Distributed space-time block coding transmission system and transmission performance analysis method

Abstract

The application provides a kind of distributed space-time block coding transmission system and transmission performance analysis method, the system includes: source node, for transmitting transmission signal;Distributed multiple intelligent reflecting surface IRS, for receiving transmission signal from source node, adjusting the phase of transmission signal, constructing space-time block coding, and distributing the signal after space-time block coding to destination node in a distributed manner;Destination node, for receiving the signal after space-time block coding, decoding the signal after space-time block coding to obtain transmission signal.The application can create line-of-sight line-of-sight link and construct space-time transmission by deploying multiple distributed IRS between source node and destination node, receiving the signal from source node and adjusting the phase to construct space-time block coding, and reflecting to destination node in a distributed manner, to realize reliable transmission of wireless link in the case of limited size and design complexity of transceiver and existence of obstacles in 6G wireless Internet of Things.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a distributed space-time packet coding transmission system and a transmission performance analysis method. Background Technology

[0002] In wireless communication, space-time block coding is often used to transmit multiple copies of a data stream on multiple antennas and to improve the reliability of data transmission by utilizing various received data versions.

[0003] However, in the Beyond 5G (B5G) / 6G era, the emergence of new intelligent services has placed higher demands on ultra-low latency and high reliability. In wireless IoT, due to limitations in transceiver size and design complexity, traditional space-time wireless communication schemes struggle to achieve reliable wireless link transmission in the presence of obstacles. Therefore, effectively improving the reliability of transmission in 6G wireless IoT is a crucial issue. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a distributed space-time packet coding transmission system, comprising:

[0005] The source node is used to transmit signals;

[0006] Multiple distributed intelligent reflecting surfaces (IRS) are used to receive the transmitted signal from the source node, adjust the phase of the transmitted signal to construct space-time block coding, and distribute and reflect the space-time block-coded signal to the destination node.

[0007] The destination node is used to receive the space-time block encoded signal and decode the space-time block encoded signal to obtain the transmission signal.

[0008] According to a distributed space-time block coding system provided by the present invention, the source node is specifically used to determine the IRS with the smallest distance from the source node based on the distance between the source node and the plurality of IRSs; and to transmit transmission signals to the IRS with the smallest distance in multiple time slots during a transmission cycle;

[0009] The IRS has a reflection unit; the reflection unit of the IRS is used to adjust the phase of the transmitted signal to different reflection phase values ​​in different time slots of a transmission cycle, and reflect the phase-adjusted signal to the destination node.

[0010] The target node is specifically used to combine phase-adjusted signals received in different time slots during a transmission cycle, and decode the phase-adjusted signals to obtain the transmission signal.

[0011] According to a distributed space-time block coding system provided by the present invention, the source node includes a first transmitter and a second transmitter; the IRS includes a first IRS with the smallest distance to the first transmitter and a second IRS with the smallest distance to the second transmitter.

[0012] The first transmitter is configured to transmit a first transmit symbol to the first IRS in a first time slot and transmit a second transmit symbol to the first IRS in a second time slot.

[0013] The second transmitter is used to transmit a second transmission symbol to the second IRS in the first time slot and to transmit a first transmission symbol to the second IRS in the second time slot.

[0014] According to a distributed space-time block coding system provided by the present invention, the reflection unit of the first IRS is used to adjust the phase of the first transmitted symbol in the first time slot and reflect it to the destination node, and adjust the phase of the second transmitted symbol in the second time slot and reflect it to the destination node.

[0015] The reflection unit of the second IRS is used to adjust the phase of the second transmitted symbol in the first time slot and reflect it to the target node, and to adjust the phase of the first transmitted symbol in the second time slot and reflect it to the target node.

[0016] According to a distributed space-time block coding system provided by the present invention, the destination node is specifically used to construct a combined signal based on the phase-adjusted signals received in the first time slot and the second time slot in a transmission cycle;

[0017] The combined signal is estimated using a maximum likelihood detector to obtain the first transmitted symbol and the second transmitted symbol.

