JP2002027534A - Base station apparatus of radio communication system and timing adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically control the transmission timing of up-frame and down-frame between the respective base station apparatus, in order to enable simultaneously transmitting and receiving of plural stations in radio communication system constituted of main station equipment and a plurality of base station apparatuses which are connected in a tree type. SOLUTION: A base station apparatus 3 is provided with a GPS receiving means 11, a radio transmission timing calculating means 12, a radio transmission delay means 13 and a radio transmitting and receiving means 14. The radio transmission timing calculating means 12 measures the GPS time designated by the main station equipment 1 and the delay time until the down-frame having a number which is designated in the same way by the main station equipment reaches a self station, and set a time wherein the delay time of the self station is subtracted from the maximum delay time corresponding to the delay time of the most distant base station apparatus, in the radio transmission delay means 13. Thereby simultaneous transmission of a plurality of stations is performed.

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 and a timing adjustment method capable of simultaneously transmitting and receiving multiple stations in a wireless communication system having a plurality of base station apparatuses connected in a tree to one head office apparatus. It is about.

[0002]

2. Description of the Related Art When a plurality of base stations connected in a tree-like manner to one head office apparatus at the same time to enable multi-station simultaneous transmission for transmitting radio signals at the same time, a GPS (Global Positioning System) is used.
There is a method of transmitting data in synchronization with the time of an ositioning system (for example, Japanese Patent Application Laid-Open No. H8-307932).

When a plurality of base stations receive radio waves transmitted from one mobile station, diversity reception (site diversity) by the plurality of base stations is controlled by controlling uplink transmission delay between links. Can be made possible.

[0004] The tree-like structure referred to here is a multi-level network in which the head office device is the highest order. When focusing on a certain base station device, the number of the upper station is one, while that of the lower station is one. There are n (1 ≦ n) stations, which means a network that can branch only to a lower route.

[0005]

However, as in the prior art, when radio transmission is performed in synchronization with the GPS time, the GP
It was necessary to generate a pulse signal having the same one-second cycle as the S time in the base station apparatus, and a corresponding GPS observation time and synchronization maintaining means were required.

In addition, when performing site diversity by simultaneous reception of multiple stations, if a star-type uplink timing correction method is applied to a system that performs a tournament system in a tree form as it is, extra processing time may occur.
When the base station device is added or the route of the link line is changed, if the arrangement or the delay time of the base station device greatly changes, there is a problem that a great setting cost is generated.

In a system in which the base station devices are connected in a tree shape, only the distribution is required for the downlink, but for the uplink, the route is narrowed down in a tournament manner. If there is, if it is not possible to multiplex, it is necessary to select from which route to relay the upstream frame arriving to the upper station, but at this time, the method of selecting the upstream frame arriving even earlier and relaying it However, since an upstream frame received by a base station device close to the head office device is more likely to be relayed, there is a problem that an upstream frame received in a better condition by a lower station cannot be relayed to the head office.

The present invention has been made to solve such a conventional problem, and in realizing simultaneous multi-station transmission / reception, the timing adjustment between base station apparatuses is automated, so that the periodic An object of the present invention is to provide a base station apparatus and a timing adjustment method for a wireless communication system capable of easily adding a base station apparatus and establishing good channel quality.

[0009]

According to the present invention, there is provided a radio communication system comprising a base station apparatus for transmitting a digital signal in a fixed cycle frame unit between a head office apparatus and a plurality of base station apparatuses connected in a tree shape. In a communication system, a headquarters apparatus and a base station apparatus include a reference signal receiving unit that receives a signal that can recognize the same time for all wireless communication systems, a wireless transmission timing calculating unit, a wireless transmission delay unit, and a wireless transmitting unit. Wherein the wireless transmission timing calculating means comprises:
The difference between the reference signal obtained from the reference signal receiving means and the arrival time of the downlink frame transmitted from the head office device is measured and reported to the head office device, and the time difference reported from the head office device is equal to or greater than the maximum value of the time difference. The wireless transmission unit performs multi-station simultaneous transmission by setting a value obtained by subtracting the measured time difference from the value as a delay time in the transmission delay unit.

