Multi-mode channel self-organizing elastic access method

Abstract

The invention discloses a multimode channel self-organizing elastic access method, which comprises the following steps of: firstly, determining an idle channel through channel spectrum sensing, then, obtaining an optimal available channel for transmitting data by using each service through channel quality evaluation, and finally, selecting a corresponding channel to carry out signal transmission according to different service transmission requirements. According to the multimode channel self-organizing elastic access method provided by the invention, elastic self-organizing access of a narrow-band voice service, a broadband binary data communication service and a specific marine safety information communication service is realized, and the optimal communication efficiency is achieved. Meanwhile, by reasonably distributing the data channels, effective spectrum resources are utilized to the maximum extent, and the channel management capacity of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ship communications, and in particular to a multi-mode channel self-organizing elastic access method. Background Art

[0002] The Very High Frequency Data Exchange System (VDES) is a reinforcement and upgrade of the Automatic Identification System (AIS) of the existing marine aids to navigation system. In order to solve the high link load problem caused by the increase in AIS users and the expansion of its applications, VDES has added special application messages (ASM) and very high frequency data exchange (VDE) functions on the basis of integrating the existing AIS services. Among them, the AIS subsystem is used to exchange ship position and speed information, ensure position tracking, route navigation, ship identity identification and other information related to ship route safety, and has the highest priority; ASM is designed to reduce the load of the AIS link and is used to transmit information such as water patterns and weather forecasts; VDE channels are the core of VDES, providing the system with large-capacity data exchange for transmitting information such as nautical charts. The number of VDES communication channels has increased from 2 to 18, with a maximum data rate of 307.2kbps, which has comprehensively improved the data communication capabilities of ships on the water.

[0003] For narrowband voice services, they can be transmitted on VHF voice communication channels, with a total of 75 available channels. Among them, channel 70 (156.525MHz) is a digital selective calling channel for distress, safety and calling, and channel 16 (156.800MHz) is a distress, safety and calling channel. The above dual channels need to be on duty for a long time and cannot be occupied. The new generation of maritime navigation safety communication system can select the best VHF voice communication channel when it is idle.

[0004] For broadband binary data communication services, in view of the radio regulations that the use of maritime navigation safety communication systems should not affect the existing operating frequencies, the maritime frequency band is selected as the frequency that has not yet been allocated to specific business functions, and the channel bandwidth is 300kHz.

[0005] For specific maritime safety information communication services, AIS / ASM / VDE channels can be used. AIS is allocated 4 international channels: two ground AIS channels and two channels for long-distance satellite reception and monitoring of AIS; ASM is allocated 2 international channels: ASM1 and ASM2; VDE is allocated 12 international channels: 6 VDE transmission channels and 6 VDE broadband reception and transmission channels.

[0006] Currently, the commonly used channel sharing technologies include random access, controlled access and channel multiplexing. Random access means that all users can randomly send information to the channel according to their own wishes. When two or more users send information on the shared channel, conflicts will occur; controlled access means that each user cannot access the channel at will but must obey certain controls; channel multiplexing means that multiple low-speed signals are combined into a high-speed signal and transmitted on a high-speed channel. At present, it is necessary to solve the problem of effectively allocating the resources of the above channels to improve the efficiency of channel utilization. Summary of the invention

[0007] To solve the above problems, the present invention provides a multi-mode channel self-organizing elastic access method, the specific scheme is as follows:

[0008] A multi-mode channel self-organizing elastic access method, the method comprising the following steps:

[0009] S1. Determine idle channels through channel spectrum sensing

[0010] S1-1. A binary hypothesis test model is used as a theoretical model for channel spectrum sensing. The received signal is filtered by bandpass filtering, high-frequency and low-frequency noise and interference signals are filtered, and only valid signals within the frequency band to be detected are retained. The valid signals are sampled to obtain discrete signals.

[0011] S1-2, obtain the signal energy of each channel by obtaining the discretized signal, and determine whether there is a signal in the channel according to the set threshold.

[0012] If the signal exists, the channel cannot be used;

[0013] If the signal does not exist, the channel is an idle channel and is used as a backup channel to send data.

