CN111525997B - Wireless broadband ad hoc network transmission method - Google Patents

Abstract

The invention discloses a transmission method of a wireless broadband ad hoc network, which provides a transmission scheme of the wireless broadband ad hoc network, and solves the problem of transmission interruption during remote communication by adjusting a physical time-frequency resource distribution mode and a service mode aiming at the conditions that the transmission distance between a transmitting end and a receiving end of the wireless broadband ad hoc network is gradually increased and the channel condition is gradually deteriorated under a mobile environment; the scheme of the invention increases the coverage of the sending node by changing the physical resource allocation mode and reduces the network deployment cost. Meanwhile, under the mobile environment, with the increase of the transmission distance, the uninterrupted service is realized by orderly reducing the service mode.

Description

A wireless broadband ad hoc network transmission method

technical field

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

Background technique

Wireless ad hoc network is a new type of wireless network architecture that is completely different from traditional wireless cellular networks. The nodes in the network are all peers, and each node can send and receive signals. Compared with the traditional cellular network, the wireless ad hoc network has 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 existing wireless communication protocols, such as LTE protocol, WiFi protocol, and the like.

For wireless broadband ad hoc networks based on TD-LTE technology, the frame structure is generally shown in Figure 1. In the time domain, a radio frame includes ten subframes, each subframe includes two time slots, each time slot has a length of 0.5 ms, and each time slot includes 7 OFDM symbols. In the frequency domain, the system operating bandwidth is usually 5MHz/ 10MHz/20MHz, and can also be customized according to requirements. The working bandwidth is usually divided into a plurality of continuous sub-carriers 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), and the number of PRBs in the frequency domain is related to the working bandwidth.

As shown in FIG. 3 , all frequency domain resources on the first three OFDM symbols in a subframe are used to bear control information, and frequency domain resources on the remaining OFDM symbols are used to bear data blocks. A PRB in the frequency domain is the smallest resource allocation unit. A data block occupies one or more PRBs in the frequency domain, and multiple data blocks share PRBs within the working bandwidth. The control information corresponding to multiple data blocks shares the 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 demodulates the corresponding data block according to the control information.

In wireless broadband ad hoc networks, adaptive modulation and coding (Adaptive Modulation and Coding, AMC) technology is usually used. The receiving end estimates the wireless channel condition between the sending end and the receiving end according to the previous transmission, and usually uses Channel Quality Indication (CQI) for measurement. The receiving end feeds back the CQI information to the sending end. The CQI is usually divided into 0~15 levels, and each level corresponds to a different modulation and coding method, as shown in Figure 4. When the sender performs the next transmission, it selects the corresponding modulation and coding method according to the CQI level, and at the same time selects the data block size according to the CQI level and the number of allocated PRBs.

For different services, the higher the transmission rate requirement, the larger the data block transmitted each time. In the case of fixed wireless channel conditions, the received signal level can be improved by increasing the transmission power, or the transmission code rate can be reduced by increasing PRB resource allocation. Considering that one sending end needs to transmit data to multiple receiving ends, the PRB resource allocated to the data block corresponding to each receiving end is also limited. For mobile scenarios, the transmission distance between the sending end and the receiving end of the wireless ad hoc network may gradually increase, and the wireless channel conditions may gradually deteriorate. The transmission performance of long-distance communication cannot be guaranteed by using existing technologies.

Contents 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 condition gradually deteriorates In such a situation, by adjusting the physical time-frequency resource allocation method and business model, the problem of transmission interruption during long-distance communication can be solved.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

The present invention provides a wireless broadband ad hoc network transmission method, (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 the same 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 resource required for the next transmission according to the feedback CQI, and notifies other nodes of the time-frequency resource by broadcast in sending subframe #n The physical time-frequency resource;

(3): The sending node starts from subframe #n+K, and 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, within m consecutive subframes starting from subframe #n+K, their transmission does not occupy the P PRB resources;

(5): If the physical time-frequency resources of 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 resource 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 resources to make the code rate of the sent data block meet the demodulation requirements of the receiving node, 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 situation of the forward wireless channel, 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 it is not the first communication between the receiving node and the sending node, 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 sending node only transmits data to the receiving node in the sending subframe, the sending node adopts the existing physical resource allocation method, and adopts the Modulation and encoding 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 block sent by the sending node are mapped to the first x on physical resources on OFDM symbols.

