WO2010102552A1

WO2010102552A1 - Audio video wireless transmission system and transmission method

Info

Publication number: WO2010102552A1
Application number: PCT/CN2010/070927
Authority: WO
Inventors: 刘化文
Original assignee: 深圳市源富创新电子有限公司
Priority date: 2009-03-09
Filing date: 2010-03-09
Publication date: 2010-09-16
Also published as: CN101500131A; CN101500131B

Abstract

An audio video wireless transmission system and transmission method are disclosed in the present invention. The system includes a wireless audio video center station and a wireless audio video mobile terminal. When the wireless audio video center station and the wireless audio video mobile terminal adopt a Wireless Local Area Network (WLAN) transmission channel to perform audio video wireless transmission, the wireless audio video center station detects in real-time the quality of the signal delivered from the wireless audio video mobile terminal, and the wireless audio video center station and the wireless audio video mobile terminal initiate a multi-carrier transmission channel when the quality of the signal decreases to a warning value, and a picture of the center station is also switched to the multi-carrier transmission channel synchronously. The WLAN transmission channel is kept on monitoring, and a WLAN transmission channel interface is recovered and the multi-carrier transmission channel is cut off when the quality of the signal of the WLAN transmission channel increases to a predetermined value. The present invention integrates the WLAN scheme with the multi-carrier scheme together, so as to realize the sufficient utilization under various resource situations, and to reliably realize audio video real-time transmission and data real-time transmission in a complex environment.

Description

Audio and video wireless transmission system and transmission method

Technical field

The invention relates to a wireless signal transmission technology, in particular to an audio and video wireless transmission scheme.

Background technique

At present, with the development of cities and the density of buildings, the safety of high-rise buildings and underground garages and shopping malls has become a communication security problem in fire protection and emergency response; in complex environments, such as multi-level underground garages or urban villages, handshakes, abnormal situations At the time, how to know the actual situation inside, this also puts forward the requirements of real-time video surveillance program for communication security. Especially in the event of a fire in an underground shopping mall or garage, how to effectively communicate and dispatch firefighters has always been a difficult problem in the field of wireless communications. In the event of a fire, the original communication network (wired telephone, indoor coverage wireless system) is completely unusable. The walkie-talkie system can only reach the communication distance of the underground one. When the second or third floor is underground, only the manual intercom and talk mode can be used for simple communication. The efficiency is low and the effect is poor. For the disaster-saving and disaster relief of “seconds and seconds”, the task Quick completion or firefighter's own safety is especially important. In particular, the return of the live video and the two-way intercom, it is convenient for the commander on the command vehicle to carry out comprehensive coordinated command and dispatch, complete the task quickly, and ensure the safety of the firefighter. It has always been an urgent problem for the communication industry.

technical problem

The main object of the present invention is to provide an audio and video wireless transmission system and a transmission method for realizing reliable transmission in a complex environment.

Technical solution

To this end, the present invention proposes an audio and video wireless transmission system, including a wireless audio and video central station and a wireless audio and video mobile terminal; when the WLAN transmission channel is used for wireless transmission of audio and video, the wireless audio and video central station detects the wireless device in real time. The quality of the signal transmitted by the audio and video mobile terminal, when the signal quality drops to the warning value, both enable the multi-carrier transmission channel, and the central station picture also switches to the multi-carrier transmission channel synchronously; the WLAN transmission channel keeps listening, when the signal of the WLAN transmission channel After the quality rises to a predetermined value, the interface is restored to the WLAN transmission channel, and the multi-carrier transmission channel is cut off.

The above-mentioned audio and video wireless transmission system further includes a wireless audio and video intelligent relay station, and adopts a relay mode for the WLAN transmission channel to realize bidirectional transmission of multi-level signals. The wireless audio and video relay station includes a WLAN transmission module and a voice intercom module; the voice intercom module is connected to the WLAN transmission module.

