CN110572196B

CN110572196B - Wireless virtual reality system based on distributed antenna

Info

Publication number: CN110572196B
Application number: CN201910809798.7A
Authority: CN
Inventors: 王旭; 陈南希
Original assignee: Shanghai Institute of Microsystem and Information Technology of CAS
Current assignee: Shanghai Institute of Microsystem and Information Technology of CAS
Priority date: 2019-08-29
Filing date: 2019-08-29
Publication date: 2023-07-18
Anticipated expiration: 2039-08-29
Also published as: CN110572196A

Abstract

The invention relates to a wireless virtual reality system based on a distributed antenna, which comprises a host and a helmet, wherein the host comprises 8 remote radio units. The 8 remote radio units are respectively in two different working modes, wherein 1 remote radio unit sends high-definition video and high-fidelity audio to the helmet; while the other 7 wheels of the remote radio unit transmit channel detection signals to the helmet. When an obstacle appears between one of the remote radio units and the helmet, the remote radio units can be quickly switched to other remote radio units, so that the signal shielding problem can be effectively solved, and high-speed data transmission between the host and the helmet is ensured. In addition, the remote radio unit adopts an analog beam forming technology, the helmet adopts a hybrid analog/digital beam forming technology, and the radio frequency channel for receiving the channel detection signal adopts a low-precision analog-to-digital converter, so that the hardware complexity and the power consumption of the system can be effectively reduced.

Description

Wireless virtual reality system based on distributed antenna

Technical Field

The invention relates to the field of virtual reality, in particular to a wireless virtual reality system based on a distributed antenna.

Background

With the continuous progress of computer science, man-machine interaction technology has also been rapidly developed. In the early DOS command line environment, the user could only use a keyboard to enter commands. In the microsoft windows operating system, the user can operate through a mouse. Whereas in smartphones popular in recent years, both the android system and the apple iOS system allow users to operate directly through a touch screen. In these systems, the display devices are based on a two-dimensional plane, although the user's operation is becoming simpler and more convenient. In practice, people live in a three-dimensional space. There are various limitations to describing objects in three dimensions using two-dimensional planes. In recent years, virtual reality technology has been rapidly developed. The virtual reality technology can directly show the three-dimensional space to the user, so that man-machine interaction is completed in a mode which accords with daily living habits of people. In a virtual reality system, a user needs to wear a virtual reality helmet to receive information sent from a host computer, thereby experiencing a virtual world that is completely emulated by the computer.

Unlike the conventional computer, in order to enable the user to complete man-machine interaction using the same body posture as in daily life, the computing unit and the display unit of the virtual reality system are located at different positions in the physical space. This results in an important problem: how the results of the calculation unit are passed to the display unit. One possible way is to use a cable such as HDMI, DP, USB to transmit data by referring to the conventional computer, which has the advantage of ensuring high-speed and reliable data transmission, and has the disadvantage that a user drags a physical line behind the helmet to connect with the host computer when using the virtual reality system. This cable limits the range of motion of the user and may become entangled or stumbled with the user as the user moves.

Wireless virtual reality systems utilize wireless communication technology to transfer data from a host to a helmet. Because the cable is not bound, the user can freely move and perform various complex man-machine interactions, thereby obviously improving the user experience. The virtual reality system needs to transmit high-definition video, and has high requirement on bandwidth. The bandwidth of the millimeter wave frequency band is large, and the data transmission rate is high. Therefore, the wireless virtual reality system generally adopts millimeter wave frequency band for data transmission. An important disadvantage of millimeter wave communication is the short wavelength and poor diffraction ability when encountering obstacles. In the case of a direct path, millimeter wave communication can provide a sufficient transmission speed for transmission of high definition video. However, in the case where there is an obstacle between the host computer and the helmet, the transmission speed of millimeter wave communication may drastically decrease. For example, during use of the virtual reality system, the user may inadvertently block wireless signals due to movement of the head, arms, or other parts of the body. In addition, if a plurality of users use the virtual reality system at the same time, the situation that the different users are blocked by each other is unavoidable. If a wireless signal is transmitted from a fixed location, the location of the transmitting antenna is not always selected, and it is not guaranteed that the signal shielding phenomenon can be completely avoided.