[0018] The present invention also provides a transmission performance analysis method, the method being used to measure the transmission performance of the distributed space-time block coding transmission system as described above, the method comprising:

[0019] Obtain performance analysis parameters; the performance analysis parameters include at least one of the number of reflection units of the IRS and the transmit power of the source node;

[0020] Based on the performance analysis parameters, output the transmission performance analysis results of the distributed space-time block coding transmission system.

[0021] According to a transmission performance analysis method provided by the present invention, the step of outputting the transmission performance analysis result of the distributed space-time block coding transmission system based on the performance analysis parameters includes:

[0022] The instantaneous received signal-to-noise ratio is calculated by acquiring the first channel coefficient value from the source node to the reflection unit of the IRS, the second channel coefficient value from the reflection unit of the IRS to the destination node, and the transmit power of the source node.

[0023] The probability density function and cumulative distribution function of the end-to-end signal-to-noise ratio are determined based on the instantaneous received signal-to-noise ratio, the transmit power of the source node, and the number of reflection units of the IRS.

[0024] According to a transmission performance analysis method provided by the present invention, the step of outputting the transmission performance analysis result of the distributed space-time block coding transmission system based on the performance analysis parameters further includes:

[0025] The interruption probability of the distributed space-time block coding transmission system is output by simulating the interruption probability based on the number of reflection units of the IRS, the transmit power of the source node, and the interruption threshold.

[0026] The symbol error rate is simulated based on the number of reflection units of the IRS, the transmit power of the source node, the interruption threshold, and the modulation parameters, and the symbol error rate of the distributed space-time block coding transmission system is output.

[0027] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the transmission performance analysis method as described in any of the preceding claims.

[0028] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the transmission performance analysis method as described in any of the preceding claims.

[0029] This invention, through the deployment of multiple distributed intelligent reflective surfaces (IRS) between the source and destination nodes, simultaneously receives the transmission signal from the source node, adjusts the phase to construct space-time packet coding, and then reflects it to the destination node in a distributed manner. This enables the creation of line-of-sight links and the construction of space-time transmission, thereby achieving reliable wireless link transmission for 6G wireless IoT even when transceiver size and design complexity are limited and obstacles exist. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is one of the structural schematic diagrams of the distributed space-time packet coding transmission system provided in the embodiments of the present invention;

[0032] Figure 2 This is the second schematic diagram of the structure of the distributed space-time packet coding transmission system provided in the embodiment of the present invention;

[0033] Figure 3 This is a flowchart illustrating the transmission performance analysis method provided in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0036] Figure 1 This is one of the structural schematic diagrams of the distributed space-time packet coding transmission system provided in an embodiment of the present invention. (Refer to...) Figure 1 This invention provides a distributed space-time packet coding transmission system, comprising:

[0037] Source node 101 is used to transmit signals;

[0038] Distributed multiple smart reflectors IRS102 are used to receive the transmitted signal from the source node, adjust the phase of the transmitted signal to construct space-time block coding, and distribute and reflect the space-time block coded signal to the destination node 103.

[0039] The destination node 103 is used to receive the space-time block encoded signal and decode the space-time block encoded signal to obtain the transmission signal.

[0040] Specifically, a source node can include at least two transmission sources, and a distributed space-time block coding transmission system can include K sources S1, S2, ..., S...k A destination D, and K IRSs, R1, R2, ..., R k Multiple sources can transmit signals to a destination through multiple IRSs. IRSs can be used to adjust the phase and establish a robust wireless link. The destination node (i.e., the receiver) can perform space-time coding through simple mathematical operations, thereby realizing space-time coded wireless communication based on distributed multi-IRS assistance.

[0041] It should be noted that both the source and destination can be equipped with a single antenna. The direct link between the source and destination is blocked due to obstacles. K sources can each utilize K IRSs to transmit uncoded data to the destination. Each IRS can be connected to an IRS controller, which adjusts the phase of each IRS and synchronizes the phase shift configuration across the entire system via high-speed backhaul. This allows for rapid IRS phase changes within each time slot, ignoring the time required for phase adjustment. Furthermore, it can be assumed that perfect global channel state information (CSI) is valid on both the IRS controller and the sources. To obtain CSI, existing channel estimation methods for (multi-)IRS-assisted systems can be employed.

