An efficient frame aggregation relay method that meets the timeliness constraints of IoT information

Abstract

The present invention provides an efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information, including: obtaining the original data packet update frequency, the current relay frame aggregation period, the frame aggregation strategy, and the signal-to-noise ratio of a data center receiver; determining the average information age of frame aggregation of multiple Internet of Things sensor original data packets based on the original data packet update frequency and the current relay frame aggregation period; determining the average transmission efficiency of the frame aggregation strategy under a retransmission mechanism based on the frame aggregation strategy, the signal-to-noise ratio of the data center receiver, the data packet update frequency, and the current relay frame aggregation period; and optimizing and solving with the goal of maximizing the average transmission efficiency and the condition that the average information age meets a maximum limit to obtain an optimal solution for the relay frame aggregation period. By implementing the present invention to solve an analyzable approximate expression for the average transmission efficiency, the frame aggregation period is optimized, thereby achieving the purpose of improving transmission efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless relay transmission, and in particular relates to an efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information. Background Art

[0002] The Internet of Things (IoT) has seen significant growth in 5G and 6G mobile communications. However, the remote deployment and limited power consumption of numerous sensor devices make it difficult to transmit information to data centers. This is typically achieved through relaying. In the IoT, relay technology is used to enhance signals and expand coverage. Relay nodes collect signal energy from source nodes and use this energy for information transmission and energy distribution.

[0003] In the related art, a decoding and forwarding method is generally adopted on the relay auxiliary device, that is, the relay auxiliary device decodes the received signal, and then re-encodes the decoded information and forwards it to the destination node. The transmission efficiency of the above method is low. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide an efficient frame aggregation relay method and device that meets the timeliness constraints of Internet of Things information, so as to meet the demand for improving transmission efficiency.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] According to a first aspect, the present invention provides an efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information, including: obtaining the original data packet update frequency, the current relay frame aggregation period, the frame aggregation strategy and the signal-to-noise ratio of the data center receiver; determining the average information age of frame aggregation of multiple Internet of Things sensor original data packets based on the original data packet update frequency and the current relay frame aggregation period; determining the average transmission efficiency of the frame aggregation strategy under the retransmission mechanism based on the frame aggregation strategy, the signal-to-noise ratio of the data center receiver, the data packet update frequency and the current relay frame aggregation period; optimizing and solving with the goal of maximizing the average transmission efficiency and the condition that the average information age meets the maximum value limit to obtain the optimal solution for the relay frame aggregation period.

[0007] Optionally, the average transmission efficiency of the frame aggregation strategy under the retransmission mechanism is determined based on the frame aggregation strategy, the signal-to-noise ratio of the data center receiver, the data packet update frequency, and the current relay frame aggregation period, including: determining the original relay transmission efficiency based on the frame aggregation strategy; determining the bit error rate of the data center based on the signal-to-noise ratio of the data center receiver; determining the retransmission probability under the retransmission mechanism based on the bit error rate of the data center and the length of the message in the data packet; determining the probability of the data packet being aggregated within the aggregation period based on the time interval distribution parameters of the sensor-generated data packets; determining the average transmission efficiency of the frame aggregation strategy under the retransmission mechanism based on the original relay transmission efficiency, the retransmission probability under the retransmission mechanism, and the probability of the data packet being aggregated within the aggregation period.

[0008] Optionally, determining a retransmission probability under a retransmission mechanism based on a bit error rate of a data center and a length of a message in a data packet includes:

[0009] ;

[0010] in, Indicates Under the condition of , the probability of retransmission number is j-1, is the number of transmissions of the nth aggregate packet, , is the bit error rate of the data center, is the signal-to-noise ratio of the receiver, is the Q function, is the length of the message in the packet.

[0011] Optionally, determining the probability of the data packets being aggregated within the aggregation period based on the time interval distribution parameters of the data packets generated by the sensor includes: determining, based on the time interval distribution parameters of the data packets generated by the sensor, the probability of each data packet being aggregated within the aggregation period and the probability of at least one data packet being sent from the sensor to the relay auxiliary device within the aggregation period, using the following formula:

[0012] ;

[0013] ;

[0014] in, It represents the probability of the i-th data packet being aggregated within the aggregation period. The time interval of the sensor generating data packets follows the parameter The independent exponential distribution of K is the number of sensors served by a relay auxiliary device, so in the aggregation period The number of packets aggregated in follows the parameter Poisson distribution, Indicates that during the aggregation cycle The probability that at least one data packet is sent from the sensor to the relay auxiliary device within the aggregation period; the probability that the data packets are aggregated within the aggregation period is determined based on the probability that each data packet is aggregated within the aggregation period and the probability that at least one data packet is sent from the sensor to the relay auxiliary device within the aggregation period. The formula is as follows:

[0015] ;

[0016] in, It represents the probability that i packets are aggregated within the aggregation period.