The patent application number 201710085582.1 provides a wireless virtual reality system, which can compress video data and then carry out wireless transmission, and can reduce the requirement of the virtual reality system on the wireless transmission rate by reducing the data volume. However, this approach has the disadvantage that: on the one hand, video compression can reduce the quality of video, thereby affecting user experience; on the other hand, the compression and decompression of the video are both large in calculation amount, which increases the power consumption of the virtual reality helmet, and for the virtual reality helmet powered by the battery, the increase of the power consumption shortens the service time of the virtual reality system, so that the user experience is affected. In addition, the virtual reality system has a severe requirement on delay, and the compression of the video at the transmitting end and the decompression of the video at the receiving end inevitably consume a certain time, which increases the delay of the system, thereby causing dizziness when a user wears the virtual reality helmet.

Disclosure of Invention

The invention provides a wireless virtual reality system based on a distributed antenna, which comprises a host and a helmet, wherein the host is connected with the helmet; the host comprises 8 remote radio units which are respectively arranged at 8 vertexes of a room; the 1 radio remote unit is used for sending high-definition video and high-fidelity audio to the helmet; while the other 7 wheels of the remote radio unit transmit channel detection signals to the helmet.

In the invention, the host computer is provided with a remote radio unit at each of 8 vertexes of the room. If an obstacle exists between one remote radio unit and the helmet, the remote radio unit can be switched to communicate with the helmet. As the radio remote units are arranged at all the vertexes of the room, the direct path exists between at least one radio remote unit and the helmet, and high-speed data transmission can be performed.

Further, the host also comprises 1 baseband unit and 1 upper layer protocol unit; the 8 remote radio units of the host share 1 baseband unit and 1 upper layer protocol unit; the baseband unit is used for processing baseband signals, and the upper protocol unit is used for processing all communication protocols above a Medium Access Control (MAC) layer.

Alternatively, the baseband unit may be implemented by a field programmable gate array (FieldProgrammable Gate Array, FPGA), an application specific integrated circuit (Application Specific Integrated Circuit, ASIC) or a digital signal processor (Digital Signal Processor, DSP); the upper layer protocol unit can be realized by ASIC or general purpose processor such as X86/64, ARM, etc.

Further, the wireless virtual reality system can realize the functions of 3 signal links, including a high-speed data transmission link, a channel detection link and a feedback link; the high-speed data transmission link is used for transmitting high-definition video and high-fidelity audio; the channel detection link is used for transmitting a channel detection signal; the feedback link is used for the helmet to feed back information to the host computer, wherein the feedback information comprises channel quality, operation commands of a user, signals of various sensors and the like.

Further, the bandwidth of the high-speed data transmission link is an integer multiple of the bandwidth of the channel detection link, and is represented by Q; the carrier frequencies used by the high-speed data transmission link and the channel sounding link are the same, and the carrier frequencies are in the millimeter wave frequency band.

Further, the remote radio unit further comprises an interpolator, a switch and two shaping filters; the interpolator is used for repeatedly inserting the value of each data point in the baseband signal into the data stream Q times; one shaping filter accords with the bandwidth of the high-speed data transmission link, and the other shaping filter accords with the bandwidth of the channel detection link; the switch is used for switching the two shaping filters.

Specifically, the remote radio unit is not only responsible for transmitting the high-speed data transmission link signals, but also responsible for transmitting the channel sounding link signals. When the signal of the channel detection link is transmitted, the signal from the baseband unit passes through the interpolator at first, the value of each data point in the baseband signal is repeated Q times and is inserted into the data stream, then the signal enters the analog circuit through the digital-to-analog converter, and then the signal passes through the shaping filter, and the shaping filter is switched through the switch. After the signal comes out of the shaping filter, the up-conversion, power amplification and other circuit modules of the high-speed data transmission link are still used.

Furthermore, the remote radio unit adopts an analog beam forming technology.