[0042] Intelligent reflective surface (IRS) systems possess real-time programmability and phase tuning capabilities, enabling direct modulation of reflected or transmitted electromagnetic waves without requiring modulation of traditional RF chains. This characteristic offers a potential affordable evolutionary space-time transmission method that can replace wireless repeaters as the medium for space-time coding of transmitted signals, thereby achieving reliable wireless network transmission. However, current IRS solutions for space-time wireless communication place high demands on transmitter design, making them unsuitable for 6G wireless IoT systems with simple transceiver capabilities and large-scale connectivity.

[0043] In this embodiment of the invention, by deploying multiple distributed intelligent reflective surfaces (IRS) between the source node and the destination node, simultaneously receiving the transmission signal emitted from the source node and adjusting the phase to construct space-time packet coding, and then reflecting it to the destination node in a distributed manner, line-of-sight links and space-time transmission can be created. This enables reliable wireless link transmission for 6G wireless IoT even when transceiver size and design complexity are limited and obstacles exist.

[0044] In one optional embodiment, the source node is specifically configured to determine the IRS with the smallest distance from the source node based on the distance between the source node and the plurality of IRSs; transmit a transmission signal to the IRS with the smallest distance in multiple time slots within a transmission cycle; the IRS has a reflection unit; the reflection unit of the IRS is configured to adjust the phase of the transmission signal to different reflection phase values ​​in different time slots within a transmission cycle, and reflect the phase-adjusted signal to the destination node; the destination node is specifically configured to combine the phase-adjusted signals received in different time slots within a transmission cycle, and decode the phase-adjusted signals to obtain the transmission signal.

[0045] In wireless transmission scenarios with high reliability requirements, large-scale deployment of IRS is necessary. The number of transmitters in the collaborative transmission encoding process can be less than the number of IRSs in the surrounding environment. During wireless transmission, the transmitters participating in the encoding transmission can determine the IRS with the smallest distance (i.e., the closest distance) and transmit the transmission signal to the IRS with the smallest distance.

[0046] It should be noted that, due to the high path loss experienced by the signal reflected from the IRS, the power of the signals reflected two or more times by the IRS can be ignored in the system model, and only the first reflection is considered. K IRSs can have M reflection units, and the number of transmission units in the k-th IRS can be M. k Each IRS has M k Each reflecting unit adjusts its phase to a common reflection phase value, and each IRS can adjust its reflection phase value differently in different time slots within a transmission cycle. The destination node (i.e., the receiver) can combine the signals received in different time slots within a transmission cycle to decode and recover the original transmitted signal. In this embodiment of the invention, distributed space-time block coding can be achieved by adjusting the phase, and the coding can occur within T time slots of a transmission cycle.

[0047] It can be adopted and Let S and D represent the small-scale fading channel coefficients from the source S to the m-th reflection unit of the k-th IRS and from that reflection unit to the destination D, respectively. Under the Rayleigh fading channel assumption, we can have: in This can represent a mean of zero and a variance of σ. 2 The complex Gaussian distribution of the complex channel coefficients can be expressed by their polarity as follows: Where g km and f km It is the magnitude of the channel coefficient, ψ km and They are and The phase of the signal. The distance between reflecting units is equal to or greater than half the signal wavelength, so the fading channel can be approximated as independent and identically distributed (iid) fading. The reflection coefficient of the m-th reflecting unit of the k-th IRS in time slot t can be expressed as... Among them κ km ∈[0,1] and These are the amplitude coefficient and the phase shift, respectively.

[0048] When measuring the transmission performance limit of a system, we can assume that for k = 1, ..., K and m = 1, ..., M k ,κ km =1 and φ km It can vary continuously in [0, 2π). Therefore, the reflection coefficient of the m-th reflecting element of the k-th IRS within one emission cycle can be defined as... make For source S k The transmitted symbol in the t-th time slot, P S For source S k The transmission power.

[0049] The following is a detailed explanation of the distributed space-time packet coding transmission scheme based on multiple IRS:

[0050] We can assume a quasi-static fading channel, where the channel remains constant over T time slots within one transmission period. For k = 1, ..., K, the source S... k Within time slot t, it can send signals to nearby IRSRs. k Emit symbol x k,t ,and in Then the IRS is controlled to reflect the signal towards D. All IRSs are controlled to guide their beams to the destination so they do not interfere with each other, and a superposition (combination) of all multipath signals can be received at D. Therefore, the received signal in time slot t can be written as...

