KR20110138122A - Method and apparatus for determining a transmission path based on user perceived end-to-end quality of service - Google Patents

Abstract

PURPOSE: A transmission line determination method based on user side termination service quality in a wireless communication system and apparatus thereof are provided to determine a transmission line based on user side service quality. CONSTITUTION: A measurement unit(110) acquires the service quality of a user side. A control unit(130) selects one or more transmission lines which satisfy the request of a user according to a fixed standard. The measurement unit and the control unit are located to a user terminal. The measurement service includes a quality measurement unit(101) or a network search unit(105). The service quality measurement unit measures the user side service quality. The network searching unit searches the satisfaction of the user side quality and measures searching information.

Description

METHOD AND APPARATUS FOR DETERMINING A TRANSMISSION PATH BASED ON USER PERCEIVED END-TO-END QUALITY OF SERVICE}

The present invention relates to a method and apparatus for determining a transmission path in a wireless communication system, and more particularly, to a method and apparatus for a user terminal to proactively determine a transmission path based on a quality of service (QoS) at a network end. will be.

Multi-homing technology refers to a technology that enables a network or a node to receive a network access service through connection with multiple networks. The multi-homing technology can effectively provide errors prevention, service distribution, and the like, which are difficult to provide only by a single connection when connecting to a network, and have the advantage of being able to change the connection link to a political and economically advantageous link as well as supporting mobility. The multi-homing technology has been widely used in a wired network using IPv4.However, according to the rapid progress of the wireless communication technology, the multi-homing technology can be used in a wireless network while enabling the user terminal network access using one or more wireless access technologies. Various studies are being made for this purpose.

Looking at the recent trend of the multi-homing technology in the wireless network, a study to overcome the decrease in the quality of service due to the packet loss and transmission delay that occurs frequently in the process of providing real-time service through the wireless channel, As the user terminal may be connected to one or more wireless networks, the multi-homing technique is also used for mobility guarantee technology for the user terminal to determine a communication path.

Therefore, although the technical problem for applying the multi-homing technology in the wireless network has been largely solved, the user terminal determines which access network is the optimal access network and uses the information to determine the optimal transmission path that the user can satisfy. In many cases, only heuristic research is being conducted.

Considering the representative research cases related to the multi-homing technology, a multiple attribute decision making (MADM) algorithm for collecting network information about available heterogeneous networks for service transmission and making an optimal network decision by a user terminal has been proposed. A performance reporting network decision algorithm has been proposed to predict the current network conditions to satisfy bandwidth and to balance the load between networks. In another case, a smart decision algorithm is conducted that studies the available user terminal interface, system information, and a score function that takes into account the user's preferences and performs the handover at the optimal time timing using the best interface. Proposed.

In another research case related to the multi-homing technology, the state information of the network, system resource usage, user preference, and service request are considered by studying a system structure of a user terminal supporting effective mobility and roaming service in a heterogeneous network integration environment. A user-oriented intelligent network selection algorithm has been proposed, and an algorithm for actively communicating with a wireless LAN when a user terminal receives a message from a cellular network to reduce power consumption of the user terminal has also been proposed. have. Hereinafter, in the present specification, a network or transmission path determination algorithm and a network or transmission path selection algorithm will be collectively referred to as a network or transmission path determination algorithm.

However, the above-mentioned studies related to the determination of the network or transmission path of the user terminal consider the user's preference information, but do not consider the user quality of service (hereinafter referred to as "user side service quality") at the network end. When a network or transmission path that is currently connectable is recognized, unnecessary network load and quality of service may be reduced by performing a network or transmission path determination algorithm unconditionally.

In addition, since existing network or transmission path determination algorithms determine a network or transmission path in consideration of user preferences or some service quality indexes, there is a need for a method for determining an optimal network or transmission path in terms of users.

The present invention provides a method and apparatus for determining a transmission path based on user side quality of service at a network end in a wireless communication system.

The present invention also provides a method and apparatus for determining a transmission path with a minimum required radio resource based on user side quality of service at a network end in a wireless communication system.

In addition, the present invention provides a method and apparatus for determining a transmission path based on a quality of service required in a wireless communication system and a user side quality of service at a network end.

The present invention also provides a method and apparatus for determining multiple transmission paths based on user side quality of service at a network end in a wireless communication system.

In a method of determining a transmission path in a wireless communication system according to an embodiment of the present invention, a process of acquiring user side service quality that can be provided for each path and determining at least one transmission path according to a predetermined criterion based on the user side service quality It includes the process of doing.

In addition, a communication apparatus for determining a transmission path of a service in a wireless communication network according to an embodiment of the present invention includes a measuring unit for obtaining a user side service quality that can be provided for each path, and a user side service quality required by a user according to a predetermined standard. And a control unit for selecting at least one transmission path that satisfies.

According to an embodiment of the present invention, the user terminal periodically or aperiodically provides information on required service quality information, signal strength for each radio access technology (RAT), modulation and coding scheme, and the like in a service flow to which the UE is connected. If the user side service quality is not satisfied, and if the user side service quality is not satisfied, the user terminal can check the wireless transmission path and transmission scheme that can be proactively connected, and determine an optimal wireless transmission path.

In addition, according to an embodiment of the present invention, the optimal radio transmission is calculated by integrating the individual radio transmission paths for multipath transmission as well as the individual radio transmission paths capable of connecting the required radio resources for satisfying the user side service quality at the network end. The route can be determined.

In addition, according to an embodiment of the present invention, not only provides a transmission path determination method based on user side quality of service for a single transmission path, but also improves the end quality of service at the user side by using multiple paths for a service required by a user. Can provide.

