KR101257104B1 - Femto cell base-station apparatus and self-configuring method thereof - Google Patents

Femto cell base-station apparatus and self-configuring method thereof Download PDF

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KR101257104B1
KR101257104B1 KR20090092599A KR20090092599A KR101257104B1 KR 101257104 B1 KR101257104 B1 KR 101257104B1 KR 20090092599 A KR20090092599 A KR 20090092599A KR 20090092599 A KR20090092599 A KR 20090092599A KR 101257104 B1 KR101257104 B1 KR 101257104B1
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South Korea
Prior art keywords
preamble
femtocell
base station
macrocell
correlation value
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KR20090092599A
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Korean (ko)
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KR20100048875A (en
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장성철
윤철식
안지환
상영진
김광순
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삼성전자주식회사
한국전자통신연구원
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Priority to KR1020080108045 priority
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Priority claimed from US12/609,305 external-priority patent/US8374138B2/en
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W52/00Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04TPC
    • H04W52/18TPC being performed according to specific parameters
    • H04W52/24TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • H04W52/243TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters taking into account interferences
    • H04W52/244Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]

Abstract

According to a self-configuration method of a femtocell base station, a preamble is extracted from signals received from adjacent macrocells and femtocells. The transmit power of the femtocell base station is set using the extracted macrocell preamble. In addition, the preamble of the femtocell base station is selected using a correlation value between the macrocell preamble and the pre-stored femtocell preamble. In addition, resources for data transmission of the femtocell base station are allocated in consideration of the magnitude of signal interference between adjacent macrocells and femtocells.
Figure R1020090092599
Femtocell, macrocell, self-configuration, preamble, correlation

Description

Femto cell base-station apparatus and self-configuring method

The present invention relates to a femtocell base station apparatus and a self setting method. More specifically, when a femtocell base station apparatus is installed in an orthogonal frequency division multiple access (OFDMA) based cellular mobile communication network, the femtocell base station detects the surrounding macrocell environment and allocates its own configuration and resources accordingly. It relates to a device and a self setting method.

Femto cell (Femto cell) is a small base station that provides a mobile communication service to an area of about 30m radius, also known as Home Node-B (Home Node-B). Femtocells are mainly installed in areas or shadowed areas where radio waves of macro cells are degraded, such as inside homes or buildings, and are installed for the purpose of compensating the quality of mobile communication services.

Existing femtocell base station was developed based on the Code Division Multiple Access (CDMA) network, and aims to expand the cell area. And no commercial femtocell base station based on OFDMA has been proposed.

Standardization organizations such as The 3rd Generation Partnership Project (3GPP) and 3rd Generation Partnership Project Long Term Evolution (LTE) and Institute of Electrical and Electronics Engineers (IEEE) 802.16m are currently working on standard technologies and requirements for femtocell base stations. Is actively underway.

However, there are many problems to be solved in an OFDMA-based femtocell-based system.

The femtocell's access method is divided into a closed network that allows only authorized users and an open network that allows all users. In the case of an open network, there is a problem of the same handover priority, but this can be easily solved by setting a handover threshold.

However, since the femtocell base station is installed in the macrocell coverage in the closed network, when the femtocell base station is installed without additional setting, the femtocell base station may not operate smoothly due to the macrocell base station interference.

On the contrary, when the macrocell terminals enter the femtocell base station region, the macrocell terminal communication is impossible due to the femtocell base station interference.

The present invention provides a femtocell base station apparatus and a self-configuration in which a femtocell can maximize its area while minimizing damage to a macrocell by minimizing self-setting to minimize interference to an adjacent macrocell or another femtocell. Provide a method.

According to one embodiment of the present invention, a femtocell base station apparatus is provided. This apparatus is a femtocell base station apparatus installed in a home located on macrocell coverage and having a separate femtocell coverage. The apparatus allocates power for setting transmission power using a macrocell preamble extracted from signals received from adjacent macrocells and femtocells. part; A preamble selector for selecting a femtocell preamble by using a correlation value between the macrocell preamble and a pre-stored femtocell preamble; And a resource allocator for allocating resources for data transmission in the femtocell in consideration of the magnitude of signal interference between the adjacent macrocell and the femtocell.

According to another embodiment of the present invention, a self setting method of a femtocell base station is provided. A method of self-configuration of a femtocell base station, the method comprising: extracting a preamble from signals received from adjacent macrocells and femtocells; Setting transmission power of the femtocell base station using the extracted macrocell preamble; Selecting a preamble of the femtocell base station by using a correlation value between the macrocell preamble and a pre-stored femtocell preamble; And allocating resources for data transmission of the femtocell base station in consideration of the amount of signal interference between the adjacent macrocell and the femtocell.

