KR101038521B1 - Cross-layer method for improving the quality of video transmission service over heterogeneous networks - Google Patents

Abstract

The present invention relates to a method for improving video transmission quality over heterogeneous networks according to a cross-layer scheme, wherein the video server compresses the 'video data' according to the priority of the video data partitioning information by the CBQ means. (A) differentially transmitting to the WiMAX base station, transmitting the 'video data' received by the WiMAX base station to the client so as to match the priority of the 'video data partitioning information', and the client transmitting the 'video' And (c) decoding the 'video data' according to the priority of the data partitioning information.

According to the present invention as described above, after assigning a parameter related to the priority of each video traffic according to the data partitioning scheme of the H.264 video coding scheme, the information on the type of partitioning, the WiMAX corresponding to the lower layer and the class-by-class standby By transmitting to a CBQ-based WAN, it is possible to maximize the quality improvement of a downlink video transmission service and a video transmission service in a heterogeneous network interworking with a wired network and a WiMAX wireless network.

Cross Layer, Cross Layer, WiMAX, WiMAX, Class Queue, CBQ, Class Based Queuing, H.264 Data Partitioning, Quality, Quality of Service

Description

CROSS-LAYER METHOD FOR IMPROVING THE QUALITY OF VIDEO TRANSMISSION SERVICE OVER HETEROGENEOUS NETWORKS}

The present invention relates to a method for improving video transmission quality over heterogeneous networks according to a cross-layer technique. More particularly, the present invention relates to determining a transmission priority for improving video transmission service quality by transmitting a service quality request in an application layer to a lower layer. Accordingly, the present invention relates to a technique for minimizing video packet loss and delay time variation.

In general, since video data encoded in an application is encoded and transmitted without considering network conditions, quality tends to be degraded according to network conditions. In particular, even though video data transmitted through a wireless network has data priorities for decoding, it is difficult to provide a constant quality of service because they all have the same priority during network transmission.

In connection-oriented networks, such as Wide Area Network (WAN) and World Interoperability for Microwave Access (WiMAX) with Class-Based Services (CBQ), the entire video traffic can Since the method of processing video traffic by assigning only the priority of the service queue and only the service queue is common, a queue overflow phenomenon occurs when a large amount of traffic is delivered.

For video transmission considering network conditions, methods such as Active Queue Management (hereinafter referred to as 'AQM') are applied to adjust the rate of video traffic transmitted from the video server according to network conditions. J. Lakkakorpi, A. Sayenko, O. Karhula, J. Moilanen's paper Active Queue Management for Reducing Downlink Delays in WiMAX (IEEE 66 ^th Vehicular Technology Conference, Sept., 2007).

However, in the case of AQM-applied methods, additional network overhead is generated for rate control, and additional resource reservation is required when there are many targets to be processed. In addition, when the network is delayed, transmission of data for rate control may be delayed, which causes a problem of synchronization of rate parameters between the video server and the base station.

In the case of the AQM scheme, cross-layer architectures for transferring information between layers have been proposed because there are limitations in ensuring video transmission quality due to the problems described above.

Meanwhile, a method of guaranteeing the quality of service by mapping parameters of IEEE 802.11e Enhanced Distributed Channel Access (EDCA) and H.264 / Advanced Video Coding (AVC) data partitioning is assured by A. Ksentini, M. Naimi, and A. Gueroui. Was published in Toward an improvement of H.264 video transmission over IEEE 802.11e through cross-layer architecture (IEEE Communications Magazine, Jan. 2006).

According to the document, H.264 / AVC data partitioning divides the data of a video slice into partitions according to importance and delivers the information related to the importance to lower layers to ensure a different transmission quality according to the information contained in the partition. The method has been proposed.

Through this, after the priority is given according to the information contained in the video data, differential data transmission is possible, which plays a key role in improving video quality when decoding the video data.

Therefore, the cross-layer technique improves the overall video transmission quality by improving the quality of service for high-priority traffic only by modifying the portion that processes video traffic without major changes in the existing network structure.