)를 도출하는 방식을 설명하기 위한 도면,
도 4는 본 발명의 실시 예에 따라 지연 한계를 만족시키기 위한 요구 전송 속도를 도출하기 위한 이중 토큰 버켓 모델을 설명하기 위한 도면,
도 5은 본 발명의 실시 예에 따라 단일 전송 경로를 결정하는 방법을 나타낸 순서도,
도 6는 본 발명의 실시 예에 따라 다중 전송 경로를 결정하는 방법을 나타낸 순서도.1 is a block diagram illustrating a configuration of an apparatus for selecting and determining a transmission path according to an embodiment of the present invention;
FIG. 2 is a block diagram functionally showing a configuration of a request resource calculator in FIG. 1; FIG.
3 illustrates a request rate used in the calculation of the equivalent rate in accordance with an embodiment of the present invention.

To explain how to derive)
4 is a diagram illustrating a dual token bucket model for deriving a required transmission rate for satisfying a delay limit according to an embodiment of the present invention;
5 is a flowchart illustrating a method of determining a single transmission path according to an embodiment of the present invention;
6 is a flowchart illustrating a method of determining multiple transmission paths according to an embodiment of the present invention.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

An embodiment of the present invention to be described below uses the measurement results of user side service quality as well as the service quality measurable for each layer in providing user services to optimize the determination of the transmission path, and also to determine the transmission path of the user terminal. The present invention proposes a method and apparatus for determining a transmission path through which a user terminal predominantly transmits a service by providing a single integrated transmission path determination criterion by combining various service quality indicators required for each service.

In addition, an embodiment of the present invention triggers a transmission path determination algorithm according to whether user side service quality is satisfied, and is required in consideration of received signal strength and spectral efficiency according to modulation and coding scheme as well as required quality for each service. The present invention proposes a method and apparatus for quantitatively calculating resources and determining a transmission path having a minimum calculated calculated radio resource.

In addition, an embodiment of the present invention, if a path that satisfies the service cost, user preference, and service quality, as well as quantitatively calculated radio resources is found, satisfies a new transmission path when a criterion more than a predetermined value is satisfied than the current transmission path. A method and apparatus for the determination are proposed.

Prior to the detailed description of the present invention, terms used in the present invention are first defined.

First, "Access Technology" is a communication interface technology for connecting a user terminal and a wireless network or a wired network. The access technology includes a wireless access technology and a wired connection technology. The radio access technology (RAT) is an air interface technology that allows a user terminal to be connected to a base station such as a node B and an access point (AP) of a wireless network through a wireless link. The wireless access technology includes cellular access technology defined in 3GPP (3rd Generation Partnership Project), 3GPP2, etc., Wireless Local Area Network (WLAN) technology defined in IEEE 802.11, Metropolitan Area Network (MAN) technology defined in IEEE 802.16e, A typical example is a personal area network (PAN) technology defined in IEEE 802.15. The wired access technology may be a representative example of IEEE 802.3 Ethernet.

Next, in the present invention, "user side service quality" will be understood as a service quality affecting a user's communication satisfaction when the user uses at least one communication service. At this time, communication satisfaction includes sensory satisfaction and mental satisfaction, and sensory satisfaction is satisfaction that affects physical sensations such as sight, hearing, and smell. For example, the satisfaction that affects hearing depends not only on network dependent factors such as transmission delay and packet loss, but also on non-network factors such as transmit and receive noise, quantization distortion, and echo. Satisfaction affecting the visual quality is determined not only by network dependent factors such as packet loss, transmission delay, and transmission delay difference, but also by non-network factors such as screen deterioration and disconnection. Satisfaction that affects both visual and auditory hearing is the degree of synchronization between video and audio.

Mental satisfaction is satisfaction that affects mental sensations such as waiting, boredom, and utility. For example, satisfaction with boredom and wait is determined by factors such as page response time, file download time, and image buffering time. Satisfaction affecting utility is determined by factors such as file transfer speed and traffic transmission delay.

Communication satisfaction can be expressed through measurement data of subjective evaluation such as MOS, and can be used through objectification of subjective satisfaction.

In addition, the user side service quality includes not only service quality that can be recognized by the user, but also service quality that can be measured for each layer.

In addition, the service quality of the user side includes not only the service quality directly measured by the user terminal but also the service quality acquired through the network. In the present specification, "end quality of service" is a measurable quality of service between network elements that are terminated in pairs in each layer. Thus, "user-side quality of service" is also understood to include "end quality of service".

The user-side quality of service may include, for example, various quality of service such as R value, a perceptual speech quality measure (PSQM), a perceptual evaluation of speech quality (PESQ), a video quality measurement (VQM), a page response time, and the like. Can be measured using indicators. The end quality of service may be measured using, for example, end transmission delay, end packet loss, end transmission speed, signal strength, and the like.

Specifically, the user side service quality has a predictable characteristic, and thus the user side service quality may be derived by combining various service quality indicators and end service quality. For example, the service quality index for measuring the user-side service quality may be described. For voice services, a Mean Opinion Score (MOS), an R-value, and the like may be used.

Here, the MOS is a subjective quality of service indicator, but the R value is a value that can be directly measured by the user terminal and can be used by mapping the R value with the MOS. In the case of streaming service, VQM (Video Quality Measurement), and in the case of web service, page response time may be used as a service quality index for measuring the user side service quality.

In the voice service, the user side quality of service may be measured by using objective service quality indicators such as the Perceptual Speech Quality Measure (PSQM), the Perceptual Evaluation of Speech Quality (PESQ), as well as the MOS and R values. In the service, the end service quality may be measured using a service quality index such as a peak signal to noise ratio (PSNR), a video quality measurement (VQM), or the like.

Referring to the service quality indicators available in the present invention, it is shown in Table 1 below. The service quality indicators exemplified in Table 1 below are examples, and various service quality indicators capable of measuring user side service quality at a network end may be used.

In addition, the end service quality that can be measured at a lower layer of the network end may be measured by considering end transmission delay, end packet loss, end throughput, end transmission speed, signal strength, and packet delay variation as individual service quality indicators.