According to an embodiment of the present invention, by minimizing or using the conventional specification change, it is designed to detect the preamble of the user of the macro cell and to decode the MAP / FCH (Frame Control Header) even within the femtocell base station to prevent damage to the macro cell. At the same time, femtocells maximize their area.

At this time, the femtocell base station minimizes the interference to the macrocell terminal by setting itself in a direction to minimize the damage to the outside and to determine the environment of the surrounding macrocell and femtocell by themselves without being controlled by the macrocell base station or the outside.

Therefore, due to the installation of the femtocell base station, it is possible to solve the shadow area of the macrocell at a low price without installing the macrocell base station.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and similar drawings are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

Now, a femtocell base station apparatus and a self-configuration method according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a block diagram showing the internal configuration of a femtocell base station apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the femtocell base station apparatus 1 includes an antenna 100, a wireless signal transceiver 200, a transceiver 300, a receiver 400, a preamble extractor 500, and a power allocator 600. ), Preamble selector 700, resource allocator 800, demodulator 900, inverse frame generator 1000, decoder 1100, preamble generator 1200, modulator 1300, frame The generator 1400 and the transmitter 1500 are included.

The wireless signal transceiver 200 transmits and receives signals of a femto cell and a macro cell through the antenna 100.

The transmission / reception separator 300 separates the received signal from the antenna 100 and the signal transmitted from the transmitter 1500.

The receiver 400 receives the signals of the femtocell and macrocell separated by the transmission and reception separation unit 300.

The preamble extractor 500 extracts the preamble from the signals of the femtocell and macrocell received by the receiver 400. At this time, a signal corresponding to a femtocell and a signal corresponding to a macrocell are separated. The signal of the femtocell is transmitted to the demodulator 900, and the signals of the macrocell and femtocell are transmitted to the power allocator 600.

The power allocator 600 allocates the transmission power of the femtocell base station apparatus 1 using Equation 1 below in the initialization step. That is, the reception unit 400 determines the transmission power using the signal of the macro cell received.

Figure 112009060004766-pat00001

here,

Figure 112009060004766-pat00002
Is the received power of the signal received from the macro cell.
Figure 112009060004766-pat00003
Is path attenuation when the area radius of the femtocell base station apparatus 1 is d. G is a gain value of the transmission power of the femtocell base station apparatus 1.
Figure 112009060004766-pat00004
Is the maximum transmit power of the femtocell base station apparatus 1.

The preamble selector 700 selects the preamble after the initial power allocation is performed by the power allocator 600. In this case, the preamble may be a preamble of IEEE 802.16e. The preamble signal required for cell searching is located at the first symbol of the frame and uses a binary phase shift keying (BPSK) modulation scheme.

The preamble signal uses different subcarrier sets according to segments. In the IEEE 802.16e based OFDMA system, the preamble signal has a total of three segments. The preamble signal is allocated a subcarrier set that does not overlap each other for each segment. There are a total of 114 preambles. The 114 preamble signals are allocated 38 usable preambles for each segment.

The preamble selector 700 may use the preamble that is punctured in two or more patterns with the existing preamble while using the IEEE 802.16e based preamble. The punched preamble will be described in detail later with reference to FIG. 2.

The resource allocator 800 may configure the FCH signal to exist at different positions for each subsegment by repeating the FCH (Fundamental Channel) signal four times a small number of times. The FCH signal includes the location of the MAP signal and related information.

The resource allocator 800 allocates resources to be used for femtocell data transmission after the preamble and MAP / FCH allocation.

The demodulator 900 demodulates the signal of the femtocell from which the preamble is removed by the preamble extractor 500.

The inverse frame generator 1000 inversely frames the femtocell signal demodulated by the demodulator 900.

The decoder 1100 decodes the signal of the femtocell inversely framed by the inverse frame generator 1000.

The preamble generator 1200 generates a preamble selected by the preamble selector 700.

The modulator 1300 modulates the preamble generated by the preamble generator 1200.

The frame generator 1400 generates a frame using the preamble modulated by the modulator 1300 and the resources allocated by the resource allocator 800.

The transmitter 1500 transmits the frame generated by the frame generator 1400 to the radio signal transceiver 200 through the transceiver transceiver 300. Then, the radio signal transmission and reception unit 200 transmits to the outside through the antenna 100.

2 shows a preamble according to an embodiment of the present invention. In particular, Figure 2 (a) shows a conventional preamble. FIG. 2B shows a preamble punctured twice in pattern 1. FIG. FIG. 2C shows a preamble punctured twice in pattern 2. FIG.

Here, when two patterns are punched as shown in FIGS. 2B and 2C, one preamble may be divided into two preambles. In addition, the use of a double perforated preamble allows each segment to use a virtual segment that acts like two subsegments under each segment.

In addition, the number of preambles available for each segment also doubles. In other words, the more perforated multiples, the more subsegments and preambles can be used.

