CN113613308B - Flexible frame structure coding time slot ALOHA data transmission method and device - Google Patents
Flexible frame structure coding time slot ALOHA data transmission method and device Download PDFInfo
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Abstract
One or more embodiments of the present disclosure provide a flexible frame structure coding timeslot ALOHA data transmission method and apparatus, including determining a target access node and a distance to the target access node according to received signal strength of surrounding access nodes, estimating a number of user terminals accessing the target access node according to the distance to the target access node and an intercepted number of user terminals accessing the target access node, determining an access probability according to a set number of timeslots, a data amount of the user terminals, and the number of the user terminals accessing the target access node, and transmitting data according to the access probability. The embodiment can determine the access probability according to the number of the accessed user sides, flexibly adjust the access strategy, improve the resource utilization rate and the communication performance, and simultaneously can be suitable for communication systems with no frame and frame structures.
Description
Technical Field
One or more embodiments of the present disclosure relate to the field of communications technologies, and in particular, to a flexible frame structure coded timeslot ALOHA data transmission method and apparatus.
Background
When a plurality of user ends access channels transmit data to the same receiving end, the time slot ALOHA scheme is used for reducing collision. Some time slot ALOHA methods are applicable to systems without frame structures, a user side divides data to be sent into a plurality of data blocks, the data blocks are sent in sequence, and after a receiving end successfully recovers one data block, the user side sends the next data block; the time slot ALOHA coding method is suitable for a system with a fixed frame structure, in one frame, a user terminal codes each data block into a pre-coding group by using an error correcting code, the pre-coding group is randomly distributed into a time slot in the one frame, and a receiving terminal receives a complete frame and then carries out continuous interference elimination and decoding to recover data. The above method cannot be compatible with a system having no frame structure and a fixed frame structure at the same time, and cannot adjust the access policy according to the number of the clients.
Disclosure of Invention
In view of this, one or more embodiments of the present disclosure provide a method and an apparatus for transmitting flexible frame structure coded timeslot ALOHA data, which are compatible with data transmission of systems without frame structure and with fixed frame structure, and can adjust an access policy according to the number of clients, thereby improving system performance and resource utilization.
In view of the above, one or more embodiments of the present specification provide a flexible frame structure coded slotted ALOHA data transmission method, including:
determining a target access node and a distance to the target access node according to the received signal strength of surrounding access nodes;
estimating the total number of the user terminals accessing the target access node in the communication coverage range of the target access node according to the distance and the number of the intercepted user terminals accessing the target access node;
determining access probability according to the set time slot number, the data amount of the user side and the total number of the user sides;
and transmitting data according to the access probability.
Optionally, the determining, according to the received signal strength of the surrounding access nodes, the target access node is: determining a target access node with the maximum signal intensity according to the received signal intensity of the surrounding access nodes;
the determining the distance to the target access node comprises:
calculating the signal energy ratio of the signal energy of the target access node to the signal energy of other access nodes;
determining the distance ratio of the distance to the target access node to the distance to other access nodes according to the signal energy ratio;
and calculating the distance to the target access node according to the distance ratio.
Optionally, estimating the total number of the user terminals accessing the target access node within the communication coverage of the target access node includes:
and estimating the total number of the user sides according to the number of the user sides which can be intercepted and are accessed to the target access node under the distance and a preset user side distribution rule.
Optionally, the determining, according to the set number of time slots, the data amount of the user side, and the total number of the user sides, the access probability is: and determining the optimal access probability based on a differential evolution algorithm according to the time slot number, the data volume of the user side and the total number of the user sides.
Optionally, determining the optimal access probability based on a differential evolution algorithm includes:
constructing a time slot sample set;
performing theoretical analysis on each time slot distribution sample in the time slot sample set to obtain corresponding error probability;
selecting the time slot distribution sample with the minimum error probability as an optimal time slot distribution sample;
mutating a predetermined number of new time slot distribution samples on the basis of the optimal time slot distribution samples, and constructing a new time slot sample set comprising the new time slot distribution samples;
determining the error probability of each new time slot distribution sample;
comparing the error probability of the optimal time slot distribution sample with the error probability of each new time slot distribution sample, and if the error probability of the optimal time slot distribution sample is smaller than that of the currently compared new time slot distribution sample, replacing the currently compared new time slot distribution sample with the optimal time slot distribution sample to obtain a new time slot sample set with optimal degree distribution;
and determining the optimal access probability according to the new time slot sample set with the optimal degree distribution.
