JP2004336419A - P-mp system, base station, and subscriber station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a P-MP system having high-speed followup ability and stable automatic gain control (AGC) even when no user traffic is available. <P>SOLUTION: In the P-MP system, a base station comprises: a low-speed polling means conducting polling using a significant signal for controlling subscriber station monitoring at a specified first cycle; a high-speed polling means conducting the polling using a nonsignificant signal at a second cycle higher than the first cycle while no polling using the significant signal is conducted: and an automatic gain control means applying the automatic gain control to the radio signal of a subscriber station by using a signal returned from the subscriber station at the polling by the high-speed polling means, and the subscriber station is provided with a means for identifying whether the received radio signal is the nonsignificant signal or the significant signal, returning the received radio signal as received to the base station when the received radio signal is the nonsignificant signal, and conducting control complying with the significant signal when the received radio signal is the significant signal. Thus, the system has the high-speed followup ability without causing an adverse effect on the monitoring control for the subscriber station, stably conducts the automatic gain control (AGC) even when no user traffic is available, and conducts efficient monitoring control for the subscriber station. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Field of the Invention]
The present invention relates to a fixed wireless access (FWA) system for connecting a base station and a subscriber station by fixed wireless, and more particularly, to a P-MP (Point To MultiPoint) system, which is one of the FWA systems. .
[0002]
[Prior art]
The P-MP system is a communication system in which one base station and a plurality of subscriber stations are connected by fixed radio (see Non-Patent Document 1).
In this P-MP system, the base station polls these subscriber stations in one cycle in order to monitor and control the subscriber stations.
[0003]
FIG. 7 is a diagram illustrating a conventional polling operation performed for monitoring and controlling a subscriber station in a P-MP system, and FIG. 8 is a diagram illustrating a conventional base station control circuit.
As shown in FIG. 7, in the conventional polling of the monitoring and control of the subscriber station, at the time interval T1 (T1> wireless frame interval), each subscriber station (subscriber station # 1 to subscriber # 1) joins from the base station (FIG. 8). Station #X).
The conventional polling operation is performed by software at the base station and the subscriber station.
[0004]
By the way, in this P-MP system, when wireless communication is performed using a TDMA (Time Division Multiple Access) / TDD (Time Division Duplex) method, wireless signals transmitted from a plurality of subscriber stations are burst at a base station. (Ie, at different times).
[0005]
The base station extracts digital data from the burst-received radio signal by the following method. That is, the received modulated signal is amplified by an amplifier, converted from an RF (Radio Frequency) band to an IF (Intermediate Frequency) band, and then a modulated signal in the IF band is detected to extract a baseband signal. In this method, the baseband signal is A / D converted by a / D converter to determine the level of each baseband symbol.
[0006]
For the extraction of such digital data, the following two requests are usually made to the base station.
The first requirement is a requirement to keep the amplitude level of the received modulated signal at an appropriate level. This requirement is made to ensure that the amplifier does not saturate during amplification of the received modulated signal.
The second requirement is to adjust the baseband signal level input to the AD converter to an appropriate level. This request is made because the signal level that can be converted by the AD converter has a set range, and the effect of quantization noise during AD conversion is reduced.
[0007]
In order to satisfy the first requirement, it is necessary for the base station to perform automatic gain control (AGC: Auto Gain Control) on the amplitude level of the modulated signal from each subscriber station. This is because the installation conditions of each subscriber station are different, so that the amplitude levels of the radio signals from a plurality of subscriber stations received in a burst at the base station are usually different for each subscriber.
[0008]
Then, in order to perform the automatic gain control well, the amplitude level of the signal from the subscriber station is sampled at fixed time intervals to calculate a moving average of the maximum value, and the calculated moving average is set in advance. It is necessary to perform gain adjustment based on the difference from the standard reception power level. This is because in the FWA system, although the propagation path environment is relatively stable as compared with the mobile radio system, an excessive interference wave other than the desired wave may be input.
[0009]
In addition, in order to stably perform the automatic gain control, it is necessary to receive radio signals from all the subscriber stations within a predetermined time even when there is no user traffic.
