CN115801380A - Satellite Internet of things system and method for resisting networking uplink interference attack - Google Patents

Abstract

The invention discloses a satellite Internet of things system and a method for resisting networking uplink interference attack, wherein the satellite Internet of things system comprises: a central gateway, a plurality of service areas and space segments; the service area includes a plurality of legitimate terminal nodes and the segment of space is comprised of one or more communication satellites in geostationary or non-geostationary orbit. Each communication satellite provides a single or multiple beams to cover different service areas, and the satellite can connect the service areas to a central gateway, and then store and transmit the collected messages to the central gateway. The method comprises the following steps: and calculating the load G of the MAC layer, calculating the lead time, calculating the average data packet arrival number, and calculating the minimum IC step length under the appointed detection probability through Poisson distribution. The invention has the advantages that: the system performance reduction caused by lead code disguise attack can be resisted, lead code deception interference which greatly influences the system performance is effectively eliminated, and the system stability is greatly improved.

Description

Satellite Internet of things system and method for resisting networking uplink interference attack

Technical Field

The invention relates to the technical field of satellite Internet of things, in particular to a satellite Internet of things and a method for resisting network camouflage interference attack by using a lead code deception receiver.

Background

The increasing demand for IoT (internet of things) in various applications has been a great impetus for many technical fields of research, development and innovation in recent years. The growth rate of the number of connected devices is expected to continue to rise, and the use of connection density satellite networks that will reach 1000 tens of thousands of devices per square kilometer by 2030 is considered a natural solution to expand the service area of the internet of things in a cost attractive and performance manner.

Satellite internet of things networks provide remote access to a large number of devices while maintaining low access control overhead. In other words, the satellite network can grant access to the user without pre-allocating capacity for each connection. This scheme, also known as random access, reduces the signaling exchange requirements between a single node (remote device) and a gateway (satellite or ground station).

The air interface S-MIM protocol of satellite ground station and system (SES) S band mobile interactive multimedia (S-MIM) has been followed, and its use cases have been commercially deployed to provide internet tv and M2M services, and in addition to commercial deployment, the S-MIM air interface uses a spread spectrum scheme that is resilient to the inherent interference of the constant radio uplink channel, but the threat may be more serious when the air interface is used externally, especially for interference attacks with knowledge of the relevant protocols of the physical and access layers.

Disclosure of Invention

The invention provides a satellite internet of things and a method for resisting internet uplink interference attack, aiming at the technical problem that the performance of a system is reduced because the uplink of the current satellite internet of things is easily interfered by lead code deception, so that the stability of a ground station receiving system is enhanced.

In order to realize the purpose, the technical scheme adopted by the invention is as follows:

a satellite internet of things system, comprising: a central gateway, a plurality of service areas and space segments;

the service area comprises a plurality of legal terminal nodes, and the terminal nodes comprise Internet of things equipment and interference equipment. The space segment is comprised of one or more communication satellites in geostationary or non-geostationary orbit. Each communication satellite provides a single or multiple beams to cover different service areas as multiple cells. A two-way communication link between the satellite and each service area is provided to broadcast a common message to all end nodes and to collect messages from the end nodes themselves using a random access direct channel. Each satellite can operate transparently to connect the service area to the central gateway or implement an onboard communication protocol, then store the collected messages and transmit them to the central gateway.

The invention also discloses a method for resisting the uplink interference attack of the satellite Internet of things, which is realized based on the main subsystem of the satellite Internet of things, provides an interference elimination step length for a receiver through a receiving end of the uplink of the satellite Internet of things system, and comprises the following steps:

s101: the MAC layer load G is calculated. Systems affected by significant interference are identified by obtaining a value for the MAC load G, the greater the value of G, the greater the interference experienced by the system.

S102: the preamble time is calculated. The receiver operation is characterized by a continuous search for valid preambles over the scanning window, and the preamble search is followed by the required data detection before IC (interference cancellation).

S103: the average packet arrival number is calculated. To limit the complexity of the IC, the receiver typically limits the IC step size, but if the maximum value of the IC step size is too small, several packets may not be detected, resulting in an associated loss of received data. Depending on the number of expected packets in the observation window.

S104: and calculating the minimum IC step size under the specified detection probability through Poisson distribution.

Further, step S101 specifically includes: setting the time T corresponding to the data packet generated by the random Poisson process with the number of 10 millisecond frames contained in the uplink burst structure after the lead code and the strength of lambda packet/s _pk Where k represents the kth packet, the MAC load is given by the following equation:

wherein: g is MAC layer load, R _c Is the symbol rate, SF is the spreading factor, and DBL is the data burst length.

