CN116017364B

CN116017364B - Simulcast signal transmission method and device

Info

Publication number: CN116017364B
Application number: CN202310186865.0A
Authority: CN
Inventors: 欧阳建生; 狄隽; 康育贵
Original assignee: Guangdong Yuexin Microsystem Research Institute
Current assignee: Guangdong Yuexin Microsystem Research Institute
Priority date: 2023-03-02
Filing date: 2023-03-02
Publication date: 2023-06-27
Anticipated expiration: 2043-03-02
Also published as: CN116017364A

Abstract

The invention relates to a simulcast signal transmission method and device, belongs to the technical field of communication, and solves the problem that a session is discontinuous or even disconnected in a complex and changeable environment in the existing method. The method comprises the following steps: sequentially arranging command center communication vehicles and communication vehicles with fixed positions at the edge positions of an ad hoc network area, wherein the distances between adjacent communication vehicles are equal, and the command center communication vehicles, the communication vehicles with fixed positions and the motor patrol communication vehicles are respectively provided with a command center base station, a first base station, a second base station, a third base station, a fourth base station, a fifth base station and a seventh base station; distributing link time slots to the command center base station and the first to N base stations; the performing simulcast signal transmission by the user communication terminal and the respective base stations includes: receiving signals sent from a user communication terminal through a first adjacent base station and sending the signals to each base station; and forwarding the signal quality compared preferred signal through each base station. The uplink multipath uploading and the downlink preferential forwarding are adopted to avoid discontinuous or interruption of the session caused by high dynamic property of the application scene.

Description

Simulcast signal transmission method and device

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for transmitting simulcast signals.

Background

In earthquake relief and emergency sites, the wireless ad hoc network simulcast system with the survivability and independent of wired links is the optimal choice.

Common wireless ad hoc network simulcast systems are divided into two types, namely a centerless and a centerless, usually master-slave mode, and a centerless, usually fixed connection mode. The master-slave mode with the center is suitable for use scenes without wired link erection conditions and with just good erection positions of the master base station, such as a communication system in a forest area, and is not suitable for flexible and mobile earthquake relief and emergency on-site use. The centerless fixed connection mode is the most common in the private network communication industry at present, and can be applied to earthquake relief and emergency sites. Both transmitted signals are excellent signals which are judged at the beginning of the session establishment.

The prior art has the following disadvantages: the wireless ad hoc network simulcast system applied to earthquake relief and emergency sites at present transmits optimal signals judged at the beginning of session establishment, does not consider the dynamic nature of wireless signals in the session process, and can meet the use requirement under the site environment with good signal stability of a communication terminal through careful deployment and planning. However, when a complex and changeable field environment is encountered, the session effect is quite unsatisfactory, and the phenomenon of session discontinuity and even session disconnection can occur.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a simulcast signal transmission method and apparatus, so as to solve the problem that when the existing signal transmission party encounters a complex and changeable field environment, a session discontinuity or even a session disconnection occurs.

In one aspect, an embodiment of the present invention provides a simulcast signal transmission method, including: sequentially arranging command center ZH0 communication vehicles, fixed-position communication vehicles GD1, GD2, … and GDN-1 at the edge position of an ad hoc network area, wherein a command center base station is arranged on the command center ZH0 communication vehicles, and the fixed-position communication vehicles GD1, GD2, … and GDN-1 are respectively provided with a first base station, a second base station, …, an N-1 base station and a motor patrol communication vehicle XLN; distributing a link time slot to the command center base station, the first base station and the Nth base station; performing simulcast signal transmission through the user communication terminal and each base station, wherein performing simulcast signal transmission through the user communication terminal and each base station includes: receiving, by a first neighboring base station, a signal sent from the user communication terminal and sending a preferred signal from a downlink slot of the first neighboring base station, wherein the first neighboring base station is the command center base station, a plurality of base stations adjacent to the user communication terminal from among the first base station to the nth base station; and receiving the preferred signals through downlink time slots of wireless access channels from the command center base station, the first base station to the Nth base station, comparing signal quality of a plurality of preferred signals and forwarding the preferred signals according to comparison results.

The beneficial effects of the technical scheme are as follows: by adopting the uplink multipath uploading and downlink preferential forwarding methods, the user communication terminal is ensured to achieve the optimal receiving effect, and the session discontinuity or interruption caused by the high dynamic property of the application scene is avoided.

Based on a further improvement of the above method, allocating a link time slot to the command center base station, the first base station to the nth base station includes: sequentially allocating N downlink time slots to the command center base station, the first base station, the second base station and the N-1 base station according to …; and selecting 1 or 2 base stations with the best signal quality from the occupied N downlink time slots as the previous hop base station through the N base stations, and then randomly accessing the previous hop base station to apply for the uplink time slots.

Based on a further improvement of the above method, performing simulcast signal transmission by the user communication terminal and the respective base stations comprises: a session establishment phase, a session phase and a session ending phase, wherein a session request is initiated in the session establishment phase or session data is initiated in the session phase through the user communication terminal; receiving and storing the session request in the session request phase or receiving and storing the session data in the session request phase by the first neighboring base station; synchronizing a session request in the session establishment stage or receiving and storing the session request in a multipath manner in the session request stage through the command center base station, the first base station and the Nth base station; the first adjacent base station prefers to carry out a session request response in the session establishment stage, or the command center base station, the first base station and the N base station synchronously send out a session request response in the session establishment stage or prefers to send out session request data in the session request stage; actively initiating a session ending request at the session ending stage through the user communication terminal; and the Nth base station transmits a session maintenance overtime ending notification in the session ending stage.

Based on a further improvement of the above method, the nth base station session maintenance timeout end notification includes: when the Nth base station performs a session state, starting a session maintenance timeout timer, and judging that the session maintenance is overtime when a session data frame is not received before the session maintenance timeout timer is overtime; transmitting a session maintenance timeout end notification data frame in a downlink slot through the nth base station; and receiving and storing the session maintenance timeout end notification data frame with a second neighboring base station, wherein the second neighboring base station is neighboring the nth base station, wherein the first neighboring base station comprises the second neighboring base station and the nth base station; synchronously transmitting the session maintenance overtime ending notification data frame in a downlink time slot of a wireless link through the second adjacent base station; and determining whether to forward the session maintenance timeout end notification data frame in an uplink time slot or a downlink time slot of a wireless link according to a session information determination rule after receiving the session maintenance timeout end notification data frame by the command center base station, the first base station and the N-1 base station, wherein the session information determination rule comprises that the base station forwards when in the session stage and does not forward when in the session end stage.

Based on a further improvement of the above method, performing simulcast signal transmission by the user communication terminal and the respective base stations comprises: generating a session establishment request data frame through the user communication terminal, checking the session establishment request data frame, carrying out channel coding on the session establishment request data frame, and then sending the session establishment request data frame in an uplink time slot of a wireless access channel according to a random access rule; channel decoding is carried out on the received session establishment request data frame through the first adjacent base station, the session establishment request data frame is checked, and the session establishment request data frame is stored in a multipath mode; and transmitting the received session establishment request data frame in a corresponding wireless link time slot through the first adjacent base station, so that each of the command center base station, the first base station and the Nth base station receives the session establishment request data frame from at least one base station in the first adjacent base station.