[0017] Optionally, determining an average transmission efficiency of a frame aggregation strategy under the retransmission mechanism based on the relay transmission efficiency, the retransmission probability under the retransmission mechanism, and the probability of data packets being aggregated within an aggregation period includes:

[0018] ;

[0019] in, represents the average transmission efficiency of the frame aggregation strategy under the retransmission mechanism, 、 and Represents the frame header, message and frame trailer of the data packet respectively.

[0020] Optionally, based on the original data packet update frequency and the current relay frame aggregation period, the average information age of multiple IoT sensor original data packets for frame aggregation is determined, including: determining the expected time interval between the transmission completion of two adjacent target aggregation packets and the expected square of the time interval between the transmission completion of two adjacent target aggregation packets based on the original data packet update frequency and the current relay frame aggregation period, where the target aggregation packet is an aggregation packet containing the original data packet of the same IoT sensor; determining the expected interval between the transmission completion time and the generation time of the original data packet based on the original data packet update frequency and the current relay frame aggregation period; determining the average information age of multiple IoT sensor original data packets for frame aggregation based on the expected interval between the transmission completion times of two adjacent target aggregation packets, the expected square of the time interval between the transmission completion of two adjacent target aggregation packets, and the expected interval between the transmission completion time and the generation time of the original data packet.

[0021] Optionally, determining, based on the original data packet update frequency and the current relay frame aggregation period, an expected time interval between two adjacent target aggregation packet transmission completions and an expected time interval squared between two adjacent target aggregation packet transmission completions includes:

[0022] ;

[0023] ;

[0024] in, Indicates the expected time interval between the transmission completion of two adjacent target aggregation packets. It represents the expected square of the time interval between the transmission completion of two adjacent target aggregation packets. represents the aggregation period, Indicates the original data packet update frequency;

[0025] Based on the original data packet update frequency and the current relay frame aggregation period, determine the expected interval between the original data packet transmission completion time and the generation time, including:

[0026] ;

[0027] in, Indicates the expected interval between the transmission completion time and the generation time of the original data packet.

[0028] Optionally, determining an average information age for frame aggregation of multiple IoT sensor original data packets based on an expected interval between transmission completion times of two adjacent target aggregation packets, an expected square of a time interval between transmission completion times of two adjacent target aggregation packets, and an expected interval between transmission completion times and generation times of the original data packets includes:

[0029] ;

[0030] in, Represents the average information age.

[0031] Optionally, an optimization solution is performed with the goal of maximizing the average transmission efficiency and the condition that the average information age satisfies a maximum limit, to obtain an optimal solution for the relay frame aggregation period, including: analyzing the average transmission efficiency and determining a lower bound of the average transmission efficiency;

[0032] The lower bound of the average transmission efficiency is:

[0033] ;

[0034] in, express , express ;

[0035] The goal is to maximize the lower bound of the average transmission efficiency, and the average information age satisfies the maximum limit as a condition, including:

[0036] ;

[0037] ;

[0038] in, Indicates the maximum average information age.

[0039] Embodiments of the present invention provide an efficient frame aggregation and relay method that meets information timeliness constraints in the Internet of Things (IoT). This method uses the average age of information (AoI) as a metric for system performance and frame aggregation. An optimization problem is constructed using an approximate expression for the average AoI at the sensor and the average relay transmission efficiency, while also accounting for decoding errors and retransmissions. By solving this optimization problem—that is, finding an analyzable approximate expression for the average transmission efficiency—the frame aggregation period is optimized, thereby achieving improved transmission efficiency. Compared to traditional decode-and-forward methods, the proposed method significantly improves transmission efficiency.

