CN114679385B - LTP protocol parameter optimization configuration method for deep space communication network - Google Patents
LTP protocol parameter optimization configuration method for deep space communication network Download PDFInfo
- Publication number
- CN114679385B CN114679385B CN202210409917.1A CN202210409917A CN114679385B CN 114679385 B CN114679385 B CN 114679385B CN 202210409917 A CN202210409917 A CN 202210409917A CN 114679385 B CN114679385 B CN 114679385B
- Authority
- CN
- China
- Prior art keywords
- block
- ltp
- segment
- seg
- hop
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000004891 communication Methods 0.000 title claims abstract description 87
- 238000000034 method Methods 0.000 title claims abstract description 53
- 238000005457 optimization Methods 0.000 title claims abstract description 52
- 230000005540 biological transmission Effects 0.000 claims abstract description 111
- 238000012546 transfer Methods 0.000 claims abstract description 51
- 238000013461 design Methods 0.000 claims abstract description 30
- 238000004422 calculation algorithm Methods 0.000 claims abstract description 16
- 230000002776 aggregation Effects 0.000 claims description 30
- 238000004220 aggregation Methods 0.000 claims description 30
- 238000004364 calculation method Methods 0.000 claims description 13
- 235000008694 Humulus lupulus Nutrition 0.000 claims description 6
- 230000007246 mechanism Effects 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 3
- 230000006872 improvement Effects 0.000 description 12
- 239000013256 coordination polymer Substances 0.000 description 9
- 238000004088 simulation Methods 0.000 description 9
- 238000006116 polymerization reaction Methods 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000005538 encapsulation Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 230000000379 polymerizing effect Effects 0.000 description 2
- 230000001934 delay Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L67/00—Network arrangements or protocols for supporting network services or applications
- H04L67/01—Protocols
- H04L67/06—Protocols specially adapted for file transfer, e.g. file transfer protocol [FTP]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
- H04L41/08—Configuration management of networks or network elements
- H04L41/0803—Configuration setting
- H04L41/0823—Configuration setting characterised by the purposes of a change of settings, e.g. optimising configuration for enhancing reliability
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
- H04L41/14—Network analysis or design
- H04L41/145—Network analysis or design involving simulating, designing, planning or modelling of a network
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L67/00—Network arrangements or protocols for supporting network services or applications
- H04L67/2866—Architectures; Arrangements
- H04L67/30—Profiles
- H04L67/306—User profiles
Abstract
The application discloses an LTP protocol parameter optimization configuration method of a deep space communication network, which is used for a complex deep space communication network under a multi-hop scene, and comprises the following steps: establishing an LTP file transfer total time delay theoretical model of a complex deep space communication network according to a communication environment; based on an LTP file transfer total time delay model, an LTP parameter optimization design algorithm LTP-PODA is provided; and optimizing segment, block and session parameters in the LTP through an LTP-PODA algorithm to obtain a global optimal solution combination of the three parameters, thereby obtaining an LTP optimal parameter configuration scheme. The LTP transfer delay model of the complex deep space communication network established by the application has higher precision than the model established based on the prior simplified scene; the method configures reasonable LTP protocol parameters for the complex deep space communication network based on the DTN, and improves the LTP protocol transmission performance under complex scenes.
Description
Technical Field
The application belongs to the technical field of LTP protocol parameter configuration, and particularly relates to an LTP protocol parameter optimization configuration method of a deep space communication network.
Background
LTP (Licklider Transmission Protocol, LTP) is a DTN (Delay/Disruption Torlrant Network, DTN) protocol designed for point-to-point connections with extremely long propagation delays and with breaks, the main transmission protocol of DTN-based deep space communication networks.
Since different selection of protocol parameters can have a great influence on the transmission performance of the LTP, the configuration of the LTP protocol parameters is needed before the data transmission task using the LTP as the transport layer protocol, but no standard related to the configuration of the LTP protocol parameters is released at present. In order to obtain the highest possible performance of the deep space communication network using the LTP as a transmission protocol during data transmission, the parameter configuration of the LTP needs to be optimally designed.
However, the existing literature focuses on searching for a configuration scheme for optimizing LTP protocol parameters in a one-to-two-hop simplified scene in a simulation experiment mode. Such research results are not applicable in complex deep space communication networks in multi-hop scenarios, and the optimization methods proposed by the existing research are not general due to lack of theoretical work.
Therefore, in the future, a complex deep space communication network using LTP as a transmission protocol is needed to provide a general and convenient parameter optimization configuration method for LTP in different communication environments, so as to improve the data transmission performance of LTP.
Disclosure of Invention
The application aims to overcome the defects of the prior art and provides an LTP protocol parameter optimization configuration method of a deep space communication network.
In order to achieve the above objective, the present application provides a method for optimizing and configuring LTP protocol parameters of a deep space communication network, which is used for a complex deep space communication network in a multi-hop scenario, and the method comprises:
establishing an LTP file transfer total time delay theoretical model of a complex deep space communication network according to a communication environment;
based on an LTP file transfer total time delay model, an LTP parameter optimization design algorithm LTP-PODA is provided; and optimizing segment, block and session parameters in the LTP through an LTP-PODA algorithm to obtain a global optimal solution combination of the three parameters, thereby obtaining an LTP optimal parameter configuration scheme.
As an improvement of the above method, the communication environment includes: the deep space communication network comprises communication node types and numbers, downlink rates of links of each segment, BP hosting mechanism, aggregation time limit, file size, MTU, bundle aggregation rate of communication nodes, bundle size, single-pass time delay of different links, error rate and channel rate asymmetry ratio.
As an improvement of the above method, the LTP file transfer total delay theoretical model is:
T file_multihop ＝T former +T block_q_final +T latter +T aggre
wherein T is file_multihop LTP file transfer total time delay T for representing complex deep space communication network former Representing the starting of the file transfer from the source node to the block q_final Starting transmission at the q-th hop, which represents a hop with the longest single-pass link delay, block, in the entire complex deep space communication network q_final To finally complete the block of the transmission on the qth hop, T block_q_final Representing block q_final Transmission delay on the q-th hop, T latter Representing slave blocks q_final Time spent by transmission completion on the q-th hop until the destination node receives the entire file completely, T aggre Indicating the time spent by bundle aggregation.
