KR100701765B1 - Method of open loop power control of B-WLL repeater - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an open circuit type power control method in a broadband wireless subscriber network repeater.

2. The technical problem to be solved by the invention

According to the present invention, a repeater located between a base station and a subscriber device adjusts its own transmission power according to the reception power level, thereby preventing the interference between adjacent cells or adjacent channels due to unnecessary excessive transmission power and transmitting a signal having an appropriate power even in a rain. The purpose of the present invention is to provide a computer-readable recording medium recording an open circuit type power control method in a broadband wireless subscriber network repeater and a program for realizing the same.

3. Summary of the Solution of the Invention

The present invention provides a method for controlling transmission power (downward power) from a broadband wireless subscriber network (B-WLL) repeater to a subscriber device, the method comprising: a downlink signal receiving step of receiving the downlink signal from the base station; And a power control step of transmitting, by the repeater, the transmission power of the received downlink signal to the subscriber device according to the signal power level received from the base station.

4. Important uses of the invention

The present invention is used for power control in broadband wireless subscriber network.

Broadband Wireless Subscriber Network, Repeater, Power Control, Open Circuit Power Control

Description

Open-circuit power control method in broadband wireless subscriber network repeater {Method of open loop power control of B-WLL repeater}             

1 is an explanatory diagram of a power control method between a base station and a repeater according to the present invention;

2 is an explanatory diagram of a power control method between a repeater and a subscriber device according to the present invention;

3 is an explanatory diagram of dynamic range characteristics of an automatic gain controller (AGC) of a repeater to which the present invention is applied.

4 is an explanatory diagram of a receiver signal level of a repeater to which the present invention is applied;

5 is a block diagram of an automatic gain controller AGC of a repeater to which the present invention is applied.

6 is an explanatory diagram of a power control method in a broadband wireless subscriber network according to the present invention;

The present invention relates to a power control method in a broadband wireless subscriber network, and more particularly, an open circuit scheme in a broadband wireless subscriber network repeater, in which a repeater located between a base station and a subscriber device adjusts its own transmission power according to a level of received power. A computer-readable recording medium having recorded thereon a power control method and a program for realizing the same.

Power control in the B-WLL is to control the transmission power between the base station and the subscriber station. Although it is possible to transmit / receive even with a small transmission power on a clear day, when the rain falls a lot, the power received is reduced due to the effect of rainfall, so it is necessary to increase the transmission power.

As described above, controlling the transmission power due to a weather condition or for some reason is power control, and the purpose of the power control is to provide high quality communication service and to minimize radio interference between adjacent cells with an appropriate transmission output.

B-WLL is not a power control for mobile stations and base stations, which is a fixed-to-mobile form of CDMA, but because it is a fixed-to-fixed connection between subscribers and base stations, it is affected by rainfall attenuation. It is slightly different from power control of communication.

Therefore, in the design of the link in the B-WLL system, the output per hour propagates as far as the margin in the rain, causing the same interference to other cells using the same frequency.

The present invention has been made to solve the above problems, the repeater located between the base station and the subscriber device adjusts its own transmission power according to the level of the received power, the adjacent cell or adjacent channel due to unnecessary excessive transmission power The purpose of the present invention is to provide an open circuit type power control method of a broadband wireless subscriber network repeater that can transmit a signal of an appropriate power even in case of rain and to prevent interference between the computers and a computer readable recording medium recording a program for realizing the same. have.

In order to achieve the above object, the present invention provides a method for controlling transmission power (downward power) from a broadband wireless subscriber network (B-WLL) repeater to a subscriber device, wherein the repeater receives a downlink signal from a base station. Receiving step; And a power control step of transmitting, by the repeater, the transmission power of the received downlink signal to the subscriber device according to the signal power level received from the base station.

In addition, the present invention provides a power control method in a broadband wireless subscriber network (B-WLL) repeater, wherein the repeater receives an uplink signal from a subscriber device and is received according to the signal power level received from the base station. An uplink power control step of adjusting a transmit power of an uplink signal and transmitting the uplink signal to the base station; And a downlink power control step of receiving, by the repeater, the downlink signal from the base station, adjusting the transmission power of the received downlink signal according to the signal power level received from the base station, and transmitting the downlink signal to the subscriber station.

In addition, the present invention, in the broadband wireless subscriber network (B-WLL) repeater having a processor to control the transmission power (downward power) to the subscriber device, the downlink signal for receiving the downlink signal from the base station the repeater Receiving function; And a computer-readable recording medium having recorded thereon a program for realizing a power control function of adjusting the transmission power of the received downlink signal according to the signal power level received from the base station and transmitting the received downlink signal to the subscriber device. do.