Based on a further improvement of the above method, performing simulcast signal transmission by the user communication terminal and the respective base stations comprises: comparing the received session establishment request data frames through the command center base station, the first base station and the Nth base station, and selecting the Nth base station with the best signal quality to perform session request response data frames; and transmitting the received session request response data frame through the second adjacent base station through the corresponding wireless link time slot, so that each of the command center base station, the first base station and the N base station transmits the session request response data frame according to the signal quality optimization principle.

Based on a further improvement of the above method, performing simulcast signal transmission by the user communication terminal and the respective base stations comprises: generating a session data frame through the user communication terminal, checking the session data frame, encoding the session data frame which passes the checking, and then transmitting the session data frame in an uplink time slot of a wireless access channel; channel decoding and checking are carried out on the received session data frames through the first adjacent base station, and then the session data frames which pass the checking are stored in a multipath mode; transmitting the session data frame through each base station in the first adjacent base stations through a wireless link time slot, and receiving the session establishment request from at least one base station in the first adjacent base stations and storing the session establishment request in multiple ways by the command center base station and each base station from the first base station to the Nth base station; and comparing the signal quality of the stored multipath session data through the command center base station, the first base station and the N-th base station, and broadcasting the session data with the optimal signal quality in the corresponding link time slot.

In another aspect, an embodiment of the present invention provides a simulcast signal transmission apparatus, including: the base station is used for sequentially arranging a command center ZH0 communication vehicle, fixed-position communication vehicles GD1, GD2, … and GDN-1 at the edge position of an ad hoc network area and the distances between adjacent communication vehicles are equal, wherein the command center ZH0 communication vehicle is provided with a command center base station, the fixed-position communication vehicles GD1, GD2, … and GDN-1 are respectively provided with a first base station, a second base station, …, an N-1 base station and an N base station; the time slot allocation module is used for allocating a link time slot to the command center base station, the first base station and the N base station; the system comprises a simulcast signal transmission module, a transmission module and a transmission module, wherein the simulcast signal transmission module is used for executing simulcast signal transmission through a user communication terminal and each base station, and comprises an uplink multipath uploading module and a downlink preferential forwarding module, wherein the uplink multipath uploading module is used for receiving signals sent by the user communication terminal through a first adjacent base station and sending preferential signals from downlink time slots of the first adjacent base station, and the first adjacent base station is the command center base station, and a plurality of base stations adjacent to the user communication terminal in the first base station to the Nth base station; and the downlink preferential forwarding module is used for receiving the preferential signals through downlink time slots of wireless access channels from the command center base station, the first base station to the Nth base station, comparing signal quality of a plurality of preferential signals and forwarding the preferential signals according to comparison results.

Based on a further improvement of the above device, the time slot allocation module is configured to allocate N downlink time slots to the command center base station, the first base station, the second base station, …, and the N-1 base station in sequence; and the N base station selects 1 or 2 base stations with the best signal quality from the occupied N downlink time slots as the previous hop base station, and then applies for the uplink time slots to the previous hop base station through random access.

Based on a further improvement of the above apparatus, each of the command center base station, the first base station, and the nth base station includes: the base station controller signal processing module, the wireless access channel receiving module, the wireless link channel transmitting module, the wireless link channel receiving module and the wireless access channel generating module, wherein the wireless access channel receiving module is used for decoding and receiving signal data frames sent by a user communication terminal through a physical layer channel, checking the signal data frames through a data link layer, synchronously numbering the checked signal data frames, filling the signal data frame numbers SDN, and transmitting the signal data frames to the base station controller signal processing module; the base station controller signal processing module is configured to perform uplink data processing and downlink data processing, where the uplink data processing is configured to, after receiving a signal data frame from the radio access channel receiving module and filling a source base station number BSN and a radio access forwarding time slot number FSN into the received signal data frame, determine which signal data frame is sent in a downlink time slot according to signal quality of multiple paths of signal data; the downlink data processing is used for optimizing according to the signal quality after receiving the signal data of the uplink time slot of the wireless access channel and the signal data of each time slot of the wireless link channel, and transmitting the optimized signal to the wireless access channel transmitting module before the wireless access forwarding time slot number TSN; the wireless link channel transmitting module is used for receiving the signal data sent by the base station controller signal processing module, transmitting the signal data to a data link layer, and transmitting the signal data to other previous-hop base stations and next-hop base stations after channel coding of a physical layer; the wireless link channel receiving module is used for decoding and receiving signal data of each time slot of the wireless link through a physical layer channel, checking through a data link layer and immediately transmitting the signal data to the base station controller signal processing module after the checking; the wireless access channel transmitting module is used for extracting the wireless access forwarding time slot number TSN in the signal data frame after receiving the signal data of the base station controller signal processing module, and transmitting the effective signal data to the user communication terminal after carrying out channel coding on the effective signal data by synchronous control.

Compared with the prior art, the invention has at least one of the following beneficial effects:

1. by adopting the uplink multipath uploading and downlink preferential forwarding methods, the user communication terminal is ensured to achieve the optimal receiving effect, and the session discontinuity or interruption caused by the high dynamic property of the application scene is avoided.

2. The invention can solve the problems of discontinuous conversation and even interruption of conversation caused by the non-ideal conversation effect of the high dynamic environment through the optimized forwarding rule of the link channel and the access channel.

3. The optimized simulcast signal transmission method can be used for self-adaptive wireless link simulcast systems in the scenes of earthquake relief, emergency, safety guarantee and the like.

In the invention, the technical schemes can be mutually combined to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, like reference numerals being used to designate like parts throughout the drawings;

Fig. 1 is a flowchart of a simulcast signal transmission method according to an embodiment of the present invention;

fig. 2 is a schematic diagram of multiple upload/best forwarding according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a simulcast signal transmission procedure according to an embodiment of the present invention;

fig. 4 is a diagram of a signal transmission flow of an access channel according to an embodiment of the present invention;

fig. 5 is a schematic diagram of signal transmission of a link channel according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a system composition of a security ad hoc network emergency communication system around a large-scale stadium according to an embodiment of the present invention;

FIG. 7 is a diagram illustrating uplink and downlink timeslot allocations for an individual base station during XL4 patrol according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a simulcast signal transmission process of XL4 during eastern patrol according to an embodiment of the present invention;

fig. 9 is a block diagram of a simulcast signal transmission apparatus according to an embodiment of the present invention.

Detailed Description

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and together with the description serve to explain the principles of the invention, and are not intended to limit the scope of the invention.