As an improvement of the above method, the process for establishing the LTP file transfer total delay theoretical model of the complex deep space communication network specifically includes:
step s 1) determining the number of passes k experienced when only one block is passed on the ith hop min_i And the number of passes k experienced when passing the entire file max_i And calculate the average value k of the two mean_i ；
Step s 2) solving the time T for completing transfer of a single block on the ith hop block_i ；
Step s 3) calculating T of the previous (q-1) hop based on the calculation results obtained in step s 1) and step s 2) former Maximum total transmission delay T of single block in q-th transmission block_q_final T of the post (n-q) hop latter ；
Step s 4) dividing a file into N bundle Multiple bundles transmit, N bundle The multiple bundles are combined into N block A block;
when N is bundle >N block When the block is formed by polymerizing a plurality of bundles, the time T consumed by polymerizing the bundles into the block is calculated aggre The method comprises the steps of carrying out a first treatment on the surface of the When N is bundle ＝N block When bundle is in a non-aggregation state, T aggre ＝0；
Step s 5) summing the calculation results obtained in the step s 3) and the step s 4) to obtain the LTP file transfer total time delay theoretical model of the complex deep space communication network.
As an improvement of the above method, the step s 1) specifically includes:
the number of passes k experienced when only one block is passed on the ith hop is calculated according to min_i ：
Wherein p is seg_i Representing segment loss probability on the ith hop, N R Representing the number of red data segments contained in a block, m representing all theoretically possible transfer rounds;
the number of passes k experienced when passing the entire file is calculated according to max_i ：
Where f represents the red data duty ratio, N, in a single block to be transmitted bundle Representing a dimension L file Is divided into N bundle Multiple bundles transmit, L bundle_head Representing the length of the header of bundle, L block Representing the size of an individual block, L seg_payload_i Representing the load size of a single segment on the ith hop.
As an improvement of the above method, the step s 3) specifically includes:
the T of the previous (q-1) hop is obtained according to the following formula former ：
Wherein T is trans_a_mean 、T prop_a_mean And T ex_time_a_mean Respectively represent block q_final Average transmission time, average propagation time and average additional transfer time at hop a, T former_a Representing block q_final Average transfer total delay of transmission on the a-th hop, a e [1, q]；
The maximum total transmission time delay T of a single block in the q-th transmission is obtained according to the following method block_q_final ：
T block_q_final ＝T prop_q_final +T trans_q_final +T ex_time_q
Wherein T is prop_q_final 、T trans_q_final And T ex_time_q_final Respectively represent block q_final Propagation time, transmission time and additional delivery time at the q-th hop;
t of the post (n-q) jump is obtained according to the following formula latter ：
Wherein T is later_a The time interval from the time when the last block on the (a-1) hop finishes transmitting to the time when the last block on the a hop finishes transmitting is shown, and n shows the total number of hops through which data is transmitted from a source end to a destination end.
As an improvement of the method, the total time delay model is transferred based on the LTP file, and a LTP parameter optimization design algorithm LTP-PODA is provided; optimizing segment, block and session parameters in an LTP protocol through an LTP-PODA algorithm to obtain a global optimal solution combination of three parameters, thereby obtaining an LTP protocol optimal parameter configuration scheme; the method specifically comprises the following steps:
step t 1) initializing block and segment;
step t 2) obtaining local optimal solutions of the block and the segment according to the optimization basis of the block and the segment by using an iterative mode;
step t 3) judging whether a block and segment which minimize the total time delay of LTP file transfer are found, if so, obtaining a global optimal solution of the block and segment, and temporarily using the global optimal solution as an optimal value of the block and segment; turning to step t 4); otherwise, go to step t 2);
step t 4) comparing the obtained global optimal solution of the block with the actual block size in the data transmission process, thereby adjusting the optimal values of the block and segment obtained in the step t 3) to obtain the final optimal design values of the block and segment;
step t 5) obtaining an optimal design value of the session according to the optimization basis of the session, and combining the optimal design values of the block and the segment to obtain an LTP protocol optimal parameter configuration scheme.
As an improvement of the above method, the step t 1) specifically includes:
setting segment frame size L on each segment link seg_frame_a For setting value, the head length L of the combined segment seg_header Obtaining the load L of segment on each link according to the following formula seg_payload_a Thereby completing the initialization of segment:
L seg_payload_a ＝L seg_frame_a -L seg_header
will L seg_payload_a Give L seg_payload 、L seg_frame_a Give L seg_frame Substituting the block size L block Is the minimum value L of (2) b_min Thus completing the initialization of the block;
wherein L is RS_frame Representing the frame size of RS, L seg_payload Representing the load size, L, of segments seg_frame Representing segmentsFrame size, R data Representing the data transmission rate of the data channel, R ACK Representing the data transmission rate of the ACK channel;
as an improvement of the above method, the step t 2) specifically includes:
with L b_min For block size, substituting to find T former_a 、T block_q_final And T latter_a Will calculate the T file_multihop The problem of minimum segment size translates to T former_a (L seg_payload_a )、T block_q_final (L seg_payload_q ) And T latter_a (L seg_payload_a ) The problem of convex optimization of the function is solved, and the local optimal L meeting the first-order requirement of KKT on each section of link is obtained seg_payload_a *，L seg_payload_a * A local optimal solution for segment; wherein L is seg_payload_q Representing segment load size on the q-th hop;
will L seg_payload_a * Give L seg_payload Substituting the block size L of each section of link into the following formula to obtain the block size L of each section of link block Is the minimum value L of (2) b_min_a ：
L from each segment of link b_min_a The maximum value is given to L b_min ，L b_min Is the locally optimal solution of block.
