Technical Field
The present invention relates to the field of communications, and in particular to
a method for analyzing a cause of link failure, a method of network optimization and
an apparatus.
Background Art
In a self-optimizing network (SON), after link failure occurs in terminal
equipment, the terminal equipment will provide relevant information on the local cell
and neighboring cells in the link failure, such as measurement information and
location information, etc., to a network side. Then the network side will analyze a
cause of the link failure according to the information, so as to take corresponding
measures to optimize performance of the system.
In the implementation of the present invention, the inventors found that a defect
of the prior art resides in that as there are many causes for link failure, the relevant
information on the local cell and neighboring cells in the link failure, such as
measurement information and location information, etc., provided by the terminal
equipment to the network side, is unable to make the network side to take a
corresponding optimizing mechanism.
Summary of the Invention
An object of the embodiments of the present invention is to provide a method for
analyzing a cause of link failure, a method of network optimization and an apparatus.
With the methods, detailed information on link failure is provided to a network side,
thereby making the network side to optimize the network more accurately.
According to one aspect of the embodiments of the present invention, there is
provided a method for analyzing a cause of link failure, including:
determining, when link failure occurs, detailed triggering information causing the

link failure;
analyzing a cause of link failure according to the detailed triggering information
causing the link failure; and
transmitting the cause of link failure obtained by analysis to a network side.
According to another aspect of the embodiments of the present invention, there is
provided an apparatus for analyzing a cause of link failure, including:
a first processing unit configured to determine, when link failure occurs, detailed
triggering information causing the link failure;
a second processing unit configured to analyze a cause of link failure according to
the detailed triggering information causing the link failure; and
a first transmitting unit configured to transmit the cause of link failure obtained
by analysis to a network side.
According to a further aspect of the embodiments of the present invention, there
is provided a method for analyzing a cause of link failure, including:
acquiring a cause of link failure transmitted by a user side; and
determining a cause of link failure, according to the acquired cause of link failure,
or according to the acquired cause of link failure in combination with a measurement
result.
According to still another aspect of the embodiments of the present invention,
there is provided a method of network optimization, including:
Acquiring a cause of link failure transmitted by a user side;
determining a cause of link failure, according to the acquired cause of link failure,
or according to the acquired cause of link failure in combination with a measurement
result; and
optimizing a network according to the determined cause of link failure.
According to still another aspect of the embodiments of the present invention,
there is provided an apparatus for analyzing a cause of link failure, including:
a third processing unit configured to acquire a cause of link failure transmitted by
a user side; and
a fourth processing unit configured to determine a cause of link failure, according

to the acquired cause of link failure, or according to the acquired cause of link failure
in combination with a measurement result.
According to still another aspect of the embodiments of the present invention,
there is provided an apparatus of network optimization, including:
a fifth processing unit configured to acquire a cause of link failure transmitted by
a user side; and
a sixth processing unit configured to determine a cause of link failure, according
to the acquired cause of link failure, or according to the acquired cause of link failure
in combination with a measurement result; and
a first optimizing unit configured to optimize a network according to the
determined cause of link failure.
According to still another aspect of the embodiments of the present invention,
there is provided a method for analyzing a cause of link failure, including:
determining, when link failure occurs, detailed triggering information causing the
link failure; and
transmitting the detailed triggering information, as a cause of link failure; to a
network side.
According to still another aspect of the embodiments of the present invention,
there is provided an apparatus for analyzing a cause of link failure, including:
a seventh processing unit configured to determine, when link failure occurs,
detailed triggering information causing the link failure; and
a second transmitting unit configured to transmit the detailed triggering
information, as a cause of link failure, to a network side.
According to still another aspect of the embodiments of the present invention,
there is provided a method for analyzing a cause of link failure, including:
acquiring detailed triggering information causing the link failure transmitted by a
user side; and
determining a cause of link failure, according to the acquired detailed triggering
information, or according to the acquired detailed triggering information in
combination with a measurement result.

According to still another aspect of the embodiments of the present invention,
there is provided an apparatus for analyzing a cause of link failure, including:
an eighth processing unit configured to acquire detailed triggering information
causing the link failure transmitted by a user side; and
a ninth processing unit configured to determine a cause of link failure, according
to the acquired detailed triggering information, or according to the acquired detailed
triggering information in combination with a measurement result.
According to still another aspect of the embodiments of the present invention,
there is provided a method of network optimization, including:
acquiring detailed triggering information causing the link failure transmitted by a
user side;
determining a cause of link failure, according to the acquired detailed triggering
information, or according to the acquired detailed triggering information in
combination with a measurement result; and
optimizing a network according to the determined cause of link failure.
According to still another aspect of the embodiments of the present invention,
there is provided an apparatus of network optimization, including:
a tenth processing unit configured to acquire detailed triggering information
causing the link failure transmitted by a user side;
an eleventh processing unit configured to determine a cause of link failure,
according to the acquired detailed triggering information, or according to the acquired
detailed triggering information in combination with a measurement result; and
a second optimizing unit configured to optimize a network according to the
determined cause of link failure.
According to still another aspect of the embodiments of the present invention,
there is provided a computer-readable program, wherein when the program is
executed in an apparatus for analyzing a cause of link failure, the program enables a
computer to carry out the method for analyzing a cause of link failure as described
above in the apparatus.
According to still another aspect of the embodiments of the present invention,

there is provided a storage medium in which a computer-readable program is stored,
wherein the computer-readable program enables a computer to carry out the method
for analyzing a cause of link failure as described above in an apparatus for analyzing a
cause of link failure.
According to still another aspect of the embodiments of the present invention,
there is provided a computer-readable program, wherein when the program is
executed in an apparatus of network optimization, the program enables a computer to
carry out the method of network optimization as described above in the apparatus.
According to still another aspect of the embodiments of the present invention,
there is provided a storage medium in which a computer-readable program is stored,
wherein the computer-readable program enables a computer to carry out the method
of network optimization as described above in an apparatus of network optimization.
The advantage of the embodiments of the present invention resides in that
detailed information on link failure is provided to a network side by terminal
equipment, thereby making the network side to optimize the network more accurately.
With reference to the following description and drawings, the particular
embodiments of the present invention are disclosed in detail, and the principle of the
present invention and the manners of use are indicated. It should be understood that
the scope of the embodiments of the present invention is not limited thereto. The
embodiments of the present invention contain many alternations, modifications and
equivalents within the spirits and scope of the terms of the appended claims.
Features that are described and/or illustrated with respect to one embodiment may
be used in the same way or in a similar way in one or more other embodiments and/or
in combination with or instead of the features of the other embodiments.
It should be emphasized that the term "includes/including" when used in this
specification is taken to specify the presence of stated features, integers, steps or
components but does not preclude the presence or addition of one or more other
features, integers, steps, components or groups thereof.
Brief Description of the Drawings

