KR100829860B1 - Method for power control which considers hand-over in land mobile satellite communication system containing Ancillary Terrestrial Components - Google Patents

Abstract

1. Technical field to which the invention described in the claims belongs

The present invention relates to a power control method considering handover in a satellite / mobile communication system including ATC (Ancillary Terrestrial Components).

2. Technical Challenges to be Solved by the Invention

The present invention applies an efficient power control and handover scheme using location information in a multi-user satellite / mobile communication system including an ATC to maintain a constant received signal-to-interference ratio of each user while satisfying a desired quality of service (QoS) The present invention provides a power control method considering handover.

3. The point of the solution of the invention

The present invention provides a power control method in a satellite / mobile communication system including ATC (Ancillary Terrestrial Components), comprising: acquiring current location information of a terminal; Obtaining current transmission power information of the terminal; And measuring a speed information of the terminal at a cell or a beam edge based on the position information, and comparing the current transmission power information with the current transmission power information using the reception diversity sheet according to the movement based on the speed information, And a first power control step of performing power control considering a handover based on a transmission power operation range of systems overlapping in an area where a terminal exists.

4. Important Uses of the Invention

The present invention is applied to a satellite or a mobile communication system including an ATC.

ATC, handover, power control, closed loop power control, open loop power control, round trip delay compensation

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power control method for a handover in a satellite / mobile communication system including an ATC,

1 is a diagram illustrating a configuration of a frequency reuse scheme in a satellite / mobile communication system including an ATC,

FIG. 2 is a configuration example of a satellite / mobile communication system including an ATC to which the present invention is applied,

FIG. 3 is a diagram illustrating a magnitude of a received signal according to a terminal traveling direction and time in a satellite / mobile communication system including an ATC to which the present invention is applied.

FIG. 4 is a flowchart of an embodiment of a power control method considering handover according to the present invention.

FIG. 5 is a detailed flowchart of a power control process in a case where a terminal location is within an ATC among power control methods considering handover according to the present invention.

FIG. 6 is a detailed flowchart of a power control process in a case where a terminal location is located in a satellite spot beam in a power control method considering handover according to the present invention.

FIG. 7 is a diagram illustrating a power control process in a case where a terminal position is located at a cell or a beam edge in a power control method considering handover according to the present invention.

FIG. 8 is a detailed flowchart of a power control process in a case where a terminal position is in a stationary state at a cell or a beam edge in a power control method considering handover according to the present invention.

FIG. 9 is a detailed flowchart of a power control process in a case where a terminal is in progress from an ATC cell to a satellite beam at a cell or a beam edge in a power control method considering handover according to the present invention.

FIG. 10 is a graph showing a power control method considering handover according to the present invention, in which a terminal position is shifted from a satellite beam to an ATC cell at a cell or a beam edge, from an ATC cell to another ATC cell and from a satellite spot beam to another satellite spot beam direction FIG. 2 is a detailed flowchart of a power control process when a mobile station is in progress; FIG.

DESCRIPTION OF REFERENCE NUMERALS

10: satellite 20: fixed base station

30: Gateway 40: PSDM / PDN

50: ATC controller 110 to 130: Spot beam

140,150: ATC 161,162: ATC antenna

171 to 173:

The present invention relates to a power control method considering handover in a satellite / mobile communication system including an ATC (Ancillary Terrestrial Components), and more particularly, to a power control method using an ATC Power control and a handover technique to maintain a desired signal-to-interference ratio of each user while satisfying a desired quality of service (QoS).

Let's take a look at Canada as an example of the introduction of ATC.

A mobile satellite network provides communication to remote and rural residents who are not provided with terrestrial cellular services.

In 1994, Canada was one of the countries that opened up its own markets to foreign mobile satellite operators in order to promote competition in the domestic satellite industry. Although cellular / PCS have reached more than 90% of the population, actual coverage is only part of the Canadian territory. Although, for many years, most satellite operators have provided satellite services to the Canadian market, they have very low subscribers compared to cellular and PCS services with 13 million subscribers.

Currently, the Canadian satellite industry is developing and planning a next generation mobile satellite. Next-generation satellites are using multi-beam antennas to increase spectral efficiency and are seeking to provide digital services that can communicate with small handheld terminals and surpass second-generation cellular PCS. Most satellites have sought IC (Industry Canada) to facilitate ATC development to provide mobile services, a component of MSS (Mobile Satellite Service). The main device in which ATC is installed is to use all of the allocated MSS spectrum in a given area. The system can extend service coverage to blocked areas and indoor areas in high-building satellite signals. In 2001, mobile satellite and ATC applications were registered with the US Federal Communications Commission (FCC) to operate as a next generation mobile satellite in the L band (1525 to 1559 / 1626.5 to 1660 MHz) and the 2 GHz band (1990 to 2025/2165 to 2200 MHz). In the LEO band (1610 ~ 1626.5 / 2483.5 ~ 2500MHz), mobile-satellite operators noted similar benefits. In February 2003, the FCC issued regulations and procedures authorizing mobile satellite service providers to submit applications for ATC service operation as part of the mobile satellite service provision in the three bands mentioned above. In addition, the FCC has reassigned some of the bands of the 2GHz MSS spectrum (15 + 15 MHz) to ground fixed and mobile services and maintained the 2000-2020 MHz and 2180-2200 MHz bands for mobile satellite services.