With this configuration, each base station device sets a value obtained by subtracting the delay time of its own station from the maximum delay time notified simultaneously from the head office device as the delay time of its own station, so that each base station device transmits the value from the head office device. By wirelessly transmitting the downlink frame that has been delayed by this delay time, multi-station simultaneous transmission can be performed at the same time from all base station apparatuses.

A base station of a wireless communication system according to the present invention is a base station in a wireless communication system for transmitting a digital signal in a frame unit of a fixed period between a head office and a plurality of base stations connected in a tree. The apparatus includes: a wireless receiving unit that receives a radio wave from the mobile station device; and a delay correction unit that delay-controls a receiving route from the wireless transmitting / receiving unit and an upstream frame from a lower route to which a lower station is connected for each route. Means, frame synchronization comparing means for controlling the delay time of the delay correction means for synchronizing the upstream frame timing from each path, and selecting the frame of each path delayed by the delay correction means and transferring it to the upper station. When the transmission wave of the mobile station device is received simultaneously by a plurality of base station devices, the plurality of uplink frames are transmitted to a base station device having a lower route. Having a configuration in which multiple stations simultaneously received by aligning the timing at confluence with are.

[0012] With this configuration, when transmission waves of the mobile station apparatus are received simultaneously by a plurality of base station apparatuses, the plurality of uplink frames are synchronized at the time of merging at the base station apparatus having a lower route so as to be duplicated. Station simultaneous reception can be realized.

A timing adjusting method for a wireless communication system according to the present invention is directed to a wireless communication system for transmitting a digital signal in a frame unit of a fixed cycle between a head office apparatus and a plurality of base station apparatuses connected in a tree shape. The base station apparatus measures the time difference between the arbitrary reference time and the downstream frame arrival time, and among the plurality of base station apparatuses, the base station apparatus having no lower route notifies the head office apparatus of the measured time difference as delay information. Then, the headquarters apparatus notifies the maximum value of the notified delay information to the plurality of base station apparatuses, and the plurality of base station apparatuses subtract the time difference measured by the own station from the notified maximum value of the delay information. The value is set as the wireless transmission delay time, and the plurality of base station apparatuses transmit the frame transmitted from the head office apparatus after delaying the wireless transmission delay time, thereby transmitting the multi-station simultaneously. And performs.

According to this method, each base station device sets a value obtained by subtracting the delay time of the own station from the maximum value of the delay information broadcasted simultaneously from the head office device as the delay time of the own station device. Is transmitted wirelessly after delaying the downlink frame transmitted from the base station apparatus by this delay time, so that multi-station simultaneous transmission that can be transmitted at the same time from all base station apparatuses can be performed.

According to the timing adjusting method for a wireless communication system of the present invention, when a base station apparatus having no lower route notifies the head office apparatus of the delay information, the base station ID of its own station is added to the delay information to obtain a higher order. When the base station apparatus having the lower path receives the delay information with the base station ID from the base station apparatus having no lower path, the base station apparatus adds the base station ID of the own station to the base station apparatus and transmits the information to the upper path. To transfer.

According to this method, when the head office device obtains the delay information, it becomes possible to simultaneously recognize the topology of the base station device.

In the timing adjusting method for a wireless communication system according to the present invention, a plurality of base station devices add the position information obtained from the GPS together with the base station ID of the own station to the delay information and transfer the information to the head office device. The station device constructs a connection state diagram including a geographical positional relationship by collating with the map data.

According to this method, each base station device adds the GPS position information to the delay information to be notified to the head office device and sends the information, so that the head office device recognizes the connection state including the geographical positional relationship. Can be done.

The timing adjustment method for a wireless communication system according to the present invention is directed to a wireless communication system for transmitting a digital signal in a frame unit of a fixed period between a head office device and a plurality of base station devices connected in a tree shape. The base station apparatus having a path compares the upstream frame timing and its frame number received by each lower path and its own radio receiving means, and provides each lower path so that the frame timing of the same frame number matches. The delay correction means is adjusted, and an uplink frame on an arbitrary or predetermined route is selected and relayed to an upper station to perform multi-station simultaneous reception.