Next, the application layer is the highest layer in the communication layer structure, and the transport layer is the layer located below the application layer in the communication layer structure.

Next, the "quality of the received signal" may be represented using a Signal to Noise Ratio (SNR), a Signal to Interference plus Noise Ratio (SINR), and the like, and the "Service Flow" may be a user terminal for providing a service required by a user. Means a flow of a service packet defined between a server (or a base station) of a network providing a service. The service flow may be defined through an IP address and a port number used in the transmission / reception apparatus.

An access network (AN) may be defined as a network connecting a user terminal to a backbone network using a wired or wireless access technology. For example, in 3GPP, a network having Node-B and RNC (Radio Network Controller) as a network element may be defined as an access network, and the access network includes a Serving GPRS Support Node (SGSN) and a Gateway GPRS Support Node (GGSN). It is connected to the backbone network through the core network.

Next, in the embodiment of the present invention, "Effective Bandwidth", which is calculated when determining a transmission path, means a transmission speed required to satisfy a required quality index for each service. The required quality indicators for each service may include, for example, transmission delay, packet loss, and transmission rate in the case of a voice service, and transmission delay, packet loss, average and maximum transmission rates, and maximum burst size may be considered in the case of a live streaming service. have.

Next, "transmission path" means a communication path of a wired or wireless network in which a packet for user service is transmitted. In the embodiment of the present invention, the transmission path will be described as being divided into a single transmission path and a multiple transmission path. . In addition, when a path for transmitting a packet for a user service is different in the same wireless network, it may be defined as another transmission path.

Next, "spectrum efficiency" is defined as the number of bits that can be transmitted per unit bandwidth according to signal quality and modulation and coding scheme. The spectral efficiency is defined according to the type of wireless network as shown in Table 2 below. In Table 2 below, IEEE 802.16e, IEEE 802.11, LTE and the like are representative of a representative wireless network, it should be noted that the transmission path determination method of the present invention is not limited to the illustrated wireless network of <Table 2>. will be.

Lastly, the user terminal defined in the present invention means various terminal devices that can communicate wirelessly, and representative examples include mobile terminals such as mobile phones, PDAs, laptops, and desktop PCs using a wireless LAN. It may be included in the user terminal. That is, the user terminal includes not only a mobile terminal but also various fixed terminals that can be connected to a wireless communication system.

Next, a device configuration provided in a user terminal to provide a method for determining a transmission path using a user side service quality according to an exemplary embodiment of the present invention will be described with reference to FIG. 1.

1 is a block diagram illustrating a configuration of an apparatus for determining a transmission path according to an exemplary embodiment of the present invention. In FIG. 1, elements constituting reference numerals 101 to 109 illustrate an example configuration, and the apparatus of FIG. 1 may be configured with at least one functional block including a control unit by selectively combining the elements.

The apparatus of FIG. 1 includes a service quality measuring unit 101 for measuring user side service quality, a service quality management unit 103 for storing and providing required quality information for each service, and access network according to an embodiment of the present invention. , The network search unit 105 for obtaining information related to access technology, the amount of radio resources required per single transmission path using the measurement result of the user-side service quality, the request quality information for each service, and the information obtained through the network search. Or a request resource calculation unit 107 for calculating the amount of required radio resources for each of the multiple transmission paths, and an access network and a transmission path having a minimum amount of required radio resources based on the calculated amount of required radio resources. It includes a network path determiner 109 to determine. In the embodiment of FIG. 1, the service quality measuring unit 101, the service quality managing unit 103, and the network searching unit 105 may be implemented as the measuring unit 110, and the request resource calculating unit 107 and the network path are provided. The determiner 109 may be implemented as the controller 130. The measurement unit 110 measures the user side service quality for the current transmission path, and determines whether the measured user side service quality satisfies the required service quality. If the user side service quality measured by the measurement unit 110 does not satisfy the required service quality, the controller 110 determines another accessible transmission path as a new communication path according to a predetermined criterion, and the current transmission path. Controls to change the communication path to the determined other transmission path.

In the embodiment of the present invention, the determination of the transmission path will be described by dividing into a single transmission path and multiple transmission paths.

In addition, in the embodiment of the present invention to be described below, the determination of the transmission path will be described an embodiment of determining an access network and a transmission path having a minimum amount of required radio resources, but the determination of the transmission path is required radio for each transmission path. In addition to resources, this may be performed in consideration of service quality, service cost, and user preference.

In FIG. 1, the quality of service measuring unit 101 periodically or aperiodically measures user-side quality of service for a current transmission path and other connectable transmission paths. In this case, the current transmission path may be performed through direct measurement, and the other transmission path may be estimated by using the maximum available user side service quality value using the available radio resource. When the measurement result of the user side service quality does not satisfy the required service quality, information indicating this is transmitted to the request resource calculation unit 107. To this end, the service quality measuring unit 101 receives the required quality information for each service from the service quality management unit 103, and the user side service quality measured periodically or aperiodically about the current transmission path satisfies the required quality for each service. If not, information (or a control signal) for triggering a transmission path determination algorithm of the present invention to be described later is determined to determine another transmission path as a communication path to the request resource calculation unit 107. In this case, whether the service quality is satisfied is determined by comparing a measured value of user-side service quality with a predetermined value of the required quality for each service, or the satisfaction / dissatisfaction information of the service quality input by the user receiving the service through the user terminal. Various modifications that consider the service quality of the user side, such as making a judgment using the same, may be possible.

In addition, if a transmission path that satisfies the quality of service required for the current transmission path is found, but is capable of providing better quality of service (for example, another transmission path having a certain quality or more than the current transmission path is found). In this case, the trigger information may be transmitted to the request resource calculator 107. In this case, since it is caused by dissatisfaction of the relative service quality, in the broad sense, the satisfaction of the service quality can be extended to determining the dissatisfaction of the relative service quality.

