CN104052569A - Method and device for switching MCS - Google Patents

Abstract

The invention discloses an MCS switching method and a device. The method comprises steps that: whether switching of MCS for communication between a first communication node and a second communication node is needed is detected; if yes, switching is carried out through a direct connection channel between the first communication node and the second communication node. The method solves technical problems of relatively large time delay and relatively high error rate caused by MCS switching through a network management system in the prior art, and the technical effects of reducing MCS switching time delay and reducing the error rate are realized.

Description

Method and device for switching MCS

technical field

The present invention relates to the field of communication, in particular, to a method and device for switching a Modulation Coding Scheme (MCS for short).

Background technique

Microwave communication, optical fiber communication and satellite communication are called the three main means of modern communication transmission. Microwave communication generally adopts a point-to-point transmission mode, and is currently mainly used in 2G or 3G mobile bearer networks to provide voice and data service transmission for mobile operators, with large transmission capacity, stable long-distance transmission quality, low investment, and construction Short cycle, easy maintenance and other advantages. Figure 1 shows a typical network topology of microwave communication applied to a mobile bearer network. The point-to-point scenario can be used not only between base stations but also for backbone transmission between base stations and base station control stations or access gateways.

Usually, a microwave communication node is shown in Figure 2, and consists of two parts: a modulation and demodulation unit and a radio frequency transceiver unit. Wherein, the modem unit includes: a baseband interface and a modem unit, and is generally placed indoors, so it is also called an In-Door Unit (IDU for short). The RF transceiver unit mainly realizes the RF transceiver function, and is generally placed on the iron tower together with the antenna, so it is also called an Out-Door Unit (ODU for short).

With the development of mobile wireless network and Ethernet technology, microwave transmission has gradually developed from traditional Time Division Multiplexing (TDM) service transmission to today's mixed service transmission (for example: Time Division Multiplexing, E1, Ethernet, etc. A mode in which various types of data are mixed), and the transmission capacity is gradually increasing. Data from different interfaces are uniformly scheduled and encapsulated into data frames, then modulated by the modem unit, and sent out by the radio frequency unit. Because the transmission mode of microwave point-to-point wireless communication has high requirements on the environment, it is necessary to adjust the modulation mode and code rate according to the influence of the environment to adapt to the current channel conditions. When the communication environment is good, a higher modulation mode is generally used. The throughput is higher; otherwise, the modulation method is lower.

At present, when MCS switching is required, the processing method is shown in Figure 3. After the system is powered on, the transceivers of Node A and Node B both work in the default Modulation Coding Scheme (MCS for short) and code rate Down. As the environment changes, when the current modulation method and code rate cannot meet the requirements of the channel, the receivers of node A and node B will send requests to the local central processing unit (Central Processing Unit, referred to as CPU) to switch the MCS The command is notified to the CPU of the opposite end through the upper network management system, and the switching command is sent to the local external receiving unit and Modem (modulation and demodulation unit), as well as the external receiving unit and Modem of the source node, thus ensuring the system Switch the corresponding MCS at the position of the same frame data.

However, when the above method is used for processing, the following problems will mainly occur:

1) Send the switching request to the CPU, and then upload it to the upper-layer network management system, which will cause a large switching delay, and the general switching delay will roughly reach 10ms to 20ms;

2) It is difficult to ensure that the external receiving units and Modem of Node A and Node B perform corresponding MCS switching at the same frame data position, resulting in bit errors;

3) The coordination of external network management is required, and the code required for implementation is relatively large.

For the above problems, no effective solution has been proposed yet.

Contents of the invention

Embodiments of the present invention provide a method and device for switching MCS, so as to at least solve the technical problems of large delay and high bit error rate caused by switching MCS through a network management system in the prior art.

According to an aspect of an embodiment of the present invention, a method for switching MCS is provided, including: detecting whether the MCS used for communication between the first communication node and the second communication node needs to be switched; The switching is performed through a direct channel between the first communication node and the second communication node.

Preferably, performing the switch over the direct channel between the first communication node and the second communication includes: when the first communication node determines that the switch needs to be performed, the first communication node sends The second communication node sends an MCS request message, wherein the MCS request message is used to notify the second communication node to use a new MCS for communication on a predetermined frame.

Preferably, the MCS request message is carried in the MCS_type domain data frame.

Preferably, after the above-mentioned first communication node sends the above-mentioned MCS request message to the above-mentioned second communication node, the above-mentioned method further includes: the above-mentioned second communication node receives the above-mentioned MCS request message; the sending AMC control module of the above-mentioned second communication node is detecting After receiving the frame header indication signal sent by the external connection unit of the second communication node, the above-mentioned MCS request message is notified to the external connection unit of the second communication node, so as to notify the external connection unit of the second communication node that it is receiving When the M-1th frame after the above MCS request message is reached, the above new MCS is used for communication, where M is a positive integer.