Furthermore, the helmet adopts a hybrid analog/digital beam forming technology, and the helmet comprises a first radio frequency channel and a second radio frequency channel; the first radio frequency channel is used for receiving signals of the high-speed data transmission link; the second radio frequency channel is used for receiving signals of the channel detection link.

Further, a high-speed data transmission link of the helmet uses a high-precision analog-to-digital converter, and a channel detection link of the helmet uses a low-precision analog-to-digital converter; wherein the accuracy of the high accuracy analog-to-digital converter is at least 4 bits higher than the accuracy of the low accuracy analog-to-digital converter.

Furthermore, the feedback link adopts a frequency band below 6 GHz; the helmet comprises a signal transmitting module of 1 feedback link, wherein the signal transmitting module comprises 1 transmitting antenna; the host comprises a signal receiving module of 1 feedback link, and the signal receiving module is positioned in any one of 8 remote radio units; the signal receiving module comprises 1 receiving antenna.

Further, the host computer also comprises a high-performance display card for generating and rendering images; the helmet also includes a display screen, headphones, a gyroscope, and an eye tracking sensor. The wireless virtual reality system further comprises a handle, and the handle is connected with the helmet.

Further, the workflow of the wireless virtual reality system includes:

step S1: initializing a wireless virtual reality system; each remote radio unit performs exhaustive search of the beam direction and records the azimuth angle from the remote radio unit to the helmet; in the horizontal direction, only 90 degrees, i.e. 1/4 plane, need to be searched; in the vertical direction, only 90 degrees, namely an upper half space or a lower half space, need to be searched; the helmet performs exhaustive search in the horizontal direction of 360 degrees and the vertical direction of 180 degrees, and records the azimuth angle from the helmet to each remote radio unit;

step S2: the helmet calculates the signal intensity from each remote radio unit to the helmet, and selects the remote radio unit with the best channel quality as the first remote radio unit for high-speed data transmission;

step S3: the helmet sends the information of the selected first remote radio unit to the host computer through a feedback link;

step S4: the wireless virtual reality system is in a normal working state; the host computer utilizes the high-performance display card to complete the generation and rendering of the image, and then sends the high-definition video and the high-fidelity audio to the helmet through the first remote radio unit; the other 7 remote radio units which are not selected by the helmet send channel detection signals to the helmet through wheel flows at preset time intervals;

step S5: the helmet receives high-definition video and high-fidelity audio sent by a host through a first radio frequency channel provided with a high-precision analog-to-digital converter, plays video signals through a display, and plays audio signals through an earphone; meanwhile, the helmet directs the wave beam to each remote radio unit in sequence through a second radio frequency channel provided with a low-precision analog-to-digital converter and receives a channel detection signal;

step S6: the helmet continuously updates the channel quality from the helmet to each remote radio unit according to the channel detection signal; meanwhile, the helmet collects feedback information comprising confirmation information of successful video and audio signal transmission, various operation instructions of a handle, user gesture information provided by a gyroscope, gazing direction of eyes of a user provided by an eyeball tracking sensor and the like, and sends the feedback information to the host through a feedback link;

step S7: if the helmet finds that the signal quality of the high-speed data transmission link is suddenly reduced, judging that an obstacle is encountered, and turning to the step S8; otherwise, turning to step S4;

step S8: the helmet selects a remote radio unit with the best channel quality from the rest 7 remote radio units to be determined as a first remote radio unit, and feeds back information of the newly selected first remote radio unit to the host through a feedback link;

step S9: after receiving feedback from the helmet, the host computer changes the newly selected first remote radio unit to belong to a high-speed data transmission link; the remote radio unit originally used for high-speed data transmission belongs to the channel detection link instead.

The wireless virtual reality system based on distributed antenna that this patent provided has following technical effect:

1) And by adopting a distributed antenna technology, the remote radio units are arranged at the 8 vertexes of the room, and when an obstacle appears between one remote radio unit and the helmet, the remote radio units can be switched to other remote radio units.

2) The remote radio unit adopts an analog beam forming technology, and the helmet adopts a hybrid analog/digital beam forming technology, so that the power consumption and the hardware complexity can be reduced.

