CN111525997A - A wireless broadband ad hoc network transmission method - Google Patents

Abstract

The invention discloses a wireless broadband ad hoc network transmission method, and the invention proposes a wireless broadband ad hoc network transmission scheme, aiming at the mobile environment, the transmission distance between the wireless broadband ad hoc network sending end and the receiving end gradually increases When the channel conditions are gradually deteriorating, the problem of transmission interruption during long-distance communication can be solved by adjusting the physical time-frequency resource allocation mode and business mode; the solution of the present invention increases the coverage of the sending node by changing the physical resource allocation mode, reducing the network deployment. cost. At the same time, in the mobile environment, with the increase of the transmission distance, the service is not interrupted by orderly reducing the service mode.

Description

A wireless broadband ad hoc network transmission method

technical field

The present invention relates to the technical field of wireless communication, in particular to a wireless broadband ad hoc network transmission method.

Background technique

The wireless ad hoc network is a new wireless network architecture completely different from the traditional wireless cellular network. The nodes in the network are all peer-to-peer, and each node can send and receive signals. Compared with traditional cellular networks, wireless ad hoc networks have the advantages of flexible and simple networking, high network reliability, and large coverage. With the mature application of OFDM-MIMO (Orthogonal Frequency Division Multiple Access and Multiple Input Multiple Output) technology and the rapid development of multimedia services, wireless broadband ad hoc networks emerge as needed. Since the wireless ad hoc network does not have a unified standard, the communication between network nodes usually adopts the existing wireless communication protocol, such as the LTE protocol, the WiFi protocol, and the like.

For the wireless broadband ad hoc network based on TD-LTE technology, the frame structure is usually shown in Figure 1. In the time domain, one radio frame includes ten subframes, each subframe includes two time slots, each time slot is 0.5 ms in length, and each time slot includes 7 OFDM symbols. In the frequency domain, the operating bandwidth of the system is usually 5MHz/10MHz/20MHz, which can also be customized according to requirements. The working bandwidth is usually divided into a plurality of consecutive subcarriers with an interval of 15 kHz, and the time-frequency resource units are divided as shown in FIG. 2 . A resource composed of 7 consecutive OFDM symbols in the time domain and 12 consecutive subcarriers in the frequency domain becomes a physical resource block (Physical Resource Block, PRB). The number of PRBs in the frequency domain is related to the working bandwidth.

As shown in FIG. 3 , all the frequency domain resources on the first three OFDM symbols in a subframe are used to carry control information, and the frequency domain resources on the remaining OFDM symbols are used to carry data blocks. A PRB in the frequency domain is the smallest resource allocation unit. One data block occupies one or more PRBs in the frequency domain, and multiple data blocks share the PRBs within the working bandwidth. Control information corresponding to multiple data blocks shares physical resources on the first three OFDM symbols, and the control information is used to carry resource allocation information, modulation and coding information, etc. of the corresponding data blocks. The receiving end usually blindly detects the control information first, and then demodulates the corresponding data block according to the control information.

In a wireless broadband ad hoc network, an Adaptive Modulation and Coding (Adaptive Modulation and Coding, AMC) technology is usually used. The receiving end estimates the wireless channel condition between the transmitting end and the receiving end according to the previous transmission, and usually uses a channel quality indicator (Channel Quality Indication, CQI) to measure. The receiving end feeds back the CQI information to the transmitting end. The CQI is usually divided into 0 to 15 levels, and each level corresponds to a different modulation and coding mode, as shown in Figure 4. When the transmitting end performs the next transmission, the corresponding modulation and coding mode is selected according to the CQI level, and the data block size is selected according to the CQI level and the number of allocated PRBs.

For different services, the higher the transmission rate requirement is, the larger the data block is for each transmission. When the wireless channel conditions are fixed, the received signal level can be improved by increasing the transmit power, or the transmission code rate can be decreased by increasing the PRB resource allocation. Considering that a sender needs to transmit data to multiple receivers, the PRB resources allocated to the data blocks corresponding to each receiver are also limited. In the mobile scenario, the transmission distance between the wireless ad hoc network sender and receiver may gradually increase, and the wireless channel conditions gradually deteriorate. The existing technology cannot guarantee the transmission performance during long-distance communication.