Preferably, after the above-mentioned MCS request message is notified to the external connection unit of the above-mentioned second communication node, the above-mentioned method further includes: the modem unit of the above-mentioned second communication node and the external connection unit of the above-mentioned second communication node transmit When the second communication node receives the Mth frame after the MCS request message, it uses the new MCS to communicate.

Preferably, after the above-mentioned MCS request message is notified to the external undertaking unit of the above-mentioned second communication node, the above-mentioned method further includes: after the above-mentioned second communication node receives the above-mentioned MCS request message, the receiving AMC control module of the above-mentioned first communication node The above-mentioned MCS request message sent by the modem unit of the above-mentioned second communication node is received in the M-1th frame of the above-mentioned second communication node, and is used to notify the above-mentioned first communication node to use the above-mentioned new MCS for communication; the modulation and demodulation of the above-mentioned first communication node The demodulation module starts to use the above-mentioned new MCS to communicate when receiving the next frame after the above-mentioned MCS request message; the external undertaking unit of the above-mentioned first communication node receives the above-mentioned second communication node after receiving the above-mentioned MCS request message. When the frame header of the next frame indicates a signal, the above-mentioned new MCS is used for communication.

Preferably, detecting whether the MCS used for communication between the first communication node and the second communication node needs to be switched includes: when the mean square error MSE is greater than a first predetermined threshold and/or the block error rate BLER is greater than a second predetermined threshold In the case of the threshold value, it is determined that the handover needs to be performed between the first communication node and the second communication node.

Preferably, the above method is applied in a microwave communication system.

According to another aspect of the embodiments of the present invention, there is provided a device for switching MCS, located in a peer-to-peer communication node, including: an adaptive modulation and coding AMC engine module, used to detect the Whether the MCS needs to be handed over; the originating AMC control module is configured to perform the handover through a direct channel with the other second communication node if it is determined to be yes.

Preferably, the sending AMC control module is further configured to send an MCS request message to the receiving AMC control module of the other communication node when the determination is yes, wherein the MCS request message is used to notify the other communication node that the The new MCS is used for communication on the predetermined frame.

In the embodiment of the present invention, in a point-to-point peer-to-peer communication system, if it is detected that the MCS adopted between two peer-to-peer communication nodes cannot meet the needs of the current system, when a new MCS needs to be used for communication, the two The direct channel switching between two peer-to-peer communication nodes, instead of switching through a third-party network management system other than the two peer-to-peer communication nodes, solves the delay caused by MCS switching through the network management system in related technologies. The technical problems of large size and high bit error rate have achieved the technical effect of reducing the MCS switching delay and reducing the bit error rate.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

FIG. 1 is a schematic diagram of a microwave point-to-point transmission scenario according to related technologies;

2 is a schematic diagram of the composition of a microwave transmission system according to the related art;

Fig. 3 is a block diagram of microwave adaptive modulation and encoding processing according to the related art;

Fig. 4 is a kind of preferred flowchart of the method for switching MCS according to the embodiment of the present invention;

FIG. 5 is a schematic diagram of a modulation and coding frame structure of microwave adaptive modulation and coding according to an embodiment of the present invention;

FIG. 6 is a preferred structural block diagram of an apparatus for switching an MCS according to an embodiment of the present invention;

Fig. 7 is a preferred processing block diagram of microwave adaptive modulation and coding according to an embodiment of the present invention.

Detailed ways

Hereinafter, the present invention will be described in detail with reference to the drawings and examples. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

The embodiment of the present invention provides a preferred method for switching MCS, as shown in Figure 4, the method includes the following steps:

Step S402: detecting whether the MCS used for communication between the first communication node and the second communication node needs to be switched;

Step S404: If it is determined to be yes, perform the handover through a direct channel between the first communication node and the second communication node.

In the preferred embodiment described above, in a point-to-point peer-to-peer communication system, if it is detected that the MCS adopted between two peer-to-peer communication nodes cannot meet the needs of the current system, when it is necessary to use a new MCS for communication, through the two The direct channel switching between two peer-to-peer communication nodes, instead of switching through a third-party network management system other than the two peer-to-peer communication nodes, solves the delay caused by MCS switching through the network management system in related technologies. The technical problems of large size and high bit error rate have achieved the technical effect of reducing the MCS switching delay and reducing the bit error rate.