3) The high-speed data transmission link uses a high-precision analog-to-digital converter, and the channel detection link uses a low-precision analog-to-digital converter, so that the power consumption of the analog-to-digital converter in the helmet can be reduced.

4) 8 remote radio units share the baseband module and the upper layer protocol module, no matter which remote radio unit the helmet performs data transmission with, the helmet belongs to the same cell logically, so that cell switching is not needed when changing the remote radio units; in addition, the helmet continuously updates the channel quality between the helmet and each remote radio unit and saves the azimuth angle of the beam, so that the beam search is not needed when the signal shielding problem occurs, and the remote radio units can be switched rapidly.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an application environment provided by an embodiment of the present application;

fig. 2 is a schematic diagram of a workflow of a wireless virtual reality system based on a distributed antenna according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.

Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the present application. In the description of the present application, it should be understood that the terms "upper," "lower," "top," "bottom," and the like indicate an orientation or a positional relationship based on that shown in the drawings, and are merely for convenience of description and simplicity of description, and do not indicate or imply that the apparatus or elements in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may include one or more of the feature, either explicitly or implicitly. Moreover, the terms "first," "second," and the like, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or otherwise described herein.

Referring to fig. 1, fig. 1 is a schematic view of an application environment provided in an embodiment of the present application, including a host and a helmet 101, where the host includes 8 remote radio units (Remote Radio Units, RRUs) 102; assuming that the room in which the virtual reality system is placed is a cuboid, 8 remote radio units 102 are installed at 8 vertices of the room, respectively. The 8 remote units 102 are in two different modes of operation: wherein 1 remote radio unit 102 is configured to transmit high definition video and high fidelity audio to helmet 101; the other 7 remote units 102 are used to send channel sounding signals to the helmet 101 in turn.

In this embodiment of the present application, the host further includes 1 baseband unit and 1 upper layer protocol unit. The baseband unit is responsible for baseband signal processing, and the upper protocol unit is responsible for processing all communication protocols above the Medium Access Control (MAC) layer. The 8 remote units 102 share 1 baseband unit and 1 upper layer protocol unit.

The embodiment of the application adopts millimeter wave communication technology to transmit high-definition video and high-fidelity audio. The millimeter wave band has large bandwidth, so that the data transmission speed can be improved. One common millimeter wave system deployment method in the prior art is that one macro station is provided with a plurality of millimeter wave small stations. Under this structure, each millimeter wave small station is an independent entity, and each of them transmits its own wireless signal. At the overlapping position of the coverage areas of the two millimeter wave small stations, the macro station is responsible for coordinating the signals of the two millimeter wave small stations so as to reduce the mutual interference as much as possible. If a user moves from the coverage area of one mmwave cell to the coverage area of another cell, it is also necessary to transfer the user's registration information in the wireless network from the last mmwave cell to the next mmwave cell using a cell handoff procedure.

In the wireless virtual reality system based on the distributed antenna, 8 remote radio units 102 share 1 baseband unit and 1 upper layer protocol unit. The advantage of doing so is: on the one hand, the helmet 101 logically belongs to the same cell no matter which remote radio unit 102 the helmet 101 is in data transmission with, so that no cell switch is required. If an obstacle appears between the currently used remote unit 102 and the helmet 101, the remote unit 102 can be immediately switched to another remote unit 102 for data transmission. In the structure of "macro station with multiple mmwave stations", only the cell switch is completed, and the new remote radio unit 102 can be used for data transmission. This can lead to transmission interruptions that occur for a period of time. For example, in an LTE system, the time required for cell handover is approximately 50 milliseconds. In a virtual reality system, the user may experience a dizziness if the delay exceeds 20 milliseconds. On the other hand, in the structure of "macro station with a plurality of millimeter wave small stations", each millimeter wave small station requires 1 baseband unit and 1 upper layer protocol unit. A total of 8 mmwave substations require 8 baseband units and 8 upper layer protocol units. In the embodiment of the application, only 1 baseband unit and 1 upper layer protocol unit are needed, so that the complexity of hardware is effectively reduced. In addition, the distributed antenna system does not need to be specially provided with a device similar to a macro station to coordinate the operation of a plurality of remote radio units 102, thereby further simplifying the hardware structure.