Furthermore, in order to improve the high-speed tracking accuracy of the automatic gain control, it is necessary to shorten the sampling time and receive radio signals from all the subscriber stations in a short time and at a high speed.
[0010]
On the other hand, as means for satisfying the second requirement, a gain adjustment signal is prepared in a preamble signal provided before a modulation signal modulated by digital data, and the base station receives the gain adjustment signal. After performing A / D conversion, the signal level is detected, the gain of the gain adjustment signal is adjusted so that the detected value becomes an appropriate level, and the baseband signal level received thereafter is always adjusted to the appropriate level. Means for automatic gain adjustment (AGC) can be considered.
[0011]
However, if the detection of the signal level using the gain adjustment signal and the control for adjusting the gain adjustment to an appropriate level are repeatedly performed each time a radio signal from each subscriber is received, the gain adjustment is performed for each burst. In this case, the gain adjustment signal in the preamble signal must be lengthened, and the frame efficiency deteriorates.
[0012]
Therefore, as means for satisfying the second requirement, apart from a user data frame for transmitting user data traffic, a DMF for monitoring and controlling a subscriber station and adjusting a propagation delay amount in a radio frame is used. It is effective to provide a frame (Dray Management Frame) and use a gain adjustment signal in the preamble signal of the DMF frame to control all the subscriber stations to make a round at a fixed interval.
[0013]
Conventionally, the above two automatic gain adjustments are performed in one cycle by the polling for monitoring and controlling the subscriber station shown in FIG.
[0014]
[Non-patent document 1]
Edited by Takeshi Hattori and Masanobu Fujioka, "IDG Information and Communication Series Wireless Broadband Textbook", First Edition, IDG Japan Inc., June 10, 2002, p. 313-316
[0015]
[Problems to be solved by the invention]
However, the desired polling cycle differs depending on the purpose of the polling (for example, monitoring control of a subscriber station, gain adjustment, adjustment of transmission delay amount, etc.).
[0016]
For example, when supervising and controlling a subscriber station, polling having a relatively slow cycle and aperiodicity is desirable in consideration of the processing capacity of the control unit and the like. When performing the adjustment and the propagation delay amount adjustment, high-speed polling is desired to be able to follow the ever-changing propagation path change.
[0017]
For this reason, in the conventional means for performing the automatic gain adjustment (AGC) in one cycle by the polling for monitoring and controlling the subscriber station in FIG. 7 described above, the automatic gain adjustment is performed at high speed propagation path change such as rainfall. There was a problem that it was not possible to follow.
[0018]
In view of such circumstances, the present invention performs polling control that requires high speed by hardware, performs polling control that requires low speed by software, and is not affected by the monitoring control of the subscriber station. It is an object of the present invention to provide a P-MP system capable of following at high speed and stably performing automatic gain adjustment (AGC) even when there is no user traffic.
[0019]
[Means for Solving the Problems]
According to the present invention, the above-mentioned problem is solved by the following means.
[0020]
According to a first invention, in a P-MP system in which one base station and a plurality of subscriber stations are connected by fixed radio, the base station transmits the plurality of subscribers at a predetermined first cycle. Low-speed polling means for polling stations using a significant signal for subscriber station monitoring and control; and faster than the first period while no polling using the significant signal is performed. In a second period, high-speed polling means for polling each of the plurality of subscriber stations using an invalid signal, and signals respectively returned from the plurality of subscriber stations in the polling by the high-speed polling means. Automatic gain adjustment means for automatically adjusting the gain of each of the signals transmitted from the plurality of subscriber stations, respectively, wherein the plurality of subscriber stations each Identify whether the signal transmitted from the ground station is the insignificant signal or the significant signal, and if the insignificant signal, return the insignificant signal to the base station as it is to be the significant signal. In some cases, the P-MP system includes means for performing control according to the significant signal.
[0021]
According to a second aspect, in the P-MP system according to the first aspect, the base station further sends a significant signal for monitoring the subscriber station to each of the plurality of subscriber stations in an aperiodic manner. A P-MP system comprising an aperiodic polling means for performing polling using the P-MP system.
