CN100397937C

CN100397937C - Wireless link detecting method

Info

Publication number: CN100397937C
Application number: CNB2004100623598A
Authority: CN
Inventors: 郇海滨; 任永铮; 李宝民
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2004-07-06
Filing date: 2004-07-06
Publication date: 2008-06-25
Anticipated expiration: 2024-07-06
Also published as: CN1719926A

Abstract

The present invention discloses a wireless link detecting method which comprises the following steps: when a private channel is converted from a link building state to a multi-frame link building state, a primitive is sent out; whether the private channel receives the primitive or not from the period that channel activation confirmation is received to the period that channel release confirmation is received is detected so as to determine the normality of the uplink and the downlink directions of the private channel. Thereby, the wireless link detecting method of the present invention can simultaneously detect the normality of the uplink and the downlink directions of the private channel, and can further detect the normality of the uplink and the downlink directions of a public channel.

Description

Wireless link detection method

Technical Field

The present invention relates to a method for detecting a radio link in a communication system.

Background

In the field of Communications, a manner of transmitting data through a wireless link is widely applied, for example, in a Global System for Mobile Communications (GSM). The GSM system mainly includes: a Mobile Station (MS), a Base Station Subsystem (BSS), a Network and Switching Subsystem (NSS), and an Operation and Maintenance Center (OMC). Wherein,

the MS is used for receiving and transmitting mobile user requests and information; NSS is used to manage communications between mobile subscribers; the BSS is responsible for allocating and managing the transmission path between the MS and the NSS, in particular the radio link between the MS and other devices of the GSM; the OMC is used for carrying out configuration management and maintenance operation on the BSS.

The BSS further includes a Base Transceiver Station (BTS) and a Base Station Controller (BSC). Wherein,

the BTS is a wireless transceiver serving a cell and is used to establish a connection with the MS through a wireless link; the BSC is responsible for wireless network management, wireless resource management and monitoring management of wireless base stations, controls the management of establishing, connecting and removing a wireless link between the MS and the BTS, and controls and completes the switching, transmission and calling of the MS.

The information transmission flow of the GSM is as follows:

step 10) the MS sends an access request to the BTS through a common channel;

step 11) after receiving the access request in the uplink direction of the public channel, the BTS further sends the information to the BSC;

step 12) after the BCS distributes a special channel for the communication and sends the distributed special channel information to the MS through the BTS according to the access request sent by the BTS;

step 13) the BTS informs the MS of the information of the special channel distributed to the communication from the BSC to the downlink of the public channel;

step 14) the MS receives the dedicated channel information distributed for the communication in the downlink direction of the common channel;

step 15) the MS can perform call signaling interaction through the dedicated channel.

As can be seen from the above, the wireless link of the GSM system is divided into a common channel and a dedicated channel according to functions, and the dedicated channel is used for performing interaction of actual call signaling; the common channel is used to transmit information prior to actual call signaling. Whether the common channel or the dedicated channel is divided into two directions, one is a channel in a downlink direction, such as a channel for transmitting information to the MS by the BTS; the other is the channel in the uplink direction, i.e., the channel on which the MS sends information to the BTS.

The quality of the radio link directly affects the service capability and performance of GSM, so an effective radio link detection method is very necessary to timely detect the system problem and improve the system maintainability.

The existing wireless link detection method is that a signal is transmitted at a BTS side, an actual output value of the transmitted signal is measured, the actual output value is compared with an expected output value, if the comparison result is equal, the signal is normal, otherwise, the signal is abnormal. Since the prior art adopts the method of transmitting signals at the BTS side, only whether the wireless link is normal in the downlink direction can be detected.

Since there is no reference value in the uplink direction, that is, after receiving the signal transmitted by the MS, the BTS cannot know how large the MS expects the transmitted signal, it cannot detect whether the radio link in the uplink direction is normal, that is, the prior art can only detect whether the dedicated channel or the common channel is normal in the downlink direction.

Only when the dedicated channel is normal in the downlink direction and also normal in the uplink direction, it can be indicated that the dedicated channel is normal, and the prior art cannot detect whether the dedicated channel is normal in the uplink direction, that is, cannot detect whether the dedicated channel is normal. And in the same way, the detection of whether the common channel is normal or not can not be realized.