As an improvement of the above method, the step t 5) specifically includes:
according to the following formula, the actual aggregate size L of the block in the data transmission process block_act Obtaining the optimal design value N of session sess_opt ：
N sess_opt ＝1.2×(L file /L block_act )。
Compared with the prior art, the application has the advantages that:
1. the application provides a set of LTP protocol parameter optimization configuration method of a general and easy-to-operate deep space communication network, which can be applied to a complex deep space communication network under a multi-hop scene, can be applied to a simplified one-to-two-hop simple deep space communication network, overcomes the defects of the traditional research provided method in scene applicability and expansibility, configures reasonable LTP protocol parameters for the complex deep space communication network based on DTN by utilizing the method, and improves the LTP protocol transmission performance under the complex scene;
2. the application establishes the LTP transfer delay model of the complex deep space communication network, and the model has higher precision than the existing model established based on the simplified scene, and is more suitable for the complex deep space communication network;
3. aiming at the problems that the protocol parameter optimization method proposed by the prior study has no generality and expansibility and cannot be applied to complex deep space communication scenes, the application provides the LTP protocol parameter optimization configuration method of the complex deep space communication network, which configures a proper parameter configuration scheme for the LTP, thereby improving the data transmission performance of the LTP in the complex deep space communication network;
4. the method of the application can conveniently and rapidly provide an optimal parameter configuration scheme for the LTP in different communication environments, and improves the data transmission performance of the LTP in the complex deep space communication network.
Drawings
Fig. 1 is a flowchart of an implementation of an LTP protocol parameter optimization configuration method for a deep space communication network according to the present application;
fig. 2 is a schematic diagram of three data transmission paths in a complex deep space communication network simulation scenario, wherein (a), (b), and (c) respectively represent the data transmitted by one, two, and three UNICON satellites (N U ＝1、N U ＝2、N U =3) forwarded data transmission path;
fig. 3 is a graph of block, segment, session values for an optimal parameter configuration scheme under different communication conditions;
FIG. 4 (a) is a graph showing comparison of LTP transmission performance under different error rate conditions with different parameter configuration schemes;
fig. 4 (b) is a comparison chart of LTP transmission performance under different link delay conditions, where different parameter configuration schemes are configured;
FIG. 4 (c) is a graph showing LTP transmission performance of different parameter configuration schemes under different channel rate ratio conditions;
fig. 4 (d) is a graph comparing LTP transmission performance of different parameter configuration schemes under bundle aggregation and non-aggregation conditions.
Detailed Description
The literature focuses more on LTP parameter optimization in one to two hop simplified scenarios, however, the research results are not applicable in complex deep space communication networks. The application firstly establishes an LTP transmission delay model of a complex deep space communication network, and then provides an LTP parameter optimization design algorithm of the complex deep space communication network based on the model, thereby configuring reasonable parameters for an LTP protocol to improve the transmission performance of the LTP. The method comprises the following steps:
step 1), establishing an LTP file transfer delay theoretical model of a complex deep space communication network.
Assuming that the whole LTP file is transferred through n hops, the one hop with the longest single-way delay is the qth hop, and the block which finishes the transmission last on the qth hop is the block q_final Consider the total delay of LTP file transmissions in complex deep space communication networks in both the bundle aggregation and non-aggregation cases. Based on the above assumptions and considerations, the LTP file transfer total delay of a complex deep space communication network is divided into four parts: from the beginning of file transmission at the source node to block q_final Starting transmission at the q-th hop, the time spent during this period; block block q_final Transmission delay on the q-th hop; from block q_final The time spent in the transmission on the q-th hop until the entire file is completely received by the destination node; time consumed by bundle aggregation. The sum of the four parts is the LTP file transfer delay theoretical model of the complex deep space communication network.
Step 1-1) dividing total LTP file transfer delay of a complex deep space communication network into four parts, namely T former 、T block_q_final 、T latter 、T aggre The theoretical model expression of the total delay is:
T file_multihop ＝T former +T block_q_final +T latter +T aggre (1)
wherein T is file_multihop Representing LTP file transfer time in a complex scene; t (T) former Representing the starting of the file transfer from the source node to the block q_final Starting transmission at the q-th hop, the time spent during this period; t (T) block_q_final Representing block q_final Transmission delay on the q-th hop; t (T) latter Representing slave blocks q_final The time spent from the completion of the transmission on the q-th hop to the complete reception of the entire file by the destination node; t (T) aggre Indicating the time spent by bundle aggregation.
Step 1-2) solving the number of transfer rounds experienced when only one block is transferred and the number of transfer rounds experienced when the whole file is transferred, and calculating the average value of the two;
step 1-3) the time spent for successful data transmission when a single block is transmitted is obtained;
step 1-4) calculating an average transfer total delay calculation T over a single block on a hop based on the calculation results obtained in step 1-2) and step 1-3) former 、T latter By calculating T from the maximum total transfer delay of a single block over a hop block_q_final Is a value of (2);
step 1-5) calculating T under both bundle polymerization and non-polymerization conditions aggre Is a value of (2);
and step 1-6), the sum of the results obtained in step 1-4) and step 1-5) is the LTP file transfer total time delay theoretical model of the complex deep space communication network.
Step 2) selecting segment, block, session in the LTP protocol parameters for optimal design.
Step 3) based on the theoretical model established in step 1), establishing optimization basis for block, segment, session respectively, thereby providing an LTP parameter optimization design algorithm (Parameter Optimization Design Algorithm for LTP, LTP-PODA). For a specific communication environment, substituting the environment condition parameters into the LTP-PODA to obtain the LTP protocol parameter configuration scheme which is most suitable for the communication environment.
Step 3-1), establishing an optimization basis of the block by taking the principle of 'avoiding delay waiting of acknowledgement information of the block on a forward link in an asymmetric channel';
step 3-2), solving the problem of segment size which minimizes the total transmission delay of the LTP file, converting the problem into a convex optimization problem, and establishing an optimization basis of segment;
step 3-3), establishing an optimization basis of the session by taking the principle that the number of the session can enable all data to be transmitted to be sent at one time;
step 3-4) according to the optimization basis of block, segment, session provided in step 3-1), step 3-2) and step 3-3), an LTP parameter optimization design algorithm (LTP-PODA) is provided, and the three protocol parameters are optimally designed. Firstly, initializing a block and segments; then, by using an iterative mode, solving a local optimal solution of the block and the segment according to an optimization basis of the block and the segment until the block and the segment which can minimize the total transmission delay of the LTP file are found to be used as a global optimal solution; on the basis, the values of the obtained block and segment optimal solutions are adjusted according to the actual block size, so that optimal design values of the block and segment are obtained; finally, according to the optimization basis of the session, the optimization design value of the session is obtained;
step 3-5) combining the optimal design values of the three parameters obtained in the step 3-4) into an LTP optimal parameter configuration scheme in the complex deep space communication network.
