Channel reservation method for video service quality assurance

Abstract

The invention discloses a channel reservation method for video service quality assurance. The method comprises the following steps: firstly, performing static queue mapping on a video frame by a V-STA; then, the V-STA sends a channel reservation request frame; next, replying a channel reservation response frame by the VR-STA; receiving a channel reservation response frame; and finally, in the SP stage, all stations need to end the current data transmission, and the channel is ensured to be in an idle state when the SP starts. According to the invention, different video frame types can be reasonably mapped to different priorities according to a cross-layer queue mapping mechanism, and channel reservation is flexibly executed, so that the QoS requirements of low-delay and high-reliability video streaming services are ensured.

Description

Technical Field

[0001] The present invention belongs to the field of network technology, and particularly relates to a channel reservation method for video service quality guarantee. Background Art

[0002] With the rapid development of information technology, wireless local area networks (WLANs), typified by Wi-Fi networks, have become an important part of modern communication infrastructure, profoundly affecting people's daily lives and work styles. Due to the characteristics of high transmission rate, low cost, and open use of WLANs, they have received extensive attention from the industrial and academic communities. Since the Institute of Electrical and Electronics Engineers (IEEE) established the 802.11 committee in 1990, the Wi-Fi protocol has gradually developed into an important standard in the field of wireless communication. In 1997, the IEEE released the first WLAN protocol, namely the IEEE 802.11 standard, marking the official start of wireless local area network technology. With the continuous development of wireless communication technology and the increasing demands, the IEEE 802.11 protocol family has undergone several important technological evolutions and expansions, such as IEEE 802.11a / b / g / n / ac / ax, and it is expected to release the 802.11be standard in 2025 and the 802.11bn standard in 2028. Each generation of protocols has been optimized according to new application scenarios and changing requirements, achieving significant improvements in transmission rate, spectrum utilization, anti-interference ability, and multi-user support to meet more complex future application requirements.

[0003] In WLAN, the channel access method is mainly based on the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism. By listening to the status of the air interface and using a random backoff algorithm, collisions are reduced and efficiency is improved. The early IEEE 802.11 standard used the Distributed Coordination Function (DCF) as the basic channel access protocol, which is suitable for general data transmission scenarios. With the rise of real-time services such as voice and video, to better support Quality of Service (QoS), IEEE 802.11 introduced the Enhanced Distributed Channel Access (EDCA) mechanism. By differentiating different priority queues, timely transmission of important traffic is guaranteed. However, in practical applications, limited spectrum resources, high interference, and the situation of multiple users accessing simultaneously make it a key challenge in the wireless local area network environment to utilize the channel more efficiently, reduce collisions, and improve the overall throughput.

[0004] With the rapid development of mobile communication technology and the Internet, the proportion of video traffic in the total network traffic has been continuously increasing and has become one of the core driving forces for network traffic growth. From high-definition video on demand to ultra-high-definition video live streaming, as well as new forms of video applications such as virtual reality and augmented reality, users' demand for high-quality video content shows an exponential growth trend. These applications not only pose a huge challenge to network bandwidth but also put forward strict requirements for transmission delay, jitter, and reliability. Against this background, application scenarios such as real-time interaction and online live streaming further raise the expectations for network performance. On the one hand, in the case of limited or unevenly distributed bandwidth resources, these scenarios need to be able to efficiently and stably transmit large-scale video traffic to avoid a decline in service quality caused by resource bottlenecks. On the other hand, the network must be able to achieve low-latency and high-reliable transmission performance in a complex and dynamic environment to ensure a smooth experience for users when watching videos or participating in real-time interactions.

[0005] The EDCA mechanism in IEEE 802.11 is a QoS guarantee mechanism proposed in the IEEE 802.11e standard, aiming to solve the priority transmission problem of different types of services in WLAN. Through the EDCA mechanism, the network can perform differential channel access control on different types of service traffic according to the priority of the data stream, thereby improving the QoS for delay-sensitive services such as video and voice.

[0006] The EDCA mechanism realizes QoS guarantee by dividing data streams into four different access categories (ACs), as Figure 1 shown. Each AC is assigned a different priority according to the characteristics of the service, and the specific classification is as follows:

[0007] 1) Background type (AC_Background, AC_BK): Background traffic, with the lowest priority, usually used for file downloads or non-real-time data transmission.

[0008] 2) Best-Effort type (AC_Best-Effort, AC_BE): Best-Effort traffic, ordinary services without special priorities, suitable for general data transmission.