3 to 7, five embodiments of the preamble selection algorithm of the preamble selector 700 will be described. In this case, the components performing the same function in each embodiment uses the same reference numerals, and duplicate descriptions are omitted.

3 is a block diagram illustrating a detailed configuration of a preamble selector according to a first embodiment of the present invention. That is, the configuration of the first preamble selection algorithm will be described.

Referring to FIG. 3, the preamble selecting unit 700 includes a receiving module 701, a storage module 703, a correlation value calculating module 705, and a preamble selecting module 707.

The receiving module 701 receives the macro cell preamble from the power allocator 600.

The storage module 703 stores the femtocell preamble. That is, the femtocell preamble based on IEEE 802.16e is stored.

The correlation value calculating module 705 receives a signal corresponding to the k-th subcarrier of the j-th preamble of the macrocell preamble from the receiving module 701.

Figure 112009060004766-pat00005
. And the signal of the kth subcarrier of the jth preamble from the storage module 703.
Figure 112009060004766-pat00006
.

The correlation value calculation module 705

Figure 112009060004766-pat00007
Wow
Figure 112009060004766-pat00008
By using the differential correlation value using the differential vector as shown in Equation 2 below (
Figure 112009060004766-pat00009
).

Figure 112009060004766-pat00010

here,

Figure 112009060004766-pat00011
Indicates.

Figure 112009060004766-pat00012
Indicates.

In this case, K represents the number of sequences of the preamble.

The preamble selection module 707 receives the differential correlation values calculated using Equation 2 for all the preambles from the correlation value calculation module 705. The femtocell base station apparatus 1 selects the index of the preamble having the lowest correlation among the received differential correlation values as the preamble to be used.

4 is a block diagram illustrating a detailed configuration of a preamble selector according to a second embodiment of the present invention. That is, the configuration of the second preamble selection algorithm will be described.

Referring to FIG. 4, the preamble selecting unit 700 includes a receiving module 701, a storage module 703, a segment selecting module 709, a correlation value calculating module 705, and a preamble selecting module 707.

The segment selection module 709 selects a segment to be used by the femtocell base station apparatus 1. The segment selection module 709 selects the segment S having the lowest sum of the energy of the received signal of each segment as shown in Equation 3 below. In this case, the sum of the received signal energies of the segments may be obtained by accumulating one preamble or a plurality of preambles.

Figure 112009060004766-pat00013

here,

Figure 112009060004766-pat00014
Denotes a subcarrier set corresponding to the s-th segment.
Figure 112009060004766-pat00015
Denotes the k th carrier signal in the received signal.

The correlation value calculation module 705 calculates the differential correlation value between the preamble of the segment selected by the segment selection module 709 and the femtocell preamble stored in the storage module 703, not the differential correlation value for all preambles. Calculate using

5 is a block diagram illustrating a detailed configuration of a preamble selector according to a third embodiment of the present invention. That is, the configuration of the third preamble selection algorithm will be described.

Referring to FIG. 5, the preamble selecting unit 700 includes a receiving module 701, a storage module 711, a correlation value calculating module 713, and a preamble selecting module 707.

The storage module 711 stores the femtocell preambles perforated by the number of predetermined patterns described with reference to FIGS. 2B and 2C. The total number of preambles is increased by several times the number of perforated patterns compared to the number of preambles. For example, in the case of double drilling, the number of preambles for which a correlation value is to be obtained is 228.

The correlation value calculation module 713 applies the punctured femtocell preamble stored in the storage module 711 to calculate a correlation value with the j th preamble using Equation 4 below.

Figure 112009060004766-pat00016

At this time,

Figure 112009060004766-pat00017
Means the number of perforated patterns.

6 is a block diagram illustrating a detailed configuration of a preamble selector according to a fourth embodiment of the present invention. That is, the configuration of the fourth preamble selection algorithm will be described.

Referring to FIG. 6, the preamble selector 700 includes a reception module 701, a storage module 711, a segment selection module 709, a correlation value calculation module 713, and a preamble selection module 707.

The correlation value calculation module 713 calculates a correlation value between the preamble of the segment selected by the segment selection module 709 and the perforated femtocell preamble stored in the storage module 711 using Equation 4.

7 is a block diagram illustrating a detailed configuration of a preamble selector according to a fifth embodiment of the present invention. That is, the configuration of the fifth preamble selection algorithm will be described.

Referring to FIG. 7, the preamble selector 700 includes a reception module 701, a storage module 711, a subsegment selection module 715, a correlation value calculation module 713, and a preamble selection module 707. .

The subsegment selection module 715 detects energy for the virtual subsegment according to the punctured pattern for the macrocell preamble as shown in Equation 5 below. The subsegment having the lowest sum of the energy of the received signal of the subsegment is selected.