[0040] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to make the purpose, technical solutions and beneficial effects of the present invention more clear, the present invention provides the following drawings for illustration:

[0042] Figure 1 This is a specific example flow chart of an efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information in the present invention;

[0043] Figure 2 A frame aggregation system model for a relay-assisted IoT network to which the method of the present invention is applied;

[0044] Figure 3 The sensor of the present invention AoI model;

[0045] Figure 4 The sensor of the present invention Frame aggregation AoI model;

[0046] Figure 5 The time interval between the transmission completion of two adjacent target aggregation packets in the present invention Schematic diagram of;

[0047] Figure 6 The sensor of the present invention The interval between the transmission completion time and the generation time of the original data packet Schematic diagram of;

[0048] Figure 7 This is a simulation diagram of the transmission efficiency of the method proposed in the present invention under different AoI thresholds;

[0049] Figure 8 This is a principle block diagram of a specific example of an electronic device in an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0051] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components; wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0052] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0053] The embodiment of the present invention provides an efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information, such as Figure 1 As shown, including:

[0054] S101, obtaining the original data packet update frequency, the current relay frame aggregation period, the frame aggregation strategy, and the signal-to-noise ratio of the data center receiver;

[0055] S102, determining an average information age of frame aggregation of multiple IoT sensor original data packets based on an original data packet update frequency and a current relay frame aggregation period;

[0056] S103, determining an average transmission efficiency of the frame aggregation strategy under the retransmission mechanism based on the frame aggregation strategy, the signal-to-noise ratio of the data center receiver, the data packet update frequency, and the current relay frame aggregation period;

[0057] S104 , optimizing and solving with the goal of maximizing the average transmission efficiency and the condition that the average information age satisfies the maximum limit, to obtain the optimal solution for the relay frame aggregation period.

[0058] For example, this embodiment establishes an IoT network in which a large number of sensors are deployed in remote areas to monitor environmental information. Given the limited transmission power of sensors, it is difficult for them to accurately transmit information to remote data centers. Therefore, multiple wireless relay auxiliary devices are deployed near the sensors to collect and forward sensor information within their coverage area. Assume that each relay auxiliary device is The sensor provides the service, For each sensor express.

[0059] During the environmental monitoring period, each sensor will randomly generate and upload its sensor data. Without loss of generality, in this embodiment, it is assumed that the time interval for generating sensor data on the sensor follows the parameter The exponential distribution has a probability density function (PDF) of:

[0060] ; (1.1)

[0061] Since the amount of information from sensors is relatively small, short data packets are usually used for sensing data transmission in IoT networks. This paper assumes that each sensing data packet consists of three parts: frame header, message and frame trailer, and their lengths can be expressed as 、 and Indicates. And there is .

[0062] It is easy to see that the required information only accounts for a small part of the sensor data packet overhead, while the frame header and trailer that do not carry information account for the majority of the overhead. In order to avoid the waste of energy resources caused by frequent forwarding of sensor information, this embodiment uses frame aggregation technology at the relay auxiliary device. Figure 2 The relay-assisted device-assisted frame aggregation system model of IoT network shown in the figure is used to aggregate the frames of the IoT network. Transmit data to the data center. During this interval, all data packets received by the relay auxiliary device will be aggregated into a large data frame with a common header and tail to improve the transmission efficiency of the required information.

[0063] Will Defined as the relay auxiliary equipment in the time interval The transmission efficiency of the frame aggregation strategy can be calculated as follows:

[0064] ; (1.2)

[0065] Clearly, when considering only transmission efficiency and ignoring the retransmission overhead caused by transmission failures, aggregating more packets results in higher transmission gains. However, long wait times for aggregation increase system latency. Furthermore, excessively long frame lengths increase the likelihood of transmission failures, necessitating numerous retransmissions, which can incur even greater resource overhead. Therefore, it's important to consider both latency and retransmission considerations when designing aggregation schemes.

[0066] Therefore, this embodiment proposes an efficient frame aggregation and relay method that satisfies IoT information timeliness constraints by analyzing the average information age and average transmission efficiency of IoT networks. The following describes the derivation of the average information age and average transmission efficiency.

[0067] Regarding step S102, the calculation formula for the average information age is derived as follows:

[0068] In IoT networks, it's important to consider changes in sensor states captured by the data center, rather than focusing solely on the end-to-end latency from the sensor to the data center. Therefore, the concept of Age of Information (AoI) can be used as a latency metric in this embodiment, accurately reflecting the freshness of sensor states in the data center. Slow sensor state updates, long data transmission times, and significant processing delays are the primary factors contributing to an increased AoI in the system. Therefore, AoI represents a comprehensive consideration of sensor data latency.