In the above audio and video wireless transmission system, the wireless audio and video mobile terminal comprises a camera, an earphone, a microphone and an automatic power control transmitter, and the camera, the earphone and the microphone are respectively connected with an automatic power control transmitter; the automatic power control transmission The machine comprises a baseband processing module, a WLAN transmission module, a multi-carrier transmission module and a voice intercom module; the baseband module performs automatic adjustment of the camera and encoding compression and decompression of the audio and video signals, and is adopted by the WLAN transmission module or the multi-carrier transmission module. The antenna is transmitted, and the voice intercom module is configured to transmit a voice signal and enable a control signal of the WLAN transmission module or the multi-carrier audio and video transmission module.

In the above audio and video wireless transmission system, the wireless audio and video central station includes a wireless audio and video transmission device and a monitoring computer; the wireless audio and video transmission device includes a WLAN transmission module, a multi-carrier audio and video transmission module, a voice intercom module, and a video. a server module; the multi-carrier transmission module and the voice intercom module are connected to the WLAN transmission module by using the video server module, and the video server module is configured to collect and convert a video signal of the multi-carrier transmission module; the WLAN transmission module The output is connected to the monitoring computer.

Meanwhile, the present invention proposes an audio and video wireless transmission method. When a WLAN transmission channel is used for wireless transmission of audio and video, the wireless audio and video central station detects the quality of the signal transmitted from the mobile terminal in real time, when the signal quality drops to the warning value. When the multi-carrier transmission channel is enabled, the central station picture is also switched to the multi-carrier transmission channel synchronously; the WLAN transmission channel remains monitored, and when the signal quality of the WLAN transmission channel rises to a predetermined value, the interface is restored to the WLAN transmission channel interface, and the multi-carrier transmission channel is cut off.

In the above audio and video wireless transmission method, the WLAN transmission channel adopts a relay mode to realize bidirectional transmission of multi-level signals.

The above-mentioned audio and video wireless transmission scheme, when the image transmission enables the multi-carrier transmission channel, the multi-carrier transmission channel completes the uplink transmission of the video and the sound; the voice intercom transmission channel issues the control command to the mobile terminal, and realizes the downlink transmission of the voice .

In the above audio and video wireless transmission method, the signal collected by the multi-carrier transmission channel is converted into data conforming to the TCP/IP protocol and transmitted to the central station.

In the above audio and video wireless transmission method, when the signal quality transmitted by the WLAN transmission channel drops to an early warning value, the WLAN channel is switched to the multi-carrier transmission channel, and if the handover is not successful after the predetermined time, the voice intercom channel is switched. .

The invention adopts two modes of multi-carrier coding orthogonal frequency division multiplexing COFDM mode and WLAN mode, and can automatically switch between the two modes, thereby achieving reliable, convenient and efficient transmission purposes; multi-carrier COFDM mode can bring video The signal is transmitted farther than the conventional communication method, the signal penetration ability is stronger, and the effective signal transmission can be performed in a complicated environment, for example, the underground garage can also reach the negative one or the negative two layers.

Further, the WLAN transmission adopts a multi-level relay mode to realize bidirectional transmission of multi-level signals, and is compatible with multi-carrier mode intelligent switching, thereby enabling more efficient and reliable transmission, for example, a three-storey, four-layer or more underground garage can be realized. Or the building includes efficient transmission of audio signals, video signals and data signals.

Since the invention adopts the wireless transmission mode to realize the transmission of the complex environment, the pipeline is not required to be flexible and maneuverable. The automatic matching connection of the equipment in the system is available, without complicated presets, especially for emergency applications; by default, the system can be quickly put into use without re-setting, to win time for disaster relief and emergency response;

If the invention is applied to fire emergency rescue, firefighters outside the fire zone can obtain real-time images through the invention, and the two-way language function in the system can replace the walkie-talkie of the firefighter, realizes blind zone communication, and can realize scientific dispatch and support. According to the actual situation, the fire-fighting plan and rescue sequence will be deployed in time, and the firefighters can organize the rescue in time to prevent the firefighters from being safe.