Figure 112009060004766-pat00018

here,

Figure 112009060004766-pat00019
Denotes a p-th subsegment subcarrier set.

The correlation value calculating module 713 calculates the preamble of the subsegment selected by the subsegment selection module 715 and the perforated femtocell preamble and the correlation value stored in the storage module 711 using Equation 4.

In the IEEE 802.16e system, the FCH signal is repeated four times at a predetermined position according to each segment to configure the FCH signal.

In the third, fourth, and fifth embodiments of the present invention, it is possible to select subdivision segments that are not conventional segments. In this case, the resource allocating unit 800 may configure the FCH signal so that the FCH signal is repeated at a small number of times without repeating the FCH signal four times. The location of the MAP and the reception information are included in the FCH.

8 is a block diagram showing the detailed configuration of a resource allocation unit according to an embodiment of the present invention.

Referring to FIG. 8, the resource allocating unit 800 includes a measurement module 801 and a subchannel selection module 803.

The measurement module 801 measures an interference to noise ratio (hereinafter, referred to as 'INR') in the process of selecting the preamble by the preamble selector 700. At this time, the power of the noise can be known by measuring the power of the received signal of the guard band of the OFDM symbol. The magnitude of interference between the macrocell and the femtocell can be known by measuring the received signal magnitude of the macrocell preamble.

The subchannel selection module 803 determines the subchannel technique used by the femtocell according to the INR value measured by the measurement module 801 in the initialization step. In other words, the lower the INR, the greater the distance from the macrocell, so the effect of noise is greater than that of interference. The femtocell base station apparatus 1 in such a region can show a higher data rate by transmitting with high power using less frequency resources.

The subchannel selection module 803 uses subchannels in the form of full usage of subchannels (FUSC) and partial usage of subchannels (PUSC) based on the existing IEEE 802.16e, and at the same time provides a higher frequency reuse rate according to each subsegment selection. Branches can use a new type of PUSC. As a method of increasing the reuse rate of a conventional PUSC subchannel, it may have various forms.

In this case, the interference between femtocells using different sub-segments is prevented by using only 1 / N resources orthogonal to the PUSCH-type subchannel resources in the time axis or the frequency axis.

9 shows a configuration in which subchannel resources are divided according to an embodiment of the present invention. In particular, FIG. 9A illustrates a subchannel configuration, FIG. 9B illustrates a configuration in which subchannel resources are divided on a frequency axis, and FIG. 9C illustrates subchannel resources on a time axis. The configuration is shown.

9 (b) and 9 (c), when the frequency reuse rate is N, the subchannel resources on the frequency axis and the time axis are divided and used. That is, the subchannel selection module 803 of FIG. 8 divides the subchannel resource according to the frequency reuse rate N according to each subsegment into a frequency axis or a time axis. Here, the frequency reuse rate is N to use 1 / N of all possible frequency bands.

10 shows an example of allocating resources to a frequency axis when the frequency reuse rate is 2 according to an embodiment of the present invention.

In particular, FIG. 10 (a) shows a subchannel generation in the PUSC form of the IEEE 802.16e system. In the conventional system, one subcarrier is selected from a total of 24 subcarrier sets to form a new 24 subcarrier sets. A pair of 24 subcarrier sets spanning two OFDM symbols form one subchannel.

FIG. 10B illustrates an example in which the subchannel is divided into 1/2 on the frequency axis. A subcarrier is selected from only 12 of the 24 subcarrier sets to form 12 subcarrier sets, and 12 subcarrier sets of 4 OFDM symbols form one subchannel.

11 to 24 show the results of simulating the embodiment of the present invention. Here, the femtocell base station apparatus 1 sets an inside of a building located in an area of a macro radius of a wide radius existing outdoors as femtocell coverage for a few subscribers.

First, FIGS. 11 to 16 show detection performance of a macrocell preamble within femtocell coverage.

First, FIG. 11 shows detection performance of a macrocell preamble within femtocell coverage when using a preamble to which only power allocation is applied.

Referring to FIG. 11, outside the building, the probability of failure of detecting the macrocell preamble is increased.

Figure 112009060004766-pat00020
It is as follows. In buildings, the probability of failure to detect macrocell preamble
Figure 112009060004766-pat00021
That's it. And the probability of failure to detect macrocell preamble at the interior and exterior boundaries of the building
Figure 112009060004766-pat00022
More than
Figure 112009060004766-pat00023
Some areas of phosphorus appear.

As such, in case of only power allocation, it can be seen that the probability of detection failure of the macrocell preamble within the femtocell coverage is very high.

12 illustrates the detection performance of the macrocell preamble within femtocell coverage when the preamble selection algorithm according to the first embodiment of the present invention is used. That is, this corresponds to the case where the first preamble selection algorithm of the preamble selector 700 of FIG. 3 is used.