Optionally, the sending data according to the access probability includes:
dividing original data to be sent into at least two data blocks with the same data quantity;
encoding all data blocks by using an error correcting code to obtain a pre-encoded packet;
and sending the pre-coded packet to a time slot according to the access probability.
The present specification also provides a flexible frame structure coded slotted ALOHA data transmission apparatus, comprising:
the distance determining module is used for determining a target access node and the distance to the target access node according to the received signal strength of the surrounding access nodes;
the estimation module is used for estimating the total number of the user terminals accessing the target access node in the communication coverage range of the target access node according to the distance and the number of the intercepted user terminals accessing the target access node;
the access probability calculation module is used for determining the access probability according to the set time slot number, the data amount of the user side and the total amount of the user side;
and the sending module is used for sending data according to the access probability.
Optionally, the distance determining module is configured to determine, according to the received signal strength of the surrounding access nodes, a target access node with the maximum signal strength; calculating the signal energy ratio of the signal energy of the target access node to the signal energy of other access nodes; determining the distance ratio of the distance to the target access node to the distance to other access nodes according to the signal energy ratio; and calculating the distance to the target access node according to the distance ratio.
Optionally, the estimating module is configured to estimate, according to the number of the user terminals that can be intercepted at the distance and access to the target access node, the total number of the user terminals according to a preset user terminal distribution rule.
Optionally, the access probability calculation module is configured to determine an optimal access probability based on a differential evolution algorithm according to the number of time slots, the data amount of the user side, and the total number of the user sides.
As can be seen from the foregoing, in the flexible frame structure coding slotted ALOHA data transmission method and apparatus provided in one or more embodiments of the present disclosure, a target access node and a distance to the target access node are determined according to received signal strengths of surrounding access nodes, the number of user terminals accessing the target access node is estimated according to the distance to the target access node and the number of intercepted user terminals accessing the target access node, an access probability is determined according to the number of slots, the number of data of the user terminals, and the number of user terminals accessing the target access node, and data is transmitted according to the access probability. By using the method of the embodiment, the access probability can be determined according to the number of the accessed user sides, the access strategy can be flexibly adjusted, the resource utilization rate and the communication performance can be improved, and meanwhile, the method can be suitable for communication systems with no frame and frame structures.
Drawings
In order to more clearly illustrate one or more embodiments or prior art solutions of the present specification, the drawings that are needed in the description of the embodiments or prior art will be briefly described below, it is obvious that the drawings in the description below are only one or more embodiments of the present specification, and that other drawings may be obtained by those skilled in the art without inventive effort.
FIG. 1 is a schematic flow diagram of a method according to one or more embodiments of the present disclosure;
fig. 2 is a schematic coverage area diagram of a ue and an access node according to one or more embodiments of the present disclosure;
fig. 3 is a schematic location diagram of a ue and an access node according to one or more embodiments of the present disclosure;
fig. 4 is a schematic diagram of coordinate system locations of a ue and an access node according to one or more embodiments of the present disclosure;
fig. 5 is a schematic diagram illustrating coverage areas of a ue and a target access node according to one or more embodiments of the present disclosure;
FIG. 6 is a flow diagram illustrating a method for determining access probability in accordance with one or more embodiments of the disclosure;
FIG. 7 is a schematic diagram of a bipartite structure according to one or more embodiments of the present disclosure;
FIG. 8 is a graphical representation of performance results of the method of the present description and prior methods;
FIG. 9 is a schematic diagram of an apparatus according to one or more embodiments of the present disclosure;
fig. 10 is a schematic structural diagram of an electronic device according to one or more embodiments of the present disclosure.
Detailed Description
For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.
It is to be understood that unless otherwise defined, technical or scientific terms used in one or more embodiments of the present disclosure should have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in one or more embodiments of the specification is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.
As described in the background art, in a slotted ALOHA communication system without a frame structure, a plurality of clients simultaneously transmit data to a receiving end according to a uniform time slot, assuming that the data amount transmitted by each client is the same, the client first divides the original data to be transmitted into a plurality of data blocks with the same data amount, transmits one data block in the time slot, and after the receiving end correctly recovers the currently transmitted data block, notifies the client, and the client transmits the next data block until all data blocks are transmitted. In a Coded Slotted ALOHA (CSA) communication system with a frame structure, each frame is composed of a plurality of time slots, a user end divides original data into a plurality of data blocks with the same data quantity, randomly selects an error correction code from a coding set, codes the data blocks to obtain a plurality of pre-coding groups, randomly distributes the pre-coding groups into the time slots in one frame, and a receiving end starts to eliminate continuous interference after receiving a complete frame, recovers the pre-coding groups and decodes the pre-coding groups to obtain the original data.