In addition, based on the characteristics of strong liquidity of the system, fixed-point monitoring of some specific building basements, tunnels, entrances and exits, and monitoring locations can be changed at any time according to actual needs. This system is not open wireless network (2G, 3G, WiFi). Wait) And complex environments that are unfavorable for wireless communication (such as basement and urban villages) Monitoring, disaster relief provides a simple, fast and very convenient solution. If this system is used in conjunction with automatic search for robots and remote-controlled helicopters, it can be used for on-site monitoring or simple rescue work for dangerous situations where catastrophic and unfavorable people go.

By applying the solution of the invention, if the recording device is combined with the recording device, the fire cause analysis and the fire rescue plan optimization can be performed afterwards, and the whole process can be performed for image, language communication, storage, deletion, editing and playback; and the Internet can be connected at the same time, Contact with a higher level command center; multiple points of monitoring can be performed simultaneously.

Beneficial effect

The system of the present invention, Wide range of applications, can be applied to public security, fire, traffic police, civil air defense, urban management law enforcement, environmental monitoring, fire emergency, water conservancy, electric power rescue, railway rescue, maritime law enforcement, sea surveillance inspection, customs border defense, dock monitoring, forest fire prevention, Oilfield anti-theft, military reconnaissance, television broadcast, etc., suitable for real-time mobile transmission and monitoring of high-quality images in a variety of complex environments such as urban, offshore and mountainous.

DRAWINGS

FIG. 1 is a schematic structural diagram of a system according to Embodiment 1 of the present invention.

FIG. 2 is a schematic structural diagram of a central station according to Embodiment 1 of the present invention.

FIG. 3 is a schematic structural diagram of a mobile terminal according to Embodiment 1 of the present invention.

4 is a schematic structural diagram of a wireless audio and video intelligent relay station (wireless audio and video transmission device) according to Embodiment 1 of the present invention.

FIG. 5 is a schematic structural diagram of a wireless audio and video intelligent relay station according to Embodiment 3 of the present invention.

Embodiments of the invention

The present invention will be further described in detail below through the specific embodiments and the accompanying drawings.

Embodiment 1

Please refer to FIG. 1 , the audio and video wireless transmission system of this example includes a wireless audio and video central station, a wireless audio and video intelligent relay station, and a wireless audio and video mobile terminal.

The wireless audio and video center station includes a semi-fixed detachable parabolic antenna, a front antenna amplifier, a feeder, a wireless audio and video transmission device, a monitoring computer, and a two-way intercom device. Please refer to FIG. 2, the wireless audio and video transmission device includes a WLAN transmission module, and the actual working frequency band thereof may be an improved version based on WLAN of 1.2 GHz, 2.4 GHz, 5.8 GHz or 700 to 900 MHz; a multi-carrier transmission module, the actual The working frequency band can be 300-800MHz, similar to the current single-video video communication terminal module. For convenience of description, the following is a typical representative of 340MHz; the voice intercom module can adopt the traditional 350MHz-520MHz voice intercom function module, for convenience of description, The latter is exemplified by 340MHz; the video server module is used to collect and convert the video signal of the multi-carrier transmission module.

The 2.4 GHz WLAN transmission module is connected to the monitoring computer through the RJ45 network interface to complete the transmission of images and voice. The 340MHz multi-carrier transmission module and the 370MHz voice intercom module are all connected to the TCP/IP-based network interface and controlled by the monitoring computer. The control command of the 370MHz voice intercom module operates through the serial port; the AV signal from the 340MHz multi-carrier transmission module is transferred to the TCP/IP protocol through the video server module and transmitted to the 2.4GHz module. The control signal from the monitoring computer is also Control the 370MHz downlink command through the serial port. Microphones and headphones can also be taken directly from the monitoring computer.