Looking at the basic concepts of satellite / mobile communication systems, including ATC, different technologies and ATC proposals have been submitted to increase spectral efficiency within the same licensed MSS band. Among them, geostationary MSS operators, Mobile Satellite Ventures (MSV) Canada, provided the idea of frequency reuse by exploiting the unserviceable geographical advantage of specific MSS channels due to intra-system interference. MSV's next-generation system tries to use a relatively large number of small spot beams on the Earth's surface. These spot beams can provide enough satellite coverage over the range of 400 to 500 km on the surface.

1 is a diagram illustrating a configuration of a frequency reuse scheme in a satellite / mobile communication system including an ATC.

As shown in FIG. 1, the geostationary satellite 10 having sufficient power provides communication services with three spot beams 110 to 130.

Spot beams 110 operating at F1 frequencies serve rural areas with fewer populations and fewer high floors whereas spot beams 120 and 130 operating at F2 and F3 frequencies are crowded and have a large number of buildings, ATC system is used to cover the blocked urban area.

In order for the ATC system to reuse the spot beam 110 operating at frequency F1, the distances between the two systems should be sufficiently long to not interfere with each other.

That is, the ATC concept of the MSV means that the ATC can use the frequency in the frequency F1 region that the satellite does not use if it can be distinguished between the terrestrial transmitter using the same frequency and the MSS satellite beam.

ATC implementation for non-geostationary orbit (NGSO) MSS system such as Globalstar is very complicated because it moves at a high speed and several MSS satellites are visible at any moment, but NGSO like multi-beam antenna And reuse the assigned MSS frequency as the selected satellite antenna coverage beam.

Recently, handover and power control techniques for satellite / mobile communication systems including ATC are being developed.

For example, "SYSTEMS AND METHODS FOR HANDOVER BETWEEN SPACE BASED AND TERRESTRIAL RADIOTHERMINAL COMMUNICATIONS, AND FOR MONITORING TERRESTRIALLY REUSED SATELLITE FREQUENCIES AT A RADIOTERMINAL TO REDUCE POTENTIAL INTERFERENCE (US 6,879,829) (hereinafter referred to as" first prior art ") The first prior art shows a handover between ATC, cellular and satellite.

That is, the first prior art shows an algorithm that a terminal receives position information using a Global Positioning System (GPS) or other technology, determines a threshold value of the position information and a received signal, and performs a handover.

However, in the first prior art, only the process of performing handover between ATC / cellular / satellite is shown. In other words, the position information is monitored in real time prior to the handover to perform efficient power control in the corresponding system, and only a general power control scheme is adopted. In the satellite spot beam or in the vicinity of the cell, The over-execution process is not explicitly shown. If power control without consideration of handover is performed as described above, the system becomes very inefficient in terms of system capacity. In the first prior art, there is a round trip delay problem in the closed loop and open loop power control in the pre-handover stage.

Here, there are two general power control schemes: an open loop power control scheme and a closed loop power control scheme.

The 'open loop power control scheme' is basically an approximate power control that is performed under the assumption that the forward and reverse path losses are equal. In fact, since the forward and backward fading conditions are very different in time, the accuracy of the method of estimating the received power reaching the base station based on the strength of the signal received by the terminal and determining its output is very insufficient. In order to improve the inaccuracy, the base station informs the terminal of the strength of the received signal received by the terminal at an arbitrary time, so that the terminal can control the terminal output so that the signal strength reaching the base station is constant . This function is called 'closed loop power control technique'.

In a more accurate expression, the base station determines whether the base station reception demodulation unit is in an arbitrary state based on a signal interference ratio reference value determined by outer loop power control according to a target frame error rate (FER) value of a reverse communication channel designated by an operator To the signal-to-interference ratio value measured at each time of the reception. At this time, if the measured value is larger than the reference value, the terminal is instructed to lower the output to a certain value, and if the measured value is smaller than the reference value, the terminal is instructed to increase the value by a certain value. Here, the fact that the measured value is larger than the set reference value means that the terminal signal arrives at the base station larger than the minimum power required by the base station. This means that the terminal transmits an unnecessarily large output, Indicating that it has a lot of influence.

In addition, the first prior art does not provide a technique for efficiently performing power control between the satellite / ATC / cellular after handover to an arbitrary system.