In the process of implementing the present disclosure, the applicant finds that the current slotted ALOHA method is suitable for a system without a frame structure or with a fixed frame structure, but cannot be compatible with the system without the frame structure and the system with the fixed frame structure; moreover, when the number of the ue is increased or decreased, the access policy cannot be flexibly adjusted according to the number of the ue.
In view of this, embodiments of the present disclosure provide a flexible frame structure coding timeslot ALOHA data transmission method, which is compatible with a communication system without a frame structure and a fixed frame structure, and can determine a corresponding access policy according to the number of clients, thereby improving communication performance and resource utilization.
Hereinafter, the technical means of the present disclosure will be described in further detail with reference to specific examples.
As shown in fig. 1, an embodiment of the present specification provides a flexible frame structure coded slotted ALOHA data transmission method, including:
s101: determining a target access node and a distance to the target access node according to the received signal strength of surrounding access nodes;
in the present embodiment, as shown in fig. 3, several access nodes are deployed in a communication network, each access node has its own communication coverage, and adjacent access nodes may have overlapping communication coverage. The user terminal receives the broadcast signals of the surrounding access nodes, if the signal transmitting power of each access node is the same, the distance between the user terminal and the access nodes is from far to near, and the signal intensity of the broadcast signals received by the user terminal is from strong to weak. Therefore, the user side receives the broadcast signals of all the surrounding access nodes, selects the access node with the maximum signal strength as the target access node according to the strength of the signal strength, and accesses the target access node to realize communication with the receiving end.
After the target access node is determined, the distance from the user side to the target access node is further determined according to the signal intensity of the target access node and the signal intensity of other access nodes.
In some methods, the communication network is not limited to network architectures such as a cellular network, an ad-hoc network (ad-hoc network), etc., base stations serving as access nodes are deployed at different geographic locations in the cellular network, and a user end located in the cellular network can access the base stations to communicate with a receiving end; high-level nodes serving as access nodes are deployed in the self-organizing network, and a user side located in the self-organizing network accesses the high-level nodes to communicate with a receiving end. The foregoing is merely exemplary and the types of communication networks and communication principles are not intended to be limiting and specified.
S102: estimating the total number of user ends accessing the target access node in the communication coverage range of the target access node according to the distance to the target access node and the number of the intercepted user ends accessing the target access node;
as shown in fig. 2 and 5, in the present embodiment, the ue can listen to the ue accessing the target access node and the number of ues using carrier sensing technology, and the listening range of the ue is divided according to the distance from the ue to the target access node and the number of ues that can listen at the distance, and the listening range of the ue is generally smaller than the communication coverage of the target access node.
If the user terminals are assumed to be distributed according to the predetermined distribution rule, the total number of the user terminals accessing the target access node within the communication coverage of the target access node can be estimated according to the number of the user terminals that the user terminals can monitor in the distance. Optionally, to facilitate analysis and calculation, the clients are uniformly distributed within the communication coverage range; or, according to parameters such as time periods or geographic markers, the user terminals are distributed in a specific manner, for example, in a peak time period, the user terminals are distributed densely, in a low peak time period, the user terminals are distributed sparsely, in a specific building area, the user terminals are distributed densely, in other areas, the user terminals are distributed sparsely, and the like; the above is merely an exemplary illustration, and the specific distribution rule of the ue is not specifically limited.
S103: determining access probability according to the set time slot number, the data volume of the user side and the total number of the user sides;
s104: and transmitting the data according to the access probability.
In this embodiment, after the total number of the user terminals accessing the target access node is determined, an optimal access probability is determined based on a differential evolution algorithm according to the set number of time slots (the number of time slots required to be occupied according to the data to be sent), the data amount of the data to be sent by the user terminals, and the estimated total number of the user terminals accessing the target access node, and the user terminals send the data according to the determined access probability.
