CN114339660B - Unmanned aerial vehicle cluster random access method - Google Patents
Unmanned aerial vehicle cluster random access method Download PDFInfo
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Abstract
The invention discloses a random access method for an unmanned aerial vehicle cluster, and belongs to the field of unmanned aerial vehicle communication. The invention comprises two parts of designing standardized message mutual acknowledgement format and designing random access mechanism. The invention solves the problem of uncertainty generated when the sub-nodes of the unmanned aerial vehicle cluster are accessed and exited by designing the distributed high-dynamic random access protocol distributed on demand at the top layer of the unmanned aerial vehicle cluster, the dynamic resource management method based on the proportional fairness algorithm and the random access method, and effectively avoids the problem of a plurality of access request conflicts in the communication process. The invention can use the efficient time slot allocation method along with the change of task plan, task progress and strategic tactics to improve the performance of the TDMA protocol, quickly adjust the role played by each unmanned aerial vehicle and fairly and efficiently redistribute the occupied resources. The invention can control unmanned aerial vehicle cluster collaborative operation, and is suitable for the fields of military, agriculture, urban rescue, environmental survey, smart city and the like.
Description
Technical Field
The invention relates to an unmanned aerial vehicle cluster random access method, and belongs to the field of unmanned aerial vehicle communication.
Background
The unmanned aerial vehicle cluster is composed of a large number of miniaturized, cheap and high-mobility unmanned aerial vehicle nodes, the nodes are interconnected through a wireless self-organizing network technology, and the unmanned aerial vehicle cluster is constructed into a functional distributed intelligent system, has the advantages of remarkable operational efficiency, low cost, small damage loss, easiness in mass equipment and the like, and is a main trend of unmanned aerial vehicle development in the future. The distributed control mode of unmanned aerial vehicle cluster cooperative countermeasure breaks through the limitation of local perception and task execution of a single unmanned aerial vehicle, and plays an important role in application fields such as military, agricultural systems, urban rescue, environmental survey, smart cities and the like.
Currently, the mainstream unmanned aerial vehicle cluster networking technology includes relay network, star networking and mesh ad hoc network. The relay network is scattered with various types of aircrafts, so that a single aircraft can fly, and meanwhile, the aircrafts can be grouped into a network, and isolated nodes are integrated into a fight network through the relay unmanned aerial vehicle; in the star networking, communication takes a ground base station as a center, unmanned aerial vehicle terminals are scattered around the ground base station, the center ground base station is used for completing control of surrounding unmanned aerial vehicles, networking is realized, and the star networking system is suitable for scenes with fewer unmanned aerial vehicles and smaller execution task range; in a mesh network, each unmanned aerial vehicle is a node with the same function, one-hop or multi-hop routing is needed when the unmanned aerial vehicles communicate with each other, and when an unmanned aerial vehicle point cannot be linked to a ground central station in one hop, the unmanned aerial vehicle point can realize interconnection of all nodes in the whole network through multi-hop routing to the central station, but the communication architecture has no good robustness due to the semi-centralized characteristic of the network.
Due to the complexity of the unmanned aerial vehicle cluster structure and the diversity of behaviors, the load limit of a single unmanned aerial vehicle cannot complete cluster cooperative control, and a cluster cooperative decision control method based on a centralized or semi-centralized hierarchical architecture is not applicable any more. In addition, as the unmanned aerial vehicle clusters realize cooperative information sharing by virtue of the local communication capability of the unmanned aerial vehicle to complete the countermeasure task, lightweight requirements are also provided for communication protocols among clustered individuals. The existing unmanned aerial vehicle cluster access method tends to be complex, large in calculation amount and large in demonstration cost, so that unmanned aerial vehicle cluster cooperative countermeasure algorithm cannot demonstrate and verify on an actual unmanned aerial vehicle cluster, and the miniaturized random access method cannot effectively solve the problem of frequent access under a large number of nodes. Therefore, designing a method capable of meeting frequent access of a large number of unmanned aerial vehicles, reducing access conflicts and completing role optimization configuration becomes a key for realizing unmanned aerial vehicle cluster application.
