CN101783975B - Method, device and system for measuring distance in communication network - Google Patents
Method, device and system for measuring distance in communication network Download PDFInfo
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Abstract
The invention discloses a method, a device and a system for measuring distance in a communication network. The method comprises that: a slave node sends a rough distance measurement signal of which the rate is lower than the service rate to a master node, and requests the master node to return a rough distance measurement response signal to the slave node; and after the rough distance measurement response signal returned by the master node is received, a rough distance measurement result is acquired according to the rough distance measurement response signal, and corresponding distance measurement operation is carried out. The invention adopts an implementation scheme that the distance is measured by a low-rate rough distance measurement signal, so the service transmission process of other nodes is not needed to be paused or interrupted in the process of implementing distance measurement. Besides, the distance measurement scheme also can reduce the cost of distance measurement processing.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a ranging technology in a communication network.
Background
A Gigabit-capable Passive Optical Network (GPON) provides a point-to-multipoint physical topology, as shown in fig. 1, and specifically includes: an OLT (Optical line terminal) 32, an ODN (Optical Distribution Network) 31, and a plurality of ONUs (Optical Network units) 30. The ONU shares optical fiber resources and an OLT port; the ODN passively connects an OLT and one or more ONUs.
In GPON, the downlink direction is from OLT to ONU, the uplink direction is from ONU to OLT, and corresponding uplink and downlink signals are all sent in a framed manner, which are referred to as downlink frame and uplink frame, respectively. In the process of sending the downlink frame, the OLT calculates the burst length and the burst position of each ONU in each frame and sends the burst length and the burst position to the ONU, namely, the starting position and the ending position of each burst in the uplink frame are defined in the downlink frame sent to the ONU by the OLT. Thus, the ONU can perform burst transmission according to the position of the received downlink frame.
In order to avoid transmission collision between different ONUs, the ONUs need to perform ranging operation to test the equalization delay from the ONUs to the OLT, so that each ONU can transmit bursts according to pointers defined in a downlink frame (i.e. the start and end positions of each burst in an uplink frame) by using the equalization delay as a reference, and it can be ensured that the bursts transmitted by each ONU do not collide after the bursts transmitted by the ONUs reach the OLT.
Specifically, the ONU may specifically execute a corresponding ONU ranging operation process when initialization is performed or a logical distance between the ONU and the OLT changes, so as to obtain an equalization delay between the OLT and the ONU, so that the ONU adjusts an uplink frame clock according to the equalization delay.
In the process of the ONU performing the ranging operation, since the OLT does not know the location of the ONU, in order to prevent the data transmitted by the ONU from interfering with the ONU which normally operates, the OLT issues an instruction to cause the ONU which normally operates to suspend the transmission of a plurality of frame data.
In the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art:
if the ONU is located in the home of the user (i.e. using the ONT, the fiber network terminal, which is described below for convenience of description, or using the ONU for explanation), the power-on or initialization process of the ONU will be very frequent. Frequent powering-on or initialization of the ONU will cause frequent execution of corresponding ranging operations, which further causes frequent interruption of data transmission of the ONU working normally, thereby affecting the data transmission process of the ONU working normally.
Meanwhile, except for star-type or tree-type networks such as GPON, other networks have the problem that the corresponding ranging process affects the data transmission of other nodes.
Disclosure of Invention
Embodiments of the present invention provide a ranging method, apparatus, and system in a communication network, so as to avoid affecting a normal service data transmission process of other nodes when a node in a channel network performs a ranging operation.
A method of ranging in a communication network, comprising:
in the initial uplink signal reference position, the slave node sends a rough ranging signal with a rate lower than the service rate to the master node, and requests the master node to return a rough ranging response signal to the slave node, wherein the initial uplink signal reference position is a position selected from downlink signals sent to the slave node from the master node according to a preset rule;
and receiving a rough ranging response signal returned by the main node, and obtaining a rough ranging result according to the rough ranging response signal.
A ranging apparatus in a communication network, comprising:
a rough ranging signal sending unit, configured to send a rough ranging signal with a rate lower than a service rate to a master node at an initial uplink signal reference position, and request the master node to return a rough ranging response signal to the slave node, where the initial uplink signal reference position is a position selected from downlink signals sent from the master node to the slave node according to a predetermined rule;
and the rough ranging unit is used for receiving a rough ranging response signal returned by the main node, obtaining a rough ranging result according to the rough ranging response signal and realizing rough ranging.
A method of ranging in a communication network, comprising:
the master node receives a rough ranging signal which is sent by the slave node and has a rate lower than the service rate;
and the master node returns a rough ranging response signal to the slave node, wherein the rough ranging response signal comprises a rough ranging result.
A ranging apparatus in a communication network, comprising:
a coarse ranging signal receiving unit for receiving a coarse ranging signal transmitted from a node at a rate lower than a traffic rate;
a coarse ranging result sending unit, configured to return a coarse ranging response signal to the slave node after the coarse ranging signal receiving unit receives the coarse ranging signal, where the coarse ranging response signal includes a coarse ranging result.