As an example of the prior art for performing power control after performing handover, an example of the prior art is disclosed in US patent application Ser. Nos. 2006/0094352 (hereinafter referred to as " Second Prior Art Quot;). The second prior art provides an efficient power control system between the satellite, the terrestrial base station and the terminal.

However, in the second prior art, direct power control is performed with a mobile station in an area where a line of sight (LOS) exists. In this method, when the current received signal is measured and the power control is compensated for the next slot or frame, The delay time results in meaningless power control. If the LOS is not present, the power control command is provided to the terminal using the terrestrial base station (i.e., the power control command is indirectly provided through the ATC in an area without the LOS) This is a power control technique which does not consider the round trip delay time at the same time while feedbacking it at all.

That is, the second prior art deals with a power control technique that does not consider round-trip delay time.

As described above, conventionally, only a technique of checking handover power and QoS in a satellite / mobile communication system including an ATC is disclosed. In the handover aspect, unlike the present invention, if the terminal's transmission power exceeds a threshold and total user interference exceeds a limit and the received satellite signal quality exceeds a threshold, even if the user continues to communicate with the ATC If possible, it is handed over from the ATC to the satellite.

For reference, in the present invention, power and system capacity of a terminal can be increased by applying appropriate maximum power and minimum power to a corresponding system range (satellite or ATC) due to location information of a terminal. Furthermore, if the terminal is located at the edge remote from the served ATC or satellite spot beam, the present invention performs efficient handover using receive diversity after receiving both satellite spot beams and ATC signals. That is, in the present invention, the terminal receives the location information of a terminal in an ATC, a satellite, or a mobile communication system, sets a minimum power and a maximum power appropriate to the system, and then transmits a highly advanced power control technique The system capacity and power efficiency can be increased and the terminal power consumption can be lowered. In this way, it is possible to combine the signals received from both systems (receive diversity) in order to monitor the position information in real time and to get out of coverage of the system (that is, at the cell / beam edge) And at the same time performs a handover to provide seamless communication service to the user.

Also, according to the prior art, unlike a terrestrial mobile communication system, a geostationary based satellite / mobile communication system has only a slight advantage due to the considerably long round trip delay between the terminal and the satellite / base station. That is, in a power control part of a satellite / mobile communication system including an existing ATC, a power control technique of a terminal served by an ATC is based on a combination of an open loop and a closed loop power control of a terrestrial system, The power control technique of the power amplifier is not disclosed. However, unlike the terrestrial mobile communication system, the mobile communication system has only a slight benefit of the open / closed loop power control because of the considerably long round trip delay between the terminal and the satellite / ATC.

However, in order to solve this problem, in the present invention, the transmission power / phase information that has not yet been experienced in the receiver through the satellite / terrestrial channel is used through monitoring.

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above problems, and it is an object of the present invention to provide an efficient power control and handover scheme using location information in a multiuser satellite / And it is an object of the present invention to provide a power control method considering a handover in order to maintain a received signal-to-interference ratio of a user constant.

Other objects and advantages of the present invention will become apparent from the following description, and it will be understood by those skilled in the art that the present invention is not limited thereto. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to an aspect of the present invention, there is provided a power control method in a satellite / mobile communication system including ATC (Ancillary Terrestrial Components), comprising: acquiring current location information of a terminal; Obtaining current transmission power information of the terminal; And measuring a speed information of the terminal at a cell or a beam edge based on the position information, and comparing the current transmission power information with the current transmission power information using the reception diversity sheet according to the movement based on the speed information, And a first power control step of performing power control considering handover based on a transmission power operation range of systems overlapping the area where the terminal exists.

In addition, the present invention recognizes the location of the terminal based on the location information, and determines the current transmission power information in the ATC cell or satellite spot beam and the transmission power operation of the system corresponding to the area in which the terminal exists And a second power control step of performing closed loop or open loop power control based on the " range ".

In the present invention, not only a power control algorithm but also a handover algorithm based on rate information at a cell / beam edge are additionally proposed.

The present invention based on location information provides open-loop power control in an area where an LOS exists, while performing closed loop power control in an area without an LOS, while providing communication services seamlessly in a handover process.

Particularly, the present invention can reduce the transmission power of a mobile station by compensating the round trip delay time even in the open loop power control.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: There will be. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating a configuration of a satellite / mobile communication system including an ATC to which the present invention is applied.

In a satellite / mobile communication system including ATC, a satellite 10 having sufficient power provides communication services through three spot beams 110 to 130 operating with frequencies F1, F2 and F3, respectively. do.

The areas where the population is dense and the satellite signals are blocked by the high-rise buildings (spot beams 120 and 130 operating with F2 and F3 frequencies) re-use the Mobile Satellite Service (MSS) band by installing ATC systems 140 and 150.

That is, as shown in FIG. 2, the ATC antenna 161 and the ATC antenna 162 are provided to provide communication services with F1 and F2 different from the satellite spot beam F3 corresponding to the two ATCs 140 and 150, respectively.