The above and other objects, features and advantages of the present invention will
be apparent from the following detailed description in conjunction with the drawings,
in which:
Figure 1 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 1 of the present invention;
Figure 2 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 2 of the present invention;
Figure 3 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 2 of the present invention;
Figure 4 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 5 of the present invention;
Figure 5 is a flowchart of a method of network optimization of Embodiment 6 of
the present invention;
Figure 6 is a schematic diagram of the structure of an apparatus for analyzing a
cause of link failure of Embodiment 7 of the present invention;
Figure 7 is a schematic diagram of the structure of an apparatus for analyzing a
cause of link failure of Embodiment 8 of the present invention;
Figure 8 is a schematic diagram of the structure of an apparatus of network
optimization of Embodiment 9 of the present invention;
Figure 9 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 10 of the present invention;
Figure 10 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 11 of the present invention;
Figure 11 is a flowchart of a method of network optimization of Embodiment 12
of the present invention;
Figure 12 is a schematic diagram of the structure of an apparatus for analyzing a
cause of link failure of Embodiment 13 of the present invention;
Figure 13 is a schematic diagram of the structure of an apparatus for analyzing a
cause of link failure of Embodiment 14 of the present invention; and
Figure 14 is a schematic diagram of the structure of an apparatus of network

optimization of Embodiment 15 of the present invention.
Detailed Description of the Invention
Various embodiments of the present invention shall be described below with
reference to the accompanying drawings. These embodiments are illustrative only and
are not intended to limit the present invention. For easy understanding of the principle
and embodiments of the present invention by those skilled in the art, the embodiments
of the present invention shall be described taking an analysis of cause of link failure
of an SON network as an example. However, it should be understood that the present
invention is not limited thereto, and is applicable to other systems related to a cause of
link failure.
In an actual network system, there are many causes of link failure. However, in
the prior art, after link failure occurs in terminal equipment, the terminal equipment
will provide relevant information on the local cell and neighboring cells in the link
failure, such as measurement information and location information, etc., to a network
side. Such information is insufficient to make the network side to accurately
determine a root cause of the link failure, and hence cannot accurately perform
optimization. Therefore, with the embodiments of the present invention, detailed
information, such as detailed triggering information causing the link failure, is
provided to a network side, thereby making the network side to optimize the network
more accurately.
Furthermore, the terminal equipment may further analyze the detailed triggering
information causing the link failure, such as a physical layer problem, a random
process failure of a medium access control (MAC) layer, and the number of
retransmissions at radio link control (RLC) layer reaching a maximum value, etc., so
as to obtain a more detailed cause of the link failure. However, in the prior art, the
terminal equipment does not differentiate causes of link failure, and cannot provide
information on detailed causes of link failure to the network side, thereby resulting in
that the network side cannot employ more pertinent measures to optimize the network.
With the embodiments of the present invention, the network side may be made to

obtain detailed information on link failure, and hence to obtain more accurate
optimized network performance.
The method for analyzing a cause of link failure of an embodiment of the present
invention shall be described below in detail.
Fig. 1 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 1 of the present invention. As shown in Fig. 1, the method includes:
step 101: determining, when link failure occurs, detailed triggering information
causing the link failure;
in this embodiment, there are much detailed triggering information causing the
link failure, such as a physical layer problem, a random access problem of a medium
access control layer, and an uplink radio link control layer transmission problem, etc.;
for example, when UE receives no enough indication (such as N311, see 3 GPP
TS36.331) on link becoming better (such as in-sync indication, see 3GPP TS36.331)
within a certain period of time (such as T310, see 3GPP TS36.331), the UE may
determine that the detailed triggering information of the link failure is a physical layer
problem;
or when the UE receives indication on failure of a random access procedure of an
MAC layer, it may determine that the detailed triggering information of the link
failure is a random access problem of an MAC layer;
or when the number of retransmissions at a RLC layer reaches a maximum value,
the UE may determine that the detailed triggering information of the link failure is an
RLC layer transmission problem;
step 102: analyzing a cause of link failure according to the detailed triggering
information causing the link failure;
in this embodiment, the UE may analyzes detailed causes of link failure for
different pieces of triggering information, such as a handover configuration problem,
a coverage hole, and a random access problem of an MAC layer;
step 103: transmitting the cause of link failure obtained by analysis to a network
side.
in this embodiment, the UE may transmit a detailed cause in detailed

configuration information obtained by analysis to the network side, so that the
network side determines a root cause of the link failure according to the cause or
according to the cause in combination with a measurement result, so as to take
corresponding measures to optimize the network more accurately;
wherein, the cause of link failure in the detailed configuration information may be
included in link failure information for transmission to the network side; however, it
is not limited thereto, and other messages may be employed for transmitting the
information.
The method for analyzing a cause of link failure in the detailed triggering
information causing the link failure shall be described below in detail with reference
to the accompanying drawings.
Fig. 2 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 2 of the present invention. This embodiment is described taking a
physical layer problem as an example. As shown Fig. 2, the method includes:
step 201: determining by UE that the link failure is a downlink physical layer
problem;
in this embodiment, whether a timer T310 expires may be judged, and the link
failure may be determined as a downlink physical layer problem if the timer expires;
step 202: determining whether a measurement report is triggered, and executing
step 203 when the measurement report is triggered, otherwise, executing step 205;
in this embodiment, any manner in the prior art may be employed to determine
whether to trigger the measurement report, such as determining by judging whether an
event triggering the measurement report occurs; for example, the measurement report
will be triggered when a signal intensity/quality of a neighboring cell is greater than
that of a serving cell by a threshold value;
step 203: determining by the UE that the cause of link failure is a handover
configuration problem when the measurement report is triggered in step 202;
in this case, the handover configuration problem may be due to that a handover
parameter (such as a cell individual offset, see 3GPP TS36.331) of the UE for a target
cell is set too small, which results in that the UE does not finish handover when a

signal of the serving cell received by the UE is very weak;
step 204: recoding an analysis result by the UE;
in this embodiment, the UE may record the analysis result "handover
configuration problem" in such a case in a link failure report and transmit the analysis
result to the network side via the link failure report; however, it is not limited thereto,
and the analysis result may also be recorded separately and transmitted to the network
side, for use by the network side in analyzing a cause of link failure or optimizing the
network;
wherein, in case of the downlink physical layer problem, the analysis result
"handover configuration problem" may be recorded in a manner as follows:
"handover configuration problem(a physical layer problem, measurement report
triggered)"; or "handover configuration problem (T310 expires, measurement report
triggered)", etc.;
wherein, "measurement report triggered" may be optional information, and may
not be recorded;
step 205: determining further by the UE whether there exists a neighboring cell of
better signal quality when it is determined in step 202 that the measurement report is
not triggered, and executing step 206 when a judgment result is yes, otherwise,
executing step 208;
step 206: determining by the UE that the cause of link failure is a handover
configuration problem when a judgment result in step 205 is yes;
in this case, the handover configuration problem may be due to that a handover
parameter (such as a cell individual offset, see 3GPP TS36.331) of the UE for a target
cell is set too small, which results in that the UE does not finish handover when a
signal of the serving cell received by the UE is very weak;
step 207: recoding an analysis result by the UE;
in this embodiment, the UE may record the analysis result "handover
configuration problem" in such a case in a link failure report and transmit the analysis
result to the network side via the link failure report; however, it is not limited thereto,
and the analysis result may also be recorded separately and transmitted to the network

