CN111885612B - Working frequency band selection method for wireless ad hoc network during subnet splitting - Google Patents

Abstract

The invention discloses a working frequency band selection method when a wireless ad hoc network is split into subnets. A wireless ad hoc network is split into a first subnet and one or more second subnets, or is split into two or more a third subnet, wherein the ratio of the number of communication nodes between the first subnet and each of the second subnets is not lower than a preset ratio threshold of one, and the number of communication nodes of each of the second or third subnets The ratio of the number of communication nodes is not higher than the preset ratio threshold two; the first sub-network, the second sub-network and the third sub-network select their respective working frequency bands, and the communication nodes in the sub-network are on the selected working frequency band data transfer. Aiming at the wireless broadband ad hoc network, the invention solves the problem of working frequency band selection when an ad hoc network is split into a plurality of sub-networks, so that the split ad-hoc network sub-network can work normally, and at the same time, interference between networks is avoided.

Description

A method for selecting working frequency band when a wireless ad hoc network performs subnet splitting

technical field

The invention relates to the technical field of ad hoc networks, in particular to a method for selecting a working frequency band when a wireless ad hoc network performs sub-network splitting.

Background technique

A wireless ad hoc network is a new wireless network architecture completely different from the traditional wireless cellular network, and includes a temporary autonomous network with multiple communication nodes. The nodes in the network are all peer-to-peer, and each communication node is equipped with a wireless transceiver, which has the functions of sending, forwarding and receiving, so any two nodes in the network can communicate through a direct link or a multi-hop link. Compared with traditional cellular networks, wireless ad hoc networks do not need to rely on infrastructure, and have the advantages of flexible and simple networking, high network reliability, and large coverage.

With the rapid development of multimedia service requirements and the mature application of broadband communication technology represented by OFDM-MIMO (Orthogonal Frequency Division Multiple Access and Multiple Input Multiple Output) technology, wireless ad hoc networks based on broadband communication technology emerge in response to demand. . Due to the lack of unified technical specifications for wireless broadband ad hoc networks, some manufacturers usually use existing wireless broadband communication technologies to develop customized wireless ad hoc network nodes based on proprietary protocols by modifying or learning from the communication protocols of existing wireless broadband cellular networks. , such as WiFi protocol and 4G LTE protocol.

In some usage scenarios, such as in military battlefields, a large ad hoc network may be split into multiple subnets, each of which contains a part of the communication nodes from the original ad hoc network, as the network topology changes according to mission requirements. Before the subnet is split, all communication nodes form a network, and all data transmissions within the network use the same working frequency band. Since the time-frequency resources are allocated and scheduled uniformly, different concurrent transmissions do not interfere with each other. After the network is split, each subnet works independently. Due to the lack of resource coordination between networks, when different subnets use the same or part of the same working frequency band, different subnets may interfere with each other.

In addition, before the sub-network is split, a large ad hoc network contains more nodes and usually works on a working frequency band with a larger bandwidth. When a large ad hoc network is split into multiple subnets, the number of nodes contained in each subnet may be greatly reduced compared to the original ad hoc network, so the subnet can choose a working frequency band with a smaller bandwidth, or a part of the original working frequency band. In general, the bandwidth of the working frequency band is best matched with the number of communication nodes in the network, so as to avoid the transmission performance degradation or resource waste caused by insufficient resources.

At present, no working frequency band selection technology for subnet splitting has been found, especially for wireless broadband ad hoc networks.

SUMMARY OF THE INVENTION

In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a working frequency band selection method when a wireless ad hoc network is split into subnets, and for the wireless broadband ad hoc network, it solves the problem of working when an ad hoc network is split into multiple subnets. The problem of frequency band selection enables the divided ad hoc network subnet to work normally, while avoiding interference between networks.

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

The present invention provides a method for selecting a working frequency band when a wireless ad hoc network is split into subnets. A wireless ad hoc network is split into a first subnet and one or more second subnets, or is split into two or more The third sub-network, wherein the ratio of the number of communication nodes between the first sub-network and each of the second sub-networks is not lower than a preset ratio threshold of one, and the communication between the second sub-network or the third sub-network The ratio of the number of nodes is not higher than the preset ratio threshold two;

The first sub-network, the second sub-network and the third sub-network select respective working frequency bands, and the communication nodes in the sub-networks perform data transmission on the selected working frequency bands.