According to this method, when a plurality of base station apparatuses receive the transmission wave of the mobile station apparatus, the timing is adjusted until the upstream frame reaches the head office apparatus, so that multi-station simultaneous reception is realized. It will be.

According to the timing adjusting method for a wireless communication system of the present invention, when an uplink frame from a lower route is compared with a frame received by a wireless receiving unit of the own station and selected,
This relays the upstream frame of the route whose line quality is estimated to be the best to the upper station.

According to this method, in a state in which multi-station simultaneous reception is possible, the receiving base station apparatus adds reception quality information to the uplink frame, compares the reception quality information included in the uplink frame, and compares the reception quality information with the uplink frame. By selecting a frame and relaying it to an upper station, when a transmission wave from a certain mobile station device is received simultaneously by a plurality of base station devices, an uplink frame received by a base station device having higher reception quality is automatically transmitted. This allows for site diversity to be selected.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram of a radio communication system to which the present invention is applied.
1 shows a configuration in which a plurality of base station apparatuses 2 to 7 are connected in a tree shape by a dedicated digital link line. Further, the base station devices 2 to 7 are provided with wireless transmission / reception means for performing wireless communication with the mobile station devices 8 to 9, and the head office device 1 and the base station devices 2 to 7 are transmitted from the GPS satellite device 10. GPS receiving means for receiving the radio wave of Then, as a communication system, a TDMA (Time Division Multiple A
ccess) method.

In this radio communication system, specifically, the base station device 2 and the base station device 7 are connected below the head office device 1, and the base station device 3 and the base station device 3 are connected below the base station device 2. 6 are connected, and the base station apparatus 4 and the base station apparatus 5 are connected below the base station apparatus 3. The link line connecting each base station device is slave-synchronized with the upper station (this is called network synchronization), and the transmission delay by the link line does not change after network synchronization.

Further, F1 is assigned to the downlink radio channel frequency between the base station devices 2 to 7 and the mobile station devices 8 to 9, and F2 is assigned to the uplink radio channel frequency. The uplink F2 is synchronized with the downlink F1. Sent. Uplink and downlink signals are continuously transmitted in frame units, and the wireless transmission / reception means transmits uplink frames in synchronization with the downlink frames. It is assumed that the vertical frame synchronization between the base station links has already been established (it indicates a state in which the bit contents of the downlink and uplink transmission frames can be read).

In the downlink, each of the base station apparatuses 2 to 7
Distributes the signal from the upper station to the base station on the lower route and transmits it wirelessly. At this time, if the timing of the transmission wave F1 (4-8) from the base station apparatus 4 to the mobile station apparatus 8 and the transmission wave F1 (5-8) from the base station apparatus 5 to the mobile station apparatus 8 deviate to some extent, for example. , F1 (4-8) and F1 (5
The transmission timings of F1 (4-8) and F1 (5-18) must be the same, since (1-8) becomes an interference wave with each other and may not be able to be received normally by the mobile station device 8. For this purpose, radio transmission is not performed at the timing when a signal from the upper station is transmitted to the lower route, and in consideration of downlink transmission delay, by delaying radio transmission until reaching the lowest base station device, A plurality of base stations can transmit the same signal at the same time. Such transmission of the transmission wave F1 from a plurality of base station apparatuses at the same timing is referred to as multi-station simultaneous transmission.

In the uplink, each of the base station apparatuses 2 to 7
Relays the uplink signal received by the lower station or the uplink signal received by the own station to the upper station. Here, when the uplink signal F2 is transmitted from the mobile station device 9, the uplink signal received by the base station device 5 is F2 (9-5), and the uplink signal received by the base station device 6 is F2 (9-6). Then, even if the timings received by the base station apparatuses are the same, the base station apparatus 2 which is the higher-order station has F2 (9-5) and F2 (9-) due to the difference in transmission delay for each route. The arrival timing of 6) may be shifted. When the arrival timing is shifted in this way, the base station apparatus 2 sets the F2 (9-
A state in which 5) and F2 (9-6) can be recognized as the same uplink signal F2 is called multi-station simultaneous reception.