However, the cross-layer technique as described above has limitations for the following two aspects.

First, since the method is a proposal limited to a contention-based network such as IEEE 802.11e EDCA, in a class-based queuing (CBQ) or a connection-oriented network such as IEEE 802.16d WiMAX. Difficult to apply In the connection-oriented scheme, there is a difference in the control of queue scheduling and connection request processing. Therefore, it is difficult to use the scheme proposed in the contention-based scheme as it is.

Second, it is difficult to further classify according to the characteristics of the packet by extracting only the information according to priority among the header information of H.264 / AVC. That is, by delivering only information based on importance, not packet type information, to the lower layer, different types of packets are processed at the same level, which causes problems related to scalability later.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to assign a priority parameter to each video traffic by using a data partitioning technique among H.264 video encoding methods, and then, a type of partitioning. By transmitting the information about the WiMAX and CBQ-based WAN corresponding to the lower layer, the purpose is to provide a quality improvement of the downlink video transmission service.

Another object of the present invention is to provide a video transmission service in a heterogeneous network interworking with a CBQ-based wired network and a WiMAX wireless network using H.264 data partitioning information to ensure continuous service quality between heterogeneous networks. The purpose is to improve quality.

In order to achieve the above technical problem, a method of improving video transmission quality in heterogeneous networks according to the cross-layer scheme of the present invention includes a method of improving video data compressed by a video server to a video data partitioning information by a CBQ means. (A) transmitting each priority to the WiMAX base station in differentiation, and transmitting the 'video data' received from the WiMAX base station to the client so as to match the priority of the 'video data partitioning information', And (c) the client decoding the 'video data' according to the priority of the 'video data partitioning information'.

Also, in the step (a), the H.264 NAL layer (hereinafter referred to as 'NAL layer') of the video server is assigned to the H.264 VCL layer (hereinafter referred to as 'VCL layer'). (A-1) dividing (partitioning) the compressed video data, and inserting NAL header information including 'video data segmentation type information' into the header of the segmented video data by the NAL layer of the video server. (A-2) generating a 'data', and (a-3) generating a 'RTP / UDP packet' by inserting 'NAL video data' into the RTP / UDP header by the RTP / UDP layer of the video server. (A-4) in which the IP layer of the video server inserts an 'RTP / UDP packet' into an IP header to generate an 'IP packet', and the CBQ means of the video server is assigned to the 'IP packet'. (A-5) inserting a MAC (Media Access Control) header and reading 'video data partition type information' included in the 'IP packet', and the video server A determination result of steps (a-6) and (a-6) of determining whether the video data partition type information included in the 'IP packet' is 'partition A'; When the 'video data partition type information' included in the 'IP packet' is 'partition A', the CBQ means of the video server assumes the 'IP packet' as the first priority and uses the WiMAX base station through the wired network. (A-7) step of transmitting to.

In addition, when the determination result of step (a-6) indicates that the 'video data partition type information' included in the 'IP packet' is not 'partition A', the graded waiting command (CBQ) means of the video server determines the 'IP packet'. A) a second priority, and transmitting to the WiMAX base station through the wired network (a-8).

In addition, step (b) is a step (b-1) in which the WiMAX base station determines whether the 'video data partitioning information' included in the 'IP packet' received from the video server through the wired network is 'partition A'; As a result of determining in step (b-1), when the 'video data segmentation information' included in the 'IP packet' is 'partition A', the WiMAX base station derives the 'IP packet' as the first priority and then the first priority. (B-2) storing the rtPS in a real-time polling service (RTPS) queue, and transmitting the 'IP packet' derived from the first priority to the client through the WiMAX wireless network (b-). 3) step.

In addition, when the determination result of step (b-1) indicates that the video data partitioning information included in the IP packet is not Partition A, the WiMAX base station derives the IP packet as a second priority, (B-4) storing the priority in a non-real-time polling service (nrtPS) queue, and processing the 'IP packet' derived from the second priority to the client through the WiMAX wireless network. (B-5) transmitting.

