FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
“INTERFERENCE MITIGATION APPARATUS
AND INTERFERENCE MITIGATION METHOD
FOR HOME NETWORK TRANSMISSION LINE,
AND COMMUNICATION SYSTEM USING
SAME”
KT CORPORATION, of 90 Buljeong-ro, Bundang-gu,
Seongnam-si, Gyeonggi-do 463-711, Republic of Korea
The following specification particularly describes the invention and the
manner in which it is to be performed.
1
【DESCRIPTION】
【Invention Title】
INTERFERENCE MITIGATION APPARATUS AND INTERFERENCE
MITIGATION METHOD FOR HOME NETWORK TRANSMISSION LINE, AND
COMMUNICATION 5 SYSTEM USING SAME
【Technical Field】
The present disclosure relates to an interference mitigation apparatus and an
interference mitigation method for home network transmission line and communication
system using same.
10 【Background Art】
Typically, based on a very high bit rate digital subscriber line (VDSL)
technology, an uplink/downlink frequency division multiplexing (FDM) scheme has
been used for indoor telephone lines to achieve a transmission speed of up to about
100Mbps by applying a maximum of about 30MHz frequency band.
15 In the related art, a bonding technology has been used to provide a speed of a
gigabit per second exceeding about 100 Mbps. However, such a bonding technology
requires at least two or more pairs. Accordingly, it has been difficult to achieve a
speed of up to 200Mbps without increasing the number of pairs.
In order to provide gigabit Internet access to a typical environment
20 implemented with VDSL according to the related art, it is required to replace all
existing VDSL systems with new systems or to modify the typical environment to
FTTH (Fiber to the home). Such replacement and modification requires excessive cost.
It may be possible to archive a same goal by implementing a system with
2
FTTH-G (G.hn). Such FTTH-G provides a speed of about 100 Mbps or more and
requires a comparatively lower cost. However, in this case, it demands a method for
mitigating interference in a wire bundle environment where interference noise is
generated in a subscriber aggregation area.
The above information disclosed in this Background section 5 is only to enhance
the understanding of the background of the disclosure and therefore it may contain
information that does not form the prior art that is already known in this country to a
person of ordinary skill in the art.
【DISCLOSURE】
10 【Technical Problem】
Embodiments of the present disclosure have been made in an effort to propose
an interference mitigation apparatus and an interference mitigation method for home
network transmission line and communication system using same.
【Technical Solution】
15 According to an embodiment of the present disclosure, a method may be
provided for mitigating, by an interference mitigation apparatus, interference on a home
network transmission line. The method includes pairing domain masters with relay
terminals by a signal having a unique frequency, grouping the domain masters,
achieving Tx/Rx synchronization between the domain masters and the relay terminals,
20 and controlling the domain masters and the relay terminals to transmit/receive data
according to the Tx/Rx synchronization. The domain masters of the same groups may
be controlled not to simultaneously transmit/receive data.
The pairing may include transmitting, by the domain masters, a pairing pulse
3
signal pre-allocated to each port to the relay terminals, and receiving, by the domain
master, the pairing pulse signal including information about the relay terminals and
selecting the relay terminal to be paired for each domain master.
The grouping of the domain masters may include grouping the domain masters
causing interference by using status information 5 of channels.
The status information of the channels may include information estimated by
comparing test signals transmitted/received between the domain master and the relay
terminal, which are paired.
The method may further include, between the pairing and the grouping of the
10 domain masters, estimating channels by comparing test signals transmitted/received
between the domain masters and the relay terminals which are paired. The estimating
of the channels may include instructing the domain masters to transmit a PROBE frame
for channel estimation as a test signal, receiving the PROBE frame from the relay
terminals paired with the domain masters, and estimating channels by comparing the
15 received PROBE frame with a predetermined PROBE frame.
The performing may include achieving the Tx/Rx synchronization by varying a
ratio of a downlink and an uplink according to an amount of data.