In this radio communication system, in order to realize multi-station simultaneous transmission and multi-station simultaneous reception, timing adjustment between base stations is automated at low cost, and periodic timing correction and expansion of base stations are performed. To facilitate
Try to establish good line quality.

FIG. 2 is a block diagram showing a configuration of a base station apparatus for realizing simultaneous transmission of multiple stations, and shows the base station apparatus 3 as an example. The other base station devices 2 and 4 to 7 have the same configuration.

The base station apparatus 3 has a GPS signal receiving means 11 for receiving a radio wave from the GPS satellite apparatus 10 as a reference signal receiving means, and a base station apparatus 1 for receiving the reference signal until the downstream frame transmitted from the head office apparatus 1 arrives. Wireless transmission timing calculating means 12 for measuring the time difference between the wireless communication apparatuses, wireless transmission delay means 13 for delaying the wireless transmission timing in order to perform multi-station simultaneous transmission, and wireless transmitting / receiving means 14 for performing wireless transmission / reception with the mobile station apparatus. And a route selecting means 16 for selecting either the wireless transmitting / receiving means 14 of the own station or the upstream frame from the lower station and sending it to the upper station.

The frame from the base station apparatus 2 which is the upper station is transmitted to the GPS time correction means 12 and the radio transmission delay means 13
And transmitted to the base station apparatuses 4 and 5 as lower stations.

Next, referring to the explanatory diagram shown in FIG.
A method for adjusting the timing of simultaneous transmission of multiple stations in the wireless communication system according to the present embodiment will be described.

First, the head office device 1 is configured as shown in FIGS.
As shown in (b), an arbitrary UTC time (hereinafter, GP time) obtained from a GPS signal received from the GPS satellite device 10
S time), a down frame number n to be transmitted after Δt <0> seconds, and a frame length a seconds,
Immediately after the GPS time t + x seconds, a downlink frame number m to be transmitted from the head office device 1 is calculated, and each base station device i
(I = 2, 3,..., 7), t + x,
Notify m as the measurement frame number.

However, the scheduled measurement time t + x is necessary and sufficient for all the base station apparatuses to receive the notification of the measurement scheduled time t + x and the measurement frame number m from the head office apparatus 1 before t + x seconds and prepare for measurement. And the measurement frame number m is m = n + int {(x-Δt <0>) / a}.

Next, as shown in FIG. 3C, the radio transmission timing calculating means 12 provided in the base station device i
The time difference Δt <i> from when the PS time reaches t + x until the downstream frame reaches its own station is measured, and the measurement results of the terminal base stations 4 to 7 having no base station on the lower route To the head office device 1.

The headquarters apparatus 1 transmits the notified delay time Δt
From <i>, the maximum value Δt <max> is calculated and reported to each base station apparatus i.

The wireless transmission timing calculation means 12 of each base station apparatus i calculates a value equal to or greater than the value obtained by subtracting the delay time Δt <i> of the own station from the notified maximum value Δt <max>. The delay time of the means 13 is set. As a result, as shown in FIGS. 3D and 3E, the downstream frame from the headquarters apparatus 1 receives “Δt <max> −Δt <i” at the wireless transmission delay unit 13 of each base station apparatus i. >> After the delay, the radio transmission / reception means 14 transmits the radio transmission timing, so that the radio transmission timing of the base station apparatus i is aligned with the radio transmission timing of the farthest base station apparatus, and the multi-station simultaneous transmission from all base station apparatuses is performed. It will be sent.

In this embodiment, the delay time Δt <i> is calculated from the difference between the GPS time and the downstream frame arrival time. However, it is assumed that the headquarter apparatus 1 and all base station apparatuses have the same time. As long as it is a signal such as a radio wave or light that can be notified, the procedure of notifying the base station device of the scheduled measurement time and the measurement frame number to each base station device remains unchanged. it can. For example, G
As a system close to the PS, there is a low orbit satellite position information system, but a system such as an optical beacon can be substituted.

(Embodiment 2) FIG. 4 shows each base station apparatus i
When there is no lower station of the own station, the measurement result “Ei” of the downlink transmission delay time from the head office apparatus 1 to the own station is notified in an upstream frame to the head office apparatus 1 and notified. The base station device that relays the
FIG. 13 is a configuration diagram illustrating an embodiment in which “00i”, which is D, is added to an upstream frame. In the figure, "()"
Is a transmission unit of an upstream frame in each route, and “/” is a symbol indicating a branch of the route.