[0009] 3) Video type (AC_Video, AC_VI): Video traffic that is more sensitive to delay and jitter, with a higher priority than AC_BK and AC_BE.

[0010] 4) Voice type (AC_Voice, AC_VO): Voice traffic with the highest requirements for delay and jitter, with the highest priority.

[0011] The EDCA mechanism realizes priority scheduling for different service flows by setting different arbitration inter-frame space (AIFS), contention window (CW), transmission opportunity (TXOP) limit and other parameters for different service categories, so as to meet their QoS requirements. Next, the roles of these parameters in the EDCA mechanism will be introduced separately.

[0012] (1) AIFS

[0013] In the EDCA mechanism, AIFS defines the time slots that each AC needs to wait when detecting that the channel is idle. Service categories with higher priorities have shorter AIFS values, can detect the idle state of the channel earlier, and initiate transmission requests quickly, reducing the channel waiting time.

[0014] As Figure 2 shown, different inter-frame spaces (IFS) are designed based on the same basic time architecture. All IFS time periods are extended based on the short inter-frame space (SIFS) as the reference time slice. Specifically, AIFS consists of SIFS and several time slots (Slot), and AIFS for different priority services has different numbers of time slots. Its calculation formula is as follows:

[0015] t AIFS = t SIFS + nt slot

[0016] Where n represents the number of time slots related to the service priority. The n values for different ACs are defined in the IEEE 802.11e standard, as shown in Table 1. Services with higher priority use smaller n values, enabling them to enter the channel competition state faster, while services with lower priority need to wait for a longer AIFS time, resulting in their relative lag in channel competition.

[0017] Table 1 AIFSn Configuration Table for Four ACs of STA in EDCA

[0018] AC N AC_VO 2 AC_VI 2 AC_BE 3 AC_BK 7

[0019] Through such a design, the AIFS parameter provides a basis for QoS guarantee in the EDCA mechanism, ensuring that high-priority services can obtain channel resources preferentially, thus meeting their strict requirements for delay and jitter.

[0020] (2) CW

[0021] CW is one of the key parameters for controlling channel competition in the EDCA mechanism. When a STA attempts to access the channel, after detecting that the channel is idle, it needs to select a random backoff time, which is randomly selected within the range specified by CW. CW is determined by the two parameters CW min and CW max When a STA first enters the channel competition, the backoff value will be randomly selected within the range of [0, CW min - 1]. If the competition fails, that is, the channel is occupied before the backoff time ends, the CW value will increase exponentially until it reaches CW max This mechanism ensures that high-priority services use smaller CW min and CW max , thus shortening the backoff time and enabling them to obtain the channel preferentially, guaranteeing the QoS of high-priority services.

[0022] As shown in Table 2, the CW parameter configurations for different ACs are different. Among them, AC_VO and AC_VI are set with smaller CW min and CW max , ensuring that high-priority services can access the channel faster, thereby improving their transmission performance; while AC_BE and AC_BK have a larger CW range and are relatively lagging in channel competition to avoid interfering with high-priority services.

[0023] Table 2 CW Parameter Configuration Table for Four ACs in EDCA

[0024] AC <![CDATA[CW min > <![CDATA[CW max > AC_VO 3 7 AC_VI 7 15 AC_BE 15 1023 AC_BK 15 1023

[0025] By reasonably configuring the CW parameters, EDCA can effectively guarantee the QoS of different services, enabling high-priority services to have a higher success probability when accessing the channel, and significantly improving the transmission stability and response speed of real-time services.

[0026] (3)TXOP

[0027] TXOP is one of the key parameters in the EDCA mechanism, mainly used to control the maximum data transmission duration after each successful channel acquisition. The TXOP limit parameter allows each AC to occupy the channel for a fixed period of time for transmission after successfully obtaining the channel, without having to re-compete for each packet sent.

[0028] Table 3 TXOP limit configuration table for four ACs in EDCA

[0029]

[0030] As shown in Table 3, the EDCA mechanism assigns different TXOP limit durations according to the priorities of different ACs. Among them, AC_VO and AC_VI, as access categories sensitive to delay, are set with longer TXOP values, allowing them to transmit more packets during a single channel access. This can not only effectively reduce the average waiting time and contention overhead of these services, but also significantly improve their QoS. On the contrary, the TXOP values of AC_BE and AC_BK are set to 0, indicating that they can only re-enter the channel contention after sending a single packet, thus releasing more resources to high-priority services and ensuring the delay and jitter requirements of high-priority services.