Step 4) configuring the optimal parameter configuration scheme obtained in the step 3) for the LTP protocol for executing data transmission in the complex deep space communication network, so as to realize the improvement of the data transmission performance of the whole network.
The technical scheme of the application is described in detail below with reference to the accompanying drawings and examples.
Example 1
As shown in fig. 1, embodiment 1 of the present application proposes an LTP protocol parameter optimization configuration method for a deep space communication network.
1. Establishing LTP file transfer delay theoretical model of complex deep space communication network
The LTP file transfer delay theory model can be expressed as:
T file_multihop ＝T former +T block_q_final +T latter +T aggre (1)
wherein T is file_multihop Representing LTP file transfer time in a complex scene; t (T) former Representing the starting of the file transfer from the source node to the block q_final The transmission is started at the q-th hop, the time consumed in the transmission is the one with the longest single-way delay, the block q_final A block for the last completed transmission on the q-th hop; t (T) block_q_final Representing block q_final Transmission delay on the q-th hop; t (T) latter Representing slave blocks q_final The time spent from the completion of the transmission on the q-th hop to the complete reception of the entire file by the destination node; t (T) aggre Indicating the time spent by bundle aggregation.
1) Calculating the number of transmission rounds;
a. calculating the number of passes experienced when only one block is passed
The LTP protocol uses a block as a transmission unit to perform data transmission, during which the block is divided into multiple segments, so that the number of transmission rounds undergone by a block transmission is determined by the maximum value of the number of transmission rounds undergone by all segments in the block, i.e., G block ＝G seg_max The application adopts G block To calculate the number of passes k experienced when only one block is passed on the ith hop min_i ：
Wherein k is min_i Representing the number of passes, p, experienced when only one block is passed on the ith hop seg_i Representing segment loss probability on the ith hop, N R The number of red data segments contained in one block is indicated.
Wherein N is R Is calculated as follows. LTP provides two transmission mechanisms-reliable and unreliable transmission, distinguished by the aggregation of red and green data segments in the LTP block. The red data segment represents the segment of data and the green data segment represents the segment of dataAn unreliable transmission mode is employed. Assuming that in a single block to be transmitted, the red data duty ratio is f, the green data duty ratio (1-f), then the number of red data segments contained in one block is N R ＝(L block ×f)/L seg_payload Wherein L is block Representing the size of an individual block, L seg_payload Representing the load size of a single segment.
b. Calculating the number of passes experienced when passing an entire file
Let a size L file The file is divided into N bundle Transmitting the bundles, and packaging the bundles by BP (BP) to combine into N block Each block is N in common block ＝(L file +L bundle_head ×N bundle )/L block Each block transmits, and each block occupies a session according to the transmission mechanism of the LTP, namely N is needed in total block And (5) individual session. Wherein L is bundle_head Representing the length of the header of a bundle after BP encapsulation. The number of passes k experienced by passing the entire file on the ith hop max_i The calculation formula of (2) is as follows
In which L seg_payload_i Representing the load size of a single segment on the ith hop.
c. Calculating the mean value k of the results of steps a, b mean_i The formula is as follows:
k mean_i ＝(k min_i +k max_i )/2 (4)
2) Calculating the total time delay of the single block for completing transmission on one hop;
the total delay of single block transfer consists of three parts: the transmission time, propagation time and extra transfer time consumed in the retransmission of CP (CP) Segment and RS (Report Segment) due to the loss of CP Segment and RS, respectively, are calculated as follows:
a. calculating the transmission time of a single block on a hop
A block is divided into segments for transmission, and if a segment is transmitted while following a geometric probability distribution, the probability of success of the mth transmission is P seg_m ＝p seg m-1 ×(1-p seg ) Wherein p is seg Representing the loss probability of segments, the expected value of the total number of transmissions per segment on the ith hop is:
since the data transmission rate of each hop of the path is not necessarily the same when data is transmitted in the network, R is set to data_i Representing the data transmission rate of the data channel when the data is transmitted in the ith hop, the transmission time T of the block in the ith hop trans_i The calculation formula of (2) is as follows:
wherein L is seg_frame_i Represents the size of a segment (including the header information size of each underlying protocol encapsulation) when transmitted on the physical channel on the ith hop.
b. Calculating propagation time of single block on one hop
Propagation time T prop Mainly by successful transmission of N R The number of passes that are experienced at each segment, k (k.gtoreq.1). Since the single-pass time delay of each hop of the path is not necessarily the same when data is transmitted in the network, let T delay_i Representing the single pass delay of data transmitted over the ith hop link, the propagation time T of a single block over the ith hop prop_i The formula of (2) is as follows:
wherein L is RS_frame Representing the size of an RS at the time of physical channel transmission(including header information size at the time of encapsulation of each underlying protocol), R ACK_i Indicating the data transmission rate of the ACK channel on the i-th hop.