In this example, the base station apparatuses 4 to 7 are located at the end, and the base station IDs 004 to 007 of the base stations are added to the delay information E4 to E7 of the base station apparatuses 4 to 7, respectively. It shows a state of transmitting to a station.

In the base station apparatuses 2 and 3 having lower routes,
When the delay information with the base station ID comes from the lower route, the base station ID of the own station is added and transferred to the uplink, but in the case of the base station apparatuses 2 to 3 having a plurality of lower routes. Waits for delay information from all routes to be collected before transmitting to the upper station.

For example, the base station apparatus 2 sets the delay information 003 (004E4 / 005E5) from the link L2 and the delay information 006E6 from the link L5 to 0,
02 ((003 (004E4 / 005E5)) / 006
E6) is transmitted to the link L1.

By operating in this manner, the headquarters apparatus 1 can obtain delay information and simultaneously recognize the topology (connection state) of all base station apparatuses. In a base apparatus having a plurality of lower routes, IDs and the like can be obtained. Can be controlled so that the information does not collide or overlap.

Here, information transmitted to the head office apparatus 1 and information transmitted through the links L1 to L6 will be summarized and shown.

Headquarters device: 001 ((002 ((003 (0
04E4 / 005E5))) / 006E6) / 007E7) L1: 002 ((003 (004E4 / 005E5)) / 0
06E6) L2: 003 (004E4 / 005E5) L3: 004E4 L4: 007E7 L5: 006E6 L6: 005E5 Also, each base station apparatus i has position information obtained from the GPS receiving means 12 in delay information to be notified to the head office apparatus 1. The head office device 1 can recognize the connection state including the geographical positional relationship by sending the information. Therefore, for example, when the base station device is installed, it can be plotted on a map based on the obtained position information, so that it is easy to confirm the distance between the base stations and the topography around the installation location.

(Embodiment 3) FIG.5 is a block diagram showing a configuration of a base station apparatus for realizing multi-station simultaneous reception. Although the base station device 3 is shown as an example, the other base station devices 2 and 4 to 7 have the same configuration.

The base station device 3 includes a radio transmitting / receiving means 14
A frame synchronization comparing means 17 for synchronizing the timing of an upstream frame from a lower route to which a receiving route from the wireless transmitting / receiving means 14 and a lower station are connected, and a delay time controlled by the frame synchronization comparing device 17. And a route selecting unit 16 for selecting a receiving route from the wireless transmitting / receiving unit 14 and a frame from the lower station and transferring the frame to the upper station.

Next, referring to the explanatory diagram shown in FIG.
A method for adjusting the timing of simultaneous reception of multiple stations in the wireless communication system according to the present embodiment will be described. A1 to A4, B1 to B4, and C1 to C4 shown in the drawing represent the generation timings of the signals at the positions indicated by the same reference numerals in FIG.

First, the downlink frame A1 generated by the head office apparatus 1 and broadcast to each base station apparatus i is delayed by the radio transmission delay means 13 and transmitted from the radio transmission / reception means 14 to the radio signal A.
Sent as 2. Further, the frame A1 passes through the link line and is transmitted to the base station devices 4 and 5, which are lower stations, by the frame B1
Reach as C1.

The frame B 1 arriving at the radio base station 4 is
Delayed by the wireless transmission delay means 13,
Is transmitted as a radio signal B2. The frame C1 arriving at the wireless base station 5 is also delayed by the wireless transmission delay unit 13 and transmitted from the wireless transmission / reception unit 14 as a wireless signal C2. At this time, by setting the delay time of each wireless transmission delay unit 13 of each of the wireless base stations 3 to 5 as described above, the wireless signals A2 to C2 can be simultaneously transmitted in multiple stations.

On the other hand, in a state where multi-station simultaneous transmission is possible, an uplink frame synchronization signal is generated a fixed time after a given downlink frame arrives at the radio transmitting / receiving means 14. If the frame number included in the uplink frame synchronization signal is made to correspond to the frame number included in an arbitrary downstream frame, it can be set identically at each base station.

