Deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks

Abstract

The present invention provides a deterministic routing decision method based on real-time performance analysis of a wireless multi-hop network. The method collects a plurality of real-time service flows with different source-destination node pairs generated by a terminal in the wireless multi-hop network at the same time, and calculates the signal-to-interference-to-noise ratio of a wireless link between wireless nodes in the wireless multi-hop network; calculates link reliability and link effective service process; obtains a closed expression of the relationship between an upper boundary of an N-hop path delay and a default probability, and then obtains a hop number-delay relationship, and obtains a real-time service delay threshold; forms an optimization problem of maximizing the number of real-time services transmitted simultaneously in the wireless multi-hop network; obtains K shortest paths that meet delay, capacity and reliability constraints; and obtains an optimal path. The method establishes a performance analysis model for reliable transmission in view of the high time-variability of wireless links, and the analysis result is more in line with the characteristics of wireless multi-hop networks; compared with the existing routing decision method, the method is time-saving and deterministic.

Description

Technical Field

[0001] The invention relates to a deterministic routing decision method based on real-time performance analysis of a wireless multi-hop network, belonging to the technical field of communication networks. Background Art

[0002] With the emergence of real-time application scenarios such as the Industrial Internet and the Tactile Internet such as telemedicine, various terminals are no longer limited to simple connections. At the same time, bandwidth-intensive and real-time multimedia traffic such as VR / AR (virtual reality / access reality) and 4K / 8K ultra-high-definition video has emerged on a large scale, making wireless networks increasingly complex. Wireless networks face the dual challenges of supporting large traffic and providing reliable services for real-time multimedia applications.

[0003] In response to the above challenges, wireless multi-hop network systems need to effectively solve the problem of maximizing the number of real-time services transmitted simultaneously. However, wireless multi-hop networks have inherent characteristics that may affect user experience, mainly the highly time-varying characteristics of wireless channels, which affect the reliability and effectiveness of real-time service transmission, and thus cause perceptible damage.

[0004] Traditional routing decision methods, due to the relatively incomplete consideration of influencing factors in the performance analysis of wireless multi-hop networks and the neglect of the highly time-varying characteristics of wireless channels, have the problem of long time consumption for real-time service transmission and the need to improve reliability and effectiveness.

[0005] The above problems are issues that should be considered and solved in the deterministic routing decision process of wireless multi-hop networks. Summary of the invention

[0006] The purpose of the present invention is to provide a deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks to solve the problem that the existing routing decision method in the prior art does not take into account the highly time-varying characteristics of the wireless channel, resulting in a long time consumption for real-time service transmission, and the reliability and effectiveness need to be improved.

[0007] The technical solution of the present invention is:

[0008] A deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks comprises the following steps:

[0009] S1. Collect multiple real-time service flows with different source-destination node pairs generated by terminals at the same time in the wireless multi-hop network, and calculate the wireless link signal-to-interference-to-noise ratio (SINR) between wireless nodes in the wireless multi-hop network. ij ;

[0010] S2: SINR of the wireless link obtained from step S1 ij, calculate the link reliability P n , define the link effective service process, and according to the link reliability P n Calculation link effective service process

[0011] S3: Link effective service process obtained from step S2 Through the random network calculation method, according to the convolution theorem, the real-time service arrival process is obtained Effective service process provided The closed expression of the relationship between the upper bound of the delay of an N-hop path and the default probability is obtained. Then we get the hop count-delay relationship, and the N-hop real-time service delay threshold w is obtained from the hop count-delay relationship N ;

[0012] S4, considering the delay, capacity and reliability constraints, forming an optimization problem of maximizing the number of real-time services transmitted simultaneously in a wireless multi-hop network;

[0013] S5. The real-time service delay threshold corresponding to each hop value obtained in step S3 excludes the path that exceeds the maximum real-time service delay, and obtains K shortest paths that meet the delay, capacity and reliability constraints of step S4 based on K-shortest paths;

[0014] S6. Search the K shortest paths determined in step S5 by exhaustive method to solve the optimization problem of maximizing the number of real-time services transmitted simultaneously in the wireless multi-hop network and obtain the optimal path.

[0015] Furthermore, in step S1, the signal-to-interference-and-noise ratio (SINR) of the wireless link between the wireless nodes is calculated. ij Specifically, in a wireless multi-hop network, the wireless links are independent of each other and all obey Rayleigh fading. Considering the complexity of calculating global interference, only the interference from one-hop neighbor nodes is considered. Then the SINR received at the receiving node j is ij It is expressed as:

[0016]

[0017] in, is the received signal strength of wireless node j in time slot t, d ij d kj are the Euclidean distances between wireless nodes i and j, and between wireless nodes k and j, respectively. α is the path loss index. ij |、|h kj | are the Rayleigh fading channel gains of the link between wireless node i and wireless node j, and the link between wireless node k and wireless node j, respectively, N 0 is the noise power; V jis the set of one-hop neighbor nodes that interfere with wireless node j.

