slot.

In this specification, the transmission slot is shown on the positive side and the reception slot is shown on the negative side for the sake of convenience. Also, 3
Reference numeral 03 is a reception slot, and like 302, this is further divided into four, and 303-n indicates its nth slot. The period of each of these slots is t. That is,
T / 2 = 4 × t.

(2) The operation of the embodiment will be described with reference to FIGS. The radio wave transmitted from the base station is received by the base station antenna 211 and is input to the downlink receiver 202 by the duplexer 201. The signal decoded by the downlink receiver 202 is input to the downlink delay circuit 203 and the timing extraction circuit 204-1.

On the other hand, the signal delayed by four slots in the delay circuit 203 is modulated by the downlink transmitter 206 and shared by the duplexer 207.
And is transmitted from the mobile station antenna 212 to the mobile station.

The radio wave transmitted by the mobile station is received by the mobile station antenna 212, passes through the duplexer 207, and goes up the receiver 2.
08, is decoded, is delayed by 4 slots in the delay circuit 209, is modulated in the upstream transmitter 210, and is shared by the duplexer 20.
1, the signal is transmitted to the base station by the base station antenna 211.

The output of the downlink receiver 202 is input to the timing extraction circuit 204-1 and the control unit 205. Timing extraction circuit 204-1 uses signals 403 and 40
4 and the timing extraction circuit 204-2 also extracts the signals 405 and 406. The control unit 205 controls the output and signals 405, 406-1 to 4 of the downlink receiver 202.
06-4 to 408-1 to 408-4 and 409-1
~ 409-4 are created.

The numeral 401 in FIG. 4 indicates the timing of signals transmitted and received by the base station.
Reference numeral 02 denotes a downlink control channel slot transmitted by the base station, and reference numeral 407 denotes an uplink control channel slot corresponding to 402, which is a slot for receiving the uplink control channel from the mobile device. The base station is constantly receiving 407 slots.

(3) The operation of the timing extraction circuit and the control unit will be described. In this embodiment, the relay device is the TD of the base station.
By grasping the timing of the MA and operating in synchronization with it, the transmission timing of the base station or mobile station can be predicted, so even if radio waves are transmitted from these stations to the relay device, the signal is immediately transmitted to the relay device. , Can be received, and relay can be realized efficiently.

In order to grasp the timing of the TDMA of the base station, it is necessary to decode and decode the signal transmitted by the base station. The signals transmitted by the base station are roughly classified into a control channel and voice for call control. There are two types of communication channels for transmitting such as. The method of extracting timing from these signals is shown below.

(4) A method of extracting the timing of the base station from the signal of the control channel or the communication channel will be described. Since the slot number (corresponding to "n" of 302-n in FIG. 3) is encoded in each signal of the control channel or the communication channel, the signal is decoded and synchronized with the signal of the control channel or the communication channel. By creating, the timing of the base station can be extracted.

However, when the communication of the communication channel ends, both the base station and the mobile station stop the transmission of radio waves, so it is generally not possible for the relay device to receive the signal of the communication channel and extract the timing. This is not preferable because it leaves certainty. Hereinafter, a case where the timing is extracted from the control channel will be described.

The timing extraction circuit 204-1 decodes the control channel signal 402 transmitted intermittently by the base station, and from this, the control channel timing 40 of the base station is decoded.
3 and slot clock 404 are created. These signals are input to the timing extraction circuit 204-2, where
RX timing 405 and TX timing 406-1 to
406-4 is created.

Next, RX timing 405, TX timings 406-1 to 406-4 and upstream receiver 208
And the decoded output of the downlink receiver 202 are input to the control unit 205. The control unit 205 determines from these signals the slot-on signals 408-1 to 408- of the downlink transmitter.
4 and slot transmitter on-signals 409-1 to 409-1
409-4 is created.

(5) The operation timing of the relay device according to the embodiment of the present invention will be described with reference to FIGS. The RX timing 405 is the transmission timing of the base station when the level is H. Therefore, it is also the reception timing of the relay device and the transmission timing of the mobile station. In the relay device, the receiver is not limited to the control channel and the communication channel, and it is necessary to be ready to immediately receive the radio wave.
There is no problem if 2 and 208 are always on, but when the level of RX timing 405 is H, receivers 202 and 2
Efficiency can be increased by turning on 08.

In addition, TX timings 406-1 to 406
-4 is the reception timing of the base station when the level is H, and also the transmission timing of the relay device and the reception timing of the mobile station. That is, TX timing 406
-N is a transmission timing of slot n, and the relay device turns on slot n of transmitter 206 or transmitter 210 when the level of TX timing 406-n is H and there is a signal to be relayed.