A ranging system in a communication network comprises a master node and a slave node, wherein the master node comprises a ranging device in the second communication network, and the slave node comprises a ranging device in the first communication network.
The technical scheme provided by the embodiment of the invention can be seen that the low-speed rough ranging signal is adopted for ranging, so that the service transmission process of other nodes does not need to be suspended or interrupted in the ranging process. Moreover, the distance measurement scheme provided by the embodiment of the invention can also reduce the cost for realizing distance measurement processing.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.
Fig. 1 is a schematic structural diagram of a GPON network in the prior art;
fig. 2 is a schematic diagram of a coarse ranging process according to an embodiment of the present invention;
FIG. 3 is a diagram illustrating a format of a coarse ranging signal according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a precise ranging process according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of an apparatus and system according to an embodiment of the present invention;
FIG. 6 is a first schematic structural diagram of a system according to an embodiment of the present invention;
FIG. 7 is a second schematic structural diagram of a system according to an embodiment of the present invention;
fig. 8A is a schematic diagram of a transmitter in the prior art;
fig. 8B is a schematic structural diagram of a system provided in the embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the ranging scheme in the communication network provided in the embodiment of the present invention, the slave node may communicate with the master node to implement a corresponding ranging process, and specifically, the ranging process that the slave node needs to execute in the process may include: the slave node sends a rough ranging signal lower than the service rate to the master node to request the master node to return a rough ranging response signal to the slave node; after receiving the coarse ranging response signal returned by the master node, the slave node may obtain the coarse ranging result in the coarse ranging response signal to implement the corresponding coarse ranging.
In the above coarse ranging process performed by the slave node, the corresponding coarse ranging signal is sent at an initial uplink reference position, where the initial uplink reference position is determined according to a reference position of a downlink signal sent to the slave node by the master node, that is, a position is selected from the downlink signal as the initial uplink reference position according to a predetermined rule, for example, the corresponding initial uplink reference position may be determined by locking a header of a downlink frame in a GPON system, or another position in the downlink signal may be selected as the initial uplink reference frame position according to a predetermined rule; the predetermined rule may be preset in each slave node, or may be sent to the slave node via a downlink signal (e.g., the slave node is informed of the corresponding initial uplink reference position via some indication in the downlink signal).
Further, a corresponding coarse ranging signal transmitter may be specifically provided in the slave node, and the coarse ranging signal transmitter transmits the coarse ranging signal, and the coarse ranging signal transmitter is not used for transmitting traffic, but is exclusively used for transmitting the coarse ranging signal; alternatively, in the slave node, a traffic transmitter for transmitting traffic may be used to transmit the coarse ranging signal. If the rough ranging signal is sent by the rough ranging signal transmitter, the rough ranging signal transmitter and the service transmitter may transmit signals with different wavelengths.
In the slave node, the corresponding transmission power for transmitting the coarse ranging signal may be lower than the transmission power for transmitting the traffic. If the slave node adopts a separate coarse ranging signal transmitter, on one hand, because the coarse ranging signal rate is low, the receiving sensitivity can be very low, and the slave node can adopt lower power to transmit the coarse ranging signal; on the other hand, the coarse ranging signal transmitter cost can be reduced by adopting lower transmission power. If the slave node transmits the coarse ranging signal using the traffic transmitter, the use of as low a transmit power as possible can reduce the impact on the normal traffic transmission of other slave nodes.
Selection of the coarse ranging signal transmit power, the corresponding slave node may:
1) and determining the transmission power of the rough ranging signal according to the received power of the downlink signal transmitted by the main node. The specific implementation mode is shown in the following content.
2) The transmission power of the coarse ranging signal may be determined based on preset information. If in some applications the slave node allows to configure some information, the transmission power of the coarse ranging signal of the slave node can also be set directly according to the actual situation of the network.
In the embodiment of the invention, when the slave node sends the rough ranging signal, one random delay can be specifically adopted to send the rough ranging signal, so that the probability that a plurality of slave nodes send the rough ranging signal at the same time is reduced, and the collision among the rough ranging signals is avoided.
Optionally, in this embodiment of the present invention, the slave node may further perform a corresponding precise ranging operation to obtain a precise ranging result, where the corresponding precise ranging operation is implemented on the basis of the rough ranging, and the process may specifically include: firstly, the slave node determines the frame head position of an uplink frame according to the rough distance measurement result in the received rough distance measurement response signal, and determines the position of a precise distance measurement channel according to the frame head position; then the slave node also sends an accurate ranging signal equal to the service rate through the accurate ranging channel to request the master node to return an accurate ranging result to the slave node; and finally, after receiving the accurate ranging result sent by the master node, the slave node can complete the corresponding accurate ranging process to realize the accurate ranging operation.