In addition, hysteresis may be set when determining whether the quality of service for the current transmission path is satisfied, thereby preventing frequent transmission path determination from occurring near the required quality of service.

A detailed description of the transmission path determination algorithm proposed by the present invention will be described later. The information for triggering the transmission path determination algorithm (hereinafter, "trigger information") may be, for example, information about a service quality dissatisfaction of a transmission path for which a current service is provided, a cause of service quality dissatisfaction, a request resource calculation unit 107 ) May include at least one of control signals transmitted from the quality of service measuring unit 101 to the requesting resource calculating unit 107 to calculate the amount of required radio resources for another transmission path.

In addition, the service quality measuring unit 101 receives the terminal packet loss generated after combining service flows transmitted through a single or multiple transmission paths and information of a codec and a terminal used by the user terminal for service access as application layer information. Through the TCP (Transmission Control Protocol) header of the packet, time stamp information and sequence number information of the packet transmitted through the multiple transmission paths are provided as transport layer information, and the lower layer is used to measure the end quality of service. It is available. In addition, the service quality measuring unit 101 may receive time stamp information and sequence number information from a higher real time protocol (RTP) through a user datagram protocol (UDP) and use the service quality measurement. In addition, the quality of service measuring unit may receive radio resource information of another path connectable from the network search unit 105 to be used for end service quality measurement.

That is, in the embodiment of the present invention, the service quality measuring unit 101 may determine whether the service quality is satisfied by using not only the user side service quality measured in the upper layer but also the end service quality measured in the lower layer. .

The service quality measuring unit 101 receives the application layer information and the transport layer information, and in the case of a voice service, for example, a user side service quality in an upper layer such as the R value illustrated in Table 1, and If it is determined that the current quality of service does not satisfy the required quality of service index by calculating the end quality of service at lower layers such as end unidirectional transmission delay, end packet loss probability, and end throughput, the trigger information is sent to the requesting resource calculator ( 107). In addition, when the connectable transmission path is found, the radio resource information that can be provided is obtained from the connectable transmission path, and the maximum value of the user side service quality is calculated using the application layer information and the information provided by the network search unit.

In FIG. 1, the service quality management unit 103 provides service quality related information such as various service quality indicators required for each service and cost weight information for each service through a user interface such as a key input unit (not shown) (hereinafter, "required quality for each service"). Information ") to receive and store and manage. The request quality information for each service may be transmitted from the service quality management unit 103 and / or the request from the service quality management unit 103 when a request for transmission path determination is made from the service quality measurement unit 101 or the required resource calculation unit 107. The resource calculation unit 107 is provided.

In FIG. 1, the network searching unit 105 periodically transmits network discovery information obtained by searching for at least one access network in an area where a user terminal is located for each available access technology to the service quality measuring unit 101, and transmits a transmission path. The decision is transferred to the request resource calculation unit 107. The network discovery information may be searched periodically or aperiodically and transmitted to the service quality measuring unit 101 and the required resource calculating unit 107. The network discovery information may be obtained by access network information obtained through network discovery and received signal strength for each access network or transmission path obtained by measuring received signal strength for each access network or transmission path, and available modulation method for each access network or transmission path. And coding scheme information, etc. The network discovery information may be stored and managed in the network discovery unit 105.

In addition, request quality information for each service provided from the service quality management unit 103 to the request resource calculation unit 107 and the network search information provided from the network search unit 105 to the request resource calculation unit 107 are serviced. It is provided according to a request of the request resource calculation unit 107 which has received the trigger information from the quality measuring unit 101 or transferred to the request resource calculation unit 107 periodically or aperiodically without a request of the request resource calculation unit 107. Can be.

In FIG. 1, when the request resource calculation unit 107 receives the trigger information indicating the service quality dissatisfaction of the current transmission path from the service quality measurement unit 101, the request quality information for each service transmitted from the service quality management unit 103 is provided. And calculating the amount of required radio resources for each single transmission path using information obtained through network search from the network search unit 105 (hereinafter, referred to as "network search information"), or multiplexing multiple access paths that can be accessed. A path combination is generated, the amount of required radio resources is calculated for each of the multiple transmission paths included in the combination, and the required radio resource information including the calculation result is transmitted to the network path determination unit 109.

In FIG. 1, the network path determiner 109 determines a transmission path having a minimum required radio resource based on the request radio resource information for each transmission path transmitted from the request resource calculator 107. Determination of the access network may also be performed in a manner to determine the access network with the minimum required radio resource. Here, the determination of the transmission path is divided into the determination of the single transmission path and the determination of the multiple transmission path, and the determination of the multiple transmission path does not satisfy the quality of service required for the transmission path with the minimum required radio resource as a result of the determination of the single transmission path. If not, it can be performed selectively. In another embodiment, it may be possible to directly perform the determination of multiple transmission paths without performing the determination of a single transmission path.

In addition, although not shown in another embodiment, the network path determination unit 109 receives request quality information for each service from the service quality management unit 103 when determining an access network and a transmission path, and requests quality and user preference for each service. The access network and the transmission path may be determined in consideration of the like.

Therefore, in the present invention, when the current transmission path does not satisfy the user side quality of service, the network path determining unit 109 determines another transmission path according to a predetermined criterion, and the predetermined criterion is required for each radio path and for each radio service. At least one of the required quality and the user preference may be considered.

Hereinafter, an embodiment of the present invention will be described assuming an example of using a request radio resource for each transmission path based on the predetermined criteria.

In addition, the access network and the transmission path determined when considering the service quality and user preference in determining the access network and the transmission path are not necessarily the minimum amount of radio resources required when compared with other access networks and the transmission path. will be.

For example, if a user wants to be provided with a high quality service or the quality of service required for the service is high, the transmission path determined may have a relatively large amount of required radio resources compared to other transmission paths.

FIG. 2 is a block diagram functionally showing the configuration of the request resource calculator 107 in FIG.