Disclosure of Invention
Aiming at the requirement that unit unmanned aerial vehicles need to be frequently accessed and exited in the working process of an unmanned aerial vehicle cluster, and solving the problems of dynamic reassignment caused by role transformation and task change in the unmanned aerial vehicle cluster operation and conflict avoidance of simultaneous access requests sent by multiple nodes, the invention discloses an unmanned aerial vehicle cluster random access method, which aims at solving the uncertainty of deployment, use, network access, network exit and recovery of unmanned aerial vehicle cluster nodes, defining node task types and role division, realizing real-time adjustment and avoiding the problem of multiple access request conflicts in the communication process.
The invention aims at realizing the following technical scheme:
the invention discloses an unmanned aerial vehicle cluster random access method, which is a distributed high dynamic random access technology distributed according to requirements, and comprises two parts: firstly, designing a standardized message mutual-acknowledgement format, for an interconnection network without a center of an unmanned aerial vehicle cluster, adopting a Time Division Multiple Access (TDMA) technology, dividing time into different time slices (frames), dividing the frames into different time slots, uniquely distributing each time slot to a certain unmanned aerial vehicle node, and enabling each node to operate only in the time slot distributed to the node; and secondly, a random access mechanism is designed to avoid access conflict. The sending and receiving adopt response mechanism, the transmitting process announces the number of platforms currently accessed and the position of the reserved time slot through a broadcast time slot allocation table, the node to be accessed can send an access request in the reserved time slot, the system node judges the access request, if the access is permitted, the updated time slot allocation table is announced through the broadcast, and if the access is forbidden, the node to be accessed is announced through the broadcast to continue waiting or executing other operations. In the task process, a high-efficiency time slot allocation method is used along with the changes of task planning, task progress and strategic tactics so as to improve the performance of a TDMA protocol, rapidly adjust roles played by each unmanned aerial vehicle and fairly and efficiently redistribute resources occupied by each unmanned aerial vehicle.
The invention discloses an unmanned aerial vehicle cluster random access method, which comprises the following steps:
step 1: the random access protocol establishes a cluster node radio link.
The subset group network adopts a single channel mode, and fuses control instructions of a control channel into a data channel, namely, when a time slot is transmitted, a clock reference, a time slot allocation table, state data of a current node, control instructions of other nodes and task data of the current node are required to be transmitted. When one node transmits, all other nodes are in a receiving state.
Aiming at networking transmission requirements of different unmanned aerial vehicle types of remote control, telemetry and reconnaissance data of a cluster network under different application environments, a special-shaped platform message format is planned from the top layer, an information interaction mechanism is unified, and a physical interface is decoupled. In order to be compatible with different data occurrence rates and packet lengths, the method is suitable for multiple types of protocols, an elastic encapsulation frame protocol combining fixed length and variable length is used by adopting a packet mode such as packet service, encapsulation service and the like, and a fixed-length data frame is put into a data chain universal transmission frame by adopting a universal frame mode according to VMF message (Varible Message Foema, variable message format) and CCSDS (Consultative Committee for Space Data Systems, international spatial data system consultation committee) protocol standards.
Step 2: and random access criteria are distributed according to the requirement, so that the unmanned aerial vehicle nodes can smoothly access the network.
The sending and receiving adopt response mechanism, the transmitting process announces the number of platforms currently accessed and the position of the reserved time slot through a broadcast time slot allocation table, the node to be accessed can send an access request in the reserved time slot, the system node judges the access request, if the access is permitted, the updated time slot allocation table is announced through the broadcast, and if the access is forbidden, the node to be accessed is announced through the broadcast to continue waiting or executing other operations. The last time slot of each multi-frame in the receiving frame structure design is a fixed allocation time slot and is used for receiving a time slot reservation request, the first time slot in the sending frame structure design sends a time slot allocation information signaling, each time slot is divided into 1-k sub-time slots, and the k value is dynamically allocated by a central node in a cluster according to network load.
Step 3: aiming at the unmanned aerial vehicle cluster cooperative combat system, an improved generalized proportional fair (Generalized proportional fairness, GPF) method is used for realizing a resource scheduling strategy of the unmanned aerial vehicle cluster network communication system.
In addition, the GPF algorithm can overcome the defect that the traditional PF algorithm can only realize the speed fairness among short-term users, and realize the long-term fairness.