In the precise ranging process, the corresponding process of sending the precise ranging signal equal to the service rate may specifically send the precise ranging signal with the length smaller than the length of the precise ranging channel at the selected position in the precise ranging channel, where the selected position needs to ensure that the precise ranging signal sent by the slave node does not exceed the range of the precise ranging channel determined by the master node under the rough ranging precision, and the rate and power of the corresponding precise ranging signal are the same as the rate and power of sending the service.
In the ranging scheme in the communication network provided in the embodiment of the present invention, the ranging process performed by the corresponding master node may include: after receiving the coarse ranging signal which is sent by the slave node and is lower than the traffic rate, the master node returns a coarse ranging response signal to the slave node, and the coarse ranging response signal contains a coarse ranging result, so that the slave node can realize corresponding ranging operation.
In order to enable the slave node to realize the accurate ranging operation, the corresponding master node can also send accurate ranging starting information to the slave node through the accurate ranging channel so as to indicate the slave node to return accurate ranging information (the corresponding accurate ranging information is carried in the accurate ranging signal), thereby realizing the corresponding accurate ranging operation; after the master node receives the accurate ranging information sent by the slave nodes, the accurate ranging result is calculated and returned to the corresponding slave nodes, so that the slave nodes can obtain the corresponding accurate ranging result to complete the ranging process.
Optionally, on the master node, a precise ranging channel for performing precise ranging signal transmission may also be set, and only a predetermined low-priority service is allowed to be transmitted in the precise ranging channel; in this scenario, if there is a service transmitted in the precise ranging channel that needs to be currently applied, the master node also needs to control the slave node to stop the service transmitted in the precise ranging channel, so as to ensure reliable implementation of the precise ranging process.
Through the ranging scheme, corresponding ranging operation can be realized in star-shaped or tree-shaped networks such as GPON or EPON (Ethernet passive optical network) and other networks, and the normal service transmission process of other slave nodes can not be influenced by the realization of the corresponding ranging process.
The following takes GPON as an example to describe a specific embodiment of the present invention, and for EPON or other networks, the corresponding implementation manner can be derived by simple reasoning, so detailed descriptions are omitted.
By taking the embodiment of the invention applied to the GPON network as an example, the embodiment of the invention can realize that the data transmission process of other normally working ONUs cannot be influenced when any ONU carries out ranging, thereby improving the data transmission quality of the ONUs, simplifying the design of the OLT, eliminating the limitation of the logic distance difference between the ONUs and the OLT, expanding the coverage range of the system and reducing the network cost.
For the purpose of facilitating an understanding of the embodiments of the present invention, a detailed application of the embodiments of the present invention will be described below with reference to the accompanying drawings. Specifically, the following description will take a main node or a root node of a star or tree as an OLT, and a slave node or a leaf node as an ONU as an example.
Example one
In the first embodiment, a coarse ranging method is mainly used to perform ranging between the ONU and the OLT. In the coarse ranging mode, the ONU may perform coarse ranging by locking a frame header of a downlink and using a low-speed signal with a transmission rate lower than a traffic transmission rate as a coarse ranging signal in an uplink direction.
Referring to fig. 2, the implementation procedure of the corresponding coarse ranging may further include:
the ONU specifically may enter a ranging state at an initialization start stage, or determine to enter a coarse ranging stage according to an instruction sent by the OLT;
the corresponding initial uplink frame header may specifically be a frame header generated by locking a downlink frame header sent by the OLT to the ONU, and for example, the initial uplink frame header may be determined in a phase-locked loop locking phase difference manner;
the corresponding coarse ranging signal mainly includes a frame header part for the OLT to measure the ONU upstream frame header time difference, specifically, the format of the corresponding coarse ranging signal may be as shown in fig. 3, and the transmission rate of the corresponding coarse ranging signal may be 1 Mbit/s. If the ONU is not activated, the sent coarse ranging signal may include ONU serial number information, so that the OLT allocates a corresponding ONU ID (ONU identifier) to the ONU, and further, after the ONU is activated, the OLT controls the operation of the ONU by using the ONU ID to identify different ONUs. That is, in the GPON, when the slave node ONU is initialized (for example, powered on), it needs to be activated, and then the ONU ID needs to be acquired, and ranging can be started after the ONU ID is acquired. If the ONU is already activated, the corresponding ONU serial number information may not be included in the transmitted coarse ranging signal.
The time of the coarse ranging signal sent by the ONU may last for a relatively long period of time (e.g. 2ms, etc.) until the ONU receives the response from the OLT;
optionally, if the ONU initiates the initial ranging, the information carried in the coarse ranging response signal sent by the OLT may further include: OUN ID (ONU identification);
optionally, after the corresponding OLT successfully receives the coarse ranging signal of a certain ONU, an instruction for delaying the start of ranging by another ONU may be issued to avoid collision.
Step 3, the ONU successfully receives the t1 value in the rough ranging response signal sent by the OLT, and calculates the equalization delay according to the t1 value to realize the corresponding rough ranging processing; the corresponding equalization delay refers to that the ONU transmits a signal by delaying the equalization delay for a period of time, so that the transmitted signal can be ensured to be synchronous with the start position of the uplink frame after reaching the OLT.