The performing Tx/Rx synchronization may further include providing a MAC
cycle synchronization signal by varying the ratio of the downlink and the uplink
20 according to an amount of data being queued, when bandwidths and ratios of a
downlink and an uplink are different.
According to another embodiment of the present disclosure, an apparatus for
interference mitigation includes a pairing unit configured to pair domain masters with
relay terminals by transmitting/receiving a signal having a unique frequency, and a
4
control unit configured to group the domain masters using status information of
channels and to control the grouped domain masters to transmit/receive data.
The control unit may include a grouping unit configured to group the domain
masters causing interference and a synchronizing unit configured to perform Tx/Rx
synchronization between the domain master and the relay terminal, 5 which are paired.
The control unit may control the domain masters and the relay terminals to
transmit/receive data according to the Tx/Rx synchronization and control the grouped
domain masters not to simultaneously transmit/receive data.
The grouping unit may group the domain masters causing interference by using
10 the status information of the channels. The status information of the channels may
include information that is estimated by comparing test signals transmitted/received
between the domain masters and the relay terminals, which are paired.
The apparatus may further include a channel estimation unit configured to
estimate channels by comparing test signals transmitted/received between the domain
15 masters and the relay terminals, which are paired.
The channel estimation unit may include a comparing unit that
transmits/receives a PROBE frame between the domain masters and the relay terminals,
which are paired, and compares the PROBE frame received by the domain masters with
a predetermined PROBE frame.
20 When bandwidths and ratios of the downlink and the uplink are different
between the domain masters and the relay terminals, which are paired, the
synchronizing unit may perform Tx/Rx synchronization by varying the ratio of the
downlink and the uplink according to an amount of data being queued and by providing
a synchronization signal such as a MAC cycle.
5
According to yet another embodiment of the present disclosure, a
communication system includes one or more relay terminals paired with domain
masters and connected to the paired domain masters via transmission lines, an
interference mitigation apparatus that controls registering the relay terminals paired with
the domain masters and synchronizing the domain masters so as to 5 transmit/receive data,
and a server that calculates interference data of channels based on a channel status for
each port and provides the calculated the interference data to the interference mitigation
apparatus so as to synchronize the domain masters.
The interference mitigation apparatus may group the domain masters based on
10 the interference data such that the domain masters are not affected by interference.
The interference mitigation apparatus may control performing Tx/Rx
synchronization of the grouped domain masters and allowing the grouped domain
masters to transmit data to and to receive data from the relay terminals according to the
Tx/Rx synchronization. The interference mitigation apparatus may group the domain
15 masters causing interference by using channel status information. The channel status
information may include information that estimated by comparing test signals
transmitted/received between the domain master and the relay terminal that are paired.
【Advantageous Effects】
According to at least one embodiment of the present disclosure, interferences in
20 a transmission line may be minimized by pairing domain masters and relay terminals
through the pairing pulse signal selecting domain maters having comparatively large
interferences based on a result of estimating channels, grouping the selected domain
maters, and transmitting and receiving through the grouped domain masters.
In addition, according to at least one embodiment of the present disclosure,
6
interference on a transmission line may be minimized by controlling domain masters
and relay terminals to transmit and receive data according to Tx/Rx synchronization and
by controlling domain masters belonging to the same group not to transmit and receive
data at the same time.
【Description 5 of the Drawings】
FIG. 1 is a schematic block diagram of a communication system for relaying a
home network signal according to an exemplary embodiment of the present disclosure.
FIG. 2 is a schematic block diagram of a configuration of an interference
mitigation apparatus according to an exemplary embodiment of the present disclosure.
10 FIG. 3 is a diagram for describing an operation for pairing by transmitting and
receiving pairing pulse signals each having a unique frequency.
FIG. 4 is a diagram for describing an operation of grouped domain masters for
transmitting and receiving data according to Tx/Rx synchronization.
FIG. 5 is a flowchart illustrating a method for mitigating interference according
15 to another exemplary embodiment of the present disclosure.