Alternatively, the baseband unit may be implemented by FPGA, ASIC or DSP; the upper layer protocol unit can be realized by ASIC or general purpose processor such as X86/64, ARM, etc.

In millimeter wave communication, it is necessary to compensate for path loss using a large-scale antenna technology. If each antenna is equipped with a separate radio frequency channel (RF chain), the hardware cost is very high and the power consumption is huge. In the embodiment of the present application, the remote radio unit 102 uses an analog beamforming technique (Analog Beamforming), that is, all antennas installed on one remote radio unit share 1 rf channel. Thus, cost and power consumption can be reduced.

In the embodiment of the application, the wireless virtual reality system realizes 3 data links, including a high-speed data transmission link, a channel detection link and a feedback link; the high-speed data transmission link is used for the host to send high-definition video and high-fidelity audio to the helmet 101; the channel detection link is used for the host to send a channel detection signal to the helmet 101; the feedback link is used by the helmet 101 to feed back information to the host, including channel quality, user operating commands, and signals from the various sensors, etc.

During data transmission, once an obstacle is encountered between the remote unit 102 currently transmitting data and the helmet 101, the remote unit 102 is switched to other remote units. In order to shorten the time required as much as possible, it is necessary to know in advance which remote radio unit 102 the beam should be aimed at, and the corresponding azimuth of the beam. This means that data transmission and scanning of the alternative beams are performed simultaneously. In the embodiment of the application, the channel detection link is used for scanning the alternative beam. While 1 remote radio unit 102 performs high-speed data transmission with the helmet 101, the remaining 7 remote radio units 102 alternately transmit channel sounding signals to the helmet 101.

In the embodiment of the application, the bandwidth of the high-speed data transmission link is an integer multiple of the bandwidth of the channel detection link, and is represented by Q; the carrier frequency of the channel detection link is the same as that of the high-speed data transmission link, and the carrier frequency is in the millimeter wave frequency band.

The channel sounding link does not require as much bandwidth as the high speed data transmission link. Typically, the channel sounding link requires only a maximum of 10MHz bandwidth, and may be less practical. While the bandwidth of high-speed data transmission links is often several hundred MHz, or even up to GHz. The bandwidth of the high-speed data transmission link is about 10-100 times that of the channel sounding link. This means that the remote radio unit 102 needs to support the transmission of both bandwidth signals simultaneously. A simple approach is to design two radio frequency channels to support the high speed data transmission link and the channel sounding link, respectively, but this increases hardware complexity.

Considering that each remote radio unit 102 will only transmit one bandwidth signal at a time, the embodiments of the present application use the hardware devices of the high-speed data transmission link to transmit the small bandwidth channel sounding link signal.

In this embodiment, the remote radio unit includes an interpolator, a switch, and two shaping filters (shaping filters); the interpolator is used for repeatedly inserting the value of each data point in the baseband signal into the data stream Q times; one shaping filter accords with the bandwidth of the high-speed data transmission link, and the other shaping filter accords with the bandwidth of the channel detection link; the switch is used for switching the two shaping filters.

Specifically, the bandwidth of the high-speed data transmission link is set to be an integral multiple of the bandwidth of the channel sounding link, and the bandwidth is denoted by Q. Typical values of Q are 10 times, 20 times, 50 times, or 100 times. When transmitting the signal of the channel detection link, the baseband signal from the baseband unit passes through the interpolator first, the value of each data point in the baseband signal is repeated Q times and inserted into the data stream, and then enters the analog circuit through the digital-to-analog converter. In analog circuits, the shaping filter determines the bandwidth of the transmitted signal. Thus, in the present embodiment, the remote radio unit 102 includes two shaping filters, one for the high-speed data transmission link and the other for the channel sounding link. The two shaping filters are switched by a switch (switch). After the signal comes out of the shaping filter, the up-conversion, power amplification and other circuit modules of the high-speed data transmission link are still used.