In the coarse ranging stage, if the coarse ranging signal received by the OLT has an error, it may be indicated that: the rough ranging signals sent by different ONUs collide; or, a fault occurs on the line, resulting in reception errors. If the input optical power of the detected rough ranging signal changes, such as suddenly increases, during the process that the OLT receives the rough ranging signal, the OLT may issue an instruction to delay the ONU performing ranging for a random time to generate the rough ranging signal, so as to avoid collision. If the OLT cannot receive a valid coarse ranging signal within a certain time period, for example, if the OLT receives a signal but has an error code, it may determine that a line has a fault and may alarm.
Example two
In the second embodiment, the method mainly combines the coarse ranging and the precise ranging to perform the ranging process between the ONU and the OLT, that is, the ranging process is sequentially completed by two stages of the coarse ranging and the precise ranging without affecting the service transmission of the slave node which normally works. Specifically, in the first embodiment, after the coarse ranging stage is completed, the OLT opens an upstream precise ranging channel to the ONU, so that the ONU can send a short precise ranging burst at the selected position of the precise ranging channel to perform corresponding precise ranging. At this time, the accuracy of the rough ranging provided in the first embodiment may be as long as it can be ensured that the precise ranging burst does not exceed the range of the precise ranging channel.
Referring to fig. 4, the corresponding ranging process may specifically include:
the ONU specifically may enter a ranging state at an initialization start stage, or determine to enter a coarse ranging stage according to an instruction sent by the OLT;
the corresponding initial uplink frame header may specifically be a frame header generated by locking a downlink frame header sent by the OLT to the ONU, and for example, the initial uplink frame header may be determined in a phase-locked loop locking phase difference manner;
the corresponding coarse ranging signal mainly includes a frame header part for the OLT to measure the ONU upstream frame header time difference, and specifically, the format of the corresponding coarse ranging signal may still be as shown in fig. 3.
The time of the coarse ranging signal sent by the ONU may last for a relatively long period of time (e.g. 2ms, etc.) until the ONU receives the response from the OLT;
if the uplink service exists on the precise ranging channel, the OLT further needs to suppress uplink service transmission on the precise ranging channel so as to facilitate sending of the rough ranging response signal;
if the ranging initiated by the ONU is the initial ranging, the information carried in the accurate ranging signal sent by the OLT may further include: an ONU ID;
the corresponding precise ranging channel may be a channel at a fixed position in an uplink frame of a service sent by the ONU, and the length of the channel is mainly to ensure that a burst sent by the ONU after rough ranging can fall in the precise ranging channel, for example, the length of the channel may be set to 3 us; moreover, when the system is configured with the accurate ranging channel, the system can be configured to transmit some traffic with lower priority of best effort transmission on the channel when the system does not measure the distance through the accurate ranging channel;
optionally, after the corresponding OLT successfully receives the ranging signal of a certain ONU, an instruction for delaying the start of ranging by another ONU may be issued to avoid collision.
And 3, when the ONU successfully receives the t1 value in the accurate ranging signal sent by the OLT, sending confirmation information to the OLT to confirm that the corresponding t1 value is received and confirm that the accurate ranging channel is idle.
Step 4, after receiving the confirmation information of the ONU, the OLT can enter a subsequent accurate ranging stage, namely sending accurate ranging starting information to the ONU;
step 5, after receiving the accurate ranging starting information, the ONU sends accurate ranging information to the OLT through an accurate ranging channel;
specifically, the ONU may calculate a new upstream frame header according to a time difference t1 between the received ONU upstream frame header for performing ranging and the upstream frame header of the system, and further determine the position of the precise ranging channel, so as to send precise ranging information;
specifically, the ONU transmits accurate ranging information in an accurate ranging channel according to the determined new uplink frame header by adopting the power and the rate of the transmission service; further, an accurate ranging signal may be returned to the OLT at a selected location (such as an intermediate location) of the accurate ranging channel to carry corresponding ranging information, where the ranging information may be a PLOAM (physical layer operation administration and maintenance) message, or a received count value may be directly returned; moreover, the length of the corresponding ranging signal needs to be smaller than that of the precise ranging channel, for example, if the length of the corresponding precise ranging channel is 3us, the length of the ranging signal may be 50ns, so that even if the new upstream frame header set according to the value t1 causes the ranging signal to deviate from the center position of the precise ranging channel by 1us, the ranging signal can still be transmitted in the precise ranging channel set by the OLT, thereby ensuring that the ranging does not affect the service transmission of other nodes.
Optionally, the ONU may continuously send the accurate ranging information until receiving the time difference t2 between the accurate ONU uplink frame header and the system uplink frame header sent by the OLT and the equalization delay value, or receiving a command to stop ranging sent by the OLT.
Step 6, after receiving the accurate ranging information returned by the ONU, the OLT calculates the time difference t2 and the balanced delay value of the uplink frame header of the ONU and the uplink frame header of the system accurately and sends the values to the ONU;
specifically, the OLT compares the upstream frame header of the system according to the phase of the received precise ranging signal, and then calculates the corresponding t2 value.