FIG. 6 is a flowchart illustrating a process of estimating channels to mitigate
interference in a communication system.
【Mode for Invention】
In the following detailed description, only certain exemplary embodiments of
20 the present disclosure have been shown and described, simply by way of illustration.
As those skilled in the art would realize, the described embodiments may be modified in
various different ways, all without departing from the spirit or scope of the present
disclosure. Accordingly, the drawings and description are to be regarded as illustrative
in nature and not restrictive, and like reference numerals designate like elements
7
throughout the specification.
Throughout the specification, unless explicitly described to the contrary, the
word "comprise" and variations such as "comprises" or "comprising" will be understood
to imply the inclusion of stated elements but not the exclusion of any other elements.
In addition, the terms "-er", "-or" and "module" described in the 5 specification mean
units for processing at least one function and operation and can be implemented by
hardware components or software components and combinations thereof.
Hereinafter, referring to FIGS. 1 to 6, an interference mitigation apparatus and
an interference mitigation method for home network transmission line, and
10 communication system using the same are described in detail.
FIG. 1 is a schematic block diagram of a communication system for relaying a
home network signal according to an exemplary embodiment of the present disclosure.
In this case, the communication system is schematically illustrated with constituent
elements necessary to describe the exemplary embodiment of the present disclosure.
15 Embodiments of the present disclosure are not limited thereto..
Referring to FIG. 1, the communication system for relaying a home network
signal according to the current exemplary embodiment of the present disclosure
includes a server 10, a home network signal relay apparatus 30, and a plurality of relay
terminals 40.
20 In accordance with at least one embodiment, the communication system for
relaying a home network signal includes an access network and a home network. The
access network relays a signal and is also referred to as an access area. The home
network is referred to as a home area. Herein, the access network relays a signal of
Internet network to a plurality of home areas. The home network receives a signal
8
related from the access network and provides the relayed signal to a service provider’s
terminal and a home user’s terminal (not shown).
In this case, an optical cable may be used to connect the server 10 to the access
area, and the home network signal relay apparatus 30 may be provided between the
access area and the home area. In the home area, a service is provided 5 by transmitting
a signal from the home network signal relay apparatus 30 to a relay terminal 40 or an
end point (EP) through various kinds of copper wire bundle cables that are connected to
each subscriber.
The server 10 is connected to the home network signal relay apparatus 30 via
10 the optical cable through Internet or FTTx (Fiber to the x) 20. The server 10 is
connected to the home network signal relay apparatus 30 through an interface module
32 for interfacing an existing network including a passive optical network (PON) or
L2/L3 switches. The server 10 performs service policy management and network
management.
15 In accordance with at least one embodiment, the server 10 may receive an
estimated channel status, calculate interference data of a channel based on the received
channel status, and provide the interference data calculated to synchronize domain
masters 34a to 34x to one of the home network signal relay apparatus 30 and an
interference mitigation apparatus 100 (referring to FIG. 2).
20 According to the embodiment of the present disclosure, the home network
signal relay apparatus 30 may include the interference mitigation apparatus 100. In
this case, the interference mitigation apparatus 100 includes a control unit that registers
the relay terminals paired with the domain masters, uses a test signal to estimate a
channel status for each port, and synchronizes the domain masters to transmit and
9
receive data.
The domain masters 34a to 34x are respectively paired with one or more relay
terminals 40a to 40x. The domain masters 34a to 34x may be connected to the relay
terminals 40a to 40x via one or more transmission lines S1 and S2.
A configuration of the interference mitigation apparatus 5 100 will now be
described in detail with reference to FIG. 2.
FIG. 2 is a schematic block diagram illustrating an interference mitigation
apparatus according to an exemplary embodiment of the present disclosure. In FIG. 2,
the interference mitigation apparatus 100 is schematically illustrated to constituent
10 elements necessary to describe the exemplary embodiment of the present disclosure.
The embodiments of the present disclosure are not limited thereto..