The flexible frame structure coding timeslot ALOHA data transmission method provided by the embodiment comprises the steps of determining a target access node and the distance to the target access node according to the received signal intensity of surrounding access nodes, estimating the number of user terminals accessing the target access node according to the distance to the target access node and the number of intercepted user terminals accessing the target access node, determining the access probability according to the number of time slots, the data amount of the user terminals and the number of the intercepted user terminals accessing the target access node, and sending data according to the access probability. The data transmission method of the embodiment can determine the access probability according to the number of the accessed user sides, flexibly adjust the access strategy, improve the resource utilization rate and the communication performance, and meanwhile, can be suitable for a communication system without frames and with a frame structure.
In some embodiments, the target access node is determined to be, based on received signal strengths of surrounding access nodes: determining a target access node with the maximum signal strength according to the signal strength of the surrounding access nodes received by the user side;
determining a distance to a target access node, comprising:
calculating the signal energy ratio of the signal energy of the target access node to the signal energy of other access nodes;
determining the distance ratio of the distance to the target access node to the distance to other access nodes according to the signal energy ratio;
and calculating the distance to the target access node according to the distance ratio.
As shown in fig. 3, according to the deployment characteristics of the access nodes in the communication network, assuming that the deployment positions of the access nodes are regular triangles, and the same user side is within the communication coverage range of the access nodes around the user side, when the user side accesses the communication network, the user side receives the broadcast signals of the access nodes around the user side at the same time.
After the user side obtains the signal intensity of the target access node and the signal energy of other surrounding access nodes, the signal energy ratio of the signal energy of the target access node to the signal energy of the other access nodes is calculated; calculating the distance ratio of the distance from the user side to the target access node and the distance from the user side to other access nodes according to the signal energy ratio; and calculating the distance from the user side to the target access node according to the distance ratio. Specifically, the method comprises the following steps:
assuming that the number of the surrounding access nodes is three, and the three access nodes are deployed in a regular triangle position relationship, the distances from the user side to the three access nodes are d1、d2、d3The signal power of the ue receiving three access nodes is expressed as:
where P denotes that the three access nodes have the same transmit power, hi(t) represents the small-scale fading of the signal from the access node i at time t, and h is the Rayleigh model considering the small-scale fadingi(t) obeys an exponential distribution.
α is a large scale fading index for the distance to access node i.
The statistically accumulated signal energy, based on the received signal power model, is expressed as:
when the statistical signal time T is sufficiently long, it can be found that:
∫Th1(t)dt＝∫Th2(t)dt＝∫Th3(t)dt (3)
and then, the signal energy ratio between the target access node (set as the access node 1) and other access nodes is obtained, and is expressed as:
the distances d from the user end to the target access node can be respectively determined according to (4) and (5)1And the distance d between the user terminal and other access nodes2、d3The distance ratio of (c).
As shown in FIG. 4, based on the principle that all points having the same ratio of distances to two fixed points on a plane constitute a circle, the distance ratio d is used1/d2Construct a circle A according to the distance ratio d1/d3Construction of circle B, circle A andthe intersection point of the circle B can be determined as the location of the user terminal.
Based on the position relation between the user side and the surrounding access nodes, a connection line where the target access node and one of the access nodes are located is taken as an X axis, and a straight line passing through the middle point of the connection line and perpendicular to the X axis is taken as a Y axis, so that an XOY coordinate system is established. Let the coordinates of the target access node be (a,0), then the coordinates of one of the access nodes be (-a, 0).
Let k1＝d1/d2,(k1≤1)，k2＝d1/d3,(k2Less than or equal to 1), the center coordinates of the obtained circle A are as follows:
the radius of circle a is:
the center coordinates of the circle B are:
the radius of circle B is:
when d is1＝d2＝d3The coordinates of the user side are:
when d is1≠d2And d is1＝d3The coordinates of the user end may be:
the point coordinates shown in the formulas (11) and (12) are one inside the triangle and one outside the triangle, and the coordinates inside the triangle are selected as the coordinates of the user terminal.
When d is1＝d2And d is1≠d3The coordinates of the user end may be:
similarly, in the point coordinates shown in formulas (13) and (14), the coordinates inside the triangle are selected as the coordinates of the user side.