[0069] like Figure 3 As shown, when only AoI is considered, the sensor The AoI can be defined as:

[0070] ; (1.3)

[0071] in, is the current time, is the index of the latest received data packet, is the timestamp of the data packet. Assume that the relay auxiliary device sends The timestamp of the data packet when it is delivered to the data center is It can be seen that in IoT networks without frame aggregation, AoI is It increases linearly until the latest data packet arrives at the data center, where it decreases.

[0072] Generally speaking, the duration is Internal Observation , we can get its average AoI as:

[0073] ; (1.4)

[0074] Here, we assume that the random process Is ergodic. Without loss of generality, the observation time Set to the last packet The transfer completion time is , by setting the observation window length to infinity, we can calculate The average AoI is:

[0075] ; (1.5)

[0076] Unlike traditional IoT, when this embodiment uses a frame aggregation solution, the data packet is not forwarded immediately after arriving at the relay auxiliary device. Instead, it needs to wait for a period of time until the aggregation time ends. Frame aggregation AoI such as Figure 4 As shown, Figure 3 The difference is that Figure 4 middle Indicates the timestamp when the relay auxiliary device completes aggregation and forwards the aggregated data packet to the data center. In addition, if If a new packet arrives at the relay auxiliary device, but the old packet has not yet been sent (frame aggregation is not completed), the old packet will not affect the AoI (node ​​without timestamp). It is worth noting that since the waiting time for frame aggregation is usually much larger than the data processing time of the relay auxiliary device and the data center, this embodiment ignores the processing time in the proposed scheme.

[0077] The average AoI in this embodiment can also be obtained using the geometric method, similar to the calculation method of the average AoI in traditional IoT. Figure 4 As shown, in formula (1.5) The integral can be obtained from a single polygon The area of ​​multiple isosceles trapezoids The area of ​​a single isosceles triangle Summing the areas of we get:

[0078] ; (1.6)

[0079] Obviously, when Sometimes and , then formula (1.5) can be written as:

[0080] ; (1.7)

[0081] exist Figure 4 In the Contains The aggregated packet of the original data packet and the Contains The transmission completion time between the aggregated packets of the original data packets is expressed as In addition, the influence of the average AoI The time it takes to complete the transmission of the original data packet and generation time The interval between is defined as Then, the first term of Equation (1.7) can be expressed as:

[0082] ; (1.8)

[0083] Based on the original data packet update frequency and the current relay frame aggregation period, the expected time interval between the transmission completion of two adjacent target aggregation packets is determined. The specific calculation method is:

[0084] Lemma 1: When the raw data packet update frequency of any sensor is And the aggregation period of the relay is When the expected time interval between the transmission completion of two adjacent target aggregation packets is can be calculated as:

[0085] ; (1.9)

[0086] prove:

[0087] like Figure 5 Given the The specific representation of Contains ( ) aggregation cycles , and in the initial No original data packets are received from When ( ) package in the first When generated in an aggregation cycle, the initial The package will not affect Average period. Average AoI Will be the first Data package updates. Then there are:

[0088] ; (1.10)

[0089] in is a random variable, is a constant. Therefore, the above formula can be further written as:

[0090] ; (1.11)

[0091] according to , we can get the expectation for:

[0092] ; (1.12)

[0093] in It's an event The probability of . Expressed as exist An event that does not generate any data packets within consecutive aggregation periods will be Expressed as In the subsequent generated within aggregation cycles If we look at the events of a data packet, we can get:

[0094] ; (1.13)

[0095] Then, In time interval The number of raw data packets generated within is defined as ,but A The probability can be used As mentioned above, the raw data packet generation interval of any sensor follows an exponential distribution, so in time The data packets generated during this period also follow the Poisson distribution, that is:

[0096] ; (1.14)

[0097] From this, we can get A The probability is:

[0098] ; (1.15)

[0099] Likewise, B The probability can be expressed as:

[0100] ; (1.16)

[0101] According to the previous analysis, we can get:

[0102] ; (1.17)

[0103] Substituting equations (1.15) and (1.17) into equation (1.13), we can obtain:

[0104] ; (1.18)

[0105] Substituting the above formula into formula (1.10), we can calculate:

[0106] ; (1.19)

[0107] It is easy to calculate that and .therefore, This is Equation (1.9). The proof is complete.