SUMMARY OF THE INVENTION

In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a wireless broadband ad hoc network transmission method, aiming at the mobile environment, the transmission distance between the wireless broadband ad hoc network sending end and the receiving end gradually increases, and the channel conditions gradually deteriorate. In this case, the problem of transmission interruption during long-distance communication can be solved by adjusting the physical time-frequency resource allocation method and business mode.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

The present invention provides a wireless broadband ad hoc network transmission method. (1): A wireless ad hoc network sending node receives a wireless channel CQI fed back by a corresponding receiving node, and the sending node selects a physical resource allocation method and a modulation and coding method according to the feedback CQI, and is consistent with the received CQI. The receiving node performs the next forward transmission;

(2): If the feedback CQI is lower than the first preset CQI threshold, the sending node determines the physical time-frequency resources required for the next transmission according to the feedback CQI, and broadcasts to other nodes in the sending subframe #n. the physical time-frequency resources;

(3): starting from subframe #n+K, the sending node performs data block transmission on P PRBs in consecutive m subframes;

(4): For other sending nodes in the network whose received feedback CQI is not lower than the first preset CQI threshold, in m consecutive subframes starting from subframe #n+K, their transmission does not occupy the P PRB resources;

(5): If the physical time-frequency resources generated by multiple sending nodes partially or completely overlap, the sending nodes compete for the physical time-frequency resources according to the priority of sending data blocks;

(6): If the distance between two sending nodes exceeds the preset distance threshold, the two can use the same physical time-frequency resources at the same time;

(7): If the number m of consecutive subframes required by the sending node exceeds the maximum number M of subframes allocated by the resource, the sending data block code rate can meet the demodulation requirements of the receiving node, then the sending node reduces the service to data blocks smaller business.

Preferably, in (1):

If it is the first communication between the receiving node and the sending node, and the sending node cannot predict the forward wireless channel condition, the existing physical resource allocation method is adopted, and the modulation and coding method corresponding to the CQI level that does not exceed the second preset CQI threshold is adopted. to transmit;

If the communication between the receiving node and the sending node is not the first time, the receiving node estimates the CQI according to the last transmission, and feeds back the estimated CQI to the sending node;

If the feedback CQI is lower than the first preset CQI threshold, and the transmitting node only transmits data to the receiving node in the transmission subframe, the transmitting node adopts the existing physical resource allocation method and adopts the corresponding CQI level of the feedback. Modulation and coding method for transmission.

Preferably, in (3):

In the subframe #n+K, the P PRBs on the first x OFDM symbols are used to carry control information, and the modulation and coding information and physical time-frequency resource information corresponding to the data blocks sent by the sending node are mapped on the first x OFDM symbols. On physical resources on OFDM symbols.

Preferably, in (5),

If the physical time-frequency resources generated by multiple sending nodes completely overlap, the data block with higher service priority will preferentially use the physical time-frequency resource; if the service priority is the same, the HARQ retransmission data block will preferentially use the physical time-frequency resource ; If both are newly transmitted or retransmitted data blocks, the physical time-frequency resource is preferentially used by the sending node with the highest channel quality on the physical resource; for the sending node that fails to compete for the physical time-frequency resource, Then, the physical time-frequency resource information is rebroadcast in a certain subframe after subframe #n, and resource competition is performed again;

If the frequency domain resources of the physical time-frequency resources generated by multiple sending nodes completely or partially overlap, and the value of K is different, the sending node with the smallest K value preferentially uses the physical time-frequency resource; if the value of K is the same, the Sending nodes with high channel quality on overlapping PRB resources use the physical time-frequency resources; for sending nodes that have not acquired the physical time-frequency resources, delay sending, or do not occupy the overlapping PRB resources for sending, or send according to multiple sending nodes Re-competition for resources occurs when the physical time-frequency resources are completely coincident.