Wireless audio and video mobile terminal: Please refer to Figure 3, including head-mounted infrared auto-aperture autofocus camera, throat generator, integrated headphone microphone, automatic power control transmitter and high-gain built-in small size antenna. The automatic power control transmitter includes: a baseband processing module, which completes the camera automatic aperture speed and night vision adjustment and video signal compression, vocoding compression and decompression, realizes two-way transmission of digital voice; WLAN transmission module, its actual working frequency band It may be an improved version of WLAN based on 1.2 GHz, 2.4 GHz, 5.8 GHz or 700-900 MHz; the multi-carrier transmission module may have a working frequency band of 300 to 800 MHz, similar to the current individual video communication terminal module; a voice intercom module, The traditional 350MHz ~ 520MHz voice intercom function module.

The wireless audio and video mobile terminal is light in structure and convenient to use, and can be installed on a motor vehicle or hung in the waist of the rescuer to completely liberate the human hand; the collected audio/video signal is wirelessly transmitted to the wireless audio and video intelligent relay station. It can penetrate a floor and two walls inside the building; the built-in rechargeable Ni-MH battery can last up to 6 hours; the infrared camera can capture clear even in dark and dark conditions. Information, fully meet the needs of the rescue site. Built-in high-gain omnidirectional antenna for optimum results in the widest range. The camera's lens features auto iris, auto focus, and automatic white level processing for shock and high temperature resistance.

In this example, the WLAN transmission module is used to implement non-destructive relaying of multi-level WLAN points; the multi-level WLAN is compatible with multi-carrier audio and video transmission, and the voice intercom module supplements the reverse speech in this mode, so that the system realizes two-way Voice transmission function; realize on-demand switching, adapt to the specific requirements of different application environments, automatically select the best mode to complete the task when the frequency resource is scarce or the environment is not allowed.

In the case of line-of-sight conditions or microwave attenuation is not serious, the system uses a 2.4 GHz WLAN transmission module for direct two-way communication, adding a relay station to complete the signal connection in the case of multi-layer corner blocking. The wireless audio and video center station monitors and detects that the 2.4GHz signal quality drops to a certain extent, and the available bandwidth is less than 300kbps (equivalent to 10fps, which can be set by the user). The voice intercom module remotely activates the 340MHz channel of the wireless audio and video mobile terminal. The carrier transmission module performs the main service switching. The realization of the process is also possible for the operator to actively intervene to switch from the background display to the foreground display after the 340MHz image is stably transmitted. In the operator's view, the image is suddenly and fast when the 2.4GHz image becomes slow (when switching to the 340MHz mode) ), the image is continuous, and there is no sense of switching. In fact, the two systems work at the same time for a period of time, but the image effect is good and switched to the foreground so that the user can see it.

When the image is switched to the 340MHz main channel, the video and audio uplink transmission is completed by the multi-carrier transmission channel, and the channel of the 370MHz voice intercom module is used as the voice channel for receiving the command command, and the channel can also be used as the voice scheduling of the multi-user. The function is equivalent to the walkie-talkie. The implementation can be implemented by using the off-the-shelf walkie-talkie module or the multi-carrier transmission module of the 340MHz channel.

At this time, the 2.4GHz channel has been waiting for monitoring. When the signal quality rises to a certain level (such as 20fps) and continues for a certain period of time (such as 5 seconds), the system automatically switches the current channel to the 2.4GHz channel, and remotely turns off the wireless audio and video. The multi-carrier transmission channel of the mobile terminal, that is, restored to the 2.4 GHz mode, reduces collisions with other systems.

The working principle of system switching is further described below. Under normal conditions, the 2.4GHz operation, the wireless audio and video center station detects the signal quality from the mobile station in real time, and monitors the refresh rate of the video image. When the signal drops to a certain level, the 340MHz multi-carrier audio and video transmission module system is turned on. The picture is also switched to the 340MHz channel simultaneously; the 2.4GHz channel is still trying to work, when the 2.4GHz signal quality rises to the available effect and continues to a period of time to return to the 2.4GHz channel interface, cut off the 340MHz channel.