[0031] The quality of service of video services has its own characteristics. For example, the packets generated by video streams at the application layer based on video coding often have the characteristics of layering or frame classification. For example, a video stream can be divided into different frame types such as I-frames, B-frames, and P-frames, and the transmission performance of different types of frames contributes differently or has different impacts on the overall quality of service of the video. However, in the existing technology, WLAN only relies on the MAC layer mechanism to try to guarantee the QoS of video services, often ignoring the frame types and characteristics of the application layer, resulting in low resource allocation and management efficiency and being difficult to meet the quality of service requirements of video services. Summary of the Invention

[0032] To overcome the deficiencies of the prior art, the present invention provides a channel reservation method for video service quality assurance. First, the V-STA performs static queue mapping on video frames; then the V-STA sends a channel reservation request frame; next, the VR-STA replies with a channel reservation response frame; then the channel reservation response frame is received; finally, in the SP phase, all stations need to end the current data transmission to ensure that the channel is idle at the start of the SP. The present invention can reasonably map different video frame types to different priorities according to the cross-layer queue mapping mechanism and flexibly execute channel reservation, ensuring the QoS requirements of low-latency and highly reliable video stream services.

[0033] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0034] Step 1: The V-STA performs static queue mapping on video frames;

[0035] The MAC layer of the V-STA maps different video frames to different priority queues according to their frame types;

[0036] According to the coding standard used, the video stream is encoded into multiple types of frames, denoted as type 1, type 2,..., type N. Each type of frame has a different impact on the video transmission quality; in the MAC layer of the V-STA, there are multiple queues; the MAC layer uniquely maps each type of video frame to a priority queue; different types of video frames are allowed to be mapped to the same priority queue;

[0037] Step 2: The V-STA sends a channel reservation request frame;

[0038] After completing the queue mapping, the V-STA sends a channel reservation request frame to the VR-STA to reserve channel resources and ensure the transmission requirements of key frames;

[0039] The channel reservation request frame contains the following information:

[0040] 1) Video frame type: used to indicate the type of the video frame;

[0041] 2) SP start time: aligned with the generation time of the subsequent key frames of the V-STA;

[0042] 3) SP duration: reserve sufficient time for transmitting video frames;

[0043] 4) SP arrival period: combined with the GOP characteristics, plan the SP arrival period of the V-STA;

[0044] 5) Silent interval duration: set to ensure the transmission of key frames during the silent period;

[0045] Step 3: The VR-STA replies with a channel reservation response frame;

[0046] After receiving the channel reservation request frame from the V-STA, the VR-STA replies with an acknowledgment frame; the acknowledgment frame has two implementation methods;

[0047] In implementation method 1, the acknowledgment result field is used to indicate whether to agree to the channel reservation request of the V-STA; if agreed, all subsequent fields must be exactly the same as the information in the channel reservation request frame; if not agreed, all subsequent fields are ineffective;

[0048] In implementation method 2, the channel reservation acknowledgment frame replied by the VR-STA can carry the channel reservation information of one or more V-STAs. The STA identifier in each reservation information of the VR-STA is used to indicate the V-STA, and a special STA identifier value can be introduced to represent all STAs; all the remaining fields are exactly the same as the information in the channel reservation request frame; if the VR-STA does not agree to the channel reservation request of a certain V-STA, the reservation information of that V-STA is not included in the acknowledgment frame;

[0049] Step 4: Receive the channel reservation acknowledgment frame;

[0050] After the V-STA receives the channel reservation acknowledgment frame from the VR-STA, if the channel reservation acknowledgment frame agrees to the channel reservation request of the V-STA, the V-STA records the SP information of the channel reservation and plans to communicate with the VR-STA in the SP;

[0051] After the NV-STA receives the channel reservation acknowledgment frame from the VR-STA, it records the SP information of the channel reservation;

[0052] Step 5: SP phase;

[0053] Before the reserved SP starts, all stations need to end the current data transmission to ensure that the channel is idle at the start of the SP.

[0054] The NV-STA remains silent from the start time of the SP, and the silent time length is the silent duration indicated by the silent interval to avoid interfering with the reserved transmissions of the V-STA and the VR-STA;

[0055] The V-STA preferentially transmits the reserved frame type from the start of the SP to ensure the timely transmission of key frames and reduce the impact of delay on video quality; if the reserved frame type is sent completely, other frame types are sent.

[0056] A computer program that causes a computer to execute the above channel reservation method.

[0057] An electronic device, comprising: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the electronic device executes the above-mentioned channel reservation method.

[0058] A computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the above-mentioned channel reservation method is implemented.

