JP2008167500A - Transmission power control method and wireless access system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission power control method where the problem of the conventional control method having imposed a heavy load on a base station device is solved, the base station device transmits a reception level RSSI with respect to a subscriber base station to the subscriber base station and the subscriber base station calculates an optimum transmission power to relieve the load imposed on the base station device and to provide a wireless access system. <P>SOLUTION: This invention provides the transmission power control method and the wireless access system where the base station device 1 measures a reception level from an optional subscriber base station 2 and transmits the result to the subscriber base station 2, the subscriber base station 2 stores in advance an optimum reception level and the transmission power is adjusted depending on a difference between the reception level sent from the base station device 1 and the optimum reception level. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio access system using a subscriber line, and more particularly to a transmission power control method and a radio access system capable of reducing the burden on a base station apparatus side by calculating optimum transmission power on a subscriber base station side.

  A conventional wireless access system includes a subscriber line using wireless called WLL (Wireless Local Loop) or FWA (Fixed Wireless Access). Among these, the one-to-many wireless equipment configured by a wireless transmission path connecting a base station installed by a telecommunications carrier and subscriber (base) stations installed on a plurality of user housing sites is P-MP. This is called the (Point-Multi Point) method.

  The P-MP system uses a high frequency such as a quasi-millimeter wave band and a millimeter wave band, and performs line-of-sight communication using a high gain antenna. This standard is based on the ARIB ( Association of Radio Industries and Business) -standardized by STD59. According to this standard, since the frequency is 22 GHz band / 26 GHz band / 38 GHz band, it is easily affected by weather conditions such as rain and snow, and the C / N value deterioration of the radio line is caused. Stabilization of the line in a subscriber base station is an important issue.

  In particular, in the base station apparatus, since uplink radio signals from a large number of subscriber base stations are received, interference due to channels with other subscriber base stations in the cell, and multipath of own communication While it is necessary to have transmission power that is susceptible to interference and can cope with deterioration of transmission path conditions, control is also required to suppress the transmission power to the minimum necessary to avoid interference.

  Next, a configuration of a conventional radio access system and operations related to uplink transmission power control will be described with reference to FIG. FIG. 6 is a system configuration diagram of a conventional radio access system. As shown in FIG. 6, the conventional radio access system includes a base station apparatus (BSE) 1 ′, a plurality of subscriber base stations (BSE) 2 ′, and a plurality of subscriber stations 3.

  Next, each part which comprises the conventional radio | wireless access system is demonstrated concretely. The base station apparatus (BSE) 1 'performs radio communication with an arbitrary subscriber base station 2'. With regard to uplink transmission power control, an optimum reception level is stored in advance, data received from an arbitrary subscriber base station 2 'is received and a reception level RSSI (Received Signal Strength Indicator) is measured. Then, an optimum transmission power is calculated based on the reception level RSSI and the stored optimum reception level, and a transmission level control instruction for instructing the subscriber base station 2 'to increase or decrease the transmission level is transmitted. It was. Here, the transmission level control instruction may be simply an instruction to increase or decrease the transmission power, or an instruction to increase or decrease the transmission power with a specific numerical value.

  The subscriber base station (CPE) 2 'performs radio communication with the base station apparatus 1'. Regarding uplink transmission power control, when transmitting data to the base station apparatus 1 ', the base station apparatus 1' According to the transmission level control instruction transmitted from 1 ', the transmission level is increased or decreased to keep the optimum transmission level.

  The subscriber station 3 is a terminal device used by a user, is installed on the user's residential land side, is connected to the base station device 1 'via the subscriber base station 2', and performs communication.

  Next, an uplink transmission power control method in a conventional radio access system will be described. In the conventional uplink transmission power control method in the radio access system, when data is transmitted from the subscriber base station 2 ′, the data is received by the base station device 1 ′, and the reception level RSSI is measured at that time, The optimum reception level stored in the base station apparatus 1 ′ is compared with the measured reception level RSSI to determine whether it is optimum. If not optimum, the magnitude relationship between the optimum reception level and the measured reception level RSSI or A transmission level control instruction for commanding increase / decrease of the transmission level is transmitted to the subscriber base station 2 'in accordance with the difference. When a transmission level control instruction is received by the subscriber base station 2 ′, the transmission level is increased or decreased according to the instruction, and data is transmitted to the base station apparatus 1 ′.