[0022]
According to a third aspect of the present invention, in a base station connected to a plurality of subscriber stations by fixed radio, a significant number of subscriber station monitoring control signals are provided to the plurality of subscriber stations at a predetermined first cycle. Low-speed polling means for performing polling using a significant signal; and while the polling using the significant signal is not performed, the plurality of subscriber stations are provided with a second cycle faster than the first cycle. High-speed polling means for performing polling using an unnecessary signal, and signals transmitted from the plurality of subscriber stations in the polling by the high-speed polling means. Automatic gain adjustment means for automatically adjusting the gain of each signal.
[0023]
A fourth invention is the base station according to the third invention, further comprising an aperiodic non-periodic polling of the plurality of subscriber stations using a significant signal for subscriber station monitoring control. A base station comprising polling means.
[0024]
According to a fifth aspect of the present invention, in a subscriber station of a P-MP system connected to one base station by fixed radio, a signal transmitted from the base station is an unnecessary signal or a significant signal for monitoring and controlling the subscriber station. A means for performing the control according to the significant signal if the signal is a significant signal, and if the signal is the insignificant signal, the unnecessary signal is returned to the base station as it is, and if the signal is the significant signal, the signal is controlled. Is a subscriber station.
[0025]
Embodiment of the present invention
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
In the P-MP system according to the embodiment of the present invention, monitoring and control of a subscriber station, adjustment of a propagation delay amount, and gain adjustment are performed separately from a user data frame for transmitting unpredictable data traffic. (Dray Management Frequency) is prepared, and a signal for gain adjustment is prepared in the preamble signal of the DMF frame.
[0026]
Further, a TDMA control circuit for dividing and synthesizing a TDMA signal for each determined radio frame period is provided, and a gain adjustment counter indicating a subscriber station for adjusting a propagation delay amount and a gain is provided in the TDMA control circuit.
Then, an unnecessary command signal (empty) is transmitted to the subscriber station indicated by the value in the gain adjustment counter for each radio frame, and the gain adjustment counter value is decremented.
In the gain adjustment counter, a value indicating the maximum number of subscriber stations is set as an initial value. When the value becomes 0, the maximum number of subscriber stations is set.
In addition, ALL “0” data is inserted in the unnecessary command signal (empty).
[0027]
Next, in the TDMA control circuit, a command FIFO for receiving a significant command signal for monitoring and controlling the subscriber station, a command write flag indicating that the command signal has been written, And a monitoring counter indicating the remote station.
When the command write flag is invalid, the TDMA control circuit performs high-speed polling control using the gain adjustment counter. On the other hand, when the command write flag is present, the monitoring counter monitors the command signal input to the command FIFO. Send to the indicated subscriber station.
Here, significant command data for instructing the subscriber station is inserted in the significant command signal (significant signal).
[0028]
Next, in the subscriber station that has received the command signal, an unnecessary command signal (empty) for performing gain adjustment and a significant command signal for instructing monitoring control of the subscriber station are identified, and the command signal ( In the case of (vacant), a response (vacant) is returned to the base station as it is.
Therefore, the base station can perform automatic gain adjustment of the radio signal and the baseband signal for each subscriber station by using the response signal and the gain adjustment signal in the preamble signal included in the response signal.
[0029]
When the subscriber station receives a significant command signal (significant signal), the subscriber station transmits the signal to the response FIFO. Then, the supervisory control circuit of the subscriber station performs control according to the instruction from the base station and edits the response signal internally.
[0030]
The monitoring control circuit of the base station performs low-speed polling control even for an aperiodic monitoring control command without being affected by high-speed polling control for performing automatic gain control.
[0031]
Then, the monitoring control circuit of the base station includes means for limiting the number of transmissions of a significant command signal, and transmits a command request and a response request at intervals in consideration of a response signal editing time and the like.
[0032]
Further, the monitoring control circuit of the subscriber station that has received the response request transmits the previously edited response signal to the base station via the response FIFO.
[0033]
In addition, the base station that has received the response signal discriminates between an unnecessary response signal (empty) and a significant response signal, discards the data if the response signal is unnecessary (empty), and discards the data if the response signal is significant. A response signal is transmitted to the monitoring control circuit via the response FIFO.