Setting:
when d is1≠d2、d1≠d3、d1,d2,d3Not equal to 0 and x1≠x2The method comprises the following steps:
1) if k is not equal to 0, k0And the coordinate of the user side can be more than or equal to 0:
2) if k is not equal to 0, k0<0, the coordinates of the user end may be:
3) if k is 0, the coordinates of the ue may be:
when d is1≠d2、d1≠d3、d1,d2,d3Not equal to 0 and x2＝x1In time, the coordinates of the user end may be:
wherein:
l3＝l2|k0| (29)
in the above two sets of coordinates of equations (17), (18), (19) and (20), (21) and (22), (23) and (24), the coordinate inside the triangle is selected as the coordinate of the user end.
The coordinates of the user end can be obtained through the calculation process, and the distance d from the user end to the target access node is determined according to the coordinates of the user end and the coordinates of the target access node1. The user end is positioned at a distance target access node d1The number of the user terminals accessing the target access node can be detected by carrier sensing (i.e. within the sensing range of the user terminal), and the number of the user terminals within the coverage of the target access node can be estimated by the number of the user terminals within the sensing range of the user terminals, assuming that the user terminals in the communication network are uniformly distributed. That is, knowing the interception range of the user end, the coverage range of the target access node, and the number of users accessing the target access node within the interception range of the user end, the number of users accessing the target access node within the coverage range of the target access node can be estimated.
In this embodiment, after the receiving end receives the data, it is considered that the data is first subjected to Successive Interference Cancellation (SIC), and the pre-coded packet is recovered, and then decoded to obtain the original data. Because the access probability directly influences the performance of continuous interference elimination, the user side selects the optimal access probability based on a differential evolution algorithm by taking the access probability as an optimization target, and transmits data by utilizing the optimal access probability to obtain the optimal communication performance.
As shown in fig. 7, the gaptor code-based slotted ALOHA communication system can be represented by a bipartite graph, and thus the performance of a precoded packet can be analyzed using density evolution.
Firstly, determining the time slot and the degree distribution of the pre-coding grouping according to the access strategy. The degree of a time slot can be viewed as the sum of M Bernoulli random variables, each with an access probability paccessTake 1 with probability 1-paccessTaking 0, and obtaining the time slot degree distribution as follows:
wherein D isBA probability mass function (probability mass function) representing a bernoulli random variable,
which represents a standard convolution of the signal with the signal,
represents DBSelf-convolved M times.
And then, obtaining the degree distribution of the pre-coding grouping according to the degree distribution of the time slot. Because each user terminal makes the number of times of sending the pre-coding packet as the same as possible, each pre-coding packet approaches to have the same degree, and the average degree of the pre-coding packet can be calculated according to the principle that the edges sent from two nodes in the bipartite graph are the same:
wherein D isS(x) Degree distribution polynomial representing time slot, x being the base of the polynomial, DS' (1) take derivative for degree distribution polynomial and let x equal to 1, N is time slot number, K is number of data blocks.
Further, the degree distribution of the precoded packets is represented as:
wherein
Respectively indicating a rounding-down and a rounding-up.
Defining a degree distribution (d) of slotsS(x) Edge distribution d of precoded packetsP(x) Expressed as:
wherein D isP(x) A degree distribution polynomial representing a pre-coded packet, x being the base of the polynomial.
Considering that the time slot passes through an erasure channel, the erasure probability is oa, and the error probability of the precoding packet is obtained by density evolution theoretical analysis:
xl＝dP(1-(1-ò)dS(1-xl-1)) (35)
wherein x islAfter the l iteration, the error probability of the pre-coded packet is shown, the probability of sending invalid information from the pre-coded packet is shown, and the probability is approximate to the probability that the pre-coded packet cannot be decoded.
Based on the above analysis, the optimal time slot degree distribution with the minimum error probability is selected
According to the formula (30), the optimal slot degree distribution is obtained
And deconvoluting to obtain the optimal access probability.
As shown in fig. 6, determining the optimal access probability based on the differential evolution algorithm according to the number of time slots, the data amount of the user terminal, and the total number of the user terminals includes:
s601: constructing a time slot sample set;
s602: carrying out theoretical analysis on each time slot distribution sample in the time slot sample set to obtain corresponding error probability;
s603: selecting a time slot distribution sample with the minimum error probability as an optimal time slot distribution sample;
s604: mutating a predetermined number of new time slot distribution samples on the basis of the optimal time slot distribution samples, and constructing a new time slot sample set comprising the new time slot distribution samples;
s605: determining the error probability of each new time slot distribution sample;
s606: comparing the error probability of the optimal time slot distribution sample with the error probability of each new time slot distribution sample, and if the error probability of the optimal time slot distribution sample is smaller than that of the currently compared new time slot distribution sample, replacing the currently compared new time slot distribution sample with the optimal time slot distribution sample to obtain a new time slot sample set with optimal degree distribution;
s607: and determining the optimal access probability according to the new time slot sample set with the optimal degree distribution.