In the request resource calculation unit 107 of FIG. 2, the trigger information L1 is transmitted from the service quality measurement unit 101 of FIG. 1, and the request quality information for each service L2 delivered from the service quality management unit 103 of FIG. 1. And the network discovery information transmitted from the network discovery unit 105 to calculate the required radio resource for each transmission path. The network discovery information includes received signal strength N1 measured for each access network or transmission path, and modulation and coding scheme information N2 available for each access network or transmission path.

In an embodiment of the present invention to be described below, it is assumed that the calculation of the required radio resource uses two pieces of information of request quality information and network discovery information for each service, but it is also possible to calculate the required radio resource using one of the two pieces of information. .

Referring to FIG. 2, the required resource calculator 107 includes an equivalent transmission rate calculator 1071, a spectral efficiency calculator 1073, and a path-specific resource calculator 1075.

In FIG. 2, the equivalent transmission rate calculator 1071 calculates an equivalent transmission rate for each transmission path for calculating a required radio resource using the trigger information L1 and the required quality information for each service L2. The spectral efficiency calculator 1073 calculates spectral efficiency for each transmission path for calculating a required radio resource using the received signal strength N1 and modulation and coding scheme information N2. The resource calculation unit 1075 for each path calculates a required radio resource for each transmission path by using the calculation result of the equivalent transmission speed for each transmission path and spectrum efficiency for each transmission path.

Hereinafter, a method of calculating an equivalent transmission rate as a factor for calculating a required radio resource for each transmission path in the embodiment of the present invention will be described in detail.

The equivalent transmission rate is calculated by integrally applying the required quality indicators for each service provided through the required quality information (L2) for each service. In the present invention, the maximum data rate and average data rate are calculated. The quality of service indicators such as delay bound, packet loss bound, and maximum burst size are calculated by applying Equation 1 below.

는 상기 지연 한계를 만족시키기 위하여 요구되는 전송 속도이며, s_i는 하나의 서비스 패킷을 성공적으로 전송하기 위한 평균 전송 횟수이며, L_i는 패킷 손실 한계 요구 사항을 의미한다. 상기 지연 한계를 만족시키기 위한 요구 전송 속도(

)를 도출하기 위한 과정은 하기 도 3, 도 4을 참조하여 설명하기로 한다. s_i는 전송 경로별 수신 신호 세기 및 접속망별로 이용 가능한 변조 및 코딩 방식에 따른 BER(Bit Error Rate)과 PER(Packet Error Rate)에 의해 아래 <수학식 2>와 같이 계산된다. In Equation 1, EB _i denotes an equivalent transmission rate for transmission path i.

Is a transmission rate required to satisfy the delay limit, s _i is an average number of transmissions for successfully transmitting one service packet, and L _i is a packet loss limit requirement. Required transmission rate to satisfy the delay limit (

) Will be described with reference to FIGS. 3 and 4. s _i is calculated according to Equation 2 below by BER (Bit Error Rate) and PER (Packet Error Rate) according to the received signal strength of each transmission path and the modulation and coding scheme available for each access network.

In Equation 2, P _{e and i} are packet error rates of the transmission path i, and l is the maximum number of transmissions.

)를 도출하는 방식을 설명하기 위한 도면이다.3 illustrates a request rate for satisfying a delay limit used in calculating an equivalent rate according to an embodiment of the present invention.

It is a figure for demonstrating the method of deriving.

)와 동일하다.Referring to FIG. 3, the service traffic 311 generated by the user terminal 310 is transmitted to the dynamic queue management block 313, and the MAC transmission is performed in the dynamic queue management block 313 at the maximum transmission rate among request quality of each service. Delivered to queue 315. The service traffic delivered to the MAC layer transmission queue 315 is transmitted according to a previously reserved radio resource or is allocated a channel access opportunity through the channel access control protocol 331 of the base station 330 to receive a packet through a wireless channel. Send it. Traffic generated by an external server (not shown) and transmitted on the downlink is transmitted to the base station 330 at the maximum transmission rate in a dynamic queue management block of an edge router (not shown), and the base station 330 After storing the service traffic in the MAC layer transmission queue, and transmits the service traffic to the user terminal 310 by using the radio resources allocated for the service. In this case, it is assumed that no packet error occurs on the wireless channel. 4 is a diagram illustrating a dual token bucket model for deriving a required transmission rate for satisfying a delay limit according to an embodiment of the present invention. As shown in FIG. 3, a system having a multi-layer queue in a wireless communication system may be modeled using a double token bucket model. At this time, the transmission rate of the traffic passing through the double token bucket is required transmission rate (

Same as).

)는 아래 <수학식 3>과 같이 나타낼 수 있다.First, the maximum burst size of user traffic (

) Can be expressed as in Equation 3 below.

In Equation 3, R _peak denotes a maximum transmission rate of user traffic, and t denotes a time at which user traffic occurs at the maximum transmission rate.

In FIG. 4, the size B _i of the bucket refers to a radio resource that is additionally reserved in order to remove a delay of user traffic generated at the maximum transmission rate in the base station 310 or the user terminal 330. Is calculated as

In this case, R _mean means an average transmission rate. Equation 4 is summarized as in Equation 5 below when the time t of user traffic occurs.

)는 최대 버스트 크기로 저장된 사용자 트래픽을 지연 한계 이내에서 전송하기 위하여 요구되는 전송 속도로 아래 <수학식 6>와 같이 나타낼 수 있다. Required baud rate to satisfy the delay limit

) Is a transmission rate required to transmit user traffic stored in the maximum burst size within a delay limit, as shown in Equation 6 below.

)의 일반식을 구할 수 있다. In Equation 6, D denotes a request delay limit of a service. After removing t from Equation 6 and arranging, the required transmission rate (

) Can be obtained.