Referring to fig. 1, a method for transmitting simulcast signals is disclosed in an embodiment of the present invention, including: in step S102, sequentially setting command center ZH0 communication vehicles, fixed-position communication vehicles GD1, GD2, … and GDN-1 at the edge position of the ad hoc network area and the distances between adjacent communication vehicles are equal, wherein a command center base station is arranged on the command center ZH0 communication vehicle; the fixed-position communication vehicles GD1, GD2, … and GDN-1 are respectively provided with a first base station, a second base station, …, an N-1 base station and an N base station, and the motor patrol communication vehicle XLN is provided with the motor patrol communication vehicle; in step S104, link time slots are allocated to the command center base station, the first base station, and the nth base station; in step S106, the simulcast signal transmission is performed by the user communication terminal and each base station, wherein the performing the simulcast signal transmission by the user communication terminal and each base station includes: receiving a signal sent from a user communication terminal through a first adjacent base station and sending a preferred signal from a downlink time slot of the first adjacent base station, wherein the first adjacent base station is a command center base station, a plurality of base stations adjacent to the user communication terminal from a first base station to an N base station; and receiving the preferred signals through the command center base station, the downlink time slots of the wireless access channels from the first base station to the Nth base station, comparing the signal quality of the preferred signals and forwarding the preferred signals according to the comparison result. For example, when the command center base station transmits a preferred signal as a first neighboring base station, the first base station, the N-1 th base station, and the N-th base station neighboring the command center base station receive the preferred signal; or when the first base station sends out a preferred signal as the first adjacent base station, the command center base station, the second base station and the nth base station receive the preferred signal, etc.

Compared with the prior art, the simulcast signal transmission method provided by the embodiment adopts the uplink multipath uploading (namely, the first adjacent base station receives the signal sent from the user communication terminal) and the downlink preferential forwarding method, so that the user communication terminal is ensured to achieve the optimal receiving effect, and the session discontinuity or interruption caused by the high dynamic property of the application scene is avoided.

Hereinafter, each step of the simulcast signal transmission method according to an embodiment of the present invention will be described in detail with reference to fig. 1.

In step S102, sequentially setting command center ZH0 communication vehicles, fixed-position communication vehicles GD1, GD2, … and GDN-1 at the edge position of the ad hoc network area and the distances between adjacent communication vehicles are equal, wherein a command center base station is arranged on the command center ZH0 communication vehicle; the fixed-position communication vehicles GD1, GD2, …, GDN-1 are provided with a first base station, a second base station, …, an N-1 base station, and the motor patrol communication vehicle XLN is provided with an N-th base station, respectively. For example, the ad hoc network area comprises a disaster relief scene, an emergency scene, a safety guarantee scene and the like. N is an integer greater than 2, preferably N is 4 to 10, etc. Referring to fig. 6, when N is 4, GD1, GD2, and GD3 are fixed-position communication vehicles, and XL4 is a motor patrol vehicle. The mobile patrol car XL4 can move in the ad hoc network area.

In step S104, a link slot is allocated to the command center base station, the first base station, and the nth base station. The step of allocating the link time slot to the command center base station, the first base station and the N base station comprises the following steps: sequentially distributing N downlink time slots to a command center base station, a first base station, a second base station and a … N-1 base station; and selecting 1 or 2 base stations with the best signal quality from the occupied N downlink time slots as the previous hop base station through the N base station, and then randomly accessing the previous hop base station to apply for the uplink time slot. For example, 4 downlink time slots are sequentially allocated to a command center base station, a first base station, a second base station, and a third base station; and selecting 1 or 2 base stations with the best signal quality from the 4 occupied downlink time slots as the last-hop base station through the fourth base station, and then applying for the uplink time slots to the last-hop base station through random access.

In step S106, the simulcast signal transmission is performed by the user communication terminal and each base station, wherein the performing the simulcast signal transmission by the user communication terminal and each base station includes: receiving a signal sent from a user communication terminal through a first adjacent base station and sending a preferred signal from a downlink time slot of the first adjacent base station, wherein the first adjacent base station is a command center base station, a plurality of base stations adjacent to the user communication terminal from a first base station to an N base station; and receiving the preferred signals through downlink time slots of wireless access channels of the command center base station, the first base station and the Nth base station, comparing signal quality of a plurality of preferred signals and forwarding the preferred signals according to the comparison result. Referring to fig. 7, the user communication terminal may be a first user communication terminal U1, a second user communication terminal U2, a third user communication terminal U3, or a fourth user communication terminal U4. Specifically, when the motor patrol communication car XLN is located on the eastern side, the first neighboring base station may be a base station neighboring the first user communication terminal U1, including a command center base station, a first base station, and a fourth base station; when the motor patrol car XLN is located in the south, the base stations adjacent to the second user communication terminal U2 include a first base station, a second base station, and a fourth base station; when the motor patrol car XLN is located on the west, the base stations adjacent to the third user communication terminal U3 include a second base station, a third base station, and a fourth base station; when the motor patrol car XLN is located on the north, the base stations adjacent to the fourth user communication terminal U4 include a command center base station, a third base station, and a fourth base station.

The performing simulcast signal transmission by the user communication terminal and the respective base stations includes: session establishment phase, session phase and session end phase. Specifically, a session request is initiated in a session establishment stage or session data is initiated in a session stage through a user communication terminal; receiving and storing a session request in a session request phase or receiving and storing session data in a session request phase by a first neighbor base station; synchronizing a session request in a session establishment stage or receiving and storing the session request in a multipath manner in a session request stage through a command center base station, a first base station and an Nth base station; the first adjacent base station prefers to perform session request response in the session establishment phase, or the command center base station, the first base station and the Nth base station synchronously issue session request response in the session establishment phase or prefers session request data and issues the session request data in the session request phase; actively initiating a session ending request at a session ending stage through the user communication terminal; and the Nth base station transmits a session maintenance overtime ending notification in a session ending stage.

The performing simulcast signal transmission by the user communication terminal and the respective base stations includes: generating a session establishment request data frame through a user communication terminal, checking the session establishment request data frame, carrying out channel coding on the session establishment request data frame, and then sending the session establishment request data frame in an uplink time slot of a wireless access channel according to a random access rule; channel decoding is carried out on the received session establishment request data frame through the first adjacent base station, the session establishment request data frame is checked, and the session establishment request data frame is stored in multiple ways; and transmitting the received session establishment request data frame in the corresponding wireless link time slot through the first adjacent base station, so that each of the command center base station, the first base station and the N base station receives the session establishment request data frame from at least one base station in the first adjacent base station.

The performing simulcast signal transmission by the user communication terminal and the respective base stations includes: comparing the received session establishment request data frames through the command center base station, the first base station and the Nth base station, and selecting the Nth base station with the best signal quality to carry out a session request response data frame; and transmitting the received session request response data frame through the corresponding wireless link time slot by the second adjacent base station, so that each of the command center base station, the first base station and the N base station transmits the session request response data frame according to the signal quality optimization principle.

The performing simulcast signal transmission by the user communication terminal and the respective base stations includes: generating a session data frame through a user communication terminal, checking the session data frame, encoding the session data frame which passes the checking, and then transmitting the session data frame in an uplink time slot of a wireless access channel; channel decoding and checking are carried out on the received session data frames through the first adjacent base station, and then the session data frames which pass the checking are stored in a multipath mode; transmitting a session data frame through each of the first neighboring base stations through a wireless link time slot, and each of the command center base station, the first base station, and the nth base station receives a session establishment request from at least one of the first neighboring base stations and stores the session establishment request in multiple ways; and comparing the signal quality of the stored multipath session data through the command center base station, the first base station and the N base station, and broadcasting the session data with optimal signal quality in the corresponding link time slot.