The OLT may calculate the equalization delay value in any of the following forms:
(1) the OLT records the sending time of the message and the time of receiving the response information (namely, the accurate ranging information) so as to calculate the corresponding equilibrium time delay;
(2) for example, a Super frame Counter in an identifier field in a GPON downlink frame may be used as a cycle Counter in the downlink frame, the uplink response information (i.e., the accurate ranging information) only needs to continuously send back the received count value, and after receiving the returned count value, the OLT compares the count value with a local Counter of the OLT to obtain a corresponding delay value, thereby calculating the equalization delay.
Step 7, the ONU receives the t2 value and the equalization delay value, realizes corresponding accurate ranging, namely, the ONU can adjust the upstream frame header according to the t2 value to form the upstream frame header in a normal working state; and corresponding equalization delay values can be used under the conditions of ONU sending burst, bandwidth adjustment and the like, so that synchronization of a plurality of ONUs and the start of a system uplink frame header are ensured, and collision is avoided.
It should be noted that, on the OLT, if the whole system is powered on again, that is, all ONUs need to initialize and measure distance, the OLT may determine a system uplink frame header according to the distance measurement signal sent by the ONU that is received first, and at this time, the system uplink frame header may directly select an uplink frame header corresponding to the distance measurement signal sent by the ONU that is received first.
The realization of the embodiment of the invention ensures that the ranging process of the slave node does not influence the normal service transmission of other slave nodes, namely the service transmission process of other slave nodes does not need to be suspended or interrupted, thereby ensuring the QoS (quality of service) of the service transmission. Moreover, the ranging scheme provided by the embodiment of the present invention does not need to suspend or interrupt other normal transmission services, so that a smoothing process is not needed on the master node side, and thus the ranging scheme provided by the embodiment of the present invention can eliminate the limitation of the logical distance difference between the master node and the slave node, so that the transmission distance of the system is longer, and the coverage area is larger. In addition, a low-speed transmitter and a low-speed receiver are adopted in the ranging process, so that the implementation cost of the ranging process is effectively reduced.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.
An embodiment of the present invention further provides a ranging apparatus in a communication network, where the apparatus is disposed in a slave node initiating a ranging operation, and a specific implementation structure of the ranging apparatus is shown in fig. 5, where the ranging apparatus may include:
a coarse ranging signal sending unit 501, configured to send a coarse ranging signal lower than the service rate to the master node, and request the master node to return a coarse ranging response signal to the slave node; the power of the coarse ranging signal sent by the coarse ranging signal sending unit 501 may be lower than the power of the service sent by the node (slave node), and specifically, the sending power of the corresponding coarse ranging signal may be determined according to the received power of the service signal sent by the master node;
the corresponding coarse ranging signal transmitting unit 501 may be a coarse ranging signal transmitter configured to transmit a coarse ranging signal, which is not used for transmitting a service; or, the coarse ranging signal sending unit may also be a service transmitter for sending a service; optionally, the corresponding coarse ranging signal transmitter and the service transmitter may use different wavelengths for transmitting signals, so that the receiving side separately obtains the corresponding coarse ranging signal; further, the coarse ranging signal sending unit 501 may also send the corresponding coarse ranging signal by using a random delay to avoid collision between the coarse ranging signals sent by different slave nodes, and certainly, if the number of slave nodes is small, the probability of collision is small, and the corresponding random delay may not be used in the course of sending the coarse ranging signal.
Moreover, the coarse ranging signal sending unit 501 may specifically send the coarse ranging signal at an initial uplink frame header position, where the initial uplink frame header position is determined according to a frame header position of a downlink frame sent by the master node to the slave node.
The rough ranging unit 502 is configured to obtain a rough ranging result in the rough ranging response signal after receiving the rough ranging response signal returned by the master node, so as to implement rough ranging.
Optionally, the ranging apparatus provided in the slave node may further include the following unit:
a precise ranging channel position determining unit 503, configured to determine a frame header position of the uplink frame according to the coarse ranging result in the received coarse ranging response signal after receiving the precise ranging start information sent by the master node, and determine a position of a precise ranging channel according to the frame header position;
an accurate ranging signal sending unit 504, configured to send an accurate ranging signal equal to the service rate through the accurate ranging channel determined by the accurate ranging channel position determining unit 503, where the accurate ranging signal carries accurate ranging information to request the master node to return an accurate ranging result; the process of the precise ranging signal sending unit sending the precise ranging signal equal to the traffic rate may specifically include: sending an accurate ranging signal with the length smaller than that of the accurate ranging channel at a selected position of the accurate ranging channel, wherein the corresponding selected position needs to ensure that the accurate ranging signal sent by the slave node does not exceed the range of the accurate ranging channel determined by the master node, and the rate and the power of the corresponding accurate ranging signal are the same as the rate and the power of a service to be sent;
and an accurate ranging unit 505, configured to receive an accurate ranging result sent by the master node, so as to implement accurate ranging, and complete an accurate ranging operation.