Since the delay circuit is required to delay all the signals in slots 1 to 4, the power supply is always on.

(6) The operation of the control channel will be described. The embodiment of FIG. 4 is an example in which the base station continuously transmits every slot, and FIG. 5 shows the case of transmitting every slot. Although the second slot is used as the position of the slot, any of positions 1 to 4 may be used.

Further, the control channel needs to relay a sporadic signal. The state of relaying by two examples will be described below.

(7) The timing when the transmitter is turned on in the case of FIG. 4 will be described. FIG. 4 shows the case where the base station continuously transmits the control channel signal, and the control unit 205 uses the signal from the downlink receiver 206 and the signal from the uplink receiver 208 to turn on the slot of the downlink transmitter. Signal 408-
2 and the uplink transmitter slot-on signal 409-2 are turned on as shown in FIG. 4 or FIG. 5, the relay device can relay the signals of the uplink and downlink control channels.

(8) The timing when the transmitter is turned on in the case of FIG. 5 will be described. FIG. 5 shows a case where the base station transmits the control channel signal 501 intermittently, and the downlink control channel signal is every other frame (502-1 and 502).
-3). Since the relay device needs to relay the signal of the second slot, it is possible to use 502-1 and 502.
The slots of 508-2-1 and 508-2-3 corresponding to -3 are set to H.

Reference numeral 510 is a signal transmitted by the mobile station, and 511 is a transmittable slot of the mobile station. Here, only 511-2 is transmitted. Since the relay device needs to relay the signal in the second slot, the slot 509-2-2 corresponding to 511-2 is set to H. As described above, the relay device delays the received control channel signal and turns on the transmitter so that the control channel signal can be relayed.

(9) The details of the timing of the communication channel according to the embodiment of the present invention will be described with reference to FIG. FIG. 6 shows the operation timing of a communication channel for transmitting a signal such as voice, and the base station is currently communicating with the mobile station using the first slot. Here, 601 is the timing of the base station, 602 is the transmission slot of the communication channel, and 603 is the reception slot of the communication channel.

Further, 611 is a timing for the base station of the relay device, 612 is a receiving slot, 613 is a transmitting slot, and the signal of 602 transmitted by the base station is 6
The signal 613 received by the relay device 12 and transmitted by the relay device is received by the base station 603, and the base station and the relay device can communicate with each other.

Further, 621 is a timing for the mobile station of the relay device, 622 is a transmission slot, and 623 is a reception slot. 631 is the timing of the mobile station,
632 is a receiving slot, 633 is a transmitting slot,
The 633 signal transmitted by the mobile station is received at 623,
The signal 622 transmitted by the relay device is received by the base station 632, and the mobile station and the relay device can communicate with each other.

The signal received at 612 in the above-mentioned relay device is delayed for a specified time, here, 4 slots, and then 622
The signal received at 623 and received at 623 is similarly transmitted at 613 after a delay of a specified time.

At the above timing, the base station, the relay device, and the mobile station operate, and the relay device can relay the signal of the communication channel.

(10) The transmission of the communication channel will be described. The relay device can receive all the radio waves transmitted by the base station that relays. Therefore, when a mobile station exists in an area other than the area to be relayed by the relay device and the mobile device and the base station are communicating with each other through the communication channel, the relay device selects the downlink receiver, delay circuit, and transmitter. When it is turned on, radio waves are relayed even if there is no mobile station in the area targeted by the relay device, which is wasteful.

Therefore, according to the present invention, when the relay device can receive the radio wave of the upstream communication channel from the mobile device and can receive the downlink communication channel of the same channel, the upstream transmitter and the downstream transmission. By turning on the device, the relay device can efficiently relay the radio wave only to the mobile stations in the area to be relayed.

(11) A case of a frame structure different from that of this embodiment will be described. In the embodiment described above, 4CH T
With the frame structure of DMA-TDD, from the viewpoint of the mobile station,
The timing can be expressed as shown in FIG. That is, FIG.
In the case of t1 = t2 = T / 8 t3 = t4 = 3 × t1, the frame structure is the same as that of the digital cordless telephone called PHP in Japan, and the same method can be applied.

Further, in the present invention, t1, t2, t
3 and t4 may be any value of 0 or more. For example, if t1 = t2 = t3 = T / 3 t4 = 0, then 3CH3 slot TDMA has the same frame structure as the digital car telephone system called JDC in Japan, and t1 = t2 = T / 8 t3 = If t1 × 2 t4 = t1 × 4, then it is an 8-slot TDMA, which is the case of the European unified car telephone system called GSM, and the present invention is also applicable to these two examples.

The case of the JDC system will be described below as another embodiment.