Referring to FIG. 2, the interference mitigation apparatus 100 includes a pairing
unit 110, a channel measuring unit 120, and a control unit 130.
The pairing unit 110 pairs the domain masters 34a to 34x with the relay
15 terminals 40a to 40x using pairing pulse signals each having a unique frequency. In
order to pair, the pairing unit 110 controls the domain masters 34a to 34x and the relay
terminals 40a to 40x to transmit and receive the pairing pulse signals which are preallocated
to each port.
FIG. 3 is a diagram for describing an operation for pairing by transmitting and
20 receiving pairing pulse signals each having unique frequency.
Referring to FIG. 3, the domain masters 34a to 34g transmit the pairing pulse
signals that are pre-allocated to each port to the relay terminals 40a to 40g. In this case,
the pairing pulse signal may leak into an adjacent channel via crosstalk X.
After receiving the pairing pulse signals from the domain master 34g, the relay
10
terminals 40f and 40g identify frequencies and transmit the same pairing pulse signals
as those of the corresponding frequencies to the domain master 34g. Even in this case,
the pairing pulse signal transmitted by the relay terminal 40f may also leak into the
adjacent channel via crosstalk X.
The domain master 34g may receive the pairing pulse signals 5 from the relay
terminals 40f and 40g and may select one that has high signal strength. Information
about the relay terminals, such as a media access control (MAC) address, may be
included in the pairing pulse signals that are received from the relay terminals 40f and
40g.
10 In FIG. 3, the domain master 34g does not receive the pairing pulse signal
transmitted by the relay terminal 40f since the frequency thereof is not the frequency
pre-allocated to the corresponding port. The domain master 34g selects the relay
terminal 40g and set up paring with the selected relay terminal 40g.
The channel measuring unit 120 estimates a status of the corresponding channel
15 by using test signals transmitted/received between the domain masters and the relay
terminals. In this case, the channel measuring unit 120 may, as shown in FIG. 3,
estimate the channel status between the domain master 34g and the relay terminal 40g
that are paired.
The channel measuring unit 120 instructs the relay terminal 40g paired with the
20 domain master 34g to transmit/receive a PROBE frame for channel estimation as the
test signal, and the domain master 34g receives the PROBE frame from the paired relay
terminal 40g. In this case, the domain master 34g and the relay terminal 40g know the
PROBE frame for channel estimation in advance.
Herein, in accordance with at least one embodiment, the channel measuring unit
11
120 includes a comparing unit 122 that transmits/receives the PROBE frame between
the domain master and the relay terminal, which are paired, and compares the PROBE
frame received by the domain master with a predetermined PROBE frame. The
channel measuring unit 120 estimates a channel status by comparing the PROBE frame
received by the domain master via the comparing unit 122 5 with the predetermined
PROBE frame.
The control unit 130 groups the domain masters of the channels having much
interference using status information of the channels that are estimated by the channel
measuring unit 120. The control unit 130 controls the grouped domain maters to
10 transmit/receive data.
In the interference mitigation apparatus 100 according to the embodiment of the
present disclosure, the channel measuring unit 120 may measure status information of
the transmission line , and the control unit 130 may determine the domain masters with
much interference based on the measured status information, group the determined
15 domain maters into smal groups to transmit/receive data.
In accordance with at least one embodiment, the control unit 130 includes a
grouping unit 132 and a synchronizing unit 134.
When transmitting data, the grouping unit 132 groups the domain masters that
cause interference. In this case, in order to minimize influence of interference when
20 the domain masters transmit data, the grouping unit 132 identifies the domain masters
that cause interference with respect to each other and divides them into small groups.
The grouping unit 132 may group the domain masters with much interference,
using the channel status information. Herein, the channel status information includes
information that is estimated by comparing the test signals transmitted/received between
12
the domain master and the relay terminal that are paired.
The synchronizing unit 134 may achieve Tx/Rx synchronization for data
transmission between the domain master and the relay terminal that are paired. Or, the
synchronizing unit 134 may achieve Tx/Rx synchronization between the grouped
domain masters or between the 5 grouped groups.