The beneficial effects of the present invention are:

(1) The present invention increases the coverage of the sending node by changing the physical resource allocation mode, and reduces the cost of network deployment.

(2) In the mobile environment of the present invention, the service of the sending node changes with the transmission distance, and with the increase of the transmission distance, the service is not interrupted by orderly reducing the service mode.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

Fig. 1 is the frame structure of the wireless broadband ad hoc network based on TD-LTE technology in the prior art;

2 is a schematic diagram of physical time-frequency resource division in the prior art;

3 is a schematic diagram of division of a control channel and a data channel in a subframe in the prior art;

Fig. 4 is the modulation mode and code rate corresponding to CQI level in the prior art;

Fig. 5 is the time sequence diagram of sending the data block by the sending node of the present invention;

Fig. 6 is the resource allocation of multiple sending nodes in m consecutive subframes according to the present invention;

FIG. 7 is a schematic diagram of overlapping physical resources corresponding to two sending nodes according to the present invention;

Fig. 8 is the schematic diagram that the transmission service of the present invention changes according to the transmission distance;

Figure 9 is a flow chart of the solution of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example

The present invention provides a wireless broadband ad hoc network transmission method, comprising:

(1): The wireless ad hoc network sending node receives the wireless channel CQI fed back by the corresponding receiving node, and the sending node selects a physical resource allocation method and a modulation and coding method according to the feedback CQI, and performs the next forward transmission with the receiving node;

If the following conditions are met, the sending node adopts the physical resource allocation method in the prior art; otherwise, the physical resource allocation method from (2) to (7) is adopted:

1. If it is the first communication between the receiving node and the sending node, and the sending node cannot predict the situation of the forward wireless channel, the physical resource allocation method in the prior art is adopted (in the prior art, the physical time-frequency resource allocated for one transmission is Usually it includes several PRBs in one subframe, and one transmission will not occupy multiple consecutive subframes at the same time, that is, the transmission is performed on the P PRB resources in the allocated subframe #k, the following in the prior art The physical resource allocation method is also the same), and adopts the modulation and coding method corresponding to the CQI level that does not exceed the second preset CQI threshold for transmission;

20. If the communication between the receiving node and the sending node is not the first time, the receiving node performs CQI estimation according to the last transmission, and feeds back the estimated CQI to the sending node; CQI estimation and feedback are the prior art, and the CQI estimation performance depends on the algorithm , this scheme assumes that the receiving end can perform CQI indifference estimation and feedback. If the time interval between the next transmission and the last transmission exceeds a certain threshold, it can be considered that the channel conditions have changed, and the CQI estimated and fed back according to the last transmission cannot be used as a reference for the next transmission, and the sending node adopts the physical resources in the prior art. Allocation mode, and use the modulation and coding mode corresponding to the CQI level that does not exceed the second preset CQI threshold for transmission;

3. If the feedback CQI is lower than the first preset CQI threshold, and the sending node only transmits data to the receiving node in the sending subframe, the sending node adopts the physical resource allocation method in the prior art, and uses the feedback The modulation and coding mode corresponding to the CQI level is transmitted.

(2): If the feedback CQI is lower than the first preset CQI threshold, the sending node determines the physical time-frequency resources required for the next transmission according to the feedback CQI, and broadcasts to other nodes in the sending subframe #n. The physical time-frequency resources, as shown in Figure 5;

Assuming that the service is fixed, the size of the data packet sent each time is fixed, and the number of PRBs required in a subframe is fixed when the data block transmission is performed in the modulation and coding mode corresponding to the first preset CQI threshold (called is the number of reference PRBs); if the feedback CQI is lower than the first preset CQI threshold, and at most resources of the reference PRB number are allocated in a subframe, the transmission code rate of the data block is higher than the code rate corresponding to the feedback CQI level, resulting in The receiving node cannot demodulate correctly; therefore, when the number of PRBs in the frequency domain is limited, the amount of time-domain resource allocation can be increased, while ensuring the number of physical time-frequency resources, the transmission power of the data block is also improved;