Preferably, the first subnet selects the same working frequency band as the wireless ad hoc network;

When the wireless ad hoc network supports single-band transmission, each of the second sub-network or the third sub-network selects a segment of frequency domain resources from the working frequency band of the wireless ad hoc network according to the physical layer measurement results as their respective working frequency band;

When the wireless ad hoc network supports multi-band transmission, each of the second subnet or the third subnet selects a working frequency band from the set of working frequency bands supported by the wireless ad hoc network according to the physical layer measurement result as the respective working frequency band.

Preferably, it specifically includes the following steps: (1) If the operating frequency bands selected by one first sub-network and one or more second sub-networks overlap, and there is an overlap between the first sub-network and at least one second sub-network When the minimum transmission distance is lower than the preset distance threshold, the first sub-network adopts a geographic location-based resource allocation scheme to allocate frequency domain resources;

(2) If the operating frequency bands selected by the two second sub-networks overlap, and the proportion of non-overlapping frequency domain resources of at least one second sub-network is not lower than the preset threshold, according to the The relationship between the minimum transmission distance and the preset distance threshold is used to allocate the respective frequency domain resources; if the proportion of the non-overlapping frequency domain resources of the two second subnets is lower than the preset threshold, the allocation is performed through resource competition or resource coordination. their respective frequency domain resources;

(3) If the working frequency bands selected by a target second sub-network and multiple second sub-networks overlap, and the minimum transmission distance between the target second sub-network and the multiple second sub-networks is lower than the preset distance threshold, according to The relationship between the ratio of the non-overlapping frequency domain resources in the target second sub-network and the preset threshold is used to allocate the respective frequency domain resources;

(4) If the operating frequency bands of a third sub-network and one or more third sub-networks overlap, and the minimum transmission distance with one or more of the third sub-networks is lower than the preset distance threshold, The third subnet that contains the largest number of communication nodes adopts the resource allocation scheme based on geographic location for frequency domain resource allocation; if there is a situation in which the set of nodes satisfying the preset distance threshold is empty in the resource allocation scheme based on geographic location, use The allocation method of step (2) or step (3) performs the allocation of respective frequency domain resources.

Preferably, in step (1) and step (4):

Part of the communication nodes in the first subnet or the third subnet using the geographic location-based resource allocation scheme form a set, and for other subnets whose operating frequency bands overlap with the first subnet or the third subnet, set The transmission distance between the communication nodes in the set and other sub-networks is not lower than the preset distance threshold, and the transmission between the communication nodes in the set allocates all the frequency domain resources of the working frequency band selected by the first sub-network or the third sub-network , the transmission between nodes not in the set allocates frequency domain resources other than the coincident frequency domain resources on the working frequency band selected by the first sub-network or the third sub-network;

If the other sub-network only includes one sub-network, the other sub-network can use all the frequency domain resources in the selected working frequency band.

Preferably, in step (2):

If the minimum transmission distance between the two second subnets is lower than the preset distance threshold, in the second subnet with a higher proportion of non-overlapping frequency domain resources, the transmission between communication nodes can allocate the frequency of the non-overlapping part of the frequency domain. In another second subnet, all the frequency domain resources on the working frequency band of the subnet can be allocated between communication nodes; if the minimum transmission distance between the two second subnets is not lower than the preset The distance threshold, the nodes in each second sub-network can use all the frequency domain resources of the respective working frequency bands for transmission.

Preferably, in step (3):

If the proportion of the non-overlapping frequency domain resources of the target second subnet is not lower than the preset threshold, then in the target subnet, the transmission between the communication nodes allocates the non-overlapping frequency domain resources;

If the proportion of the non-overlapping frequency domain resources of the target second subnet is lower than the preset threshold: when the proportion of the non-overlapping frequency domain resources of at least one sub-network in other second subnets is not lower than the preset threshold , and the proportion of frequency domain resources that overlap with the target second subnet is not lower than the difference between the preset threshold and the proportion of non-overlapping frequency domain resources of the target subnet, then the coincident resource with the highest proportion of coincident resources can be allocated to all The transmission between the communication nodes in the target second sub-network; when there is no other second sub-network that overlaps the target second sub-network, the frequency domain resource ratio is not lower than the preset threshold and the target sub-network. When the network does not overlap the difference in the ratio of frequency domain resources, the sum of the frequency domain resources of multiple other second subnets that only overlap with the target second subnet can be allocated to the communication nodes in the target second subnet When the proportion of non-overlapping frequency domain resources of no sub-network in other second sub-networks is not lower than the preset threshold, resource competition or resource coordination is used to allocate respective frequency domain resources.