In FIG. 2, a scenario for communicating with a terminal and a satellite mobile communication or ATC system in a satellite / mobile communication system including an ATC is as follows.

First, when the terminal 172 is located within the spot beam 110 operating with the F1 frequency and receives position information, the terminal 172 transmits data to the satellite 10 using the MSS band uplink 184 do.

The satellite 10 then transmits the data to the fixed base station 20 using the downlink 181 of the feeder link and transmits data from the fixed base station 20 using the uplink 181 of the feeder link after data processing Data is received.

Next, the satellite 10 transmits data to the corresponding terminal 172 using the MSS band downlink 184. [

If the terminal 171 desires to communicate with the terminal 173, the terminal 171 receives the location information and reuses the F1 192 of the MSS band uplink to the ATC base station 161 in the ATC cell 140 . The ATC base station 161 transmits data to the ATC controller 50 and the ATC controller 50 transmits the data to the gateway 30 through a public switched data network (PSDN) / a public data network (PDN) ). The fixed ground station 20 then transmits the satellite link 10 using the Peter link uplink 181 and the satellite 10 transmits the data to the terminal 173 existing in the spot beam 120.

Then, the terminal 173 transmits data to the terminal 171 in the ATC cell 140 of the spot beam 130 through the above process.

3 is an exemplary diagram illustrating the magnitude of a received signal according to a terminal direction and time in a satellite / mobile communication system including an ATC to which the present invention is applied.

The satellite spot beam 130 has the MSS band frequency F3 and the two ATC cells 140 and 150 reuse the MSS band frequencies F1 and F2, respectively.

If the terminal direction is equal to "301 ", the size of the received signal over time is equal to" 300 ".

Handover and power control are divided into six major parts.

When power control is performed in the satellite spot beam 130 and power control and handover are performed in the satellite spot beam 130 to the ATC cell 140 or 150 and the ATC cell 140 or 150 The power control and handover from the ATC cell 140 or 150 to the other ATC cell 150 or 140 is performed in the fourth place in the ATC cell 140 or 150, When power control and handover are performed with the beam 130, power control and handover from the satellite spot beam 130 to another satellite spot beam 120 are performed.

Here, the reception signal 340 represents a signal received in the direction 301 in which the terminal proceeds with the power transmitted from the ATC base station 161 in the ATC cell 140, and the reception signal 350 indicates the signal received in the ATC cell 150 denotes a signal received according to the direction 301 of the terminal in which the ATC base station 162 transmits power and the received signal 360 indicates the signal transmitted by the satellite spot beams 130 and 120 Quot; direction " In particular, high handover and power control is required at a cell or beam boundary point such as "310, 320, 330 ".

4, the process of determining the location information in the satellite / mobile communication system including the ATC and performing efficient power control in the corresponding system will be described in more detail.

4 is a flowchart illustrating an overall power control method in consideration of handover according to an embodiment of the present invention.

First, at a data transmission start point for communication by the terminal, the terminal acquires corresponding position and speed information of the terminal using GPS or other technology (401).

Then, the terminal acquires transmission power information such as a minimum power (Pmin) and a maximum power (Pmax) in a search table storing location information (402).

Next, the position information is determined. If the terminal position is present in the ATC cell (403), power control is performed (404), which will be described later with reference to FIG.

On the other hand, if the terminal location is present in the satellite spot beam (403), power control is performed (405), which will be described later with reference to FIG.

On the other hand, if the terminal position is present at the edge of the cell (Step 403), the power control is performed (Step 406), which will be described with reference to FIG.

FIG. 5 is a detailed flowchart of a power control procedure 404 in the case where a terminal location is within an ATC, among power control methods considering handover according to the present invention.

If a terminal based on location information exists in the ATC cell (403), a target signal to interference ratio (SIR) is obtained using an open loop power control technique and a round trip delay compensation algorithm (501).

The target SIR, the current SIR and the next transmission power decision are as follows.

First, the power of the average received signal is measured using the following equation (1) of Friis.

은 각각 ATC 전송전력, ATC 안테나 이득, 단말기 안테나 이득, 파장, 단말기와 ATC 사이의 거리, 그리고 거리에 따른 손실(여기서, 지수 n은 ATC 셀 내에 단말기가 존재할 때 3~4를 가지고, 위성 내에 존재할 때 2~3을 가짐)을 나타낸다.In Equation (1), P _t , G _t , G _r , λ, d, and

Is a loss due to ATC transmission power, ATC antenna gain, terminal antenna gain, wavelength, distance between terminal and ATC, and distance, where exponent n is 3 to 4 when there is a terminal in ATC cell, 2 to 3 times).

Then, the target SIR (Signal-to-Interference Ratio) is predicted by measuring the FER (Frame Error Rate) / BER (Bit Error Rate), and the SIR of the signal (Equation 1) (2).

In Equation (2), d (t), g (t), p (t), and s (t) refer to a data symbol, a channel gain, a transmission power, and a known pilot symbol.