Also, in the step (c), the IP layer of the client receives the 'IP packet' from the WiMAX base station through the WiMAX wireless network, reads the header of the 'IP packet', and decodes it into 'RTP / UDP packet' (c-1). (C-2) the RTP / UDP layer of the client reads the header of the 'RTP / UDP packet' and decodes it into 'NAL video data', and the NAL layer of the client sets the header of the 'NAL video data'. (C-3) decoding 'NAL video data' into 'video data' so as to match 'video data partition type information' by reading 'video data partition type information' included in the 'VCL layer' of the client. If the 'video data' is not damaged, the client plays the 'video data' (c-5). ) Step.

In addition, as a result of the determination in step (c-4), if the 'video data' is corrupted, the client determines whether the 'video data' is decoded from the 'IP packet' having the first priority by an error concealment / hidden technique. As a result of the determination of steps (c-6) and (c-6), when the 'video data' is decoded from the 'IP packet' having the first priority, the client corrects the 'video data'. And (c-7) restoring.

If the determination result of step (c-7) indicates that the video data has not been decoded from the IP packet having the first priority, the client discards the video data to the video server via the WiMAX base station. (C-8) requesting retransmission of 'video data'.

According to the present invention as described above, after assigning a parameter related to the priority of each video traffic according to the data partitioning technique of the H.264 video encoding scheme, based on the WiMAX and CBQ corresponding to the information on the type of partitioning By transmitting to the WAN, there is an effect of providing a quality improvement of the downlink video transmission service.

In order to ensure continuous service quality between heterogeneous networks, we improve the quality of video transmission service in heterogeneous networks interworking with wired-by-class (CBQ) based wired networks and WiMAX wireless networks using H.264 data partitioning information. It is effective to maximize.

Specific features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, terms and words used in the present specification and claims are to be interpreted in accordance with the technical idea of the present invention based on the principle that the inventor can properly define the concept of the term in order to explain his invention in the best way. It should be interpreted in terms of meaning and concept. It is to be noted that the detailed description of known functions and constructions related to the present invention is omitted when it is determined that the gist of the present invention may be unnecessarily blurred.

1 is a block diagram showing a system for improving video transmission quality over heterogeneous networks according to a cross-layer scheme according to the present invention. As shown, the video server 100, the WiMAX base station 200, and the client 300 are shown. It is made to include.

Hereinafter, the description thereof will be omitted, but it is described that the WiMAX base station 200 according to the present invention includes a function of a router, but the present invention is not limited thereto, and the WiMAX base station 200 includes a router function. If not, video traffic type information can be transmitted to a medium access control (MAC) layer. That is, continuous video transmission in a wide area network (WAN) and WiMAX base station 200 to which Class-Based Queuing (CBQ) is applied using only information transmitted to the MAC layer. Provide service quality guarantees.

In addition, the video transmission quality improvement system S on the heterogeneous network according to the cross-layer scheme according to the embodiment of the present invention may not use a real time protocol (RTP) or use a transmission control protocol (TCP).

In addition, the WiMAX base station 200 of the present invention described below means a base station that includes a routing function and has a wired and wireless interface, and the base station capable of traffic mapping between the WAN wired interface and the WiMAX wireless interface through a predefined mapping table. Say.

As shown in FIG. 1, the video server 100 performs WiMAX through a wide area network (WAN) to which a video packet obtained by encoding generated video data through an H.264 / AVC data partitioning scheme is applied with a queuing queue (CBQ). Transmit to base station 200.

In this case, encoding of video data inserts information about a partition type into each layer protocol header and has a differential priority according to partition type information inserted into a packet header. For example, when the partition type information is 'A', it is preferable that the rank-by-class queue (CBQ) has a high priority and has a hypocritical order in the order of 'B' ... 'Z'.