Preferably, the resource competition can be implemented by a carrier sense multiple access/collision detection method, and the resource coordination can use overlapping frequency domain resources in a time division or frequency division manner.

The beneficial effects of the present invention are:

(1) Solve the problem of working frequency band selection after an ad hoc network is split into multiple subnets, which is an important step in the subnet splitting process;

(2) The mobility and flexibility of the wireless broadband ad hoc network are enhanced, and topology changes can be performed according to the actual situation to adapt to a wider range of application scenarios.

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.

Figure 1 is an example of a subnet split;

Figure 2 is a diagram of two examples of subnet splitting;

Fig. 3 is a sub-network frequency band selection example diagram of a single-band ad hoc network;

Fig. 4 is a sub-network frequency band selection example diagram of a multi-band ad hoc network;

5 is a schematic diagram of a resource allocation scheme based on geographic location;

FIG. 6 is an example diagram of resource allocation when two sub-networks 2/3 frequency domain resources overlap;

FIG. 7 is an example diagram of resource time division multiplexing when 2/3 frequency domain resources of two subnets overlap;

FIG. 8 is an example diagram of resource frequency division multiplexing when 2/3 frequency domain resources of two subnets overlap;

FIG. 9 is an example diagram of resource allocation when 2/3 frequency domain resources of three sub-networks overlap;

FIG. 10 is a flow chart of the selection of the working frequency band according to 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.

The present invention provides a method for selecting a working frequency band when a wireless ad hoc network performs sub-network splitting. From the results of the sub-network splitting, there are mainly two situations for the sub-network splitting:

The first sub-network is split: a wireless ad hoc network is split into a first sub-network and one or more second sub-networks, wherein the ratio of the number of communication nodes between the first sub-network and each of the second sub-networks is not lower than Preset proportional threshold 1, the ratio of the number of communication nodes in each second subnet is not higher than preset proportional threshold 2;

The second sub-network split: a wireless ad hoc network is split into two or more third sub-networks, wherein the ratio of the number of communication nodes in each third sub-network is not higher than the preset ratio threshold 2;

Among them, the preset ratio threshold 1 and preset ratio threshold 2 need to be specifically defined according to the network scale and the number of subnets. For example, the number of communication nodes in the wireless ad hoc network is 5, and it is divided into a first subnet and four second subnets. network, the preset ratio threshold 1 is not less than 4, for example, when the minimum number of communication nodes of the second subnet or the third subnet is not less than 5, the preset ratio threshold 2 can be set to 1.5;

The final result is that the first subnet has no less than 50% of the original ad hoc network communication nodes, and the scale of the second subnet is much smaller than that of the first subnet, but the scale difference between the second subnets is small; The three subnets have a small part of the nodes in the original ad hoc network. The scale of the third subnet and the original ad hoc network is quite different, but the scale difference between the third subnets is small;

According to the adopted wireless communication technical specifications, the wireless ad hoc network supports single-band or multi-band transmission. , there is usually a set containing multiple different working frequency bands, and different transmissions between nodes can use multiple different working frequency bands; The cost is low. However, due to the limited resources in the frequency domain, it is necessary to avoid interference through complex resource scheduling, and the transmission efficiency is low. No matter for single frequency band or multi frequency band, each continuous working frequency band needs to follow the wireless communication technical specifications. Provisions (for example, the frequency band bandwidth is a fixed value specified in the technical specification);

1. Specifically, for the first seed network split:

Regardless of whether the ad hoc network supports single frequency band or multi-frequency band, since the number of communication nodes between the first subnet and the original ad hoc network is not much different, the first subnet still uses the working frequency band of the original ad hoc network, which is different from the original ad hoc network. The working frequency band is consistent;

For a single-band ad hoc network, the specific steps are as follows:

(1) The second subnet independently selects a segment of frequency domain resources from the original working bandwidth as the working frequency band. When selecting the working frequency band, each second subnet can measure the SINR according to the physical layer (for example, measure the SINR on different frequency domain resources). or mutual information, etc.) results in selecting a frequency domain resource with better performance as the working frequency band; considering that the scale of the second sub-network is much smaller than the original ad hoc network, the selected working frequency band should match the network scale and be lower than the original The working frequency band is in line with the technical specifications; for example, the technical specification supports different working frequency band bandwidths such as 20M/10M/5M/3M. When the original working frequency band is 20M, the second subnet selects the 5M or 3M frequency domain resources as the working frequency band ;