The proportion factors introduced by the GPF algorithm are the sum, and the tradeoffs of different degrees between the throughput of the system and the fairness of the user rate are flexibly adjusted by adjusting the values of a and b. The channel is divided into S RUs, each RU consisting of an equal number of unit slots, and the time domain multi-user transmission is in frames. And the user selects the user m with the maximum generalized proportional fairness factor on each RU for transmission. The generalized proportional fairness factor is defined as follows:
best user m on each RU * The selection rules of (a) are as follows:
wherein ,representing the instantaneous rate achieved by user m on RUs for the t-th frame, R, in relation to the channel conditions of user m during the t-th frame m (T) represents the historical average rate of user m over the duration of sliding window T, R, when ending at the T-th frame m The expression of (t) is as follows:
in the formula ,rm (T-1) represents the actual transmission rate of the last frame by the user m, and T represents the duration of the sliding window. When the system is initialized, the ratio of the scaling factors a and b is selected to influence the scheduling result of each frame, and different a/b values reflect the trade-off of different degrees between the throughput of the system and the fairness of the user rate.
Step 4: and optimizing throughput performance by setting a and b configuration values in the GPF scheduling method.
Step 5: and the time slot scheduling is completed in a shorter time by applying the time slot allocation method, so that collision-free data transmission is realized, and the channel utilization rate is improved to the greatest extent.
The complete process of TDMA protocol time slot allocation algorithm includes time slot selection, time slot application, time slot acknowledgement, and time slot release.
Time slot selection: in TDMA, the slot resources are marked in four states and are represented in binary, where 00 indicates that the current slot is in an idle state, 01 indicates that the current slot is occupied by the node, 10 indicates that the current slot is occupied by the master node, and 11 indicates that the current slot is occupied by other child nodes.
The maximum number of nodes allowed to be accommodated is N, the total data time slot amount of a single time frame is M, and each node can use an N×M two-dimensional matrix T= [ T ] ij ] N*M To store slot allocation information:
when selecting time slots, the node only needs to inquire a local time slot allocation matrix and then applies for occupying the time slots.
Time slot application and acknowledgement: the time slot allocation of TDMA protocols is a dynamic interactive process, the dynamics of which are mainly reflected in the two phases of time slot application and time slot acknowledgement. In the time slot application stage, the TDMA cycle monitors the traffic load of each node and other nodes on the communication link, and then calculates the number of data time slots required by the node in the current time frame, and the calculation formula is as follows:
b＝(1-θ)*d*r
in the formula, θ is the data slot overhead ratio, d is the duration of a single data slot, r is the data transmission rate of a node, and b is the number of bits that can be transmitted in a single data slot. In the formula, n is the total node number, t i And (3) the service load capacity is transmitted to the main node i by the node, and sn is the total data time slot amount required by the node.
If the number sn of the data time slots required by the node is more than 0, the node needs to sequentially apply for m idle data time slots in a local two-dimensional time slot allocation matrix, and send own time slot application information to the master node through a REQ packet. The master node receiving the REQ packet stores slot application information in a local two-dimensional slot matrix.
Time slot release: and a dynamic time slot allocation protocol is applied to meet the non-fixed requirement of the node on the occupation of time slot resources. When the node in the network no longer uses the time slot resources due to failure or service interruption, the occupied time slot is released, so that other nodes sending the service can acquire more time slot resources. And the two conditions of service interruption and node failure are respectively dealt with by adopting a mode of active time slot release and passive time slot release of a TDMA protocol. Active time slot release solves the problem of service interruption, and passive time slot release solves the node failure condition. And completing time slot release by actively transmitting release information through the child node and directly transmitting the release information through the master node.
The beneficial effects are that:
1. the invention discloses a random access method of an unmanned aerial vehicle cluster, which is compatible with a general dynamic time slot allocation protocol of a fixed time slot TDMA mode and a dynamic time slot TDMA mode, designs a minimum fixed time slot time frame structure, comprises the number of fixed time slots and forms a time frame module of the fixed structure. The dynamic time slot mode can be realized by simply stacking the time frame modules, thereby obviously reducing the complexity of the dynamic time slot allocation algorithm and simultaneously avoiding the problem of inflexible topological structure caused by fixed time slots
2. According to the unmanned aerial vehicle cluster random access method disclosed by the invention, random oscillation processing is carried out on access request time of each node, namely, the node randomly delays n multiframe periods to send requests from the moment of preparing access network, so that collision can be avoided in the next access with high probability even if collision occurs at a certain moment, and the probability that continuous collision cannot be accessed is greatly reduced.