In this embodiment, the optimal access probability is determined based on a differential evolution algorithm. Specifically, a set of slot samples including feasible slot distribution samples is first constructed. Randomly selecting some feasible time slot distribution samples, taking the time slot distribution samples as initial points, randomly walking by using a Queen's move method, when the walking time is long enough, considering that an approximately complete time slot distribution space is obtained, and selecting a preset number of time slot distribution samples from the time slot distribution space to form a time slot sample set. And then, theoretically analyzing the time slot distribution samples in the time slot sample set according to a formula (35) to obtain the error probability corresponding to each time slot distribution sample, and selecting the time slot distribution sample with the minimum error probability as the optimal time slot distribution sample after determining the error probabilities of all the time slot distribution samples. Based on the optimal time slot distribution sample, mutating a predetermined number of new time slot distribution samples, forming a new time slot sample set by the new time slot distribution samples, and theoretically analyzing each new time slot distribution sample in the new time slot sample set according to a formula (35) to obtain the error probability corresponding to each new time slot distribution sample; and comparing the error probability of the optimal time slot distribution sample with the error probability of each new time slot distribution sample, if the error probability of the optimal time slot distribution sample is smaller than the error probability of the currently compared new time slot distribution sample, replacing the currently compared new time slot distribution sample with the optimal time slot distribution sample, and according to the process, after all the new time slot distribution samples are processed, obtaining a new time slot sample set with optimal distribution. And (4) carrying out deconvolution according to the inverse operation of a formula (30) based on the new time slot sample set with the optimal degree distribution to obtain the optimal access probability.
In some embodiments, transmitting data according to the access probability comprises:
dividing original data to be transmitted into at least two data blocks with the same data quantity;
encoding all data blocks by using an error correcting code to obtain a pre-encoded packet;
and sending the pre-coded packet to the time slot according to the optimal access probability.
With reference to fig. 7, in the slotted ALOHA communication system shown in the bipartite graph, it is assumed that the ues 1 to M transmit raw data with equal data volume, each ue divides the raw data into K data blocks equally, encodes the K data blocks into P pre-encoded packets by using an error correction code (e.g., a parity code), and then transmits the P pre-encoded packets to the slot according to the determined optimal access probability, where each ue makes the number of times of transmission of each pre-encoded packet as same as possible, that is, the degree of pre-encoded packets is the same. In this embodiment, the determined optimal access probability is used to transmit data, which is applicable to both a system without a frame structure and a system with a fixed frame structure, and the optimal access probability is determined based on the number of the user terminals accessing the target access node to transmit data with the optimal access probability, so that system resources can be fully utilized, and communication performance can be improved.
The method of the present specification is described below by experimental data.
For the access probability, the number of user terminals M is set to 3, the number of partitioned data blocks K is set to 100, the precoding packet P is set to 110, and the number of time slots N is set to 1000, and the access probability P can be determined according to the above methodaccess0.9; otherwise, if N is set to 800, the access probability p can be determinedaccess0.8715; setting N to 1500, p may be determinedaccess0.93. Therefore, the access probability is insensitive to the influence of the time slot number, and the method of the embodiment can be suitable for a system with a fixed frame structure, a system with a variable frame structure and a system without the frame structure and has good applicability.
With reference to fig. 8, comparing the method of the present specification with the existing slotted ALOHA method, setting the number of the user terminals to be 20, the number of the data blocks to be 40, and the number of the pre-coding packets to be 50, experiments show that, in a scenario where the number of the user terminals is medium (the order of magnitude is 10^1), the method of the present specification adopts the optimal access probability to transmit data, which significantly improves the error performance compared with the existing method.
It should be noted that the method of one or more embodiments of the present disclosure may be executed by a single device, such as a computer or a server. The method of the embodiment can also be applied to a distributed scene and completed by the mutual cooperation of a plurality of devices. In such a distributed scenario, one of the multiple devices may perform only one or more steps of the method of one or more embodiments of the present description, and the multiple devices may interact with each other to complete the method.