Referring to FIG. 12, the probability of failure in detecting a macrocell preamble outside a building is increased.

Figure 112009060004766-pat00024
It is as follows. In buildings, the probability of failure to detect macrocell preamble
Figure 112009060004766-pat00025
The probability of failure of detection of the abnormal region and the macrocell preamble
Figure 112009060004766-pat00026
More than
Figure 112009060004766-pat00027
The following areas appear evenly. At this time, the detection failure probability of the macrocell preamble
Figure 112009060004766-pat00028
More abnormal areas appear.

FIG. 13 illustrates detection performance of a macrocell preamble within femtocell coverage when the preamble selection algorithm according to the second embodiment of the present invention is used. That is, the second preamble selection algorithm of the preamble selector 700 of FIG. 4 is used.

Referring to FIG. 13, the probability of failure of detecting the macrocell preamble is increased outside the building.

Figure 112009060004766-pat00029
It is as follows. In buildings, the probability of failure to detect macrocell preamble
Figure 112009060004766-pat00030
The probability of failure of detection of the abnormal region and the macrocell preamble
Figure 112009060004766-pat00031
More than
Figure 112009060004766-pat00032
The following areas appear similar. However, the probability of detection failure of the macrocell preamble
Figure 112009060004766-pat00033
More than
Figure 112009060004766-pat00034
A few more areas appear below.

14 illustrates the detection performance of the macrocell preamble within femtocell coverage when the preamble selection algorithm according to the third embodiment of the present invention is used. That is, the third preamble selection algorithm of the preamble selector 700 of FIG. 5 is used.

Referring to FIG. 14, the probability of failure in detecting a macrocell preamble outside a building is increased.

Figure 112009060004766-pat00035
It is as follows. In buildings, the probability of failure to detect macrocell preamble
Figure 112009060004766-pat00036
More than
Figure 112009060004766-pat00037
The area below is when the probability of failure of detecting the macrocell preamble
Figure 112009060004766-pat00038
Much more than the above area. And the probability of detection failure of the macrocell preamble
Figure 112009060004766-pat00039
Some of the following areas also appear.

FIG. 15 shows detection performance of a macrocell preamble within femtocell coverage when another preamble selection algorithm is used in the fourth embodiment of the present invention. That is, the fourth preamble selection algorithm of the preamble selector 700 of FIG. 6 is used.

Referring to FIG. 15, the probability of failure in detecting a macrocell preamble outside a building is increased.

Figure 112009060004766-pat00040
It is as follows. In buildings, the probability of failure to detect macrocell preamble
Figure 112009060004766-pat00041
Abnormal region, macrocell preamble detection failure probability
Figure 112009060004766-pat00042
More than
Figure 112009060004766-pat00043
The following areas appear similar. And the probability of detection failure of the macrocell preamble
Figure 112009060004766-pat00044
The following areas also appear in large part.

FIG. 16 shows detection performance of a macrocell preamble within femtocell coverage when the preamble selector selects a preamble according to the fifth embodiment of the present invention. That is, this corresponds to the case where the fifth preamble selection algorithm of the preamble selector 700 of FIG. 6 is used.

Referring to FIG. 16, outside the building, the probability of failure of detecting the macrocell preamble is increased.

Figure 112009060004766-pat00045
It is as follows. In buildings, the probability of failure to detect macrocell preamble
Figure 112009060004766-pat00046
Most of the area is below, and the probability of the detection failure of the macrocell preamble is
Figure 112009060004766-pat00047
More than
Figure 112009060004766-pat00048
The following areas are partially shown. Probability of detection failure of macrocell preamble
Figure 112009060004766-pat00049
The abnormal region does not appear at all.

As described above, referring to FIGS. 12 to 16, the detection failure probability of the macrocell preamble in the building increases as the fifth embodiment to the fifth embodiment of the present invention.

Figure 112009060004766-pat00050
It can be seen that more regions appearing below. That is, since the detection failure probability of the macrocell preamble is decreasing, it can be confirmed that the detection performance of the macrocell preamble is increased.

Next, FIGS. 17 to 22 show detection performance of a femtocell preamble within femtocell coverage. In this case, one thick square represents one femtocell coverage.

First, FIG. 17 illustrates detection performance of a femtocell preamble within femtocell coverage when using a preamble to which only power allocation is applied.

Referring to FIG. 17, all of the femtocell preamble detection failure probabilities within the femtocell coverage are increased.

Figure 112009060004766-pat00051
It is an area below. Outside of femtocell coverage, all of the femtocell preamble detection
Figure 112009060004766-pat00052
An abnormal area appears. In other words, even if the power allocation alone, the femtocell preamble detection probability is high in the femtocell coverage.

18 illustrates detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the first embodiment of the present invention is used. That is, this corresponds to the case where the first preamble selection algorithm of the preamble selector 700 of FIG. 3 is used.