After the working frequency band selection is completed, since the working frequency bands of all the second subnets overlap with the working frequency bands of the first subnet, the transmission in the first subnet may interfere with the transmission in the second subnet, considering that The split second subnet is usually in a moving state, and the distance between it and the first subnet is constantly changing; therefore, when the transmission distance between the second subnet and the first subnet When the distance between the boundary nodes is lower than the preset distance threshold, the first subnet adopts a resource allocation scheme based on geographic location; otherwise, the first subnet and the second subnet can use the overlapping frequency domain resources at the same time; The preset distance threshold is used to limit the distance between the nearest boundary nodes in different subnets. If the distance exceeds the preset distance threshold, it is considered that they do not interfere with each other. The specific value of the preset distance threshold needs to pass the network configuration and performance requirements. The measurement is obtained, and the measurement method is the prior art, which will not be described in detail here;

In the resource allocation scheme based on geographic location, some nodes in the first subnet are divided into a set, and the minimum transmission distance between each communication node in the set and the second subnet satisfies a preset distance threshold; For transmission between communication nodes in a subnet, as long as one of the sending and receiving nodes does not belong to the set, the same frequency domain resources as the working frequency band of the second subnet cannot be allocated for the transmission; if there are multiple second subnets at the same time , the first subnet needs to divide the node set for each second subnet, so that the minimum transmission distance between the nodes in the set and the corresponding second subnet meets the preset distance threshold; through this resource allocation method, it is possible to avoid Mutual interference between the first subnet and the second subnet.

(2) For different second subnets, if the operating frequency bands of the two second subnets overlap, and the proportion of non-overlapping frequency domain resources of at least one second subnet is higher than the preset threshold (this value needs to be determined according to the network (for example, the preset threshold is two-thirds), when the minimum transmission distance between two second subnets does not meet the preset distance threshold, the second subnet with a higher proportion of non-overlapping frequency domain resources In a subnet, the transmission between nodes can allocate frequency domain resources that do not overlap, while in another second subnet, the transmission between nodes can allocate all the frequency domain resources on the working frequency band of the subnet; when two second subnets The minimum transmission distance between networks satisfies the preset distance threshold, and the transmission of nodes in each second subnet can use all frequency domain resources of the working frequency band;

For different second subnets, if the proportions of non-overlapping frequency domain resources of the two second subnets are both lower than the preset threshold (in an extreme case, the operating frequency bandwidths of the two subnets are equal and completely coincident), through resource competition or Resource coordination is used to allocate respective frequency domain resources, that is, resource competition is realized by the carrier sense multiple access/collision detection (CSMA/CD) method in the prior art, and resource coordination is performed by time division or frequency division. Domain resources, in the time division mode, each subnet transmits data within the negotiated transmission time. In the frequency division mode, the two subnets negotiate and allocate the overlapping frequency domain resources, and each subnet uses the allocated frequency domain resources respectively;

(3) For different second subnets, if the working frequency band of one second subnet (this subnet is called the target second subnet) coincides with the working frequency bands of multiple (at least two) second subnets at the same time , and the minimum transmission distance with each second subnet does not meet the preset distance threshold;

If the proportion of the non-overlapping frequency domain resources of the target second subnet is higher than the preset threshold, the target subnet allocates the non-overlapping frequency domain resources for transmission between nodes;

If the proportion of the non-overlapping frequency domain resources of the target second sub-network is lower than the preset threshold, the following two situations are considered: 1. When there is at least one sub-network in the other second sub-networks that has a proportion of the non-overlapping frequency domain resources of the sub-network The ratio is higher than the preset threshold. If there are one or more second subnets that are higher than the threshold, the proportion of frequency domain resources that overlap with the target second subnet is not lower than the preset threshold and the target subnet does not overlap. When there is a difference in the proportion of frequency domain resources, the coincident resource with the highest proportion of coincident resources can be allocated to the node in the target second subnet for transmission; if there is no other second subnet, the target second subnet can be The resource ratio of the second subnet meets the preset threshold, then the sum of the frequency domain resources of multiple other second subnets that only overlap with the target second subnet can be allocated to the nodes in the target second subnet for transmission; 2 when other There is no sub-network in the second sub-network where the proportion of non-overlapping frequency domain resources is higher than the preset threshold, and for the part of repeated frequency domain resources, the corresponding second sub-networks use the resource competition or resource coordination scheme described above. Resource allocation;