In this case, the synchronizing unit 134 may achieve the Tx/Rx synchronization
by varying a ratio of a downlink and an uplink depending on an amount of data
transmitted/received between the domain master and the relay terminal. When
bandwidths and ratios of the downlink and the uplink are different between the domain
10 master and the relay terminal that are paired, the synchronizing unit 134 may vary the
ratio of the downlink and the uplink depending on an amount of data being queued, and
the synchronizing unit 134 may provide a synchronization signal such as a MAC cycle
to achieve Tx/Rx synchronization.
FIG. 4 is a diagram for describing grouped domain masters transmitting and
15 receiving data according to Tx/Rx synchronization. The following flowcharts will be
described using the same reference numerals in conjunction with the configurations of
FIG. 1 to FIG. 2.
Referring to FIG. 4, domain masters 34a, 34b, and 34c are grouped as a first
group G1, and domain masters 34d and 34e are grouped as a second group G2. In this
20 case, the domain masters of the same groups may have much interference therebetween.
The first domain master 34a, the second domain master 34b, and the third
domain master 34c have interference therebetween, and the fourth domain master 34d
and the fifth domain master 34e have interference therebetween.
Since the first domain master 34a, the second domain master 34b, and the third
13
domain master 34c of the first group G1 are grouped in the same group, they cannot
simultaneously transmit/receive data within the same cycle, but they may
simultaneously transmit data to and receive data from the fourth domain master 34d of
the second group G2.
That is, when the first domain master 34a transmits/receives 5 data, the second
domain master 34b or the third domain master 34c may not transmit/receive data, and
the fourth domain master 34d may transmit/receive data.
In order to alleviate interference, the interference mitigation apparatus 100
controls the domain masters to be synchronized with a MAC cycle in order to
10 simultaneously transmit/receive data at a point where the MAC cycle begins.
In this case, the synchronizing unit 134 may, depending on an amount of data
transmitted/received between the domain master and the relay terminal or bandwidths or
ratios of a downlink and an uplink, may vary the ratio of the downlink and the uplink,
and may provide a MAC cycle synchronization signal to achieve Tx/Rx synchronization.
15 That is, when bandwidths and ratios of the downlink and the uplink have
different since each user has a different service plan and thus has a different amount of
data transmitted/received, the interference mitigation apparatus 100 vary the ratio of the
downlink and the uplink according to an amount of data queued in the interface module
32 and may provide the varied ratio and the MAC cycle synchronization signal to the
20 domain masters.
FIG. 4 illustrates that when the MAC cycle synchronization signal has a cycle
of T, the domain masters are controlled to transmit data by changing the ratio of the
downlink and the uplink to a1 and b1, a2 and b2, and a3 and b3, depending on amounts
of data of the domain masters within the cycle T. In this case, the domain masters
14
internally include a buffer and may enhance data efficiency according to a TDM scheme.
A process of an interference mitigation apparatus 100 for mitigating
interference on a home network transmission line will now be described in detail with
reference to FIG. 5.
FIG. 5 is a flowchart illustrating a method for mitigating interference 5 according
to another exemplary embodiment of the present disclosure. The following flowchart
will be described using the same reference numerals in conjunction with the
configurations of FIG. 1 to FIG. 2.
Referring to FIG. 5, in the interference mitigation apparatus 100, a pairing unit
10 110 pairs domain masters with relay terminals by a pairing pulse signal with a unique
frequency (S100).
The interference mitigation apparatus 100 estimates channels by comparing test
signals transmitted/received between the domain masters and relay terminals that are
paired, and the domain masters causing interference are grouped using estimated
15 channel information (S110 and S120).
The interference mitigation apparatus 100 achieves Tx/Rx synchronization
between the domain master and the relay terminal, which are paired, and controls the
domain masters and the relay terminals to transmit/receive data according to the Tx/Rx
synchronization (S140). In this case, the interference mitigation apparatus 100
20 controls the domain masters of the same groups not to simultaneously transmit data
according to the grouping.