[0018] Further, in step S2, the wireless link signal to interference and noise ratio SINR obtained in step S1 is ij , the reliability of wireless multi-hop network links is analyzed. Specifically, the reliability of link n in the wireless multi-hop network is P n , defined as the signal-to-interference-plus-noise ratio (SINR) of the wireless link n between wireless nodes i and j ij Greater than the threshold γ 0 Probability:

[0019]

[0020] in, is the received signal strength of wireless node j in time slot t, d ij d kj are the Euclidean distances between wireless nodes i and j, and between wireless nodes k and j, respectively. α is the path loss index. ij |、|h kj | are the Rayleigh fading channel gains of the link between wireless node i and wireless node j, and the link between wireless node k and wireless node j, respectively, N 0 is the noise power; V j is the set of one-hop neighbor nodes that interfere with wireless node j.

[0021] Further, in step S2, a link effective service process is defined, specifically, the link effective service process is defined as the maximum rate that the wireless multi-hop network link can transmit under reliable conditions in a certain time slot, and the link effective service process provided by the link n between the wireless node i and the wireless node j within the time (τ, t) for:

[0022]

[0023] in, P represents the link effective service process provided by link n in the exponential domain within the time (τ, t), n represents the reliability of wireless multi-hop network link n, S n (τ, t) represents the maximum rate of link n in the bit-domain wireless multi-hop network within the time (τ, t), B is the channel bandwidth, γ n，u is the received signal strength of channel n in time slot u;

[0024] Further, in step S3, a random network calculation method based on the link effective service process is used to obtain the real-time service arrival process according to the convolution theorem. Effective service process provided The closed expression of the relationship between the upper bound of the real-time service delay and the default probability is obtained, and then the hop count-delay relationship is obtained, which is:

[0025] S31, within the time (τ, t) on the wireless link n, based on network calculation, the cross real-time service cumulative arrival process of the wireless multi-hop network is obtained Combined with the convolution theorem, we can get Effective service process provided

[0026] S31, within the time (τ, t) on the wireless link n, based on network calculation, the cross real-time service cumulative arrival process of the wireless multi-hop network is obtained Combined with the convolution theorem, we can get Effective service process provided

[0027] S32: Valid service process obtained from step S31 Derive the end-to-end delay default probability of a real-time data flow passing through an N-hop path

[0028]

[0029] in, is the real-time service delay, w N is the N-hop real-time service delay threshold, e is the exponential value, σ(s) is the arrival rate of the real-time service, σ c (s) is the cross-real-time service arrival rate, ρ(s) is the burst size of the cross-real-time service, ρ c (s) is the burst size of cross real-time services, S is a free parameter, 0<s<1; for ease of expression, let the variable N ≥ 2, let the variable P n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function, V n+1 (s) is the variable V n (s)’s next hop variable, V N (s) is the Nth jump variable;

[0030] S33, let the right side of formula (6) obtained in step S32 be equal to constant c, and then obtain the relationship between the number of hops and the delay when the real-time data flow passes through an N-hop end-to-end path:

[0031]

[0032] Among them, w N is the N-hop real-time service delay threshold, s is a free parameter, 0<s<1, σ(s) is the arrival rate of the real-time service, σ c (s) is the cross-real-time service arrival rate, ρ(s) is the burst size of the cross-real-time service, and for ease of expression, let the variable Let the variable N ≥ 2, ρ c (s) is the burst size of cross real-time services, let the variable V n+1 (s) is the variable V n (s)’s next hop variable, V N (s) is the Nth jump variable, P n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function.

[0033] Further, in step S31, a random network calculation method based on the link effective service process is used to obtain the real-time service arrival process according to the convolution theorem. Effective service process provided Specifically,

[0034] S311, within the time (τ, t) on the wireless link n, based on network calculation, the cross real-time service cumulative arrival process of the wireless multi-hop network is obtained It is expressed as:

[0035]

[0036] in, The priority of wireless link n in the bit domain is p i The arrival process of real-time business, p i 、p j are the priorities of real-time data stream i and real-time data stream j at wireless link n, The priority of wireless link n in the index domain is p i The arrival process of cross-real-time business;

[0037] S312, combined with the convolution theorem, it is obtained that link n can be a real-time service arrival process within the time (τ, t) Effective service process provided for:

[0038]

[0039] Among them, S n(τ, t) represents the service process provided by link n in the bit-domain wireless multi-hop network within the time (τ, t), P represents the service process provided by link n in the bit domain wireless multi-hop network for cross real-time services within the time (τ, t), n is the reliability of wireless multi-hop network link n, B is the channel bandwidth, γ n，u is the received signal strength of channel n in time slot u, The priority of wireless link n in the bit domain is p i The arrival process of real-time business, p i 、p j are the priorities of real-time data stream i and real-time data stream j at wireless link n respectively.