  As a prior art of transmission power control related to a radio access system, Japanese Patent Laid-Open No. 5-300066 published in November 12, 1993 “Line-of-sight multi-directional multiple subscriber radio communication system” (Applicant: NEC Corporation, inventor: Yuichiro Bessho). In this conventional technology, the lower station of the relay station in which the failure has occurred performs the antenna direction control and transmission power control function to communicate with the normal upper station, so that the functions of the lower station can be kept normal until the failure is recovered. The service stop time for the subscriber can be minimized.

JP-A-5-300066

  However, in the conventional transmission power control method and radio access system, the base station apparatus determines whether or not the reception level RSSI is optimal for each of a number of subscriber base stations, and if not optimal, sets the optimal transmission level. Since the transmission level control instruction is transmitted to the subscriber base station, particularly when there are many subscriber base stations, there is a problem that the burden on the base station apparatus is large. In particular, in the FWA apparatus, since the data communication speed is extremely high, the CPU power required for processing for data communication is large, and reduction of other processing has been desired.

  The present invention has been made in view of the above circumstances, and the base station device transmits the measurement result of the reception level RSSI to the subscriber base station, and calculates the optimum transmission power on the subscriber base station side. An object of the present invention is to provide a transmission power control method and a radio access system that can reduce the load on the station device side.

  The present invention for solving the problems of the conventional example is a transmission power control method from one subscriber base station device to a base station device among a plurality of subscriber base station devices, wherein the base station device The reception level from the subscriber base station apparatus is measured, the measurement result is converted into a digital value, the digital value is included in the ACK information transmission frame and transmitted to the subscriber base station, and the subscriber base station apparatus Since the optimum reception level in the apparatus is stored in advance, the difference between the measurement result of the reception level transmitted from the base station apparatus and the optimum reception level is obtained, and the transmission power is adjusted according to the difference. The load on the device side can be reduced.

  The present invention for solving the problems of the above conventional example is a radio access system having a base station apparatus and a plurality of subscriber base station apparatuses, wherein the base station apparatus receives from any subscriber base station apparatus. A subscriber base station apparatus comprising: a reception level measuring means for measuring a level; a converting means for converting a measurement result into a digital value; and a transmitting means for transmitting the conversion result in an ACK information transmission frame. Receiving means for receiving the measurement result transmitted from the base station apparatus, and transmission level setting means for calculating transmission level setting data from the measurement result and the optimal reception level stored in advance in the base station apparatus; Since the subscriber base station apparatus has transmission level control means for controlling the transmission level according to the setting data, the load on the base station apparatus side can be reduced.

  According to the present invention, there is provided a transmission power control method from one subscriber base station device to a base station device among a plurality of subscriber base station devices, wherein the base station device receives a reception level from the subscriber base station device. The measurement result is converted into a digital value, the digital value is included in the ACK information transmission frame and transmitted to the subscriber base station, and the subscriber base station device stores in advance the optimum reception level in the base station device. In addition, since it is a transmission power control method for obtaining the difference between the measurement result of the reception level transmitted from the base station apparatus and the optimum reception level and adjusting the transmission power according to the difference, the load on the base station apparatus side There is an effect that can be reduced.

  According to the present invention, there is provided a radio access system having a base station apparatus and a plurality of subscriber base station apparatuses, wherein the base station apparatus measures a reception level from an arbitrary subscriber base station apparatus by a reception level measuring means. The conversion unit converts the measurement result into a digital value, the transmission unit includes the conversion result in an ACK information transmission frame, and the subscriber base station device transmits the measurement result transmitted from the base station device to the reception unit. Radio that receives and calculates transmission level setting data from the measurement result by the transmission level setting means and the optimal reception level stored in advance in the base station apparatus, and controls the transmission level according to the setting data by the transmission level control means Since the access system is used, the load on the base station apparatus side can be reduced.

Embodiments of the present invention will be described with reference to the drawings.
Embodiments of the present invention will be described with reference to the drawings. The function realizing means described below may be any circuit or device as long as it can realize the function, and part or all of the function can be realized by software. is there. Furthermore, the function realizing means may be realized by a plurality of circuits, and the plurality of function realizing means may be realized by a single circuit.

  A transmission power control method and a radio access system according to the present invention are transmission power control from one subscriber base station device to a base station device among a plurality of subscriber base station devices, wherein the base station device is a subscriber. The reception level from the base station apparatus is measured, the measurement result is converted into a digital value, the digital value is included in the ACK information transmission frame and transmitted, and the subscriber base station apparatus determines the optimum reception level in the base station apparatus in advance. Since the difference between the measurement result of the reception level transmitted from the base station device and the optimum reception level is obtained and the transmission power is adjusted according to the difference, the load on the base station device side can be reduced. is there.