An embodiment of the present invention further provides a ranging apparatus in a communication network, where the apparatus is disposed in a master node, and is configured to cooperate with the slave node to implement a ranging process initiated by the slave node, and a specific implementation structure of the ranging apparatus is still shown in fig. 5, and may include:
a coarse ranging signal receiving unit 506 for receiving a coarse ranging signal lower than a traffic rate transmitted from a node; if the slave node transmits the coarse ranging signal using a wavelength different from the service signal, the coarse ranging signal receiving unit 506 may separate the corresponding coarse ranging signal using a wavelength filter; or, if the slave node uses the service transmitter to transmit the coarse ranging signal, the coarse ranging signal receiving unit 506 may also use an electrical filter to separate the corresponding coarse ranging signal;
a coarse ranging result sending unit 507, configured to return a coarse ranging response signal to the slave node after the coarse ranging signal receiving unit 506 receives the coarse ranging signal, where the coarse ranging response signal includes a coarse ranging result.
In order to achieve accurate ranging, the apparatus provided in the master node may further include the following elements:
a precise ranging starting unit 508 for sending precise ranging starting information to the slave node through the precise ranging channel to instruct the slave node to return the precise ranging information;
a precise ranging result transmitting unit 509, configured to calculate a precise ranging result and return the result to the slave node after receiving the precise ranging information transmitted by the slave node.
Optionally, the apparatus provided in the master node may further include at least one of the following processing units:
a precise ranging channel configuration unit 510, configured to set a corresponding precise ranging channel and only allow a predetermined low-priority service to be transmitted in the precise ranging channel;
the precise ranging channel service management unit 511 is configured to stop transmitting the service in the precise ranging channel when there is a service to be transmitted in the precise ranging channel that needs to be currently applied.
An embodiment of the present invention further provides a ranging system in a communication network, which has a specific structure as shown in fig. 5, and includes a master node and a slave node, where the master node includes the ranging device in the latter communication network, and the slave node includes the ranging device in the former communication network.
In the system provided in the embodiment of the present invention, if the coarse ranging mode is used for ranging, the corresponding ONU side may use a low-speed transceiver with a separate wavelength to implement ranging, as shown in fig. 6, the ONU includes an independently-installed low-speed transmitter (i.e., low-speed Tx) for ranging, and the low-speed transmitter is started only during ranging. In cooperation with the method, an independently arranged low-speed receiver (namely, low-speed Rx) is also included at the OLT for ranging; correspondingly, the OLT also comprises a wavelength filter which is used for separating the ranging signal from the service signal so as to transmit the ranging signal to the low-speed receiving; the filter may particularly, but not exclusively, be a thin film filter separating traffic signals and ranging signals having different wavelengths.
In the course of rough ranging, the ONU may send the ranging signal for a relatively long period of time, and the low-speed transmitters and receivers used for ranging on the ONU and the OLT may use continuous mode devices to further reduce the implementation cost.
In the system provided in the embodiment of the present invention, a low-speed signal may also be superimposed on the ONU service transmitter, as shown in fig. 7, at the ONU, a transmitter is shared by the coarse ranging process and the service transmission, where a burst mode is used during the service transmission, and a continuous mode is used during the coarse ranging process to transmit the low-speed coarse ranging signal. Accordingly, a separate low speed receiver (i.e., low speed Rx) is included at the OLT for receiving the corresponding coarse ranging information, and the low speed receiver can operate in a continuous mode; and after receiving the optical signal, the OLT divides the optical signal into two parts through a splitter: a part of the signals are accessed to a service receiver (namely a Burst receiver, a Burst Rx), and the coarse ranging signals are low-speed signals, so that the normal receiving of the service signals is not influenced; the other part is connected into the low-speed Rx, and a corresponding electrical filter (PD connected to the filter is a light receiving tube for converting an optical signal into a current signal) is provided in the low-speed Rx for filtering out a high-speed traffic signal, so that a corresponding coarse ranging signal can be correctly received.
In order to reduce the influence of the coarse ranging signal on normal service transmission as much as possible and ensure normal reception of the coarse ranging signal, the ONU needs to control the power of the coarse ranging signal reaching the OLT. In the embodiment of the invention, the corresponding rough ranging signal can be a low-frequency signal firstly, so that the receiving sensitivity of the low-speed Rx can be lower, and the power adjustment range of the rough ranging signal is increased. And initially setting, the ONU may set the initial coarse ranging signal transmission optical power with reference to the optical power value received by the downlink signal. For example, the master node may broadcast its transmit power information or master node transmitter type via a downlink signal. The slave node can estimate the actual uplink line loss according to the obtained master node transmission power information or transmitter type information and the measured actual received downlink signal power. Accordingly, an appropriate service signal transmitting optical power value (according to the receiving sensitivity of the OLT receiver) can be calculated, the receiving power of the OLT can be further reduced due to the low coarse ranging signal rate, and the ONU can reduce a value (for example, a difference between the selected service signal and the coarse transmitting signal receiving sensitivity) on the basis of the appropriate service signal transmitting power to transmit. The slave node may also calculate, according to the estimated loss value, a required coarse ranging signal transmission power to ensure that the coarse ranging signal power received by the master node is above the sensitivity. The slave node can select the two ways to calculate the coarse ranging signal transmission power according to the specific network application. By doing so, the slave node can transmit the rough ranging signal with a proper power, thereby avoiding the influence on the normal service signal; and the problem that the low master node cannot receive the signal is also avoided, unnecessary coarse ranging signal sending power adjustment processes can be reduced, and the ranging time is shortened. Meanwhile, the ONU can delay a random time and then carry out rough ranging, so that the probability that a plurality of ONUs carry out rough ranging at the same time can be reduced, and the influence of the rough ranging of the network on normal service signal transmission is further reduced.