The nth base station session maintenance timeout end notification includes: when the Nth base station performs a session state, starting a session maintenance timeout timer, and judging that the session maintenance is overtime when a session data frame is not received before the session maintenance timeout timer is overtime; transmitting a session maintenance timeout end notification data frame in a downlink slot through an nth base station; and receiving and storing a session maintenance timeout end notification data frame with a second neighboring base station, wherein the second neighboring base station is neighboring an nth base station, wherein the second neighboring base station comprises a first neighboring base station and an nth base station; transmitting a session maintenance overtime end notification data frame in a downlink time slot synchronous manner through a second adjacent base station; and judging whether the session maintenance overtime end notification data frame needs to be forwarded in an uplink time slot or a downlink time slot of the wireless link according to a session information judging rule after receiving the session maintenance overtime end notification data frame through the command center base station, the first base station and the N-1 base station, wherein the session information judging rule comprises that the base station forwards when in a session stage and does not forward when in the session end stage. Referring to fig. 7, in particular, when the motor patrol communication car XLN is located on the east, the second adjacent base station may be a base station adjacent to the fourth base station, including the command center base station and the first base station; when the motor patrol car XLN is located in the south, the base stations adjacent to the fourth base station include a first base station and a second base station; when the motor patrol car XLN is located on the west, the base stations adjacent to the fourth base station, including the second base station and the third base station; when the motor patrol car XLN is located on the north, the base stations adjacent to the fourth base station include a command center base station and a third base station.

Referring to fig. 9, in one embodiment of the present invention, a simulcast signal transmission apparatus is disclosed, including: the base station 902 is configured to sequentially set the command center ZH0 communication vehicle, the fixed-position communication vehicles GD1, GD2, and GDN-1 at edge positions of the ad hoc network area, where distances between adjacent communication vehicles are equal, and the command center ZH0 communication vehicle is provided with a command center base station; the fixed-position communication vehicles GD1, GD2, … and GDN-1 are respectively provided with a first base station, a second base station, … and an N-1 base station, and the motor patrol communication vehicle XLN is provided with an N base station; a time slot allocation module 904, configured to allocate a link time slot to the command center base station, the first base station, and the nth base station; the simulcast signal transmission module 906 is configured to perform simulcast signal transmission through the user communication terminal and each base station, where the simulcast signal transmission module includes an uplink multipath uploading module and a downlink preferential forwarding module, and the uplink multipath uploading module 908 is configured to receive, through a first neighboring base station, a signal sent from the user communication terminal and send a preferential signal from a downlink timeslot of the first neighboring base station, where the first neighboring base station is a command center base station, and a plurality of base stations adjacent to the user communication terminal from among the first base station to the nth base station; and a downlink preferred forwarding module 910, configured to receive the preferred signals through downlink timeslots of radio access channels of the command center base station, the first base station, and the nth base station, compare signal qualities of the plurality of preferred signals, and forward the forwarded preferred signals according to the comparison result.

The timeslot allocation module 904 is further configured to allocate N downlink timeslots to the command center base station, the first base station, the second base station, …, and the N-1 th base station in order; and the N base station is used for selecting 1 or 2 base stations with the best signal quality from the occupied N downlink time slots as the previous hop base station, and then applying for the uplink time slots to the previous hop base station by random access.

Each of the command center base station, the first base station, and the nth base station includes: the base station controller comprises a base station controller signal processing module, a wireless access channel receiving module, a wireless link channel transmitting module, a wireless link channel receiving module and a wireless access channel generating module.

The wireless access channel receiving module is used for decoding and receiving signal data frames sent by the user communication terminal through a physical layer channel, checking the signal data frames through a data link layer, synchronously numbering the checked signal data frames, filling the signal data frame numbers SDN, and then transmitting the signal data frames to the base station controller signal processing module. The base station controller signal processing module is used for executing uplink data processing and downlink data processing, wherein the uplink data processing is used for determining which signal data frame is transmitted in a downlink time slot according to the signal quality of the multipath signal data after receiving the signal data frame from the wireless access channel receiving module and filling a source base station number BSN and a wireless access forwarding time slot number FSN into the received signal data frame; and the downlink data processing is used for optimizing according to the signal quality after receiving the signal data of the uplink time slot of the wireless access channel and the signal data of each time slot of the wireless link channel, and transmitting the optimized signal to the wireless access channel transmitting module before the wireless access forwarding time slot number TSN. The wireless link channel transmitting module is used for receiving the signal data sent by the base station controller signal processing module, transmitting the signal data to the data link layer, and transmitting the signal data to other previous-hop base stations and next-hop base stations after channel coding of the physical layer. The wireless link channel receiving module is used for decoding and receiving the signal data of each time slot of the wireless link through the physical layer channel, checking through the data link layer, and immediately transmitting the checked signal data to the base station controller signal processing module. And the wireless access channel transmitting module is used for extracting the wireless access forwarding time slot number TSN in the signal data frame after receiving the signal data of the signal processing module of the base station controller, and transmitting the effective signal data to the user communication terminal after carrying out channel coding on the effective signal data by synchronous control.

Hereinafter, a simulcast signal transmission method according to an embodiment of the present invention will be described in detail by way of specific examples with reference to fig. 2 to 8.

The simulcast signal transmission method comprises the following contents:

content 1: general transmission principle of simulcast signals

The problem of non-ideal conversation effect under the high dynamic environment is solved, the signal transmission method of uplink multipath uploading and downlink preferential forwarding is adopted, as shown in fig. 2, the uplink signal S of the user communication terminal is simultaneously received by the base station 1 and the base station 2, and through the optimized transmission of the signals, the downlink signal forwarded by each base station on a wireless access channel is optimal finally, such as D1 and D2.

The transmission principle of uplink multipath uploading and downlink preferential forwarding is decomposed as follows:

1. the simulcast base station of the selected downlink time slot directly transmits the signal data received from the user communication terminal on the selected downlink time slot.

2. And the simulcast base station with the previous-hop simulcast base station transmits the signal data received from the user communication terminal on the uplink time slot of the random access application.

3. The co-broadcast base station without the non-selected downlink time slot and the last-hop co-broadcast base station is an independent base station, and can directly forward the signal data received from the user communication terminal without transmitting to a wireless link.

4. And all simulcast base stations monitor and receive the signal data of all uplink/downlink time slots at the same time, select optimal signal data for buffering according to the signal quality in the signal data, and then forward the signal data through the wireless access subsystem according to the corresponding forwarding time slots.

Content 2: co-broadcast signal transmission process

The simulcast signal transmission method of the embodiment of the invention is suitable for a self-adaptive wireless link simulcast system, is realized in a base station, and can improve the communication effect of the universal user communication terminal in a high dynamic environment under the condition of not changing the universal user communication terminal.

The transmission of simulcast signals is required to pass through the following modules inside the base station: the base station controller comprises a base station controller signal processing module, a wireless access channel receiving module, a wireless link channel transmitting module, a wireless link channel receiving module and a wireless access channel transmitting module.

The simulcast signal transmission process is divided into a total of 6 sub-processes as shown in fig. 3, and a processing method of each sub-process is described in detail below.