Even if the prior art can realize the detection of the uplink direction of the dedicated channel, the determination of whether the dedicated channel is normal requires the detection of whether the uplink direction and the downlink direction are normal, and the judgment is carried out by considering the detection result of the uplink direction and the detection result of the downlink direction, so that the conclusion is reached.

Disclosure of Invention

The problem to be solved by the present invention is to provide a method for detecting a radio link, which can detect whether a radio link in the uplink and downlink directions of a dedicated channel is normal or not at the same time.

In order to solve the above problems, the technical solution of the wireless link detection method of the present invention is:

a method for radio link detection, comprising the steps of:

when the dedicated channel is converted from the link establishment in-process state to the link establishment completion state, the learning link establishment completion module sends the primitive;

and detecting whether the signaling processing module receives the primitive within the period from the special channel receiving the channel activation confirmation to the channel release confirmation so as to determine whether the uplink and downlink directions of the special channel are normal.

The wireless link detection method of the invention also comprises the following steps:

setting the values of a detection base number, an abnormal threshold and a recovery threshold, wherein,

the detection base number is used for representing the number of times of detection,

the abnormal threshold is used for representing the lowest limit value of the abnormal rate after the detection of the detection base number times, if the rate exceeds the lowest limit value, the abnormal rate is represented by the special channel,

the recovery threshold is used for representing the highest value to which the abnormal rate is reduced after the abnormal rate is generated, and if the abnormal rate is reduced to the highest value, the special channel is eliminated;

after the detection of the detection base number times, counting the abnormal rate of the special channel;

triggering alarm processing and carrying out fault self-repairing processing when the ratio reaches the value of the abnormal threshold;

after the alarm processing is triggered, counting the abnormal rate of the special channel again at intervals;

and triggering alarm disappearance treatment when the abnormal rate of the special channel is reduced to the value of a recovery threshold.

counting the random access and the switching access of the public channel;

if random access exists, the uplink and downlink directions of the public channel are normal;

if only switching access is carried out but random access is not carried out, the uplink direction of the public channel is abnormal and the downlink direction of the public channel is normal;

and if the switching access and the random access are not available, the downlink direction of the common channel is abnormal.

The invention also provides a wireless link detection method, which comprises the following steps:

setting a reference value;

acquiring the levels of the dedicated channel in the uplink direction and the downlink direction;

finding the difference between the levels in the uplink direction and the downlink direction;

the fact that the absolute value of the difference between the levels is not greater than the reference value indicates that the dedicated channel is normally detected this time.

setting values of an alarm threshold and a recovery threshold, wherein,

the alarm threshold is used for representing the lowest limit value of the abnormal rate in a preset time period, and if the rate reaches the lowest limit value, the abnormal rate is represented by the special channel;

counting the times of detecting the abnormity of the dedicated channel;

calculating the abnormal rate of the dedicated channel;

triggering alarm processing when the ratio reaches the alarm threshold;

after the alarm processing is triggered, counting and calculating the abnormal rate of the special channel again at a time interval;

if the ratio is reduced to a recovery threshold, alarm disappearance processing is triggered

counting the random access and the switching access of the public channel;

Compared with the prior art, the wireless link detection method has the beneficial effects that:

the technical scheme of the wireless link detection method of the invention is that when a dedicated channel is converted from a chain establishment in-progress state to a chain establishment completion state, a primitive is sent, and whether the primitive is received or not is detected in the period from the receiving of a channel activation confirmation to the channel release confirmation of the dedicated channel. If the primitive is received, the detection that the dedicated channel is normal is indicated; otherwise, the special channel abnormity is detected. It is possible to detect whether the uplink and downlink directions of the dedicated channel are normal.

The other wireless link detection method provided by the invention judges the abnormal condition of the special channel caused by the imbalance of the uplink and downlink directions by counting and calculating the difference value of the levels of the uplink and downlink directions of the special channel.

Finally, the wireless link detection method of the invention judges whether the common channel is normal in the uplink and downlink direction by counting the times of the switching access and the random access on the common channel and analyzing whether the switching access and the random access exist.