In addition, the present invention, in the open-circuit power control, to the B-WLL repeater having a processor, the repeater receives the upstream signal from the subscriber device, the signal received from the base station An uplink power control function for adjusting a transmission power of the received uplink signal according to a power level and transmitting the same to the base station; And a repeater receives the downlink signal from the base station, adjusts the transmission power of the received downlink signal according to the signal power level received from the base station, and transmits the downlink power control function to the subscriber device. Provide a computer readable recording medium having recorded thereon.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an explanatory diagram of a power control method between a base station and a repeater according to the present invention.

In the case of using a repeater, the repeater should receive the transmission signal from the base station and transmit it to the subscriber device. In addition, the repeater should receive the signal transmitted from the subscriber station and transmit the signal back to the base station. Due to the role of the repeater, power control should be performed between the base station and the repeater, and the repeater and the subscriber device.

First, power control between the "base station" and "relay" will be described.

The power control targets of the base station and the relay period include (1) "downstream base station transmission output" and (2) "upstream repeater transmission output".

First, referring to the "downstream base station transmission output", the transmission (downward) power control from the base station to the repeater applies a closed loop control method. Because the base station power is controlled by the edge subscriber of the cell that already has a line of sight, the repeater does not need to control the base station.

Here, the closed-loop control method is as follows. The signal transmitted from the base station is received by the receiver of the subscriber device at the edge of the cell and the received power is measured. The measured power is sent to the base station via the transmitter via the transmitter to the power control information that is compared with the reference value already set in the uplink subscriber.

The signal received from the base station extracts the demodulator power control information to vary and control the ultra-short amplifier of the base station transmitter, thereby automatically increasing or decreasing the output of the transmitter.

That is, in brief, the transmission power of the base station is controlled to transmit with the transmission power that can be well received by the subscriber device farthest within the radius of the cell.

Second, referring to "transmission (upward) power from the repeater to the base station", in this case, as shown in FIG. 1, control is performed by an open circuit.

Because already closed loop control, the reception power can be set according to the subscriber or repeater position given the output of the base station.

Therefore, according to the increase or decrease of the reception power level of the repeater, the uplink power of the repeater can be adjusted. This is the same as the upstream power control method for subscribers in non-propagating shadow areas. Here, the open circuit means that the repeater (or subscriber device) controls its transmission output according to the reception level of the base station according to the level at which the transmission power of the base station is received.

That is, if the output transmitted from the base station is strong and the reception level is high, it means that the path loss is low or close to the base station. Therefore, in order to reduce interference to adjacent cells using the same frequency, it is necessary to adjust the transmission power of the repeater (or subscriber device) to maintain the minimum transmission quality.

Conversely, if the received power level is low, it means that the path loss is high or far from the base station. Therefore, the transmit power of the repeater (or subscriber device) should be increased to have a minimum transmit power for maintaining the already set transmission quality.

2 is a diagram illustrating a power control method between a repeater and a subscriber device according to the present invention.

Power control targets between the "relays" and "subscribers" include (1) "downward repeater transmission output" and (2) "upward subscriber transmission output".

First, referring to "transmission (down) power control from the repeater to the subscriber device", this case is the most essential part of the repeater power control, which will be described below.

The link budget for the radio shadow area is calculated by considering the rainfall time in the repeater. Initially, we want to adjust the power corresponding to the margin in the case of rain during open circuit control.

The control input detects the increase or decrease from the signal of the repeater receiving end receiving the signal transmitted from the base station. This information applies to downstream repeater output control.

 That is, the upstream transmission output increment of the repeater by the power control in the base station and the repeater period is applied to the repeater output incremental transmission and reception to the subscriber device. The reason why this is possible is that the initial transmission power transmitted from the repeater to the subscriber equipment is calculated by calculating the link budget for the shadow area as described above, and because the cell radius of the B-WLL is not so large, the change of climate is caused in the cell. Because it will not be different.

The change in the repeater reception output due to the change of weather between the base station and the repeater can be applied to the change of weather between the repeater and the subscriber equipment. Therefore, if the transmission power from the base station to the repeater is attenuated due to the rain, the reception power of the radio wave due to the rain will also be lowered in the case of the subscriber unit in the repeater.

Fig. 2 shows a receiver of a repeater for receiving a transmission signal of a base station and a transmitter of a repeater for amplifying the signal and transmitting the signal to a subscriber in a radio wave shadow area.

The amount of change in the dynamic range of the IF automatic gain controller (AGC) of the receiver is extracted, and the amount of output of the transmitter is adjusted again.

When the repeater is used in the above method, there are matters to be considered for power control.

First, the consideration is 'reception level over distance'. The location of the subscriber or repeater may be different in the cell of the base station. That is, some subscribers or repeaters can be placed very close to the base station. The subscriber or repeater has a relatively large reception power compared to the subscriber or repeater at the cell interface.