The next transmission power decision using the open-loop power control and the round-trip delay compensation algorithm is shown in Equation (3) below.

In [Mathematical Expression 3], τ means a predetermined time to report to the base station (usually 20 ms), and ΔP (t) is as shown in the following equation (4).

는 다음의 [수학식 5]와 같다.In Equation (4), the round trip delay compensation algorithm

Is expressed by the following equation (5).

Then, the closed loop power control scheme and the round trip delay compensation algorithm are simultaneously performed 502 with the target SIR variable, and the next transmission power decision is as shown in Equation (6).

In Equation (6), the power control command PCC is obtained by performing the following algorithm (Equation (7)).

(502), and compares the bit error rate and the received signal quality (QoS) with an arbitrary threshold (503). If the bit error rate and the received signal quality (QoS) are lower than the threshold (504), the operation range and the position of the transmission power of the current terminal are checked.

If the current transmission power of the terminal is between the minimum power (Pmin) and the maximum power (Pmax) of the ATC cell (that is, within the operating range of the transmission power of the ATC cell) And obtains a new target signal to interference ratio (SIR) using the open loop power control scheme and the round trip delay compensation algorithm, and determines whether the current transmission power of the terminal is within the operating range of the transmission power of the ATC cell (minimum power (Pmin) (Pmax)), the mobile terminal moves to step " 403 "to acquire the position information, moves to the corresponding system, and performs another power control process.

If the comparison result (503), the bit error rate, and the received signal quality (QoS) are above a certain threshold, a closed loop power control technique and a round trip delay compensation algorithm are continuously performed (502).

FIG. 6 is a detailed flowchart of a power control process 405 in a case where a terminal location is located in a satellite spot beam in a power control method considering handover according to the present invention.

Unlike ATC and terrestrial systems, for example, a geostationary-based system requires a round-trip delay of at least 0.5 seconds, which is a significant overhead for system operation. Therefore, in order to minimize the system complexity, the initial information (target SIR, terminal initial transmission power) uses closed loop power control technique, and then power control adopts open loop power control technique.

First, if the terminal based on the position information exists in the satellite spot beam (403), the target SIR is obtained using the closed loop power control technique and the round trip delay compensation algorithm of Equation (8) (601).

delete

In Equation (8), when the satellite sends a response signal, the ACK variable is dealt with by Equation (4). If there is no response, the ACK response signal is transmitted until the terminal receives the ACK response signal. Increase monotone.

2, when the terminal 172 transmits a preamble signal to the satellite 10 to have the initial transmission power and the target SIR variable, the satellite 10 transmits the preamble signal to the fixed ground station 20, And transmits the terminal preamplifier signal using the downlink 181. Thereafter, the fixed ground station 20 computes the initial transmission power and the target SIR variable of the terminal 172 and transmits the uplink 181 of the feeder link to the satellite 10 to transmit the acquired information to the terminal 172 Lt; / RTI > The satellite 10 then transmits initial transmission power and target SIR information to the terminal 172 via the MSS band downlink 184. [

Referring again to FIG. 6, an open loop power control technique and a round trip delay compensation algorithm are performed using Equation (3) (602).

(602), compares the bit error rate and the received signal quality (QoS) to an arbitrary threshold (603), and if the bit error rate and the received signal quality (QoS) are below the threshold (Step 604), and checks the operation range and the position of the current transmission power of the terminal.

If the current transmission power of the terminal is between the minimum power Pmin and the maximum power Pmax of the satellite spot beam (that is, within the operating range of the transmission power of the satellite spot beam) (SIR) using the closed loop power control scheme and the round trip delay compensation algorithm, and determines whether the current transmission power of the mobile station is within the operating range of the transmission power of the satellite spot beam (minimum power Pmin - The maximum power Pmax), the mobile terminal moves to step 403 to acquire position information, moves to the corresponding system, and performs another power control process.

If the comparison result (603), the bit error rate, and the received signal quality (QoS) are equal to or greater than a certain threshold value, the open loop power control technique and the round trip delay compensation algorithm are continuously performed (602).

FIG. 7 is a diagram illustrating a power control procedure 406 when a terminal location is located at a cell or a beam edge in a power control method considering handover according to an embodiment of the present invention.

Receive diversity is used to increase the SIR of the received signal (701).

Thereafter, when the terminal is in the stopped state 702, moving from the ATC cell to the spot beam 703, moving from the spot beam to the ATC cell 704, moving from the ATC cell to the ATC cell 705, (706) when the beam is moving from the beam to the spot beam, and performs appropriate power control and handover corresponding thereto.

FIG. 8 is a detailed flowchart of a power control procedure 702 of a power control method considering handover according to the present invention when a terminal position is stationary at a cell or a beam edge.