In addition, the WiMAX base station 200 receives the video packets differentiated according to the priority from the video server 100 via the wide area network (WAN) to which the CBQ is applied, and according to the predefined mapping table. It transmits to the client 300 via the WiMAX wireless network (10).

In addition, the WiMAX base station 200 includes a wired interface and a WiMAX wireless interface of a wide area network (WAN) to which a classification queue (CBQ) is applied, and performs a routing function, a traffic connection processing function, and a scheduling function between traffics.

Then, the client 300, but decodes the video packets received from the WiMAX base station 200 via a wireless network 10, the bandwidth allocated in the WiMax base station 200 (e.g., 540kb / s) video received in accordance with the The video data is read by decoding the packet . That is, the client 300 is based on a point to multi point (PMP) method, and manages video traffic generated when the video packet is received.

2 is a diagram illustrating an H.264 / AVC data type used in a video transmission quality improvement system (S) on a heterogeneous network according to a cross-layer scheme according to the present invention, a graded queue (CBQ) -based wide area network (WAN), and IEEE A diagram illustrating a mapping structure of 802.16d WiMax parameters.

Priorities in a wide area network (WAN) to which a CBQ is applied are defined using numbers, and high priority is usually assigned to voice traffic in which real time is important. The video traffic of the present invention is not processed by giving priority to a conventional method, but the traffic is processed by differentiating a plurality of videos according to the importance of information included in the video packet .

In the case of WiMAX, there are four service classes to handle traffic. In the case of video traffic, since it is a large-capacity transmission using a variable length packet that requires real time, rtPS (real-time) is generally the next priority of voice traffic. Polling Service).

According to the present invention, processing is performed by differentiating between rtPS and ntPS (non-real-time polling service) according to the importance of information included in the video packet , thereby providing the effect of distributing video traffic and high priority traffic. As a result, the quality of the video transmission service is improved.

3 is a diagram illustrating a process of transmitting partition information of H.264 / AVC to a lower layer by a video server 100 of a video transmission quality improving system S on a heterogeneous network according to a cross-layer scheme according to the present invention, and the transmitted partition information. A header generation flowchart describing the process stored in the protocol header of each layer.

As shown in FIG. 3, since the partition A packet includes data of high importance such as vector information, quantity information, and slice header information, which are essential for decoding, the highest rank queue (CBQ) priority among video data. To assign.

In addition, since the partition B packet includes intra macro block related information, and the party line C packet includes inter macro block related information, the partition B packet has higher priority than the partition C packet or H.264. From the point of view of error concealment of / AVC, partition B packet and partition C packet are located at the same position and are processed with the same priority.

As such, partition A packets having a higher priority than partition B packets and partition C packets are given more transmission opportunities, thereby increasing transmission arrival rate and reducing delay time of each packet. In addition, partition B packets and partition C packets show relatively lower performance than partition A packets, but avoid queue overflow when the network conditions deteriorate when compared to all conventional video traffic processing as one priority. As a result, improved performance is achieved.

As shown in FIG. 3, the H.264 NAL layer of the video server 100 converts information on a NAL unit type (hereinafter, referred to as 'NUT') into an RTP / UDP, IP, and MAC header corresponding to a lower layer. Determining the priority of each class queue (CBQ) according to the NUT information received by the wired network interface of the video server 100, and differentially transmits the video packet to the WiMAX base station (CBQ) priority 200).

Meanwhile, FIG. 4 shows that the WiMAX base station 200 of the video transmission quality improvement system S on the heterogeneous network according to the loss layer scheme according to the present invention transmits through the wide area network (WAN) according to the priority queue for each grade (CBQ). The received video packet is divided into service classes based on the mapping standard of FIG. 2 and then transmitted to the client 300 through a wireless link.

The IEEE 802.16d WiMAX base station 200 reads the IP header information and the MAC header information of the packet transmitted through the wired network. In most cases, the IEEE 802.16d WiMAX base station 200 receives the packets for the subscriber station located on the wireless network.