1. Wireless access channel receiving process

The wireless access channel receiving module firstly decodes and receives signals sent by the user communication terminal through a physical layer channel, then checks signal data through a data link layer, synchronously numbers checked signal data frames, fills signal data frame numbers SDN (Signal Data Number), and then transmits the signal data frames to the base station controller.

2. Uplink data processing of signal processing module of base station controller

The base station controller signal processing module receives the signal data frame of the wireless access channel receiving module, fills the source base station number BSN (Basestation Number) and the wireless access forwarding time slot number FSN (Forward Slot Number), performs optimization according to the signal quality of the multipath signal data, and then decides which path of signal data is transmitted in the downlink time slot. The signal data has multiple paths including each other time slot except the downlink time slot of the wireless link and the uplink time slot of the wireless access channel. The usual procedure is as follows: at the beginning of the session, the downlink time slot transmits uplink time slot signal data of the wireless access channel; during the session, the downlink time slot transmits signal data that is preferred according to signal quality.

3. Wireless link channel transmitting module

The wireless link channel transmitting module receives the signal data sent by the base station controller signal processing module, transmits the signal data to the data link layer, and then sends the signal data to other previous-hop base stations and next-hop base stations after channel coding of the physical layer.

4. Wireless link channel receiving module

The wireless link channel receiving module firstly decodes and receives the signal data of each time slot of the wireless link through the physical layer channel, then checks the signal data through the data link layer, and immediately transmits the signal data to the base station controller signal processing module after the check is successful.

5. Downlink data processing by signal processing module of base station controller

The base station controller signal processing module receives the signal data of the uplink time slot of the wireless access channel and the signal data of each time slot of the wireless link channel, performs optimization according to the signal quality, and timely transmits the optimized signal to the wireless access channel transmitting module before the wireless access forwarding time slot number TSN.

6. Wireless access channel transmitting module

After receiving the signal data of the signal processing module of the base station controller, the wireless access channel transmitting module extracts the wireless access forwarding time slot number TSN in the signal data frame, and the effective signal data is transmitted to the user terminal after being subjected to channel coding by synchronous control.

Content 3: uplink/downlink signal transmission method of access channel

The user communication terminal initiates a session request in a random access mode in an uplink time slot of a wireless access channel, and transmits signal data on a designated uplink time slot in the session process; the wireless access channel of the base station analyzes the signal to noise ratio of the signal, detects the field intensity of the signal and numbers the signal data frames while receiving the signal of the user communication terminal.

All base stations, whether from the downlink time slot of the radio link channel or the uplink time slot of the radio access channel, need to forward synchronously on time on the downlink time slot of the radio access channel according to the radio access forwarding time slot number in the signal data.

The signal transmission flow of the access channel is shown in fig. 4, and is described in detail as follows:

A. the user communication terminal sends a session establishment request data frame according to random access rules on an uplink time slot of the wireless access channel according to user requirements, wherein the session establishment request data frame comprises, but is not limited to, a destination user terminal address, a service type and the like. The transmission process includes, but is not limited to, the application layer forming a session establishment request data frame, the data link layer checking the session establishment request data frame, the physical layer performing channel coding and synchronous transmission control on the session establishment request data frame, and the like.

B. The base station receives the session establishment request data frame of the user communication terminal through physical layer channel decoding of the wireless access transceiver, data link layer data verification and transmits to the base station controller, and records session information, wherein the session information comprises, but is not limited to, the wireless access transceiver, an originating user terminal address, a destination user terminal address and the like. The base station controller forms a session request response data frame according to the request service type, transmits the session request response data frame back to the wireless access transceiver through a data link route, and transmits the session request response data frame to the user communication terminal after channel coding and synchronous transmitting control are carried out on the session request response data frame through a data link layer of the wireless access transceiver and a physical layer, and the user terminal indicates that the session is established successfully after receiving the session request response data frame and starts to transmit the session data frame. The base station controller synchronously transmits the session request response data frame to the wireless link transceiver, and after the channel coding is carried out on the session request response data frame through the wireless link transceiver link layer checking session request response data frame and the physical layer, the base station controller transmits the session request response data frame to other previous-hop base stations or next-hop base stations in the downlink time slot or the uplink time slot of the base station.

After Cn. session establishment, the base station receives and stores uplink multipath signals according to the session information. The multipath signal includes an uplink session data frame of the radio access transceiver, a local uplink time slot session data frame of the radio link transceiver, and other downlink time slot session data frames. The uplink session data frame receiving process of the wireless access transceiver comprises the steps that a physical layer of the wireless access transceiver carries out channel decoding on the session data frame, a data link layer checks the session data frame, and a base station controller application layer stores the session data frame in a multipath mode. The receiving and processing processes of the local uplink time slot session data frame and other downlink time slot signal data of the wireless link transceiver are the same, the physical layer of the wireless link transceiver is included to carry out channel decoding on the session data frame, the data link layer checks the session data frame, and the base station controller application layer stores the session data frame in a multipath mode.

After Dn. session establishment, the base station performs the preference and transmission of the downlink session data frame according to the session information. The downlink session data frame is preferably selected according to the signal quality of the multi-channel session data frame after receiving and storing the multi-channel session data frame by Cn, so as to ensure the signal quality of the downlink session data frame and the communication effect of the user communication terminal. The sending process of the downlink session data frame comprises the application layer downlink signal optimization and the data link layer routing of the base station controller, the data link layer checking session data frame of the wireless access transceiver, and the physical layer performing channel coding and synchronous transmission control on the session data frame.

En. the initiator actively ends the session, and the user communication terminal actively initiates a session end request data frame in the service uplink time slot according to the need. The session end request data frame includes, but is not limited to, destination user terminal address, service type, etc. The transmission process includes, but is not limited to, the application layer forming a session end request data frame, the data link layer checking the data frame, the physical layer performing channel coding and synchronous transmission control on the session end request data frame, and so on.

The Fn. base station receives the session end request data frame of the user communication terminal through physical layer channel decoding of the wireless access transceiver, data link layer data check and transmits to the base station controller, and records session information including, but not limited to, wireless access transceiver, originating user terminal address, destination user terminal address, etc. The base station controller forms a session ending request data frame according to the request service type, transmits the session ending request data frame back to the wireless access transceiver through a data link route, checks the session ending request data frame through a data link layer of the wireless access transceiver, performs channel coding and synchronous transmission control on the session ending request data frame through a physical layer, and then transmits the session ending request data frame to the user communication terminal, and after receiving the session ending request data frame, the user terminal indicates that the session is ended successfully and stops transmitting the session data frame. The base station controller synchronously transmits the session ending response data frame to the wireless link transceiver, and after the channel coding is carried out on the session ending response data frame through the link layer check session ending response data frame of the wireless link transceiver and the physical layer, the base station controller transmits the session ending response data frame to other previous hop base stations or next hop base stations in the downlink time slot or the uplink time slot of the base station.