Next, the frame synchronization comparing means 17 provided in each base station device i compares the upstream frames A3 to C3 arriving from each lower route including those having the same frame number, and The delay time is calculated so that another upstream frame is aligned with the upstream frame of the road.

By setting the delay time calculated for each route in the delay correcting means 18 provided for each route, the upstream frames A4 to A4 passing through the delay correcting means 18 are set.
The position of the frame synchronization signal of C4 becomes coincident.
As for the upstream frames A4 to C4 that have passed, the upstream frame of the route whose priority is determined in advance by the predetermined rule by the route selection means 16 is selected and relayed to the upper station.

By operating in this manner, the delay time of the delay correction means 18 is determined in order from the lowest station, and the timing of the upstream frame is aligned in the base station device where the upstream frame joins. When the setting of one delay correction means 18 is completed, multi-station simultaneous reception is realized.

Further, in a state where multi-station simultaneous reception is possible, the receiving base station may add reception quality information (such as a reception input level or a synchronization word correlation value) to an uplink frame and provide the base station with the reception quality information. The route selection unit 16 may compare the reception quality information included in the uplink frame, select an uplink frame having good reception quality, and relay the frame to the upper station.

For example, the transmission wave of the mobile station device 9 is received by the base station device 5 and the base station device 6 (F2 (9
-5), F2 (9-6)) and F2 (9-16), if the reception quality is better, the base station apparatus 3
Since F2 is not included in the upstream frame from
(9-5) is relayed to the base station apparatus 2 which is an upper station, but the base station apparatus 2 performs F2 (9-6) and F2 (9-5).
The F2 (9-6) is relayed to the head office apparatus 1.

As described above, the route selecting means 16 compares the reception quality information included in the uplink frame, so that when a transmission wave from a certain mobile station device is received simultaneously by a plurality of base station devices, the reception is further improved. Site diversity in which an uplink frame received by a high-quality base station apparatus is automatically selected becomes possible.

As described above, according to the present embodiment, the radio transmission timing of each base station apparatus is set to G on the downlink.
By making corrections with reference to the PS time, multi-station simultaneous transmission becomes possible. In the uplink, the slowest uplink frame is synchronized each time an uplink frame synchronized with the corrected wireless transmission timing merges via the base station apparatus. By being selected after the timing is adjusted, multi-station simultaneous reception becomes possible.

[0060]

As described above, according to the present invention, in each base station apparatus, a value obtained by subtracting the delay time of the own station from the maximum value of the delay information broadcast from the head office apparatus is set as the delay time of the own station. By doing so, the timing adjustment between the base station devices is automated, and the downstream frame transmitted from the head office device is transmitted by radio transmission after being delayed by this delay time, so that all the base station devices transmit at the same time. An object of the present invention is to provide a base station apparatus of a wireless communication system capable of simultaneously transmitting multiple stations.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a wireless communication system to which the present invention is applied;

FIG. 2 is a configuration diagram of a base station apparatus shown in FIG. 1;

FIG. 3 is an explanatory diagram showing a timing adjustment method for simultaneous transmission of multiple stations.

FIG. 4 is a configuration diagram of a wireless communication system that adds its own station ID to delay information and transmits the information to an upper station;

FIG. 5 is a configuration diagram of a base station apparatus shown in FIG. 1;

FIG. 6 is an explanatory diagram showing a timing adjustment method for simultaneous reception of multiple stations.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head office apparatus 2, 3, 4, 5, 6, 7 Base station apparatus 8, 9 Mobile station apparatus 10 GPS satellite apparatus 11 GPS receiving means 12 Radio transmission timing calculation means 13 Radio transmission delay means 14 Radio transmission / reception means 15 Switch means 16 route selection means 17 frame synchronization comparison means 18 delay correction means

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takaaki Fujii 3-1 Tsunashima Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture F-term in Matsushita Communication Industrial Co., Ltd. 5K033 CC01 DA16 DA19 5K042 AA02 CA01 DA15 EA01 FA11 LA13 NA04 5K067 AA23 BB04 CC04 DD17 DD25 EE02 EE10 EE16 EE72 5K072 AA22 BB13 BB18 BB25 CC15 DD20 EE24 FF08