c. Calculating additional transfer time of single block on one hop
The CP segment or RS loss may cause the corresponding timer to expire, which may cause the retransmission of the CP segment or RS, and the time consumed by the timer to expire may cause the entire transmission time to be additionally increased. Assume that the timer expires for a time T ex (T ex ＝2T delay +β, where β is a fixed value and includes at least the transmission time of RS). Let p be CP_i 、p RS_i Respectively representing the loss probability of the CP section and the RS on the ith hop, wherein the loss probability of the CP section or the RS on the ith hop is p CP_RS_i ＝1-(1-p CP_i )×(1-p RS_i ). From this, the expected value of the sum of the number of transmissions of each CP segment and RS on the ith hop can be calculated:
the extra transfer time T consumed due to the loss of CP segment and RS ex_time_i Is calculated as follows:
d. the single block completes the total delay T of the transfer on the ith hop block_i The method comprises the following steps:
T block_i ＝T trans_i +T prop_i +T ex_time_i (10)
3) Calculate T former 、T block_q_final 、T latter Is a value of (2);
a. calculate T former
Will T former Dividing into T according to the number of hops before (q-1) former_1 、T former_2 、…T former_a 、…、T former_q-1 A total of (q-1) parts, each of which contains an average of the transmissions of a block over the hopThe total delay is transferred. Since the total transmission delay of a single block consists of three parts of transmission time, propagation time and additional transmission time, the average total transmission delay of a block transmitted on the a-th hop consists of the average transmission time T trans_a_mean Average propagation time T prop_a_mean And average additional transfer time T ex_time_a_mean The composition is calculated as follows:
then T is former The calculation formula of (2) is as follows:
b. calculate T block_q_final
T block_q_final The value of (2) is the maximum total transfer delay for a single block to transmit on the q-th:
c. calculate T latter
For T latter It can also be divided into T according to the number of hops of the following (n-q) hops (where n represents the total path of data from source end to destination end latter_q+1 、T latter_q+2 、…T latter_a 、…、T latter_n A total of (n-q) parts, each of which also contains the average total delay of the transmissions of a block over the hop, T latter Is calculated as follows:
4) Calculating T under both bundle aggregation and non-aggregation conditions aggre Is a value of (2);
suppose a textThe pieces being divided into N bundle Multiple bundles are transmitted, and these bundles are combined into N block Block, when N bundle >N block When it means that a block is formed by aggregation of multiple bundles, and when N bundle ＝N block When a block contains only one bundle, the bundle is in a non-aggregation state. Let the time consumed for the bundle to aggregate into blocks be T aggre 。
In the aggregation state, the aggregation time is mainly affected by the rate lambda of each communication node in processing the aggregation operation, assuming that omega represents the aggregation time of blocks on a single node, t lim Indicating the longest aggregation time set by the LTP protocol, then T aggre The calculation formula is deduced as follows:
in the non-polymerized state, i.e. N bundle ＝N block In the case of polymerization, the polymerization time is 0, T aggre The method comprises the following steps:
T aggre ＝0 (17)
5) Calculating the total transmission time delay of the LTP file of the complex deep space communication network;
LTP file transfer total time delay T of complex deep space communication network file_multihop From T former 、T block_q_final 、T latter 、T aggre Four parts are formed, T file_multihop The calculation formula is as follows:
T file_multihop ＝T former +T block_q_final +T latter +T aggre (18)
t in former 、T block_q_final 、T latter 、T aggre Can be obtained from the calculation results of the steps 1) to 4).
2. Optimizing parameter selection
Parameters in the LTP protocol with the greatest influence on the performance of the LTP protocol comprise the size of block, the size of segment and the number of segments, and therefore the three parameters are selected for optimal design.
3. Parameter optimization design and optimal configuration scheme selection
1) Establishing a block optimization basis
When LTP transmits data, the acknowledgement information RS is sent in units of blocks, namely one block corresponds to one RS, and in order to cope with the asymmetric characteristic of a link in a deep space communication environment, delay waiting of the acknowledgement information RS of the block on a forward link is avoided, and the sending time of the block is longer than the sending time of the RS. In addition, LTP specifies that the block is segmented into segments and then subsequently transmitted, so that the block size should be at least greater than the segment size, and then the block optimization is based on the following:
2) Establishing segment optimization basis
The segment selection problem can be converted into a convex optimization problem with the following expression:
wherein L is seg_payload_a Indicating the load size, L, of segments on the a-th hop seg_header Representing the header information size of the segment. For each section of link before the link with the highest time delay of the single-way link in the process of data transmission, T a (L seg_payload_a )＝T former_a (L seg_payload_a ) The method comprises the steps of carrying out a first treatment on the surface of the For the link with the largest single-path link time delay, T a (L seg_payload_a )＝T block_q_final (L seg_payload_q ) The method comprises the steps of carrying out a first treatment on the surface of the T for each segment of links after the link with the largest time delay of the routed single-way links a (L seg_payload_a )＝T latter_a (L seg_payload_a )。In addition, L MTU Indicating the MTU size, L, of the link layer MTU =1500 bytes; due to L block Is typically larger than the MTU, so here L can be ignored block Size constraints.
The optimal solution of the convex optimization problem should meet the first-order requirement of Karush-Kuhn-Tucker (KKT), and let the KKT multiplier be mu 1 *，μ 2 * Solving the segment optimal solution L on each segment of link seg_payload_a * The formula of (2) is as follows:
3) Establishing session optimization basis
Considering two cases of bundle aggregation and non-aggregation, the calculation formula of the optimization design of session is as follows:
N sess_opt ＝1.2×(L file /L block_act ) (23)
in which L block_act Represents the actual aggregate size of the block, N sess_opt Representing the optimal selection value of session.
4) LTP parameter optimization design algorithm (LTP-PODA)
The LTP-PODA algorithm is as follows:
first step, let L on each link seg_frame_a =1500 bytes, substituting this into (19) to obtain L block Is the minimum value L of (2) b_min ；
Second, L is b_min Substituting equations (12), (13) and (14), and finding out the local optimum L meeting the first-order requirement of KKT on each link by solving equation (21) seg_payload_a * This is the locally optimal solution for segment; l is obtained from the formula (21) seg_payload_a * Substituting (19) to obtain minimum value L of block size on each link b_min_a And takes the maximum value of the values to give L b_min This is blockA local optimal solution;
third step, judging whether to find the T-shaped part file_multihop Minimum L seg_payload_a *、L b_min Numerical value, if so, let the final L seg_payload_a *、L b_min The values are respectively L segment_opt_temp 、L block_opt_temp And transferring to a fourth step; if not, turning to a second step;
fourth, calculate L according to equation (22) block_act And combine it with L block_opt_temp Comparing if L block_act ＝L block_opt_temp The optimal design value of block and segment is L segment_opt ＝L segment_opt_temp 、L block_opt ＝L block_opt_temp The method comprises the steps of carrying out a first treatment on the surface of the If L block_act <L block_opt_temp The optimal design value of block is L block_opt ＝L block_opt_temp But because the actual block size is L block_act Thus will L block_act Substituting the formulae (12), (13) and (14) and then solving the formula (21) to obtain a new L seg_payload_a * Optimizing design value L for segment segment_opt ；
Fifthly, obtaining an optimal design value N of the session according to the formula (23) sess_opt 。
5) Obtaining LTP parameter optimization configuration schemes under different communication environments
Substituting the environmental conditions into LTP-PODA for different communication environments to obtain L block_opt 、L segment_opt 、N sess_opt The values are combined to form an optimal configuration scheme of the LTP parameters in the communication environment.