For example, if the distance from the center of the base station to the repeater location is r1 and the cell radius is r2, 20log ₁₀ (r2-r1) is the free path loss power corresponding to the difference between the two distances (r2-r1). ) Is input hard to the receiver. Therefore, it is necessary to adjust this amount of power through the dynamic range of the attenuator or IF automatic gain controller (AGC) at the repeater receiver. The same applies to subscribers in a cell or sector.

Second, the consideration is 'rainfall margin'. The power control range of the B-WLL base station apparatus is executed for the power margin M in the rain. Because, on a clear day, marginal surplus power can affect other cells using the same frequency and polarization. Thus, the same concept can also determine the power control range of the repeater. That is, the link budget is calculated in the area covered by the repeater, and the margin at the time of rain is calculated to control the downstream output of the repeater.

Third, the consideration is 'range of automatic gain controller (AGC)', which will be described in detail with reference to FIG. 3.

On the other hand, the following description will be given of "transmission (upward) power control from the subscriber apparatus to the repeater".

The uplink transmission power control of the subscriber receiving the signal through the repeater in the radio range is applied to the open circuit control method. This is the same as the uplink power control method of the line of sight (LOS) subscriber.

That is, the signal transmitted from the repeater is measured at the power level at the receiver of the subscriber to compensate for the increase and decrease of the transmit power level in consideration of the path loss (rain attenuation) from the repeater and the channel change according to the terrain.

3 is an explanatory diagram of the dynamic range characteristics of an automatic gain controller (AGC) of a repeater to which the present invention is applied.

The range of the repeater and subscriber automatic gain controller of the subscriber is determined by the following two variables giving loss of free space.

Variable 1 is the distance r, the radius of the cell, and variable 2 is the up and down frequency bands. The former defines up to 5km, the radius of a typical B-WLL, and the maximum loss due to the distance difference is about 14dB (= 20log ₁₀ 5), and the latter uses the domestic frequency band, 24 When defined as ~ 28 GHz, the maximum shift of the frequency loss due to the difference of bands is about 1.34dB (= 20log ₁₀ 28/24).

Thus, the sum of the losses of these two variables adds up to about 15.34 (= 14 + 1.34) dB, which is about 16 dB. On the other hand, in the case of 40 mm / h rainfall per hour with a cell radius of 5 km, if the loss due to rainfall is calculated for a signal of horizontal polarization, the loss is 5.2 dB / km.

Therefore, when setting the radius to 5Km, the margin can be defined as 26dB maximum compared to the rain. The result is a dynamic range of about 42 (= 16 + 26) dB. Therefore, the dynamic range of the receiver IF automatic gain regulator can be applied to the circuit design. The dynamic range of the IF AGC can be determined as shown in FIG. 3 from the concept in consideration of the distance and frequency shift and the margin during rain.

4 is an explanatory diagram of a receiver signal level of a repeater to which the present invention is applied and shows a relationship between the signal level of the repeater received from the base station and the dynamic range of the AGC.

The AGC configuration of the repeater receiver for the AGC dynamic range and the signal level considering the dynamic range are configured as follows.

Assume that the signal level past the antenna 401, circulator (or isolator) 402, and filter 403 of the receiver is -XdBm (R _thr + Field Margin).

Here, the threshold (R _thr ) is a received signal corresponding to the reference value of the B-WLL quality of service (for example, BER = 10 ^-6 ), and the field margin is an amount that gives a slight margin to the calculated value of R _thr . This is usually around 5dB.

Therefore, considering the dynamic range of 42 dB of the AGC obtained above, the range of the input signal at the low noise amplifier input section 404 is a maximum of -X + 42 dBm. In addition, the output of this signal through the low noise amplifier and the frequency down converter 404 becomes the input of the AGC circuit, the input signal of the AGC has a range of -3dBm to -45dBm. Here, it is assumed that the maximum input of AGC is -3dBm, which is a general value, and is an amount that can be actually implemented.

5 is a block diagram of an automatic gain controller AGC of a repeater to which the present invention is applied, and shows a circuit for detecting a change in signal level of an AGC input unit.

The output signal of FIG. 4 becomes the input of the variable amplifier shown in FIG.

The amount of change in the input signal is detected and applied as a variable for the increase and decrease control of the output signal of the repeater transmitter.

For reference, the general characteristics and functions of the AGC circuit in the band 40 MHz (/ CH) and the modulation method up to 16-QAM are described as follows.

The wide dynamic range is greater than 50 dB, gain flatness is 0.25 dB or less, and third order intermodulation IM3 is -55 dB or less. Temperature compensation AGC, input level detector, linearized voltage detector for ATPC level and monitoring, and manual gain adjustment.

6 is an explanatory diagram for a power control method in a broadband wireless subscriber network according to the present invention.