When the terminal is in a stationary state at a cell or a beam edge (step 801), the terminal recognizes the BCH (Broadcast CHannel) by receiving the most received two systems using the location information first 802). At this time, in order to increase the reception signal interference ratio, reception diversity is used.

If the terminal receives the power transmitted from the ATC cell and another ATC cell (803) by measuring the average power of the received signal, the same power control process as when the position of the terminal described in FIG. 5 exists in the ATC cell (404).

On the other hand, if the terminal receives the power transmitted from the spot beam and another spot beam (805), the same power control procedure (405) as the case where the position of the terminal described in FIG. 6 exists in the spot beam is performed.

On the other hand, if the terminal is receiving the power transmitted from the ATC cell and the spot beam (804), an arbitrary timer is set to use the open loop power control technique and the round trip delay compensation algorithm (808) After obtaining the target SIR (806), power control is performed using a closed loop power control technique and a round trip delay compensation algorithm (807). If the timer does not exceed the predetermined time (808), the target SIR is obtained using the closed loop power control technique and the round trip delay compensation algorithm (809), and then the open loop power control technique and the round trip delay compensation algorithm To perform power control (810). At this time, if the position information and the speed information are correct (811) without exceeding a certain time (execution time), the process moves to the step 806 and performs the above procedure again.

The closed-loop power control scheme and the open-loop power control scheme are exchanged for a predetermined time period in order to uniformly control the power transmitted to the ATC cell and the satellite spot beam.

If it is out of the predetermined time (execution time) (steps 808 and 811), the process proceeds to step 403 to acquire the position information, move to the corresponding system, and perform another power control process.

FIG. 9 is a detailed flowchart of a power control procedure 703 of a power control method considering handover according to the present invention when a terminal is in progress from an ATC cell to a satellite beam at a cell or a beam edge.

If the terminal is not in a stationary state 702 at the edge of a cell or a beam and recognizes positional information and speed information and if the terminal is moving from the ATC cell range to the satellite spot beam 901, 701). In the state where the target SIR information is acquired, only the open loop power control scheme and the round trip delay compensation algorithm are performed (902), and a handover process is performed as desired. That is, the reception power of both the ATC cell and the spot beam is combined using the reception diversity, and the average power is measured to acquire the target SIR.

At this time, in the power control process 902, the bit error rate and the received signal quality (QoS) are compared with an arbitrary threshold (903). If the bit error rate and the received signal quality (QoS) The operating range and position of the current transmission power of the terminal are checked (904).

If the current transmission power of the terminal is between the minimum power Pmin and the maximum power Pmax of the ATC cell or the satellite spot beam, (905) by using the closed loop power control scheme and the round trip delay compensation algorithm (905), the process moves to step 902 and the open loop power control scheme and the round trip delay compensation (Pmin) to the maximum power (Pmax) of the transmission power of a large value among the ATC cell or the satellite spot beam. If the current transmission power of the terminal exceeds 403 "Step to determine the location information, and then move to the corresponding system to perform another power control process.

If the comparison result (903), the bit error rate, and the received signal quality (QoS) are equal to or greater than a certain threshold, the open loop power control technique and the round trip delay compensation algorithm are continuously performed 902.

If the terminal does not move from the ATC cell to the spot beam (901), the procedure of FIG. 10 is performed.

FIG. 10 is a graph showing a power control method considering handover according to the present invention, in which a terminal position is shifted from a satellite beam to an ATC cell at a cell or a beam edge, from an ATC cell to another ATC cell and from a satellite spot beam to another satellite spot beam direction FIG. 2 is a detailed flowchart of a power control process when a mobile station is in progress; FIG.

If the terminal is not in the stationary state 702 at the cell or beam edge, the mobile station 101 is already using the receive diversity (701 in FIG. 7) if it is moving from the satellite spot beam to the ATC cell 101, The target SIR information is obtained, and only the closed loop power control scheme and the round trip delay compensation algorithm are performed (102).

At this time, in the power control procedure 102, the bit error rate and the received signal quality (QoS) are compared 103 with an arbitrary threshold, and if the bit error rate and the received signal quality (QoS) The operating range and position of the current transmission power of the terminal are examined (104).

If the current transmission power of the terminal is between a minimum power Pmin and a maximum power Pmax of a large value among the ATC cell or satellite spot beam (i.e., the transmission power of the ATC cell or the stomach spot beam (SIR) is obtained using the open loop power control technique and the round trip delay compensation algorithm (105), and then the process proceeds to step 102, where the closed loop power control technique and the round trip delay When the current transmission power of the terminal is out of the operating range (minimum power (Pmin) to maximum power (Pmax)) of the transmission power of a large value among the ATC cell or the satellite spot beam, 403 "to acquire the location information and move to the corresponding system to perform another power control process.

If the comparison result (103), the bit error rate, and the received signal quality (QoS) are equal to or greater than a certain threshold value, a closed loop power control technique and a round trip delay compensation algorithm are continuously performed.