side, for use by the network side in analyzing a cause of link failure or optimizing the
network;
wherein, in case of the downlink physical layer problem, the analysis result
"handover configuration problem" may be recorded in a manner as follows:
"handover configuration problem (a physical layer problem, measurement report is
not triggered, there exists a neighboring cell of better signal quality) "; or "handover
configuration problem (T310 expires, measurement report is not triggered, there exists
a neighboring cell of better signal quality)", etc.;
wherein, "measurement report is not triggered, there exists a neighboring cell of
better signal quality" may be optional information, and may not be recorded;
step 208: determining further by the UE whether there exists recently successful
UL transmission before the link failure occurs when the judgment result in step 205 is
no, and executing step 209 when there exists recently successful UL transmission,
otherwise, executing step 211;
in this embodiment, the recently successful UL transmission refers to occurred
successful UL transmission before a downlink problem occurs (such as N310 pieces
of continuous out-of-sync indication from a lower layer are received);
step 209: determining that the cause of link failure is "coverage hole" when a
determination result in step 208 is that there exists recently successful UL
transmission;
in this embodiment, the coverage hole refers to that the UE cannot transmit data
packets in an uplink direction successfully, and/or cannot receive data packets in a
downlink direction;
in this case, the coverage hole is only a downlink coverage hole, referring to that
the UE cannot receive data packets in a downlink direction;
step 210: recoding an analysis result by the UE;
in this embodiment, the UE may record the analysis result "coverage hole" in
such a case in a link failure report and transmit the analysis result to the network side
via the link failure report; however, it is not limited thereto, and the analysis result
may also be recorded separately and transmitted to the network side, for use by the

network side in analyzing a cause of link failure or optimizing the network;
wherein, in case of the physical layer problem, the analysis result "coverage hole"
may be recorded in a manner as follows: "coverage hole (a physical layer problem,
measurement report is not triggered, there exists no neighboring cell of better signal
quality, there exists recently successful UL transmission) "; or "coverage hole (T310
expires, measurement report is not triggered, there exists no neighboring cell of better
signal quality, there exists recently successful UL transmission) ", etc.;
wherein, "there exists no neighboring cell of better signal quality, there exists
recently successful UL transmission" may be optional information, and may not be
recorded;
step 211: determining that the cause of link failure is "coverage hole" when the
determination result in step 208 is that there exists no recently successful UL
transmission;
in this embodiment, it may be determined as "downlink coverage hole, uplink
unknown";
step 212: recoding an analysis result;
in this embodiment, the UE may record the analysis result "coverage hole" in
such a case in a link failure report and transmit the analysis result to the network side
via the link failure report; however, it is not limited thereto, and the analysis result
may also be recorded separately and transmitted to the network side, for use by the
network side in analyzing a cause of link failure or optimizing a network;
wherein, in case of the physical layer problem, the analysis result "coverage hole"
may be recorded in a manner as follows: "coverage hole (a physical layer problem,
measurement report not triggered, there exists no neighboring cell of better signal
quality, there exists no recently successful UL transmission) "; or "coverage hole
(T310 expires, measurement report is not triggered, there exists no neighboring cell of
better signal quality, there exists no recently successful UL transmission) ", etc.;
wherein, "measurement report is not triggered, there exists no neighboring cell of
better signal quality, there exists no recently successful UL transmission" may be
optional information, and may not be recorded;

steps 213, 214 and 215: transmitting an analysis result by the UE to the network
side;
in this embodiment, the analysis result may be included in the link failure report
for transmitting to the network side, and may also be separately transmitted;
furthermore, the analysis result may be transmitted only upon request by the network
side.
In the above embodiment, it should be noted that steps 204, 207, 210 and 212 are
optional; furthermore, the process shown in Fig. 2 is just an embodiment of the
present invention, and to those skilled in the art, each step may be set according to an
actual situation, only if the following is satisfied: when a measurement report is
triggered, it is determined that the cause of link failure is a handover configuration
problem; when a measurement report is not triggered and there exists a neighboring
cell of better signal quality, it is determined that the cause of link failure is a handover
configuration problem; when a measurement report is not triggered, there exists no
neighboring cell of better signal quality and there exists recently successful UL
transmission before the link failure, it is determined that the cause of link failure is
only downlink coverage hole; and when a measurement report is not triggered, there
exists no neighboring cell of better signal quality and there exists no recently
successful UL transmission before the link failure, it is determined that the cause of
link failure is downlink coverage hole, and uplink is unknown.
It can be seen from the above embodiment that in the case that the link failure is a
physical layer problem, the UE may analyze detailed causes of link failure according
to the above processes, and report an analysis result to the network side. In this way,
the network side may analyze causes of link failure according to the information
reported by the UE, so as to perform network optimization more accurately.
Fig. 3 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 3 of the present invention. This embodiment is described taking an
uplink RLC layer transmission problem as an example. As shown Fig. 3, the method
includes:
step 301: determining by the UE that the link failure is an RLC layer transmission

problem;
in this embodiment, when the UE transmits data to a base station, when the base
station does not correctly receive the data, the base station will notify the UE to
retransmit the data, and the UE judges whether a maximum number of times of
retransmission of an RLC layer is reached, when the maximum number of times is
reached, it may be determined that the link failure is an uplink RLC layer
transmission problem;
step 302: determining whether a measurement report is triggered, and executing
step 303 when the measurement report is triggered, otherwise, executing step 307;
in this embodiment, a manner of determining whether a measurement report is
triggered is as described in Embodiment 2, which shall not be described herein any
further;
step 303: determining further by the UE whether the measurement report is
successfully transmitted when it is determined in step 302 that the measurement report
is triggered, and executing step 304 when it is successfully transmitted, otherwise,
executing step 311;
in this embodiment, the UE receives an acknowledgement message fed back from
the network side after transmitting the measurement report, and may determine that
the measurement report is successfully transmitted;
step 304: determining further whether a handover completion message is
successfully transmitted when it is determined in step 303 that that the measurement
report is successfully transmitted, and executing step 305 when the handover
completion message is not successfully transmitted, otherwise, turning back to step
302;
in this embodiment, the handover completion message is the last message in a
completed handover process, which is transmitted from the UE to a target base station,
such as an RRC connection reconfiguration completion message;
step 305: determining that the cause of link failure is a handover configuration
problem when it is determined in step 304 that the handover completion message is
not successfully transmitted;

in this embodiment, a handover configuration problem may be determined as the
handover completion message cannot be transmitted;
in particular, it may be a handover parameter problem due to that a handover
parameter (such as a cell individual offset, see 3GPP TS36.331) of the UE for a target
cell is set too large, which results in that the UE does not finish handover or link
failure occurs after handover is finished when a signal of the target cell is very weak
as the UE is handed over to the target cell;
step 306: recoding an analysis result by the UE;
in this embodiment, the UE may record the analysis result "handover
configuration problem" in such a case in a link failure report and transmit the analysis
result to the network side via the link failure report; however, it is not limited thereto,
and the analysis result may also be recorded separately and transmitted to the network
side, for use by the network side in analyzing a cause of link failure or optimizing the
network;
wherein, in case of the uplink RLC layer transmission problem, the analysis result
"handover configuration problem" may be recorded in a manner as follows:
"handover configuration problem (an uplink RLC layer transmission problem,
handover completion message cannot be transmitted) ";
wherein, "handover completion message cannot be transmitted" may be optional
information, and may not be recorded;
step 307: determining further by the UE whether there exists a neighboring cell of
better signal quality when it is determined in step 302 that the measurement report is
not triggered, and executing step 315 when a determination result is yes, otherwise,
executing step 308;
step 308: determining further by the UE whether there exists recently successfully
DL transmission when the determination result is no in step 307, and executing step
309 when a judgment result is yes, otherwise, executing step 313;
wherein, the recently successfully downlink transmission refers to occurred
successful downlink transmission before determining the cause of link failure is the
RLC layer transmission problem;