In the wireless audio and video mobile terminal, when attempting to communicate with 2.4GHz is unsuccessful or the signal quality is too poor, the 340MHz channel and the central station will be actively activated; or the 2.4GHz channel of the central station controls the switching of its state, and the 370MHz always waits, actually It only needs the receiving function of the 370MHz channel, so it is always in the waiting state.

The 2.4GHz channel of the central station is always on, searching for signals from the mobile terminal; the 340MHz channel is always on in the waiting channel; the 370MHz channel sends signals (voice and control commands) on demand. When the 2.4 GHz signal falls, when the transmission speed drops to a certain extent, the command is switched by the 2.4 GHz channel, and if it is not successful, the command is switched by the 370 MHz channel after a certain time. The change of parameters is automatically recognized and operated by the monitoring computer, and they all run automatically, while retaining human intervention. The 370MHz channel transmits signals only when the central station attendant speaks and when there is a 370MHz command (mainly supplemented by 2.4GHz).

At the same time, in the 2.4GHz channel, multiple remote switching quantities and analog quantities (converted into digital quantities) can be supported, which facilitates expansion of other applications, such as temperature and humidity acquisition, water valve control, and can be achieved with little increase in cost. Function, to achieve channel acquisition and control, unified monitoring by the central station.

The following describes the process of switching from the perspective of software control. When it is judged that the number of 2.4 GHz image frames reaches the set value, the 2.4 GHz channel is kept working. When the signal quality is degraded and the image refresh rate drops to the set value, the remote control is turned on. The 340MHz transmission channel scans the image signal at the center end. After receiving the 340MHz channel image, it automatically switches off the 2.4GHz channel image display, and the main interface displays the 340MHz channel image.

At this time, 2.4GHz is still continuously monitoring its signal quality. When the number of image frames reaches the set value and continues for a period of time (such as 5 seconds, it can be set), it switches back to the 2.4GHz channel, and the central station remotely turns off the 340MHz transmission. These switches are performed in the background, and people do not feel the pause of the video visually.

The 370MHz channel is mainly used to solve the downlink voice transmission and data commands; the one-way voice receiving module can be used, and the most basic and necessary commands are only one: when the 2.4GHz suddenly loses contact, the channel can be turned on by 340MHz, although usually Switching when the 2.4 GHz signal slowly drops.

Embodiment 2

On the basis of the first embodiment, a software-implemented spread-spectrum remote transceiver sub-module is embedded in the wireless audio and video central station, the wireless audio and video intelligent relay station and the wireless audio and video mobile terminal, respectively, for transmitting signals to the building port. Use when the vehicle is used (if the command vehicle cannot drive to the vicinity of the target building). The command vehicle from the second floor to the ground and 1,500 meters to 4,000 meters away from the exit (without obstruction) can receive high quality pictures as described in the system characteristics, and the intelligent relay station is also the reception of the wireless audio and video center station. end.

Embodiment 3

Referring to FIG. 5, the difference between this example and the first embodiment is that the wireless audio and video intelligent relay station of this example does not include a multi-carrier transmission module, and therefore, it only relays WLAN transmission and voice intercom transmission. .

The above is a further detailed description of the present invention in connection with the specific preferred embodiments, and the specific embodiments of the present invention are not limited to the description. It will be apparent to those skilled in the art that the present invention may be made without departing from the spirit and scope of the invention. For example, the 370MHz can also be extended by the system using the repeater solution, continuing the usage habits of the prior art, and compatible with conventional ultrashort wave walkie-talkie systems. 340MHz is one-way transmission of voice and image to the central station, reverse voice transmission is implemented by 370MHz, mainly because 370MHz is a mature walkie-talkie solution, low price and stable performance. Of course, the object of the present invention can be fully achieved by using two sets of 340 MHz schemes. Here, a simple explanation is also needed. In the above description, 340MHz refers to a COFDM one-way audio and video transmission channel of 210MHz to 860MHz. For convenience of description, it is abbreviated as 340MHz. Similarly, a 370MHz channel refers to a voice intercom channel of 320MHz to 470MHz. For convenience of description, referred to as 370MHz channel; 2.4GHz channel, its actual working frequency band can be 1.2GHz, 2.4GHz, 5.8GHz or 700-900MHz WLAN-based improved version.