[0059] A chip, comprising: a processor, configured to call and run a computer program from a memory, so that a device installed with the chip executes the above-mentioned channel reservation method.

[0060] A computer program product, the computer program product includes a computer storage medium, the computer storage medium stores a computer program, the computer program includes instructions that can be executed by at least one processor, and when the instructions are executed by the at least one processor, the above-mentioned channel reservation method is implemented.

[0061] The beneficial effects of the present invention are as follows:

[0062] The present invention can reasonably map different video frame types to different priorities according to the cross-layer queue mapping mechanism, and flexibly execute channel reservation, ensuring the QoS requirements of low-latency and high-reliability video stream services. Description of the Drawings

[0063] Figure 1 Are the four queues of the EDCA mechanism;

[0064] Figure 2 Is a schematic diagram of AIFS;

[0065] Figure 3 Is a static queue allocation diagram;

[0066] Figure 4 Are the information that needs to be carried in the channel reservation request frame;

[0067] Figure 5 Is a diagram of the new fields of the channel reservation response frame, (a) Implementation method 1 of the channel reservation response frame, (b) Implementation method 2 of the channel reservation response frame;

[0068] Figure 6 Is a flowchart of the channel reservation scheme. Detailed Embodiments

[0069] The present invention will be further described below with reference to the drawings and embodiments.

[0070] The "station" in the present invention includes both APs and non-AP STAs. The sending end refers to the station with video traffic transmission requirements (Video Station, V-STA), and the receiving end refers to the station that receives and processes video traffic (Video Receiving Station, VR-STA). Other nodes do not participate in the generation or reception of video traffic (Non-Video Station, NV-STA).

[0071] The embodiment guarantees the transmission of video key frames and thus the QoS of the video by means of static cross-layer queue mapping and static setting of the silent interval duration in the WLAN.

[0072] Step 1: The V-STA performs static queue mapping on video frames.

[0073] The MAC layer of the V-STA maps different video frames to different priority queues according to their frame types. Specifically, according to the encoding standard used, a video stream is usually encoded into multiple types of frames (denoted as type 1, type 2,..., type N), and the impact of each type of frame on the video transmission quality is different. In the MAC layer of the V-STA, there are often multiple queues (such as queue 1, queue 2,..., queue M). At this time, the MAC layer uniquely maps each type of video frame to a priority queue. It should be noted that different types of video frames are allowed to be mapped to the same priority queue.

[0074] For example, if a video stream only contains two types of frames, i.e., I frames and B frames, I frames usually carry the core information of the video and have a higher transmission priority. While B frames (bi-directionally predicted frames) belong to the frame type for enhancing video performance and are relatively less important for the overall video quality. Assume that the MAC layer of the V-STA has four queues: AC_VO, AC_VI, AC_BE, AC_BK, then the I frames can be mapped to the AC_VO queue, and the B frames can be mapped to the AC_VI queue, as Figure 3 shown.

[0075] Step 2: The V-STA sends a channel reservation request frame;

[0076] After completing the queue mapping, the V-STA needs to send a channel reservation request frame to the VR-STA to reserve channel resources and guarantee the transmission requirements of key frames.

[0077] The channel reservation request frame contains the following information:

[0078] 1) Video frame type: used to indicate the type of video frame, for example, indicating one or more of I frames, B frames, P frames, etc.

[0079] 2) SP start time: precisely aligned with the generation time of the subsequent key frames of the V-STA.

[0080] 3) Duration of SP: Reserve sufficient time for transmitting video frames.

[0081] 4) Arrival period of SP: Combine the GOP characteristics to plan the arrival period of SP for V-STA.

[0082] 5) Duration of silent interval: Ensure the transmission of key frames during the silent period.

[0083] Step 3: VR-STA replies with a channel reservation response frame;

[0084] After receiving the channel reservation request frame from V-STA, VR-STA replies with a response frame. The response frame has two implementation methods. The first implementation method is as shown in Figure 5 (a). The response result field is used to indicate whether to agree to the channel reservation request of V-STA. For example, a value of 0 represents agreement, and a value of 1 represents disagreement. If it agrees, all subsequent fields must be exactly the same as the information in the channel reservation request frame. If it disagrees, all subsequent fields are ineffective.

[0085] The second implementation method is as shown in Figure 5 (b). The channel reservation response frame replied by VR-STA can carry the channel reservation information of one or more V-STAs. The STA identifier in each reservation information of VR-STA is used to indicate V-STA, and a special STA identifier value can be introduced to represent all STAs. All the remaining fields must be exactly the same as the information in the channel reservation request frame. If VR-STA does not agree to the channel reservation request of a certain V-STA, it only needs not to include the reservation information of that V-STA in the response frame.