For a wireless broadband ad hoc network with a central node, the physical time-frequency resources corresponding to the data blocks of the sending node can be allocated by the central node. For wireless broadband ad hoc networks without a central node, the sending node can allocate the physical time-frequency resources corresponding to the data blocks by itself. When allocating physical time-frequency resources, PRB resources with better transmission performance can be selected through physical layer measurement, and the number of PRBs is not less than the number of PRBs required to ensure channel estimation performance, and not higher than the reference PRBs number, the time domain resource includes at least one subframe and at most M subframes, and the value of M is limited in step (3);

The sending node sends the determined physical time-frequency resources to other nodes in the network by broadcasting. For a wireless broadband ad hoc network with a central node, the central node can perform resource scheduling on other nodes to avoid the physical time-frequency resources; for In a wireless broadband ad hoc network without a central node, after receiving the physical time-frequency resource information, other nodes avoid the physical time-frequency resource when transmitting data blocks.

(3): The sending node starts from subframe #n+K, and performs data block transmission on P PRBs in consecutive m subframes; where K>0, is the subframe in which the sending node broadcasts physical time-frequency resources The subframe interval between the start subframe of the sending data block; m≤M, is the number of subframes included in the physical time-frequency resource determined by the sending node, M is the maximum number of subframes allocated by the resource; P is the number of subframes determined by the sending node The number of PRBs included in the physical time-frequency resources;

After the sending node broadcasts the physical resource time and frequency, it starts to transmit data blocks after K subframes to ensure that the broadcast message can be transmitted to other nodes in the network through multi-hop mode. Factors such as distance are related. For a network with fewer nodes and a smaller coverage area, the value of K is also smaller; the parameters m and P are the number of subframes and PRBs included in the physical time-frequency resources determined by the sending node in step 2. , the minimum value of m is 1, and the maximum value does not exceed the maximum number of subframes M;

For subframe #n+K, the P PRBs on the first x OFDM symbols can be used to carry control information, and the modulation and coding information and physical time-frequency resource information corresponding to the data block sent by the sending node are mapped to the first x On physical resources on OFDM symbols, where 0<x≤3; but for subframe #n+K+1 to subframe #n+K+m, the P PRBs described in the first x OFDM symbols cannot be used For carrying control information; for the receiving node, it has been inferred through broadcast messages that the PRBs on the first x OFDM symbols of the m-1 subframes cannot carry control information, so the control information is not blindly detected on these physical resources, As shown in Figure 6;

For the data block sent by the sending node, the processing steps such as coding, scrambling, modulation, mapping, etc. are the same as those in the prior art; when mapping physical resources, map to the on the P PRB resources of m subframes.

(4): For other sending nodes in the network whose received feedback CQI is not lower than the first preset CQI threshold, in m consecutive subframes starting from subframe #n+K, their transmission does not occupy the P PRB resources;

For the other sending nodes, the physical resource allocation and resource mapping methods are the same as in the prior art; through the broadcast message of the sending node, the resource allocation in the m subframes avoids the P PRB resources, mutual interference is avoided.

(5): If the physical time-frequency resources generated by multiple sending nodes partially or completely overlap, the sending nodes compete for the physical time-frequency resources according to the priority of sending data blocks;

In (2), the sending node broadcasts the physical time-frequency resource to other nodes in subframe #n, but there may be one or more nodes in the network that have determined their own data before receiving the broadcast message The physical time-frequency resources used for transmission, the two kinds of physical time-frequency resources may overlap partially or completely. The physical time-frequency resources include the time domain and the frequency domain. The following ① means that both the time domain and the frequency domain overlap, and the following The above-mentioned ② refers to the complete or partial overlap in the frequency domain, but not in the time domain, just like two rectangles can be completely overlapped in width and staggered in length;