[0040] Further, in step S4, an optimization problem of maximizing the number of real-time services transmitted simultaneously in a wireless multi-hop network is formed. Specifically, for a given wireless multi-hop network, an optimization problem is established. When the constraints are met, the goal is to maximize the number of real-time services transmitted simultaneously in the wireless multi-hop network. The optimization problem is expressed as:

[0041]

[0042] stC1:

[0043] C2:

[0044] C3:

[0045] C4:

[0046] C5:

[0047] C6:

[0048] Among them, S l is whether the data flow l is successfully transmitted on the end-to-end path. Constraint 1 means that the data flow l flows through any link e. ij , the link signal to interference and noise ratio SINR ij Must be greater than or equal to the given threshold γ 0 ; Constraint 2 means that data flow l flows through any link e ij , whose sending rate is r l must be less than or equal to the channel capacity of the link, C ij Constraint 3 is the delay constraint, which indicates the actual delay experienced by any data stream l to reach the destination node Must be less than or equal to the deadline Constraint 4 is the jitter constraint, which indicates the actual jitter experienced by any data stream l when reaching the destination node. Must be less than or equal to the jitter threshold Constraint 5 represents the decision variable X l (i, j) is a binary variable; constraint 6 indicates that data flow l is on link e ij Check whether the transmission is successful.

[0049] Furthermore, in step S4, whether the data stream l is successfully transmitted on the end-to-end path is represented by S l :

[0050]

[0051] Where V is the wireless node set of the wireless multi-hop network, X l (i, j) is the decision variable, To represent the data flow l on link e ij Binary variable indicating whether the transfer was successful:

[0052] The beneficial effects of the present invention are as follows: the deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks establishes a performance analysis model for reliable transmission in view of the high time-variability of wireless links, and the analysis results are more in line with the characteristics of wireless multi-hop networks; compared with existing routing decision methods, this method is time-saving and deterministic. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flow chart of a deterministic routing decision method based on real-time performance analysis of a wireless multi-hop network according to an embodiment of the present invention.

[0054] Figure 2 Schematic diagram for explaining a wireless multi-hop network in an embodiment. DETAILED DESCRIPTION

[0055] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0056] Example

[0057] A deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks, such as Figure 1 , including the following steps,

[0058] S1. Collect multiple real-time service flows with different source-destination node pairs generated by terminals at the same time in the wireless multi-hop network, represent them with L = {1, 2, ..., l}, and calculate the wireless link signal-to-interference-to-noise ratio SINR between wireless nodes in the wireless multi-hop network. ij ;

[0059] In step S1, the signal-to-interference-and-noise ratio (SINR) of the wireless link between the wireless nodes is calculated. ij Specifically, in a wireless multi-hop network, the wireless links are independent of each other and all obey Rayleigh fading. Considering the complexity of calculating global interference, only the interference from one-hop neighbor nodes is considered. Then the SINR received at the receiving node j is ij Expressed as:

[0060]

[0061] in, is the received signal strength of receiving node j in time slot t, d ij is the Euclidean distance between wireless node i and wireless node j, α is the path loss exponent, |h ij | is the Rayleigh fading channel gain of the link between wireless node i and wireless node j, which is an exponentially distributed random variable with unit mean. d kj is the Euclidean distance between node k and node j, k∈V; N 0 is the noise power; V j is the set of one-hop neighbor nodes that interfere with wireless node j; |h kj | is the Rayleigh fading channel gain of the link between wireless node k and wireless node j.

[0062] like Figure 2 , the wireless multi-hop network includes multiple wireless nodes indexed as v∈[1,...,V} and several terminals. The wireless nodes are interconnected through multi-hop wireless links. The wireless nodes both generate data and forward data from other nodes. Assume that all wireless nodes have the same transmission power P and the nodes use the communication method specified by the IEEE 802.11 standard (for example, WiFi / Bluetooth). If the link signal interference noise ratio between node i and node j is greater than or equal to the given link signal interference noise ratio threshold γ 0 , then node j is within the communication range of node i. Each terminal has the same QoS requirements. The links in the wireless multi-hop network are independent of each other and all obey Rayleigh fading. Assume that the duration of the real-time service flow is T and the deadline is T d , the time slot length is Δt, Δt = 1ms. Assume that the real-time service flow l passes through N nodes from the source node to the destination node. l Jump wireless link, N l The hop wireless link is called the transmission path of the real-time service flow l and is represented by P l express.