[0051]

[0052] Where n t The mean of time slot t is 0 and the variance is σ. 2 Additive white Gaussian noise.

[0053] By using a generalized orthogonal design method, distributed space-time block codes that encode any number of signal streams using IRSs can be realized. For the general case of K sources and IRSs, S... k Within one transmission cycle, to IRS R k Transmit signal Signal phase adjusted by IRS k Back reflection, in which Then, D receives K transmitted signals from different sources in each time slot and superimposes (combines) them after reflection by the IRS. The receiver combines the signals received in different time slots of a transmission period to obtain each transmitted symbol.

[0054] As an example of the general scheme for implementing distributed STBC encoding using IRS, a DSTBC encoding scheme for encoding two signals is given below:

[0055] In one optional embodiment, the source node includes a first transmitter and a second transmitter; the IRS includes a first IRS with the smallest distance to the first transmitter and a second IRS with the smallest distance to the second transmitter; the first transmitter is configured to transmit a first transmit symbol to the first IRS in a first time slot and transmit a second transmit symbol to the first IRS in a second time slot; the second transmitter is configured to transmit a second transmit symbol to the second IRS in the first time slot and transmit a first transmit symbol to the second IRS in the second time slot.

[0056] Specifically, a distributed Alamouti transmission scheme with dual IRS encoding two signals can be implemented by setting K=2 and T=2. Here, S1 can represent the first transmitter, S2 the second transmitter, s1 the first transmitted symbol, and s2 the second transmitted symbol.

[0057] The transmitted symbol in one transmission cycle can be represented as s1 and s2 can be expressed by polarity expressions as follows: and Specifically, in the first time slot, S1 and S2 transmit symbols s1 and s2 to their nearby IRS R1 and R2, respectively. In the second time slot, S1 and S2 transmit symbols s2 and s1 to their nearby IRS R1 and R2, respectively.

[0058] In one optional embodiment, the reflection unit of the first IRS is configured to adjust the phase of the first transmitted symbol in a first time slot and reflect it to the target node, and adjust the phase of the second transmitted symbol in a second time slot and reflect it to the target node; the reflection unit of the second IRS is configured to adjust the phase of the second transmitted symbol in the first time slot and reflect it to the target node, and adjust the phase of the first transmitted symbol in the second time slot and reflect it to the target node.

[0059] Specifically, within the first time slot, R1 and R2 can be adjusted to their respective phases. and According to equation (1), the received signal of the first time slot can be rewritten as follows:

[0060] y1=A1s1+A2s2+n1 (2)

[0061] in k = 1, 2. According to the Alamouti transmission scheme, in the second time slot, S1 and S2 transmit symbols s2 and s1 to their respective neighboring IRSR1 and R2, and can adjust the phases of R1 and R2 accordingly. and The received signal in the second time slot can be rewritten as

[0062]

[0063] In one optional embodiment, the target node is specifically configured to construct a combined signal based on the phase-adjusted signals received in the first and second time slots of a transmission cycle; and to estimate the combined signal using a maximum likelihood detector to obtain the first transmission symbol and the second transmission symbol.

[0064] The differential space-time block code (DSTBC) receiver (i.e., the destination node) can directly combine the signals received in two time slots within a transmission cycle (2)(3) and construct the combined signal as follows:

[0065]

[0066]

[0067] Then the symbol and s1 and s2 can be estimated using a maximum likelihood detector.

[0068] It should be noted that similar steps can be used to obtain distributed STBC transmission schemes that encode three- and four-channel signals using multiple IRSs. For these two common space-time transmission schemes, four symbols are transmitted within eight time slots, resulting in a transmission rate of 1 / 2. The classic Alamouti coding scheme with K=2 transmits two symbols within two time slots, resulting in a transmission rate of 1. Although the K=3 and K=4 schemes suffer from a loss in transmission rate, they achieve higher coding gain.