1. If the physical time-frequency resources broadcast by two or more sending nodes completely overlap (the time domain and frequency domain both overlap), the values of n, K and P corresponding to the two or more sending nodes must be completely The same, the physical time-frequency resources can be competed according to the priority of sending data blocks: the data blocks with high service priority use the physical time-frequency resources first; if the service priorities are the same, HARQ (Hybrid Automatic Repeat reQuest, hybrid automatic Retransmission request) The physical time-frequency resources are preferentially used for retransmission data blocks; if all are newly transmitted or retransmitted data blocks, the sending node with the highest channel quality on the physical resources preferentially uses the physical time-frequency resources . For the sending node that fails to compete for the physical time-frequency resource, rebroadcast the physical time-frequency resource information in a certain subframe after subframe #n, and perform resource competition again;

2. If the frequency domain resources of the physical time-frequency resources broadcast by two or more sending nodes completely overlap or partially overlap, but the time domain start subframes are different, that is, the value of K is different (when the subframes corresponding to multiple nodes #n When they are the same, but because the value of K is different, the value of n+K is also different, which corresponds to the complete or partial overlap in the frequency domain, but inconsistent in the time domain), then the sending node with the smallest K value preferentially uses the physical time-frequency resources. If the starting subframes in the time domain are also the same, that is, the value of K is the same, the sending node with high channel quality on the coincident PRB resource uses the physical time-frequency resource.

For a sending node that has not acquired the physical time-frequency resources, the sending may be delayed, or the overlapping PRB resources may not be occupied for sending, or the resources may be re-competed according to step (1).

(6): If the distance between the two sending nodes exceeds the preset distance threshold, it can be considered that the two will not interfere with each other, and the two can use the same physical time-frequency resources at the same time;

(7): For the sending node, if the number m of consecutive subframes required by the sending node exceeds the maximum number M of subframes allocated by the resource, the sending data block code rate can meet the demodulation requirements of the receiving node, then the sending node Reduce the business to a business with smaller data blocks;

For sending and receiving nodes with too long transmission distance and poor channel quality, even if the physical resource allocation method is adopted, the current service cannot be supported, and the service mode needs to be changed to reduce the size of the data block, for example, from video service to data service, or Reduced to voice services. When the data block is reduced but the physical resources remain unchanged, the data block code rate decreases.

For further illustration, assume a wireless broadband ad hoc network including N nodes, in which node A will send data blocks to node H for communication. If node A sends data blocks to node H for the first time, node A cannot predict the forward wireless channel. In this case, the physical resource allocation method in the prior art is used, and the modulation and coding method corresponding to the CQI of the lower level is used for transmission (that is, the modulation and coding method corresponding to the CQI level that does not exceed the second preset CQI threshold is used for transmission) , for example, the modulation and coding mode corresponding to CQI level 0 or 1 is adopted. If the communication between node A and node H is not the first time, node H estimates the CQI of the wireless channel according to the previous transmission and feeds it back to node A. If the time interval between the current transmission of node A and the previous transmission exceeds a certain threshold, such as more than 100ms, it is considered that the channel condition It has changed, and the feedback CQI can no longer be used as a reference for this transmission. Node A adopts the same transmission scheme as the first communication. In the case that the feedback CQI is still valid but lower than the preset first preset CQI threshold (for example, the threshold is CQI level 7), if node A only transmits data to node H in the sending subframe, node A adopts the prior art The physical resource allocation method is adopted, and the modulation and coding method corresponding to the feedback CQI level is used for transmission.

Assuming that in the case of fixed services, the size of the data packet sent each time is fixed, and the number of PRBs required in a subframe is fixed when the data block transmission is performed in the modulation and coding mode corresponding to the first preset CQI threshold, this The number of PRBs can be used as the number of reference PRBs. If the feedback CQI corresponds to the first preset CQI threshold but does not belong to the above situation, the physical time-frequency resources allocated by the node include P PRB resources on m consecutive subframes, and P is not less than the number of PRBs required to ensure channel estimation performance , not higher than the above reference PRB number. The minimum value of m is 1, and the maximum value is M, where M is the maximum number of subframes for resource allocation, for example, M=4. For a wireless broadband ad hoc network with a central node, the physical time-frequency resources of the above node A are allocated by the central node. For a wireless broadband ad hoc network without a central node, node A allocates physical time-frequency resources corresponding to data blocks by itself. When allocating physical time-frequency resources, PRB resources with better transmission performance can be selected by means of physical layer measurement.