Gn. session maintenance timeout end notification is initiated by the base station, which can quickly release session resources in case of failure of the user communication terminal session end request. The base station controller forms a session maintenance overtime end notification data frame according to the request service type, transmits the session maintenance overtime end notification data frame back to the wireless access transceiver through a data link route, checks the session maintenance overtime end notification data frame through a data link layer of the wireless access transceiver, and transmits the session maintenance overtime end notification data frame to the user communication terminal after channel coding and synchronous transmission control are carried out on the session maintenance overtime end notification data frame by a physical layer, and the user terminal indicates that the session is ended successfully after receiving the session maintenance overtime end notification data frame and stops transmitting the session data frame. The base station controller synchronously transmits the session maintenance overtime end notification data frame to the wireless link transceiver, and after the session maintenance overtime end notification data frame is checked by the link layer of the wireless link transceiver and the physical layer carries out channel coding on the session maintenance overtime end notification data frame, the session maintenance overtime end notification data frame is transmitted to other previous-hop base stations or next-hop base stations in the downlink time slot or the uplink time slot of the base station.

Content 4: uplink/downlink signal transmission method of link channel

The method is limited to the base station without the selected downlink time slot, and when the signal transmission requirement exists, the transmission is required to be carried out through the applied uplink time slot. A base station that does not select a downlink slot cannot transmit on the radio link without applying for uplink slot resources.

The base station is limited to the selected downlink time slot, and needs to transmit through the selected downlink time slot when there is a signal transmission requirement. If uplink time slot resources are simultaneously applied, signals need to be synchronously transmitted on uplink time slots.

The signal transmission schematic diagram of the link channel is shown in fig. 5, and the link channel signal transmission of any base station is divided into two parts of multipath receiving and preferential forwarding:

multipath reception includes reception of a radio access channel uplink time slot signal, reception of an uplink signal of the own base station, and reception of all downlink time slot signals. The wireless access channel uplink time slot signal receiving process comprises, but is not limited to, physical layer channel decoding of a wireless access transceiver, data link layer data verification, data link layer forwarding, base station controller multipath storage and the like; the uplink time slot signal receiving and all downlink time slot signal receiving of the base station have the same processing procedures, including but not limited to physical layer channel decoding of a wireless link transceiver, data link layer data verification, data link layer forwarding, multi-channel storage of a base station controller and the like.

The preferred forwarding includes an optimal transmission of the own base station downlink time slot signal and an optimal transmission of the uplink time slot signal of the previous hop base station. The optimal sending of the uplink time slot signal of the base station and the optimal forwarding of the uplink time slot signal of the last hop base station have the same processing procedures, including but not limited to the base station controller application layer multipath preferred signal data frame, the wireless link transceiver data link layer checking the preferred signal data frame, the physical layer performing channel coding and synchronous transmitting control on the preferred signal data frame, and the like.

Content 1: system composition

The security ad hoc network emergency communication system around the large-scale stadium is generally composed of 5 ad hoc network base stations and a plurality of user communication terminals, wherein 1 of the system is placed in a command and dispatch center, and the other 4 system are placed on emergency communication vehicles. As shown in fig. 6, the command and dispatch center is a ZH0 communication car, GD1, GD2 and GD3 are fixed-position communication cars, XL4 is a motor patrol communication car, and U1, U2, U3 and U4 are user communication terminals.

Content 2: link time slot allocation

The downlink time slot allocation for each base station and the uplink time slot allocation during XL4 patrol are shown in fig. 7. According to the invention, an 8-time slot wireless link is adopted, when ZH0, GD1, GD2 and GD3 occupy all 4 downlink time slots of 1,3,5 and 7, the XL4 cannot reassign the downlink time slots, only 1 or 2 base stations with better signal quality can be optimized from the occupied downlink time slots to serve as the last-hop base station, and then the last-hop base station is randomly accessed to apply for uplink time slot resources. When XL4 patrol around stadium, according to the signal quality of downlink time slot signal, DS1 and DS3 signal quality is better at east, US2 and US4 are uplink time slots; in the south, the signal quality of DS3 and DS5 is better, and US4 and US6 are uplink timeslots; in the western aspect, the signal quality of DS5 and DS7 is better, and US6 and US8 are uplink time slots; in the north, the signal quality of DS1 and DS7 is better, and US2 and US8 are uplink timeslots.

Content 2: co-cast signal transmission

The transmission process of the simulcast signal is described by taking the communication of XL4 when patrol is performed on the eastern side as shown in fig. 7.

ZH0, GD1 and XL4 may all receive the signal sent by U1, while ZH0, GD1 and XL4 may also receive the preferred signal sent by each base station downlink timeslot, GD2 may receive the preferred signal sent by GD1 downlink timeslot, and GD3 may receive the preferred signal sent by ZH0 downlink timeslot. This process is uplink multiple uploads.

The signals forwarded by the ZH0, GD1 and XL4 downlink time slots are optimized after signal quality comparison, and the compared signals comprise uplink time slot signals of a wireless access channel and uplink/downlink time slot signals of a wireless link channel; the signals sent by the downlink timeslots of the radio access channels ZH0, GD1, GD2, GD3 and XL4 are also preferred after signal quality comparison, the compared signals comprising the uplink timeslot signals of the radio access channels and the uplink/downlink timeslots signals of the radio link channels. This procedure is downstream preferred forwarding.

The detailed simulcast signal transmission flow is as follows:

1. session establishment

The session establishment procedure is subdivided in total into the following 5 steps:

1. user communication terminal U1 initiates a session request

U1 forms a session establishment request data frame through a control module application layer, a link layer checks the session establishment request data frame, a physical layer carries out channel coding on the session establishment request data frame, and then the session establishment request data frame is sent out in a time slot on a wireless access channel according to a random access rule, and ZHO, GD1 and XL4 can be received.

2. ZHO, GD1 and XL4 receive session requests

The ZHO, GD1, and XL4 channel-decodes the session establishment request data frame through the physical layer of the radio access transceiver, verifies the session establishment request data frame at the data link layer, multiplexes the session establishment request data frame at the base station controller, and creates session information.

3. ZH0, GD1, GD2, GD3, and XL4 synchronous session requests

ZH0 transmits the session establishment request data frame received in step 2 through the downlink timeslot DS1 of the wireless link, and GD1, GD3 and XL4 may all be received.

GD1 sends the session establishment request data frame received in step 2 through the wireless link downlink timeslot DS3, and ZH0, GD2 and XL4 may all be received.

XL4 sends the session establishment request data frame received in step 2 through the downlink time slot US2/US4 of the wireless link, and both ZH0 and GD1 can be received.

4. ZHO, GD1 and XL4 preferably do session request replies

After ZHO, GD1 and XL4 are subjected to the step 3 synchronous session request, XL4 with the best received signal quality is selected for session request response.

5. ZH0, GD1, GD2, GD3 and XL4 synchronously issued session request replies

The synchronization control logic of the session request reply is the same as step 3, but the transmitted data frame is replaced by the session establishment request data frame.

After the session request response is synchronized, ZH0, GD1, GD2, GD3 and XL4 issue the session request response, and the issue needs to follow the principle of signal quality optimization.

2. In a conversation

After the session is established, the base stations ZH0, GD1, GD2, GD3 and XL4 and the user communication terminals U1, U2, U3 and U4 all enter a session state, and the signal transmission process in the session will be described in detail below by taking the U1 transmission session data frame as an example.