Claims (7)

[Claims] 1. A wireless communication system for transmitting a digital signal in a frame unit of a fixed period between a plurality of base station apparatuses connected to a head office apparatus and a plurality of base station apparatuses in a tree shape, wherein the head office apparatus and the base station apparatus are: Reference signal receiving means for receiving a signal capable of recognizing the same time for all wireless communication systems, wireless transmission timing calculating means, wireless transmission delay means, and wireless transmitting means, wherein the wireless transmission timing calculating means The difference between the reference signal obtained from the reference signal receiving means and the arrival time of the downstream frame transmitted from the head office device is measured and notified to the head office device, and the maximum value of the time difference reported from the head office device is notified. By setting a value obtained by subtracting the measured time difference from the above constant value as the delay time in the transmission delay means, the wireless transmission means can perform multi-station simultaneous transmission. A base station apparatus for a wireless communication system. 2. A radio communication system for transmitting a digital signal in a frame unit of a fixed period between a plurality of base station apparatuses connected to a headquarter station apparatus and a tree, wherein the base station apparatus includes a radio wave from a mobile station apparatus. Wireless receiving means for receiving, a delay correction means for delay-controlling a receiving route from the wireless transmitting / receiving means and an upstream frame from a lower route to which a lower station is connected for each route, and Frame synchronization comparing means for controlling the delay time of the delay correction means in order to synchronize the upstream frame timing, and selecting a frame of each of the routes delayed by the delay correction means and transferring the frame to the upper station. Means, when the transmission wave of the mobile station device is received simultaneously by the plurality of base station devices, the plurality of uplink frames to the base station device with a lower route A base station apparatus for a wireless communication system, wherein multi-station simultaneous reception is performed by adjusting timing at the time of merging. 3. A wireless communication system for transmitting a digital signal in a frame unit of a fixed period between a head office device and a plurality of base station devices connected in a tree-like manner, wherein each of the plurality of base station devices has an arbitrary reference time. And measuring the time difference between the downlink frame arrival time and the base station device without a lower route among the plurality of base station devices, notifies the headquarters device of the measured time difference as delay information, The maximum value of the notified delay information is notified to the plurality of base station devices, and the plurality of base station devices subtract a time difference measured by the own station from the notified maximum value of the delay information. Each of the plurality of base station devices is set as a wireless transmission delay time, and the plurality of base station devices transmit a frame transmitted from the head office device after delaying the wireless transmission delay time by the wireless transmission delay time, thereby simultaneously transmitting multiple stations. The timing adjustment method of a wireless communication system and performing. 4. When the base station device without the lower route notifies the head office device of the delay information, the base station device adds its own base station ID to the delay information and transfers the delay information to an upper route. Upon receiving the base station ID-added delay information from the base station device having no lower route, the base station device having the lower route adds the base station ID of the own station to the delay information and transfers the information to the upper route. The timing adjustment method for a wireless communication system according to claim 3, wherein 5. The plurality of base station apparatuses add position information obtained from a GPS together with the base station ID of the own station to the delay information and transfer the delay information to the head office apparatus. The method according to claim 4, wherein a connection state diagram including a geographical positional relationship is constructed by collating with a connection state diagram. 6. In a wireless communication system for transmitting digital signals in a frame unit of a fixed cycle between a headquarters apparatus and a plurality of base station apparatuses connected in a tree-like manner, a base station apparatus having a lower route is connected to each lower station. Comparing the upstream frame timing and the frame number received by the wireless receiving means of the local station and the local station, and adjusting the delay correcting means provided in each lower path so that the frame timings of the same frame number coincide with each other. A timing adjustment method for a wireless communication system, wherein multi-station simultaneous reception is performed by selecting an upstream frame of a route having a predetermined priority and relaying the frame to an upper station. 7. When comparing an uplink frame from the lower route with a frame received by the radio receiving means of the own station and selecting the same, an uplink frame of a route whose line quality is estimated to be the best is selected as an upper frame. The method according to claim 6, wherein the timing is relayed to a station.