Node A sends the determined physical time-frequency resource to other nodes in the network by broadcasting in subframe #n, the purpose is to let other nodes in the network know that the physical time-frequency resource is occupied, and avoid it when other nodes transmit. Open the above resources. However, for a wireless ad hoc network with a large number of hops, some nodes need to receive the broadcast message after two hops. Before receiving the broadcast message, these nodes have already determined the physical time-frequency resources used for their own data transmission, so they will A resource conflict occurs.

If the physical time-frequency resources of sending node B and node A overlap completely or partially, but node B and node A are distributed in opposite directions at the network edge, and the distance between them exceeds a preset distance threshold, such as 5 kilometers, you can It is considered that Node B and Node A will not interfere with each other by using the same physical time-frequency resources, and they can use the same physical time-frequency resources.

If the physical time-frequency resources of the sending node B and the node A completely overlap, the physical time-frequency resources can be competed according to the priorities of the sending data blocks corresponding to the node A and the node B: the data blocks with higher service priorities are given priority to use the physical time-frequency resources. If the service priorities are the same, the HARQ retransmission data blocks preferentially use the physical time-frequency resources; if they are all newly transmitted or retransmitted data blocks, the sending node has the highest channel quality on the physical resources. The physical time-frequency resources are used. For a sending node that fails to compete for the physical time-frequency resource, the physical time-frequency resource information is re-broadcast in a certain subframe after subframe #n, and resource competition is performed again.

If the frequency domain resources of the physical time-frequency resources of the sending node B and the node A are completely or partially coincident, but the time domain starting subframes of the physical time-frequency resources are different, the sending node with the smallest starting subframe number preferentially uses the physical time-frequency resources. time-frequency resources. If the time domain start subframe is also the same, the transmitting node with high channel quality on the overlapping PRB resource uses the physical time-frequency resource. Assuming that Node A preferentially uses the physical time-frequency resources in a competitive manner, Node B can delay sending, or send without occupying overlapping PRB resources, or compete for resources again.

Node A starts from subframe #n+K, and performs data block transmission on P PRBs in consecutive m subframes, where K>0 is the subframe where the sending node broadcasts physical time-frequency resources and the starting subframe for sending data blocks The value of the subframe interval is related to factors such as network scale, node data, and distance between nodes. For a network with fewer nodes and a smaller coverage area, the value of K is also smaller; m≤M is the sending node The number of subframes included in the determined physical time-frequency resource, M is the maximum number of subframes allocated by the resource; P is the number of PRBs included in the physical time-frequency resource determined by the sending node. For subframe #n+K, the P PRBs on the first three OFDM symbols can be used to carry control information, and the modulation and coding information and physical time-frequency resource information corresponding to the data block sent by the sending node are mapped in the first three OFDM symbols. physical resources on OFDM symbols. But for subframe #n+K+1 to subframe #n+K+m, the P PRBs described in the first three OFDM symbols cannot be used to carry control information. For the receiving node, it has been inferred through the broadcast message that the PRBs in the first three OFDM symbols of the m-1 subframes cannot carry control information, so the control information is not blindly detected on these physical resources. For the sending data block of the sending node, the processing steps such as coding, scrambling, modulation, and mapping are the same as those in the prior art. When performing physical resource mapping, the P PRB resources of the m subframes are mapped to the P PRB resources in the frequency domain first and then the time domain.