Analog beamforming techniques, while having low hardware complexity, have the biggest disadvantage of being able to direct a beam in only one direction at a time. In embodiments of the present application, helmet 101 employs Hybrid Analog/digital beamforming technology (Hybrid Analog/Digital Beamforming), helmet 101 comprising a first radio frequency channel and a second radio frequency channel; the first radio frequency channel belongs to a high-speed data transmission link and is used for carrying out high-speed data transmission with the host. The second rf channel belongs to a channel sounding link, and directs the beam to each remote radio unit 102 in sequence, and detects the link quality of these channels by receiving the channel sounding signal, so that the remote radio units 102 used can be switched in time when an obstacle occurs. In this manner, helmet 101 may simultaneously complete the reception of both the high-speed data transmission link and the channel sounding link signals.

The millimeter wave band, due to the large bandwidth, results in large power consumption of the analog-to-digital converter (ADC), which reduces the usable time of the battery of the helmet 101. In order to solve the above technical problem, in the embodiment of the present application, the high-speed data transmission link of the helmet 101 uses a high-precision analog-to-digital converter, and the channel detection link of the helmet 101 uses a low-precision analog-to-digital converter. Wherein the accuracy of the high accuracy analog-to-digital converter is at least 4 bits higher than the accuracy of the low accuracy analog-to-digital converter. This has the advantage that the channel-sounding signal is only used to compare the quality of the channel from the helmet 101 to the respective remote units 102, so that a particularly high accuracy is not required. For example, the power consumption of an 8-bit precision analog-to-digital converter is 1/16 of that of a 12-bit precision analog-to-digital converter of the same speed. The channel sounding link may reduce power consumption using a low precision analog to digital converter.

Alternatively, typical values for the accuracy of a high-accuracy analog-to-digital converter are 10 bits, 12 bits.

Alternatively, typical values for the low-precision analog-to-digital converter precision are 4 bits, 6 bits, 8 bits.

In the embodiment of the application, the feedback link adopts a frequency band below 6 GHz; helmet 101 comprises a signal transmission module of 1 feedback link, the signal transmission module comprising 1 transmission antenna; the host comprises a signal receiving module of 1 feedback link, and the signal receiving module is positioned in any one radio remote unit 102 in 8 radio remote units 102; the signal receiving module comprises 1 receiving antenna.

Optionally, the feedback link employs an unlicensed frequency band of 2.4GHz or 5 GHz.

Firstly, the data volume of the feedback link is smaller, a large bandwidth is not needed, and in general, only a bandwidth of 20MHz is needed at most, which is practically possible to be less, the bandwidth of the feedback link is far smaller than that of the high-speed data transmission link, and the feedback delay can be reduced when the feedback link and the high-speed data transmission link are positioned in non-overlapping frequency bands; secondly, the feedback link adopts a frequency band below 6GHz, which is more robust to obstacles than a high-speed data transmission link and a channel detection link, so that the helmet 101 is beneficial to feeding back information of encountering obstacles to a host computer through the feedback link; thirdly, the feedback link does not need to be provided with an antenna array, so that a hardware circuit can be simplified; fourth, because the wireless signals of the frequency band below 6GHz are more robust to the obstacle, the host computer does not need to install a signal receiving module in each remote radio unit 102, and only needs to select one remote radio unit 102 from 8 remote radio units 102 to install, so that the hardware circuit can be further simplified. Alternatively, the signal receiving module may be installed in the remote radio unit 102 that is relatively open in the surroundings.

In the embodiment of the application, the host computer further comprises a high-performance display card for generating and rendering the image. Helmet 101 also includes devices such as a display screen, headphones, gyroscopes, eye tracking sensors, and the like. Helmet 101 receives the high definition video and high fidelity audio sent by the host, and transmits video information to the display screen to play video and audio information to the earphone to play audio after demodulation is successful. The gyroscope is used for acquiring gesture information of a user. The eye tracking sensor is used for capturing the gazing direction of eyes of a user. The wireless virtual reality system further includes a handle connected to the helmet 101, and a user can send various commands through the handle and feed back the commands to the host through the helmet 101.