[0108] The second term of formula (1.7) can be further expressed as:

[0109] ; (1.20)

[0110] from Figure 4 It can be seen in the Isosceles trapezoid It can be calculated by subtracting the areas of the two isosceles triangles, that is:

[0111] (1.21)

[0112] Substituting equation (1.21) into equation (1.20) yields:

[0113] ; (1.22)

[0114] Therefore, in order to solve the average information age, it is also necessary to calculate the expected square of the time interval between the transmission completion of two adjacent target aggregation packets. and the expected interval between the original data packet transmission completion time and the generation time In this embodiment, the original data packet update frequency and the current relay frame aggregation period are still used to obtain 、 , the specific derivation process is as follows:

[0115] Lemma 2: When the raw data packet update frequency of any sensor is And the aggregation period of the relay For the time, The expectation can be calculated as:

[0116] (1.23)

[0117] prove:

[0118] like Figure 6 Given the The specific representation is that due to the sensor The generation of packets follows an exponential distribution, so the time interval between the generation of the last original packet and the end of frame aggregation is The time interval between the start of frame aggregation and the generation of the first original data packet have the same expected value, i.e. Therefore, we can solve for the expected value , instead of As shown in Figure 6, assuming During multiple continuous polymerization No packets are generated within 1 second, after which it Generate the first data packet. Define the time interval from the above continuous aggregation time to the time when data packet 1 is generated as , then you can It is represented by the following function:

[0119] (1.24)

[0120] in, express exist The remainder on represents the floor operator, and obviously there is .

[0121] Through the above variable transformation, we can The probability of ,in, .also, Can be based on The total probability formula for the number of aggregation cycles included in is further expressed as:

[0122] (1.25)

[0123] Then, the above formula can be further written as:

[0124] (1.26)

[0125] Since the data generation follows an exponential distribution, Also follows the parameters The exponential distribution of . Then, we can get:

[0126] (1.27)

[0127] Substituting equation (1.27) into equation (1.26) yields:

[0128] (1.28)

[0129] Then you can get The probability is:

[0130] (1.29)

[0131] therefore, The PDF is:

[0132] (1.30)

[0133] Finally got The expectation is:

[0134] (1.31)

[0135] The proof is complete.

[0136] According to formula (1.10), we can get:

[0137] ; (1.32)

[0138] According to formula (1.18), we can further obtain:

[0139] ; (1.33)

[0140] Finally, the average information age of the original data packets of multiple IoT sensors for frame aggregation is determined based on the expected interval between the transmission completion time of two adjacent target aggregation packets, the expected square of the time interval between the transmission completion time of two adjacent target aggregation packets, and the expected interval between the transmission completion time and the generation time of the original data packet. Specifically, according to equations (1.7) and (1.20), The average AoI can be rewritten as:

[0141] ; (1.34)

[0142] From this deduction, we can know that according to the original data packet update frequency and the current relay frame aggregation period , determine the average information age of multiple IoT sensor raw data packets for frame aggregation .

[0143] Regarding step S103, the calculation formula for the average transmission efficiency of the frame aggregation strategy under the retransmission mechanism is derived as follows:

[0144] According to the frame aggregation strategy, the original relay transmission efficiency is determined, see formula (1.2); according to the signal-to-noise ratio of the data center receiver, the data center's bit error rate is determined; based on the data center's bit error rate and the length of the message in the data packet, the retransmission probability under the retransmission mechanism is determined; based on the time interval distribution parameters of the sensor-generated data packets, the probability of each data packet being aggregated within the aggregation period and the probability that at least one data packet is sent from the sensor to the relay auxiliary device within the aggregation period are determined; based on the probability of each data packet being aggregated within the aggregation period and the probability that at least one data packet is sent from the sensor to the relay auxiliary device within the aggregation period, the probability of data packets being aggregated within the aggregation period is determined; based on the original relay transmission efficiency, the retransmission probability under the retransmission mechanism, and the probability of data packets being aggregated within the aggregation period, the average transmission efficiency of the frame aggregation strategy under the retransmission mechanism is determined.