In the wired network, packets that are differentially transmitted according to the priority of the class queue (CBQ) according to the priority are divided into respective WiMAX classes according to the mapping table defined in the WiMAX base station 200 and transmitted to the wireless network.

Since WiMAX is a connection-oriented network, a queue of a corresponding service class is created when the first packet for an arbitrary client arrives. When traffic for multiple clients is delivered at the same time, it has the same level. Maintain multiple service class queues. Here, service class queues of the same level compete in the same situation in wireless transmission, and the competition increases as the number of queues increases and the number of queues is maintained for a long time.

For example, when a video traffic having a data rate of 540 kb is delivered to the WiMAX base station 200 through a wide area network (WAN) to which a gradual queue (CBQ) is applied, the header of the transmitted packet includes a partition type of the video data. Information is included, and when partition A, partition B, and partition C reach the WiMAX base station 200 at the same time, partition A is stored in a differentiated queue (rtPS) to store partition B and partition C (nrtPS). Will be sent more quickly.

Looking at the message flow of the process that the video traffic delivered to the WiMAX base station 200 is distributed to rtPS and nrtPS Service Class and processed with reference to the above description and FIG. 4 as follows.

Data having a transmission rank that is differentiated according to the priority of a class queue (CBQ) by the NUT information contained in the header of each packet is transmitted from the WiMAX base station 200 to the wireless network. The impact from the feature is more pronounced in the wired network, resulting in a lower packet delivery rate.

For this reason, packet retransmission and acknowledgment (Ack) occur frequently, resulting in a slower packet transmission rate compared to wired networks.

Accordingly, the present invention operates two queues according to the NUT information of each traffic by using the rtPS and nrtPS service classes in the WiMAX base station 200, so that a smaller amount of packets remain in each queue than in the related art. Particularly, since partition A can be processed more quickly than before, higher video quality can be achieved in view of the error concealment technique used in video decoding.

Meanwhile, FIG. 5 is a diagram illustrating a restoration procedure of a video packet finally reaching a client, and whether or not the arrival of partition A determines whether or not decoding is possible.

When partition A of the slice (frame) is delivered to the client, even when partition B or partition C is missing, error concealment or error recovery can be used to play in a degraded state. However, if partition A is missing, the slice is discarded because error concealment and recovery is impossible.

When the video transmission quality improvement system on the heterogeneous network according to the cross-layer technique according to the present invention as described above is summarized, the video server 100 converts the compressed 'video data' to the 'video data' through the CBQ means. According to the split information, each priority is differentially transmitted to the WiMAX base station 200.

In addition, the WiMAX base station 200 transmits the 'video data' received from the video server 100 to the client 300 to match the priority of the 'video data segmentation information'.

The client 300 decodes the video data received from the WiMAX base station 200 according to the priority of the video data partitioning information.

In this case, the information transmission between the video server 100 and the WiMAX base station 200 is made through a wired network, and the information transmission between the WiMAX base station 200 and the client 300 is made through a WiMAX wireless network. The present invention is not limited thereto, and may be transmitted by using a wired or wireless network.

In addition, the video server 100 and the WiMAX base station 200 exchange data in a communication in which a CBQ is applied, and the importance of each data is differentiated according to the CBQ.

In addition, network devices located between the video server 100 and the WiMAX base station 200 all identify the priority according to the ranking queue (CBQ), and prioritize the priority of the 'video data' according to the ranking queue (CBQ). Transmit differentially.

In addition, the WiMAX base station 200 stores a policy for classification of 'video data' according to the priority of each interface in the state of having a CBQ-based wide area network (WAN) and a WiMAX network interface. have.

A method of improving video transmission quality over heterogeneous networks according to the cross layer scheme using the system S will be described with reference to FIG. 6 as follows.