A process of a communication system for relaying a home network signal
mitigates interference by using an interference mitigation apparatus 100 will now be
described in detail.
15
FIG. 6 is a flowchart illustrating a process of estimating channels to mitigate
interference in a communication system. The following flowchart will be described
using the same reference numerals in conjunction with the configurations of FIG. 1 to
FIG. 2.
Referring to FIG. 6, domain masters 34 and relay terminals 5 40 are paired, the
paired devices are registered, and the results are reported to a server 10 via an
interference mitigation apparatus 100 (S200 to S206).
When the server 10 requests to estimation of channels between the domain
masters and the relay terminals, which are paired, the interference mitigation apparatus
10 100 reports channel estimation results of the domain masters and the relay terminals,
which are paired, to the server 10 (S208 to S216).
In addition, the server 10 uses the channel estimation results to calculate
interference data and provides the calculated interference data (S218 and S220).
The interference mitigation apparatus 100 uses the interference data provided
15 by the server 10 to group the domain masters, and the interference mitigation apparatus
100 synchronizes the domain masters according to a service policy (S222 to S226).
Accordingly, when transmitting/receiving data, the domain masters
transmit/receive data according to Tx/Rx synchronization achieved by the interference
mitigation apparatus 100, and the domain maters transmit/receive data according to the
20 grouping performed by the interference mitigation apparatus 100 (S228).
As described, the domain masters transmit/receive data according to the Tx/Rx
synchronization achieved by the synchronizing unit 134, and the domain masters
grouped in the same group do not simultaneously transmit/receive data since there is
much interference on transmission lines. Accordingly, interference associated with
16
data transmission/reception between the adjacent devices can be minimized.
As described, in accordance with at least one embodiment, the interference
mitigation apparatus pairs the domain masters and the relay terminals by the pairing
pulse signal, groups the domain masters with much interference based on a result of
estimating the channel, and controls the grouped domain maters to 5 transmit/receive data.
Therefore, interference on the transmission lines can be minimized.
In addition, the interference mitigation apparatus may i) control transmitting
and receiving data according to the Tx/Rx synchronization achieved by the domain
masters and the relay terminal and ii) control the domain masters belonging to the same
10 groups not to simultaneously transmit/receive data. Accordingly, interference on the
transmission lines can be minimized.
The foregoing exemplary embodiments of the present disclosure are not
implemented only by an apparatus and a method, and therefore may be realized by
programs realizing functions corresponding to the configuration of the exemplary
15 embodiment of the present disclosure or recording media on which the programs are
recorded. Such recording media may be executed in a user terminal as well as a server.
While this disclosure has been described in connection with what is presently
considered to be practical exemplary embodiments, it is to be understood that the
disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended
20 to cover various modifications and equivalent arrangements included within the spirit
and scope of the appended claims.
17
【CLAIMS】
【Claim 1】
A method for mitigating, by an interference mitigation apparatus, interference
on a home network transmission line, the method comprising:
pairing domain masters with relay terminals by a signal 5 having a unique
frequency;
grouping the domain masters;
performing Tx/Rx synchronization between the domain masters and the relay
terminals; and
10 controlling the domain masters and the relay terminals to transmit and receive
data according to the Tx/Rx synchronization,
wherein the controlling comprises controlling the domain masters of a same
groups not to simultaneously transmit/receive data.
15 【Claim 2】
The method of claim 1, wherein the pairing includes
transmitting, by the domain masters, a pairing pulse signal pre-allocated to each
port to the relay terminals, and
receiving, by the domain master, the pairing pulse signal including information
20 about the relay terminals and selecting the relay terminal to be paired for each domain
master.
【Claim 3】
18
The method of claim 1, wherein the grouping of the domain masters includes
grouping the domain masters causing interference by using status information of
channels.