1. User communication terminal U1 initiates session data

U1 forms a session data frame through a control module application layer, a link layer checks the session data frame, a physical layer carries out channel coding on the session data frame, and then the session data frame is instantly sent out in a time slot on a wireless access channel, and ZHO, GD1 and XL4 can all be received.

2. ZHO, GD1 and XL4 receive and store session data

ZHO, GD1 and XL4 channel decode the session data frames through the physical layer of the wireless access transceiver, data link layer check the session data frames, and the base station controller multiplexes the session data frames.

3. ZH0, GD1, GD2, GD3 and XL4 for multiplexing and storing session data

ZH0 transmits the session data frame received in step 2 through the downlink timeslot DS1 of the wireless link, and GD1, GD3 and XL4 may all be received and stored.

GD1 transmits the session data frame received in step 2 via the wireless link downlink timeslot DS3, and ZH0, GD2 and XL4 may all be received and stored.

XL4 transmits the session data frame received in step 2 via the downlink radio link time slot US2/US4, and both ZH0 and GD1 may be received and stored.

4. ZH0, GD1, GD2, GD3 and XL4 preferred session data are issued

After ZH0, GD1, GD2, GD3 and XL4 receive and store session data in the 3 rd step, before sending a session data frame in the downlink time slot of the wireless access channel, the session data with the best received signal quality is selected and sent out in the downlink time slot of the wireless access channel according to the stored multi-channel session data for optimization.

3. Session end

Session termination is divided into two cases: firstly, a user communication terminal U1 actively initiates a session ending request; and secondly, the base station XL4 session maintenance timeout end notification. The flow and steps of the user communication terminal U1 for actively initiating the session ending request are identical to those of the user communication terminal U1 for initiating the session establishment request. The flow steps of the base station XL4 session maintenance timeout completion notification are described in detail herein.

1. XL4 session maintenance timeout determination

When XL4 enters the in-session state, a session maintenance timeout timer is started, and is restarted each time a session data frame is received. If XL4 has not received a session data frame before the session maintenance timeout timer times out, then the session maintenance timeout is determined.

2. XL4 sends session maintenance timeout end notification

XL4 composes a session maintenance timeout end notification data frame through the base station controller application layer, and the link layer routes the synchronous forwarding to the radio link transceiver and the radio access transceiver. The wireless access transceiver checks the overtime end notification data frame of the session maintenance through the data link layer, the physical layer carries out channel coding on the overtime end notification data frame of the session maintenance, and the wireless access transceiver sends out the frame in the downlink time slot of the session, and the base station enters the session end state. The wireless link transceiver checks the session maintenance timeout end notification data frame through the data link layer, the physical layer performs channel coding on the session maintenance timeout end notification data frame, and the session maintenance timeout end notification data frame is sent out on the downlink time slot US2/US4, and can be received by both ZHO and GD 1.

3. ZH0 and GD1 receive session maintenance timeout end notification

ZHO and GD1 channel decode the session maintenance timeout completion notification data frame through the physical layer of the radio link transceiver, check the session maintenance timeout completion notification data frame by the data link layer, and store the session maintenance timeout completion notification data frame by the base station controller.

4. ZH0 and GD1 synchronous transmission session maintenance timeout end notification

After ZH0 receives the session maintenance overtime end notification data frame, the frame is forwarded by the base station controller in a routing way, the link layer of the wireless link transceiver checks the session maintenance overtime end notification data frame, the physical layer performs channel coding on the session maintenance overtime end notification data frame, and then the frame is sent out in the downlink time slot DS1 of the wireless link, and XL4, GD1 and GD3 can all be received.

After receiving the session maintenance overtime end notification data frame, the GD1 transmits the session maintenance overtime end notification data frame through a base station controller router, and a link layer of the wireless link transceiver checks the session maintenance overtime end notification data frame, and a physical layer performs channel coding on the session maintenance overtime end notification data frame, and then sends out the session maintenance overtime end notification data frame in a downlink time slot DS3 of the wireless link, wherein XL4, ZH0 and GD2 can all be received.

5. XL4, ZH0, GD1, GD2, and GD3 instant-issue session maintenance timeout end notification

After receiving the session maintenance timeout end notification data frame, all the base stations determine whether forwarding is required on a downlink time slot or an uplink time slot of the wireless link according to session information. The judgment principle is as follows: and the base station is in the session and forwards, and the base station is not in the session and does not forward.

The invention provides an optimized simulcast signal transmission method, which adopts uplink multipath uploading and downlink preferential forwarding methods, ensures that a user communication terminal achieves an optimal receiving effect, and avoids discontinuous or interrupted conversation caused by high dynamic property of an application scene.

The invention can solve the problems of discontinuous conversation and even interruption of conversation caused by the non-ideal conversation effect of the high dynamic environment through the optimized forwarding rule of the link channel and the access channel.

The optimized simulcast signal transmission method can be used for self-adaptive wireless link simulcast systems in the scenes of earthquake relief, emergency, safety guarantee and the like.

Those skilled in the art will appreciate that all or part of the flow of the methods of the embodiments described above may be accomplished by way of a computer program to instruct associated hardware, where the program may be stored on a computer readable storage medium. Wherein the computer readable storage medium is a magnetic disk, an optical disk, a read-only memory or a random access memory, etc.

The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.

Claims

1. A method for simulcast signal transmission, comprising:

sequentially arranging command center ZH0 communication vehicles, fixed-position communication vehicles GD1, GD2, … and GDN-1 at the edge position of an ad hoc network area, wherein a command center base station is arranged on the command center ZH0 communication vehicles, and the fixed-position communication vehicles GD1, GD2, … and GDN-1 are respectively provided with a first base station, a second base station, …, an N-1 base station and a motor patrol communication vehicle XLN;

distributing a link time slot to the command center base station, the first base station and the Nth base station;

performing simulcast signal transmission through the user communication terminal and each base station, wherein performing simulcast signal transmission through the user communication terminal and each base station includes:

receiving, by a first neighboring base station, a signal sent from the user communication terminal and sending a preferred signal from a downlink slot of the first neighboring base station, wherein the first neighboring base station is the command center base station, a plurality of base stations adjacent to the user communication terminal from among the first base station to the nth base station; and

and receiving the preferred signals through the command center base station and the downlink time slots of the wireless access channels from the first base station to the Nth base station, comparing the signal quality of a plurality of preferred signals and forwarding the preferred signals according to the comparison result.

2. The simulcast signal transmission method of claim 1, wherein allocating link timeslots to the command center base station, the first base station, and the nth base station comprises:

sequentially allocating N downlink time slots to the command center base station, the first base station, the second base station and the N-1 base station according to …; and

and selecting 1 or 2 base stations with the best signal quality from the occupied N downlink time slots by the N-th base station as a previous-hop base station, and then applying for the uplink time slots from the previous-hop base station in a random access mode.