[0034]
As described above, according to the P-MP system according to the embodiment of the present invention, high-speed polling control and arbitration of aperiodic and low-speed polling control are possible, and are affected by user data traffic and supervisory control traffic. Therefore, it is possible to perform automatic gain control that is stable and capable of following at high speed. In addition, an inexpensive control unit can realize monitoring control that occurs aperiodically, and can perform efficient monitoring control of a subscriber station without affecting automatic gain control.
[0035]
【Example】
FIG. 2 is a diagram illustrating an overall configuration of the P-MP system according to the embodiment of the present invention.
This P-MP system is a system for providing a fixed wireless access service (FWA service) to a plurality of subscribers, and includes a base station 11 and a plurality of subscriber stations (21 (1) to 21 (3)). ) Are connected by fixed wireless communication.
The base station 11 is also connected to a network, and the plurality of subscriber stations (21 (1) to 21 (3)) are also connected to terminals (not shown) such as personal computers.
[0036]
In this P-MP system, a terminal (not shown) connected to the subscriber station and a network can be connected via fixed wireless communication, so that the terminal (not shown) is connected to the terminal as if it were wired. It is possible to provide various IP services.
Further, by allowing the base station and a plurality of subscriber stations to perform bidirectional communication based on the TDMA / TDD system and allocating a common radio frequency (for example, a frequency in a 26 GHz band), efficient communication becomes possible.
[0037]
FIG. 3 is a diagram showing a configuration example of a TDMA / TDD radio frame transmitted and received by a base station and a plurality of subscriber stations in the P-MP system of FIG.
The period of the radio frame is determined by conditions such as hardware. In the embodiment, the period of the radio frame is set to 1 ms for convenience of explanation.
[0038]
As shown in FIG. 3, this radio frame includes an uplink, a downlink, and a guard time. The uplink is composed of TS11 and TS12, the downlink is composed of TS13, TS14 and TS15, and the guard time is composed of TS16.
[0039]
The TS11 (Time Slot 11) in FIG. 3 is an area that can be accessed by all subscriber stations, and includes a frame structure area including frame structure information, and a supervisory control area (command) including a MAC ID and a command that is an instruction for the subscriber station. ), A slot demand arbitration area for arbitrating access to the TS 14 (Time Slot 14), and an uplink data allocation area indicating the position of the uplink data area for transmitting uplink data and the number of time slots.
[0040]
TS12 (Time Slot 12) is a downlink data area for transmitting downlink user data from the base station 11 to a plurality of subscriber stations (21 (1) to 21 (3)).
[0041]
The TS 13 (Time Slot 13) measures a propagation delay time caused by a distance difference between the base station 11 and a plurality of subscriber stations (21 (1) to 21 (3)), and measures each propagation delay time of each subscriber station (21 ( This is a DMF area for adjusting the transmission timing from 1) to 21 (3)).
[0042]
The DMF area includes an area for controlling a radio signal transmitted from each of the subscriber stations (21 (1) to 21 (3)) in a burst manner so as not to collide with the base station 11, and a DMF frame. Have been.
[0043]
The DMF frame includes a preamble signal for establishing frame synchronization, a MAC ID indicating a subscriber station to which a response is returned, a response (uplink monitoring signal), and a guard time (GT). A gain adjustment signal for performing gain adjustment is arranged in the preamble signal of the DMF frame, and gain adjustment is performed for all uplinks using the gain adjustment signal.
[0044]
The TS 14 (Time Slot 14) is an area for making an uplink data request randomly generated in each of the subscriber stations (21 (1) to 21 (3)), and is accessible according to an instruction in the slot demand arbitration area.
[0045]
TS15 (Time Slot 15) is an area for transmitting uplink user data from a plurality of subscriber stations (21 (1) to 21 (3)) to the base station 11.
[0046]
TS16 (Time Slot 16) is set at the boundary between the uplink and the downlink, and is a guard time for preventing interference.
[0047]
FIG. 1 is a diagram illustrating a polling control operation in a P-MP system according to an embodiment of the present invention.