3. The general PF algorithm only considers the historical average speed of users in a short time, and the sliding window time length considered by the GPF algorithm is far longer than the time length of a transmitting period, so that the speed fairness among users in a long time is ensured.
4. Aiming at networking transmission requirements of different unmanned aerial vehicle types of remote control, remote measurement and reconnaissance data of a cluster network under different application environments, the unmanned aerial vehicle cluster random access method disclosed by the invention plans a special-shaped platform message format from the top layer, unifies an information interaction mechanism, decouples a physical interface and improves the systematicness, compatibility, expansibility, inheritance and interoperability of group communication.
Drawings
Fig. 1 is a schematic diagram of a time slot reservation random access scheme of the present invention;
fig. 2 is a schematic diagram of a random network access flow of unmanned aerial vehicle nodes in the present invention;
FIG. 3 is a schematic diagram of multi-node network access conflict resolution in an example of the present invention;
FIG. 4 is a graph of system throughput for different a, b configurations in an example of the invention;
FIG. 5 is a graph of long term rate fairness VS system throughput in an example of the invention;
FIG. 6 is a graph of short-term rate fairness VS frame number in an example of the invention;
FIG. 7 is a flow chart of dynamic adjustment of unmanned node resources in an example of the invention;
fig. 8 is a flow chart of network operation in an example of the invention.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and examples. The technical problems and the beneficial effects solved by the technical proposal of the invention are also described, and the described embodiment is only used for facilitating the understanding of the invention and does not have any limiting effect.
As shown in fig. 2, the embodiment discloses a random access method for an unmanned aerial vehicle, which effectively solves the problems of cluster multipoint access conflict and optimal resource allocation in the current unmanned aerial vehicle cooperative countermeasure. In the example disclosed in this embodiment, the main flow of the overall operation of the unmanned aerial vehicle trunking communication network is shown in fig. 8, and mainly includes the stages of network initialization, application, authentication, network access, network shutdown, and the like.
Network initialization is the process of providing child nodes with enough initialization information to enable them to exchange information over the network and run the process. The network initialization process is completed through initialization parameter loading, and main initialization parameters comprise transmission parameters, network parameters, platform parameters and the like. After each sub node completes initialization, network operation is started according to the set network parameters. The common unmanned aerial vehicle node joins the network to run the process: after initializing the network, the child node receives the time message and completes network synchronization; when the child node prepares to access the network, sending an access application message to the master node; after receiving the application message, the master node judges whether the child node is allowed to access the network and responds; the child node processes according to the response result, if the response message is that the network access is not allowed, trying to access the network again or abandoning the network access; if the response message is that the network access is allowed, the message is sent and received according to the network protocol, and the network access is successful.
Network shutdown: after the task is completed, the unmanned aerial vehicle cluster master control node executes network closing operation and sends a network management message to the network sub-node. After the network child node receives the message, all communications in the network are stopped at the specified stop-run time.
As shown in fig. 2, the method for random access of the unmanned aerial vehicle cluster disclosed in the embodiment specifically includes the following implementation steps:
step 1: the random access protocol establishes a cluster node radio link.
And a universal dynamic time slot allocation protocol compatible with a fixed time slot TDMA mode and a dynamic time slot TDMA mode is used, and a minimum fixed time slot time frame structure is adopted, wherein the minimum fixed time slot time frame structure comprises the number of fixed time slots, so that a time frame module of a fixed structure is formed. The dynamic time slot mode can be realized through simple stacking of the time frame modules, so that the complexity of a dynamic time slot allocation algorithm is greatly reduced, and meanwhile, the problem of inflexible topological structure caused by fixed time slots is avoided. In order to be compatible with different data occurrence rates and packet lengths, the method is suitable for multiple types of protocols, and an elastic encapsulation frame protocol with a combination of fixed length and variable length is designed by adopting a packetization mode of packet service, encapsulation service and the like. According to VMF message and CCSDS (Consultative Committee for Space Data Systems, international Commission on consultation of data systems) protocol standard, adopting general frame mode to put fixed-length data frame into data chain general transmission frame.