3. The simulcast signal transmission method of claim 1, wherein performing the simulcast signal transmission through the user communication terminal and the respective base stations comprises: session establishment phase, session phase and session end phase, wherein,

initiating a session request in the session establishment phase or session data in the session phase through the user communication terminal;

receiving and storing the session request in a session establishment phase or the session data in the session phase by the first neighboring base station;

synchronizing a session request in the session establishment stage or receiving and storing the session data in a multipath manner in the session stage through the command center base station, the first base station and the Nth base station;

The first adjacent base station is used for optimizing the session request response in the session establishment phase, or the command center base station, the first base station and the N base station synchronously transmit the session request response in the session establishment phase or the stored multipath session data are optimized and transmitted in the session phase; and

actively initiating a session ending request at the session ending stage through the user communication terminal; and the Nth base station transmits a session maintenance overtime ending notification in the session ending stage.

4. The simulcast signaling method of claim 3, wherein the nth base station session maintenance timeout end notification comprises:

when the Nth base station performs a session state, starting a session maintenance timeout timer, and judging that the session maintenance is overtime when a session data frame is not received before the session maintenance timeout timer is overtime;

transmitting a session maintenance timeout end notification data frame in a downlink slot through the nth base station; and receiving and storing the session maintenance timeout end notification data frame by a second neighboring base station, wherein the second neighboring base station is neighboring the nth base station, and wherein the first neighboring base station comprises the second neighboring base station and the nth base station;

Synchronously transmitting the session maintenance overtime ending notification data frame in a downlink time slot of a wireless link through the second adjacent base station; and

and after receiving the session maintenance overtime end notification data frame, judging whether to forward the session maintenance overtime end notification data frame in an uplink time slot or a downlink time slot of a wireless link according to a session information judging rule by the command center base station, the first base station and the N-1 base station, wherein the session information judging rule comprises that the base station forwards when in a session stage and does not forward when in the session end stage.

5. A simulcast signal transmission method according to claim 3, wherein performing the simulcast signal transmission via the user communication terminal and the respective base station comprises:

generating a session establishment request data frame through the user communication terminal, checking the session establishment request data frame, carrying out channel coding on the session establishment request data frame, and then sending the session establishment request data frame in an uplink time slot of a wireless access channel according to a random access rule;

channel decoding is carried out on the received session establishment request data frame through the first adjacent base station, the session establishment request data frame is checked, and the session establishment request data frame is stored in a multipath mode;

And transmitting the received session establishment request data frame in a corresponding wireless link time slot through the first adjacent base station, so that each of the command center base station, the first base station and the Nth base station receives the session establishment request data frame from at least one base station in the first adjacent base station.

6. The simulcast signal transmission method of claim 5, wherein performing the simulcast signal transmission through the user communication terminal and the respective base stations comprises:

comparing the received session establishment request data frames through the command center base station, the first base station and the Nth base station, and selecting the Nth base station with the best signal quality to send a session request response data frame; and

and transmitting the received session request response data frame through the corresponding wireless link time slot by the second adjacent base station, so that each of the command center base station, the first base station and the N base station transmits the session request response data frame according to the principle of optimal signal quality.

7. A simulcast signal transmission method according to claim 3, wherein performing the simulcast signal transmission via the user communication terminal and the respective base station comprises:

Generating a session data frame through the user communication terminal, checking the session data frame, encoding the session data frame which passes the checking, and then transmitting the session data frame in an uplink time slot of a wireless access channel;

channel decoding and checking are carried out on the received session data frames through the first adjacent base station, and then the session data frames which pass the checking are stored in a multipath mode;

transmitting the session data frame through each base station in the first adjacent base stations through a wireless link time slot, and receiving the session data frame from at least one base station in the first adjacent base stations and storing the session data frame in multiple ways by the command center base station and each base station from the first base station to the Nth base station; and

and comparing the signal quality of the stored multipath session data frames through the command center base station, the first base station and the N-th base station, and broadcasting the session data frames with the optimal signal quality in corresponding link time slots.

8. A simulcast signal transmission apparatus, comprising:

the method comprises the steps of sequentially arranging a command center ZH0 communication car, fixed-position communication cars GD1, GD2, … and GDN-1 at the edge position of an ad hoc network area and enabling distances between adjacent communication cars to be equal, wherein the command center ZH0 communication car is provided with a command center base station, the fixed-position communication cars GD1, GD2, … and GDN-1 are respectively provided with a first base station, a second base station, …, an N-1 base station and an N base station of a motor patrol communication car XLN;

The time slot allocation module is used for allocating a link time slot to the command center base station, the first base station and the N base station;

the simulcast signal transmission module is used for executing simulcast signal transmission through the user communication terminal and each base station, and comprises an uplink multipath uploading module and a downlink preferential forwarding module,

the uplink multipath uploading module is configured to receive, by using a first neighboring base station, a signal sent from the user communication terminal and send a preferred signal from a downlink timeslot of the first neighboring base station, where the first neighboring base station is the command center base station, and a plurality of base stations from the first base station to the nth base station, which are adjacent to the user communication terminal; and

the downlink preferred forwarding module is configured to receive the preferred signals through downlink timeslots of wireless access channels from the command center base station, the first base station, and the nth base station, compare signal qualities of a plurality of preferred signals, and forward the preferred signals according to a comparison result.

9. The simulcast signal transmission apparatus of claim 8, wherein the time slot allocation module:

For sequentially allocating N downlink time slots to the command center base station, the first base station, the second base station, …, the N-1 th base station; and

and the N base station selects 1 or 2 base stations with the best signal quality from the occupied N downlink time slots as the last-hop base station, and then applies for the uplink time slots from the last-hop base station in a random access mode.

10. The simulcast signal transmission apparatus of claim 8, wherein each of the command center base station, the first base station, and the nth base station comprises: a base station controller signal processing module, a wireless access channel receiving module, a wireless link channel transmitting module, a wireless link channel receiving module and a wireless access channel generating module, wherein,

the wireless access channel receiving module is used for decoding and receiving signal data frames sent by the user communication terminal through a physical layer channel, checking the signal data frames through a data link layer, synchronously numbering the checked signal data frames, filling the signal data frame numbers SDN, and then transmitting the signal data frames to the base station controller signal processing module;

The base station controller signal processing module is configured to perform uplink data processing and downlink data processing, where the uplink data processing is configured to, after receiving a signal data frame from the radio access channel receiving module and filling a source base station number BSN and a radio access forwarding time slot number FSN into the received signal data frame, determine which signal data frame is sent in a downlink time slot according to signal quality of multiple paths of signal data; the downlink data processing is used for optimizing according to the signal quality after receiving the signal data of the uplink time slot of the wireless access channel and the signal data of each time slot of the wireless link channel, and transmitting the optimized signal to the wireless access channel transmitting module before the wireless access forwarding time slot number TSN;

the wireless link channel transmitting module is used for receiving the signal data sent by the base station controller signal processing module, transmitting the signal data to a data link layer, and transmitting the signal data to other previous-hop base stations and next-hop base stations after channel coding of a physical layer;

the wireless link channel receiving module is used for decoding and receiving signal data of each time slot of the wireless link through a physical layer channel, checking through a data link layer and immediately transmitting the signal data to the base station controller signal processing module after the checking;

The wireless access channel transmitting module is used for extracting the wireless access forwarding time slot number TSN in the signal data frame after receiving the signal data of the base station controller signal processing module, and transmitting the effective signal data to the user communication terminal after carrying out channel coding on the effective signal data by synchronous control.