For multi-band ad hoc networks:

The second subnet independently selects a working frequency band that meets the requirements of the technical specifications and matches the network scale from the set of supported working frequency bands. When selecting the working frequency band, each second subnet can select a better performance based on the physical layer measurement results. working frequency band;

If the working frequency band selected by the second sub-network overlaps with the working frequency band of the first sub-network, and the minimum transmission distance between the first sub-network and the second sub-network does not meet (ie, is lower than) the preset distance threshold, adopt the steps The geographical location-based resource allocation scheme in (1) avoids interference; it should be noted that if only part of the working frequency band of the second subnet is overlapped, the first subnet will avoid the overlapping when allocating resources for inter-node transmission. frequency domain resources;

If the working frequency bands of one second subnet and one or more other second subnets overlap, and the minimum transmission distance with each second subnet does not meet the preset distance threshold, then step (2) is adopted. Or the solution when the working frequency bands of the second subnet are coincident as described in step (3).

2. Specifically, for the second seed network split:

For a single-band ad hoc network, each third sub-network autonomously selects a segment of frequency domain resources from the working frequency band of the original ad hoc network as the working frequency band. When selecting the working frequency band, each third sub-network can measure the As a result, a frequency domain resource with better performance was selected as the working frequency band, and the selected working frequency band met the requirements of technical specifications and matched the network scale;

Considering that the scale of the third subnet may be larger than that of the second subnet, the operating frequency band of the third subnet is also relatively large, so the possibility of overlapping operating frequency bands of different subnets is high. When the working frequency bands of one or more third sub-networks overlap, and the minimum transmission distance with each third sub-network does not meet the preset distance threshold, the third sub-network with the largest network scale first adopts the first type of sub-network. The geographical location-based resource allocation scheme described in step (1) in the network allocation situation;

If the set of nodes that meet the preset distance threshold is empty in the geographic location-based resource allocation scheme, the second subnet described in step (2) or step (3) in the first type of subnet allocation is adopted. Solutions when working frequency bands overlap;

For a multi-band ad hoc network, the third subnet autonomously selects a working frequency band that meets the requirements of the technical specifications and matches the network scale from the set of supported working frequency bands. When selecting the working frequency band, each third subnet can The measurement result selects the working frequency band with better performance;

If the operating frequency bands of one third sub-network and one or more other third sub-networks overlap, and the minimum transmission distance between each third sub-network and each third sub-network does not meet the preset distance threshold, then step (2) or The solution when the operating frequency bands of the third sub-network overlap as described in step (3).

Further, in order to illustrate the solution of the present invention more clearly, it is assumed that there is a wireless ad hoc network including 10 communication nodes, and the wireless ad hoc network is split according to task requirements;

In the case of subnet splitting, the wireless ad hoc network is split into three subnets: subnet 1, subnet 2 and subnet 3, where subnet 1 and subnet 3 respectively contain 2 communication nodes, and subnet 2 contains 6 communication nodes. As shown in Figure 1. Subnet 2 contains 60% of the communication nodes of the original wireless ad hoc network, which is the first subnet. Subnet 1 and subnet 3 are both second subnets, that is, the communication between the first subnet and each second subnet is set. The ratio of the number of nodes is 3, and the ratio of the number of communication nodes of each second subnet is 1;

In the case of subnet split 2, the wireless ad hoc network is also split into three subnets: subnet 1, subnet 2, and subnet 3, where subnet 1 and subnet 3 contain 3 communication nodes respectively, and subnet 2 contains 4 communication nodes. As shown in Figure 2, the three subnets are all third subnets, that is, the ratio of the number of communication nodes in each third subnet is set to be no more than 1.5 at most.

It is assumed that the wireless communication technical specification stipulates four working bandwidths, namely 20MHz/10MHz/5MHz/3MHz, and the original wireless ad hoc network works on a working frequency band with a working bandwidth of 10MHz.

For the sub-network split case 1, since the sub-network 2 has 60% of the communication nodes of the original ad hoc network, the operating frequency band with a working bandwidth of 10 MHz is still selected. In the case of a single-band ad hoc network, only the 10MHz operating frequency band of the original wireless ad hoc network can be selected, as shown in (a) in Figure 3 . In the case of a multi-band ad hoc network, even if there are other working frequency bands with a working bandwidth of 10 MHz in the working frequency band set, in order to avoid the need for a large number of physical layer measurements to select a new working frequency band, Subnet 2 still selects the 10 MHz working frequency of the original wireless ad hoc network. frequency band, as shown in Figure 4.