4. And (3) configuring the optimal parameter configuration scheme obtained in the step (5) in the step (3) for the LTP protocol for executing data transmission in the complex deep space communication network, thereby realizing the improvement of the data transmission performance of the whole network.
The technical effect of the application is shown by simulation.
The simulation scenario is as follows:
the simulation scene is a complex deep space communication network scene of Mars-UNICON-GEO-Earth (Universal inter-satellite communication network, universal Interplanetary Communication Network, UNICON);
the network comprises 1 Mars detector, 6 UNICON satellites, 1 GEO satellite and 1 ground station, nine communication nodes are all included, a data transmission path diagram is shown in figure 2, wherein U1-U6 represent six UNICON satellites;
the simulation parameter configuration is shown in table 1.
Table 1 simulation experiment parameter configuration of LTP protocol parameter optimization configuration method of complex deep space communication network
Under the complex deep space communication network scene, according to different link environments shown in table 1, the configuration method provided by the application is utilized to provide a parameter configuration optimization scheme under a corresponding scene for the LTP, and performance comparison is carried out with other parameter configuration schemes under different environments, so that the effectiveness of the configuration method provided by the application in the aspect of LTP performance improvement is verified.
The simulation experiment designs 8 configuration schemes in total. Scheme 1 represents a parameter configuration scheme in which all three parameters are optimized. Scheme 2, scheme 3, scheme 4 represent schemes that are not optimized for block or segment only, respectively. Scheme 5, scheme 6, scheme 7 represent schemes where only block or segment or session is optimized, respectively. Scheme 8 represents a scheme in which none of the three parameters are optimized.
In schemes 2-8, 500KB is chosen as the unoptimized size of the block, L is chosen MTU -100 = 1400bytes as unoptimized segment size, if L block =1 bundle, then 1/2× (L file /L block ) (wherein L block And L is equal to block_act Equal) to calculate N sess The value is used as the unoptimized session number value, if L block >1bundle, then 1.2× (L file /L block )(L block ≠L block_act ) Calculating N sess As an unoptimized value for session. Optimization of block, segment, session in different link environmentsThe values are obtained by the configuration method according to the present application, as shown in fig. 3.
Simulation results: FIG. 4 (a) is a graph showing comparison of LTP transmission performance of different parameter configuration schemes under different error rate conditions; fig. 4 (b) is a comparison chart of LTP transmission performance under different link delay conditions, where different parameter configuration schemes are configured; FIG. 4 (c) is a graph showing LTP transmission performance of different parameter configuration schemes under different channel rate ratio conditions; fig. 4 (d) is a comparison graph of LTP transmission performance under bundle aggregation and non-aggregation conditions, with different parameter configuration schemes. As can be seen from the four diagrams, in any link environment, the LTP parameter optimization configuration scheme obtained by using the parameter configuration method of the present application is configured to the LTP, and compared with other parameter configuration schemes configured for the LTP, better transmission performance can be obtained.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present application and are not limiting. Although the present application has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present application, which is intended to be covered by the appended claims.
Claims (6)
1. An LTP protocol parameter optimization configuration method for a deep space communication network, which is used for a complex deep space communication network in a multi-hop scene, comprises the following steps:
establishing an LTP file transfer total time delay theoretical model of a complex deep space communication network according to a communication environment;
based on an LTP file transfer total time delay model, an LTP parameter optimization design algorithm LTP-PODA is provided; optimizing segment, block and session parameters in an LTP protocol through an LTP-PODA algorithm to obtain a global optimal solution combination of three parameters, thereby obtaining an LTP protocol optimal parameter configuration scheme;
the communication environment includes: the deep space communication network comprises communication node types and numbers, downlink rates of links of each section, BP hosting mechanisms, aggregation time limit, file size, MTU, bundle aggregation rate of communication nodes, bundle size, single-pass time delay of different links, error rate and channel rate asymmetry ratio;
the LTP file transfer total time delay theoretical model is as follows:
T file_multihop ＝T former +T block_q_final +T latter +T aggre
wherein T is file_multihop LTP file transfer total time delay T for representing complex deep space communication network former Representing the starting of the file transfer from the source node to the block q_final Starting transmission at the q-th hop, which represents a hop with the longest single-pass link delay, block, in the entire complex deep space communication network q_final To finally complete the block of the transmission on the qth hop, T block_q_final Representing block q_final Transmission delay on the q-th hop, T latter Representing slave blocks q_final Time spent by transmission completion on the q-th hop until the destination node receives the entire file completely, T aggre Represents the time spent by bundle aggregation;
the establishing process of the LTP file transfer total time delay theoretical model of the complex deep space communication network specifically comprises the following steps:
step s 1) determining the number of passes k experienced when only one block is passed on the ith hop min_i And the number of passes k experienced when passing the entire file max_i And calculate the average value k of the two mean_i ；
Step s 2) solving the time T for completing transfer of a single block on the ith hop block_i ；
Step s 3) calculating T of the previous (q-1) hop based on the calculation results obtained in step s 1) and step s 2) former Maximum total transmission delay T of single block in q-th transmission block_q_final T of the post (n-q) hop latter ；
Step s 4) dividing a file into N bundle Multiple bundles transmit, N bundle The multiple bundles are combined into N block A block;
when N is bundle >N block When it is indicated that a block is composed ofMultiple bundles are aggregated, and the time T consumed by the aggregation of the bundles into blocks is calculated aggre The method comprises the steps of carrying out a first treatment on the surface of the When N is bundle ＝N block When bundle is in a non-aggregation state, T aggre ＝0；
Step s 5) summing the calculation results obtained in the step s 3) and the step s 4) to obtain an LTP file transfer total time delay theoretical model of the complex deep space communication network;
the total time delay model is transferred based on an LTP file, and an LTP parameter optimization design algorithm LTP-PODA is provided; optimizing segment, block and session parameters in an LTP protocol through an LTP-PODA algorithm to obtain a global optimal solution combination of three parameters, thereby obtaining an LTP protocol optimal parameter configuration scheme; the method specifically comprises the following steps:
step t 1) initializing block and segment;
step t 2) obtaining local optimal solutions of the block and the segment according to the optimization basis of the block and the segment by using an iterative mode;
step t 3) judging whether a block and segment which minimize the total time delay of LTP file transfer are found, if so, obtaining a global optimal solution of the block and segment, and temporarily using the global optimal solution as an optimal value of the block and segment; turning to step t 4); otherwise, go to step t 2);
step t 4) comparing the obtained global optimal solution of the block with the actual block size in the data transmission process, thereby adjusting the optimal values of the block and segment obtained in the step t 3) to obtain the final optimal design values of the block and segment;
step t 5) obtaining an optimal design value of the session according to the optimization basis of the session, and combining the optimal design values of the block and the segment to obtain an LTP protocol optimal parameter configuration scheme.