  First, the configuration of the radio access system of the present invention and the outline of the uplink transmission power control method will be described with reference to FIG. FIG. 1 is a system configuration diagram of a radio access system according to an embodiment of the present invention. Parts having the same configuration as in FIG. 6 will be described with the same reference numerals. As shown in FIG. 1, the wireless access system according to the present embodiment includes a base station apparatus (BSE) 1, a plurality of subscriber base stations (BSE) 2, and a plurality of subscriber stations 3.

  Next, although each part which comprises the radio | wireless access system of this invention is demonstrated concretely, since the subscriber station 3 is the same as that of the former, description is abbreviate | omitted. The base station apparatus (BSE) 1 performs wireless communication with an arbitrary subscriber base station 2 as in the prior art. However, with respect to uplink transmission power control, as a feature of the present invention, an arbitrary subscriber The reception level RSSI from the base station apparatus 2 is measured, and the measurement result is transmitted to the subscriber base station apparatus 2 as it is. Specifically, the reception level RSSI from an arbitrary subscriber base station 2 is measured, the measurement result is converted into a digital value, and the digital value is included in a downlink frame for performing normal exchange such as ACK information. The data is transmitted to the station 2.

  Here, the format of the downlink frame transmitted from the base station apparatus 1 to the subscriber base station 2 will be described with reference to FIG. FIG. 2 is a format diagram of a downlink frame transmitted from the base station apparatus in the radio access system of the present invention. As shown in FIG. 2, the downlink frame transmitted from the base station apparatus 1 to the subscriber base station 2 has a data part in which data to be transmitted is embedded, and a reception level from the subscriber base station 2 is converted into a hexadecimal by digital conversion. It consists of the RSSI level as a value and ACK information indicating whether or not the received data has been correctly received. There may be no data part. Here, the transmission frame of the data part and the ACK information is conventionally transmitted. In this embodiment, the transmission part of the data part and the ACK information is incorporated in the RSSI level and transmitted, and the RSSI level transmission is performed. Does not send a special frame for.

  The subscriber base station (CPE) 2 performs wireless communication with the base station apparatus 1 as in the conventional case. However, as to the transmission power control of the uplink, as a feature of the present invention, transmission from the base station apparatus 1 is performed. In accordance with the measurement result of the received reception level RSSI, the base station apparatus 1 adjusts the transmission power so that the optimum reception level is obtained. Specifically, the optimal reception level in the base station apparatus 1 is stored in advance, the difference between the measurement result of the reception level RSSI transmitted from the base station apparatus 1 and the optimal reception level is obtained, and according to the difference Data is transmitted to the base station apparatus 1 by adjusting the transmission power.

  Here, the structure of the subscriber base station 2 in the radio | wireless access system of this invention is demonstrated using FIG. FIG. 3 is a configuration block diagram of a subscriber base station in the radio access system of the present invention. As shown in FIG. 3, the subscriber base station (CPE) 2 in the radio access system of the present invention includes an antenna 21, an RF (Radio Frequency) unit 22 having a variable ATT (Attenuator) 23, and an IF (Intermediate Frequency). The control unit 26 includes a unit 24, a base band unit 25, and a control unit 26 having transmission level setting means 27. Here, the antenna 21, the RF unit 22, the IF unit 24, and the baseband unit 25 correspond to the receiving unit in the claims, the transmission level setting unit 27 corresponds to the transmission level setting unit in the claims, and a variable ATT (Attenuator ) 23 corresponds to the transmission level control means in the claims.

  Next, each part which comprises the subscriber base station 2 in the radio | wireless access system of this invention is demonstrated concretely. The antenna 21 performs wireless communication with the base station apparatus 1 and outputs a received wireless signal to the variable ATT 23b and transmits a wireless signal input from the variable ATT 23a.

  The RF unit 22 performs transmission / reception of a radio high-frequency signal and performs frequency conversion between the high-frequency signal and the intermediate frequency signal. And a variable ATT 23b. The variable ATT 23 is an attenuator that attenuates an electric signal, and is a general variable attenuator that can change an attenuation factor according to an input set position. The variable ATT 23a receives a transmission signal from the IF unit 24 as a high-frequency signal. The variable ATT 23b attenuates the received high-frequency signal from the antenna 21 and then converts it to an intermediate frequency.