Hereinafter, the description thereof will be omitted, but the video server 100, the WiMAX base station 200, and the client 300 according to the present invention preferentially according to a graded queue (CBQ) through any one of a wired network and a WiMAX wireless network. Send and receive 'IP packets' with different ranks.

FIG. 6 is a flowchart illustrating a method for improving video transmission quality over heterogeneous networks according to a cross-layer scheme. As shown in FIG. 6, the video server 100 transmits the compressed 'video data' through a rank-by-class queue (CBQ) means. Different priorities are transmitted according to the data partition information 'to the WiMAX base station 200 (S100).

Subsequently, the WiMAX base station 200 transmits the received "video data" to the client 300 so as to match the priority of the "video data segmentation information" (S200).

Then, the client 300 decodes the 'video data' according to the priority of the 'video data segmentation information' (S300).

Specifically, referring to step S100, referring to FIG. 7, the H.264 NAL layer (hereinafter, referred to as a 'NAL layer') of the video server 100 is an H.264 VCL (Video Coding Layer) layer (hereinafter, referred to as “NAL layer”). In operation S110, the compressed video data is divided (partitioned) into a 'VCL layer'.

Subsequently, the NAL layer of the video server 100 inserts NAL (Network Astract Layer) header information (including 'video data segmentation type information') into the header of the divided video data to generate 'NAL video data' (S120). .

Subsequently, the RTP / UDP layer of the video server 100 inserts 'NAL video data' into the RTP / UDP header to generate a 'RTP / UDP packet' (S130).

Afterwards, the IP layer of the video server 100 inserts an RTP / UDP packet into an IP header to generate an IP packet (S140).

Subsequently, the CBQ means of the video server 100 inserts a MAC (Media Access Control) header into the 'IP packet' and reads the 'video data partition type information' included in the 'IP packet'. (S150).

Then, the graded queue (CBQ) means of the video server 100 determines whether the 'video data partition type information' included in the 'IP packet' is 'partition A' (S160).

As a result of the determination in step S160, when the 'video data partition type information' included in the 'IP packet' is 'partition A', the rank-by-class queue (CBQ) means of the video server 100 selects the 'IP packet'. Assuming the first priority and transmits to the WiMAX base station 200 through the wired network (S170).

On the other hand, when the determination result of step S160 indicates that the 'video data partition type information' included in the 'IP packet' is not 'partition A', the graded queue (CBQ) means of the video server 100 determines the ' The IP packet is assumed as the second priority and transmitted to the WiMAX base station 200 through the wired network (S180).

Specifically, referring to step S200 with reference to FIG. 8, whether or not the 'video data partitioning information' included in the 'IP packet' transmitted from the video server 100 through the wired network is 'partition A'. Determine (S210).

As a result of the determination in step S210, when the 'video data partition type information' included in the 'IP packet' is 'partition A', the WiMAX base station 200 derives the 'IP packet' as the first priority and 1 is stored in the rtPS (real-time Polling Service) queue to process the priority (S220).

Subsequently, the WiMAX base station 200 transmits the 'IP packet' derived as the first priority to the client 300 through the WiMAX wireless network (S230).

On the other hand, when the determination result of step S210 indicates that the video data partition type information included in the IP packet is not Partition A, the WiMAX base station 200 prioritizes the IP packet to the second priority. Derived into and stored in the nrtPS (non-real-time Polling Service) queue to process the second priority (S240).

Subsequently, the WiMAX base station 200 transmits the 'IP packet' derived as the second priority to the client 300 through the WiMAX wireless network (S250).

Specifically, referring to step S300 with reference to FIG. 9, the client 300 receives the 'IP packet' from the WiMAX base station 200 through the WiMAX wireless network, and the IP layer reads the header of the 'IP packet' to 'RTP'. / UDP packet '(S310).

Subsequently, the RTP / UDP layer of the client 300 reads the header of the 'RTP / UDP packet' and decodes it into 'NAL video data' (S320).