Claims

An audio and video wireless transmission system, including a wireless audio and video central station and a wireless audio and video mobile terminal; when the two use the WLAN transmission channel for audio and video wireless transmission, the wireless audio and video central station detects the real-time transmission from the wireless audio and video mobile terminal. Signal quality, when the signal quality drops to the warning value, both enable the multi-carrier transmission channel, and the central station picture also switches to the multi-carrier transmission channel synchronously; the WLAN transmission channel keeps listening, when the signal quality of the WLAN transmission channel rises to a predetermined value, Restore to the WLAN transmission channel interface and cut off the multi-carrier transmission channel.
The audio/video wireless transmission system according to claim 1, further comprising: a wireless audio and video intelligent relay station, wherein the WLAN transmission channel adopts a relay mode to realize bidirectional transmission of the multilevel signal.
The audio-video wireless transmission system according to claim 1, wherein said wireless audio-video mobile terminal comprises a camera, an earphone, a microphone and an automatic power control transmitter, said camera, the earphone and the microphone respectively transmitting with automatic power control The automatic power control transmitter includes a baseband processing module, a WLAN transmission module, a multi-carrier transmission module, and a voice intercom module; the baseband module performs automatic adjustment of the camera and encoding compression and decompression of the audio and video signals, and the WLAN is A transmission module or a multi-carrier transmission module is transmitted through the antenna, and the voice intercom module is configured to transmit a voice signal and enable a control signal of the WLAN transmission module or the multi-carrier audio and video transmission module.
The audio/video wireless transmission system according to claim 1, wherein said wireless audio and video central station comprises a wireless audio and video transmission device and a monitoring computer; said wireless audio and video transmission device comprises a WLAN transmission module and a multicarrier transmission module The voice intercom module and the video server module; the multi-carrier transmission module and the voice intercom module are connected to the WLAN transmission module by using the video server module, and the video server module is configured to collect and convert the video of the multi-carrier transmission module. a signal; the WLAN transmission module output is connected to the monitoring computer.
The audio/video wireless transmission system according to claim 2, wherein the wireless audio and video relay station comprises a WLAN transmission module and a voice intercom module; and the voice intercom module is connected to the WLAN transmission module.
A method for wireless transmission of audio and video, when a WLAN transmission channel is used for wireless transmission of audio and video, the wireless audio and video central station detects the quality of the signal transmitted from the mobile terminal in real time, and enables the multi-carrier transmission channel when the signal quality drops to the warning value. The central station picture is also switched to the multi-carrier transmission channel synchronously; the WLAN transmission channel keeps listening, and when the signal quality of the WLAN transmission channel rises to a predetermined value, the interface is restored to the WLAN transmission channel interface, and the multi-carrier transmission channel is cut off.
The audio and video wireless transmission method according to claim 6, wherein the WLAN transmission channel adopts a relay mode to realize bidirectional transmission of multi-level signals.
The audio/video wireless transmission scheme according to claim 6, wherein when the multi-carrier transmission channel is enabled, the uplink transmission of the video and the sound is completed by the multi-carrier transmission channel; and the control command is sent to the mobile terminal by the voice intercom transmission channel. And realize the downlink transmission of voice.
The audio and video wireless transmission method according to claim 6, wherein the signal received by the central station and collected by the multi-carrier transmission channel is converted into a data transmission conforming to the TCP/IP protocol.
The audio/video wireless transmission method according to claim 6, wherein when the signal quality transmitted by the WLAN transmission channel drops to an early warning value, the WLAN transmission channel is switched to the multi-carrier transmission channel, and if the predetermined time is not switched, If successful, the voice intercom channel is switched.