Drawings

FIG. 1 is a flow chart of information transmission for GSM;

FIG. 2 is a flow chart of a radio link detection method of the present invention;

FIG. 3 is a flow chart of a further refinement of the detection of the normal condition of the dedicated channel;

FIG. 4 is a flow chart for detecting a common channel normal condition;

fig. 5 is a flow chart of detecting a dedicated channel due to an imbalance in the uplink and downlink directions;

fig. 6 is a further improved flow of detecting dedicated channels due to imbalance in the uplink and downlink directions;

FIG. 7 is a detection diagram of an embodiment of the radio link detection method of the present invention;

fig. 8 is a schematic diagram of the presence of an embodiment of the radio link detection method of the present invention.

Detailed Description

As shown in fig. 2, the wireless link detection method of the present invention includes the following steps:

step 20) when the dedicated channel is converted from the chain establishment in-progress state to the chain establishment completion state, sending a primitive;

step 21) detecting whether the primitive is received in the period from the channel activation confirmation to the channel release confirmation of the dedicated channel;

if the primitive is received, the detection that the dedicated channel is normal is represented; otherwise, the special channel abnormity is detected.

The state in the process of establishing the link refers to the time from the beginning of establishing the link to the completion of establishing the link after the special channel is activated; the link setup complete state refers to the interaction of actual call signaling between mobile devices. When the state is converted to the link establishment completion state from the link establishment in-process state, the link establishment is completed, and the link establishment process needs interaction between two parties, namely, the link establishment primitive transmitted in the downlink direction is received, and the link establishment confirmation primitive transmitted in the uplink direction is received, so that the link establishment is completed successfully. Since the link establishment primitive transmitted in the downlink direction has been received, it indicates that the downlink direction is normal; the method comprises the steps that a link establishment confirmation primitive transmitted in the uplink direction is received to indicate that the uplink direction is normal, so the primitive is sent when the link establishment is completed, whether the primitive is received or not is detected in the period from the channel activation confirmation to the channel release confirmation, if the primitive is received, the link establishment is successfully completed and the primitives are normal in the uplink direction and the downlink direction, otherwise, the link establishment is not successfully completed, namely, at least one direction is abnormal.

Because a conclusion is obtained through one-time detection to show whether the dedicated channel is abnormal or not reasonably, the dedicated channel is abnormal when the dedicated channel is detected alone, and the dedicated channel is normal when the dedicated channel is detected alone, so that the situation that the dedicated channel is abnormal in the detection times can be judged by setting one detection time and counting the abnormal situation in the detection times. Therefore, further, the radio link detection method of the present invention measures whether the dedicated channel is normal by detecting the base number, the threshold and the recovery threshold, wherein,

the detection base is used for representing the number of times of detection;

the abnormal threshold is used for representing the lowest limit value of the abnormal rate after the detection of the detection base number times, and if the rate exceeds the lowest limit value, the abnormal rate is represented by the special channel;

as shown in fig. 3, the radio link detection method further includes the following steps:

step 30) setting values of a detection base number, an abnormal threshold and a recovery threshold;

step 31) after the detection of the detection base number times, counting the abnormal rate of the special channel;

step 32) determining whether the ratio reaches an abnormal threshold value;

if the value of the abnormal threshold is not reached, the special channel is normal, otherwise, the following steps are executed,

step 33) triggering alarm processing and carrying out fault self-repairing processing;

step 34), after the alarm processing is triggered, counting the abnormal rate of the special channel again at intervals;

step 35) determining whether said ratio falls below a recovery threshold value;

if the judgment result is positive, executing the step 36) to trigger the alarm disappearance processing;

if the determination result is negative, step 34) is repeatedly executed.

For the dedicated channel, if the uplink and downlink direction levels are not balanced, the dedicated channel will be abnormal, and the method for detecting the abnormal dedicated channel caused by this reason is shown in fig. 5, and the method for detecting the radio link further includes the following steps:

step 50), setting a reference value, wherein the reference value is used for measuring whether the dedicated channel is normal;

step 51) obtaining the levels of the dedicated channel in the uplink direction and the downlink direction;

step 52) obtaining the difference between the levels of the uplink direction and the downlink direction;

step 53) determining whether the absolute value of the difference between the levels is greater than a reference value;

if the judgment result is positive, the special channel is detected to be abnormal;

if the judgment result is negative, the detection of the dedicated channel is normal.