2. The method for optimizing configuration of LTP protocol parameters of a deep space communication network according to claim 1, wherein the step s 1) specifically comprises:
the number of passes k experienced when only one block is passed on the ith hop is calculated according to min_i ：
Wherein p is seg_i Representing segment loss probability on the ith hop, N R Representing the number of red data segments contained in a block, m representing all theoretically possible transfer rounds;
the number of passes k experienced when passing the entire file is calculated according to max_i ：
Where f represents the red data duty ratio, N, in a single block to be transmitted bundle Representing a dimension L file Is divided into N bundle Multiple bundles transmit, L bundle_head Representing the length of the header of bundle, L block Representing the size of an individual block, L seg_payload_i Representing the load size of a single segment on the ith hop.
3. The method for optimizing configuration of LTP protocol parameters of deep space communication network according to claim 2, wherein the step s 3) specifically comprises:
the T of the previous (q-1) hop is obtained according to the following formula former ：
Wherein T is trans_a_mean 、T prop_a_mean And T ex_time_a_mean Respectively represent block q_final Average transmission time, average propagation time and average additional transfer time at hop a, T former_a Representing block q_final Average transfer total delay of transmission on the a-th hop, a e [1, q]；
The maximum total transmission time delay T of a single block in the q-th transmission is obtained according to the following method block_q_final ：
T block_q_final ＝T prop_q_final +T trans_q_final +T ex_time_q
Wherein T is prop_q_final 、T trans_q_final And T ex_time_q_final Respectively represent block q_final Propagation time, transmission time and additional delivery time at the q-th hop;
t of the post (n-q) jump is obtained according to the following formula latter ：
Wherein T is later_a The time interval from the time when the last block on the (a-1) hop finishes transmitting to the time when the last block on the a hop finishes transmitting is shown, and n shows the total number of hops through which data is transmitted from a source end to a destination end.
4. The method for optimizing configuration of LTP protocol parameters of deep space communication network according to claim 3, wherein the step t 1) specifically comprises:
setting segment frame size L on each segment link seg_frame_a For setting value, the head length L of the combined segment seg_header Obtaining the load L of segment on each link according to the following formula seg_payload_a Thereby completing the initialization of segment:
L seg_payload_a ＝L seg_frame_a -L seg_header
will L seg_payload_a Give L seg_payload 、L seg_frame_a Give L seg_frame Substituting the block size L block Is the minimum value L of (2) b_min Thus completing the initialization of the block;
wherein L is RS_frame Representing RSFrame size, L seg_payload Representing the load size, L, of segments seg_frame Representing the frame size of segments, R data Representing the data transmission rate of the data channel, R ACK Indicating the data transmission rate of the ACK channel.
5. The method for optimizing configuration of LTP protocol parameters of deep space communication network according to claim 4, wherein the step t 2) specifically comprises:
with L b_min For block size, substituting to find T former_a 、T block_q_final And T latter_a Will calculate the T file_multihop The problem of minimum segment size translates to T former_a (L seg_payload_a )、T block_q_final (L seg_payload_q ) And T latter_a (L seg_payload_a ) The problem of convex optimization of the function is solved, and the local optimal L meeting the first-order requirement of KKT on each section of link is obtained seg_payload_a *，L seg_payload_a * A local optimal solution for segment; wherein L is seg_payload_q Representing segment load size on the q-th hop;
will L seg_payload_a * Give L seg_payload Substituting the block size L of each section of link into the following formula to obtain the block size L of each section of link block Is the minimum value L of (2) b_min_a ：
L from each segment of link b_min_a The maximum value is given to L b_min ，L b_min Is the locally optimal solution of block.