It should be noted that the above description describes certain embodiments of this disclosure. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may also be possible or may be advantageous.
As shown in fig. 9, the present specification further provides a flexible frame structure coded slotted ALOHA data transmission apparatus, including:
the distance determining module is used for determining a target access node and the distance to the target access node according to the received signal strength of the surrounding access nodes;
the estimation module is used for estimating the total number of the user terminals accessing the target access node in the communication coverage range of the target access node according to the distance and the number of the intercepted user terminals accessing the target access node;
the access probability calculation module is used for determining the access probability according to the set time slot number, the data volume of the user side and the total number of the user sides;
and the sending module is used for sending the data according to the access probability.
For convenience of description, the above devices are described as being divided into various modules by functions, and are described separately. Of course, the functionality of the modules may be implemented in the same one or more software and/or hardware implementations in implementing one or more embodiments of the present description.
The apparatus in the foregoing embodiment is used for implementing the corresponding method in the foregoing embodiment, and has the beneficial effects of the corresponding method embodiment, which are not described herein again.
Fig. 10 is a schematic diagram illustrating a more specific hardware structure of an electronic device according to this embodiment, where the device may include: a processor 1010, a memory 1020, an input/output interface 1030, a communication interface 1040, and a bus 1050. Wherein the processor 1010, memory 1020, input/output interface 1030, and communication interface 1040 are communicatively coupled to each other within the device via bus 1050.
The processor 1010 may be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an Application Specific Integrated Circuit (ASIC), or one or more Integrated circuits, and is configured to execute related programs to implement the technical solutions provided in the embodiments of the present disclosure.
The Memory 1020 may be implemented in the form of a ROM (Read Only Memory), a RAM (Random Access Memory), a static Memory device, a dynamic Memory device, or the like. The memory 1020 may store an operating system and other application programs, and when the technical solution provided by the embodiments of the present specification is implemented by software or firmware, the relevant program codes are stored in the memory 1020 and called to be executed by the processor 1010.
The input/output interface 1030 is used for connecting an input/output module to input and output information. The i/o module may be configured as a component within the device (not shown) or may be external to the device to provide corresponding functionality. The input devices may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output devices may include a display, a speaker, a vibrator, an indicator light, etc.
The communication interface 1040 is used for connecting a communication module (not shown in the drawings) to implement communication interaction between the present device and other devices. The communication module can realize communication in a wired mode (for example, USB, network cable, etc.), and can also realize communication in a wireless mode (for example, mobile network, WIFI, bluetooth, etc.).
The bus 1050 includes a path to transfer information between various components of the device, such as the processor 1010, memory 1020, input/output interface 1030, and communication interface 1040.
It should be noted that although the above-mentioned device only shows the processor 1010, the memory 1020, the input/output interface 1030, the communication interface 1040 and the bus 1050, in a specific implementation, the device may also include other components necessary for normal operation. In addition, those skilled in the art will appreciate that the above-described apparatus may also include only the components necessary to implement the embodiments of the present disclosure, and need not include all of the components shown in the figures.
The electronic device of the foregoing embodiment is used for implementing the corresponding method in the foregoing embodiment, and has the beneficial effects of the corresponding method embodiment, which are not described again here.
Computer-readable media, including both permanent and non-permanent, removable and non-removable media, for storing information may be implemented in any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device.
Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, is limited to these examples; features from the above embodiments, or from different embodiments, may also be combined, steps may be implemented in any order, and there are many other variations of the different aspects of one or more embodiments of the present description, as described above, which are not provided in detail for the sake of brevity.
In addition, well-known power/ground connections to Integrated Circuit (IC) chips and other components may or may not be shown within the provided figures for simplicity of illustration and discussion, and so as not to obscure one or more embodiments of the description. Furthermore, devices may be shown in block diagram form in order to avoid obscuring the understanding of one or more embodiments of the present description, and this also takes into account the fact that specifics with respect to implementation of such block diagram devices are highly dependent upon the platform within which the one or more embodiments of the present description are to be implemented (i.e., specifics should be well within purview of one skilled in the art). Where specific details (e.g., circuits) are set forth in order to describe example embodiments of the disclosure, it should be apparent to one skilled in the art that one or more embodiments of the disclosure can be practiced without, or with variation of, these specific details. Accordingly, the description is to be regarded as illustrative instead of restrictive.