Subsequently, the NAL layer of the client 300 reads 'video data segmentation type information' included in the header of 'NAL video data' to match the 'NAL video data' with 'video data segmentation type information'. Decode by '(S330).

Behind the scenes, the VCL layer of the client 300 determines whether the 'video data' is damaged (S340).

As a result of the determination in step S340, when the 'video data' is not damaged, the decoded 'video data' is reproduced (S350).

On the other hand, when the determination result of step S340, when the 'video data' is damaged, it is determined whether the 'video data' decoded by the error concealment / concealment technique is decoded from the 'IP packet' having the first priority (S360).

As a result of the determination of step S360, when the decoded 'video data' is decoded from the 'IP packet' having the first priority, the 'video data' is corrected and restored (S370).

On the other hand, when the determination result of step S360, when the decoded 'video data' is not decoded from the 'IP packet' having the first priority, discard the 'video data' or the video server via the WiMAX base station 200 The server 100 requests retransmission of the 'video data' (S380).

As described above and described with reference to a preferred embodiment for illustrating the technical idea of the present invention, the present invention is not limited to the configuration and operation as shown and described as described above, it is a deviation from the scope of the technical idea It will be understood by those skilled in the art that many modifications and variations can be made to the invention without departing from the scope of the invention. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

1 is a block diagram showing a system for improving video transmission quality over heterogeneous networks according to a cross layer technique according to the present invention.

2 is a diagram illustrating an H.264 / AVC data type used in a video transmission quality improvement system (S) on a heterogeneous network according to a cross-layer scheme according to the present invention, a graded queue (CBQ) -based wide area network (WAN), and IEEE A diagram showing the mapping structure of the 802.16d WiMax parameter.

3 is a diagram illustrating a process of transmitting partition information of H.264 / AVC to a lower layer by a video server 100 of a video transmission quality improving system S on a heterogeneous network according to a cross-layer scheme according to the present invention, and the transmitted partition information. Header generation flowchart describing the process stored in the protocol header of each layer.

4 is a video received by a WiMAX base station 200 of a video transmission quality improvement system S on a heterogeneous network according to a loss layer scheme according to a priority queue (CBQ) according to a class, according to the present invention. FIG. 2 illustrates that packets are classified into service classes based on the mapping standard of FIG. 2 and then transmitted to the client 300 through a wireless link.

5 is a diagram illustrating a restoration procedure of a video packet finally received by a client 300 of a video transmission quality improvement system S on a heterogeneous network according to a loss layer scheme according to the present invention.

Figure 6 is a flow chart showing a color laser printer discrimination method by analyzing the halftone structure according to the present invention.

** Description of symbols for the main parts of the drawing **

S: Video Transmission Quality Improvement System on Heterogeneous Network by Cross-Layer Technique

100: video server 200: WiMAX base station

300: client

Claims (8)