[0048]
As shown in FIG. 1, the hardware of the base station (base station (hardware)) performs high-speed polling. That is, the base station (hardware) transmits an unnecessary command signal (vacant) to all the subscriber stations in the radio frame period T0 (for example, 1 ms), and transmits the unnecessary command signal (vacant) to the transmitted unnecessary command signal (vacant). To receive an unnecessary response signal (empty) which is repeatedly transmitted from the subscriber station.
[0049]
Then, the base station (hardware) uses the received unnecessary response signal (empty) and the gain adjustment signal included in the preamble signal of the unnecessary response signal to automatically adjust the radio signal and the baseband signal, respectively. Adjustment (AGC) is performed.
[0050]
On the other hand, base station software (base station (software)) performs low-speed polling. That is, the base station (software) transmits a significant command signal (command instruction or response request) to all the subscriber stations at a period (T1 / 2) slower than T0, and this significant signal is transmitted. The supervisory control of the subscriber station is performed using the command signal.
[0051]
The number of transmissions of the command signal is limited by setting the low-speed polling period (T1) to, for example, 10 ms so as not to affect the automatic gain adjustment (AGC) by the high-speed polling.
[0052]
FIG. 4 is a diagram illustrating a circuit structure of the base station 11 included in the P-MP system according to the embodiment of the present invention.
As shown in FIG. 4, the base station 11 includes an antenna 12, a high-frequency circuit 32, and a communication line control circuit 33.
[0053]
The high-frequency circuit 32 includes a receiver 41, a transmitter 42, and a switch 43.
[0054]
The communication control circuit 33 includes a modulation / demodulation circuit 51, a TDMA control circuit 52, a MAC (media access control) control circuit 53, an LLC (logical link control) control circuit 54, a communication interface circuit 55, a scheduling circuit 56, and a monitoring control circuit 57. Is provided.
[0055]
The communication interface circuit 55 is connected to a network (FIG. 7) such as an IP network.
[0056]
The LLC layer control circuit 54 has a built-in buffer for temporarily storing data of a transmission signal and a reception signal. The LLC layer control circuit 54 distributes a signal received from the communication interface circuit 55 to a corresponding subscriber station, generates a wireless packet, and the like.
[0057]
The MAC layer control circuit 53 assigns a device identification ID (MACID) at the layer 2 level to the data, and dynamically and efficiently allocates time slots (bands) of the uplink / downlink data area using the scheduling circuit 57.
[0058]
The TDMA control circuit 52 is a circuit for generating the radio frame configuration shown in FIG.
[0059]
The monitoring control circuit 56 is a circuit for monitoring and controlling the subscriber station.
[0060]
The modulation / demodulation circuit 51 modulates a baseband signal input from the TDMA control circuit 52 and outputs the modulated signal to the high frequency circuit 32, and demodulates an intermediate frequency (IF band) received signal input from the high frequency circuit 32 and modulates the MAC layer. Output to the control circuit 52.
[0061]
The transmitter 42 of the high frequency circuit 32 converts the frequency of the intermediate frequency (IF band) signal input from the modulation / demodulation circuit 51 into a radio frequency (RF band), and converts the frequency-converted radio frequency (RF band) high frequency signal. The power is amplified and output to the antenna 12 via the switch 43.
[0062]
The receiver 41 of the high frequency circuit 32 receives a radio frequency (RF band) reception signal received by the antenna 12 via a switch 43, and amplifies the input reception signal by a built-in low noise amplifier. After that, the frequency is converted to an intermediate frequency (IF band) and output to the modulation / demodulation circuit 51.
[0063]
The base station 11 implements the above-described high-speed polling and low-speed polling using the modulation / demodulation circuit 51, the TDMA control circuit 52, and the monitoring control circuit 56.
In this specification, the modulation / demodulation circuit 51, the TDMA control circuit 52, and the monitoring control circuit 56 are referred to as a polling control circuit.
[0064]
FIG. 5 is a diagram illustrating in detail the polling control circuit (the modulation / demodulation circuit 51, the TDMA control circuit 52, and the monitoring control circuit 56 in FIG. 4).
[0065]
When the command write end flag stored in the FIFO buffer SR is no writing (= 0), the TDMA control circuit 52 does not encrypt the unnecessary command signal (empty) by the encryption circuit, The phase is adjusted, an error correction code is added, a radio frame is formed, and the formed radio frame is transmitted to the subscriber station indicated by the gain adjustment counter via the modulation / demodulation circuit 51.