Similarly, it is not reasonable to determine whether the dedicated channel is normal or not by only one detection, so further, it is determined whether to trigger the alarm process and the alarm disappearance process by the alarm threshold and the recovery threshold, wherein,

the alarm threshold is used for representing the lowest limit value of abnormal rate in a preset time period, and if the rate reaches the lowest limit value, the alarm threshold represents that the special channel is abnormal;

as shown in fig. 6, the radio link detection method further includes the following steps:

step 60) setting values of an alarm threshold and a recovery threshold;

step 61) counting the times of detecting the abnormity of the dedicated channel;

step 62) calculating the abnormal rate of the dedicated channel;

step 63) judging whether the ratio reaches the alarm threshold;

if the alarm threshold is not reached, the special channel is normal; otherwise, the following steps are executed,

step 64) triggering alarm processing;

step 65) counting and calculating the abnormal rate of the special channel again at a certain time interval;

step 66) determining whether the ratio falls below a recovery threshold;

if the judgment result is negative, step 65) is executed, otherwise step 67) is executed to trigger the alarm disappearance processing.

Further, the radio link detection method of the present invention can also be used to detect whether the common channel is normal. As shown in fig. 4, the radio link detection method further includes the following steps:

step 40) counting the random access and the switching access of the public channel;

step 41) judging the conditions of random access and switching access,

if random access exists, the common channel is normal in the uplink and downlink directions;

if only switching access is carried out but random access is not carried out, the uplink direction of the public channel is abnormal but the downlink direction of the public channel is normal;

and if the random cut-in and the random access are not available, the downlink direction of the common channel is abnormal.

For the public channel, if the uplink direction is abnormal, the public channel does not have random access; if the downlink direction is abnormal, the public channel does not have switching access, and even does not have random access; random access can only be achieved if the uplink and downlink directions are normal.

The following description will be made taking radio link detection between the BTS and the MS in GSM as an example.

In GSM, BSCs are used to establish, connect, release and manage radio links. This example is used to detect the dedicated channel of the Link Access Procedure (LAPDm) layer. As shown in fig. 7, the specific process is as follows:

BSC sends channel activation request to signal processing module of BTS;

after receiving the channel activation request, the signaling processing module sends a channel activation confirmation to the BSC;

so that the dedicated channel between the BTS and the MS is activated.

After the special channel is activated, the following steps are executed:

MS sends link establishing primitive (such as SABME) to LAPDm layer module of LAPDm layer wireless link;

the LAPDm layer module sends a confirmation primitive (such as UA) to the MS;

MS sends connection primitive (I) to LAPDm layer module;

when the LAPDm layer wireless link is converted from a link establishment in-progress state (namely the sending of a link establishment primitive SABME) to a link establishment completion state (namely a call signaling flow is entered), the LAPDm layer module sends a primitive (such as LAPDm Est Done) to the signaling processing module;

entering a call signaling flow, namely, carrying out signaling interaction;

after the signaling interaction is finished, the BSC sends a channel release primitive (such as RF ChannelRelease) to the signaling processing module;

the signaling processing module sends a Channel release acknowledgement primitive (e.g., RF Channel Rel Ack) to the BSC.

The dedicated channel established so far is released.

The signaling processing module detects whether a primitive (such as LAPDm Est Done) sent by the LAPDm layer module when the LAPDm layer wireless link is converted from a link establishment in-progress state to a link establishment completion state is received or not in the period from the time of receiving the channel activation confirmation to the time of receiving the channel release confirmation, if the primitive is received, the uplink and downlink directions of the dedicated channel are normal during the detection, otherwise, the dedicated channel is abnormal.

The link establishment in-process state refers to that the MS sends SABME to the LAPDm layer module until the LAPDm layer module receives I sent by the mobile equipment (link establishment is completed). The link establishment completion state indicates that the link establishment is successfully completed and the interactive process of the call signaling is started.