On the other hand, if the terminal recognizes the location information and the speed information and the terminal is not in the stationary state 702 at the cell or the beam edge, if the terminal is moving from the ATC cell to another ATC cell (106) Performs the same power control procedure 404 as when the location is within the ATC cell.

On the other hand, if the terminal recognizes the location information and the speed information and the terminal is not in the stationary state 702 at the cell or beam edge, if the terminal is moving from the satellite spot beam to another satellite spot beam (106) The same power control procedure 405 as when the position of the described terminal is within the spot beam is performed.

Of course, when the above process is performed, the speed information and the position information are monitored in real time, the speed information and the position information are reflected, and a proper power control is performed to perform a handover procedure.

The method of the present invention as described above may be embodied as a program and stored in a computer-readable recording medium (such as a CD-ROM, a RAM, a ROM, a floppy disk, a hard disk, or a magneto-optical disk). Such a process can be easily carried out by those skilled in the art and will not be described in detail.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings.

The effects of the present invention are as follows.

A satellite or mobile communication system including an existing ATC deals with a technique of handover by checking received power and QoS (Quality of Service). However, according to the present invention, after the terminal receives location information of a terminal in an ATC, satellite, or mobile communication system, the terminal sets a minimum power and a maximum power suitable for the corresponding system and then uses a highly advanced power control technique Thereby improving the system capacity and power efficiency and lowering the terminal power consumption.

When the position and speed information is monitored in real time to overcome the coverage of the corresponding system, that is, at the cell / beam edge, the present invention combines the signals received from both systems The handover can be performed with a more efficient power control and at the same time a seamless communication service can be provided to the user.

Also, according to the existing method, unlike the terrestrial mobile communication system, the periodic-based satellite / mobile communication system has only a slight advantage due to the considerably long round-trip delay between the terminal and the satellite / base station. According to the present invention, the above problem can be solved by monitoring the use of the transmission power / phase information which has not yet experienced the satellite / terrestrial channel in the receiver.

Claims (11)