Preferably, in (5),

If the physical time-frequency resources of multiple sending nodes are completely overlapped, the data blocks with high service priority will use the physical time-frequency resources preferentially; if the service priorities are the same, the HARQ retransmission data blocks will preferentially use the physical time-frequency resources ; If they are all newly transmitted or retransmitted data blocks, the sending node with the highest channel quality on the physical resource will use the physical time-frequency resource first; for the sending node that fails to compete for the physical time-frequency resource, Then re-broadcast the physical time-frequency resource information in a subframe after subframe #n, and compete for resources again;

If the frequency domain resources of the physical time-frequency resources generated by multiple sending nodes are completely or partially overlapped, and the value of K is different, the sending node with the smallest value of K will preferentially use the physical time-frequency resource; if the value of K is the same, then the Sending nodes with high channel quality on overlapping PRB resources use the physical time-frequency resources; sending nodes that have not obtained the physical time-frequency resources postpone sending, or do not occupy overlapping PRB resources for sending, or use multiple sending nodes When the physical time-frequency resources that occur completely overlap, re-compete for resources.

The beneficial effects of the present invention are:

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

(2) In the mobile environment, the service of the sending node changes with the transmission distance. With the increase of the transmission distance, the service mode is reduced orderly to realize the uninterrupted service.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the 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. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

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

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

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

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

FIG. 5 is a schematic diagram of a timing sequence for sending a data block by a sending node in the present invention;

FIG. 6 shows the resource allocation of multiple sending nodes in consecutive m subframes in the present invention;

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

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

Fig. 9 is a flowchart of the solution of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example

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

(1): The sending node of the wireless ad hoc network 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 allocated for one transmission Resources usually include several PRBs in a subframe, and one transmission will not occupy multiple consecutive subframes at the same time, that is, transmission is performed on P PRB resources in the allocated subframe #k. In the following prior art The physical resource allocation method is the same), and the modulation and coding method corresponding to the CQI level that does not exceed the second preset CQI threshold is used for transmission;

2) If it is not the first communication between the receiving node and the sending node, the receiving node estimates the CQI according to the last transmission, and feeds back the estimated CQI to the sending node; CQI estimation and feedback are existing technologies, and the performance of CQI estimation depends on the algorithm , this solution assumes that the receiving end can perform CQI error-free 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 condition has changed, and the CQI estimated and fed back based on the previous transmission can no longer be used as a reference for the next transmission, and the sending node uses physical resources in the prior art Allocation method, and use the modulation and coding method 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 adopts The modulation and coding mode corresponding to the CQI level is fed back for transmission.

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

Assuming that in the case of a fixed service, the size of the data packet sent each time is fixed, and when the data block is transmitted in the modulation and coding mode corresponding to the first preset CQI threshold, the number of PRBs required in a subframe is fixed (called is the number of reference PRBs); if the feedback CQI is lower than the first preset CQI threshold, and a maximum resource of the number of reference PRBs is allocated in one 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 resource allocation in the time domain can be increased, and the transmission power of the data block can be increased while ensuring the number of physical time-frequency resources;

For wireless broadband ad hoc networks with central nodes, the physical time-frequency resources corresponding to data blocks of sending nodes can be allocated by the central node; for wireless broadband ad hoc networks without central nodes, sending nodes can allocate physical time-frequency resources corresponding to data blocks by themselves. 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 PRB number, the time domain resources include at least one subframe and at most M subframes, and the value of M is limited in step (3);

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

(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 subframe and the start subframe of the sending data block; m≤M, is the number of subframes contained in the physical time-frequency resource determined by the sending node, and 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 resource;

After broadcasting the time-frequency of physical resources, the sending node starts data block transmission after K subframes to ensure that the broadcast message can be transmitted to other nodes in the network through multi-hop. The value of K is related to the network scale, node data, and inter-node It is related to factors such as distance. 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 the number of PRBs included in the physical time-frequency resource 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 on the first x OFDM symbols cannot be used For carrying control information; for the receiving node, it has been deduced through broadcast messages that the PRBs on the first x OFDM symbols of the m-1 subframes cannot carry control information, and then do not blindly detect control information on these physical resources, As shown in Figure 6;

For the sending data block of the sending node, its processing steps such as coding, scrambling, modulation, mapping, etc. are the same as those in the prior art; when performing physical resource mapping, it is mapped to the on the P PRB resources of the m subframes.