If the uplink direction is abnormal and the downlink direction is normal, after the special channel is activated, the LAPDm layer module cannot receive the SABME, the chain building cannot be completed, so that the BSC sends a channel release request after a period of time, and the LAPDm layer module sends a channel release confirmation;

if the downlink direction is abnormal and the uplink direction is normal, after the dedicated channel is activated, the LAPDm layer module receives the SABME, the LAPDm layer module sends UA to the MS after receiving the SABME, and the MS cannot receive the UA in the downlink direction, so that the chain establishment cannot be successfully completed, and the BSC sends a channel release request after a period of time;

if the uplink and downlink directions are abnormal, the link establishment can not be successfully completed, and the BSC sends a channel release request after a period of time.

As can be seen from the above description, the BTS does not receive the primitive sent when the link establishment state (i.e., sending of the link establishment primitive SABME) is changed to the link establishment state (i.e., entering the call signaling flow) because the link establishment cannot be completed successfully.

If the primitive is received, the uplink and downlink directions are normal, otherwise, at least one direction is abnormal.

As shown in fig. 8, the LAPDm layer module does not receive the link establishment primitive (SABME) sent by the MS, and the signaling processing module also does not receive the primitive sent by the LAPDm layer module, which indicates that the link establishment is not successful, and there is no interaction of the actual signaling.

The setting of the detection base number, the abnormal threshold and the recovery threshold is determined according to the condition of the telephone traffic of the current cell. For a cell with a large traffic volume, the detection base number may be configured to be larger, and the abnormal threshold and the recovery threshold may be configured to be smaller, for example: the detection base number is 20, the abnormal threshold is 60% and the recovery threshold is 40%; for a cell with smaller traffic, the detection base number may be configured to be smaller, and the abnormal threshold and the recovery threshold may be configured to be larger, for example: the detection base number is 10, the anomaly threshold is 80% and the recovery threshold is 50%.

In order to prevent the radio link status from oscillating repeatedly between normal and abnormal, the recovery threshold value should be lower than the abnormal threshold value.

In this example, the detection base number is set to 40, the abnormal threshold is set to 60%, the recovery threshold is set to 40%, and the occurrence of the dedicated channel is counted in units of time slots. For example, a time slot is configured as a half-rate traffic channel type, so that two half-rate physical channels exist in the time slot for communication on a dedicated channel, and when the sum of the times that the two physical channels occupy (each time the channel is occupied for one detection) in the time slot reaches 20 × 2, i.e. 40, which means that the detection times reaches the detection base 40, it is possible to count whether the dedicated channel is normal or not.

The channel occupation occurring on the time slot is numbered as 1, 2 and 3 in sequence according to the time sequence. . . 40. 41, 42, when the channel occupation is accumulated to the 40 th time, the detection base number is reached, and the statistical number is the abnormal rate in the 40 times of channel occupation; then, 1 time of channel occupation is carried out, the number is 41, and the situation of channel occupation occurring in 40 times of 2-41 times is counted; channel occupation occurs for 1 time again, the number is 42, and the abnormal rate in channel occupation of 3-42 times is counted; and so on. If the time slot half-rate physical channel is continuously occupied, statistics is only carried out on the channel occupation of the last 40 times each time, namely a detection window which continuously moves forwards exists, and the fact that the statistic information reflects the latest state is guaranteed. For example, if the detected dedicated channel: 1-8, 9-20, 21-35, 36-39 and 40, counting that (8+15+1)/40 is equal to 60% in 40 detections in 1-40 times, and triggering alarm processing and performing fault self-repairing processing when the value reaches an abnormal threshold; 41-47 channel occupation is normal for the next 7 times, the ratio of abnormality in 40 channel occupation in 8-47 times is counted to be (1+15+1)/40 and equal to 42.5% at the 47 th time, the recovery threshold is not reached to 40%, and no further processing is carried out; and if the channel occupation 48 is normal after 1 time, counting that the abnormal ratio in 40 occupation of 9-48 times is (15+1)/40 and is equal to 40 percent, and reaching the recovery threshold of 40 percent, triggering the alarm disappearance treatment.