)는 최대 전송 속도와 동일한 값으로 도출되며, 가변 비트율(VBR : Variable Bit Rate)의 음성 서비스의 경우 무음 구간에는 낮은 전송 속도로 트래픽을 발생시키나 주기적으로 발생하므로 유음 구간의 비율과 무음 구간의 비율에 따라 평균 전송 속도가 계산된다. 따라서 음성 서비스에서 요구 전송 속도(

)는 아래 <수학식 8>과 같이 도출할 수 있다.Service quality indicators required may vary depending on the type of service. For example, a fixed bit rate (CBR) voice service has the same maximum transmission rate and average transmission rate, so the required transmission rate (

) Is derived at the same value as the maximum transmission rate.In the case of a variable bit rate (VBR) voice service, traffic is generated at a low transmission rate in the silent period, but occurs periodically, so that the ratio of the silent period and the ratio of the silent period According to the average transmission rate is calculated. Therefore, the voice rate required by the voice service (

) Can be derived as in Equation 8 below.

와

는 각각 유음구간의 비율과 무음 구간의 비율을 의미한다. 실시간 스트리밍 서비스의 경우 지연 한계, 평균 전송 속도, 최대 전송 속도, 사용자 트래픽의 최대 버스트 크기와 같은 서비스 품질 지표를 요구하므로 실시간 스트리밍 서비스에서 요구 전송 속도(

)는 상기 <수학식 7>과 같이 도출된다.In Equation 8 above

Wow

Denotes the ratio of the sound section and the silent section, respectively. The live streaming service requires quality of service metrics such as delay limit, average transfer rate, maximum transfer rate, and maximum burst size of user traffic.

) Is derived as shown in Equation 7 above.

According to an embodiment of the present invention, the required radio resource is represented by the following Equation 9 by using the equivalent transmission rate calculated as shown in Equation 1 using the required quality indicator for each service and the spectral efficiency according to the received signal strength. Calculated together, the calculated required radio resource is used for access network or transmission path determination.

는 전송 경로별로 측정된 수신신호의 세기에 따른 이용 가능한 변조 방식 및 코딩 방식에 따라 단위 대역폭당 전송 가능한 전송 가능한 비트수를 의미하고,

는 상기 등가 전송 속도를 제공하기 위하여 요구되는 단위 시간당 대역폭을 의미한다. The spectral efficiency in Equation (9)

Denotes the number of transmittable bits per unit bandwidth according to the available modulation scheme and coding scheme according to the strength of the received signal measured for each transmission path,

Means bandwidth per unit time required to provide the equivalent transmission rate.

In addition, according to the embodiment of the present invention, the required radio resources for the individual transmission paths are calculated according to Equation 9, and the required radio resources for the multipath transmission are simultaneously calculated. At this time, if the required radio resource of the multipath transmission is smaller than the required radio resource for the single transmission path or the currently available radio resource is smaller than the required radio resource for the single transmission path, the multipath is not satisfied. By calculating the required radio resources of the can determine the multiple transmission paths with the minimum required radio resources.

The procedure for calculating the required radio resource for multiple transmission paths is the same as the procedure for calculating the required radio resource in a single transmission path except for calculating the equivalent transmission rate. In multiple transmission paths, the equivalent transmission rate is calculated in different ways depending on the transmission method. In an embodiment of the present invention, a transmission scheme is divided into a diversity mode and a multiplexing mode in a multiple transmission path. Hereinafter, a method of calculating an equivalent transmission rate according to each transmission method will be described in detail.

First, in the diversity mode, since the same packet is repeatedly received through at least two transmission paths, the packet error probability is reduced because packet errors occur only when all packets are lost in the at least two transmission paths. Therefore, since the number of retransmissions required in the diversity mode decreases, the equivalent transmission rate is calculated by applying the reduced packet error rate as shown in Equation 10 below instead of the packet error rate described in Equation 2 above. do.

Equation 10 shows the packet error rate p _e in the multiple transmission paths when the number of transmission paths is assumed to be two. Wherein P _{e, path1} is a packet error rate, P _{e, path2} of the transmission path 1 means the packet error rate of the transmission path 2. If the number of transmission paths is increased, the packet error rate p _e may be obtained in the multiple transmission paths by further multiplying the packet error rate by the increased transmission path.

In the multiplexing mode, since one packet is transmitted divided into at least two transmission paths, the average transmission rate R _mean is divided into two paths as shown in Equation 11 below, assuming that the number of transmission paths is two.

In Equation 11, R _{mean and path1 mean} an average transmission rate of transmission path 1 and R _{mean and path2 mean} an average transmission speed of transmission path 2.

In the diversity mode, the equivalent transmission rate is calculated by applying the average transmission rate as shown in Equation 11 as the average transmission rate R _mean in Equation 4.

Referring to Equation 4, the average transmission rate is related to a radio resource allocated to remove delays of user traffic, and in Equation 11, the average transmission rate is allocated for each transmission path. The standard allocates radio resources according to the criteria shown in Equation 12 below, taking into account criteria such as spectrum efficiency, service cost, and available radio resources for each transmission path.

Definitions of the parameters used in Equation 12 are shown in Table 3 below.

When transmitting user traffic in the multiplexing mode, a user prefers a low access rate according to the user's preference, and a radio resource is preferentially allocated to a transmission path having a low access rate, and a user prefers a high bandwidth. Regardless of whether a radio resource is allocated to a transmission path having a high bandwidth, radio resources are preferentially allocated. Therefore, the equivalent transmission rate can be calculated and the transmission path can be determined according to the user's preference such as service quality / service cost desired by the user.

The equivalent transmission rate in the multiple transmission paths is calculated by applying the equivalent transmission rate allocated for each transmission path, and the required radio resource is derived as the sum of the required radio resources calculated in the individual transmission paths.

Hereinafter, a transmission path determining method according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1, 5, and 6. The method of FIGS. 5 and 6 is performed at a user terminal with the apparatus of FIG. 1.

5 is a flowchart illustrating a method of determining a single transmission path according to an embodiment of the present invention.