[0066]
The unnecessary command signal (empty) may be a signal that can be identified as a significant command for monitoring and control. For example, a signal that sets all command data to “0” (empty burst) can be considered.
[0067]
The gain adjustment counter is a counter that indicates the subscriber station that performs the adjustment of the propagation delay amount and the gain adjustment, and a value that indicates the maximum number of subscriber stations is set as an initial value. The TDMA control circuit 52 decrements the value of the gain adjustment counter each time an unnecessary command signal (empty) is transmitted, and when the gain adjustment counter becomes 0, sets the maximum number of subscriber stations again.
[0068]
The TDMA control circuit 52 outputs, to the AGC circuit of the modem 51, the EID number held in the EID holding register, which is the value coincident with the number of the subscriber station that transmitted the unnecessary command signal. From this EID number, the AGC circuit can know from which subscriber station the DMF frame is received.
[0069]
The supervisory control circuit 56 is controlled by software, and issues a command signal (significant signal) for performing supervisory control of the subscriber station at a slow period (T1 / 2) without affecting the automatic gain adjustment. The command is stored in the FIFO, the command write end flag of the FIFO buffer SR is set to “write” (= 1), and the subscriber station number indicating the subscriber station that performs monitoring control is stored in the monitoring counter.
[0070]
When the command write end flag is set to write (= 1), the TDMA control circuit encrypts a significant command signal (significant signal) stored in the command FIFO by the encryption circuit, and the TDMA control circuit encrypts the significant command signal by the phase adjustment circuit. The phase is adjusted, an error correction code is added, the output is output to the modulation / demodulation circuit 51, and transmitted to the subscriber station indicated by the subscriber station number stored in the monitoring counter.
[0071]
The AGC circuit of the modulation and demodulation circuit 51 obtains an AGC control value from the response signal transmitted from the subscriber station and the gain adjustment signal included in the preamble signal of the response signal, and obtains the AGC control value for each EID number. Store in memory.
[0072]
The AGC control circuit performs gain control based on the AGC control value stored in the internal memory when receiving user data from the subscriber station, and receives the burst data from the plurality of subscriber stations. Before the radio signals having different amplitude levels are input to the AD converter, the signals are controlled so as to have an appropriate level.
[0073]
The TDMA control circuit 52 corrects the error of the response signal output from the AGC circuit, adjusts the phase, and identifies the response signal. Discard. On the other hand, when the data is other than ALL “0”, the data is decoded as a significant response signal (significant signal) and output to the monitoring control circuit via the response FIFO.
[0074]
FIG. 6 is a diagram illustrating a polling control circuit in a subscriber station of the P-MP system according to the embodiment of the present invention.
[0075]
The TDMA circuit identifies whether the command is an empty burst for gain adjustment or a significant command by examining the data contents. When the burst is ALL “0”, the response (ALL “0”) is transmitted in the DMF frame. )). If the command is a significant command other than ALL “0”, a response is input to the command FIFO and output to the monitoring control circuit.
The supervisory control circuit to which the significant command signal has been input performs control according to the command instruction from the base station, edits the response signal, and stores it inside.
[0076]
Then, the monitoring control circuit of the subscriber station stores the previously edited response signal in the response FIFO according to the response request from the base station, sets a command write end flag to (= 1), and sets the TDMA control. A response signal is transmitted to the base station according to the uplink transmission timing of the circuit.
[0077]
As described above, according to the P-MP system according to the embodiment of the present invention, it is possible to perform polling control to make a round at intervals of the radio frame period × the maximum number of subscriber stations, and to set the radio frame period to 1 ms, When the maximum number of subscriber stations is set to 100 stations, high-speed and stable automatic gain control with a period of 100 ms can be performed without being affected by user data traffic and supervisory control traffic.
[0078]
Further, according to the P-MP system according to the embodiment of the present invention, the supervision and control of the subscriber station which occurs aperiodically can be realized by the inexpensive control unit, and the efficient subscription can be performed without affecting the automatic gain control. Remote station monitoring control is possible.