In summary, the wireless virtual reality system provided in this embodiment of the present application has 8 remote radio units 102, and when an obstacle appears between one of the remote radio units 102 and the helmet 101, the remote radio units 102 can be quickly switched to other remote radio units 102, so that the signal shielding problem can be effectively solved, and high-speed data transmission between the host and the helmet 101 is ensured. Meanwhile, the rest remote radio units 102 send channel detection signals, so that the channel quality between the helmet 101 and each remote radio unit 102 is continuously updated, and the time required for switching the remote radio units 102 is reduced.

Referring to fig. 2, fig. 2 is a schematic diagram of a workflow of a wireless virtual reality system based on a distributed antenna according to an embodiment of the present application, where the workflow includes:

step S1: initializing a wireless virtual reality system; each remote radio unit 102 performs an exhaustive search of beam directions, and records azimuth angles from each remote radio unit 102 to the helmet 101; in the horizontal direction, only 90 degrees, i.e. 1/4 plane, need to be searched; in the vertical direction, only 90 degrees, namely an upper half space or a lower half space, need to be searched; helmet 101 makes an exhaustive search in the horizontal direction 360 degrees and in the vertical direction 180 degrees, and records the azimuth angle of helmet 101 to each remote radio unit 102;

step S2: helmet 101 calculates the signal strength of each remote unit 102 to helmet 101 and picks out the remote unit 102 with the best channel quality as the first remote unit for high-speed data transmission;

step S3: helmet 101 sends the information of the selected first remote radio unit to the host computer through a feedback link;

step S4: the wireless virtual reality system is in a normal working state; the host computer utilizes the high-performance display card to complete the generation and rendering of the image, and then sends the high-definition video and the high-fidelity audio to the helmet 101 through the first remote radio unit; the remaining 7 remote units 102 not selected by the helmet 101 transmit channel sounding signals to the helmet 101 at preset time intervals;

step S5: helmet 101 receives the high definition video and high fidelity audio from the host computer via a first rf channel equipped with a high precision analog-to-digital converter, and plays the video signal via the display and the audio signal via the earphone; while helmet 101 directs the beam to each remote radio unit 102 in turn and receives the channel detect signal via a second rf channel equipped with a low-precision analog-to-digital converter;

step S6: helmet 101 continuously updates the channel quality of helmet 101 to each remote radio unit 102 according to the channel detection signal; meanwhile, the helmet 101 collects feedback information including confirmation information of successful video and audio signal transmission, various operation instructions of a handle, user gesture information provided by a gyroscope, gazing direction of eyes of a user provided by an eyeball tracking sensor and the like, and sends the feedback information to a host through a feedback link;

step S7: if the helmet 101 finds that the signal quality of the high-speed data transmission link is drastically reduced, it is determined that an obstacle is encountered, and the process goes to step S8; otherwise, turning to step S4;

step S8: the helmet 101 selects a remote radio unit 102 with the best channel quality from the rest 7 remote radio units 102 to be determined as a first remote radio unit, and feeds back the information of the newly selected first remote radio unit to the host through a feedback link;

step S9: after receiving feedback from the helmet 101, the host computer changes the newly selected first remote radio unit to belong to a high-speed data transmission link; the remote radio unit originally used for high-speed data transmission belongs to the channel detection link instead.

It should be noted that: the foregoing sequence of the embodiments of the present application is only for describing, and does not represent the advantages and disadvantages of the embodiments. And the foregoing description has been directed to specific embodiments of this specification. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

The foregoing description of the preferred embodiments of the present application is not intended to be limiting, but rather is intended to cover any and all modifications, equivalents, alternatives, and improvements within the spirit and principles of the present application.

Claims

1. A wireless virtual reality system based on a distributed antenna is characterized by comprising a host and a helmet;

the host comprises 8 remote radio units which are respectively arranged at 8 vertexes of a room; the remote radio unit 1 is used for sending high-definition video and high-fidelity audio to the helmet; simultaneously, 7 other remote radio unit wheels transmit channel detection signals to the helmet;

the wireless virtual reality system can realize the functions of 3 signal links, including a high-speed data transmission link, a channel detection link and a feedback link; wherein the bandwidth of the high-speed data transmission link is an integer multiple of the bandwidth of the channel detection link, and the bandwidth is represented by Q;

the remote radio unit further comprises an interpolator, a switch and two shaping filters; the interpolator is used for repeatedly inserting the value of each data point in the baseband signal into the data stream Q times; one of the shaping filters conforms to the bandwidth of the high-speed data transmission link, and the other shaping filter conforms to the bandwidth of the channel detection link; the switch is used for switching the two shaping filters.