Referring to FIG. 18, all of the femtocell preamble detection failure probabilities are increased within femtocell coverage.

Figure 112009060004766-pat00053
It is an area below. Outside of femtocell coverage, all of the femtocell preamble detection
Figure 112009060004766-pat00054
An abnormal area appears. That is, it appears similar to FIG.

19 illustrates detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the second embodiment of the present invention is used. That is, the second preamble selection algorithm of the preamble selector 700 of FIG. 4 is used.

Referring to FIG. 19, all of the femtocell preamble detection failure probabilities are increased within femtocell coverage.

Figure 112009060004766-pat00055
It is an area below. Outside femtocell coverage, the probability of detection failure of a femtocell preamble is almost
Figure 112009060004766-pat00056
An abnormal area appears. However, the probability of detection failure of femtocell preamble
Figure 112009060004766-pat00057
More than
Figure 112009060004766-pat00058
Some areas below are shown. In addition, there is a fine but undetectable probability of femtocell preamble
Figure 112009060004766-pat00059
The following area also appears.

20 illustrates detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the third embodiment of the present invention is used. That is, the third preamble selection algorithm of the preamble selector 700 of FIG. 5 is used.

Referring to FIG. 20, all of the femtocell preamble detection failure probabilities are increased within femtocell coverage.

Figure 112009060004766-pat00060
It is an area below. Outside femtocell coverage, the probability of detection failure of a femtocell preamble
Figure 112009060004766-pat00061
In most cases, the femtocell preamble fails to detect.
Figure 112009060004766-pat00062
More than
Figure 112009060004766-pat00063
The area | region below is shown a considerable part. In addition, the detection failure probability of the femtocell preamble
Figure 112009060004766-pat00064
Some of the following areas also appear.

21 illustrates detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the fourth embodiment of the present invention is used. That is, the fourth preamble selection algorithm of the preamble selector 700 of FIG. 6 is used.

Referring to FIG. 21, all of the femtocell preamble detection failure probabilities are increased within femtocell coverage.

Figure 112009060004766-pat00065
It is an area below. Outside femtocell coverage, the probability of detection failure of a femtocell preamble is almost
Figure 112009060004766-pat00066
An abnormal area appears. However, the probability of detection failure of femtocell preamble
Figure 112009060004766-pat00067
More than
Figure 112009060004766-pat00068
The area | region below is shown a considerable part. In addition, the detection failure probability of the femtocell preamble
Figure 112009060004766-pat00069
Some of the following areas also appear.

FIG. 22 illustrates detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the fifth embodiment of the present invention is used. That is, it corresponds to the case where the fifth preamble selection algorithm of the preamble selector 700 of FIG. 7 is used.

Referring to FIG. 22, all of the femtocell preamble detection failure probabilities are increased within femtocell coverage.

Figure 112009060004766-pat00070
It is an area below. Outside femtocell coverage, the probability of detection failure of a femtocell preamble
Figure 112009060004766-pat00071
Abnormal region and detection failure probability
Figure 112009060004766-pat00072
More than
Figure 112009060004766-pat00073
The following areas appear similar.

As described above, it can be seen that the detection probability of the femtocell preamble outside the femtocell increases from the first embodiment to the fifth embodiment.

FIG. 23 is a graph illustrating a data rate of a macro cell user in femtocell coverage according to an embodiment of the present invention. FIG. That is, the data transmission rate is compared between the case where the segment and the preamble are allocated using the fifth embodiment of the present invention and the power allocation only.

Referring to FIG. 23, it shows a transmission rate of a macro cell terminal in an outer region within femtocell coverage. As the femtocell base station apparatus 1 increases its distance from the macrocell, the data rate decreases.

In particular, when the fifth embodiment of the present invention is applied, the PUSC is used, and the frequency reuse rates are 2 and 4 (reuse 2 and 4), the data transmission rate is high. In addition, as the femtocell base station apparatus 1 increases its distance from the macrocell, the femtocell base station apparatus 1 exhibits the greatest data rate reduction.

In this case, when using PUSC but only power control (PC), the data rate is low.

In addition, regardless of whether or not the fifth embodiment of the present invention is applied, the data rate is the lowest when using the FUSC type subchannel.

Therefore, the femtocell base station apparatus 1 should transmit with low power when it is far from the macrocell. In this case, using a small number of subchannels of the conventional PUSC type, higher performance per subchannel is shown.

When the femtocell base station apparatus 1 uses the FUSC type subchannel, the macro cell user cannot communicate in femtocell coverage. However, when the femtocell base station apparatus 1 uses the PUSC type subchannel and applies the fifth embodiment of the present invention, the femtocell base station apparatus 1 shows better performance than the case of simply allocating power.

24 is a graph illustrating a data transmission rate of a femtocell user in femtocell coverage according to an embodiment of the present invention.