5 【Claim 4】
The method of claim 3, wherein the status information of the channels includes
information estimated by comparing test signals transmitted/received between the
domain master and the relay terminal, which are paired.
10 【Claim 5】
The method of claim 1, further comprising,
between the pairing and the grouping of the domain masters, estimating
channels by comparing test signals transmitted/received between the domain masters
and the relay terminals, which are paired,
15 wherein the estimating of the channels includes
instructing the domain masters to transmit a PROBE frame for channel
estimation as a test signal,
receiving the PROBE frame from the relay terminals paired with the domain
masters, and
20 estimating channels by comparing the received PROBE frame with a
predetermined PROBE frame.
【Claim 6】
19
The method of claim 1, wherein the performing the Tx/Rx synchronization
includes performing the Tx/Rx synchronization by varying a ratio of a downlink and an
uplink according to an amount of data.
5 【Claim 7】
The method of claim 6, wherein the performing the Tx/Rx synchronization
further includes
providing a media access control (MAC) cycle synchronization signal by
varying the ratio of the downlink and the uplink according to an amount of data being
10 queued, when bandwidths and ratios of a downlink and an uplink are different.
【Claim 8】
An apparatus for interference mitigation comprising:
a pairing unit configured to pair domain masters with relay terminals by
15 transmitting/receiving a signal with a unique frequency; and
a control unit configured to group the domain masters using status information
of channels and to control the grouped domain masters to transmit/receive data.
【Claim 9】
20 The apparatus of claim 8, wherein the control unit includes
a grouping unit configured to group the domain masters causing interference
and
a synchronizing unit configured to perform Tx/Rx synchronization between the
20
domain master and the relay terminal, which are paired,
wherein the control unit is configured to control the domain masters and the
relay terminals to transmit/receive data according to the Tx/Rx synchronization and to
control the grouped domain masters not to simultaneously transmit/receive data.
5
【Claim 10】
The apparatus of claim 9, wherein the grouping unit groups the domain masters
causing interference by using the status information of the channels, and
the status information of the channels includes information that is estimated by
10 comparing test signals transmitted/received between the domain masters and the relay
terminals, which are paired.
【Claim 11】
The apparatus of claim 8, further comprising
15 a channel estimation unit configured to estimate channels by comparing test
signals transmitted/received between the domain masters and the relay terminals which
are paired.
【Claim 12】
20 The apparatus of claim 11, wherein the channel estimation unit includes a
comparing unit that transmits/receives a PROBE frame between the domain masters and
the relay terminals, which are paired, and compares the PROBE frame received by the
domain masters with a predetermined PROBE frame.
21
【Claim 13】
The apparatus of claim 10, wherein, when bandwidths and ratios of the
downlink and the uplink are different between the domain masters and the relay
terminals which are paired, the synchronizing unit performs Tx/Rx 5 synchronization by
varying the ratio of the downlink and the uplink according to an amount of data being
queued and by providing a synchronization signal such as a MAC cycle.
【Claim 14】
10 A communication system comprising:
one or more relay terminals paired with domain masters and connected to the
paired domain masters via transmission lines;
an interference mitigation apparatus configured to control registering the relay
terminals paired with the domain masters and synchronizing the domain masters to
15 transmit/receive data; and
a server configured to calculate interference data of channels based on a
channel status for each port and provide the calculated the interference data to the
interference mitigation apparatus to synchronize the domain masters.
20 【Claim 15】
The system of claim 14, wherein the interference mitigation apparatus is
configured to group the domain masters based on the interference data such that the
domain masters are not affected by interference.
22
【Claim 16】
The system of claim 15, wherein the interference mitigation apparatus is
configured to control performing Tx/Rx synchronization of the grouped domain masters
and allowing the grouped domain masters to transmit data to and 5 to receive data from
the relay terminals according to the Tx/Rx synchronization.
【Claim 17】
The system of claim 16, wherein the interference mitigation apparatus is
10 configured to estimate a channel status for each port by using test signals
transmitted/received between the domain masters and the relay terminals.