[0014] S2. Obtain the best available channel for data transmission of each service through channel quality assessment

[0015] The receiving station reports a signal-to-noise-plus-interference ratio in the relevant response message, and estimates the channel quality indicator based on the estimated value of the signal-to-noise-plus-interference ratio;

[0016] The channel quality index is an integer, occupies one byte, and ranges from 0 to 255;

[0017] The larger the channel quality index value is, the better the channel quality is;

[0018] The accuracy of the channel quality indicator parameter is 0.25dB;

[0019] When the estimated signal-to-noise ratio plus interference ratio is less than -10.0dB, the minimum value of the channel quality index is 0;

[0020] When the estimated signal-to-noise plus interference ratio is greater than 53.75 dB, the maximum channel quality index is 255;

[0021] The channel with the largest channel quality index is selected from the idle channels of each service as the candidate channel for the next data transmission.

[0022] S3. Select the corresponding channel for signal transmission according to different business transmission requirements

[0023] The services include narrowband voice services, broadband binary data communication services, and specific maritime safety information communication services;

[0024] The narrowband voice service selects the best channel for transmission among 75 VHF voice communication channels;

[0025] The broadband binary data communication service selects the best channel for transmission from channels to which no specific service functions are allocated;

[0026] The specific maritime safety information communication service selects the optimal channel for transmission among the AIS / ASM / VDE channels.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Realize flexible self-organizing access to narrowband voice services, broadband binary data communication services, and specific maritime safety information communication services to achieve optimal communication efficiency.

[0029] (2) Reasonably allocate data channels to maximize the use of effective spectrum resources and improve the system's channel management capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions disclosed in the present invention, the following briefly introduces the drawings required to be used in some embodiments disclosed in the present invention. Obviously, the drawings described below are only drawings of some embodiments disclosed in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the products involved in the embodiments disclosed in the present invention, the actual process of the method, etc.

[0031] Figure 1 It is a flow chart of the multi-mode channel self-organizing elastic access method provided by the present invention.

[0032] Reference numerals: AIS, Automatic Identification System; VDE, Very High Frequency Data Exchange; ASM, Application Specific Message. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] like Figure 1 The flowchart of the multi-mode channel self-organizing elastic access method provided by the present invention includes the following steps:

[0035] S1. Determine idle channels through channel spectrum sensing

[0036] S1-1. The binary hypothesis test model is used as the theoretical model of channel spectrum perception. The received signal is filtered by bandpass filtering, filtering out high-frequency and low-frequency noise and interference signals, and only the valid signal y(t) in the frequency band to be detected is retained. The valid signal y(t) is sampled to obtain the discrete signal: y = (y1, y2, L y N );

[0037] The binary hypothesis testing model is:

[0038]

[0039] Where r(t) represents the received signal, n(t) represents the noise signal, s(t) represents the transmitted signal, H0 represents that there is no signal in the channel, and H1 represents that there is a signal in the channel;

[0040] S1-2. Obtain the signal energy of each channel by obtaining the discretized signal, and determine whether there is a signal in the channel according to the set threshold ξ. The definition of the decision statistic λ of spectrum sensing is as follows:

[0041]

[0042] When λ≥ξ, there is a signal in the channel and the channel cannot be used;

[0043] When λ<ξ, the channel is an idle channel and is used as a backup channel to send data.

[0044] S2. Obtain the best available channel for data transmission of each service through channel quality assessment

[0045] S2-1, the receiving station reports a signal-to-noise-plus-interference ratio in the relevant response message, and estimates the channel quality indicator based on the estimated value of the signal-to-noise-plus-interference ratio;

[0046] The relationship between the signal-to-noise ratio plus interference ratio SNIR and the channel quality indicator CQI is as follows:

[0047] CQI=40+4SNIR

[0048] The channel quality indicator CQI is an integer, occupies one byte, and ranges from 0 to 255; the larger the channel quality indicator CQI value, the better the channel quality;

[0049] The accuracy of the channel quality indicator CQI parameter is 0.25dB;

[0050] When there is no interference, SNIR is equal to the signal-to-noise ratio on an additive white Gaussian noise channel (AWGN);

[0051] When the estimated SNIR value is less than -10.0dB, the minimum value of CQI is 0;

[0052] When the estimated SNIR value is greater than 53.75 dB, the maximum CQI is 255.