The packetized transmission frame includes a preamble, a frame identification code, a cryptosync word and a data frame source packet. The source packets consist of packet header and packet data fields, both of which are necessary and arranged seamlessly. The length of the packet master header is fixed and the packet data field length is variable. In practical application, the length of a source packet is proper, the source packet is too short, and the transmission efficiency is low; the source packet is too long to be truncated into a multi-port transmission frame, the operation is complex, and the whole packet is easily lost due to errors, and the packet length is not more than three transmission frame data fields.
The universal time slot is mainly used for transmitting universal data such as service data, control instructions, state information and the like. Whereas the common time slots are mainly used for emergency signalling and random access applications, the common time slot frame structure is much shorter than the frame structure of the common time slots.
Step 2: and random access criteria are distributed according to the requirement, so that the unmanned aerial vehicle nodes can smoothly access the network.
The state of each slot node in fig. 1 is represented by a state (state), a target (target), which represents the state of the node in slot s, and a target which represents a one-hop neighbor node in slot s where the node is to transmit or receive a data packet. Thus, in time slot s, the state of a node can be divided into seven types:
transmission state (Transport) -at time slot s, the node sends a data packet to neighbor node a: (state=transport, target=a). If the packet transmitted by the node is a Broadcast packet, target=broadcast;
reception state (Receive) -at time slot s, a data packet is received from neighbor node b: (state=receive, target=b);
a transmission blocking state (block_t) -at time slot s, at least one of the neighbor nodes is receiving data packets from the other nodes, and no neighbor node is transmitting packets;
a receive blocking state (block_r) -at least one of the neighboring nodes has a packet being sent to the other node in time slot s, and no neighboring node is receiving the packet;
a block_tr-a time slot s in which at least one of the neighboring nodes is transmitting packets to other nodes, and in addition to that, at least one of the neighboring nodes is receiving packets from other nodes;
collision (Collision) -a node detects a Collision when receiving a packet;
idle state (Idle) -a node is Idle and no neighbor node is in a data packet transceiving state.
It should be noted that the target is only significant in the first two states, that is, in the transmission state and the reception state, and the states of the nodes are independent of each other, and a node can only be in one state in one time slot, and it can be considered that the time slots in which the node does not send data outwards can be called passive time slots.
Fig. 2 is a diagram of a random oscillation process for access request time of each node, which is aimed at the problem of conflict that a plurality of unmanned aerial vehicle nodes submit access applications at the same time, i.e. the nodes cannot send access applications each time, but randomly delay n multiframe period sending requests (n is a random number within a certain range) from the moment of preparing access to a network. The flow chart is shown in fig. 3.
Step 3: aiming at the unmanned aerial vehicle cluster cooperative combat system, an improved generalized proportional fair (Generalized proportional fairness, GPF) method is used for realizing a resource scheduling strategy of the unmanned aerial vehicle cluster network communication system.
The working steps of the improved generalized proportional fair scheduling method of the cluster network are as follows:
(1) When the unmanned aerial vehicle cluster node has resource application requirements, calculating a communication quality requirement index value of the node, and including the communication quality requirement index value in information sent by the unmanned aerial vehicle;
(2) The scheduler of the cluster network communication system resource evaluates the quality of each channel according to the channel detection reference signals transmitted by the unmanned aerial vehicle terminal;
(3) The scheduler of the cluster network communication system resource estimates the spectrum allocation system according to the channel quality information;
(4) Calculating the data transmission rate of each cluster node according to the spectrum allocation coefficient;
(5) The resource scheduler of the cluster network communication system comprehensively considers the instantaneous data transmission rate of the unmanned aerial vehicle and the fairness of the unmanned aerial vehicle to estimate the priority of each cluster node in each channel;
(6) Selecting the cluster node with the highest priority to perform resource scheduling of a cluster network communication system, and dividing the channel to the unmanned aerial vehicle node with the highest priority;
(7) Deleting the channels which are already allocated from the list of the candidate channel sets;
(8) If the list of the candidate channel set is empty, which indicates that the resource scheduling of all the trunking network communication systems is already allocated, the support of the algorithm is ended, otherwise, the step (3) is returned to continue to perform the resource scheduling and allocation of the trunking network communication systems.