In the system provided in the embodiment of the present invention, because the frequency of the normally transmitted service data is high, the transmitter module may use CDR (clock and data recovery) to filter the noise of the routing, but the CDR cannot normally operate when the frequency of the input signal is low, and because the coarse ranging signal is a low frequency signal, if the coarse ranging signal cannot be normally transmitted through the CDR path, the transmitter may need to bypass the CDR in the transmitter module when transmitting the coarse ranging signal. Specifically, as is readily apparent from comparison with the structure of the transmitter in the prior art shown in fig. 8A, the structure of the ONU according to the embodiment of the present invention may be as shown in fig. 8B, where the power adjustment and the CDR bypass link are mainly added at the ONU, and specifically, the bias current control module may be controlled by the control module in fig. 8B to perform the power adjustment. The driving module modulates the signal to the light emitting module, the light emitting module completes electro-optical conversion and converts an electric signal into an optical signal, and the bias current control module provides bias current of the light emitting module. In the working process: the ONU firstly transmits a rough ranging signal for a relatively long time, and stops transmitting when receiving a corresponding t1 value and an ONU ID or receiving an OLT ranging request suppression command; when a repeat transmission command is received (possibly containing a demand for power up or power down), the transmission is continued once more according to the new power; if no response is received within a certain time, the power is increased and then the rough ranging signal is sent. This is repeated until the t1 value and the ONU ID are received and the ranging request command is received simultaneously with the t1 value and the ONU ID, and the subsequent ranging process may be continued without processing the ranging request command.
Through the implementation of the embodiment of the invention, the corresponding ranging process can not affect the normal service transmission process of other nodes any more. Meanwhile, the limitation on the logical distance between the slave node and the master node can be eliminated, so that the network coverage is expanded.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (18)
1. A method for ranging in a communication network, comprising:
sending a rough ranging signal with a rate lower than the service rate to the main node at an initial uplink reference position, and requesting the main node to return a rough ranging response signal, wherein the initial uplink reference position is a position selected from downlink signals sent by the main node according to a preset rule;
and receiving the rough ranging response signal returned by the main node, and obtaining a rough ranging result according to the rough ranging response signal.
2. The method of claim 1, wherein:
the slave node is provided with a rough ranging signal transmitter and transmits the rough ranging signal through the rough ranging signal transmitter, and the rough ranging signal transmitter is not used for transmitting service;
or,
and the slave node adopts a service transmitter for transmitting service to transmit the rough ranging signal.
3. The method of claim 2, further comprising:
the rough ranging signal transmitter and the service transmitter adopt different wavelengths to transmit signals;
and/or the presence of a gas in the gas,
the sending power used by the slave node for sending the rough ranging signal is lower than the sending power used for sending the service; the slave node determines the transmission power of the rough ranging signal according to the received power of the downlink signal transmitted by the master node;
and/or the presence of a gas in the gas,
when the slave node transmits the coarse ranging signal, the slave node transmits the coarse ranging signal with a random delay.
4. A method according to any one of claims 1 to 3, characterized in that the method further comprises:
determining a reference position of an uplink signal according to a coarse ranging result in the received coarse ranging response signal, and determining the position of a precise ranging channel according to the reference position;
sending an accurate ranging signal equal to the service rate through the accurate ranging channel to request the master node to return an accurate ranging result to the slave node;
and the slave node receives the accurate ranging result sent by the master node.
5. The method of claim 4, wherein the step of transmitting the precise ranging signal equal to the traffic rate comprises:
and sending an accurate ranging signal with the length smaller than that of the accurate ranging channel at a selected position in the accurate ranging channel, wherein the selected position needs to ensure that the accurate ranging signal sent by the slave node does not exceed the range of the accurate ranging channel determined by the master node, and the rate and the power of the accurate ranging signal are the same as those of the sending service.
6. A ranging apparatus in a communication network, comprising:
a rough ranging signal sending unit, configured to send a rough ranging signal with a rate lower than a service rate to a master node at an initial uplink signal reference position, and request the master node to return a rough ranging response signal to a slave node, where the initial uplink signal reference position is a position selected from downlink signals sent from the master node to the slave node according to a predetermined rule;
and the rough ranging unit is used for receiving a rough ranging response signal returned by the main node, obtaining a rough ranging result according to the rough ranging response signal and realizing rough ranging.