(12) Another embodiment will be described. This embodiment is basically the same as the previous embodiment except that t1 = t2.
Since = t4 = T / 3 and t3 = 0, the above-described embodiments can be applied. The relay timing will be described with reference to FIG.

In the figure, reference numeral 801 is the timing of the base station, 802 is a transmission slot, 803 is a reception slot, and 804 is an empty slot. Reference numeral 811 is a timing for the base station of the relay apparatus, 812 is a reception slot, 813 is a transmission slot, and 814 is an empty slot. The signal of the transmission slot 802 transmitted by the base station is received by the reception slot 812, and the relay apparatus The signal of the transmission slot 813 transmitted by is received by the reception slot 803.

Reference numeral 821 is a timing for the mobile station of the relay device, 822 is a transmission slot, 823 is a reception slot, and 824 is an empty slot. 831 is the timing of the mobile station, 832 is the receiving slot, 833
Is a transmission slot, and 834 is an empty slot. The signal of 833 transmitted by the mobile station is received at 823, the signal of 822 transmitted by the relay device is received at 832 of the mobile station, and the mobile station and the relay device communicate with each other. it can.

In this embodiment, the receiving slot 812 is
The signal received at is delayed by one slot, and the transmission slot 82
The signal transmitted in 2 and received in the receiving slot 823 is 2
It is delayed by a slot and transmitted in a transmission slot 813.

As described above, the base station, the relay device, and the mobile station operate at the timing shown in FIG. 8, and the relay device can relay the signal of the communication channel.

[0056]

As described above, according to the present invention,
After the received signal is decoded by the relay device, it is transmitted after delaying for a certain period of time, so even if the amount of coupling between the antennas is a little large, the radio waves can be amplified without oscillating. There is an advantage that it can be applied to a place with a large amount of binding.

In the first embodiment described above, the delay time is T /
2, that is, 1/2 of the TDMA cycle, but the delay time is m times (T / 8) (m is 1 to 7 (in this embodiment, m =
Even in 4)), since the transmission time and the reception time do not overlap with each other, the own slot does not oscillate.

Further, m = 4 in another embodiment described later.
In the case of 1, there is an advantage that the transmission time and the reception time do not completely overlap in all the slots in the relay device, that is, the transmission time is not transmitted at the time of reception, so that the sensitivity is not suppressed at all.

It should be noted that the present invention can be applied to all systems as long as the TDD system has one or more channels.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an operation of the present invention.

FIG. 2 is a block diagram showing an example of an apparatus for implementing the present invention.

FIG. 3 is a diagram showing a frame structure according to an embodiment of the present invention.

FIG. 4 is a diagram showing a timing of a control channel in the case of continuous transmission.

FIG. 5 is a diagram showing control channel timing in the case of intermittent transmission.

FIG. 6 is a diagram showing timings of communication channels.

FIG. 7 is a diagram showing timing of a mobile station.

FIG. 8 is a diagram showing a relay timing according to another embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a conventional relay system.

[Explanation of symbols]

101, 601, 801 Base station timing 102, 113, 122, 133, 302, 613, 6
22, 633, 802, 813, 822, 833 Transmission slots 103, 112, 113, 132, 303, 612, 6
23, 632, 803, 812, 823, 832 Reception slot 111, 811 Timing of relay device for base station 121 Timing of relay device for mobile station 131, 631, 831 Timing of mobile station 201, 207 Duplexer 202, 208 Receiver 203,209 Delay circuit 204-1, 204-2 Timing extraction circuit 205 Control unit 206,210 Transmitter 211,212 Antenna 301 One-cycle frame structure 401 Timing of signals transmitted and received by base station 402, 407, 508 2-1, 508-2-3, 5
09-2-2 control channel slots 403 to 405, 406-1 to 409-4 signals 501, 502-1 to 502-4 base station control channel signals 510 mobile station signals 511-1 to 511- 4 Mobile Station Transmittable Slots 602 Communication Channel Transmission Slots 603 Communication Channel Reception Slots 611 Relay Device Base Station Timings 621, 821 Relay Device Mobile Station Timings 804, 814, 824 Empty Slots

Claims (1)

[Claims] 1. A relay system in a mobile communication system in which a base station and a mobile station communicate in a time division manner, wherein a relay device receives and decodes a radio wave transmitted from a base station, and then the decoded signal. ), And transmits it toward the mobile station after a certain time so that the transmission time does not overlap with the reception time. Meanwhile, after receiving the radio wave transmitted from the mobile station and decoding it,
A wireless relay system characterized in that the signal after the decoding is stored and transmitted to a base station after a certain time so that the transmission time does not overlap with the reception time.