[0079]
【The invention's effect】
As described above, according to the present invention, high-speed polling can be performed for automatic gain control that needs to quickly follow a change in a propagation path such as rainfall, while monitoring a subscriber station. For control, low-speed polling can be performed.
Therefore, according to the present invention, automatic gain adjustment (AGC) can be performed stably at a high speed without being affected by the monitoring control of the subscriber station and even when there is no user traffic. In addition, efficient monitoring and control of subscriber stations can be performed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a polling control operation in a P-MP system according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an overall configuration of a P-MP system according to an embodiment of the present invention.
3 is a diagram illustrating a configuration example of a TDMA / TDD radio frame transmitted and received by a base station and a plurality of subscriber stations in the P-MP system of FIG. 2;
FIG. 4 is a diagram illustrating a circuit structure of a base station 11 included in a P-MP system according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating in detail a polling control circuit (the modulation / demodulation circuit 51, the TDMA control circuit 52, and the monitoring control circuit 56 in FIG. 4).
FIG. 6 is a diagram illustrating a polling control circuit in a subscriber station of the P-MP system according to the embodiment of the present invention.
FIG. 7 is a diagram showing a conventional polling operation performed for monitoring and controlling a subscriber station in a P-MP system.
FIG. 8 is a diagram showing a conventional base station control circuit.
[Explanation of symbols]
11 base stations
12 Antenna
21 (1), 21 (2), 21 (3) Subscriber station
22 (1), 22 (1), 22 (1) Antenna
32 high frequency circuit
33 Communication control circuit
41 Receiver
42 transmitter
43 switch
51 Modulation / demodulation circuit
52 TDMA control circuit
53 MAC layer control circuit
54 LLC Layer Control Circuit
55 Communication Interface Circuit
56 Monitoring and control circuit
57 Scheduling Circuit

Claims (5)

In a P-MP system in which one base station and a plurality of subscriber stations are connected by fixed radio,
The base station comprises:
Low-speed polling means for polling each of the plurality of subscriber stations using a significant signal for subscriber station monitoring and control at a predetermined first cycle;
While polling using the significant signal is not being performed, high-speed polling is performed on each of the plurality of subscriber stations using an invalid signal in a second cycle that is faster than the first cycle. Polling means;
Using a signal returned from each of the plurality of subscriber stations in the polling by the high-speed polling means, automatic gain adjustment means for automatically adjusting the gain of each signal transmitted from each of the plurality of subscriber stations,
With
Each of the plurality of subscriber stations identifies whether the signal transmitted from the base station is the insignificant signal or the significant signal, and if the signal is the insignificant signal, transmits the ineffective signal to the base station as it is. Means for returning to a station and performing control according to the significant signal when the signal is the significant signal,
A P-MP system, characterized in that: 2. The P-MP system according to claim 1, wherein the base station further non-periodically polls the plurality of subscriber stations using a significant signal for subscriber station monitoring control. A P-MP system comprising periodic polling means. In a base station connected to a plurality of subscriber stations by fixed radio,
Low-speed polling means for polling each of the plurality of subscriber stations using a significant signal for subscriber station monitoring and control at a predetermined first cycle;
While polling using the significant signal is not being performed, high-speed polling is performed on each of the plurality of subscriber stations using an invalid signal in a second cycle that is faster than the first cycle. Polling means;
In the polling by the high-speed polling means, using a signal returned from each of the plurality of subscriber stations, automatic gain adjustment means for automatically adjusting the gain of each signal transmitted from each of the plurality of subscriber stations,
A base station comprising: 4. The base station according to claim 3, further comprising: an aperiodic polling means for aperiodically polling the plurality of subscriber stations using a significant signal for monitoring and controlling the subscriber stations. Base station to be characterized. In a subscriber station of a P-MP system connected to one base station by fixed radio, identifying whether a signal transmitted from the base station is an unnecessary signal or a significant signal for subscriber station monitoring control, A subscriber that, if the signal is an ineffective signal, returns the ineffective signal to the base station as it is, and if the signal is a significant signal, performs control according to the significant signal. Bureau.

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