[0069] Figure 2 This is the second schematic diagram of the distributed space-time packet coding transmission system provided in this embodiment of the invention. (Refer to...) Figure 2The transmitter controller can connect to multiple source nodes S, and the transmitter controller can connect to an IRS controller, which in turn can connect to multiple IRSs. There are physical obstacles between the source nodes and the destination nodes. Within one transmission cycle, source node S1 can transmit signal G1[…, s2, s1, s4, s3, s2, s1] to the nearest IRS1. IRS1 can perform space-time modulation to adjust the phase of the transmitted signal and reflect it. The destination node D can receive the reflected signal F1[…, -s2*, s1*, -s4, -s3, -s2, s1]. k Within a single transmission cycle, it can be directed to the nearest IRS. k Transmit signal G k […,s1,s2,s3,s4,s1,s2], IRS k Space-time debugging can be performed to adjust the phase of the transmitted signal and reflect it out, so that the destination node D can receive the reflected signal F. k […, s1*, s2*, -s3, s4, s1, s2]. The receiver can use the channel estimation methods A1, A2, ..., A of the multi-IRS assisted system to estimate the signal received by the destination node. k , to obtain signal combination

[0070] Figure 3 This is a flowchart illustrating the transmission performance analysis method provided in an embodiment of the present invention. (Refer to...) Figure 3 This invention provides a transmission performance analysis method, which is used to measure the transmission performance of the distributed space-time block coding transmission system in this invention embodiment. Specifically, the method may include the following steps:

[0071] Step 301: Obtain performance analysis parameters; the performance analysis parameters include at least one of the number of reflection units of the IRS and the transmit power of the source node;

[0072] Step 302: Based on the performance analysis parameters, output the transmission performance analysis results of the distributed space-time block coding transmission system.

[0073] The transmission performance analysis method of this invention can be executed by a control terminal. The control terminal can be built into the distributed space-time block coding transmission system or can be independent of the distributed space-time block coding transmission system. The control terminal and the distributed space-time block coding transmission system are connected for communication.

[0074] Performance analysis parameters refer to parameters used to analyze the transmission performance of the system, and may include IRS reflection unit data, source node transmit power, etc. The control terminal can acquire the performance analysis parameters input to the control terminal, and thus output the transmission performance analysis results for the distributed space-time packet coding transmission system.

[0075] In an optional embodiment, step 301 may include: obtaining a first channel coefficient value from the source node to the reflection unit of the IRS, a second channel coefficient value from the reflection unit of the IRS to the destination node, and the transmit power of the source node; calculating the instantaneous received signal-to-noise ratio; and determining the probability density function and cumulative distribution function of the end-to-end signal-to-noise ratio based on the instantaneous received signal-to-noise ratio, the transmit power of the source node, and the number of reflection units of the IRS.

[0076] The first channel coefficient value from the source node to the reflection unit of the IRS can be expressed as g. 1m The second channel coefficient value from the reflection unit of the IRS to the destination node can be expressed as f 1m The transmit power of the source node can be expressed as P s The variance is σ 2 .

[0077] Based on (4) and (5) and considering the symmetry of the symbols, the instantaneous received signal-to-noise ratio can be obtained as follows:

[0078]

[0079] Therefore, the general case for encoding with K IRSs can be easily obtained, and the instantaneous received signal-to-noise ratio is:

[0080]

[0081] Where, ρ s =P s / σ 2 .

[0082] In this embodiment of the invention, the probability density function and cumulative distribution function of the end-to-end signal-to-noise ratio (SNR) can be determined based on parameters such as the instantaneous received signal-to-noise ratio (SNR), the transmit power of the source node, and the reflection unit data of the IRS. To obtain precise expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the end-to-end SNR (Signal to Interference plus Noise Ratio, SNR) of the IRS-assisted DSTBC system, several important statistical representations can be derived first.

[0083] Due to g km and f km They all follow independent Rayleigh distributions with a variance of 1, therefore their product is a bi-Rayleigh distribution RV. Therefore, A k k = 1, 2, ..., K is M k The sum of independent and identical double Rayleigh processes, so A k The closed-form expression for PDF and CDF can be written as

[0084]

[0085]

[0086] in and Then, By substituting into (8) and (9), we can obtain A. k PDF and CDF of the square of the modulus are

[0087]

[0088]

[0089] X can be obtained from equation (10) k It is a generalized gamma-distributed random variable (GGRV). Let To obtain the closed-form expression for the end-to-end SNR, the PDF and CDF of Z can be derived first. In this embodiment of the invention, the exact closed-form expressions for the PDF and CDF of the sum of N GG RVs are derived for the first time using the multivariate Fox's H function.