6. The method for optimizing configuration of LTP protocol parameters of a deep space communication network according to claim 5, wherein the step t 5) specifically comprises:
according to the following formula, the actual aggregate size L of the block in the data transmission process block_act Obtaining the optimal design value N of session sess_opt ：
N sess_opt ＝1.2×(L file /L block_act )。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210409917.1A CN114679385B (en) | 2022-04-19 | 2022-04-19 | LTP protocol parameter optimization configuration method for deep space communication network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210409917.1A CN114679385B (en) | 2022-04-19 | 2022-04-19 | LTP protocol parameter optimization configuration method for deep space communication network |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114679385A CN114679385A (en) | 2022-06-28 |
| CN114679385B true CN114679385B (en) | 2023-11-14 |
Family
ID=82078083
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210409917.1A Active CN114679385B (en) | 2022-04-19 | 2022-04-19 | LTP protocol parameter optimization configuration method for deep space communication network |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114679385B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103095438A (en) * | 2013-01-09 | 2013-05-08 | 哈尔滨工业大学深圳研究生院 | Deep space delay tolerant network (DTN) multiple hop transmission method |
| CN103401778A (en) * | 2013-08-26 | 2013-11-20 | 西安电子科技大学 | Receiving-end buffer overflow probability guarantee based multi-path transmission packet scheduling method |
| US8954207B1 (en) * | 2013-09-06 | 2015-02-10 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Method of enhancing on-board state estimation using communication signals |
| CN104486043A (en) * | 2014-12-29 | 2015-04-01 | 中山大学 | Self-adaptive cooperative network coding method for differentiated services |
| CN104683065A (en) * | 2015-02-02 | 2015-06-03 | 哈尔滨工业大学深圳研究生院 | Deep-space-communication-oriented cross-layer joint file transmission method and system |
| CN104836642A (en) * | 2015-04-20 | 2015-08-12 | 哈尔滨工业大学深圳研究生院 | LTP (Licklider Transmission Protocol) optimized design method based on erase code |
| CN105227457A (en) * | 2015-10-28 | 2016-01-06 | 哈尔滨工业大学深圳研究生院 | Towards the protocol Data Unit cross-layer optimizing method under DTN dynamic link |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8014336B2 (en) * | 2006-12-18 | 2011-09-06 | Nokia Corporation | Delay constrained use of automatic repeat request for multi-hop communication systems |
| US8719199B2 (en) * | 2011-09-21 | 2014-05-06 | Brain Corporation | Systems and methods for providing a neural network having an elementary network description for efficient implementation of event-triggered plasticity rules |
| US9830920B2 (en) * | 2012-08-19 | 2017-11-28 | The Regents Of The University Of California | Method and apparatus for polyphonic audio signal prediction in coding and networking systems |
-
2022
- 2022-04-19 CN CN202210409917.1A patent/CN114679385B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103095438A (en) * | 2013-01-09 | 2013-05-08 | 哈尔滨工业大学深圳研究生院 | Deep space delay tolerant network (DTN) multiple hop transmission method |
| CN103401778A (en) * | 2013-08-26 | 2013-11-20 | 西安电子科技大学 | Receiving-end buffer overflow probability guarantee based multi-path transmission packet scheduling method |
| US8954207B1 (en) * | 2013-09-06 | 2015-02-10 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Method of enhancing on-board state estimation using communication signals |
| CN104486043A (en) * | 2014-12-29 | 2015-04-01 | 中山大学 | Self-adaptive cooperative network coding method for differentiated services |
| CN104683065A (en) * | 2015-02-02 | 2015-06-03 | 哈尔滨工业大学深圳研究生院 | Deep-space-communication-oriented cross-layer joint file transmission method and system |
| CN104836642A (en) * | 2015-04-20 | 2015-08-12 | 哈尔滨工业大学深圳研究生院 | LTP (Licklider Transmission Protocol) optimized design method based on erase code |
| CN105227457A (en) * | 2015-10-28 | 2016-01-06 | 哈尔滨工业大学深圳研究生院 | Towards the protocol Data Unit cross-layer optimizing method under DTN dynamic link |
Non-Patent Citations (3)
| Title |
|---|
| Haitao Wu,Yunhe Li.LTP asynchronous accelerated retransmission strategy for deep space communications.2016 IEEE International Conference on Wireless for Space and Extreme Environments.2017,全文. * |
| 深空通信LTP传递时延的理论建模及试验验证;王洋，杨宏;系统仿真学报;第29卷(第3期);全文 * |
| 面向空间差错信道的LTP协议优化;海洁;中国优秀硕士学位论文数据库;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114679385A (en) | 2022-06-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Cui et al. | Energy efficient opportunistic network coding for wireless networks | |
| US9288719B2 (en) | Link adaptation for a multi-hop route in a wireless mesh network | |
| US8363634B2 (en) | Wireless communication method, wireless communication apparatus and access point apparatus | |
| KR102139721B1 (en) | Apparatus and method for nested network cording for multipath protocol | |
| US20140112352A1 (en) | Self-adaptive Network Control Transmission Method and System Based on TCP | |
| JP5575236B2 (en) | Wireless communication system and terminal device | |
| CN107210908A (en) | Method and system for the rate adaptation of data traffic | |
| CN113114415B (en) | Density selection method based on adjustable sparse network coding | |
| CN108632911B (en) | Self-adaptive collision avoidance real-time medium access control method based on global scheduling | |
| CN113141207B (en) | Time-sensitive service-oriented spatial information network data transmission method | |
| CN114679385B (en) | LTP protocol parameter optimization configuration method for deep space communication network | |
| CN110086870A (en) | The parallel method for reliable transmission of the multipath of data-oriented central site network | |
| CN105227457B (en) | Towards the protocol Data Unit cross-layer optimizing method under DTN dynamic links | |
| CN110537379A (en) | For carrying out the device and method of data transmission between base station in a wireless communication system | |
| CN114499777B (en) | Data transmission method for cluster unmanned system | |
| WO2015088018A1 (en) | Multi-hop wireless device and multi-hop wireless system | |
| CN112672432B (en) | Flexible high-efficiency multiple access protocol design method for unmanned platform networking | |
| US20050232152A1 (en) | Method and system for pre-fetching network data using a pre-fetching control protocol | |
| Akshay et al. | Bandwidth optimized multicast routing algorithm based on hybrid mesh and tree structure with collision control in MANET using lempel-ziv-oberhumer method | |
| CN110381561B (en) | Safe transmission method based on energy efficiency in cache-assisted multi-relay transmission system | |
| CA2672416C (en) | System and method for relaying turbo-coded piggyback messages | |
| CN104704760B (en) | The method and device of multiple source dynamic network coding | |
| CN113395720B (en) | Relay node guided multi-hop mobile ad hoc network MAC layer communication method | |
| CN106330399A (en) | Rapid feedback method applicable to network coding of multihop heterogeneous network | |
| CN111740905B (en) | Routing method for realizing reliable communication link under wireless ad hoc network environment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |