KR20200107717A - Apparatus and method for transmitting and receiving data in a wireless communication system - Google Patents

Abstract

The present invention relates to a method for transmitting and receiving data in a wireless communication system and an apparatus thereof. According to the present invention, an operation method of a terminal in a wireless communication system may comprise the steps of: identifying an omission of at least one data packet among a plurality of data packets transmitted from another terminal; determining an event which caused the at least one data packet to be omitted; and setting a length of a timer for receiving the at least one omitted data packet based on a network metric corresponding to the determined event.

Description

Device and method for transmitting and receiving data in a wireless communication system {APPARATUS AND METHOD FOR TRANSMITTING AND RECEIVING DATA IN A WIRELESS COMMUNICATION SYSTEM}

The present disclosure relates generally to transmitting and receiving data in a wireless communication system, and more particularly, to an apparatus and method for optimizing transmission of data packets in a wireless Transmission Control Protocol (TCP) communication system.

In recent years, due to the rapid development of computer technology and computer networks, wireless communication has become very important. In general, the most reliable protocol in a computer network is recognized as a Transmission Control Protocol/Internet Protocol (TCP/IP) protocol. However, the TCP/IP protocol is a protocol that works well in a wired network where network nodes are fixed. Therefore, to the side of a variety of network metric (metrics), including the 5th generation (5 ^th generation, 5G) As the network is introduced, the throughput (throughput), reliability (reliability), the standby time (latency), facilitate the wireless TCP There is a demand for it to work.

Based on the above discussion, the present disclosure may provide an apparatus and method for transmitting and receiving data in a wireless communication system.

In addition, an embodiment of the present disclosure may provide an apparatus and method for identifying a missing of at least one data packet among a plurality of data packets transmitted from a transmitting end.

In addition, an embodiment of the present disclosure may provide an apparatus and method for determining an event that caused a data packet to be dropped.

In addition, an embodiment of the present disclosure may provide an apparatus and method for setting a length of a timer for receiving a missing packet based on a network metric corresponding to an event.

According to an embodiment of the present disclosure, a method for optimizing transmission of data packets in a wireless TCP communication system includes at least one of a plurality of data packets transmitted by a Transmission Control Protocol (TCP) user device. Receiving the data packet and identifying a missing of one or more of the received data packets based on the occurrence of one or more events; Starting the RTO timer during a time interval waiting to receive one or more missing data packets until expiration of the retransmission timeout (RTO) timer; In this case, network metrics may be calculated based on a current network state in which a plurality of data packets are transmitted, and modified based on a network metric calculated to receive one or more missing data packets. It may include generating an RTO timer.

The method according to an embodiment of the present disclosure, one or more events may include at least one of spurious loss (Spurious Loss, SL), burst loss (Burst Loss, BL), and continuous packet loss (Consecutive Packet Loss, CPL). have.

In the method according to an embodiment of the present disclosure, when an SL occurs, one or more data packets that are missing may be recovered by estimating an RTO based on a network metric.

A method according to an embodiment of the present disclosure includes the steps of providing an edge node based on current network conditions, in the case of BL occurrence, the missing one or more packets; Determining a dynamic RTO based on the mobility parameter; It may be recovered by recovering one or more missing data packets based on the adjusted Snoop and ARQ retransmissions.

The method according to an embodiment of the present disclosure may further include recovering one or more missing data packets from the end server after expiration of the dynamic RTO.

According to an embodiment of the present disclosure, when CPL occurs, one or more missing data packets may be recovered by managing a transmission rate of a Dup (duplicate) ACK (acknowledgement), and the step of managing the Dup ACK includes: Determining the occurrence of an event; Calculating a handover time when determining a handover event; It may include the step of determining the number of TDA (Triple Dup ACK) to be transmitted based on the congestion window learned in the server, the calculated TDA is shared before the expiration of the RTO, the number of TDAs to be transmitted based on the handover time It may include performing at least one of adjustment or control of.

According to an embodiment of the present disclosure, when CPL occurs, one or more missing data packets signal the occurrence of a CPL event to a server, wherein the server stops data transmission upon receiving the signal; Setting a probe time period and a sequence number for one or more probe data packets, wherein the probe time period is indicated to a server; Removing one or more data packets transmitted by the server until expiration of the probe time period; Transmitting a success probe ACK to the server until expiration of the probe time period; Upon receiving the retransmitted one or more missing data packets from the server, the server may be recovered by retransmitting the one or more missing data packets after receiving the success probe ACK.

According to an embodiment of the present disclosure, the occurrence of one or more events may include controlling unnecessary retransmission of data packets and delayed timeout in order to optimize the transmission of data packets in a TCP communication system.

According to an embodiment of the present disclosure, a user equipment (UE) for optimizing transmission of data packets in a wireless TCP communication system includes a processor and a memory communicatively coupled with the processor, wherein the memory is a processor Stores executable instructions and, upon execution, causes the user equipment to receive at least one data packet from among a plurality of data packets transmitted by the TCP user device, and receive based on the occurrence of one or more events RTO timer during the time interval in which one or more data packets are missing from among the dropped data packets and waits to receive one or more missing data packets until expiration of the retransmission timeout (RTO) timer The network metric may be calculated based on the current network state in which the plurality of data packets are transmitted, and a modified RTO timer may be generated based on the calculated network metric to receive one or more missing data packets. .

According to an embodiment of the present disclosure, a method of operating a terminal in a wireless communication system includes: identifying an omission of at least one data packet among a plurality of data packets transmitted from another terminal; Determining an event that caused the at least one data packet to be dropped; And setting a length of a timer for receiving the at least one missing data packet based on a network metric corresponding to the determined event.

According to an embodiment of the present disclosure, in a wireless communication system, a terminal includes an input/output interface; A memory for storing one or more instructions; And at least one processor that executes the one or more instructions stored in the memory, wherein the at least one processor identifies the omission of at least one data packet among a plurality of data packets transmitted from another terminal, and the An event that caused at least one data packet to be dropped may be determined, and a length of a timer for receiving the at least one missing data packet may be set based on a network metric corresponding to the determined event.

According to an embodiment of the present disclosure, a computer-readable recording medium includes: identifying an omission of at least one data packet among a plurality of data packets transmitted from another terminal; Determining an event that caused the at least one data packet to be dropped; And a program for setting a length of a timer for receiving the at least one missing data packet based on a network metric corresponding to the determined event.

1A is an exemplary system diagram for optimizing transmission of data packets in a wireless Transmission Control Protocol (TCP) communication system according to an embodiment of the present disclosure.
1B illustrates an example in which a user device experiences various losses during transmission of data packets in a wireless network according to an embodiment of the present disclosure.
2 is a flowchart illustrating a method of operating a user equipment (UE) according to an embodiment of the present disclosure.
3 is a block diagram of user equipment according to an embodiment of the present disclosure.
4 shows an example of a wireless filter according to an embodiment of the present disclosure.
5 is an exemplary flow chart in which a retransmission timeout (RTO) filter operates according to an embodiment of the present disclosure.
6 is an exemplary diagram related to a spurious loss (SL) according to an embodiment of the present disclosure.
7 is an exemplary sequence diagram for recovering lost data packets when a burst loss (BL) occurs according to an embodiment of the present disclosure.
8 illustrates an example for recovering missing data packets when a continuous packet loss (CPL) occurs using a filter method according to an embodiment of the present disclosure.
9 is an exemplary sequence diagram for recovering missing data packets when CPL occurs, using a probe method according to an embodiment of the present disclosure.
10 is an exemplary flowchart for recovering missing data packets when CPL occurs, using a probe method according to an embodiment of the present disclosure.
11 is a performance graph related to RTO setting when BL occurs according to an embodiment of the present disclosure.
12 is a performance graph related to RTO setting when CPL occurs according to an embodiment of the present disclosure.
13 is a flowchart illustrating a method of operating user equipment according to an embodiment of the present disclosure.
14 is a detailed block diagram of user equipment according to an embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts not related to the description are omitted in order to clearly describe the present disclosure, and similar reference numerals are attached to similar parts throughout the specification.

The terms used in the present disclosure have been described as general terms currently used in consideration of the functions mentioned in the present disclosure, but this may mean various other terms depending on the intention or precedent of a technician working in the field, the emergence of new technologies, etc. I can. Therefore, terms used in the present disclosure should not be interpreted only by the name of the term, but should be interpreted based on the meaning of the term and the contents throughout the present disclosure.

In addition, terms such as first and second may be used to describe various components, but the components should not be limited by these terms. These terms are used for the purpose of distinguishing one component from another.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element interposed therebetween. . In addition, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

Phrases such as "in one embodiment" appearing in various places in the present disclosure are not necessarily all referring to the same embodiment.

An embodiment of the present disclosure may be represented by functional block configurations and various processing steps. Some or all of these functional blocks may be implemented with various numbers of hardware and/or software components that perform specific functions. For example, the functional blocks of the present disclosure may be implemented by one or more microprocessors, or may be implemented by circuit configurations for a predetermined function. In addition, for example, the functional blocks of the present disclosure may be implemented in various programming or scripting languages. The functional blocks may be implemented as an algorithm executed on one or more processors. In addition, the present disclosure may employ conventional techniques for electronic environment setting, signal processing, and/or data processing. Terms such as "mechanism", "element", "means" and "configuration" may be used broadly, and are not limited to mechanical and physical configurations.

In addition, the connecting lines or connecting members between the components illustrated in the drawings are merely illustrative of functional connections and/or physical or circuit connections. In an actual device, connections between components may be represented by various functional connections, physical connections, or circuit connections that can be replaced or added. In addition, the same reference numerals in FIGS. 1A to 14 may represent consistent features throughout the drawings.

Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings.

In general, data loss may occur due to bit rates and handovers in wireless networks. Therefore, wireless handover may not be efficiently managed in the existing TCP system. In addition, in terms of a moving network and coordinated multi-points (CoMP), development of a system network improvement of a current wireless communication system is in progress. In addition, when the bandwidth error rate and the bandwidth delay product (BDP) increase, there may be a problem that the utilization rate in the existing system is lowered. In addition, the existing TCP system mainly uses Karn and Jacobson's algorithm, which is not accurate in wireless networks.

Embodiments of the present disclosure relate to a method and user equipment for optimizing transmission of data packets in a wireless TCP (WTCP) communication system. In one embodiment, WTCP may be a proxy-based modification of TCP that preserves the end-to-end semantics of TCP. TCP is an important standard and one of the vital elements of the Internet protocol suite, but there are various problems in data retransmission, and retransmission ambiguity is one of those various problems.

In general, one or more algorithms to resolve this retransmission ambiguity can be used in TCP. In one embodiment, one or more algorithms may include Karn and Jacobson's algorithm. These algorithms are not reliable over TCP and may not work correctly over TCP. Under such conditions, the present disclosure may identify, from the received data packets, the omission of one or more data packets based on the occurrence of one or more events.

In one embodiment, the one or more events may include triggering of at least one of spurious loss (SL) and continuous packet loss (CPL). A retransmission timeout (RTO) timer may be started during a time interval for receiving one or more missing data packets. The RTO may mean a time for a transmitter to wait for an acknowledgment for a transmitted segment.

The network metric may be calculated based on the current network conditions over which data packets are transmitted. Thereafter, based on the network metric, the RTO timer for receiving the missing one or more data packets may be modified. The method described in the present disclosure can optimize transmission of data packets in a wireless TCP communication system by controlling unnecessary retransmission of missing data packets using a modified RTO timer. The present disclosure may provide a solution for optimizing data transmission at the user equipment level, in which case the need for any modification at the base station or other network entities may be eliminated.

1A is an exemplary system diagram for optimizing transmission of data packets in a wireless TCP communication system according to an embodiment of the present disclosure.

Referring to FIG. 1A, a system 100 may include user equipment (UE) 101, user devices 103-1 to 103-N, and a communication network 105. . System 100 may include user equipment 101 connected to a user device (eg, 103-1) through a communication network 105. The user device may provide data packets to user equipment 101.

In one embodiment, the user equipment 101 may mean a terminal. That is, the terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In one embodiment, the terminal may serve as a transmitting end or a receiving end. In addition, other terminals may perform the role of a transmitting end or a receiving end.

In one embodiment, the user equipment 101 may include an input/output (I/O) interface 107, a memory 109, and a processor 111. However, not all of the components shown in FIG. 1A are essential components of the user equipment 101. The user equipment 101 may be implemented by more components than the components shown in FIG. 1A, or the user equipment 101 may be implemented by fewer components than the components shown in FIG. 1A.

In one embodiment, the input/output interface 107 may communicate with a user device or other electronic device connected to the user equipment 101 by wire or wirelessly. For example, the input/output interface 107 may receive a plurality of data packets from a user device.

Various types of data such as programs and files such as an application may be installed and stored in the memory 109. The processor 111 may access and use the data stored in the memory 109 or may store new data in the memory 109. For example, a plurality of data packets received from the input/output interface 107 may be stored in the memory 109. The memory 109 may be communicatively connected with the processor 111 of the user equipment 101. Further, the memory 109 may store processor instructions that enable the processor 111 to execute instructions for optimizing the transmission of data packets in a wireless TCP communication system.

The processor 111 controls the overall operation of the user equipment 101 and may include at least one processor such as a CPU or a GPU. Processor 111 may control other components included in user equipment 101 to perform operations to operate user equipment 101. For example, the processor 111 may execute a program stored in the memory 109, read a stored file, or store a new file. In one embodiment, the processor 111 may perform an operation for operating the user equipment 101 by executing a program stored in the memory 109.

According to an embodiment, in a wireless TCP communication network, a subject transmitting a data packet may be a transmitting node or a transmitter, receiving a data packet transmitted from the transmitting end, and transmitting an acknowledgment (ACK). The subject may be defined as a receiving node or a receiver. In Fig. 1A, the user equipment 101 may operate as a transmitting end or a receiving end. The user device can also operate as a transmitting end or a receiving end. For example, when the user device is the transmitting end and the user equipment 101 is the receiving end, the user device can transmit a data packet to the user equipment 101, and the user equipment 101 responds to the received data packet, ACK can be sent to the user device.

Although only the configuration included in the user equipment 101 is illustrated in FIG. 1A, this is for convenience of description, and the user device may also include the same configuration as the user equipment 101. For example, the user device may include an input/output interface, a memory, and a processor, but is not limited thereto.

In one embodiment, during the data transmission process, the user equipment 101 may receive at least one data packet from among a plurality of data packets transmitted by one of the user devices through the wireless TCP communication network. . User equipment 101 may receive each of a plurality of data packets transmitted by a user device. However, when receiving at least one data packet, the user equipment 101 may identify one or more missing data packets among the received data packets. In this case, data packets may be dropped due to occurrence of one or more events. User equipment 101 may identify one or more missing data packets based on the type of occurrence of one or more events.

In one embodiment, one or more events that may cause a data packet to be missed are at least one of spurious loss (SL), burst loss (BL), and continuous packet loss (CPL). May include triggering. In one embodiment, the SL may be caused by a sudden delay spike or reordering in the network, which SL may cause the TCP communication system to experience a loss event. In a TCP network, the loss can be interpreted as a sign of congestion and can cause a reduction in the transmission rate of the protocol.

In one embodiment, BL may mean that in a sequence of consecutive symbols received through a communication channel, the first symbol and the last symbol are in an error state. Further, there may not be a contiguous subsequence of correctly received symbols within an error burst. In one embodiment, CPL may mean loss of multiple consecutive packets in a handover situation. In one embodiment, handover may refer to a process of transmitting an ongoing data session from one channel to another. Embodiments of the present disclosure may be applied to ultra-low latency in a communication system.

In one embodiment, the user device may be any computing devices associated with users. For example, certain computing devices may include laptops, desktop computers, Personal Digital Assistants (PDAs), notebooks, smartphones, tablets, and any other computing devices. Can include. One of ordinary skill in the art can understand that for the provision of data packets, any other user devices not explicitly mentioned in this disclosure may be encompassed.

In one embodiment, the communication network 105 may include a wireless network using a wireless application protocol (WAP), the Internet, and Wi-Fi, but is not limited thereto. For example, the communication network 105 is a second generation (2 ^nd generation, 2G), third generation (3 ^rd generation, 3G), LTE (Long Term Evolution), and the fifth generation (5 ^th generation, 5G) wireless It may include different generations of wireless communication systems, such as communication systems. User equipment 101 and user devices may be interconnected using TCP. In this case, the user equipment 101 may optimize data transmission by controlling unnecessary retransmission and delayed timeout. Through the optimization of such data transmission, the latency of the TCP communication system can be improved. In one embodiment, user equipment 101 may include, but is not limited to, laptops, computers, PDAs, notebooks, smart phones, tablets, and any other user computing device. Although not explicitly stated, those skilled in the art can understand that any other devices may be used as user equipment 101 of the present disclosure.

1B illustrates an example in which a user device experiences various losses during transmission of data packets in a wireless network according to an embodiment of the present disclosure.

Referring to FIG. 1B, a TCP communication system 113 including one or more servers and routers connected through a first base station 115 and a second base station 119 located in an arbitrary area is illustrated. In one embodiment, a scenario in which the user 117 makes a call using a user device in an area near the first base station 115 may be considered. In one embodiment, the user device may mean a mobile phone. In the above-described scenario, the mobile phone associated with the user 117 may receive at least one packet from a receiving end through the first base station 115.

In one embodiment, a scenario in which the user 117 starts moving slowly from a static state may be considered. In this scenario, the user 117 may experience an SL event. At this time, the SL event may be poll-based, and may be initiated when any download operation occurs in the mobile phone. In addition, the SL event may occur together with the occurrence of a BL event and a CPL event described later.

In one embodiment, a scenario in which the user 117 moves from a Line of Sight (LOS) to a Non-Line of Sight (NLOS), or conversely from an NLOS to an LOS may be considered. In this scenario, the user 117 can experience a BL event. In one embodiment, when the user 117 moves from the first base station 115, so that the mobile phone of the user 117 is handed over from the first base station 115 to the second base station 119, the user 117 ) Can experience CPL events. In this case, the first base station 115 may refer to a gNode B (gNB), and the second base station 119 may refer to an eNode B (eNB). In one embodiment, the CPL event may occur in an outrage area during handover. In an embodiment, since one or more events may be independent of each other, all events may occur in combination with each other. In one embodiment, a base station, such as the first base station 115 and the second base station 119, is a subject that performs resource allocation of the terminal, gNode B, eNode B, Node B, BS (Base Station), radio access It may be at least one of a unit, a base station controller, or a node on a network.

In one embodiment, due to the occurrence of at least one of the above-described events, one or more data packets transmitted to the user equipment 101 may be omitted. User equipment 101 may identify one or more missing data packets and may initiate an RTO timer during a time interval waiting to receive the missing one or more data packets. In one embodiment, by using the RTO, TCP can guarantee data transmission even if there is no feedback from the data receiving end.

In one embodiment, the network metric may be calculated based on current network conditions over which a plurality of data packets are transmitted. Thereafter, the user equipment 101 may generate a modified RTO timer based on the calculated network metric in order to receive the missing one or more data packets. Using the modified RTO timer, the user equipment 101 can optimize the transmission of data packets in a TCP communication system.

In one embodiment, the occurrence of the at least one event described above may include controlling unnecessary retransmission of data packets and a delayed timeout to optimize transmission of data packets in a TCP communication system. In one embodiment, upon occurrence of an SL, one or more data packets that are missing may be recovered by estimating the RTO based on the network metric. For example, the user equipment 101 may estimate SRTT and Round Trip Time Variance (RTTVAR), and update the RTO based on the estimated SRTT and RTTVAR.

In one embodiment, upon occurrence of the BL, the missing one or more data packets may be recovered by determining a dynamic RTO based on a state of an edge node and a mobility parameter provided based on a current network state. have. In addition, one or more missing data packets may be recovered based on coordinated SNOOP and Automatic Repeat Request (ARQ) retransmission. In one embodiment, the dynamic RTO may mean a modified RTO. In one embodiment, the user equipment 101 may trigger a Dup ACK to be sent to the server based on the RTO. When the server receives the Dup ACK, it can reduce the throughput by reducing the size of the congestion window. The user equipment 101 can control the RTO so that the throughput is not significantly reduced due to the instantaneous SL condition.

In one embodiment, when CPL occurs, one or more missing data packets may be recovered by managing a transmission rate of a duplicate acknowledgment (ACK). In an embodiment, managing the Dup ACK may include determining the occurrence of a handover event and calculating a handover time when determining the handover event. In addition, the number of TDA (Triple Dup ACK) transmitted may be determined based on a congestion window (CWND) learned in the server. In one embodiment, the calculated TDA may be shared before the RTO expires, and the number of transmitted TDAs may be adjusted based on the handover time.

In one embodiment, the user equipment 101 is to use a modified RTO to receive the missing data packet, instead of triggering a Dup ACK using a legacy, to receive one or more missing data packets. You can wait for additional time. During the additional time, the user equipment 101 may receive the missing data packet, at which time a Dup ACK may be triggered. If the missing data packet is not received even at the additional time, the missing data packet can be received from the server.

In one embodiment, the Dup ACK is, in TCP communication, when a transmitting end transmits a plurality of segments to a receiving end, when the receiving order of the plurality of segments received by the receiving end does not match the transmission order of the transmitting end, the receiving end occurs It may mean ACK to be made. At this time, since the ACK generated by the receiving end is the same as the ACK for the segment most recently normally received by the receiving end, the transmitted ACK can be recognized as a Dup ACK. In an embodiment, the TCP transmitter may consider that a segment is lost when three triple duplicate ACKs (TDAs) are received, and may perform segment retransmission regardless of the expiration of the retransmission timeout. In the present disclosure, a data packet or a packet refers to a segment transmitted from a TCP transmitting end to a receiving end, and can be used interchangeably.

2 is a flowchart illustrating a method of operating a user equipment (UE) according to an embodiment of the present disclosure. In FIG. 2, the user equipment may refer to a receiving end for receiving a data packet in a wireless TCP communication network.

Referring to FIG. 2, in step 210, the user equipment 101 may identify a missing data packet among a plurality of data packets. For example, in a wireless TCP communication network, the user equipment 101 may identify an omission of at least one data packet among a plurality of data packets transmitted from a transmitting end. In an embodiment, the transmitting end may mean at least one of the user devices of FIG. 1A or a server that is connected to the user devices by wire or wirelessly and transmits a data packet to the receiving end.

In step 220, the user equipment 101 may determine the event that caused the data packet to be dropped. For example, an event that may cause a data packet to be dropped may include spurious loss (SL), burst loss (BL), or continuous packet loss (CPL). In one embodiment, SL may be caused by sudden delay spikes or rearrangements in the network. In addition, BL may occur due to the mobility of the user equipment 101 even if the network is not congested. In addition, CPL may occur due to a handover of the user equipment 101 or the like. Since each of the events described above are independent of each other, one or more events may be combined with each other to occur.

In step 230, the user equipment 101 may set the length of the timer based on the network metric corresponding to the event. In an embodiment, the timer may mean an RTO timer used for retransmission of data packets in a TCP communication network. When the event is determined as SL, the user equipment 101 may set the length of the timer based on the network metric. In addition, when the event is determined as BL, the user equipment 101 may set the length of the timer based on the state of the edge node and the mobility parameter. In addition, when the event is determined to be CPL, the user equipment 101 may receive the missing data packet by using a Dup ACK control method or a probe packet transmission method.

3 is a block diagram of user equipment according to an embodiment of the present disclosure.

Referring to FIG. 3, the user equipment 101 may include an input/output interface 107, a memory 109, and a processor 111. In this case, the memory 109 may include data 300 and modules 211. However, not all of the components shown in FIG. 3 are essential components of the user equipment 101. The user equipment 101 may be implemented by more components than those shown in FIG. 3, or the user equipment 101 may be implemented by fewer components than the components shown in FIG. 3.

In one embodiment, data 300 may include data packet 301, RTO timer data 303, event data 305, network metric data 307 and other data 309. The data packet 301 may include data packets received from the user device. Also, the data packet 301 may include details regarding one or more data packets that are missing.

In one embodiment, the RTO timer data 303 may include details regarding the initiated RTO time for one or more data packets that are missed. Details may include the time interval required to wait to receive one or more missing data packets. Further, the RTO timer data 303 may include details regarding the modified RTO timer generated based on the network metric.

In one embodiment, event data 305 may include details regarding one or more events. In this case, the event may mean any event that causes the data packet to be omitted when the data packet is transmitted. For example, one or more events may include at least one of SL, BL, or CPL. Event data 305 may include details related to losses that may be triggered during data transmission.

In one embodiment, the network metric data 307 may include details regarding a network metric that is calculated based on a current network state in which a plurality of data packets are transmitted. For example, the network metric may include a signal-to-interface-plus-noise ratio (SINR), a delay generated in an access network, a burst reassembly delay, and the like. In one embodiment, the network metric may be expressed as a positive or negative integer.

In one embodiment, the other data 309 may store data including temporary data and temporary files generated by modules 311 for performing various functions of the user equipment 101.

In one embodiment, data 300 in memory 109 may be processed by modules 311 included in memory 109 of user equipment 101. In this case, the modules 311 may mean one or more modules. In one embodiment, the modules 311 may be implemented as dedicated units. As described in the present disclosure, the term module refers to a specific integrated circuit (ASIC), an electronic circuit, a field-programmable gate arrays (FPGA), a programmable system-on-chip, PSoC), a combinational logic circuit, and/or other suitable components that provide the described functionality. In one embodiment, the modules 311 may be communicatively connected by the processor 111 to perform one or more functions of the user equipment 101. When configured with the functions defined in this disclosure, the modules 311 may result in new hardware.

In one embodiment, the modules 311 include a receiving module 313, a data packet identification module 315, an RTO timer initiation module 317, a network metric calculation module 319, a modified RTO generation module 321, and Other modules 323 may be included. In addition, the modules 211 may include other modules 323 to perform various miscellaneous functions of the user equipment 101. In one embodiment, the other modules 323 may include a data packet recovery module capable of recovering one or more missing data packets from an end server after the dynamic RTO expires.

In one embodiment, the data packet recovery module may recover one or more missing data packets based on the occurrence of one or more events. For example, when an SL occurs, the data packet recovery module may estimate the RTO based on the network metric. In addition, when BL occurs, the data packet recovery module may recover one or more missing data packets. For recovery, an edge node state may be provided based on a current network state, and a dynamic RTO may be determined based on a mobility parameter. In one embodiment, the mobility parameter may mean an access network delay and a burst reassembly delay.

In addition, one or more missing data packets may be recovered based on adjusted snoop and ARQ retransmissions. Similarly, when CPL occurs, one or more missing data packets can be recovered by managing the transmission rate of a duplicate ACK (Dup ACK). The redundant ACK can be managed by calculating the handover time when determining the occurrence of a handover event and determining the handover event. The number of transmitted triple duplicate ACKs (TDAs) may be determined based on a congestion window (CWND) learned in the server so that the calculated TDA is shared before the RTO expires. Accordingly, the number of TDAs to be transmitted may be adjusted based on the handover time. In one embodiment, adjusting may include tuning or controlling the number of TDAs.

In an embodiment, the receiving module 313 may receive at least one data packet from among a plurality of data packets transmitted by at least one of the user devices. A plurality of data packets may be transmitted through the WTCP communication system.

In one embodiment, the data packet identification module 315 may identify missing one or more data packets from among a plurality of received data packets based on the occurrence of one or more events. In one embodiment, one or more events may include SL, BL or CPL. In one embodiment, the type of events may be determined based on the identification of missing one or more data packets.

In an embodiment, the RTO timer start module 317 may start the RTO timer during a time interval waiting to receive one or more missing data packets until the RTO timer expires. In one embodiment, the time interval may be a predefined time interval and may be changed based on the type of operating system (or TCP implementation) used in the user equipment 101.

In an embodiment, the network metric calculation module 319 may calculate a network metric based on a current network state in which a plurality of data packets are transmitted. In one embodiment, the network metric may be a positive integer or a negative integer. In an embodiment, the current network state may be identified based on a signal to noise ratio (SNR), a received signal strength indicator (RSSI), handover, and the like. In one embodiment, the network condition may change dynamically based on the mobility of the user associated with the user equipment 101.

In one embodiment, the modified RTO generation module 321 may modify the RTO timer based on the calculated network metric to receive one or more missing data packets.

4 shows an example of a wireless filter according to an embodiment of the present disclosure.

Referring to FIG. 4, in an embodiment, the wireless filter may include an RTO filter. The RTO filter can be used to identify the value of the RTO timer and network metrics. In one embodiment, the network metric may provide information related to fluctuation in the network based on SINR, RSSI, handover, random access technology (RAT), and the like. For example, the network metric may include delay and burst reassembly delay occurring in the access network. In this case, the network metric may be expressed as a positive integer or a negative integer. In one embodiment, the RTO can be more accurately estimated by network metrics.

5 is an exemplary flowchart of an operation of an RTO filter according to an embodiment of the present disclosure.

Referring to FIG. 5, FIG. 5 shows an exemplary flowchart for an RTO filter according to an embodiment of the present disclosure. As shown in Fig. 5, the RTO filter can keep track of the estimated state of the system and the variance or uncertainty of the estimate. The estimate can be updated using a state transition model and measurements. As shown, X _{K | K-1} represents the estimation of the state of the system at time step k before the _kth measurement y _k is considered, and P _{K | K-1} represents the uncertainty in the estimation of the system state.

The operation of the RTO filter illustrated in FIG. 5 will be described in detail. In FIG. 5, the RTO filter may estimate P and X at the k-th time using a previous Round Trip Time (RTT). The RTO filter is the state of the system in the k-1 time step X _{K-1 | K-1} and uncertainty P _{K-1 | In K-1} , handover or mobility of the user equipment 101 can be predicted. Through these predictions, the RTO filter determines the state of the system at k time steps X _{K | K-1} and uncertainty P _{K |} You can get _K-1 . In addition, the RTO filter may measure network metrics through modem detection. Thereafter, the RTO filter is the state of the system at k time steps X _{K | K-1} and uncertainty P _{K | K-1} can be updated with measurements. That is, the RTO filter is the state of the system at k time steps X _{K | K-1} and uncertainty P _{K | K-1} may be updated based on the measured network metric. By updating, the RTO filter is the state of the system where the _kth measurement y _k is taken into account X _{K | K} and uncertainty P _{K | K} can be obtained. The RTO filter is in the state of the system X _{K | K} and uncertainty P _{K | The} estimated RTO can be output using _K , the time k can be changed to k+1, and the algorithm shown in FIG. 5 can be performed again.