[0090] Theorem 1: PDF and CDF can be represented as respectively

[0091]

[0092]

[0093] Proof: First, we can use Fox's H function to convert X in (10) k The PDF was rewritten as

[0094]

[0095] Therefore, X k The moment generating function (MGF) can be expressed as:

[0096]

[0097] (15) can be rewritten as

[0098]

[0099] Then (16) can be further rewritten as

[0100]

[0101] The MGF of Z can be represented as

[0102]

[0103] Substituting (17) into (18), we can get

[0104]

[0105] With the help of Fox's definition of the H function, (19) can be rewritten as

[0106]

[0107] Therefore, the PDF of Z can be represented by the inverse Laplace transform as follows:

[0108] f Z (z)=L -1 [M Z (s);z] (21)

[0109] Substituting (20) into (21) and using Fubini's theorem to change the order of integration, we can obtain

[0110]

[0111] make By setting sz = -a, I1 can be rewritten as

[0112]

[0113] Therefore, (23) can be solved as follows:

[0114]

[0115] Substituting (24) into (23), we can get

[0116]

[0117] According to the definition of the multivariable Fox's H function, we can obtain (12).

[0118] Z's CDF can be accessed through M Z The inverse Laplace transform of (s) / s is obtained. Following a similar procedure to solve for the PDF of Z, we can obtain (13). Proof complete.

[0119] Corollary 1: The closed-form expressions for the PDF and CDF of the end-to-end SNR of the IRS auxiliary system are as follows:

[0120]

[0121]

[0122]

[0123] Proof: Combining (7) and the definition of the cumulative distribution function, and after some algebraic operations, the CDF of ρ can be expressed as the CDF of Z.

[0124]

[0125] Substituting (13) into (28), we get (27).

[0126] Combining (28) with the relationship between CDF and PDF, we can have

[0127]

[0128] By differentiating (29), the PDF of ρ can be...

[0129]

[0130] Substituting (12) into (30), we get (26). Proof complete.

[0131] In this embodiment of the invention, by deriving the statistical characteristics of the channel, the outage probability (OP) and symbol error rate (SER) in closed form can be derived.

[0132] In an optional embodiment, step 301 may further include: performing an interruption probability simulation based on the number of reflection units of the IRS, the transmit power of the source node, and the interruption threshold, and outputting the interruption probability of the distributed space-time block coding transmission system; and performing a symbol error rate simulation based on the number of reflection units of the IRS, the transmit power of the source node, the interruption threshold, and the modulation parameters, and outputting the symbol error rate of the distributed space-time block coding transmission system.

[0133] Specifically, the control terminal can acquire IRS reflection unit data, source node transmit power, and interruption threshold input to the control terminal for simulation, and output the system's interruption probability. The control terminal can also perform simulation based on IRS reflection unit data, source node transmit power, interruption threshold, and modulation parameters, and output the system's symbol error rate. In this embodiment of the invention, the transmission performance analysis results, such as the interruption probability and symbol error rate, simulated and output by the control terminal can be used to measure the transmission performance of the system.

[0134] (1) Probability of interruption

[0135] The probability of interruption can refer to the received signal-to-noise ratio being lower than a given threshold ρ. th The probability of (i.e., the interrupt threshold). Therefore, the OP can obtain the following:

[0136] P out =P(ρ<ρ) th ), (31)

[0137] or equivalent to

[0138] P out =F ρ (ρ th (32)

[0139] Substituting (27) into the equation, we can obtain the OP of the IRS auxiliary system as follows:

[0140]

[0141] It is evident that as the number of IRS reflective elements increases, wireless communication transmission conditions improve, and the probability of interruption decreases. Furthermore, as the transmit power increases, the probability of interruption also decreases.

[0142] Proposition 1: Asymptotically, at high signal-to-noise ratios, the interruption probability can be expressed as:

[0143]

[0144] in

[0145] Proof: The expression for OP in (33) can be represented as a multiple Merlin-Barnes integral. Then, by calculating the integrand at the dominant poles... The residue can be asymptotically obtained when SNRρ s The probability of interruption as we approach infinity.