[0063] S2: SINR of the wireless link obtained from step S1 ij , calculate the reliability P of wireless multi-hop network links n , define the link effective service process, according to the wireless multi-hop network link reliability Pn Calculation link effective service process

[0064] In step S2, the wireless link signal to interference and noise ratio SINR obtained in step S1 is ij ,For the reliability of wireless multi-hop network links, specifically, the reliability of the wireless link between node i and node j in the wireless multi-hop network is used to measure the dynamic change of the wireless channel. n , defined as the signal-to-interference-plus-noise ratio (SINR) of the wireless link n between wireless nodes i and j ij Greater than the threshold γ 0 Probability:

[0065]

[0066]

[0067] in, is the received signal strength of receiving node j in time slot t, d ij is the Euclidean distance between node i and node j, α is the path loss exponent, |h ij | is the Rayleigh fading channel gain of the link between node i and node j, which is an exponentially distributed random variable with unit mean. d kj is the Euclidean distance between node k and node j, k∈V; N 0 is the noise power; V j is the set of one-hop neighbor nodes that interfere with node j; |h kj | is the Rayleigh fading channel gain of the link between node k and node j.

[0068] In step S2, a link effective service process is defined. Specifically, the link effective service process is defined as the maximum rate at which a wireless multi-hop network link can transmit under reliable conditions in a certain time slot, and the link effective service process provided by the link n between the wireless node i and the wireless node j within the time (τ, t) for:

[0069]

[0070] in, P represents the link effective service process provided by link n in the exponential domain within the time (τ, t), n represents the reliability of wireless multi-hop network link n, s n (τ, t) represents the maximum rate of link n in the bit-domain wireless multi-hop network within the time (τ, t), B is the channel bandwidth, γ n，u is the received signal strength of channel n in time slot u;

[0071] S3: Link effective service process obtained from step S2 Through the random network calculation method, according to the convolution theorem, the real-time service arrival process is obtained Effective service process provided The closed expression of the relationship between the upper bound of the delay of an N-hop path and the default probability is obtained. Then we get the hop count-delay relationship, and the N-hop real-time service delay threshold w is obtained from the hop count-delay relationship N ;

[0072] S311, on wireless link n, the cumulative arrival process of the cross real-time services of the wireless multi-hop network based on network calculation in time slot t It is expressed as:

[0073]

[0074] in, The priority of wireless link n in the bit domain is p i The arrival process of real-time business, p i 、p j are the priorities of real-time data stream i and real-time data stream j at wireless link n, The priority of wireless link n in the index domain is p i The arrival process of cross-real-time business;

[0075] The sum of the first arriving traffic on link n in time slot t As cross traffic The traffic on link n in time slot t is composed of cross-flow and throughflow The cross flow priority is higher than the through flow priority.

[0076] S312, combining the convolution theorem to obtain link n within the time (τ, t) can be a process that runs through the real-time service arrival process Effective service process provided for:

[0077]

[0078] Among them, s n (τ, t) represents the service process provided by link n in the bit-domain wireless multi-hop network within the time (τ, t), P represents the service process provided by link n in the bit domain wireless multi-hop network for cross real-time services within the time (τ, t),n is the reliability of wireless multi-hop network link n, B is the channel bandwidth, γ n，u is the received signal strength of channel n in time slot u, The priority of wireless link n in the bit domain is p i The arrival process of cross-real-time business, p i 、p j are the priorities of real-time data stream i and real-time data stream j at wireless link n respectively.

[0079] S32: Valid service process obtained from step S31 Derive the end-to-end delay default probability of a real-time data flow passing through an N-hop path

[0080]

[0081] in, is the real-time service delay, w N is the N-hop real-time service delay threshold, e is the exponential value, σ(s) is the arrival rate of the real-time service, σ c (s) is the cross-real-time service arrival rate, ρ(s) is the burst size of the cross-real-time service, ρ c (s) is the burst size of cross real-time services, s is a free parameter, 0<s<1; for ease of expression, let the variable N ≥ 2, let the variable P n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function, V n+1 (s) is the variable V n (s)’s next hop variable, V N (s) is the Nth jump variable;

[0082] In step S32, the effective service process obtained in step S31 Derive the end-to-end delay default probability of a real-time data flow passing through an N-hop path That is, the derivation process of formula (6) is described as follows:

[0083] S321, link effective service process provided by link n within (τ, t) time Mellin transformation for:

[0084]

[0085] in, Valid service process for the link The expectation in (τ, t) time, s is a free parameter, u is the time slot, γ n，u is the received signal strength of channel n in time slot u, P n is the reliability of wireless multi-hop network link n, B is the channel bandwidth, is the signal-to-interference-to-noise ratio of wireless multi-hop network link n, e is the exponential value, y u is a variable, is the upper incomplete gamma function.