Referring to FIG. 5, in step 501, the service quality management unit 103 receives and stores request quality information for each service such as various service quality indicators required for each service and cost weight information for each service through a user interface such as a key input unit. . In another embodiment, the request quality information for each service may be received and stored by a user terminal through a corresponding access network. In addition, it is also possible to obtain required quality information for each service through signaling between the user terminal and the access network. In operation 503, the network search unit 105 stores network discovery information obtained by searching for at least one access network for each available access technology (RAT). The network discovery information includes received signal strength information for each radio access technology and information on a modulation scheme and a coding scheme that can be provided.

Thereafter, in step 505, the service quality measuring unit 101 periodically or aperiodically measures user-side service quality with respect to a transmission path currently provided by the service, and the result of measuring the user-side service quality does not satisfy the required service quality. If not, in step 507, the trigger information for commanding the determination of another transmission path is transmitted to the request resource calculation unit 107.

In this case, it is also possible to determine whether the required service quality is satisfied by considering the end service quality in the lower layer together with the user side service quality in the upper layer. In this case, whether or not the service quality is satisfied, if at least one of the user side service quality and the end service quality does not satisfy the required service quality, the transmission path may be determined by determining that the service quality is not satisfied. For example, in the lower layer, if the end service quality satisfies the required quality of service but the user side service quality does not satisfy the required quality of service, the transmission path is determined again according to an embodiment of the present invention. The required resource calculation unit 107 calculates an equivalent transmission rate for each available transmission path according to the service flow by using the request quality information for each service transmitted from the service quality management unit 103, and in step 511, the network search unit 105. The spectral efficiency for each transmission path is calculated using the network discovery information transmitted from

Thereafter, in step 513, the required resource calculator 107 calculates an amount of required radio resources for each transmission path by applying the equivalent transmission speed and spectral efficiency to Equation (9), and includes each transmission path including the calculation result. The network path determining unit 109 transmits the requested radio resource information to the network path determining unit 109, and the network resource determining unit 109 that has received the requested radio resource information transmits the transmission path with the minimum required radio resource in step 515. Determine. Then, the user terminal may change the access path to the transmission path determined in step 515 to receive the service.

Although not shown in FIG. 5, in another embodiment, the network path determining unit 109 receives request quality information for each service from the service quality management unit 103 when determining a transmission path, and considers the request quality for each service and user preference. To determine the transmission path. In this case, the determined transmission path may not have a minimum amount of required radio resources.

6 is a flowchart illustrating a method of determining multiple transmission paths according to an embodiment of the present invention.

The above-described transmission path determining method of FIG. 5 is performed when a single transmission path is determined, and when the determined single transmission path also does not satisfy the required service quality as a result of the measurement of the service quality measuring unit 101, the user terminal transmits the transmission path of FIG. Multiple transmission paths may be determined according to a determination method to provide a service that satisfies a required quality of service.

Referring to FIG. 6, when it is determined in step 601 that the required resource calculation unit 107 does not satisfy a required quality of service, the resource calculation unit 107 generates a multipath combination for a plurality of accessible transmission paths, and in step 603. Calculates the required radio resource amount of the multiple transmission combinations included in the multiple transmission path combination. At this time, the total required radio resource for each multi-path is calculated by calculating the equivalent transmission rate in different ways according to the transmission method of the multi-transmission path as described above. Thereafter, in step 605, a radio resource required for each path of the multipath combination is calculated. If operating in the diversity mode, the required radio resource for each path is calculated equally. However, when operating in the multiplexing mode, radio resources are allocated in consideration of criteria such as spectrum efficiency, service cost, and available radio resources for each transmission path. That is, in the multiplexing mode as described above, since the required radio resources may be different for each transmission path constituting the multiple transmission paths, it is necessary to recalculate the required radio resources for each transmission path constituting the multiple transmission paths in step 605.

In an embodiment of the present invention, a transmission scheme of the multiple transmission paths is divided into a diversity mode and a multiplexing mode, and the transmission scheme is one of the causes of dissatisfaction with service types such as voice service and streaming service, user preference, and service quality. It may be determined in consideration of at least one.

Thereafter, in step 607, the required resource calculator 107 determines a multiple transmission path having the minimum required radio resource, and in step 609, the service quality measuring unit 101 measures whether the determined multiple transmission path satisfies the required quality of service. In this case, the user terminal may terminate the determination of the multi-transmission path and receive an improved quality of service through the determined multi-transmission path. On the other hand, if the quality of service required in step 609 is not satisfied, the service quality measuring unit 101 decreases the required service quality step by step, and repeats the operations after step 601 to satisfy the service quality. Will be determined.

Claims (43)