For the dedicated channel of the wireless link, if the levels in the uplink direction and the downlink direction are not balanced, that is, there is a large difference between the uplink coverage and the downlink coverage, a large number of abnormal calls can be caused, and only part of the calls are normal. The detection method for the abnormal condition of the dedicated channel caused by this reason is shown in fig. 5.

In this example, a reference value of 30dbm is set;

extracting the levels of the uplink direction and the uplink direction of the dedicated channel from a measurement report reported to the BSC by the BTS;

calculating the difference between the levels in the uplink direction and the downlink direction;

if the absolute value of the difference between the levels is within a reference value, i.e. 30dbm, it indicates normal, otherwise it indicates abnormal.

When calculating the absolute value of the difference between the uplink and downlink levels, the action of power control needs to be compensated, and the reference of uplink and downlink comparison is adjusted to 0 power level, for example: the uplink direction level is-60 dbm, the MS power level is 4, the downlink direction level is-70 dbm, the BTS power level is 3, the uplink direction decision level is-60 +2 x 4 and is equal to-52 dbm, the downlink direction decision level is-70 +2 x 3 and is equal to-64 dbm, the difference between the uplink direction level and the downlink direction level is-64- (-52) and is-12 dbm, which represents that the downlink is weaker than 12dbm, and the 12dbm is less than 30dbm, so the detection is in the effective range of uplink and downlink balance, and the detection result is normal.

The setting of the alarm threshold and the recovery threshold is determined according to the traffic of the current cell, and in this example, the alarm threshold and the recovery threshold are respectively set to be 80% and 50%.

Whether the uplink and downlink direction level is balanced is for the whole carrier frequency, and time slots and channels are not distinguished, so each measurement report reported by the carrier frequency is analyzed, in the embodiment, 0:00 per night is adopted, the uplink and downlink direction level data accumulated in the whole day is counted, the ratio is checked, and if the uplink and downlink direction level reaches 80% of the set alarm threshold, the alarm processing is triggered. And once the alarm appears, the condition of the unbalanced level of the uplink and the downlink directions is counted again every hour, and if the ratio is reduced to 50 percent of the recovery threshold, the alarm disappearance processing is triggered; otherwise, no further processing is performed.

For a common channel of a wireless link, if a BTS can successfully receive a random access message reported by an MS, the uplink and downlink directions of the common channel are normal; if only a switching access message but no random access message can be received in a time period, indicating that the uplink direction of the public channel is abnormal and the downlink direction is normal; if the message of switching access and the message of random access do not exist in a time period, the fact that the uplink direction and the downlink direction of the public channel are abnormal is indicated. According to this principle, the common channel is detected using the procedure shown in fig. 4. And in a time period, counting the times of switching access and random access to obtain a conclusion. The selection of the specific detection time period (including the detection start time and the detection end time, and the detection time period length) needs to comprehensively consider the general traffic situation of the current cell and the living habits of the user. For example: the amount of traffic may be very small late at night, so this period of time is not generally considered a detection period. The time period with large telephone traffic is selected for statistics, so that the real situation of the common channel can be reflected.

In summary, the radio link detection method of the present invention can detect whether the dedicated channel is normal or not, and can detect whether the common channel is normal or not.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and embellishments can be made without departing from the principle of the wireless link detection method of the present invention, and these modifications and embellishments should also be regarded as the protection scope of the wireless link detection method of the present invention.

Claims

1. A method for radio link detection, comprising the steps of:

when the dedicated channel is converted from the link establishment in-progress state to the link establishment completion state, the module which acquires the link establishment completion sends the primitive;

2. The radio link detection method of claim 1, further comprising the steps of:

3. The radio link detection method according to claim 1 or 2, further comprising the steps of:

counting random access and switching access of a common channel;

4. A method for radio link detection, comprising the steps of:

setting a reference value;

5. The radio link detection method according to claim 4, further comprising the steps of:

setting values of an alarm threshold and a recovery threshold, wherein,

counting the times of detecting the abnormity of the dedicated channel;

calculating the abnormal rate of the dedicated channel;

triggering alarm processing when the ratio reaches the alarm threshold;

and if the ratio is reduced to a recovery threshold, triggering alarm disappearance treatment.

6. The radio link detection method according to claim 4 or 5, further comprising the steps of:

counting random access and switching access of a common channel;