[0086] By using the Mellin transformation of the link effective service process provided by link n in (τ, t) time, we can obtain that link n can provide effective service process S for the entire service flow in the exponential domain: o，n Mellin transformation for:

[0087]

[0088] in, is the effective service process that link n can provide, is the cumulative arrival process of cross-link real-time services on link n, is the Mellin transformation of the link effective service process provided by link n in (τ, t) time, is the cumulative arrival process of exponential domain cross real-time services on link n The Mellin transformation, P n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function, σ c (s) is the cross-real-time service arrival rate, ρ(s) is the burst size of the cross-real-time service, and s represents a free parameter. For ease of expression, let the variable

[0089] S322, combining the remainder theorem and the convolution theorem, the wireless multi-hop network links 1, 2, ..., N are the effective service processes S provided throughout the service flow. o，1 , S o，2 ...S o，N Convolution is a single equivalent system that can provide effective service process S throughout the real-time business flow o，net for:

[0090]

[0091] This single equivalent system can provide effective service process S throughout the real-time business flow o，net Mellin transformation for:

[0092]

[0093] in, is the expectation of the effective service process provided by the equivalent system for the real-time business flow within time (τ, t), S o，1 , S o，2 ...S o，N is the wireless multi-hop network link 1, 2, ..., N is the effective service process provided throughout the service flow, s is a free variable, 0<s<1, u 0 ,u 1 ,u 2 ...u N-1 ,u N is the 0th, 1st, 2nd...N-1, Nth time point, u 0 =τ,u N =tu 0 ≤u 1 ≤u 2 ≤…≤u N-1 ≤u N , S o，1 (τ,u 1 ) is the time (τ, u 1 ) The wireless multi-hop network link 1 is an effective service process provided by the service flow, S o，2 (u 2 ,u 3 ) is the time (u 2 ,u 3 ) The wireless multi-hop network link 2 is an effective service process provided by the service flow, S o，N (u N-1 , t) is the time at which N-1 ,t) The wireless multi-hop network link N-1 provides an effective service process for the service flow. For the time (u n-1 ,u n ) The wireless multi-hop network link n provides an effective service process S for the service flow o，n Mellin transformation, e is the exponent value, σ c (s) is the cross real-time service arrival rate, ρ c (s) is the burst size of real-time services. For ease of expression, let the variable v n+1 (s) is the variable V n (s)’s next hop variable, V 1 (s), V N (s) is the 1st and Nth jump variables, P n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function;

[0094] The effective service process S that can be provided by a single equivalent system throughout the real-time business flow o，net Merlin finds that when a real-time data stream passes through an N-hop path, its end-to-end delay default probability is

[0095]

[0096]

[0097] in, is the real-time service delay, w N is the N-hop real-time service delay threshold, is the real-time service arrival process of wireless multi-hop network link 1 exponential domain within time (u, t) The Merlin transformation, is the time (u, t+w N ) within a single equivalent system can provide effective service process S throughout the real-time business flow o，net Mellin transformation, s is a free variable, 0<s<1u 0 u 1 u 2 ...u N-1 ,u N is the 0th, 1st, 2nd...N-1, Nth time point, u 0 =τ,u N =t,u 0 ≤u 1 ≤u 2 ≤…≤u N-1 ≤u N , e is the exponential value, v is the moment value, σ c (s) is the cross real-time service arrival rate, ρ c (s) is the burst size of real-time services, σ(s) is the arrival rate of real-time services, and ρ(s) is the burst size of real-time services. For ease of expression, let the variable V n+1 (s) is the variable V n (s)’s next hop variable, V 1 (s), V N (s) is the 1st and Nth jump variables, P n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function. For ease of expression, let the variable

[0098] Let the right side of inequality (10) be equal to the constant c:

[0099]

[0100] Among them, w N is the N-hop real-time service delay threshold, e is the exponential value, σ(s) is the arrival rate of the real-time service, σ c (s) is the cross real-time service arrival rate, s is a free parameter, 0<s<1; for ease of expression, let the variable N≥2, ρ(s) is the burst size of real-time services, ρ c (s) is the burst size of cross real-time services, let the variable v n+1 (s) is the variable V n (s)’s next hop variable, V N (s) is the Nth jump variable, p n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function;

[0101] S33. The relationship between the number of hops and the delay when the real-time data stream passes through an N-hop end-to-end path is:

[0102]

[0103] Among them, w N is the N-hop real-time service delay threshold, s is a free parameter, 0<s<1, σ(s) is the arrival rate of real-time services, the constant c represents the fixed value of the end-to-end delay default probability, σ c (s) is the cross-real-time service arrival rate, ρ(s) is the burst size of the cross-real-time service; for ease of expression, let the variable Let the variable N ≥ 2, ρ c (s) is the burst size of cross real-time services, let the variable v n+1 (s) is the variable V n (s)’s next hop variable, V N (s) is the Nth jump variable, p n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function;