In the above step S402, whether MCS switching is required can be determined in the following manner, if the mean square error (Mean Square Error, referred to as MSE) is greater than the first predetermined threshold and/or the Block Error Ratio (Block Error Ratio, referred to as BLER) is greater than a second predetermined threshold, it may be determined that the handover needs to be performed between the first communication node and the second communication node. Preferably, the above-mentioned judgment may be performed by the first communication node or by the second communication node. Of course, whichever node makes the judgment will trigger the above-mentioned handover process. In practical applications, there may be multiple MCSs, and each current MCS should correspond to the two above-mentioned thresholds (thresholds can be configured by software). Preferably, in order to ensure that there is no uncoded handover, some margin can be left in the selection of the threshold, that is, the set threshold value is a threshold interval, and when it is greater than any value in this interval, the corresponding handover will be performed.

In the above step S404, in order to make the handover directly through the direct channel between the two communication nodes, the corresponding handover request message may be carried in the data frame transmitted between the two communication nodes. In a preferred embodiment, switching over the direct channel between the first communication node and the second communication includes: when the first communication node determines that the switching is necessary, the first communication node sends The second communication node sends an MCS request message (that is, the first communication node triggers a subsequent switching process), wherein the MCS request message is used to notify the second communication node to use a new MCS for communication on a predetermined frame. For example, the MCS request message can be carried in the MCS_type domain data frame as shown in Figure 5, preferably, a section in the data frame can be preset to carry the MCS request message, for example, the MCS request message can be carried in the MCS_type domain In the upper bits of the data frame.

In order to realize that the external receiving unit and the modem unit of the first communication node and the second communication node can switch to the new MCS for communication in the same frame, the synchronization between the two communication nodes can be realized in the following way: After a communication node sends the MCS request message to the second communication node, the second communication node receives the MCS request message; however, the MCS request message is not sent to the external receiving unit of the second communication node at once, but at the second After the sending AMC control module of the communication node detects the frame header indication signal (sync) sent by the external receiving unit of the second communication node, it notifies the external receiving unit of the second communication node of the MCS request message, and uses the MCS request message to send Informing the external connection unit of the second communication node to use the new MCS for communication at the Mth frame after the second communication node receives the MCS request message, where M is a positive integer. That is, both communication nodes configure the value M in advance, and then instruct the external bearer unit of the second communication node to switch to the new MCS for communication at the M-1th frame after receiving the request message. Preferably, M can be configured when the entire communication system is initialized and powered on. That is, the modem unit of the second communication node and the external connection unit of the second communication node simultaneously use the new MCS for communication at the Mth frame after receiving the MCS request message from the second communication node.

In a preferred embodiment, the modem unit of the second communication node sends an MCS request message to the receiving AMC control module of the first communication node on the M-1th frame after receiving the MCS request message for notification The first communication node uses a new MCS to communicate; the modem module of the first communication node starts to use a new MCS to communicate when receiving the next frame after the MCS request message; the external receiving unit of the first communication node When receiving the frame header indication signal of the next frame, the new MCS is used for communication.

Because the external receiving unit of the second communication node has already started sending the first frame when receiving the MCS request message (request mcs), therefore, the external receiving unit can only count from the header of the next frame, but the modem directly starts from The current frame starts counting at the same time, so the Mth frame counted by the modem is the previous frame of the Mth frame counted by the external receiving unit, so that the modem unit of the first communication node and the external frame of the first communication node The transition unit, the modem unit of the second communication node, and the external transition unit of the second communication node may perform MCS switching in the same frame.

In each of the foregoing preferred implementation manners, the foregoing method may be, but not limited to, applied to a microwave communication system.

In this embodiment, there is also provided a device for switching MCS, which is located in a peer-to-peer communication node. The device is used to implement the above embodiments and preferred implementation modes, and what has been described will not be repeated. As used below, the term "unit" or "module" may be a combination of software and/or hardware that realizes a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementations in hardware, or a combination of software and hardware are also possible and contemplated. Fig. 6 is a preferred structural block diagram of a device for switching MCS according to an embodiment of the present invention, as shown in Fig. 6 , including: an adaptive modulation and coding (Adaptive Modulation and Coding, referred to as AMC) engine module determination unit 602 and an originating AMC The structure of the control module 604 will be described below.

An adaptive AMC engine module 602, configured to detect whether the MCS used for communication with another communication node needs to be switched;

The originating AMC control module 604 is coupled to the adaptive modulation and coding engine module 602, and is configured to perform the handover through a direct channel with the other second communication node if it is determined to be yes.

In a preferred embodiment, the above-mentioned sending AMC control module 604 is further configured to send an MCS request message to the receiving AMC control module of the other communication node in the case of determining yes, wherein the MCS request message is used for The other communication node is notified to use the new MCS for communication on a predetermined frame.