[0145] Specifically, in practice, when decoding errors occur in the frame aggregation scheme proposed by the relay, it is necessary to consider the case of packet retransmission. For the sake of analysis, assuming that binary phase shift keying (BPSK) is used on the drone, the bit error rate (BER) of the data center can be calculated as:

[0146] (1.35)

[0147] in is the receiver's signal-to-noise ratio (SNR), is a Q function. Then an aggregate frame The probability of transmission failure can be expressed as:

[0148] (1.36)

[0149] If a decoding error occurs in a data center, the aggregated data packet will be retransmitted, and the transmission efficiency becomes:

[0150] (1.37)

[0151] in It is The number of times aggregate packets are transmitted. This means that the A decoding error occurred during the transmission and the aggregate packet was The number of retransmissions was not successfully transmitted to the data center before. In this case, the number of retransmissions is .

[0152] Then, the average transmission efficiency can be given by:

[0153] (1.38)

[0154] It can be further expressed as:

[0155] (1.39)

[0156] in, Indicates Under the condition of The probability can be expressed as:

[0157] (1.40)

[0158] also, yes Data packets in The probability of aggregation during the period is If no packets are generated during this aggregation period, no information will be sent from the relay auxiliary device. Therefore, when The average transmission efficiency is not counted. During the aggregation period, at least one data packet is sent from the sensor to the relay auxiliary device. . Therefore, for any polymerization cycle , the relay auxiliary equipment receives The probability of a data packet is:

[0159] (1.41)

[0160] According to conditional probability, the above formula can be rewritten as:

[0161] (1.42)

[0162] Since the time interval for the sensor to generate data packets follows the parameter independent exponential distribution, so in time The number of packets aggregated in follows the parameter Therefore, the data packets are distributed in the aggregation period. The probability of up-aggregation can be expressed as:

[0163] ;

[0164] That is, ; (1.43)

[0165] in Represents an integer In addition, the event It can be expressed as:

[0166] ; (1.44)

[0167] but It can be calculated by the following formula:

[0168] ; (1.45)

[0169] Substituting equations (1.40) and (1.45) into equation (1.39) yields an expression for the average transmission efficiency of the system that is both complex and difficult to analyze:

[0170] (1.46)

[0171] The goal of the embodiments of the present invention is to maximize the transmission efficiency of relays through a frame aggregation method while ensuring the real-time performance of sensor information, namely:

[0172] (1.47a)

[0173] (1.47b)

[0174] The above optimization problem is to maximize the transmission efficiency of the relay while taking into account decoding errors and retransmission conditions. In addition, constraint (1.47a) specifies that the maximum average AoI of the system should not exceed As mentioned above, the transmission efficiency The expression for is complex and difficult to analyze and optimize. Therefore, the following simplifications and approximations are made.

[0175] According to formula (1.39), we find that:

[0176] (1.48)

[0177] in, yes In the conditions Under expectations, is a random variable. Because It is a The convex function of , according to Jason's inequality, can be obtained:

[0178] (1.49)

[0179] Therefore, the lower bound of formula (1.39) is:

[0180] (1.50)

[0181] According to formula (1.40), it is not difficult to find that The obedience parameter is The geometric distribution of , then:

[0182] (1.51)

[0183] Therefore, Equation (1.50) can be written as:

[0184] (1.52)

[0185] Next, in order to use the optimization tool to find the optimal solution, we will simplify the infinite series in the above formula. Defined as , Defined as , which can be obtained The expression is:

[0186] (1.53)

[0187] Proof: Extract from formula (1.52) You can get:

[0188] (1.54)

[0189] make Then we further get:

[0190] (1.55)

[0191] Based on You can get:

[0192] (1.56)

[0193] make and ,but about The partial derivative of is:

[0194] (1.57)

[0195] because ,so It can be obtained by the following formula:

[0196] (1.58)

[0197] in Equation (1.53) can be combined with equations (1.54) to (1.58) to obtain, and the proof is complete.

[0198] Finally, the optimization problem The following approximation can be made:

[0199] (1.59a)

[0200] (1.59b)

[0201] Among them, this embodiment converts the original problem into the optimization of its lower bound to obtain a suboptimal solution. The expression is complex and therefore difficult to obtain Fortunately, by simplifying Equation (1.52) to Equation (1.53), the optimization problem can be easily obtained using common optimization methods (such as interior point method) The optimal solution of .