[0053] S2-2. Select a channel with the largest channel quality index from the idle channels of each service as a candidate channel for subsequent data transmission.

[0054] S3. Select the corresponding channel for signal transmission according to different business transmission requirements

[0055] The services include narrowband voice services, broadband binary data communication services, and specific maritime safety information communication services;

[0056] The narrowband voice service selects the best channel for transmission among 75 VHF voice communication channels;

[0057] The broadband binary data communication service selects the best channel for transmission from channels to which no specific service functions are allocated;

[0058] The specific maritime safety information communication service selects the optimal channel for transmission among the AIS / ASM / VDE channels.

[0059] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention using the above disclosed contents without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the contents of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A multi-mode channel self-organizing elastic access method, characterized in that: The method comprises the following steps: S1. Determine idle channels through channel spectrum sensing; S2. Obtain the best available channel for data transmission of each service through channel quality assessment; S3. Select a corresponding channel to send signals according to different service transmission requirements.

2. A multi-mode channel self-organizing elastic access method according to claim 1, characterized in that: The specific steps of determining an idle channel by channel spectrum sensing in S1 are as follows: S1-1. The binary hypothesis test model is used as the channel spectrum sensing theoretical model. The received signal is filtered by bandpass filtering, filtering out high-frequency and low-frequency noise and interference signals, and only the valid signal y(t) in the frequency band to be detected is retained. The valid signal y(t) is sampled to obtain the discrete signal: y=(y1,y2,L y N ); S1-2, obtain the signal energy of each channel by obtaining the discretized signal, and determine whether there is a signal in the channel according to the set threshold ξ, If the signal exists, the channel cannot be used; If the signal does not exist, the channel is an idle channel and is used as a backup channel to send data.

3. A multi-mode channel self-organizing elastic access method according to claim 2, characterized in that: The binary hypothesis testing model described in S1-1 is: Where r(t) represents the received signal, n(t) represents the noise signal, s(t) represents the transmitted signal, H0 represents that there is no signal in the channel, and H1 represents that there is a signal in the channel.

4. A multi-mode channel self-organizing elastic access method according to claim 2, characterized in that: The definition of the decision statistic λ of whether the channel in S1-2 has signal spectrum sensing is as follows: When λ≥ξ, there is a signal in the channel and the channel cannot be used; When λ<ξ, the channel is an idle channel and is used as a backup channel to send data.

5. A multi-mode channel self-organizing elastic access method according to claim 1, characterized in that: The specific steps of step S2 are as follows: S2-1, the receiving station reports a signal-to-noise-plus-interference ratio in the relevant response message, and estimates the channel quality indicator based on the estimated value of the signal-to-noise-plus-interference ratio; S2-2. Select a channel with the largest channel quality index from the idle channels of each service as a candidate channel for subsequent data transmission.

6. A multi-mode channel self-organizing elastic access method according to claim 5, characterized in that: The channel quality indicator is an integer, occupies one byte, and ranges from 0 to 255.

7. A multi-mode channel self-organizing elastic access method according to claim 5, characterized in that: The relationship between the signal-to-noise ratio plus interference ratio SNIR and the channel quality indicator CQI in S2-1 is as follows: CQI=40+4SNIR When the signal-to-noise ratio plus interference ratio is less than -10.0dB, the minimum value of the channel quality index is 0; When the signal-to-noise ratio plus interference ratio is greater than 53.75dB, the maximum channel quality index is 255.

8. A multi-mode channel self-organizing elastic access method according to claim 5, characterized in that: The accuracy of the channel quality indicator is 0.25dB.

9. A multi-mode channel self-organizing elastic access method according to claim 1, characterized in that: The services in S3 include narrowband voice services, broadband binary data communication services, and specific maritime safety information communication services.

10. A multi-mode channel self-organizing elastic access method according to claim 9, characterized in that: The narrowband voice service selects the best transmission among 75 VHF voice communication channels; The broadband binary data communication service selects the best transmission from channels not assigned specific service functions; The specific maritime safety information communication service selects the optimal AIS / ASM / VDE channel for transmission.

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