1. A power control method in a satellite / mobile communication system including ATC (Ancillary Terrestrial Components) Acquiring current location information of the terminal; Obtaining current transmission power information of the terminal; And The mobile station recognizes the position of the mobile station based on the position information, measures the speed information of the mobile station at a cell or a beam edge, and calculates the current transmission power information using the reception diversity sheet, A first power control step of performing power control considering handover based on a transmission power operation range of systems overlapping with an area in which a mobile station exists Wherein the ATC includes at least one ATC that includes a plurality of ATCs. The method according to claim 1, Recognizes the position of the terminal based on the positional information, and detects the position of the terminal based on the current transmission power information and the transmission power operation range of the system corresponding to the area in which the terminal exists, within the ATC cell or satellite spot beam A second power control step of performing loop or open loop power control Wherein the ATC includes a plurality of ATCs. 3. The method of claim 2, Wherein the second power control step comprises: Recognizing a position of the terminal based on the position information; If the terminal is present in the ATC cell, it performs a closed loop power control based on the current transmission power information in the ATC cell and the transmission power operation range of the ATC cell corresponding to the area in which the terminal exists Performing a first power control; And The method of claim 1, further comprising: if the terminal is in the satellite spot beam, determining an open loop based on the current transmit power information within the satellite spot beam and the transmit power operating range of the satellite spot beam corresponding to the region in which the terminal is located, Performing a second power control step of performing power control Wherein the ATC includes at least one ATC that includes a plurality of ATCs. The method of claim 3, Wherein the first power control step includes: Measuring an average received signal power; Obtaining a target signal to interference ratio (SIR) using an open loop power control technique and a round trip delay compensation algorithm; Performing power control using a closed loop power control scheme and a round trip delay compensation algorithm using the obtained target SIR variable; Comparing the bit error rate and the received signal quality to a predetermined threshold during a closed loop power control; If the bit error rate and the received signal quality are lower than the predetermined threshold value as a result of the comparison, checking the operation range and the position of the current transmission power of the terminal; And If it is determined that the current transmission power of the MS is between the minimum power and the maximum power of the ATC cell, a new target SIR is obtained using the open loop power control technique and the round trip delay compensation algorithm, Performing power control using a control scheme and a round trip delay compensation algorithm Wherein the ATC includes at least one ATC that includes a plurality of ATCs. The method of claim 3, Wherein the second power control step comprises: Measuring an average received signal power; Acquiring a target signal to interference ratio (SIR) using a closed loop power control technique and a round trip delay compensation algorithm; Performing power control using an open loop power control technique and a round trip delay compensation algorithm using the acquired target SIR parameters; Comparing the bit error rate and the received signal quality to a predetermined threshold during an open loop power control; If the bit error rate and the received signal quality are lower than the predetermined threshold value as a result of the comparison, checking the operation range and the position of the current transmission power of the terminal; And If it is determined that the current transmission power of the terminal is between the minimum power and the maximum power of the satellite spot beam, a new target SIR is obtained using the closed loop power control technique and the round trip delay compensation algorithm, A step of performing power control using a power control technique and a round trip delay compensation algorithm Wherein the ATC includes at least one ATC that includes a plurality of ATCs. 6. The method according to any one of claims 3 to 5, In the first power control step, When the terminal is moving from the ATC cell to the satellite spot beam when the terminal is stationary at the cell or the beam edge, depending on whether the terminal is moved by the velocity information using receive diversity, When the terminal is moving from the satellite spot beam to the ATC cell, when the terminal is moving from the first ATC cell to the second ATC cell, when the terminal is moving from the first satellite spot beam to the second satellite spot beam Power control and handover are performed in a satellite / mobile communication system including an ATC. The method according to claim 6, The step of performing the power control when the terminal is stationary at the cell or the beam edge, Measuring speed information of the terminal; Recognizing, by the terminal, two systems that are received with the largest signal using the receive diversity when the terminal is in a stationary state at the cell or beam edge based on the measured speed information of the terminal; Measuring an average received signal power; Performing the first power control step when the terminal receives the power transmitted from the first and second ATC cells; Performing the second power control performing step when the terminal receives the power transmitted from the first satellite spot beam and the second satellite spot beam; Setting a predetermined timer when the terminal receives the satellite spot beam and the power transmitted from the ATC cell; And During the predetermined timer driving time, the target SIR is obtained using the open loop power control technique and the round trip delay compensation algorithm, and the power control is performed using the closed loop power control technique and the round trip delay compensation algorithm. And obtaining a target SIR using a round trip delay compensation algorithm and performing power control using an open loop power control technique and a round trip delay compensation algorithm Wherein the ATC includes at least one ATC that includes a plurality of ATCs. The method according to claim 6, And performing power control when the terminal is moving from the ATC cell to the satellite spot beam at the edge of the cell or the beam, Measuring speed information of the terminal; When the terminal according to the measured speed information of the terminal is moving from the ATC cell to the satellite spot beam at the cell or beam edge, the reception power of both the ATC cell and the satellite spot beam Measuring an average power; Obtaining a target SIR; Performing an open loop power control technique and a round trip delay compensation algorithm with the obtained target SIR to perform power control and handover; Comparing the bit error rate and the received signal quality to a predetermined threshold during an open loop power control; If the bit error rate and the received signal quality are lower than the predetermined threshold as a result of the comparison, checking an operation range and a position of a transmission power of the terminal at present; And If it is determined that the current transmission power of the terminal is between a minimum power and a maximum power of a large value among the ATC cell or the satellite spot beam, a new target SIR is acquired using a closed loop power control technique and a round trip delay compensation algorithm And then performing power control using the open loop power control technique and the round trip delay compensation algorithm Wherein the ATC includes at least one ATC that includes a plurality of ATCs. The method according to claim 6, And performing power control when the terminal is moving from the satellite spot beam to the ATC cell at the cell or beam edge, Measuring speed information of the terminal; When the terminal according to the measured speed information of the terminal is moving from the satellite spot beam to the ATC cell at the cell or beam edge, the reception power of both the ATC cell and the satellite spot beam Measuring the average power by combining; Obtaining a target SIR; Performing power control and handover by performing a closed loop power control technique and a round trip delay compensation algorithm with the obtained target SIR; Comparing the bit error rate and the received signal quality to a predetermined threshold during a closed loop power control; If the bit error rate and the received signal quality are lower than the predetermined threshold as a result of the comparison, checking an operation range and a position of a transmission power of the terminal at present; And If it is determined that the current transmission power of the terminal is between a minimum power and a maximum power of a large value among the ATC cell or the satellite spot beam, a new target SIR is obtained using the open loop power control technique and the round trip delay compensation algorithm And then performing power control using the closed loop power control technique and the round trip delay compensation algorithm Wherein the ATC includes at least one ATC that includes a plurality of ATCs. The method according to claim 6, And performing power control when the terminal is moving from the first ATC cell to the second ATC cell at the edge of the cell or the beam, Wherein the terminal measures the speed information of the terminal and when the terminal according to the measured speed information of the terminal is moving from the first ATC cell to the second ATC cell at the edge of the cell or the beam, 1 and the second ATC cell to measure the average power and to perform the first power control step. In the satellite / mobile communication system including the ATC, power control considering handover Way. The method according to claim 6, And performing power control when the terminal is moving from the first satellite spot beam to the second satellite spot beam at the edge of the cell or the beam, Measuring the speed information of the terminal and using receive diversity when the terminal according to the measured speed information of the terminal is moving from the first satellite spot beam to the second satellite spot beam at the cell or beam edge And the average power is measured by combining received power of both the first satellite spot beam and the second satellite spot beam, and performing the second power control performing step. In the satellite / mobile communication system including the ATC, / RTI >

Images