For Subnet 1 and Subnet 3, it is assumed that the 3MHz working bandwidth can meet the network transmission use. In the case of a single-band ad hoc network, Subnet 1 and Subnet 3 are measured by the physical layer and work at 10MHz of the original wireless ad hoc network respectively. In the frequency band, the 3MHz frequency domain resource with the best performance is selected as the working frequency band. When selecting the working frequency band, the 10MHz frequency domain resources are first divided into multiple subbands with a bandwidth of 3MHz, and the two adjacent subbands are partially overlapped, and then Subnet 1 and Subnet 3 measure the signal-to-interference and noise ratio on each subband respectively ( SINR) or mutual information, and select the subband with the best measurement result as the working frequency band. Note that the measurements for Subnet 1 and Subnet 3 are not the same on the same subband. In the case of a multi-band ad hoc network, it is assumed that there are at least two working frequency bands with a bandwidth of 3MHz in the working frequency band set, then Subnet 1 and Subnet 3 respectively perform physical layer measurements on each 3MHz working frequency band, and select the best measurement result. The working frequency band is used as its own working frequency band. It should be noted that, whether it is a single-band or multi-band ad hoc network, the working frequency bands selected by the sub-network 1 and the sub-network 3 may overlap.

In the case of a single-band ad hoc network, the working frequency bands of Subnet 1 and Subnet 3 are part of the working frequency band of Subnet 2. If the minimum transmission distance between Subnet 1 and Subnet 2 is less than a predetermined threshold, then Subnet 1 Transmissions in Subnet 2 will interfere with transmissions in Subnet 2, and so will Subnet 3. In order to avoid the interference between the first sub-network (sub-network 2) and the second sub-network (sub-network 1 and sub-network 3), the geographical location-based resource allocation solution described in the inventive solution may be adopted. As shown in Figure 5, in subnet 2, the minimum transmission distance between the communication nodes in set 1 and subnet 3 is not lower than the predetermined threshold (but the minimum transmission distance from subnet 1 is lower than the predetermined threshold), in set 2 The minimum transmission distance between the communication node and the subnet 1 is not lower than the predetermined threshold (but the minimum transmission distance from the subnet 3 is lower than the predetermined threshold), so for the sending node and the receiving node in a transmission, as long as one party is not in the set 1 or set 2, the transmission cannot use the working frequency band F1 of subnet 1 and the working frequency band F3 of subnet 3, and if both the sender and the receiver are in set 1 or set 2, the transmission can use the working frequency of subnet 3. Band F3 or the operating band F1 of Subnet 1. Through this resource allocation method, interference between the first subnet (subnet 2) and the second subnet (subnet 1 and subnet 3) is avoided. In the case of a multi-band ad hoc network, if the operating frequency bands of the first sub-network (sub-network 2) and the second sub-network (sub-network 1 and sub-network 3) overlap, and the minimum transmission distance between the sub-networks is lower than the predetermined Threshold, and also adopts a resource allocation scheme based on geographic location to avoid interference.

When the working frequency bands of subnet 1 and subnet 3 overlap and the minimum transmission distance between the subnets is lower than the predetermined threshold, if the proportion of non-overlapping frequency domain resources of subnet 1 and/or subnet 3 is not less than 50% , then all transmissions in the sub-network with a higher proportion of non-overlapping frequency domain resources work in the frequency domain resources of the non-overlapping part, while all transmissions in the other sub-network work in the working frequency band of this sub-network, as shown in Figure 6 Show. If the proportion of non-overlapping frequency domain resources of subnet 1 and subnet 3 are both lower than 50%, according to the aforementioned solution of the present invention, subnet 1 and subnet 3 use the overlapping frequency domain resources through resource competition or resource coordination. In the resource competition mode, subnet 1 monitors the data transmission in subnet 3. If there is no data transmission in subnet 3 occupying the overlapping frequency domain resources at a certain transmission moment, then subnet 1 uses the overlapping frequency domain resources. . Otherwise, subnet 1 does not transmit data. Likewise, the Subnet 3 page listens for data transfers within Subnet 1. In the resource coordination mode, the subnet 1 and the subnet 3 exchange information and use the overlapping frequency domain resources through time division multiplexing or frequency division multiplexing. As shown in FIG. 7 , in the time division multiplexing mode, in the transmission time slot allocated to the subnet 1 (or the subnet 3), the subnet 1 (or the subnet 3) uses the overlapping frequency domain resources for data transmission. As shown in Figure 8, in the frequency division multiplexing mode, the overlapping frequency domain resources are divided into two parts, which are allocated to subnet 1 and subnet 3 respectively, and subnet 1 and subnet 3 use the allocated overlapping frequency domain resources respectively. data transfer.