[0146] Based on (A1), it can be further explained that the interruption probability decreases as the number of reflective elements in the IRS increases, and the interruption probability also decreases as the transmit power increases.

[0147] Note 2: For the interrupt diversity order Gout ,have According to (A1), it can be observed that Therefore, the interrupt diversity order can be expressed as: in Will Substituting and simplifying, the diversity order can be expressed as: in It can be seen that the diversity order is a linearly increasing function of the number of reflection units.

[0148] (2) Symbol error rate

[0149] To measure the transmission performance of the distributed space-time block coding transmission system in this embodiment of the invention, another important indicator is SER.

[0150]

[0151] Where c and d are modulation-specific parameters. For example, (c,d) = (1,2) represents binary phase shift keying (BPSK), (c,d) = (2,1) represents quaternary quadrature amplitude modulation (4QAM) or quadrature phase shift keying (QPSK), and (c,d) = (3 / 2,2 / 5) represents quaternary pulse amplitude modulation (4-PAM).

[0152] Theorem 2: The closed-form of the SER of an IRS-assisted system can be expressed as:

[0153]

[0154] Proof: Let (34) can be rewritten as

[0155]

[0156] Substituting (27) into (36), we can obtain

[0157]

[0158] in

[0159]

[0160] Using the definition of the multivariable Fox's H function and changing the order of integration, (38) can be rewritten as

[0161]

[0162] in

[0163]

[0164] (40) can be further solved as follows:

[0165]

[0166] Substituting (41) into (39), we can obtain

[0167]

[0168]

[0169] Using the definition of the multivariable Fox H function, (42) can be rewritten as follows:

[0170]

[0171] Substituting (43) into (37), we get (35). Proof complete.

[0172] As can be seen from (35), SER decreases with increasing transmit power. In addition, an IRS system equipped with more reflective elements will also result in a lower SER.

[0173] Corollary 2: Asymptotically, at high signal-to-noise ratios, SER can be expressed as...

[0174]

[0175] Proof: The expression for OP in (33) can be represented as a multiple Merlin-Barnes integral. Then, by calculating the integrand at the dominant poles... The residue can be asymptotically obtained when SNRρ s SER at →∞.

[0176] Based on (44), it can be seen more intuitively that SER decreases with the increase of the number of reflective units of IRS, and in addition, the interruption probability decreases with the increase of transmit power.

[0177] Note 3: For the SER diversity order G SER ,have According to (44), we can obtain Therefore, the interrupt diversity order can be expressed as: in Will Substituting and simplifying, the SER order can be expressed as in Similarly, it can be concluded from the high signal-to-noise ratio asymptotic expression of SER that the diversity order is a linearly increasing function of the number of reflection units.

[0178] In this embodiment of the invention, a line-of-sight link is created using a distributed intelligent reflector. Simultaneously, the transmitted signal from the source node is received, and space-time block coding is constructed by adjusting the phase. The signal is then reflected to the destination node, resulting in a distributed space-time coded transmission system for multiple IRS-assisted transmission. To effectively analyze the wireless transmission performance of the system scheme, the closed-form expressions for the outage probability and symbol error rate are derived. To analyze the performance limits of the system, asymptotic expressions for the outage probability and symbol error rate under high signal-to-noise ratio conditions, as well as diversity gain, are also derived. Thus, the effectiveness of the distributed space-time coded transmission system in this embodiment of the invention for achieving reliable wireless transmission is theoretically proven.

[0179] Figure 4 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 4 As shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430, and a communication bus 440, wherein the processor 410, the communication interface 420, and the memory 430 communicate with each other via the communication bus 440. The processor 410 can call logical instructions in the memory 430 to execute a transmission performance analysis method, the method including:

[0180] Obtain performance analysis parameters; the performance analysis parameters include at least one of the number of reflection units of the IRS and the transmit power of the source node;

[0181] Based on the performance analysis parameters, output the transmission performance analysis results of the distributed space-time block coding transmission system.