step 309: determining by the UE the cause of link failure is only an uplink
coverage hole when the judgment result in step 308 is yes;
step 310: recoding an analysis result by the UE;
in this embodiment, the UE may record the analysis result "coverage hole" in
such a case in a link failure report and transmit the analysis result to the network side
via the link failure report; however, it is not limited thereto, and the analysis result
may also be recorded separately and transmitted to the network side, for use by the
network side in analyzing a cause of link failure or optimizing the network;
wherein, in case of the uplink RLC layer transmission problem, the analysis result
"coverage hole" may be recorded in a manner as follows: "coverage hole" (an uplink
RLC layer transmission problem, measurement report not triggered, there exists no
neighboring cell of better signal quality, there exists recently successful DL
transmission);
wherein, "measurement report is not triggered, there exists no neighboring cell of
better signal quality, there exists recently successful DL transmission" may be
optional information, and may not be recorded;
step 311: determining by the UE that the cause of link failure is handover
configuration problem when the judgment result in step 303 is no;
in this embodiment, it may be a handover parameter problem due to that a
handover parameter (such as a cell individual offset, see 3GPP TS36.331) of the UE
for a target cell is set too small, which results in that the UE does not finish handover
when a signal of the serving cell received by the UE is very weak;
step 312: recoding an analysis result by the UE;
in this embodiment, the UE may record the analysis result "handover
configuration problem" in such a case in a link failure report and transmit the analysis
result to the network side via the link failure report; however, it is not limited thereto,
and the analysis result may also be recorded separately and transmitted to the network
side, for use by the network side in analyzing a cause of link failure or optimizing the
network;
wherein, in case of the uplink RLC layer transmission problem, the analysis result

"handover configuration problem" may be recorded in a manner as follows:
"handover configuration problem (an uplink RLC transmission problem,
measurement report is triggered, measurement report is not transmitted
successfully)";
wherein, "measurement report is triggered, measurement report is not transmitted
successfully" may be optional information, and may not be recorded;
step 313: determining by the UE that the cause of link failure is an uplink
coverage hole and downlink is unknown when the judgment result in step 308 is no;
step 314: recoding an analysis result by the UE;
in this embodiment, the UE may record the analysis result "coverage hole" in
such a case in a link failure report and transmit the analysis result to the network side
via the link failure report; however, it is not limited thereto, and the analysis result
may also be recorded separately and transmitted to the network side, for use by the
network side in analyzing a cause of link failure or optimizing the network;
wherein, in case of the uplink RLC layer transmission problem, the analysis result
"coverage hole" may be recorded in a manner as follows: "coverage hole (an uplink
RLC transmission problem, measurement report is not triggered, there exists no
neighboring cell of better signal quality, there exists no recently successful downlink
transmission)";
wherein, "measurement report is not triggered, there exists no neighboring cell of
better signal quality, there exists no recently successful downlink transmission" may
be optional information, and may not be recorded;
step 315: determining by the UE that the cause of link failure is handover
configuration problem when the judgment result in step 307 is yes;
wherein, in particular, the handover configuration problem may be a handover
parameter problem due to that a handover parameter (such as a cell individual offset,
see 3GPP TS36.331) of the UE for a target cell is set too small, which results in that
the UE does not finish handover when a signal of the serving cell received by the UE
is very weak;
step 316: recoding an analysis result by the UE;

in this embodiment, the UE may record the analysis result "handover
configuration problem" in such a case in a link failure report and transmit the analysis
result to the network side via the link failure report; however, it is not limited thereto,
and the analysis result may also be recorded separately and transmitted to the network
side, for use by the network side in analyzing a cause of link failure or optimizing the
network;
wherein, in case of the uplink RLC layer transmission problem, the analysis result
"handover configuration problem" may be recorded in a manner as follows:
"handover configuration problem (an uplink RLC transmission problem,
measurement report is not triggered, there exists a neighboring cell of better signal
quality) ";
wherein, "measurement report is not triggered, there exists a neighboring cell of
better signal quality" may be optional information, and may not be recorded;
steps 317-321: transmitting the analysis result by the UE to the network side;
in this embodiment, the analysis result may be included in the link failure report
and transmit the analysis result to the network side via the link failure report, and may
also be separately transmitted; furthermore, the analysis result may be transmitted
upon request by the network side, and may also be transmitted immediately after it is
obtained; in a particular embodiment, it may be determined according to an actual
situation.
In the above embodiment, it should be noted that steps 306, 310, 312, 314 and
316 are optional; furthermore, the process shown in Fig. 3 is just an embodiment of
the present invention, and to those skilled in the art, each step may be set according to
an actual situation, only if the following is satisfied: when a measurement report is
triggered and the measurement report is not transmitted successfully, it is determined
that the cause of link failure is a handover configuration problem; when a
measurement report is triggered and the measurement report is successfully
transmitted, and a handover completion message is not transmitted successfully, it is
determined that the cause of link failure is a handover configuration problem; when a
measurement report is not triggered and there exists a neighboring cell of better signal

quality, it is determined that the cause of link failure is a handover configuration
problem; when a measurement report is not triggered, there exists no neighboring cell
of better signal quality and there exists recently successful downlink transmission
before the link failure, it is determined that the cause of link failure is only uplink
coverage hole; and when a measurement report is not triggered, there exists no
neighboring cell of better signal quality and there exists no recently successful DL
transmission before the link failure, it is determined that the cause of link failure is
uplink coverage hole, and downlink is unknown.
It can be seen from the above embodiment that in the case that the cause of link
failure is an uplink RLC transmission problem, the UE may analyze detailed causes of
link failure according to the above processes, and report an analysis result to the
network side. In this way, the network side may analyze causes of link failure
according to the information reported by the UE, so as to perform network
optimization more accurately.
Embodiment 4 of the present invention further provides a method for analyzing a
cause of link failure.
In an embodiment of the present invention, when the cause of link failure is a
random access problem of an MAC layer, the UE determines that the cause of the link
failure is an uplink problem related to a random access process of the MAC layer in
receiving indication on random process failure of the MAC layer, such as incorrect
setting of transmission power, and improper resource configuration of a physical
random access channel (PRACH), etc..
Furthermore, the UE may record the analysis result "random access problem of
an MAC layer". Wherein, the UE may record the analysis result in such a case in a
link failure report and transmit the analysis result to the network side via the link
failure report; however, it is not limited thereto, and the analysis result may also be
recorded separately and transmitted to the network side, for use by the network side in
analyzing a cause of link failure or optimizing the network.
It can be seen from the above embodiment that the UE may obtain information on
detailed causes of link failure by analyzing the causes of link failure, and report an