Further, step S102 specifically includes:

the TFI in ESS-se:Sup>A specifies se:Sup>A preamble of 12 bytes, se:Sup>A fixed number equal to 96, se:Sup>A preamble time of:

further, step S103 specifically includes:

equal to one preamble time T in duration _pr The average packet arrival number during the observation window of (1) is:

further, step S104 specifically includes:

despite mean value

Given a valid indication of the number of IC steps required, but requiring a more elaborate analysis to evaluate the actual number of IC steps required to detect all data packet preambles in the observation window, the poisson distribution is calculated as:

where k is the number of preamble symbols in the observation window, P _k Indicating the probability of arrival of the kth packet.

Assuming that the acceptable probability of missed detection is epsilon, the minimum IC step size required to detect all packet preambles with a probability greater than 1-epsilon is calculated as follows:

compared with the prior art, the invention has the advantages that:

the model is based on the ETSI S-MIM standard, and assumes that an attacker carries out interference attack through an ESS-A access protocol, introduces se:Sup>A random Poisson process to describe the arrival strength and load of random datse:Sup>A packets in an uplink, and calculates the actual interference elimination step length required for detecting all datse:Sup>A packet preambles in an observation window. Therefore, the receiving system can resist the system performance reduction caused by the lead code disguise attack, lead code deception interference which greatly influences the system performance is effectively eliminated, and the system stability is greatly improved.

Drawings

Fig. 1 is a schematic diagram of a system architecture of a satellite internet of things according to an embodiment of the invention;

FIG. 2 is a flow chart of the E-SSA protocol main operation loop according to the embodiment of the present invention;

FIG. 3 is a schematic diagram of a sequential detection loop of the E-SSA protocol according to an embodiment of the present invention;

fig. 4 is a flowchart of a method for defending against an uplink interference attack of a satellite internet of things according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below by referring to the accompanying drawings and embodiments.

As shown in fig. 1, a satellite internet of things main subsystem architecture based on which a method for defending against uplink interference attack of a satellite internet of things includes:

the system includes a Gateway (Gateway) and a plurality of service areas, including a large number of legitimate Internet of things Devices (Iot Devices) and possibly some jamming Devices (Jammer Devices). A segment of space may be comprised of one or more Communication satellites (satellites) in geostationary or non-geostationary orbit. Each satellite provides a single or multiple beams to cover different geographic Service Areas as multiple cells (Service Areas). It is assumed that the two-way communication link between the satellite and each service area broadcasts a common message to all end nodes and collects the message from the nodes themselves using a random access direct channel. Each satellite may operate transparently to connect the service area to a terrestrial central gateway, or may implement an onboard communication protocol (e.g., as a regeneration payload) and then store and transmit the collected messages to the central gateway.

As shown in fig. 2, the E-SSA access protocol main operation loop flow based on which the proposed method for defending the uplink interference attack of the satellite internet of things explains the specific flows of the receiver capturing data and eliminating interference in detail:

the received signal is described by the following equation:

in the formula (1), gamma _i Gain of uplink channel (terminal to satellite), tau, corresponding to the ith Internet of things terminal _i For corresponding time delays, s _i (t) is the signal transmitted by the terminal, and z (t) is the satellite receiver noise. Each transmission signal of an internet of things node comprises a preamble (common to all nodes) and a data field (specific to the node), which can be expressed as follows:

thus, T _p Represents the time span of the preamble, and T _d Representing the time span of the data block. To synchronize the preamble of a particular user, the received signal is passed through a receiver with an impulse response p (-t) ^* The output of the correlation filter of (1) is as follows:

successive samples to estimate time delay tau _i . Each with a specific delay phase as long as the detection is in progressThe corresponding data packet is reconstructed and subtracted from the received signal by the IC process.

As shown in fig. 3, on the time axis, the receiver operation is characterized by a continuous search for a valid preamble over the scanning window, followed by the data detection required by the IC. In summary, the receiver operation is described as follows:

(1) Within the scanning window, the preamble is continuously scanned and attempted to be detected.

(2) If a preamble is detected, the receiver waits to receive the entire content of the data portion to check its validity (by using a CRC).

(3) If a valid packet is found, its contribution is removed from the received signal and the preamble scan is restarted. This means that the scanning window is completely processed after the complete duration of one data packet (preamble and data field).

As shown in fig. 4, the interference cancellation step size selection procedure includes:

step 1: calculating MAC layer load

The step size of the IC to be performed at the receiver depends on the number of preambles lying in the observation window. This in turn depends on the MAC layer load G and the TFI (transport format indication) under consideration. The latter being dependent on R _c (symbol rate), SF (spreading factor) and DBL (data burst length), i.e. the number of 10ms frames contained in the uplink burst structure after the preamble. Suppose a packet to be generated according to a random poisson process with an intensity of λ packets/s and a time T _pk A packet denoted by = DBL × 10ms, where k denotes the kth packet, the MAC load may be obtained as follows:

step 2: calculating a preamble time

Since the TFI in ESS-se:Sup>A specifies se:Sup>A preamble of 12 bytes, the number is fixed and equal to 96, the preamble time is:

and step 3: calculating average packet arrival number

Equal to one preamble time T in duration _pr The average packet arrival number during the observation window of (1) is:

and 4, step 4: calculating minimum IC step length under specified detection probability through Poisson distribution

Despite mean value

Giving a valid indication of the number of IC steps required, but a more refined analysis is required to evaluate the actual number of IC steps required to detect all data packet preambles in the observation window, depending on the poisson distribution

Where k is the number of preamble symbols in the observation window.