It is assumed that the receiving node H is in a mobile state, and the distance from the node A is getting farther and farther, and the wireless channel quality is getting worse and worse. If the video service is always transmitted between the node A and the node H, the number m of consecutive subframes allocated by the video service data block increases continuously with the transmission distance, and when a certain distance is reached, m=M. If the distance between the two continues to increase since then, the allocated physical time-frequency resources can no longer make the transmission code rate meet the demodulation requirements of the receiving node H, and the node A reduces the service to data service, and the size of the data block for each transmission is also reduced accordingly. Small. If the distance between the two is further increased, the service can be gradually reduced to voice service or short message service. Only when a certain limit is reached, the service between node A and node H is interrupted.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (4)

1. a wireless broadband ad hoc network transmission method, is characterized in that, comprises: (1): The wireless ad hoc network sending node receives the wireless channel CQI fed back by the corresponding receiving node, and the sending node selects a physical resource allocation method and a modulation and coding method according to the feedback CQI, and performs the next forward transmission with the receiving node; (2): If the feedback CQI is lower than the first preset CQI threshold, the sending node determines the physical time-frequency resources required for the next transmission according to the feedback CQI, and broadcasts to other nodes in the sending subframe #n. the physical time-frequency resources; (3): starting from subframe #n+K, the sending node performs data block transmission on P PRBs in consecutive m subframes; (4): For other sending nodes in the network whose received feedback CQI is not lower than the first preset CQI threshold, in m consecutive subframes starting from subframe #n+K, their transmission does not occupy the P PRB resources; (5): If the physical time-frequency resources generated by multiple sending nodes partially or completely overlap, the sending nodes compete for the physical time-frequency resources according to the priority of sending data blocks; (6): If the distance between two sending nodes exceeds the preset distance threshold, the two can use the same physical time-frequency resources at the same time; (7): If the number m of consecutive subframes required by the sending node exceeds the maximum number M of subframes allocated by the resource, the sending data block code rate can meet the demodulation requirements of the receiving node, then the sending node reduces the service to data blocks smaller business. 2. a kind of wireless broadband ad hoc network transmission method as claimed in claim 1 is characterized in that, in (1): If it is the first communication between the receiving node and the sending node, and the sending node cannot predict the forward wireless channel condition, the existing physical resource allocation method is adopted, and the modulation and coding method corresponding to the CQI level that does not exceed the second preset CQI threshold is adopted. to transmit; If the communication between the receiving node and the sending node is not the first time, the receiving node estimates the CQI according to the last transmission, and feeds back the estimated CQI to the sending node; If the feedback CQI is lower than the first preset CQI threshold, and the transmitting node only transmits data to the receiving node in the transmission subframe, the transmitting node adopts the existing physical resource allocation method and adopts the corresponding CQI level of the feedback. Modulation and coding method for transmission. 3. a kind of wireless broadband ad hoc network transmission method as claimed in claim 1 is characterized in that, in (3): In the subframe #n+K, the P PRBs on the first x OFDM symbols are used to carry control information, and the modulation and coding information and physical time-frequency resource information corresponding to the data blocks sent by the sending node are mapped on the first x OFDM symbols. On physical resources on OFDM symbols. 4. a kind of wireless broadband ad hoc network transmission method as claimed in claim 1 is characterized in that, in (5), If the physical time-frequency resources generated by multiple sending nodes completely overlap, the data block with higher service priority will preferentially use the physical time-frequency resource; if the service priority is the same, the HARQ retransmission data block will preferentially use the physical time-frequency resource ; If both are newly transmitted or retransmitted data blocks, the physical time-frequency resource is preferentially used by the sending node with the highest channel quality on the physical resource; for the sending node that fails to compete for the physical time-frequency resource, Then, the physical time-frequency resource information is rebroadcast in a certain subframe after subframe #n, and resource competition is performed again; If the frequency domain resources of the physical time-frequency resources generated by multiple sending nodes completely or partially overlap, and the value of K is different, the sending node with the smallest K value preferentially uses the physical time-frequency resource; if the value of K is the same, the Sending nodes with high channel quality on overlapping PRB resources use the physical time-frequency resources; for sending nodes that have not acquired the physical time-frequency resources, delay sending, or do not occupy the overlapping PRB resources for sending, or send according to multiple sending nodes Re-competition for resources occurs when the physical time-frequency resources are completely coincident.

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