[0202] The present invention provides an efficient frame aggregation and relay method that meets the timeliness constraints of IoT information. It uses the average age of information (AoI) as a measure of system performance and frame aggregation. It uses an approximate expression for the average AoI at the sensor and the average relay transmission efficiency, while also considering decoding errors and retransmissions to construct an optimization problem. By solving this optimization problem, that is, solving an analyzable approximate expression for the average transmission efficiency, the frame aggregation period is optimized, thereby achieving the purpose of improving transmission efficiency. Compared with traditional decoding and forwarding methods, the method proposed by the present invention, such as Figure 7 As shown in FIG, the transmission efficiency of the method proposed in the present invention under different AoI thresholds is improved significantly.

[0203] The present application also provides an electronic device, such as Figure 8 As shown, a processor 501 and a memory 502 , wherein the processor 501 and the memory 502 may be connected via a bus or other means.

[0204] The processor 501 may be a central processing unit (CPU). The processor 501 may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or a combination of these chips.

[0205] Memory 502, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the efficient frame aggregation and relay method for meeting IoT information timeliness constraints in the embodiments of the present invention. The processor executes the non-transitory software programs, instructions, and modules stored in the memory to perform various processor functions and data processing.

[0206] The memory 502 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created by the processor, etc. In addition, the memory may include a high-speed random access memory, and may also include a non-transitory memory, such as at least one disk storage device, a flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 502 may optionally include a memory remotely located relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0207] The one or more modules are stored in the memory 502 and when executed by the processor 501, perform the following steps: Figure 1 The illustrated embodiment provides an efficient frame aggregation and relay method that satisfies the timeliness constraints of IoT information.

[0208] For details of the above electronic equipment, please refer to Figure 1 The corresponding descriptions and effects in the embodiments shown can be understood and will not be repeated here.

[0209] This embodiment also provides a computer storage medium storing computer-executable instructions capable of executing any of the above-described method embodiments for efficient frame aggregation and relay that meets IoT information timeliness constraints. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), a flash memory, a hard disk drive (HDD), or a solid-state drive (SSD); the storage medium may also include a combination of the above-described types of memory.

[0210] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. An efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information, characterized by: include: Obtain the original data packet update frequency, the current relay frame aggregation period, the frame aggregation strategy, and the signal-to-noise ratio of the data center receiver; Determine the average information age of multiple IoT sensor original data packets for frame aggregation based on the original data packet update frequency and the current relay frame aggregation period; Determine the average transmission efficiency of the frame aggregation strategy under the retransmission mechanism based on the frame aggregation strategy, the signal-to-noise ratio of the data center receiver, the packet update frequency, and the current relay frame aggregation period; With the goal of maximizing the average transmission efficiency and the condition that the average information age meets the maximum limit, the optimization solution is obtained to obtain the optimal solution for the relay frame aggregation period; The average information age of the original data packets of multiple IoT sensors for frame aggregation is determined based on the original data packet update frequency and the current relay frame aggregation period, including: ； in, represents the average information age, Indicates the expected time interval between the transmission completion of two adjacent target aggregation packets. It represents the expected square of the time interval between the transmission completion of two adjacent target aggregation packets. Indicates the expected interval between the transmission completion time and the generation time of the original data packet, Indicates the original data packet update frequency, represents the aggregation period; Based on the frame aggregation strategy, the signal-to-noise ratio of the data center receiver, the packet update frequency, and the current relay frame aggregation period, the average transmission efficiency of the frame aggregation strategy under the retransmission mechanism is determined, including: ； in, Indicates Under the condition of j-1 The probability of , determined by the signal-to-noise ratio of the data center receiver, For relay auxiliary equipment in time interval n The number of packets received within It is n The number of times an aggregate packet is transmitted, express i The probability that a data packet is aggregated within the aggregation period, Characterizes the original relay transmission efficiency, which is determined by the frame aggregation strategy, 、 and Respectively represent the frame header, message and frame tail of the data packet, ; With the goal of maximizing average transmission efficiency and the condition that the average information age meets the maximum limit, an optimization solution is performed to obtain the optimal solution for the relay frame aggregation period, including: Analyze the average transmission efficiency and determine the lower bound of the average transmission efficiency; The lower bound of the average transmission efficiency is: ； in, is the lower bound of the average transmission efficiency, express , express , , is the bit error rate of the data center, is the signal-to-noise ratio of the receiver, is the Q function, K is the number of sensors served by a relay auxiliary device; The goal is to maximize the lower bound of the average transmission efficiency, and the average information age satisfies the maximum limit as a condition, including: ； ； in, represents the maximum average information age, Represents the average information age.