[0104] S4, considering the delay, capacity and reliability constraints, forming an optimization problem of maximizing the number of real-time services transmitted simultaneously in a wireless multi-hop network;

[0105] In step S4, an optimization problem of maximizing the number of real-time services transmitted simultaneously in a wireless multi-hop network is formed. Specifically, for a given wireless multi-hop network, an optimization problem is established. When the constraints are met, the goal is to maximize the number of real-time services transmitted simultaneously in the wireless multi-hop network. The optimization problem is expressed as:

[0106]

[0107] stC1:

[0108] C2:

[0109] C3:

[0110] C4:

[0111] C5:

[0112] C6:

[0113] Among them, constraint 1 means that data flow l flows through any link e ij , the link signal to interference and noise ratio SINR ij Must be greater than or equal to the given threshold γ 0 ;

[0114] Constraint 2 means that data flow l flows through any link e ij , whose sending rate is r l must be less than or equal to the channel capacity of the link, C ij .

[0115] At time slot t, the effective link capacity C between node i and node j ij (t) is expressed as: Assign a decision variable X to each data stream l , l∈{1, 2, ..., L}, there are L decision variables for L real-time streams, for example, the decision variable of real-time stream 1 is X 1 , then X 1 (i, j) = 1 means that real-time stream 1 flows through link e ij .

[0116] At time slot t, for all real-time flows passing through adjacent nodes i and j, the capacity constraint that must be satisfied is:

[0117]

[0118] in, is the required transmission rate of real-time stream l from node i to node j.

[0119] Constraint 3 is the delay constraint, which means that for any data flow l, the actual delay experienced by reaching the destination node must be less than or equal to the deadline

[0120] The end-to-end delay of real-time services in wireless multi-hop networks consists of two parts: the delay caused by queuing at the node when the real-time service is transmitted and the delay required for the real-time service to be fully transmitted at the node. Therefore, the end-to-end delay of real-time services is calculated as follows: in, Indicates the actual delay experienced by the end-to-end transmission of the real-time stream l; represents the queuing delay experienced by the end-to-end transmission of the real-time stream l; Indicates the transmission delay experienced by the real-time stream l for end-to-end transmission. In order to ensure the strict requirement of low delay for any data stream, the delay generated by the real-time stream l through the end-to-end path must meet the following requirements: in, is the deadline of the real-time data stream l.

[0121] Constraint 4 is the jitter constraint, which means that for any data stream l, the actual jitter experienced when reaching the destination node must be less than or equal to the jitter threshold.

[0122] In a wireless multi-hop network, the jitter generated by the real-time data stream l after multi-hop transmission is equivalent to the jitter accumulated in the last hop, that is, the jitter generated by the real-time stream l on the end-to-end path can be expressed as: in, is the deadline of the real-time data stream l, It represents the actual delay experienced by the end-to-end transmission of the real-time stream l. In order to ensure the strict requirement of low jitter for any data stream, the jitter generated by the real-time stream l through the end-to-end path must meet the following requirements: in, is the jitter upper limit of the real-time data stream l.

[0123] Constraint 5 represents the decision variable X l (i, j) is a binary variable.

[0124] Constraint 6 indicates that data flow l on link e ij Check whether the transmission is successful.

[0125] In step S4, whether the data stream l is successfully transmitted on the end-to-end path is represented by S l :

[0126]

[0127] Where V is the set of wireless nodes in the wireless multi-hop network, To represent the data flow l on link e ij Binary variable indicating whether the transfer was successful: l∈{1, 2, ..., L}.

[0128] S5. The real-time service delay threshold corresponding to each hop value obtained in step S3 excludes the path that exceeds the maximum real-time service delay, and obtains K shortest paths that meet the delay, capacity and reliability constraints of step S4 based on K-shortest paths;

[0129] S6. Search the K shortest paths determined in step S5 by exhaustive method to solve the optimization problem and obtain the optimal path.

[0130] This deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks establishes a performance analysis model for reliable transmission in view of the high time-varying nature of wireless links. The analysis results are more in line with the characteristics of wireless multi-hop networks. Compared with existing routing decision methods, this method is time-saving and deterministic.

[0131] This deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks introduces wireless multi-hop network link reliability analysis in view of the highly time-varying characteristics of wireless multi-hop network channels, making the end-to-end performance analysis of wireless multi-hop network real-time services more comprehensive. In view of the dynamic change characteristics of wireless links, an effective service process is introduced, and a performance analysis model of multi-hop end-to-end paths is established through the effective service process. The optimal path that maximizes the number of real-time services transmitted simultaneously in the wireless multi-hop network is solved according to the analysis model, thereby effectively solving the deterministic routing problem of real-time services in wireless multi-hop networks.