Referring to FIG. 24, as the femtocell base station apparatus 1 increases in distance from the macrocell, the data rate decreases.

In particular, whether or not the femtocell base station apparatus 1 uses the FUSC type subchannel regardless of whether the fifth embodiment of the present invention is applied, the highest transmission rate is shown. However, since the macrocell user cannot communicate in femtocell coverage, the femtocell base station apparatus 1 must use a subchannel of PUSC type.

In addition, the use of the subchannel of the PUSC type shows a higher performance than the case of only power allocation when using the fifth embodiment of the present invention.

Embodiments of the present invention are not implemented only through the above-described apparatus and / or method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiments of the present invention, a recording medium on which the program is recorded, and the like. It may be.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

1 is a block diagram showing the internal configuration of a femtocell base station apparatus according to an embodiment of the present invention.

2 shows a preamble according to an embodiment of the present invention.

3 is a block diagram illustrating a detailed configuration of a preamble selector according to a first embodiment of the present invention.

4 is a block diagram illustrating a detailed configuration of a preamble selector according to a second embodiment of the present invention.

5 is a block diagram illustrating a detailed configuration of a preamble selector according to a third embodiment of the present invention.

6 is a block diagram illustrating a detailed configuration of a preamble selector according to a fourth embodiment of the present invention.

7 is a block diagram illustrating a detailed configuration of a preamble selector according to a fifth embodiment of the present invention.

8 is a block diagram showing the detailed configuration of a resource allocation unit according to an embodiment of the present invention.

9 shows a configuration in which subchannel resources are divided according to an embodiment of the present invention.

10 shows an example of allocating resources to a frequency axis when the frequency reuse rate is 2 according to an embodiment of the present invention.

FIG. 11 shows detection performance of a macrocell preamble within femtocell coverage when using a preamble applied with power allocation only.

12 illustrates the detection performance of the macrocell preamble within femtocell coverage when the preamble selection algorithm according to the first embodiment of the present invention is used.

FIG. 13 illustrates detection performance of a macrocell preamble within femtocell coverage when the preamble selection algorithm according to the second embodiment of the present invention is used.

14 illustrates the detection performance of the macrocell preamble within femtocell coverage when the preamble selection algorithm according to the third embodiment of the present invention is used.

FIG. 15 shows detection performance of a macrocell preamble within femtocell coverage when another preamble selection algorithm is used in the fourth embodiment of the present invention.

FIG. 16 illustrates the detection performance probability of the macrocell preamble within femtocell coverage when the preamble selector selects the preamble according to the fifth embodiment of the present invention.

FIG. 17 illustrates detection performance of a femtocell preamble within femtocell coverage when using a preamble applied with power allocation only.

18 illustrates detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the first embodiment of the present invention is used.

19 illustrates detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the second embodiment of the present invention is used.

20 illustrates detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the third embodiment of the present invention is used.

21 shows detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the fourth embodiment of the present invention is used.

FIG. 22 illustrates detection performance of a femtocell preamble within femtocell coverage when the preamble selection algorithm according to the fifth embodiment of the present invention is used.

FIG. 23 is a graph illustrating a data rate of a macro cell user in femtocell coverage according to an embodiment of the present invention. FIG.

24 is a graph illustrating a data transmission rate of a femtocell user in femtocell coverage according to an embodiment of the present invention.

Claims (18)