According to the steps, corresponding service data packet transmission characteristic parameter values are adopted according to different resource types, different priorities, different time delays and different packet loss rates of the unmanned aerial vehicle cluster nodes. For the service with higher real-time requirement, the scheduler ensures the lowest bit rate for the service bearing; whereas for traffic with low real-time requirements, the scheduler does not need to guarantee the lowest bit rate for the bearer, so that in case of network congestion, the traffic needs to be subjected to a reduced rate arrangement. A default bearer and a special bearer are designed, wherein the default bearer is used for business data with small data volume and real-time property; and when the default bearer cannot meet the real-time requirement, enabling the special bearer to meet the speed and time delay requirements.
Step 4: and optimizing throughput performance by setting a and b configuration values in the GPF scheduling method.
By continuously optimizing the GPF scheduling algorithm policy, when the number of unmanned aerial vehicle cluster subgroup nodes given by combining fig. 4 and 5 is 30, the relation between the system throughput and the long-term (Δt=30sec) user rate fairness is provided. As can be seen, the GPF scheduler decreases with increasing rate fairness of a/b ratio, and when a=0, b=1, the GPF algorithm guarantees the lowest average rate user transmission, so the system has very high rate fairness, but the throughput is very low; it can also be observed that the conventional PF (a=1, b=1) scheduler is also unfair in terms of user rate fairness. In order to achieve a trade-off between throughput and user rate fairness, the GPF algorithm parameter settings a=1, b=3 or a=1, b=2 are suitable.
Fig. 6 illustrates the short-term user rate fairness as a function of frame number for a drone cluster subgroup node number of 30 in a drone cluster networking communication network. As can be seen from the figure, the GPF scheduler can improve the short-term rate fairness of users to a great extent compared with the MT scheduler (i.e. a=1, b=0), and the inter-plane rate fairness is even better than the RR scheduling algorithm. In addition, the GPF schedulers in the different a, b configurations also perform differently, and the conventional PF (a=1, b=1) schedulers perform slightly worse than the GPF schedulers in the a=1, b=2 configurations.
Step 5: and the time slot scheduling is completed in a shorter time by applying a time slot allocation algorithm, so that collision-free data transmission is realized, and the channel utilization rate is improved to the maximum extent.
In the time slot confirmation stage, in order to ensure that the time slot occupation does not conflict, the master node needs to perform unified arbitration aiming at the time slot application condition of each node, and the arbitration rule is as follows:
1) If the data time slot s is occupied by only one child node i, the time slot s is allocated to the node i for use.
2) If the data time slot s is occupied by a plurality of sub-nodes, the time slot s is preferentially distributed to the sub-nodes for transmitting the high-priority service for use; if the service priorities transmitted by the child nodes are the same, the time slot s is preferentially allocated to the child node with smaller node ID for use.
After the arbitration is finished, the main node broadcasts the arbitration result to all the sub-nodes through the ACK packet in the acknowledgement time slot. The node receiving the ACK packet needs to update its own local two-dimensional slot allocation matrix to prepare for the slot application of the next time frame.
Time slot release phase
TDMA protocols use active slot release and passive slot release to cope with both traffic interruption and node failure.
1) Active time slot release
A traffic timer is set for each node, and assuming that node i has no data transmission when the traffic timer expires, all the data slots occupied by that node before need to be released. At this time, the node i polls the local two-dimensional time slot allocation matrix, and modifies all time slot states with values of 1 in the ith row to 0, and the rest time slot states are unchanged. Then, waiting for the next control time slot to come, and sending the local two-dimensional time slot allocation matrix to the master node through the REQ packet.
2) Passive time slot release
If the master node does not receive its transmitted HELLO packet within a specified time, the default node i exits the system. At this time, each node needs to do the following operations: deleting the node i from the information table; polling respective two-dimensional time slot allocation matrixes, and resetting the time slot states of the ith row to 0; and waiting for the arrival of the next control time slot, and sending the respective two-dimensional time slot allocation matrix to the master node through a REQ packet.
Once released, the data slots return to the idle state and can therefore be re-applied for occupancy by nodes in the network. The TDMA effectively increases the time slot multiplexing rate through the time slot release process, so that the waste of channel resources is avoided, and the time slot adjustment flow is shown in fig. 7.
Thus, the unmanned aerial vehicle cluster access method is completed.