[0132] This deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks establishes a performance analysis model for reliable transmission in view of the highly time-varying characteristics of wireless multi-hop network channels, and formulates and solves the problem of maximizing the number of real-time services transmitted simultaneously in wireless multi-hop networks based on this model. This method first obtains a closed expression for the relationship between the upper bound of the delay and the probability of default of real-time services in wireless multi-hop networks based on the random network calculation method combined with the reliable service process provided by the wireless link, and derives the hop count-delay relationship. Then a deterministic path search algorithm is proposed, which solves the problem of maximizing the number of real-time services transmitted simultaneously in wireless multi-hop networks by reducing the initial path set based on the K-shortest path. This method can obtain the optimal path more efficiently by considering more comprehensive factors in the performance analysis of wireless multi-hop networks.

[0133] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks, characterized in that: The following steps are included: S1. Collect multiple real-time service flows with different source-destination node pairs generated by terminals at the same time in the wireless multi-hop network, and calculate the wireless link signal-to-interference-to-noise ratio (SINR) between wireless node i and wireless node j in the wireless multi-hop network. ij ; S2: SINR of the wireless link obtained from step S1 ij , calculate the link reliability P n , define the link effective service process, and according to the link reliability P n Calculate the link effective service process provided by link n between wireless node i and wireless node j within (τ, t) time S3: Link effective service process obtained from step S2 Through the random network calculation method, according to the convolution theorem, the real-time service arrival process is obtained Effective service process provided The closed expression of the relationship between the upper bound of the delay of an N-hop path and the default probability is obtained. in, is the real-time service delay, and then the hop count-delay relationship is obtained. The N-hop real-time service delay threshold w is obtained from the hop count-delay relationship N ; S4, considering the delay, capacity and reliability constraints, forming an optimization problem of maximizing the number of real-time services transmitted simultaneously in a wireless multi-hop network; S5. The real-time service delay threshold corresponding to each hop value obtained in step S3 excludes the path that exceeds the maximum real-time service delay, and obtains K shortest paths that meet the delay, capacity and reliability constraints of step S4 based on K-shortest paths; S6. Search the K shortest paths determined in step S5 by exhaustive method to solve the optimization problem of maximizing the number of real-time services transmitted simultaneously in the wireless multi-hop network and obtain the optimal path.

2. The deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks according to claim 1, characterized in that: In step S1, the signal-to-interference-plus-noise ratio (SINR) of the wireless link between wireless nodes is calculated. ij Specifically, in a wireless multi-hop network, the wireless links are independent of each other and all obey Rayleigh fading. Considering the complexity of calculating global interference, only the interference from one-hop neighbor nodes is considered. Then the SINR received at the receiving node j is ij It is expressed as: in, is the received signal strength of wireless node j in time slot t, d ij ,d kj are the Euclidean distances between wireless nodes i and j, and between wireless nodes k and j, respectively. α is the path loss index. ij |、|h kj | are the Rayleigh fading channel gains of the link between wireless node i and wireless node j, and the link between wireless node k and wireless node j, respectively; N0 is the noise power; V j is the set of one-hop neighbor nodes that interfere with wireless node j.

3. The deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks as claimed in claim 1, characterized in that: In step S2, the wireless link signal to interference and noise ratio SINR obtained in step S1 is ij , the reliability of wireless multi-hop network links is analyzed. Specifically, the reliability of link n in the wireless multi-hop network is P n , defined as the signal-to-interference-plus-noise ratio (SINR) of the wireless link n between wireless nodes i and j ij The probability of being greater than the threshold γ0: in, is the received signal strength of wireless node j in time slot t, d ij ,d kj are the Euclidean distances between wireless nodes i and j, and between wireless nodes k and j, respectively. α is the path loss index. ij |、|h kj | are the Rayleigh fading channel gains of the link between wireless node i and wireless node j, and the link between wireless node k and wireless node j, respectively; N0 is the noise power; V j is the set of one-hop neighbor nodes that interfere with wireless node j.

4. The deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks according to any one of claims 1 to 3, characterized in that: In step S2, a link effective service process is defined. Specifically, the link effective service process is defined as the maximum rate at which a wireless multi-hop network link can transmit under reliable conditions in a certain time slot, and the link effective service process provided by the link n between the wireless node i and the wireless node j within the time (τ, t) for: in, P represents the link effective service process provided by link n in the exponential domain within the time (τ, t), n represents the reliability of wireless multi-hop network link n, s n (τ, t) represents the maximum rate of link n in the bit-domain wireless multi-hop network within the time (τ, t), B is the channel bandwidth, γ n，u is the received signal strength of channel n in time slot u.