analysis result to the network side. In this way, the network side may analyze causes
of link failure according to the information reported by the UE, so as to perform
network optimization more accurately.
Fig. 4 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 5 of the present invention. For the base station where the UE is located
when link failure occurs in the UE, as shown in Fig. 4, the method includes:
step 401: acquiring information on a cause of link failure transmitted by a user
side;
in this embodiment, the information on a cause of link failure may be that
described in embodiments 1-4 above;
for example, a handover configuration problem (an uplink RLC transmission
problem, a handover completion message cannot be transmitted);
a handover configuration problem (an uplink RLC transmission problem, a
measurement report is triggered, the measurement report is not transmitted
successfully);
a handover configuration problem (an uplink RLC transmission problem, a
measurement report is not triggered, there exists a neighboring cell of better signal
quality);
coverage hole (an uplink RLC transmission problem, a measurement report is not
triggered, there exists no neighboring cell of better signal quality, there exists recently
successful downlink transmission);
coverage hole (an uplink RLC transmission problem, a measurement report is not
triggered, there exists no neighboring cell of better signal quality, there exists no
recently successful downlink transmission);
a handover configuration problem (T310 expires, a measurement report is
triggered);
a handover configuration problem (T310 expires, a measurement report is not
triggered, there exists a neighboring cell of better signal quality);
coverage hole (T310 expires, a measurement report is not triggered, there exists
no neighboring cell of better signal quality, there exists recently successful uplink

transmission);
coverage hole (T310 expires, a measurement report is not triggered, there exists
no neighboring cell of better signal quality, there exists no recently successful uplink
transmission); and
a random access problem of an MAC layer;
in the above information, some are optional, which are as described in
embodiments 1-4, and shall not be described herein any further;
furthermore, the base station where the UE is located does not obtain the above
information directly, and the information may be transmitted to the base station by
another base station via an air-interface message or an inter-base station message,
thereby enabling the base station to obtain a cause of link failure;
in this embodiment, the information on a cause of link failure may be transmitted
via a link failure report; furthermore, it may also be transmitted separately, or
included in another message for transmission;
step 402: determining a cause of link failure, according to the acquired cause of
link failure, or according to the acquired cause of link failure in combination with a
measurement result of itself;
in this embodiment, after obtaining the cause of link failure, the base station may
use the obtained cause of link failure to determine a root cause of the link failure;
furthermore, in this embodiment, in order to determine a root cause of the link
failure more accurately, the base station may determine the root cause of the link
failure according to the obtained cause of link failure, and determine the root cause of
the link failure more accurately in combination with the measurement result of itself;
in this embodiment, the measurement of itself may be SRS measurement, etc.
Fig. 5 is a flowchart of a method of network optimization of Embodiment 6 of the
present invention. For the base station where the UE is located when link failure
occurs in the UE, as shown in Fig. 5, the method includes:
steps 501 and 502: similar to steps 401 and 402 in Embodiment 5 shown in Fig. 4,
which shall not be described herein any further;
step 503: in step 502, the base station may perform corresponding network

optimization after determining the root cause of the link failure.
Determination of the root cause of the link failure and network optimization by
the base station in combination with the measurement result of itself shall be
described below by way of examples.
Example 1: a handover configuration problem
The UE reports following causes of link failure, for example, a handover
configuration problem (T310 expires, a measurement report is triggered), (T310
expires, a measurement report is not triggered), (an uplink RLC transmission problem,
a handover completion message cannot be transmitted), (an uplink RLC transmission
problem, a measurement report cannot be transmitted successfully), etc.;
the measurement result of the base station itself: the base station may judge
whether handover is too early, handover is too late, or being handed over to a wrong
cell, according to information of the UE during the handover;
in this way, after obtaining a cause of link failure reported by the UE, the base
station compares the cause with a judgment result of itself, such as handover is too
early, handover is too late, or being handed over to a wrong cell, so as to determine a
root cause of the link failure, thereby deciding a parameter to be adjusted, and
achieving an object of network optimization.
For example, although the base station is able to determine that a cause of link
failure is that handover is too late, if a cause reported by the UE to the base station is
"a handover configuration problem (T310 expires, a measurement report is
triggered)", the base station may determine according to the above information which
parameters should be adjusted, for example, a parameter having measurement
configuration, such as time to trigger (see TS36.331), so as to optimize the network
by adjusting a corresponding parameter.
Example 2: coverage hole
Similar to the above analysis, the UE reports following causes of link failure:
coverage hole (T310 expires, a measurement report is not triggered, there exists
recently successful UL transmission), coverage hole (T310 expires, a measurement
report is not triggered, there exists no recently successful UL transmission);

if the base station is able to determine that a cause of link failure is coverage hole,
when the base station obtains a cause of link failure from the UE, the base station may
determine whether the coverage hole is uplink coverage hole, downlink coverage hole,
or uplink and downlink coverage holes, according to a measurement result of itself
and an analysis result reported by the UE.
A detailed process is as follows:
the base station acquires the cause of link failure, such as uplink, downlink, or
uplink and downlink coverage holes, reported by the UE, initializes those MDT report
procedures of the UE near the position where the link failure occurs, and further
determines a problem of coverage hole according to the MDT report; in this way, the
base station notifies an OAM server of a determined result for optimizing
performance of the network.
Example 3: a random access problem of an MAC layer
when a cause of link failure reported by the UE is a random access problem of an
MAC layer, the base station is able to initialize those random access channel (RACH)
report procedures of the UE near the position where the link failure occurs after
acquiring the information, thereby assisting in finding a cause of a random access
problem; in this way, the RACH may be optimized according to a particular cause, so
as to optimize the network.
It can be seen from the above embodiment that the UE analyzes causes of link
failure according to detailed triggering information, and provides an analysis result to
the network side, so that the base station determines a root cause of the link failure
according to the analysis result, or further in combination of a measurement result of
itself after obtaining the analysis result, so as to optimize the network more
accurately.
A person of ordinary skill in the art may understand that all or part of the steps in
the method carrying out the above embodiment may be carried out by related
hardware instructed by a program. The program may be stored in a computer-readable
storage medium. And when being executed, the program may include all or part of the
steps in the method in the above embodiment, and the storage medium may include an

ROM, an RAM, a floppy disc, and a compact disc, etc.
Embodiments of the present invention further provide an apparatus for analyzing
a cause of link failure and an apparatus of network optimization, as described in the
embodiments below. As the principles of the apparatuses for solving problems are
similar to those of the above method for analyzing a cause of link failure and the
method of network optimization based on these apparatuses, the implementation of
the methods may be referred to for the implementation of the apparatuses, and the
repeated parts shall not be described any further.
Fig. 6 is a schematic diagram of an apparatus for analyzing a cause of link failure
of Embodiment 7 of the present invention. The apparatus includes: a first processing
unit 601, a second processing unit 602 and a first transmitting unit 603; wherein,
the first processing unit 601 is configured to determine, when link failure occurs,
detailed triggering information causing the link failure; in this embodiment, a manner
of processing of the first processing unit 601 is as described in step 101 in
Embodiment 1, which shall not be described herein any further;
the second processing unit 602 is configured to analyze a cause of link failure
according to the detailed triggering information causing the link failure; wherein, a
manner of processing of the second processing unit 602 is as described in step 102 in
Embodiment 1 and in embodiments 2-4, which shall not be described herein any
further;
the first transmitting unit 103 is configured to transmit the cause of link failure
obtained by analysis to a network side; in this embodiment, the transmission of the
cause of link failure by the first transmitting unit 103 is as described in step 103 in
Embodiment 1, which shall not be described herein any further.
In this embodiment, a function of the second processing unit 602 shall be
described with respect to a detailed cause of link failure.
In this embodiment, when the detailed cause of link failure is a physical layer
problem, the second processing unit 602 is configured to:
determine, when a measurement report has been triggered, that the cause of link
failure is a handover configuration problem;