The power control target of the B-WLL device can be divided into two categories. First, power control between the base station and the subscriber, and second, power control between the base station and the repeater and the repeater and the subscriber. The repeater power control section corresponds to the second case.

In the case of the base station and the relay period, it is composed of power control of the base station sent from the base station to the repeater and repeater power control sent from the repeater to the base station. In addition, the relay between the subscriber and the subscriber is the power control of the repeater sent from the repeater to the subscriber and the power control of the subscriber sent from the subscriber to the repeater.

Power control methods include a closed loop and an open loop, and the best method can be selected in consideration of ease and efficiency in terms of circuit implementation and operation for the control section.

In the present invention, as shown in Figure 6, the power control method for the base station and repeater intervals, and repeater and subscriber intervals. In cells and sectors that do not use a repeater in one cell or sector, a power control method of a base station and a subscriber applies a closed circuit and an open circuit control method, respectively. However, when some propagation shadow areas exist in one cell and sector, a repeater is used.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains, and the above-described embodiments and accompanying It is not limited by the drawings.

As described above, the present invention can prevent interference between adjacent cells or adjacent channels due to unnecessary excessive transmission power through power control of the repeater, and also solve the transmission problem caused by signal attenuation during rainfall using repeater power control. Can be.

In addition, since the present invention applies an open circuit method of controlling the transmission power transmitted to the subscriber device of the repeater with the strength of the signal received from the base station, it is more economical than the method of applying the closed circuit method to the repeater. There is an excellent effect that can be configured simply.

Claims (13)

delete delete A method for controlling transmission power (downward power) from a broadband wireless subscriber network (B-WLL) repeater to a subscriber device, A downlink signal receiving step of receiving, by the repeater, a downlink signal from a base station; And A power control step of transmitting, by the repeater, the transmission power of the received downlink signal to the subscriber device according to the signal power level received from the base station; Transmitting power control method from the repeater to the subscriber device comprising a. The method of claim 3, wherein The power control step, And controlling the distance between the repeater and the subscriber device by using a distance, power margin during rain, and a range of an automatic gain controller. The method of claim 4, wherein The range of the automatic gain controller is, Transmitting power control method from a repeater to a subscriber device, characterized in that determined using the radius of the cell of the base station and the frequency band used. In the power control method in a broadband wireless subscriber network (B-WLL) repeater, An uplink power control step of receiving, by the repeater, an uplink signal from a subscriber device and adjusting the transmit power of the received uplink signal according to the signal power level received from the base station; And The downlink power control step of receiving the downlink signal from the base station, adjusting the transmission power of the received downlink signal according to the signal power level received from the base station, and transmitting the downlink signal to the subscriber station; Open circuit power control method in a repeater comprising a. The method of claim 6, The upward power control step, An uplink signal receiving step of receiving, by the repeater, an uplink signal from the subscriber device; And A first power control step of transmitting, by the repeater, the transmission power of the received uplink signal to the base station according to the signal power level received from the base station; Open circuit power control method in a repeater comprising a. The method of claim 7, wherein The first power control step, If the signal power received from the base station is higher than a predetermined reference value, the transmission power is lowered to the predetermined reference value, And if the signal power received from the base station is lower than the predetermined reference value, the transmission power is increased to the predetermined reference value. The method of claim 8, The downward power control step, A downlink signal receiving step of receiving, by the repeater, a downlink signal from the base station; And A second power control step of transmitting, by the repeater, the transmission power of the received downlink signal to the subscriber device according to the signal power level received from the base station; Open circuit power control method in a repeater comprising a. The method of claim 9, The second power control step, And controlling the distance between the repeater and the subscriber apparatus using a distance, power margin during rain, and a range of an automatic gain controller. The method of claim 10, The range of the automatic gain controller is, Open circuit type power control method in a repeater, characterized in that determined using the radius of the cell and the frequency band of the base station. In order to control the transmission power (downward power) to the subscriber device, to a broadband wireless subscriber network (B-WLL) repeater having a processor, A downlink signal receiving function for receiving the downlink signal from the base station by the repeater; And A power control function in which the repeater adjusts the transmission power of the received downlink signal according to the signal power level received from the base station and transmits it to the subscriber device; A computer-readable recording medium having recorded thereon a program for realizing this. For open-circuit power control, a broadband wireless subscriber network (B-WLL) repeater with a processor, An uplink power control function for receiving the uplink signal from the subscriber device and adjusting the transmission power of the received uplink signal to the base station according to the signal power level received from the base station; And The repeater receives a downlink signal from the base station, and adjusts the transmission power of the received downlink signal according to the signal power level received from the base station to transmit to the subscriber device A computer-readable recording medium having recorded thereon a program for realizing this.

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