7. The apparatus of claim 6, wherein the coarse ranging signal sending unit is a coarse ranging signal transmitter configured to send a coarse ranging signal, and wherein the coarse ranging signal transmitter is not used for sending traffic; or, the coarse ranging signal sending unit is a service transmitter for sending a service.
8. The device of claim 7, wherein, in the device,
the rough ranging signal transmitter and the service transmitter adopt different wavelengths to transmit signals;
and/or the presence of a gas in the gas,
the coarse ranging signal transmitting unit transmits the coarse ranging signal by using a random delay.
9. The apparatus of claim 7, wherein when the coarse ranging signal sending unit performs coarse ranging with the service transmitter, the coarse ranging signal bypasses a clock and data recovery module in the service transmitter and reduces transmission power of the service transmitter.
10. The apparatus of any one of claims 6 to 9, further comprising:
the accurate ranging channel position determining unit is used for determining the reference position of the uplink signal according to the coarse ranging result in the received coarse ranging response signal and determining the position of the accurate ranging channel according to the reference position;
the accurate ranging signal sending unit is used for sending an accurate ranging signal equal to the service rate through the accurate ranging channel determined by the accurate ranging channel position determining unit, wherein the accurate ranging signal carries accurate ranging information so as to request the main node to return an accurate ranging result;
and the accurate ranging unit is used for receiving an accurate ranging result sent by the main node and realizing accurate ranging.
11. The apparatus of claim 10, wherein the procedure of the precise ranging signal sending unit sending the precise ranging signal equal to the traffic rate specifically comprises:
and sending an accurate ranging signal with the length smaller than that of the accurate ranging channel at a selected position in the accurate ranging channel, wherein the selected position needs to ensure that the accurate ranging signal sent by the slave node does not exceed the range of the accurate ranging channel determined by the master node, and the rate and the power of the accurate ranging signal are the same as those of the sending service.
12. A method for ranging in a communication network, comprising:
receiving a coarse ranging signal transmitted from a node at a rate lower than a traffic rate;
and returning a rough ranging response signal to the slave node, wherein the rough ranging response signal comprises a rough ranging result.
13. The method of claim 12, further comprising:
the master node sends accurate ranging starting information to the slave node through the accurate ranging channel so as to indicate the slave node to return the accurate ranging information;
and after receiving the accurate ranging information sent by the slave node, the master node calculates an accurate ranging result and returns the accurate ranging result to the slave node.
14. The method of claim 13, further comprising:
the main node sets an accurate ranging channel for transmitting an accurate ranging signal and only allows the transmission of a preset low-priority service in the accurate ranging channel;
and if the service to be transmitted exists in the accurate ranging channel which needs to be applied currently, the master node controls the slave node to stop transmitting the service in the accurate ranging channel.
15. A ranging apparatus in a communication network, comprising:
a coarse ranging signal receiving unit for receiving a coarse ranging signal transmitted from a node at a rate lower than a traffic rate;
a coarse ranging result sending unit, configured to return a coarse ranging response signal to the slave node after the coarse ranging signal receiving unit receives the coarse ranging signal, where the coarse ranging response signal includes a coarse ranging result.
16. The apparatus of claim 15, wherein the coarse ranging signal receiving unit separates the coarse ranging signal using a wavelength filter; or, the coarse ranging signal receiving unit separates the coarse ranging signal by using an electrical filter.
17. The apparatus of claim 15 or 16, further comprising:
the accurate ranging starting unit is used for sending accurate ranging starting information to the slave node through the accurate ranging channel so as to indicate the slave node to return the accurate ranging information;
and the accurate ranging result sending unit is used for calculating an accurate ranging result and returning the accurate ranging result to the slave node after receiving the accurate ranging information sent by the slave node.
18. The apparatus of claim 17, further comprising at least one of the following processing units:
the accurate ranging channel configuration unit is used for setting the accurate ranging channel and only allowing the preset low-priority service to be transmitted in the accurate ranging channel;
and the accurate ranging channel service management unit is used for controlling the slave node to stop transmitting the service in the accurate ranging channel when the service to be transmitted exists in the accurate ranging channel which needs to be applied currently.
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| CN102142898B (en) * | 2011-03-29 | 2014-07-16 | 华为技术有限公司 | Ranging method and device of nested PON (passive optical network) |
| CN104284351B (en) * | 2013-07-04 | 2018-02-09 | 中国人民解放军信息工程大学 | A kind of distance-finding method and device |
| EP3117233B1 (en) | 2014-03-12 | 2023-06-21 | Telefonaktiebolaget LM Ericsson (publ) | Location of terminals in a communications network |
| CN107241138B (en) * | 2016-03-28 | 2021-06-08 | 中兴通讯股份有限公司 | XG-PON system and re-ranging control method for channel switching thereof |
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