determine, when a measurement report has not been triggered and there exists a
neighboring cell of good signal quality, that the cause of link failure is a handover
configuration problem;
determine, when a measurement report has not been triggered, there exists no
neighboring cell of good signal quality and there exists recently successful UL
transmission before the link failure occurs, that the cause of link failure is a downlink
coverage hole; and
determine, when a measurement report has not been triggered, there exists no
neighboring cell of good signal quality and there exists no recently successful UL
transmission before the link failure occurs, that the cause of link failure is a downlink
coverage hole, and uplink is unknown.
In this case, a manner of processing of the second processing unit 602 is as
described in Embodiment 2, which shall not be described herein any further.
In this embodiment, when the detailed cause of the link failure is a radio link
control layer transmission problem, the second processing unit 602 is configured to:
determine, when a measurement report is triggered and is not transmitted
successfully, that the cause of link failure is a handover configuration problem;
determine, when a measurement report is triggered and is transmitted successfully
and a handover completion message is not transmitted successfully, that the cause of
link failure is a handover configuration problem;
determine, when a measurement report has not been triggered and there exists a
neighboring cell of good signal quality, that the cause of link failure is a handover
configuration problem;
determine, when a measurement report has not been triggered, there exists no
neighboring cell of good signal quality and there exists recently successful downlink
transmission before the link failure occurs, that the cause of link failure is an uplink
coverage hole; and
determine, when a measurement report has not been triggered, there exists no
neighboring cell of good signal quality and there exists no recently successful
downlink transmission before the link failure occurs, that the cause of link failure is

an uplink coverage hole and the downlink is unknown.
In this case, a manner of processing of the second processing unit 602 is as
described in Embodiment 3, which shall not be described herein any further.
In this embodiment, when the detailed cause of the link failure is a random access
problem of a medium access control layer, the second processing unit 602 is
configured to:
determine, after indication of failure of a random procedure of a medium access
control layer is received, that the cause of link failure is an uplink problem associated
with the random procedure of a medium access control layer.
In this case, a manner of processing of the second processing unit 602 is as
described in Embodiment 4, which shall not be described herein any further.
In this embodiment, the apparatus may be UE, such as terminal equipment, for
example, a PDA, a mobile terminal, and a computer, etc.
Fig. 7 is a schematic diagram of an apparatus for analyzing a cause of link failure
of Embodiment 8 of the present invention. The apparatus includes: a third processing
unit 701 and a fourth processing unit 702; wherein,
the third processing unit 701 is configured to acquire information on a cause of
link failure transmitted by a user side;
in this embodiment, information on the cause of link failure is as described in step
401 in Embodiment 5, which shall not be described herein any further;
the fourth processing unit 702 is configured to determine a cause of link failure
according to the acquired cause of link failure, or according to the acquired cause of
link failure in combination with a measurement result;
in this embodiment, the information on the cause of link failure is as described in
step 402 in Embodiment 5, which shall not be described herein any further.
In the above embodiment, the apparatus may be a base station where the UE is
located when the link failure occurs in the UE.
Fig. 8 is a schematic diagram of an apparatus of network optimization of
Embodiment 9 of the present invention. The apparatus includes: a fifth processing
unit 801, a sixth processing unit 802 and a first optimizing unit 803; wherein,

the fifth processing unit 801 is configured to acquire a cause of link failure
transmitted by a user side;
the sixth processing unit 802 is configured to determine a cause of link failure
according to the acquired cause of link failure, or according to the acquired cause of
link failure in combination with a measurement result; and
the first optimizing unit 803 is configured to optimize a network according to the
determined cause of link failure.
In this embodiment, execution processes of the fifth processing unit 801 and the
sixth processing unit 802 are as described in steps 401 and 402 in Embodiment 5, and
an execution process of the first optimizing unit 803 is as described in step 503 in
Embodiment 6, which shall not be described herein any further.
In the above embodiment, the apparatus may be a base station where the UE is
located when the link failure occurs in the UE.
It can be seen from the above embodiment that the UE may obtain detailed
information on a cause of link failure by analyzing causes of link failure, and reports
an analysis result to the network side. In this way, the network side may analyze the
causes of link failure according to the information reported by the UE, so as to
optimize the network more accurately.
Fig. 9 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 10 of the present invention. For UE, as shown in Fig. 9, the method
includes:
step 901: determining, when link failure occurs, detailed triggering information
causing the link failure; and
step 902: transmitting the detailed triggering information, as the cause of link
failure, to a network side.
In the above embodiment, the detailed triggering information is as described in
Embodiment 1, which shall not be described herein any further.
It can be seen from the above embodiment that when link failure occurs, UE
provides the detailed triggering information causing the link failure to the network
side, so that the network side determines a cause of the link failure more accurately

according to the information, so as to optimize the network more accurately.
Fig. 10 is a flowchart of a method for analyzing a cause of link failure of
Embodiment 11 of the present invention. For the base station where the UE is located
when link failure occurs in the UE, as shown in Fig. 10, the method includes:
step 1001: acquiring detailed triggering information causing the link failure
transmitted by a user side;
wherein, the UE transmits the detailed triggering information to the network side
as a cause of link failure, and the base station where the UE is located does not obtain
the above information directly, and the information may be transmitted to the base
station where the UE is located by another base station via an air-interface message or
an inter-base station message, thereby enabling the base station to obtain the cause of
link failure;
in this embodiment, the information on a cause of link failure may be transmitted
via a link failure report; furthermore, it may also be transmitted separately, or
included in another message for transmission;
step 1002: determining the cause of link failure, according to the acquired
detailed triggering information, or according to the acquired detailed triggering
information in combination with a measurement result.
Fig. 11 is a flowchart of a method of network optimization of Embodiment 12 of
the present invention. For the base station where the UE is located when link failure
occurs, as shown in Fig. 11, the method includes:
steps 1101 and 1102 are similar to step 1001 and 1002 in Embodiment 11, which
shall not be described herein any further;
step 1103: optimizing the network according to the determined root cause of link
failure.
It can be seen from the above embodiment that when link failure occurs, the UE
provides the detailed triggering information causing the link failure to the network
side, so that the network side determines a cause of the link failure more accurately
according to the information, so as to optimize the network more accurately.
The method for analyzing a cause of link failure and method of network