In particular, as shown in Figure 9, there are three second subnets (subnet 1, subnet 2 and subnet 3), the operating frequency bands of subnet 2 coincide with those of subnet 1 and subnet 3, respectively, and subnet 2 is the same as The minimum transmission distance between subnet 1 and subnet 3 is below a predetermined threshold. If the proportion of non-overlapping frequency domain resources in subnet 2 is not less than 50%, all transmissions in subnet 2 work on the non-overlapping frequency domain resources, as shown in (a) of FIG. 9 . If the proportion of non-overlapping frequency domain resources in Subnet 2 is lower than 50%, but the proportion of non-overlapping frequency domain resources in Subnet 1 and Subnet 3 is not less than 50%, and the overlapping part 1 (or overlapping part 2) and the sub-network The ratio of the sum of the bandwidths of the non-overlapping frequency domain resources of 2 in the working frequency band of the sub-network 2 is not lower than the predetermined threshold. The transmission works on the non-overlapping frequency domain resources of the sub-network 1, the frequency domain resources of the overlapping part 1 are allocated to the sub-network 2, and the frequency-domain resources of the overlapping part 2 are allocated to the sub-network 3, as shown in (b) in Figure 9 . Considering the worse case, that is, the ratio of the sum of the bandwidths of the non-overlapping frequency domain resources of the overlapping part 1 and the sub-network 2 in the working frequency band of the sub-network 2 is still lower than the predetermined threshold, according to the aforementioned scheme of the present invention, the overlapping part 1 and The frequency domain resources of the overlapping part 2 are all allocated to the sub-network 2, and all transmissions in the sub-network 1 and the sub-network 3 work on their respective non-overlapping frequency domain resources.

For the second subnet split, the working frequency band selection scheme of the third subnet is similar to that of the second subnet. In the case of a single-band ad hoc network, each third sub-network (sub-networks 1 to 3) selects a segment of frequency domain resources with the best performance on the working frequency band of the original wireless ad hoc network by means of physical layer measurement. frequency band. In the case of a multi-band ad hoc network, each third sub-network (sub-networks 1 to 3) selects a working frequency band with the best performance from the set of working frequency bands as its own working frequency band by means of physical layer measurement.

If the operating frequency bands of one third sub-network and one or more other third sub-networks overlap, and the minimum transmission distance with each third sub-network is lower than the preset threshold, the third sub-network with the largest network scale The network adopts a geographic location-based resource allocation scheme to avoid interference. If in the resource allocation scheme based on geographic location, the set of nodes that meet the preset distance threshold is empty, it means that the resource allocation scheme based on geographic location cannot be used for one or more subnets. The solution when the working frequency bands of the second subnet are overlapped

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 (5)

1. A method for selecting working frequency band when wireless self-organizing network splits sub-network is characterized in that,

the wireless ad hoc network is split into a first sub-network and one or more second sub-networks or into two or more third sub-networks, wherein the ratio of the number of the communication nodes of the first sub-network to the number of the communication nodes of each second sub-network is not lower than a first preset ratio threshold, and the ratio of the number of the communication nodes of each second sub-network or each third sub-network is not higher than a second preset ratio threshold;

the first sub-network, the second sub-network and the third sub-network respectively select respective working frequency bands, and communication nodes in the sub-networks transmit data on the selected working frequency bands;

the first subnet selects the same working frequency band as the wireless ad hoc network;

when the wireless ad hoc network supports single-band transmission, each second subnet or third subnet selects a section of frequency domain resource from the working frequency band of the wireless ad hoc network as the respective working frequency band according to the physical layer measurement result;

when the wireless ad hoc network supports multi-band transmission, each second subnet or third subnet selects a working frequency band from a working frequency band set supported by the wireless ad hoc network as a respective working frequency band according to a physical layer measurement result;

the method specifically comprises the following steps:

(1) if the working frequency bands selected by one first subnet and one or more second subnets are overlapped, and the minimum transmission distance between the first subnet and at least one second subnet is lower than a preset distance threshold, the first subnet adopts a resource allocation scheme based on a geographic position to perform frequency domain resource allocation;

(2) if the working frequency bands selected by the two second subnets are overlapped and the proportion of the non-overlapped frequency domain resources of at least one second subnet is not lower than a preset threshold, distributing the respective frequency domain resources according to the relation between the minimum transmission distance between the two second subnets and the preset distance threshold; if the proportion of the non-coincident frequency domain resources of the two second subnets is lower than a preset threshold, distributing respective frequency domain resources in a resource competition or resource coordination mode;

(3) if the working frequency bands selected by a target second subnet and a plurality of second subnets are overlapped and the minimum transmission distance between the target second subnet and the plurality of second subnets is lower than a preset distance threshold, carrying out distribution of respective frequency domain resources according to the relation between the proportion of non-overlapped frequency domain resources in the target second subnet and the preset threshold;

(4) if the working frequency bands of one third subnet and one or more third subnets are overlapped and the minimum transmission distance between the third subnet and one or more third subnets is lower than a preset distance threshold, the third subnet with the largest number of communication nodes adopts a resource allocation scheme based on the geographic position to allocate frequency domain resources; and (3) if the node set meeting the preset distance threshold is empty in the resource allocation scheme based on the geographic position, allocating the respective frequency domain resources by adopting the allocation mode of the step (2) or the step (3).

2. The method for selecting the operating band in the subnet splitting of the wireless ad hoc network as claimed in claim 1, wherein in the step (1) and the step (4):

a part of communication nodes in a first subnet or a third subnet using a resource allocation scheme based on geographic position form a set, for other subnets which have working frequency bands coincident with the first subnet or the third subnet, the transmission distance between the communication nodes in the set and other subnets is not lower than a preset distance threshold, all frequency domain resources of the working frequency bands selected by the first subnet or the third subnet are allocated for transmission among the communication nodes in the set, and frequency domain resources except the coincident frequency domain resources on the working frequency bands selected by the first subnet or the third subnet are allocated for transmission among the nodes not in the set;

if the other sub-network only includes one sub-network, the other sub-network may use all frequency domain resources on the selected operating frequency band.

3. The method for selecting the operating band in the subnet splitting of the wireless ad hoc network as claimed in claim 1, wherein in the step (2):

if the minimum transmission distance between the two second subnets is lower than a preset distance threshold, in a second subnet with a higher proportion of non-coincident frequency domain resources, the transmission between the communication nodes can allocate non-repeated frequency domain resources, and in another second subnet, all frequency domain resources on the working frequency band of the subnet can be allocated between the communication nodes; if the minimum transmission distance between the two second subnets is not lower than the preset distance threshold, all frequency domain resources of respective working frequency bands can be used for node transmission in each second subnet.

4. The method for selecting operating band in subnet splitting of a wireless ad hoc network as claimed in claim 1, wherein in step (3):

if the proportion of the non-coincident frequency domain resources of the target second subnet is not lower than a preset threshold, the non-coincident frequency domain resources are transmitted and distributed among the communication nodes in the target subnet;

if the proportion of the non-coincident frequency domain resources of the target second subnet is lower than a preset threshold: when the proportion of the non-coincident frequency domain resources of at least one subnet in other second subnets is not lower than a preset threshold and the proportion of the frequency domain resources coincident with the target second subnet is not lower than the difference between the preset threshold and the proportion of the non-coincident frequency domain resources of the target subnet, the coincident resources with the highest proportion of the coincident resources can be allocated to the transmission between the communication nodes in the target second subnet; when the ratio of the frequency domain resources of one other second subnet superposed with the target second subnet is not lower than the difference between the preset threshold and the ratio of the frequency domain resources of the target subnet not superposed, the sum of the frequency domain resources of the other second subnets superposed with the target second subnet can be allocated to the transmission between the communication nodes in the target second subnet; and when the proportion of the non-coincident frequency domain resources of one subnet does not exist in other second subnets is not lower than a preset threshold, allocating the respective frequency domain resources by adopting a resource competition or resource coordination mode.

5. The method as claimed in claim 1 or 4, wherein the resource contention is implemented by carrier sense multiple access/collision detection method, and the resource coordination may use overlapped frequency domain resources in time division or frequency division manner.

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