In the method of determining the transmission path in a wireless communication system,
Acquiring user side service quality that can be provided for each path; And
And determining at least one transmission path according to a predetermined criterion based on user side quality of service.
The method of claim 1,
In determining the transmission path,
The user terminal determines the transmission path characterized in that the transmission path.
The method of claim 1,
In obtaining the user side service quality that can be provided for each path,
Measuring the quality of service on the user side of the current connection path,
And estimating the user side service quality of at least one connectable path.
The method of claim 3, wherein
In estimating user side quality of service of the at least one connectable path,
And using radio resource information provided in the at least one connectable path.
The method of claim 3, wherein
In estimating the user side quality of service of the at least one connectable path,
And estimating a maximum value of user-side service quality which can be provided according to radio resources that can be provided in the at least one connectable path.
The method of claim 1,
The user-side service quality measures at least one factor affecting sensory satisfaction and mental satisfaction.
The method of claim 1,
And the user side quality of service further uses at least one information provided from an application layer and a transport layer.
The method of claim 1,
The user side quality of service further comprises at least one indicator of available network resources, end transmission delay, end transmission rate, end packet loss probability, and end throughput.
The method of claim 1,
The user side quality of service includes R value, Mean Opinion Score (MOS), Perceptual Speech Quality Measure (PSQM), Perceptual Evaluation of Speech Quality (PESQ), Video Quality Measurement (VQM), page response time, PSNR (Peak Signal to Noise Ratio), characterized in that at least one of the transmission path determining method.
The method of claim 1,
The predetermined criterion includes at least one of required radio resources, service costs, and user preferences for each transmission path.
The method of claim 10,
The user preference is a transmission path determining method, characterized in that the weight value used to combine the elements that make up the predetermined criteria.
The method of claim 1,
In determining the transmission path,
And determining the at least one transmission path when another transmission path whose current transmission path satisfies the required quality of service but whose predetermined criterion is higher than the current transmission path is higher than the current transmission path is found.
The method of claim 12,
In determining the at least one transmission path,
And determining the current transmission path when the searched other transmission paths are lower than the predetermined reference by more than a predetermined value than the current transmission path.
The method of claim 1,
The determining process,
Determining a single transmission path with at least one transmission path; And
And selecting multiple transmission paths when a single transmission path does not satisfy the required quality of service.
The method of claim 14,
In selecting the multiple transmission paths,
And determining the multiple transmission path including the current transmission path.
The method of claim 14,
In selecting the multiple transmission paths,
A method for determining a transmission path using at least one of a request radio resource for each path, a path selection preference for each service, a service cost, and a user preference.
17. The method of claim 16,
The path preference for each service may include at least one of service type, user preference, end-to-end transmission delay satisfaction, end-to-end speed satisfaction, end-to-end packet loss satisfaction, and end-to-end throughput satisfaction.
The method according to claim 4 or 10,
The request radio resource for each transmission path is calculated using at least one of request quality information for each service and network discovery information.
The method of claim 18,
In using the required quality information for each service,
A transmission path determining method using an equivalent transmission rate for each transmission path calculated by considering at least one of an average transmission rate, a maximum burst size, a transmission delay limit of traffic, and a packet loss probability.
The method of claim 17,
In using the network search information,
And using the spectral efficiency for each path calculated based on at least one of the received signal strength measured for each path, the estimated packet loss probability according to the modulation and coding scheme information available for each transmission path.
A communication device for determining a transmission path of a service in a wireless communication network,
A measuring unit which obtains user side service quality that can be provided for each path; And
And a control unit for selecting at least one transmission path that satisfies a user side service quality required by a user according to a predetermined criterion.
The method of claim 21,
And a measurement unit for measuring and determining the user side service quality and a control unit for selecting another transmission path accessible according to the predetermined criterion.
The method of claim 21.
The measuring unit for obtaining the user side quality of service determines a transmission path including at least one of a service quality measuring unit for measuring the user side service quality, whether the user side service quality is satisfied, network search unit for measuring the search information for each path Communication device.
The method of claim 23,
And the measuring unit measures the user side service quality using a service quality that can be recognized by a user.
The method of claim 24,
The measurement unit R value, MOS (Mean Opinion Score), PSQM (Perceptual Speech Quality Measure), PESQ (Perceptual Evaluation of Speech Quality), VQM (Video Quality Measurement), page response time (page response time), PSNR (Peak Signal) and a transmission path determining communication device for measuring the quality of service of the user side by using at least one indicator.
The method of claim 23,
And the measurement unit additionally uses at least one information provided from an application layer and a transport layer to measure the user side service quality.
The method of claim 23,
And the measuring unit measures the user side service quality by additionally using at least one indicator of available network resources, end transmission delay, end transmission speed, end packet loss probability, and end throughput.
The method of claim 21,
And the control unit for selecting the transmission path includes at least one of a request resource calculator for calculating a request resource for each path and a network path determiner according to a predetermined criterion.
29. The method of claim 28,
The predetermined criterion includes at least one of required radio resources for each transmission path, required quality for each service, service cost, and user preference.
29. The method of claim 28,
The controller is further configured to determine the other transmission path when the current transmission path satisfies the required quality of service, but the other transmission path having a criterion greater than or equal to the current transmission path is found. Device.
29. The method of claim 28,
And the control unit is further configured to determine a multiple transmission path to the other transmission path.
The method of claim 31, wherein
The other transmission path further comprises the multiple transmission path using a transmission method determined according to the transmission method determination criteria.
33. The method of claim 32,
The transmission method determination criterion determines the transmission method of the multiple transmission path in consideration of at least one of the cause of the service type, the user preference, the service quality unsatisfactory.
The method of claim 33, wherein
And the transmission scheme is one of diversity transmission and multiplexed transmission.
29. The method of claim 28,
And the control unit is further configured to determine, as the other transmission path, a transmission path having the least amount of the required radio resources among the plurality of transmission paths.
36. The method of claim 35 wherein
And the control unit calculates a request radio resource for each transmission path using at least one of request quality information for each service and network discovery information.
The method of claim 36,
And calculating the equivalent transmission rate for each transmission path by using the required quality information for each service.
39. The method of claim 37,
And the control unit calculates the equivalent transmission rate using a dual token bucket model.
39. The method of claim 37,
And the control unit is further configured to calculate the equivalent transmission rate in consideration of the transmission scheme of the multiple transmission paths when another transmission path is the multiple transmission paths.
39. The method of claim 37,
And the control unit calculates the equivalent transmission rate in consideration of at least one of an average transmission rate, an average transmission rate, a maximum burst size, a transmission delay limit of traffic, and a packet loss probability.
The method of claim 36,
And the control unit is further configured to calculate the spectral efficiency for each transmission path using the network discovery information.
42. The method of claim 41 wherein
The spectral efficiency for each path includes at least one of a received signal strength measured for each transmission path, an expected packet loss probability according to modulation and coding scheme information available for each transmission path.
43. The method of claim 42,
In considering the expected packet loss probability,
A transmission path determination communication apparatus, characterized by considering multiple transmission paths and transmission schemes.

Images