optimization of the embodiments of the present invention shall be described below by
way of examples.
Example 1: a physical layer problem
the base station may determine that a cause of link failure is a handover
configuration problem,(such as handover is too early, handover is too late, or being
handed over to a wrong cell) or a coverage hole according to the detailed triggering
information and a measurement result;
the manner of judgment may be achieved by using the prior art; for example,
when the measurement result shows that there exists no neighboring cell of better
signal quality when the link failure occurs, it may be judged that it is a coverage hole;
according to the judgment result, the base station may solve the handover
configuration problem by adjusting a handover parameter (such as a cell individual
offset, see 3GPP TS36.331) of the UE for a target cell, or solve the problem of
coverage hole by increasing the coverage of the base station.
Example 2: a random access problem of a medium access control layer
the base station may determine that the cause of the link failure is an uplink
problem related to a random access process of the MAC layer according to the
detailed triggering information, such as incorrect setting of transmission power, and
improper resource configuration of a physical random access channel (PRACH);
and the base station may optimize the network performance by increasing
transmission power or increasing resources of a physical random access channel.
Example 3: an uplink radio link control layer transmission problem
The base station may judge that the configuration of the uplink is improper
according to a reported uplink radio link control layer transmission problem, such as
incorrect setting of uplink transmission power;
and the base station may optimize the network performance by adjusting the
uplink transmission power of the UE.
It can be seen from above that the above embodiments are just illustrative
embodiments of the present invention, and it is conceivable to those skilled in the art
to design schemes for determining a root cause of link failure and optimizing a

network according to the embodiments of the present invention.
Embodiment of the present invention further provide an apparatus for analyzing a
cause of link failure and an apparatus of network optimization, as described in the
embodiments below. As the principles of the apparatuses for solving problems are
similar to those of the above method for analyzing a cause of link failure and the
method of network optimization based on these apparatuses, the implementation of
the methods may be referred to for the implementation of the apparatuses, and the
repeated parts shall not be described any further.
Fig. 12 is a schematic diagram of the structure of an apparatus for analyzing a
cause of link failure of Embodiment 13 of the present invention. The apparatus
includes: a seventh processing unit 1201 and a second transmitting unit 1202;
wherein,
the seventh processing unit 1201 is configured to determine, when link failure
occurs, detailed triggering information causing the link failure; wherein, a detailed
process of determination is as described in Embodiment 1 above, which shall not be
described herein any further;
and the second transmitting unit 1202 is configured to transmit the detailed
triggering information, as a cause of link failure, to a network side; wherein, a
detailed process of transmission is as described in Embodiment 1 above, which shall
not be described herein any further.
In this embodiment, the apparatus may be UE, such as a PDA, and a mobile
terminal, etc.
Fig. 13 is a schematic diagram of the structure of an apparatus for analyzing a
cause of link failure of Embodiment 14 of the present invention. The apparatus
includes: an eighth processing unit 1301 and a ninth processing unit 1302; wherein,
the eighth processing unit 1301 is configured to acquire detailed triggering
information causing the link failure transmitted by a user side; wherein, a detailed
manner of acquisition is as described in Embodiment 11 above, which shall not be
described herein any further;
and the ninth processing unit 1302 is configured to determine a cause of link

failure, according to the acquired detailed triggering information, or according to the
acquired detailed triggering information in combination with a measurement result;
wherein, a detailed process of determination is as described in Embodiment 11 above,
which shall not be described herein any further.
In the above embodiment, the apparatus is a base station, that is, the base station
where the UE is located when link failure occurs.
Fig. 14 is a schematic diagram of the structure of an apparatus of network
optimization of Embodiment 15 of the present invention. As shown in Fig. 14, the
apparatus includes: a tenth processing unit 1401, an eleventh processing unit 1402 and
a second optimizing unit 1403; wherein,
the functions of the tenth processing unit 1401 and the eleventh processing unit
1402 are similar to those of the eighth processing unit 1301 and the ninth processing
unit 1302 in Embodiment 14, which shall not be described herein any further;
and the second optimizing unit 1403 is configured to optimize a network
according to the determined cause of link failure.
In this embodiment, the apparatus may be UE, such as a PDA, and a mobile
terminal, etc.
It can be seen from the above embodiment that when link failure occurs, the UE
provides the detailed triggering information causing the link failure to the network
side, so that the network side determines a cause of the link failure more accurately
according to the information, so as to optimize the network more accurately.
An embodiment of the present invention further provides a computer-readable
program, wherein when the program is executed in an apparatus for analyzing a cause
of link failure, the program enables a computer to carry out the method for analyzing
a cause of link failure as described in embodiments 1-5 and 10-11 in the apparatus for
analyzing a cause of link failure.
An embodiment of the present invention further provides a storage medium in
which a computer-readable program is stored, wherein the computer-readable
program enables a computer to carry out the method for analyzing a cause of link
failure as described in embodiments 1-5 and 10-11 in an apparatus for analyzing a

cause of link failure.
An embodiment of the present invention further provides a computer-readable
program, wherein when the program is executed in an apparatus of network
optimization, the program enables a computer to carry out the method of network
optimization as described in embodiments 6 and 12 in the apparatus of network
optimization.
An embodiment of the present invention further provides a storage medium in
which a computer-readable program is stored, wherein the computer-readable
program enables a computer to carry out the method of network optimization as
described in embodiments 6 and 12 in an apparatus of network optimization.
The above apparatuses and methods of the present invention may be implemented
by hardware, or by hardware in combination with software. The present invention
relates to such a computer-readable program that when the program is executed by a
logic device, the logic device is enabled to carry out the apparatus or components as
described above, or to carry out the methods or steps as described above. The present
invention also relates to a storage medium for storing the above program, such as a
hard disk, a floppy disk, a CD, a DVD, and a flash memory, etc.
The present invention is described above with reference to particular
embodiments. However, it should be understood by those skilled in the art that such a
description is illustrative only, and not intended to limit the protection scope of the
present invention. Various variants and modifications may be made by those skilled in
the art according to the spirits and principle of the present invention, and such variants
and modifications fall within the scope of the present invention.

W
e Claim:
1. A method for analyzing a cause of link failure, comprising:
determining, when link failure occurs, detailed triggering information causing the
link failure;
analyzing a cause of link failure according to the detailed triggering information
causing the link failure; and
transmitting the cause of link failure obtained by analysis to a network side.
2. The method according to claim 1, wherein the detailed triggering information
causing the link failure comprises one or more of the following: a physical layer
problem, a random access problem of a medium access control layer, and an uplink
radio link control layer transmission problem.
3. The method according to claim 1 or 2, wherein the cause of link failure
comprises one or more pieces of the following information: a handover configuration
problem, an uplink and/or downlink coverage hole, and an uplink link problem.
4. The method according to claim 1 or 2, wherein when the detailed triggering
information causing the link failure is a physical layer problem, the step of analyzing
a cause of link failure comprises:
determining, when a measurement report has been triggered, that the cause of link
failure is a handover configuration problem;
determining, when a measurement report has not been triggered and there exist
neighboring cells with good signal quality, that the cause of link failure is a handover
configuration problem; and
determining, when a measurement report has not been triggered and there exists
no neighboring cell with good signal quality, that the cause of link failure is a
coverage hole.
5. The method according to claim 4, wherein when a measurement report has not
been triggered and there exists no neighboring cell with good signal quality, it is
determined that the cause of link failure is a downlink coverage hole, when there
exists recent successful uplink transmission before the link failure; and
it is determined that the cause of link failure is a downlink coverage hole and the
uplink is unknown, when there exists no recent successful uplink transmission before
the link failure.
6. The method according to claim 1 or 2, wherein when the detailed triggering
information causing the link failure is a random access problem of a medium access
control layer, the step of analyzing a cause of link failure comprises:
determining, after indication of failure of a random procedure of a medium access
control layer is received, that the cause of link failure is an uplink problem associated