Let the acceptable probability of missed detection be epsilon and the minimum IC step size required to detect all grouped lead codes with probability greater than 1-epsilon be

The above-described method of the present invention can be implemented in hardware, firmware, or as software or computer code that can be stored in a recording medium such as a CD ROM, RAM, floppy disk, hard disk, or magneto-optical disk, or as computer code originally stored in a remote recording medium or a non-transitory machine readable medium and to be stored in a local recording medium downloaded through a network, so that the method described herein can be stored in such software processing on a recording medium using a general purpose computer, a dedicated processor, or programmable or dedicated hardware such as an ASIC or FPGA. It will be appreciated that the computer, processor, microprocessor controller or programmable hardware includes memory components (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code that, when accessed and executed by the computer, processor or hardware, implements the processing methods described herein. Further, when a general-purpose computer accesses code for implementing the processes shown herein, execution of the code transforms the general-purpose computer into a special-purpose computer for performing the processes shown herein.

It will be appreciated by those of ordinary skill in the art that the examples described herein are intended to assist the reader in understanding the manner in which the invention is practiced, and it is to be understood that the scope of the invention is not limited to such specifically recited statements and examples. Those skilled in the art can make various other specific changes and combinations based on the teachings of the present invention without departing from the spirit of the invention, and these changes and combinations are within the scope of the invention.

Claims (6)

1. A satellite internet of things system, comprising: a central gateway, a plurality of service areas and space segments;

the service area comprises a plurality of legal terminal nodes, and the terminal nodes comprise Internet of things equipment and interference equipment; the space segment is composed of one or more communication satellites in geostationary or non-geostationary orbit; each communication satellite providing a single or multiple beams to cover different service areas as multiple cells; setting a two-way communication link between the satellite and each service area to broadcast a common message to all terminal nodes and using a random access direct channel to collect messages from the terminal nodes themselves; each satellite can operate transparently to connect the service area to the central gateway or implement an onboard communication protocol, then store the collected messages and transmit them to the central gateway.

2. A method for resisting uplink interference attack of a satellite Internet of things is characterized by comprising the following steps: the method for resisting the uplink interference attack of the satellite internet of things is realized on the basis of the satellite internet of things system as claimed in claim 1, and comprises the following steps:

s101: calculating the load G of the MAC layer; identifying a system affected by the significant interference by obtaining a value of the MAC load G, wherein the larger the value of G is, the larger the interference on the system is;

s102: calculating a lead time; continuously searching effective lead codes, and carrying out data detection required before interference elimination IC after the lead codes are searched;

s103: calculating the average data packet arrival number; limiting the IC step size, but if the maximum value of the IC step size is too small, the IC step size depends on the expected number of packets in the observation window;

s104: and calculating the minimum IC step size under the specified detection probability through Poisson distribution.

3. The method of claim 1, wherein the method comprises: step S101 specifically includes: setting the time T corresponding to the data packet generated by the random Poisson process with the number of 10 millisecond frames contained in the uplink burst structure after the lead code and the strength of lambda packet/s _pk Where k represents the kth packet, the MAC load is given by the following equation:

wherein: g is MAC layer load, R _c Is the symbol rate, SF is the spreading factor, and DBL is the data burst length.

4. The method of claim 1, wherein the method further comprises: step S102 specifically includes:

the TFI in ESS-se:Sup>A specifies se:Sup>A preamble of 12 bytes, se:Sup>A fixed number equal to 96, se:Sup>A preamble time of:

5. the method of claim 1, wherein the method further comprises: step S103 specifically includes:

equal to one preamble time T in duration _pr The average packet arrival number during the observation window of (1) is:

6. the method of claim 1, wherein the method further comprises: step S104 specifically includes:

despite mean value

Given a valid indication of the number of IC steps required, but requiring a more refined analysis to evaluate the actual number of IC steps required to detect all data packet preambles within the observation window, the poisson distribution is calculated as:

where k is the number of preamble symbols in the observation window, P _k Representing the arrival probability of the kth data packet;

assuming that the acceptable probability of missed detection is epsilon, the minimum IC step size required to detect all packet preambles with a probability greater than 1-epsilon is calculated as follows:

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