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

For the other sending node, its physical resource allocation method and resource mapping method are the same as 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 of 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 notifies other nodes of the physical time-frequency resource by broadcasting 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 physical time-frequency resources may partially or completely overlap, the physical time-frequency resources include time domain and frequency domain, the following 1 means that both the time domain and the frequency domain overlap, the following The above 2 refers to complete overlap or partial overlap in the frequency domain, but not complete overlap in the time domain, just like two rectangles can completely overlap in width, but can be staggered in length;

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

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

For the sending node that has not obtained the physical time-frequency resource, the sending can be postponed, or the overlapping PRB resource can not be occupied for sending, or the resource can be re-competed as described in step (1).

(6): If the distance between 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 of consecutive subframes m required by the sending node exceeds the maximum number of subframes M of resource allocation to make the code rate of the sent data block 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 business. When the data block is reduced but the physical resource remains the same, the code rate of the data block decreases.

For further illustration, assume a wireless broadband ad hoc network containing N nodes, where 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 lower level CQI 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, a modulation and coding scheme corresponding to CQI level 0 or 1 is adopted. If node A and node H are not communicating for the first time, node H estimates the CQI of the wireless channel based on the previous transmission and feeds it back to node A. If the time interval between node A’s current transmission and the previous transmission exceeds a certain threshold, such as exceeding 100ms, the channel is considered 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 uses the existing technology The physical resource allocation method is used, and the modulation and coding method corresponding to the feedback CQI level is used for transmission.

Assuming that in the case of a fixed service, the size of the data packet sent each time is fixed, and when the data block is transmitted in the modulation and coding mode corresponding to the first preset CQI threshold, the number of PRBs required in a subframe is fixed. The number of PRBs can be used as a reference number of 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 allocated by resources, for example, M=4. For a wireless broadband ad hoc network with a central node, the physical time-frequency resources of node A are allocated by the central node. For wireless broadband ad hoc networks without central nodes, 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 through physical layer measurement.

Node A broadcasts the determined physical time-frequency resource to other nodes in the network in subframe #n, the purpose is to let other nodes in the network know that the physical time-frequency resource has been occupied, and avoid Open the above resources. However, for wireless ad hoc networks 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 situation occurs.

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

If the physical time-frequency resources of sending node B and node A are completely overlapped, the physical time-frequency resources can be competed according to the priorities of sending data blocks corresponding to node A and node B: the data blocks with high service priority use the physical time-frequency resources first frequency resources; 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 sending node with the highest channel quality on the physical resource will be given priority Use the physical time-frequency resource. For the sending node that fails to compete for the physical time-frequency resource, it re-broadcasts the physical time-frequency resource information in a certain subframe after subframe #n, and competes for resources again.

If the frequency-domain resources of the physical time-frequency resources of sending node B and node A are completely or partially overlapped, but the time-domain start subframes of the physical time-frequency resources are different, the sending node with the smallest starting subframe number will preferentially use the physical time-frequency resources. time-frequency resources. If the start subframes of the time domain are also the same, the sending node with high channel quality on the coincident PRB resource uses the physical time-frequency resource. Assuming that node A preferentially uses the physical time-frequency resources through competition, node B may postpone transmission, or transmit without occupying overlapping PRB resources, or re-compete for resources.

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 in which the sending node broadcasts physical time-frequency resources and the subframe in which the sending data block starts The subframe interval between , the value 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 described in 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 on physical resources on OFDM symbols. But for subframe #n+K+1 to subframe #n+K+m, the P PRBs mentioned in the first three OFDM symbols cannot be used to carry control information. For the receiving node, it has been deduced through broadcast messages that the PRBs on the first three OFDM symbols of the m-1 subframes cannot carry control information, and then do not blindly detect control information on these physical resources. For the data block sent by the sending node, its processing steps, such as encoding, scrambling, modulation, mapping, etc., are the same as those in the prior art. When performing physical resource mapping, it is mapped to the P PRB resources of the m subframes in a manner of frequency domain first and then time domain.