with the random procedure of a medium access control layer.
7. The method according to claim 1 or 2, wherein when the detailed triggering
information causing the link failure is an uplink radio link control layer transmission
problem, the step of analyzing a cause of link failure comprises:
determining, when a measurement report is triggered and is not transmitted
successfully, that the cause of link failure is a handover configuration problem;
determining, when a measurement report is triggered and is transmitted
successfully and a handover completion message is not transmitted successfully, that
the cause of link failure is a handover configuration problem;
determining, when a measurement report has not been triggered and there exist
neighboring cells with good signal quality, that the cause of link failure is a handover
configuration problem;
determining, when a measurement report has not been triggered, there exists no
neighboring cell with good signal quality and there exists recent successful downlink
transmission before the link failure, that the cause of link failure is an uplink coverage
hole; and
determining, when a measurement report has not been triggered, there exists no
neighboring cell with good signal quality and there exists no recent successful
downlink transmission before the link failure, that the cause of link failure is an
uplink coverage hole and the downlink is unknown.
8. An apparatus for analyzing a cause of link failure, comprising:
a first processing unit configured to determine, when link failure occurs, detailed
triggering information causing the link failure;
a second processing unit configured to analyze a cause of link failure according to
the detailed triggering information causing the link failure; and
a first transmitting unit configured to transmit the cause of link failure obtained
by analysis to a network side.
9. The apparatus according to claim 8, wherein when the detailed triggering
information causing the link failure is a physical layer problem, the second processing
unit is configured to:
determine, when a measurement report has been triggered, that the cause of link
failure is a handover configuration problem;
determine, when a measurement report has not been triggered and there exist
neighboring cells with good signal quality, that the cause of link failure is a handover
configuration problem; and
determine, when a measurement report has not been triggered and there exists no
neighboring cell with good signal quality, that the cause of link failure is a coverage
hole.
10. The apparatus according to claim 9, wherein the second processing unit is
further configured to determine, when a measurement report has not been triggered,
there exists no neighboring cell with good signal quality, that the cause of link failure

is a downlink coverage hole, when there exists recent successful uplink transmission
before the link failure, and determine that the cause of link failure is a downlink
coverage hole and the uplink is unknown, when there exists no recent successful
uplink transmission before the link failure.
11. The apparatus according to claim 8, wherein when the detailed triggering
information causing the link failure is a random access problem of a medium access
control layer, the second processing unit is configured to:
determine, after indication of failure of a random procedure of a medium access
control layer is received, that the cause of link failure is an uplink problem associated
with the random procedure of a medium access control layer.
12. The apparatus according to claim 8, wherein when the detailed triggering
information causing the link failure is a radio link control layer transmission problem,
the second processing unit is configured to:
determine, when a measurement report is triggered and is not transmitted
successfully, that the cause of link failure is a handover configuration problem;
determine, when a measurement report is triggered and is transmitted successfully
and a handover completion message is not transmitted successfully, that the cause of
link failure is a handover configuration problem;
determine, when a measurement report has not been triggered and there exist
neighboring cells with good signal quality, that the cause of link failure is a handover
configuration problem;
determine, when a measurement report has not been triggered, there exists no
neighboring cell with good signal quality and there exists recent successful downlink
transmission before the link failure, that the cause of link failure is an uplink coverage
hole; and
determine, when a measurement report has not been triggered, there exists no
neighboring cell with good signal quality and there exists no recent successful
downlink transmission before the link failure, that the cause of link failure is an
uplink coverage hole and the downlink is unknown.
13. A method for analyzing a cause of link failure, comprising:
acquiring a cause of link failure transmitted by a user side; and
determining a cause of link failure, according to the acquired cause of link failure,
or according to the acquired cause of link failure in combination with a measurement
result.
14. A method of network optimization, comprising:
acquiring a cause of link failure transmitted by a user side;
determining a cause of link failure, according to the acquired cause of link failure,
or according to the acquired cause of link failure in combination with a measurement
result; and
optimizing a network according to the determined cause of link failure.

15. An apparatus for analyzing a cause of link failure, comprising:
a third processing unit configured to acquire a cause of link failure transmitted by
a user side; and
a fourth processing unit configured to determine a cause of link failure, according
to the acquired cause of link failure, or according to the acquired cause of link failure
in combination with a measurement result.
16. An apparatus of network optimization, comprising:
a fifth processing unit configured to acquire a cause of link failure transmitted by
a user side; and
a sixth processing unit configured to determine a cause of link failure, according
to the acquired cause of link failure, or according to the acquired cause of link failure
in combination with a measurement result; and
a first optimizing unit configured to optimize a network according to the
determined cause of link failure.
17. A method for analyzing a cause of link failure, comprising:
determining, when link failure occurs, detailed triggering information causing the
link failure; and
transmitting the detailed triggering information, as a cause of link failure, to a
network side.
18. An apparatus for analyzing a cause of link failure, comprising:
a seventh processing unit configured to determine, when link failure occurs,
detailed triggering information causing the link failure; and
a second transmitting unit configured to transmit the detailed triggering
information, as a cause of link failure, to a network side.
19. A method for analyzing a cause of link failure, comprising:
acquiring detailed triggering information causing the link failure transmitted by a
user side; and
determining a cause of link failure, according to the acquired detailed triggering
information, or according to the acquired detailed triggering information in
combination with a measurement result.
20. An apparatus for analyzing a cause of link failure, comprising:
an eighth processing unit configured to acquire detailed triggering information
causing the link failure transmitted by a user side; and
a ninth processing unit configured to determine a cause of link failure, according
to the acquired detailed triggering information, or according to the acquired detailed
triggering information in combination with a measurement result.
21. A method of network optimization, comprising:

acquiring detailed triggering information causing the link failure transmitted by a
user side;
determining a cause of link failure, according to the acquired detailed triggering
information, or according to the acquired detailed triggering information in
combination with a measurement result; and
optimizing a network according to the determined cause of link failure.
22. An apparatus of network optimization, comprising:
a tenth processing unit configured to acquire detailed triggering information
causing the link failure transmitted by a user side;
an eleventh processing unit configured to determine a cause of link failure,
according to the acquired detailed triggering information, or according to the acquired
detailed triggering information in combination with a measurement result; and .
a second optimizing unit configured to optimize a network according to the
determined cause of link failure.
23. A computer-readable program, wherein when the program is executed in an
apparatus for analyzing a cause of link failure, the program enables a computer to
carry out the method for analyzing a cause of link failure as claimed in any one of
claims 1-7, 13, 17 and 19 in the apparatus.
24. A storage medium in which a computer-readable program is stored, wherein
the computer-readable program enables a computer to carry out the method for
analyzing a cause of link failure as claimed in any one of claims 1-7, 13, 17 and 19 in
an apparatus for analyzing a cause of link failure.
25. A computer-readable program, wherein when the program is executed in an
apparatus of network optimization, the program enables a computer to carry out the
method of network optimization as claimed in claim 14 or 21 in the apparatus.
26. A storage medium in which a computer-readable program is stored, wherein
the computer-readable program enables a computer to carry out the method of
network optimization as claimed in claim 14 or 21 in an apparatus of network
optimization.