The foregoing detailed description has set forth the objects, aspects and advantages of the invention in further detail, it should be understood that the foregoing description is only illustrative of the invention and is not intended to limit the scope of the invention, but is to be accorded the full scope of the invention as defined by the appended claims.
Claims (3)
1. An unmanned aerial vehicle cluster random access method is characterized in that: comprises the following steps of the method,
step 1: establishing a cluster node wireless link by a random access protocol;
step 2: random access criteria are distributed according to the need to ensure that unmanned plane nodes smoothly access the network;
step 3: aiming at the unmanned aerial vehicle cluster cooperative combat system, an improved GPF method is used for realizing a resource scheduling strategy of an unmanned aerial vehicle cluster network communication system;
the implementation method of the step 3 is as follows:
the GPF algorithm can flexibly adjust the trade-off between the throughput of the system and the fairness of the user rate by introducing the scale factors with different ratios in the system initialization, and in addition, the GPF algorithm can overcome the defect that the traditional PF algorithm can only realize the fairness of the rate among short-term users and realize the fairness of the long-term;
the scale factors introduced by the GPF algorithm are a and b, and the compromise between different degrees of system throughput and user rate fairness is flexibly adjusted by adjusting the values of a and b; the channel is divided into S RUs, each RU is composed of equal number of unit time slots, and the time domain multi-user transmission is carried out by taking a frame as a unit; the user selects a user m with the maximum generalized proportional fairness factor on each RU for transmission; the generalized proportional fairness factor is defined as follows:
the selection rule for the best user m on each RU is as follows:
wherein ,representing the instantaneous rate that user m achieves over the RUs for the t-th frame, R, in relation to the channel conditions of user m during the t-th frame m (T) represents the historical average rate of user m over the duration of sliding window T, R, when ending at the T-th frame m The expression of (t) is as follows:
in the formula ,rm (T-1) represents the actual transmission rate of the last frame by the user m, and T represents the duration of the sliding window; system primaryDuring initialization, the ratio of the scaling factors a and b is selected to influence the scheduling result of each frame, and different a/b values reflect the trade-off of different degrees between the throughput of the system and the fairness of the user rate;
step 4: optimizing throughput performance by setting a, b configuration values in a GPF scheduling method;
step 5: the time slot scheduling is completed in a short time by applying the time slot allocation method, so that collision-free data transmission is realized, and the channel utilization rate is improved to the maximum extent;
the implementation method of the step 5 is that,
the complete process of the TDMA protocol time slot allocation algorithm comprises time slot selection, time slot application, time slot confirmation and time slot release;
time slot selection: in TDMA, the time slot resources are marked in four states and expressed in binary, where 00 indicates that the current time slot is in an idle state, 01 indicates that the current time slot is occupied by the node, 10 indicates that the current time slot is occupied by the master node, and 11 indicates that the current time slot is occupied by other child nodes;
the maximum number of nodes allowed to be accommodated is N, the total data time slot amount of a single time frame is M, and each node can use an N×M two-dimensional matrix T= [ T ] ij ] N*M To store slot allocation information:
when a node selects a time slot, only a local time slot allocation matrix is required to be inquired, and then the time slot is applied for occupation;
time slot application and acknowledgement: the time slot allocation of the TDMA protocol is a dynamic interactive process, and the dynamic property is mainly reflected in two stages of time slot application and time slot confirmation; in the time slot application stage, the TDMA cycle monitors the traffic load of each node and other nodes on the communication link, and then calculates the number of data time slots required by the node in the current time frame, and the calculation formula is as follows:
b＝(1-θ)*d*r
in the formula, theta is the data time slot overhead ratio, d is the duration of a single data time slot, r is the data transmission rate of a node, and b is the number of bits which can be transmitted by the single data time slot; in the formula, n is the total node number, t i Service load capacity is sent to a main node i by a node, and sn is the total amount of data time slots required by the node;
if the number sn of the data time slots required by the node is more than 0, the node needs to sequentially apply for m idle data time slots in a local two-dimensional time slot allocation matrix, and send self time slot application information to the master node through a REQ packet; the master node receiving the REQ packet stores the time slot application information in a local two-dimensional time slot matrix;
time slot release: the dynamic time slot allocation protocol is applied, so that the occupation non-fixed requirement of the node on time slot resources is met; when the node in the network does not use the time slot resources any more due to failure or service interruption, the time slot occupied by the node is released, so that other nodes sending the service can acquire more time slot resources; the two conditions of service interruption and node failure are respectively dealt with by adopting a mode of TDMA protocol active time slot release and passive time slot release; active time slot release solves the problem of service interruption, and passive time slot release solves the node failure condition; and completing time slot release by actively transmitting release information through the child node and directly transmitting the release information through the master node.