2. The wireless virtual reality system of claim 1, wherein the host further comprises 1 baseband unit and 1 upper layer protocol unit;

the 8 remote radio units share the baseband unit and the upper layer protocol unit.

3. The wireless virtual reality system of claim 1, wherein the wireless virtual reality system is configured to,

the high-speed data transmission link is used for transmitting high-definition video and high-fidelity audio;

the channel detection link is used for sending a channel detection signal;

the feedback link is used for the helmet to feed back information to the host computer, wherein the feedback information comprises channel quality, operation commands of a user, signals of various sensors and the like.

4. The wireless virtual reality system of claim 3,

the carrier frequencies of the high-speed data transmission link and the channel detection link are the same, and the carrier frequency is located in the millimeter wave frequency band.

5. The wireless virtual reality system of claim 1, wherein the helmet employs hybrid analog/digital beamforming techniques; the helmet comprises a first radio frequency channel and a second radio frequency channel, wherein the first radio frequency channel is used for receiving signals of the high-speed data transmission link; the second radio frequency channel is used for receiving the signal of the channel detection link;

the remote radio unit adopts an analog beam forming technology.

6. The wireless virtual reality system of claim 5, wherein a high-speed data transmission link of the helmet uses a high-precision analog-to-digital converter and a channel detection link of the helmet uses a low-precision analog-to-digital converter;

wherein the precision of the high precision analog-to-digital converter is at least 4 bits higher than the precision of the low precision analog-to-digital converter.

7. The wireless virtual reality system of claim 3, wherein the feedback link employs a frequency band below 6 GHz;

the helmet comprises a signal transmitting module with 1 feedback link, wherein the signal transmitting module comprises 1 transmitting antenna;

the host comprises a signal receiving module of 1 feedback link, and the signal receiving module is positioned in any one of the 8 remote radio units; the signal receiving module comprises 1 receiving antenna.

8. The wireless virtual reality system of claim 1, further comprising a handle connected to the helmet;

the host computer also comprises a high-performance display card for generating and rendering images;

the helmet further comprises a display screen, an earphone, a gyroscope and an eyeball tracking sensor.

9. The wireless virtual reality system of claim 1, wherein the workflow of the wireless virtual reality system comprises:

step S1: initializing the wireless virtual reality system; each remote radio unit performs exhaustive search of the beam direction and records the azimuth angle from the remote radio unit to the helmet; in the horizontal direction, only 90 degrees, i.e. 1/4 plane, need to be searched; in the vertical direction, only 90 degrees, namely an upper half space or a lower half space, need to be searched; the helmet performs exhaustive search in 360 degrees in the horizontal direction and 180 degrees in the vertical direction, and records azimuth angles from the helmet to each remote radio unit;

step S4: the wireless virtual reality system is in a normal working state; the host computer utilizes a high-performance display card to complete the generation and rendering of images, and then sends the high-definition video and the high-fidelity audio to the helmet through the first remote radio unit; the rest 7 remote radio units which are not selected by the helmet send the channel detection signals to the helmet through a preset time interval wheel;

step S5: the helmet receives high-definition video and high-fidelity audio sent by the host through a first radio frequency channel provided with a high-precision analog-to-digital converter, plays video signals through a display, and plays audio signals through an earphone; simultaneously, the helmet directs wave beams to each remote radio unit in sequence through a second radio frequency channel provided with a low-precision analog-to-digital converter and receives channel detection signals;

step S7: if the helmet finds that the signal quality of the high-speed data transmission link is suddenly reduced, judging that an obstacle is encountered, and turning to step S8; otherwise, go to step S4;

step S8: the helmet selects a remote radio unit with the best channel quality from the rest 7 remote radio units to be determined as the first remote radio unit, and feeds back the information of the newly selected first remote radio unit to the host through the feedback link;