  1. A femtocell base station apparatus installed in a home located on macrocell coverage and having a separate femtocell coverage,
    A power allocator configured to set transmission power using a macrocell preamble extracted from signals received from adjacent macrocells and femtocells;
    A preamble selector for selecting a femtocell preamble by using a correlation value between the macrocell preamble and a pre-stored femtocell preamble; And
    Resource allocation unit for allocating resources for data transmission in the femtocell in consideration of the magnitude of the signal interference between the adjacent macro cell and femtocell
    Femtocell base station device comprising a.
  2. The method of claim 1,
    The preamble selector,
    A correlation value calculation module for calculating differential correlation values between the macrocell preamble and the pre-stored femtocell preamble; And
    Preamble selection module for selecting a femtocell preamble having the lowest differential correlation value among the differential correlation values
    Femtocell base station device comprising a.
  3. 3. The method of claim 2,
    The preamble selector,
    Segment selection module for selecting the segment with the lowest energy sum of the received signal for each segment among the signals received from the adjacent macrocell,
    The correlation value calculation module,
    The femtocell base station apparatus for calculating a differential correlation value between the preamble of the segment selected by the segment selection module and the preamble of the pre-stored femtocell.
  4. 3. The method of claim 2,
    The preamble selector,
    Further comprising a storage module for storing the femtocell preamble perforated by the number of the predetermined pattern,
    The correlation value calculation module,
    And a differential correlation value between the macrocell preamble and the perforated femtocell preamble stored in the storage module in consideration of the number of the predefined patterns.
  5. 3. The method of claim 2,
    The preamble selector,
    Segment selection module for selecting the segment with the lowest energy sum of the received signal for each segment among the signals received from the adjacent macrocell,
    The correlation value calculation module,
    The femtocell base station apparatus for calculating the differential correlation values between the preamble of the segment selected by the segment selection module and the punctured femtocell preamble.
  6. The method of claim 1,
    The preamble selector,
    A storage module storing the femtocell preamble perforated by the number of predefined patterns;
    A subsegment selection module for selecting a subsegment having a lowest sum of energy for a virtual subsegment according to a punctured pattern among signals received from the adjacent macrocell;
    A correlation value calculation module for calculating a differential correlation value between the preamble of the subsegment selected by the subsegment selection module and the punctured femtocell preamble stored in the storage module in consideration of the number of the predefined patterns; And
    Preamble selection module for selecting a femtocell preamble having the lowest differential correlation value among the differential correlation values
    Femtocell base station device comprising a.
  7. The method according to any one of claims 4 to 6,
    The resource allocation unit,
    Femtocell base station apparatus configured to repeat the frame control header signal and configure the frame control header signal to exist at different positions for each subsegment.
  8. The method according to any one of claims 1 to 6,
    The resource allocation unit,
    A measurement module for measuring a noise to interference ratio by measuring a magnitude of a received signal of the macrocell preamble; And
    Subchannel selection module for determining a subchannel scheme according to the noise to interference ratio
    Femtocell base station device comprising a.
  9. 9. The method of claim 8,
    The subchannel selection module,
    A femtocell base station apparatus for allocating subchannel resources in the form of Partial Usage of Subchannels (PUSC) to use subchannel resources of 1 / reuse rate orthogonal to a time axis or a frequency axis.
  10. In the self-setting method of a femtocell base station,
    Extracting a preamble from signals received from adjacent macrocells and femtocells;
    Setting transmission power of the femtocell base station using the extracted macrocell preamble;
    Selecting a preamble of the femtocell base station by using a correlation value between the macrocell preamble and a pre-stored femtocell preamble; And
    Allocating resources for data transmission of the femtocell base station in consideration of the magnitude of signal interference between the adjacent macrocell and femtocell;
    Self setting method of the femtocell base station comprising a.
  11. The method of claim 10,
    Wherein the selecting comprises:
    Calculating a differential correlation value between the macrocell preamble and the pre-stored femtocell preamble; And
    Selecting a femtocell preamble having the lowest differential correlation value among the differential correlation values
    Self setting method of the femtocell base station comprising a.
  12. 12. The method of claim 11,
    Selecting a segment having the lowest energy sum of the received signal of each segment among the signals received from the adjacent macrocells;
    Wherein the calculating step comprises:
    And calculating a differential correlation value between the preamble of the selected segment and the preamble of the pre-stored femtocell.
  13. 12. The method of claim 11,
    Wherein the calculating step comprises:
    And calculating the differential correlation value between the macrocell preamble and the pre-stored femtocell preambles perforated by the number of the predetermined patterns in consideration of the number of the predetermined patterns.
  14. 14. The method of claim 13,
    Selecting a segment having the lowest energy sum of the received signal of each segment among the signals received from the adjacent macrocells;
    Wherein the calculating step comprises:
    And calculating the differential correlation value between the preamble of the selected segment and the pre-stored pre-stored femtocell preambles by the number of the predetermined patterns.
  15. The method of claim 10,
    Wherein the selecting comprises:
    Selecting a subsegment having a lowest sum of energy for a virtual subsegment according to a punctured pattern among signals received from the adjacent macrocell;
    Calculating a differential correlation value between the preamble of the selected subsegment and the pre-stored pre-stored femtocell preamble by the number of predefined patterns in consideration of the number of the predefined patterns; And
    Selecting a femtocell preamble having the lowest differential correlation value among the differential correlation values
    Self setting method of the femtocell base station comprising a.
  16. The method according to any one of claims 13 to 15,
    Allocating the resource,
    Self-configuring method of the femtocell base station to configure the frame control header signal to repeat the frame control header signal to be present in different positions for each subsegment.
  17. The method according to any one of claims 10 to 15,
    Allocating the resource,
    Calculating a noise-to-interference ratio by measuring a received signal size of the macrocell preamble; And
    Determining a subchannel scheme according to the noise-to-interference ratio
    Self setting method of the femtocell base station comprising a.
  18. 18. The method of claim 17,
    The determining step,
    A self-configuration method of a femtocell base station for allocating subchannel resources in the form of Partial Usage of Subchannels (PUSC) to use 1 / reuse rate subchannel resources orthogonal to a time axis or a frequency axis.
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