The above-mentioned device for switching MCS is located in the first communication node, and the above-mentioned receiving end AMC control module is located in the second communication node, however, it is worth noting that the first communication node and the second communication node are peers The communication nodes, the first communication node and the second communication node all have an adaptive AMC engine module, a sending-end AMC control module and a receiving-end AMC control module.

The present invention will be further explained below with a specific preferred system switching structure of adaptive coding and modulation in a point-to-point wireless communication system, but it should be noted that this preferred embodiment is only for better description of the present invention, and It does not constitute an improper limitation of the present invention.

Through the following embodiments, the point-to-point peer-to-peer wireless communication system can respond to changes in the wireless channel in a timely manner in a real channel, and quickly adjust the Modulation Coding Scheme (MCS for short) without error to adapt to the current channel. The system switching structure of the adaptive coding and modulation can support the switching of the modulation mode and the coding mode, and the hardware implementation structure is relatively simple, only some corresponding judgment conditions need to be added, and the resource overhead is relatively small. The implementation process is described in detail below, as shown in Figure 7:

S1: The Adaptive Modulation and Coding (AMC) engine module of Node B (equivalent to the above-mentioned first communication node) according to the mean square error (Mean Square Error, MSE for short) and block error rate (Block Error Ratio, referred to as BLER) to judge the change of the current link (preferably, the judgment condition can be configured by software); when the value of MSE or BLER exceeds a predetermined threshold, it can be determined that switching is required To the corresponding MCS, each current MCS corresponds to two predetermined threshold values (threshold values can be configured by software). Preferably, in order to ensure that there is no uncoded handover, some margin can be left in the selection of the threshold, that is, the set threshold value is a threshold interval, and when it is greater than any value in this interval, the corresponding handover will be performed.

S2: The sending AMC control module of this node is notified by the AMC engine module of the B node to carry the corresponding MCS request message (request mcs message) in the next frame, preferably, the request mcs message can be inserted into the frame shown in Figure 5 Send in the high bit of the MCS_tpye field in the frame format;

S3: The sending AMC control module of node B sends the data frame carrying the corresponding request mcs message;

S4: After the receiving AMC control module of A node (equivalent to the above-mentioned second communication node) receives the request mcs message, the request mcs message is notified to the sending AMC control module of A node;

S5: When the sending AMC control module of node A detects the frame header indication signal (sync) sent by the external receiving unit of node A, it will notify the received request mcs to the external receiving unit of node A. For the external receiving unit of node A As far as the receiving unit is concerned, the request mcs indicates the MCS that should be adopted on the pre_notice number frame, and the number of pre-notified frames of the pre_notice number (equivalent to the above M) can be configured by software at the initial power-on;

S6: When it is detected that the request mcs at this time is different from the request mcs received last time, the counter is started, the external receiving unit switches to the new MCS when the pre_notice number frame is counted, and the modem is counted to the pre_notice number frame , the low bit of the MCS type (MCS_tpye) field in the frame format shown in Figure 5 carries the request mcs message and sends it to node B, because sync is the indication signal of the frame header, so the external receiving unit receives the request mcs The first frame has already been sent, so the external receiving unit can only start counting from the header of the next frame, and the modem starts counting at the same time, so the pre_notice number frame counted by the modem is the pre_notice number frame counted by the external receiving unit previous frame. The issuance of the above pre-notification frame ensures that the fast switching is reduced by a few frames in the implementation time compared with the traditional implementation method, which is equivalent to reducing the time of 4-8 milliseconds;

S7: After analyzing the request mcs message, the receiving AMC control module of node B notifies the external receiving unit of node B to switch to a new MCS in the next frame, and starts a new MCS when the external receiving unit receives the frame header signal MCS, so as to ensure the synchronous switching with the modem.

In the above steps S5 and S6, the MCS pre-notifies the sending end of the external receiving unit, and the two parties switch the corresponding MCS at the position of the frame specified by the pre_notice number, thereby ensuring that no error occurs during the switching process. If the pre_noticenumber is configured as 1, the sending AMC control module will immediately notify the received request mcs to the external receiving unit after detecting the frame header indication signal (sync) sent by the external receiving unit, so that the external receiving unit can quickly To complete the MCS switchover, the longest delay in the whole process is only 4ms. Since the channel change is a gradual process, a delay of 8ms can keep up with the channel change. In the above step S7, the MCS pre-notifies the receiving end of the external receiving unit to request the receiving end to receive the switched data at the fastest speed. Adopting such a switching method not only ensures error-free switching of the system and faster response to current channel changes, but also makes the switching delay relatively small, and the code required for hardware implementation is also small.