[0086] Step 4: Receive the channel reservation response frame;

[0087] After receiving the channel reservation response frame from VR-STA, if the channel reservation response frame agrees to the channel reservation request of the V-STA, the V-STA records the SP information of the channel reservation and plans to communicate with VR-STA during the SP.

[0088] After receiving the channel reservation response frame from VR-STA, NV-STA records the SP information of the channel reservation.

[0089] Step 5: SP phase;

[0090] As shown in Figure 6 , before the reserved SP starts, all stations need to end the current data transmission to ensure that the channel is idle at the start of the SP.

[0091] NV-STA remains silent starting from the start time of SP, and the silent duration is the silent period indicated by the silent interval, so as to avoid interfering with the scheduled transmissions of V-STA and VR-STA.

[0092] When starting from SP, V-STA must preferentially transmit the scheduled frame type to ensure the timely transmission of key frames and reduce the impact of latency on video quality. If the scheduled frame type has been transmitted, other frame types can be transmitted.

Claims

1. A channel reservation method for ensuring video service quality, characterized in that: The steps include: Step 1: V-STA performs static queue mapping on video frames; The MAC layer of V-STA maps different video frames to different priority queues according to their frame types; According to the coding standard used, the video stream is encoded into multiple types of frames, denoted as type 1, type 2, ..., type N. Each type of frame has a different degree of influence on the quality of video transmission. In the MAC layer of V-STA, there are multiple queues. The MAC layer uniquely maps each type of video frame to a priority queue. Different types of video frames are allowed to be mapped to the same priority queue; Step 2: V-STA sends a channel reservation request frame; After completing the queue mapping, V-STA sends a channel reservation request frame to VR-STA to reserve channel resources to ensure the transmission requirements of key frames; The channel reservation request frame contains the following information: 1) Video frame type: used to indicate the type of video frame; 2) SP start time: aligned with the generation time of subsequent key frames of V-STA; 3) SP duration: reserve enough time for transmitting video frames; 4) SP arrival period: Plan the SP arrival period of V-STA in combination with GOP characteristics; 5) Silence interval duration: Set the silence period to ensure the transmission of key frames; Step 3: VR-STA replies with a channel reservation response frame; After receiving the channel reservation request frame from V-STA, VR-STA replies with a response frame. The response frame includes two implementation methods. In implementation mode 1, the response result field is used to indicate whether the channel reservation request of the V-STA is approved; If agreed, all subsequent fields must be completely consistent with the information in the channel reservation request frame; If you disagree, all subsequent fields will be invalid. In implementation mode 2, the channel reservation response frame replied by the VR-STA can carry the channel reservation information of one or more V-STAs. The STA identifier in each reservation information of the VR-STA is used to indicate the V-STA, wherein a special STA identifier value can be introduced to represent all STAs; all remaining fields are completely consistent with the information in the channel reservation request frame; if the VR-STA does not agree to the channel reservation request of a V-STA, the reservation information of the V-STA is not included in the response frame; Step 4: Receive a channel reservation response frame; After the V-STA receives the channel reservation response frame of the VR-STA, if the channel reservation response frame agrees with the channel reservation request of the V-STA, the V-STA records the SP information of the channel reservation and plans to communicate with the VR-STA in the SP; After receiving the channel reservation response frame from VR-STA, NV-STA records the SP information of the channel reservation; Step 5: SP phase; Before the scheduled SP starts, all stations need to end the current data transmission to ensure that the channel is idle when the SP starts; NV-STA keeps silent from the start time of SP, and the silence time is the silence time indicated by the silence interval to avoid interfering with the scheduled transmission of V-STA and VR-STA; V-STA gives priority to transmitting the reserved frame type from the beginning of SP to ensure the timely transmission of key frames and reduce the impact of delay on video quality; if the reserved frame type is sent, other frame types are sent.

2. A computer program, characterized in that The computer program enables a computer to execute the method as claimed in claim 1.

3. An electronic device, characterized in that: include: Processor and memory; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the electronic device executes the method as claimed in claim 1.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method as claimed in claim 1 is implemented.

5. A chip, characterized in that: include: A processor, used to call and run a computer program from a memory, so that a device equipped with the chip executes the method as claimed in claim 1.

6. A computer program product, characterized in that The computer program product comprises a computer storage medium storing a computer program, wherein the computer program comprises instructions executable by at least one processor, and when the instructions are executed by the at least one processor, the method according to claim 1 is implemented.

Images