  The IF unit 24 is a general IF unit that handles an intermediate frequency signal, extracts a baseband signal from the received intermediate frequency signal from the RF unit 22, and converts a transmission baseband signal from the baseband unit 25 into an intermediate frequency. And output to the RF unit 22.

  The baseband unit 25 is a general baseband unit that modulates and demodulates a baseband signal. The baseband unit 25 modulates data input from the control unit 26 into a baseband signal and outputs the baseband signal to the IF unit 24. Data is demodulated from the input baseband signal and output to the control unit 26.

  The control unit 26 controls the conventional subscriber base station 2, and as a characteristic part of the present invention, the optimal reception level in the base station apparatus 1 according to the measurement result transmitted from the base station apparatus 1. The transmission level setting means 27 for setting the transmission power so that

  The transmission level setting means 27 stores the optimal reception level in the base station apparatus 1 in advance, and the reception level (RSSI) received from the base station apparatus 1 and the optimal reception level in the base station apparatus 1 stored in advance. And generating control information for adjusting the transmission power according to the difference.

  Here, the optimum reception level region in the wireless access system of the present invention will be described with reference to FIG. FIG. 4 is an explanatory diagram showing an optimum reception level region in the wireless access system of the present invention. As shown in FIG. 4, the optimum reception level area in the radio access system of the present invention is, for example, when the error-free area is −80 to −40 dBm, the transmission power transmitted from the subscriber base station 2 is error. Since it is important to reduce the interference in the cell by transmitting with a transmission power as small as possible so that no occurrence occurs, it can be said that the optimum reception level is around -70 dBm. Therefore, when data is transmitted from all the subscriber base stations 2 to the base station apparatus 1, in order to adjust the transmission level in the subscriber base station 2 so that the reception level in the base station apparatus 1 is about -70 dBm, The transmission level setting means 27 of each subscriber base station 2 stores -70 dBm as the optimum reception level in advance.

  Next, the flow of the transmission level setting process in the transmission level setting means 27 of the subscriber base station 2 of the wireless access system of the present invention will be described with reference to FIG. FIG. 5 is a flowchart showing the flow of the transmission level setting process in the transmission level setting means of the subscriber base station of the radio access system of the present invention.

  The transmission level setting process in the transmission level setting means of the subscriber base station of the radio access system of the present invention is started every time a downlink frame transmitted from the base station apparatus 1 is received, and the RSSI level is input from the baseband unit 25. (100), for example, the RSSI level input in the variable R is stored (102), and the value obtained by subtracting the variable R from the optimal reception level in the base station apparatus 1 stored in advance is stored in the variable X (104). Level setting data for adjusting the attenuation rate of the variable ATT 23a is generated from the value of the variable X (106), the level setting data is output to the variable ATT 23a (108), and the transmission level setting process is terminated.

  Next, the transmission power control operation in the wireless access system of the present invention will be described with a specific example. In the transmission power control operation in the radio access system of the present invention, for example, −70 dBm is stored in advance as the optimum reception level in the base station apparatus 1 in each subscriber base station 2. When data is transmitted from an arbitrary subscriber base station 2 on the uplink, the reception level (RSSI) is measured by the base station apparatus 1 and the measurement result is converted into a digital value and included in the downlink frame as an RSSI level. And transmitted to the subscriber base station 2. For example, a certain subscriber base station 2 transmits data to the base station apparatus 1 at a transmission level of 0 dBm, and because of rain, snow, etc., line quality degradation occurs, and the RSSI measurement result at the base station apparatus 1 is −80 dBm. If there is, the RSSI level of −80 dBm is transmitted in the downstream frame.

  In the subscriber base station 2, the downlink frame transmitted from the base station apparatus 1 is received by the antenna 21, demodulated via the RF unit 22, IF unit 24, and baseband unit 25 and output to the control unit 26. The transmission level setting means 27 of the control unit 26 receives the RSSI level included in the downlink frame, subtracts the input RSSI level from the optimum reception level in the base station apparatus 1 stored in advance, and varies from that value. Level setting data for adjusting the ATT 23a is generated, the level setting data is output to the variable ATT 23a, and the attenuation rate in the variable ATT 23a is changed to adjust the transmission power.

  Specifically, when the RSSI level −80 dBm is received from the base station apparatus 1, the transmission level setting unit 27 calculates the optimal reception level (−70 dBm) −RSSI level (−80 dBm) = 10 dBm. Accordingly, level setting data for adjusting the attenuation rate of the variable ATT 23a so as to increase the transmission power by 10 dBm is generated and output to the variable ATT 23a. Is to be sent.