While the present disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art in light of the foregoing description. For example, other memory architectures (e.g., dynamic ram (dram)) may use the embodiments discussed.
It is intended that the one or more embodiments of the present specification embrace all such alternatives, modifications and variations as fall within the broad scope of the appended claims. Therefore, any omissions, modifications, substitutions, improvements, and the like that may be made without departing from the spirit and principles of one or more embodiments of the present disclosure are intended to be included within the scope of the present disclosure.
Claims (5)
1. A flexible frame structure coded slotted ALOHA data transmission method, comprising:
determining a target access node and a distance to the target access node according to the received signal strength of surrounding access nodes;
estimating the total number of the user terminals accessing the target access node in the communication coverage range of the target access node according to the distance and the number of the intercepted user terminals accessing the target access node and a preset user terminal distribution rule;
determining access probability based on a differential evolution algorithm according to the set time slot number, the data amount of the user side and the total number of the user sides, wherein the method comprises the following steps:
constructing a time slot sample set;
performing theoretical analysis on each time slot distribution sample in the time slot sample set to obtain corresponding error probability;
selecting the time slot distribution sample with the minimum error probability as an optimal time slot distribution sample;
mutating a predetermined number of new time slot distribution samples on the basis of the optimal time slot distribution samples, and constructing a new time slot sample set comprising the new time slot distribution samples;
determining the error probability of each new time slot distribution sample;
comparing the error probability of the optimal time slot distribution sample with the error probability of each new time slot distribution sample, and if the error probability of the optimal time slot distribution sample is smaller than that of the currently compared new time slot distribution sample, replacing the currently compared new time slot distribution sample with the optimal time slot distribution sample to obtain a new time slot sample set with optimal degree distribution;
determining the optimal access probability according to the new time slot sample set with the optimal degree distribution;
and transmitting data according to the access probability.
2. The method of claim 1, wherein determining the target access node based on the received signal strengths of the surrounding access nodes is: determining a target access node with the maximum signal intensity according to the received signal intensity of the surrounding access nodes;
the determining the distance to the target access node comprises:
calculating the signal energy ratio of the signal energy of the target access node to the signal energy of other access nodes;
determining the distance ratio of the distance to the target access node to the distance to other access nodes according to the signal energy ratio;
and calculating the distance to the target access node according to the distance ratio.
3. The method of claim 1, wherein transmitting data according to the access probability comprises:
dividing original data to be transmitted into at least two data blocks with the same data quantity;
encoding all data blocks by using an error correcting code to obtain a pre-encoded packet;
and sending the pre-coded packet to a time slot according to the access probability.
4. A flexible frame structure coded slotted ALOHA data transmission apparatus, comprising:
the distance determining module is used for determining a target access node and the distance to the target access node according to the received signal strength of the surrounding access nodes;
the estimation module is used for estimating the total number of the user terminals accessing the target access node in the communication coverage range of the target access node according to the distance and the number of the intercepted user terminals accessing the target access node and a preset user terminal distribution rule;
the access probability calculation module is used for determining the optimal access probability based on a differential evolution algorithm according to the set time slot number, the data quantity of the user side and the total quantity of the user side, and comprises the steps of;
constructing a time slot sample set;
performing theoretical analysis on each time slot distribution sample in the time slot sample set to obtain corresponding error probability;
selecting the time slot distribution sample with the minimum error probability as an optimal time slot distribution sample;
mutating a predetermined number of new time slot distribution samples on the basis of the optimal time slot distribution samples, and constructing a new time slot sample set comprising the new time slot distribution samples;
determining the error probability of each new time slot distribution sample;
comparing the error probability of the optimal time slot distribution sample with the error probability of each new time slot distribution sample, and if the error probability of the optimal time slot distribution sample is smaller than that of the currently compared new time slot distribution sample, replacing the currently compared new time slot distribution sample with the optimal time slot distribution sample to obtain a new time slot sample set with optimal distribution;
and the sending module is used for sending data according to the access probability.
5. The apparatus of claim 4,
the distance determining module is used for determining a target access node with the maximum signal intensity according to the received signal intensity of the surrounding access nodes; calculating the signal energy ratio of the signal energy of the target access node to the signal energy of other access nodes; determining the distance ratio of the distance to the target access node to the distance to other access nodes according to the signal energy ratio; and calculating the distance to the target access node according to the distance ratio.
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