A method for improving video transmission quality on heterogeneous networks by cross layer technique, (a) the video server transmitting the compressed 'video data' to the WiMAX base station in order of different priorities so as to correspond to the 'video data partitioning information' under the control of the CBQ means; (b) transmitting the 'video data' received by the WiMAX base station to a client so as to match the priority of the 'video data partitioning information'; And (c) the client decoding the 'video data' according to the priority of the 'video data partitioning information'; The video transmission quality improvement method on heterogeneous networks according to the cross-layer technique comprising a. The method of claim 1, In step (a), (a-1) A H.264 NAL layer (hereinafter, referred to as a 'NAL layer') of the video server is compressed into an H.264 VCL (Video Coding Layer) layer (hereinafter referred to as a 'VCL layer'). Dividing (partitioning) video data '; (a-2) generating a 'NAL video data' by inserting NAL header information including 'video data partition type information' into a header of the 'video data' by the NAL layer of the video server; (a-3) generating a 'RTP / UDP packet' by inserting the 'NAL video data' into an RTP / UDP header by an RTP / UDP layer of the video server; (a-4) generating an 'IP packet' by inserting an 'RTP / UDP packet' into an IP header by an IP layer of the video server; (a-5) The CBQ means of the video server inserts a MAC (Media Access Control) header into the 'IP packet' and the 'video data partition type information included in the' IP packet '. Reading '; (a-6) determining, by the CBQ means of the video server, whether the 'video data partition type information' included in the 'IP packet' is 'partition A'; And (a-7) As a result of the determination in step (a-6), when the 'video data partition type information' included in the 'IP packet' is 'partition A', the rank-by-class queue (CBQ) means of the video server Assuming the 'IP packet' as a first priority and transmitting the IP packet to the WiMAX base station through a wired network; The video transmission quality improvement method on heterogeneous networks according to the cross-layer technique comprising a. The method of claim 2, (a-8) When the 'video data partition type information' included in the 'IP packet' is not 'partition A', as a result of the determination in the step (a-6), a rank-by-class queue (CBQ) means of the video server Assuming the 'IP packet' as a second priority and transmitting the IP packet to the WiMAX base station through a wired network; The video transmission quality improvement method on heterogeneous networks according to the cross-layer technique comprising a. The method of claim 1, In step (b), (b-1) determining, by the WiMAX base station, whether 'video data partitioning information' included in an 'IP packet' received from the video server through a wired network is 'partition A'; (b-2) As a result of the determination in step (b-1), when the 'video data partitioning information' included in the 'IP packet' is 'partition A', the WiMAX base station transmits the 'IP packet' to the first packet; Deriving a priority and storing the first priority in a real-time polling service (rtPS) queue that processes the first priority; And (b-3) transmitting, by the WiMAX base station, an 'IP packet' derived as a first priority to the client through a WiMAX wireless network; The video transmission quality improvement method on heterogeneous networks according to the cross-layer technique comprising a. The method of claim 4, wherein (b-4) In the determination result of step (b-1), if the 'video data partitioning information' included in the 'IP packet' is not 'Partition A', the WiMAX base station removes the 'IP packet'. Deriving a second priority and storing the second priority in a non-real-time Polling Service (nrtPS) queue that processes the second priority; And (b-5) transmitting, by the WiMAX base station, an 'IP packet' derived as a second priority to the client through a WiMAX wireless network; The video transmission quality improvement method on heterogeneous networks according to the cross-layer technique comprising a. The method of claim 1, In step (c), (c-1) receiving, by the IP layer of the client, an 'IP packet' from the WiMAX base station through the WiMAX wireless network, reading a header of the 'IP packet' and decoding the header into an 'RTP / UDP packet'; (c-2) reading, by the RTP / UDP layer of the client, the header of the 'RTP / UDP packet' and decoding it into 'NAL video data'; (c-3) the NAL layer of the client reads 'video data segmentation type information' included in a header of the 'NAL video data' to match the 'NAL video data' with the 'video data segmentation type information' Decoding to 'video data'; (c-4) determining whether the 'video data' is damaged by the VCL layer of the client; And (c-5) if the 'video data' is not damaged as a result of the determination in step (c-4), the client playing the 'video data'; The video transmission quality improvement method on heterogeneous networks according to the cross-layer technique comprising a. The method of claim 6, (c-6) When the 'video data' is damaged as a result of the determination in the step (c-4), the 'IP data' having the first priority of the 'video data' by the client in error concealment / hidden technique; Determining whether it has been decrypted from; And (c-7) when the determination result of the step (c-6) indicates that the 'video data' is decoded from the 'IP packet' having the first priority, the client corrects the 'video data' and Restoring; The video transmission quality improvement method on heterogeneous networks according to the cross-layer technique comprising a. The method of claim 7, wherein (c-8) When the determination result of the step (c-6) indicates that the 'video data' is not decoded from the 'IP packet' having the first priority, the client discards the 'video data' or the Requesting retransmission of the 'video data' to the video server via a WiMAX base station; The video transmission quality improvement method on heterogeneous networks according to the cross-layer technique comprising a.

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