In the above preferred embodiment, the channel adjustment information fed back by node B is used for MCS adjustment of the unidirectional link from A to B. Because A and B are peer nodes, the same is true for the channel adjustment information fed back by node A. At the same time, each adjustment is made between the two without affecting each other.

In another embodiment, software is also provided, and the software is used to implement the technical solutions described in the above embodiments and preferred implementation manners.

In another embodiment, there is also provided a storage medium, in which the software is stored, the storage medium includes but not limited to: optical discs, floppy disks, hard disks, rewritable memories, and the like.

From the above description, it can be seen that the present invention achieves the following technical effects: in a point-to-point peer-to-peer communication system, if it is detected that the MCS adopted between two peer-to-peer communication nodes cannot meet the current system needs, When a new MCS needs to be used for communication, switching is performed through a direct connection channel between two peer communication nodes, instead of switching through a third-party network management system other than the two peer communication nodes, which solves the problem of passing The technical problems of large delay and high bit error rate caused by the MCS switching of the network management system have achieved the technical effect of reducing the delay of MCS switching and reducing the bit error rate.

Obviously, those skilled in the art should understand that each module or each step of the above-mentioned present invention can be realized by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed in a network formed by multiple computing devices Alternatively, they may be implemented in program code executable by a computing device so that they may be stored in a storage device to be executed by a computing device, and in some cases in an order different from that shown here The steps shown or described are carried out, or they are separately fabricated into individual integrated circuit modules, or multiple modules or steps among them are fabricated into a single integrated circuit module for implementation. As such, the present invention is not limited to any specific combination of hardware and software.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A method for switching modulation and coding mode MCS, characterized in that, comprising: Detecting whether the MCS used for communication between the first communication node and the second communication node needs to be switched; If it is determined to be yes, the handover is performed through a direct channel between the first communication node and the second communication node. 2. The method according to claim 1, wherein performing the switching through the direct channel between the first communication node and the second communication comprises: When the first communication node determines that the handover is required, the first communication node sends an MCS request message to the second communication node, where the MCS request message is used to notify the second The communication node uses the new MCS to communicate on the predetermined frame. 3. The method according to claim 2, wherein the MCS request message is carried in the MCS_type domain data frame. 4. The method according to claim 2, wherein, after the first communication node sends the MCS request message to the second communication node, the method further comprises: The second communication node receives the MCS request message; After the sending AMC control module of the second communication node detects the frame header indication signal sent by the external connection unit of the second communication node, it notifies the MCS request message to the external connection unit of the second communication node A unit, configured to notify the external connection unit of the second communication node to use the new MCS for communication at the M-1th frame after receiving the MCS request message, where M is a positive integer. 5. The method according to claim 4, characterized in that, after notifying the MCS request message to the external undertaking unit of the second communication node, the method further comprises: The modem unit of the second communication node and the external connection unit of the second communication node use the new MCS to communicate when receiving the Mth frame after the MCS request message from the second communication node . 6. The method according to claim 4, characterized in that, after notifying the MCS request message to the external undertaking unit of the second communication node, the method further comprises: The receiving AMC control module of the first communication node receives the M-1 frame sent by the modem unit of the second communication node on the M-1th frame after the second communication node receives the MCS request message The MCS request message is used to notify the first communication node to use the new MCS for communication; The modem module of the first communication node starts to use the new MCS for communication at the next frame after receiving the MCS request message; The external connection unit of the first communication node starts to use the new MCS for communication when receiving the frame header indication signal of the next frame after the second communication node receives the MCS request message. 7. The method according to any one of claims 1 to 6, wherein detecting whether the MCS used for communication between the first communication node and the second communication node needs to be switched comprises: When the mean square error MSE is greater than a first predetermined threshold and/or the block error rate BLER is greater than a second predetermined threshold, it is determined that the switching between the first communication node and the second communication node is required. 8. The method according to any one of claims 1 to 6, characterized in that it is applied in a microwave communication system. 9. A device for switching modulation and coding mode MCS, characterized in that it is located in a peer-to-peer communication node, including: An adaptive modulation and coding AMC engine module, which is used to detect whether the MCS used for communication with another communication node needs to be switched; The originating AMC control module is configured to perform the handover through a direct channel with the other second communication node if it is determined to be yes. 10. The device according to claim 9, wherein the sending-end AMC control module is further configured to send an MCS request message to the receiving-end AMC control module of the other communication node when it is determined to be yes, wherein , the MCS request message is used to notify the other communication node to use a new MCS for communication on a predetermined frame.