  Also, when the line condition is recovered with the transmission power raised, the RSSI measurement result in the base station apparatus 1 becomes larger than −70 dBm, so the calculation is performed based on the RSSI level received in the subscriber base station 2. Control for lowering transmission power is performed.

  According to the transmission power control method in the radio access system of the present invention, the base station apparatus 1 measures the reception level RSSI from any subscriber base station 2 and transmits the measurement result to the subscriber base station 2, In the subscriber base station 2, the optimum reception level in the base station apparatus 1 is stored in advance, the difference between the measurement result of the reception level transmitted from the base station apparatus 1 and the optimum reception level is obtained, and according to the difference Since the transmission power is adjusted and data is transmitted to the base station apparatus 1, the load on the base station apparatus 1 side can be reduced.

  Also, the base station apparatus 1 converts the reception level measurement result from the subscriber base station apparatus 2 into a digital value, and transmits the digital value RSSI level by incorporating it into the downlink frame for transmitting the ACK information. There is an effect that the RSSI level can be transmitted without increasing the transmission load from the base station apparatus 1 to the subscriber base station 2 without generating a frame for level transmission.

  In addition, an optimum reception level in the base station apparatus 1 is preset and stored for each subscriber base station 2, and the difference between the reception level measurement result transmitted from the base station apparatus 1 and the optimum reception level is stored. Accordingly, the transmission power is adjusted and data is transmitted to the base station apparatus 1, so that the optimum reception level can be set for each individual subscriber base station 2 even if the channel quality of the transmission path is different. There is an effect that transmission power control specialized to the line condition can be performed.

  The present invention is suitable for a transmission power control method and a radio access system that can reduce the load on the base station apparatus side.

1 is a system configuration diagram of a radio access system according to an embodiment of the present invention. It is a format figure of the downlink frame transmitted from the base station apparatus in the radio | wireless access system of this invention. It is a block diagram of the configuration of a subscriber base station in the radio access system of the present invention. It is explanatory drawing which shows the area | region of the optimal reception level in the radio | wireless access system of this invention. It is a flowchart figure which shows the flow of the transmission level setting process in the transmission level setting means of the subscriber base station of the radio | wireless access system of this invention. It is a system configuration | structure figure of the conventional radio | wireless access system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1 '... Base station apparatus (BSE) 2, 2' ... Subscriber base station (CPE), 3 ... Subscriber station, 21 ... Antenna, 22 ... RF part, 23a, 23b ... Variable ATT, 24 ... IF , 25 ... baseband unit, 26 ... control unit, 27 ... transmission level setting means

Claims (5)

A transmission power control method from one subscriber base station device to a base station device among a plurality of subscriber base station devices,
The base station apparatus measures a reception level from the subscriber base station apparatus, transmits the measurement result to the subscriber base station apparatus, and the subscriber base station apparatus uses the measurement result in the base station apparatus. A transmission power control method comprising adjusting transmission power so that a reception level is optimal.   The transmission method of the reception level measurement result in the base station apparatus is a method of converting the measurement result into a digital value and transmitting the digital value by including it in an ACK information transmission frame. Transmission power control method.   In the subscriber base station apparatus, a method of adjusting transmission power so that the reception level at the base station apparatus is optimal is stored in advance as the optimal reception level at the base station apparatus and transmitted from the base station apparatus. The transmission power control method according to claim 1 or 2, wherein a difference between a reception level measurement result obtained and the optimum reception level is obtained, and transmission power is adjusted according to the difference. . A radio access system having a base station device and a plurality of subscriber base station devices,
The base station apparatus is a base station apparatus that measures a reception level from an arbitrary subscriber base station apparatus and transmits the measurement result to the subscriber base station apparatus, and the subscriber base station apparatus A radio access system, which is a subscriber base station apparatus that adjusts transmission power so as to obtain an optimum reception level in the base station apparatus according to a measurement result transmitted from a station apparatus.   A radio access system having a base station apparatus and a plurality of subscriber base station apparatuses, wherein the base station apparatus measures a reception level from an arbitrary subscriber base station apparatus, and the measurement result A base station apparatus having conversion means for converting to a digital value and transmission means for transmitting the conversion result included in an ACK information transmission frame, wherein the subscriber base station apparatus is transmitted from the base station apparatus. A reception means for receiving a result; a transmission level setting means for calculating setting data of a transmission level from the measurement result and an optimal reception level stored in advance in the base station apparatus; and a transmission level according to the setting data. A radio access system comprising a subscriber base station device having transmission level control means for controlling.

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