5. The deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks according to any one of claims 1 to 3, characterized in that: In step S3, a random network calculation method based on the link effective service process is used to obtain the real-time service arrival process according to the convolution theorem. Effective service process provided The closed expression of the relationship between the upper bound of the real-time service delay and the default probability is obtained, and then the hop count-delay relationship is obtained, which is: S31. Based on network calculation, the cumulative arrival process of cross-real-time services in the wireless multi-hop network is obtained within the time (τ, t) on the wireless link n. Combined with the convolution theorem, we can get Effective service process provided S32: Valid service process obtained from step S31 Derive the end-to-end delay default probability of a real-time data stream passing through an N-hop path in, is the real-time service delay, w N is the N-hop real-time service delay threshold, e is the exponential value, σ(s) is the arrival rate of the real-time service, σ c (s) is the cross-real-time service arrival rate, ρ(s) is the burst size of the cross-real-time service, ρ c (s) is the burst size of cross real-time services, s is a free parameter, 0<s<1; for ease of expression, let the variable N ≥ 2, let the variable P n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function, V n+1 (s) is the variable V n (s)’s next hop variable, V N (s) is the Nth jump variable; S33, let the right side of formula (6) obtained in step S32 be equal to constant c, and then obtain the relationship between the number of hops and the delay when the real-time data flow passes through an N-hop end-to-end path: Among them, w N is the N-hop real-time service delay threshold, S is a free parameter, 0<s<1, σ(s) is the arrival rate of the real-time service, σ c (s) is the cross-real-time service arrival rate, ρ(s) is the burst size of the cross-real-time service, and for ease of expression, let the variable Let the variable N ≥ 2, ρ c (s) is the burst size of cross real-time services, let the variable V n+1 (s) is the variable V n (s)’s next hop variable, V N (s) is the Nth jump variable, P n represents the reliability of wireless multi-hop network link n, B is the channel bandwidth, It represents the signal-to-interference-to-noise ratio value of wireless multi-hop network link n, e is the exponential value, is the upper incomplete gamma function.

6. The deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks as claimed in claim 5, characterized in that: In step S31, a random network calculation method based on the link effective service process is used to obtain the real-time service arrival process according to the convolution theorem. Effective service process provided Specifically, S311, within the time (τ, t) on the wireless link n, based on network calculation, the cumulative arrival process of the cross real-time services in the wireless multi-hop network is obtained It is expressed as: in, The priority of wireless link n in the bit domain is p i The arrival process of real-time business, p i 、p j are the priorities of real-time data stream i and real-time data stream j at wireless link n, The priority of wireless link n in the index domain is p i The arrival process of cross-real-time business; S312, combined with the convolution theorem, it is obtained that link n can be a real-time service arrival process within the time (τ, t) Effective service process provided for: Among them, S n (τ, t) represents the service process provided by link n in the bit-domain wireless multi-hop network within the time (τ, t), represents the service process provided by link n in the bit-domain wireless multi-hop network for cross-link real-time services within the time (τ, t), P n is the reliability of wireless multi-hop network link n, B is the channel bandwidth, γ n，u is the received signal strength of channel n in time slot u, The priority of wireless link n in the bit domain is p i The arrival process of cross-real-time business, p i 、p j are the priorities of real-time data stream i and real-time data stream j at wireless link n respectively.

7. The deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks according to any one of claims 1 to 3, characterized in that: In step S4, an optimization problem of maximizing the number of real-time services transmitted simultaneously in a wireless multi-hop network is formed. Specifically, for a given wireless multi-hop network, an optimization problem is established. When the constraints are met, the goal is to maximize the number of real-time services transmitted simultaneously in the wireless multi-hop network. The optimization problem is expressed as: Among them, S l is whether the data flow l is successfully transmitted on the end-to-end path. Constraint 1 means that the data flow l flows through any link e. ij , the link signal to interference and noise ratio SINR ij must be greater than or equal to a given threshold γ0; Constraint 2 indicates that data flow l flows through any link e ij , whose sending rate is r l must be less than or equal to the channel capacity of the link, C ij Constraint 3 is the delay constraint, which indicates the actual delay experienced by any data stream l to reach the destination node Must be less than or equal to the deadline Constraint 4 is the jitter constraint, which indicates the actual jitter experienced by any data stream l when reaching the destination node. Must be less than or equal to the jitter threshold Constraint 5 represents the decision variable X l (i, j) is a binary variable; constraint 6 indicates that data flow l is on link e ij Check whether the transmission is successful.

8. The deterministic routing decision method based on real-time performance analysis of wireless multi-hop networks as claimed in claim 7, characterized in that: In step S4, whether the data stream l is successfully transmitted on the end-to-end path is represented by S l : Where V is the wireless node set of the wireless multi-hop network, X l (i, j) is the decision variable, To represent the data flow l on link e ij Binary variable indicating whether the transfer was successful:

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