2. The unmanned aerial vehicle cluster random access method of claim 1, wherein: the implementation method of the first step is that,
the sub-group network adopts a single channel mode, and fuses control instructions of a control channel into a data channel, namely, when a time slot is transmitted, a clock reference, a time slot allocation table, state data of a current node, control instructions of other nodes and task data of the current node are required to be transmitted; when one node transmits, all other nodes are in a receiving state;
aiming at networking transmission requirements of different unmanned aerial vehicle types of remote control, telemetry and reconnaissance data of a cluster network under different application environments, a special-shaped platform message format is planned from the top layer, an information interaction mechanism is unified, and a physical interface is decoupled; in order to be compatible with different data occurrence rates and packet lengths, the method is suitable for multiple types of protocols, an elastic encapsulation frame protocol combining fixed length and variable length is used in a packet mode of packet service, encapsulation service and the like, and a data frame with fixed length is put into a data chain universal transmission frame in a universal frame mode according to a variable message format message and an international space data system consultation committee protocol standard.
3. The unmanned aerial vehicle cluster random access method of claim 1, wherein: the implementation method of the second step is that,
the sending and receiving adopt a response mechanism, the sending process announces the number of platforms which are currently accessed and the position of the reserved time slot through a broadcast time slot allocation table, the node to be accessed can send an access request in the reserved time slot, the system node judges the access request, if the access is permitted, the updated time slot allocation table is announced through the broadcast, and if the access is forbidden, the node to be accessed is announced through the broadcast to continue waiting or executing other operations; the last time slot of each multi-frame in the receiving frame structure design is a fixed allocation time slot and is used for receiving a time slot reservation request, the first time slot in the sending frame structure design sends a time slot allocation information signaling, each time slot is divided into 1-k sub-time slots, and the k value is dynamically allocated by a central node in a cluster according to network load.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101695144A (en) * | 2009-10-10 | 2010-04-14 | 中兴通讯股份有限公司 | Method supporting multi-service access and output and system thereof |
| CN104135743A (en) * | 2014-07-11 | 2014-11-05 | 西安交通大学 | Resource allocation method based on cache control in LTE-A (Long Term Evolution-Advanced) cellular network |
| CN109561513A (en) * | 2019-01-29 | 2019-04-02 | 四川九洲电器集团有限责任公司 | A kind of distribution Lothrus apterus ad hoc network multiple access protocol |
| CN111050337A (en) * | 2019-11-26 | 2020-04-21 | 中国运载火箭技术研究院 | Communication method and system of multi-user cluster networking system |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8385322B2 (en) * | 2007-07-30 | 2013-02-26 | Innovative Wireless Technologies, Inc. | Distributed ad hoc network protocol using synchronous shared beacon signaling |
| US20110158203A1 (en) * | 2009-12-31 | 2011-06-30 | Alvarion Ltd. | Proportional fair scheduling with packet transmission |
-
2021
- 2021-12-02 CN CN202111457463.7A patent/CN114339660B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101695144A (en) * | 2009-10-10 | 2010-04-14 | 中兴通讯股份有限公司 | Method supporting multi-service access and output and system thereof |
| CN104135743A (en) * | 2014-07-11 | 2014-11-05 | 西安交通大学 | Resource allocation method based on cache control in LTE-A (Long Term Evolution-Advanced) cellular network |
| CN109561513A (en) * | 2019-01-29 | 2019-04-02 | 四川九洲电器集团有限责任公司 | A kind of distribution Lothrus apterus ad hoc network multiple access protocol |
| CN111050337A (en) * | 2019-11-26 | 2020-04-21 | 中国运载火箭技术研究院 | Communication method and system of multi-user cluster networking system |
Non-Patent Citations (1)
| Title |
|---|
| 段新宇 ; 韩杏玲 ; 吴宣利 ; .LTE系统中基于缓存信息的非实时业务调度算法.哈尔滨工业大学学报.2016,(第11期),全文. * |
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