2. The efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information according to claim 1 is characterized in that: Based on the frame aggregation strategy, the signal-to-noise ratio of the data center receiver, the packet update frequency, and the current relay frame aggregation period, the average transmission efficiency of the frame aggregation strategy under the retransmission mechanism is determined, including: Determine the original relay transmission efficiency based on the frame aggregation strategy; Determine the data center's bit error rate based on the data center receiver's signal-to-noise ratio; Determine the retransmission probability under the retransmission mechanism based on the data center's bit error rate and the length of the message in the data packet; Determine the probability of data packets being aggregated within an aggregation period based on a distribution parameter of the time intervals at which the data packets are generated by the sensors; The average transmission efficiency of the frame aggregation strategy under the retransmission mechanism is determined based on the original relay transmission efficiency, the retransmission probability under the retransmission mechanism, and the probability of data packets being aggregated within the aggregation period.

3. The efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information according to claim 2 is characterized in that: The retransmission probability under the retransmission mechanism is determined based on the data center's bit error rate and the length of the message in the data packet, including: ； in, Indicates Under the condition of j-1 The probability of For relay auxiliary equipment in time interval n The number of packets received within It is n The number of times an aggregate packet is transmitted, , is the bit error rate of the data center, is the signal-to-noise ratio of the receiver, is the Q function, is the length of the message in the packet.

4. The efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information according to claim 3 is characterized in that: Based on the time interval distribution parameters of the sensor-generated data packets, the probability of the data packets being aggregated within the aggregation period is determined, including: Based on the time interval distribution parameters of the sensor-generated data packets, the probability that each data packet is aggregated within the aggregation period and the probability that at least one data packet is sent from the sensor to the relay auxiliary device within the aggregation period are determined as follows: ； ； in, It represents the probability of the i-th data packet being aggregated within the aggregation period. The time interval of the sensor generating data packets follows the parameter The independent exponential distribution of represents the original data packet update frequency, K is the number of sensors served by a relay auxiliary device, so in the aggregation period The number of packets aggregated in follows the parameter Poisson distribution, Indicates that during the aggregation cycle The probability that at least one data packet is sent from the sensor to the relay auxiliary device; The probability of data packets being aggregated within the aggregation period is determined based on the probability of each data packet being aggregated within the aggregation period and the probability that at least one data packet is sent from the sensor to the relay auxiliary device within the aggregation period. The formula is as follows: ； in, It represents the probability that i packets are aggregated within the aggregation period.

5. An efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information according to any one of claims 1 to 4, characterized in that: Based on the original data packet update frequency and the current relay frame aggregation period, the average information age of multiple IoT sensor original data packets for frame aggregation is determined, including: According to the original data packet update frequency and the current relay frame aggregation period, the expected time interval between the completion of transmission of two adjacent target aggregation packets and the expected time interval squared between the completion of transmission of two adjacent target aggregation packets are determined. The target aggregation packet is an aggregation packet containing the original data packet of the same IoT sensor. Determine the expected interval between the transmission completion time and the generation time of the original data packet based on the original data packet update frequency and the current relay frame aggregation period; The average information age of frame aggregation of multiple IoT sensor original data packets is determined based on the expected interval between the transmission completion times of two adjacent target aggregation packets, the expected square of the time interval between the transmission completion times of two adjacent target aggregation packets, and the expected interval between the transmission completion time and the generation time of the original data packet.

6. The efficient frame aggregation relay method that meets the timeliness constraints of Internet of Things information according to claim 5 is characterized in that: Determining the expected time interval between two adjacent target aggregation packet transmission completions and the expected square of the time interval between two adjacent target aggregation packet transmission completions based on the original data packet update frequency and the current relay frame aggregation period includes: ； ； in, Indicates the expected time interval between the transmission completion of two adjacent target aggregation packets. It represents the expected square of the time interval between the transmission completion of two adjacent target aggregation packets. represents the aggregation period, Indicates the original data packet update frequency; Based on the original data packet update frequency and the current relay frame aggregation period, determine the expected interval between the original data packet transmission completion time and the generation time, including: ； in, Indicates the expected interval between the transmission completion time and the generation time of the original data packet.

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