[0182] Furthermore, the logical instructions in the aforementioned memory 430 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0183] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the transmission performance analysis methods provided by the methods described above, the methods comprising:

[0184] Obtain performance analysis parameters; the performance analysis parameters include at least one of the number of reflection units of the IRS and the transmit power of the source node;

[0185] Based on the performance analysis parameters, output the transmission performance analysis results of the distributed space-time block coding transmission system.

[0186] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0187] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0188] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A distributed space-time packet coding transmission system, characterized in that, include: The source node is used to transmit signals; Distributed multiple intelligent reflectors (IRS) are used to receive the transmitted signal from the source node, adjust the phase of the transmitted signal to construct space-time block coding, and distribute the space-time block-coded signal to the destination node. The destination node is used to receive the space-time block encoded signal and decode the space-time block encoded signal to obtain the transmission signal.

2. The system according to claim 1, characterized in that, The source node is specifically used to determine the IRS with the smallest distance from the source node based on the distance between the source node and the plurality of IRSs; and to transmit a transmission signal to the IRS with the smallest distance in multiple time slots within a transmission cycle; The IRS has a reflection unit; the reflection unit of the IRS is used to adjust the phase of the transmitted signal to different reflection phase values ​​in different time slots of a transmission cycle, and reflect the phase-adjusted signal to the destination node. The target node is specifically used to combine phase-adjusted signals received in different time slots during a transmission cycle, and decode the phase-adjusted signals to obtain the transmission signal.

3. The system according to claim 2, characterized in that, The source node includes a first transmitter and a second transmitter; the IRS includes a first IRS with the smallest distance to the first transmitter and a second IRS with the smallest distance to the second transmitter. The first transmitter is configured to transmit a first transmit symbol to the first IRS in a first time slot and transmit a second transmit symbol to the first IRS in a second time slot. The second transmitter is used to transmit a second transmission symbol to the second IRS in the first time slot and to transmit a first transmission symbol to the second IRS in the second time slot.

4. The system according to claim 3, characterized in that, The reflection unit of the first IRS is used to adjust the phase of the first transmitted symbol in the first time slot and reflect it to the target node, and to adjust the phase of the second transmitted symbol in the second time slot and reflect it to the target node. The reflection unit of the second IRS is used to adjust the phase of the second transmitted symbol in the first time slot and reflect it to the target node, and to adjust the phase of the first transmitted symbol in the second time slot and reflect it to the target node.

5. The system according to claim 4, characterized in that, The target node is specifically used to construct a combined signal based on the phase-adjusted signals received in the first and second time slots of a transmission cycle. The combined signal is estimated using a maximum likelihood detector to obtain the first transmitted symbol and the second transmitted symbol.

6. A method for analyzing transmission performance, characterized in that, The method is used to measure the transmission performance of a distributed space-time block coded transmission system as described in any one of claims 1-5, and the method includes: Obtain performance analysis parameters; the performance analysis parameters include at least one of the number of reflection units of the IRS and the transmit power of the source node; Based on the performance analysis parameters, output the transmission performance analysis results of the distributed space-time block coding transmission system.

7. The method according to claim 6, characterized in that, The step of outputting the transmission performance analysis results of the distributed space-time block coding transmission system based on the performance analysis parameters includes: The instantaneous received signal-to-noise ratio is calculated by acquiring the first channel coefficient value from the source node to the reflection unit of the IRS, the second channel coefficient value from the reflection unit of the IRS to the destination node, and the transmit power of the source node. The probability density function and cumulative distribution function of the end-to-end signal-to-noise ratio are determined based on the instantaneous received signal-to-noise ratio, the transmit power of the source node, and the number of reflection units of the IRS.

8. The method according to claim 7, characterized in that, The step of outputting the transmission performance analysis results of the distributed space-time block coding transmission system based on the performance analysis parameters further includes: The interruption probability of the distributed space-time block coding transmission system is output by simulating the interruption probability based on the number of reflection units of the IRS, the transmit power of the source node, and the interruption threshold. The symbol error rate is simulated based on the number of reflection units of the IRS, the transmit power of the source node, the interruption threshold, and the modulation parameters, and the symbol error rate of the distributed space-time block coding transmission system is output.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the transmission performance analysis method as described in any one of claims 6 to 8.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the transmission performance analysis method as described in any one of claims 6 to 8.

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