Suppose the receiving node H is in a mobile state, and the distance from node A is getting farther and farther away, and the quality of the wireless channel is getting worse and worse. If the video service is always being transmitted between node A and node H, the number m of consecutive subframes allocated by the video service data block increases with the transmission distance, and m=M when a certain distance is reached. If the distance between the two continues to increase after that, the allocated physical time-frequency resources can no longer make the transmission code rate meet the demodulation requirements of receiving node H, node A will reduce the service to data service, and the size of the data block for each transmission will also be 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.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (3)

1. A wireless broadband ad hoc network transmission method, comprising:

(1): the 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 mode and a modulation coding mode according to the feedback CQI and carries out forward transmission with the receiving node next time;

(2): if the feedback CQI is lower than a first preset CQI threshold, the sending node determines physical time-frequency resources required by next transmission according to the feedback CQI, and informs other nodes of the physical time-frequency resources in a broadcast mode in a sending subframe # n;

(3): the transmitting node performs data block transmission on P PRBs in the continuous m subframes from the subframe # n + K;

(4): for other sending nodes in the network with the received feedback CQI not lower than a first preset CQI threshold, the transmission of the other sending nodes does not occupy the P PRB resources in m continuous subframes starting from the subframe # n + K;

(5): if the physical time-frequency resources generated by a plurality of sending nodes partially or completely coincide, the sending nodes compete for the physical time-frequency resources according to the priority of the sent data blocks;

(6): if the distance between two sending nodes exceeds a preset distance threshold, the two sending nodes can simultaneously use the same physical time-frequency resource;

(7): if the number M of continuous subframes required by the sending node exceeds the maximum number M of subframes allocated by resources, the code rate of the sent data block can meet the demodulation requirement of the receiving node, and the sending node reduces the service into the service with smaller data blocks;

if the following conditions are met, the sending node adopts a physical resource allocation mode in the prior art, otherwise, the physical resource allocation modes from (2) to (7) are adopted:

if the receiving node and the sending node are in communication for the first time and the sending node cannot predict the forward wireless channel condition, the existing physical resource allocation mode is adopted, and a modulation coding mode corresponding to the CQI grade which does not exceed a second preset CQI threshold is adopted for transmission; the existing physical resource allocation method specifically includes: transmitting on the P PRB resources within the allocated subframe # k;

if the receiving node and the sending node are not in first communication, the receiving node carries out CQI estimation according to the last transmission and feeds back the estimated CQI to the sending node;

and if the feedback CQI is lower than a first preset CQI threshold and the sending node only transmits data to the receiving node in a sending subframe, the sending node adopts the existing physical resource allocation mode and adopts a modulation coding mode corresponding to the feedback CQI grade for transmission.

2. A wireless broadband ad hoc network transmission method according to claim 1, wherein 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 coding information and the physical time-frequency resource information corresponding to the data block sent by the sending node are mapped on the physical resources on the first x OFDM symbols.

3. A wireless broadband ad hoc network transmission method according to claim 1, wherein in (5),

if the physical time-frequency resources generated by the plurality of sending nodes are completely overlapped, the data block with high service priority preferentially uses the physical time-frequency resources; if the service priorities are the same, the HARQ retransmission data block preferentially uses the physical time-frequency resource; if the data blocks are newly transmitted or retransmitted, the transmitting node preferentially uses the physical time-frequency resource with the highest channel quality on the physical resource; for the sending node which can not compete to the physical time-frequency resource, rebroadcasting the physical time-frequency resource information in a subframe after the subframe # n, and carrying out resource competition again;

if the frequency domain resources of the physical time-frequency resources generated by the plurality of sending nodes are completely or partially overlapped and the K values are different, the sending node with the minimum K value preferentially uses the physical time-frequency resources; if the K value is the same, the transmitting node with high channel quality on the superposed PRB resource uses the physical time frequency resource; and delaying transmission of the transmitting nodes which do not acquire the physical time frequency resources, or transmitting the PRB resources which do not occupy the superposition, or re-competing resources according to the way when the physical time frequency resources generated by a plurality of transmitting nodes are completely superposed.

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