6 is an exemplary diagram related to a spurious loss (SL) according to an embodiment of the present disclosure.

Referring to FIG. 6, when SL is generated, an RTO may be estimated based on a network metric. In one embodiment, the network metric may provide information related to fluctuations in the network based on SNR or RSSI. RTO can be more accurately estimated by network metrics. In one embodiment, metric generation, fluctuation detection, and SL detection operations may be performed by a cellular processor (CP) included in the user equipment 101. In addition, a network metric generation operation may be performed by an application processor (AP) included in the user equipment 101. The operation of the user equipment 101 including the CP and AP will be described in detail below.

로 나타내어질 수 있고,

는 X 및 Y에 기초하여 결정될 수 있다. 일 실시 예에서, X는 엑세스 네트워크에서 발생한 지연(delay incurred in the access network), Y는 버스트 리어셈블리 지연(burst reassembly delay)에 의해 결정되는 값을 의미할 수 있다.In one embodiment, user equipment 101 may identify the occurrence of an SL event. In addition, the user equipment 101 can detect fluctuations. For example, after obtaining information on a network metric through IPC (inter process communication), it is possible to detect a change in a network state. In addition, the user equipment 101 may generate a metric. For example, the metric is

Can be represented by

May be determined based on X and Y. In an embodiment, X may be a delay incurred in the access network, and Y may be a value determined by a burst reassembly delay.

7 is an exemplary sequence diagram for recovering lost data packets when a burst loss (BL) occurs according to an embodiment of the present disclosure. In FIG. 7, the SNOOP and ARQ blocks, the core block, and the TCP block may be included in the user equipment 101 and may represent different layers. In Fig. 7, the movement of a data packet can be indicated by an arrow.

Referring to FIG. 7, the sequence diagram of FIG. 7 shows a state in which bursts of packets are lost or delayed due to mobility of the user equipment 101. In this state, the modem can inform the state of mobility to the TCP stack, so the TCP stack can wait 2X+2Y hours in addition to the previous RTO. Through this, there are RTTVAR _t at time t can be calculated as the <Equation 1> below.

는 일반적으로 1/4가 사용되고, X는 엑세스 네트워크에서 발생한 지연(delay incurred in the access network), Y는 버스트 리어셈블리 지연(burst reassembly delay)을 의미할 수 있다. 일 실시예에서, 2X+2Y는

로 나타내어질 수 있다.In <Equation 1>, RTTVAR _t means the variance of RTT at time t, RTTVAR _t-1 means the variance of RTT at time t-1, and SRTT means smoothened RTT. Means, ERTT means estimated RTT,

In general, 1/4 is used, X may indicate a delay incurred in the access network, and Y may indicate a burst reassembly delay. In one embodiment, 2X+2Y is

It can be represented by

In one embodiment, even in a state in which the network is not congested, retransmission may occur due to the mobility of the user equipment 101. In an embodiment, the modem may provide the edge cell condition reactively according to a current condition or proactively based on a previous mobility. In one embodiment, a dynamic timer based on mobility may be determined, and packets may be recovered using the adjusted SNOOP, ARQ and TCP recovery methods. Since lower layer recovery is abstracted at the TCP layer, server-side CWND may not be scaled down.

In one embodiment, a method of setting the RTO based on the adjusted SNOOP and ARQ is as follows. First, due to the mobility of the user equipment 101, a burst of packets may be lost or delayed. Thereafter, the modem can inform the TCP stack about the mobility condition, and the TCP stack can wait for the above-described 2X+2Y time from the previous RTO time. In one embodiment, snoop and ARQ level retransmission may occur, through which data packets may be recovered. In one embodiment, if loss of actual packets occurs, the lost data packets can be recovered from the end server after a timeout.

In an embodiment, when the user equipment 101 handovers to the LTE region in the 5G region operating in millimeter wave (mmWave), BL may occur. Under these conditions, the legacy RTO may take 20 to 30 seconds or more to adapt to the handover situation. On the other hand, the user equipment 101 according to the exemplary embodiment of the present disclosure may avoid unnecessary retransmission of the ACK packet by applying a shift in the signal domain within 1 to 2 seconds. In addition, when CPL occurs, data packets may be recovered based on at least one of a controlled Dup ACK filter approach, a probe-based approach, and a CPL probe approach.

8 illustrates an example for recovering missing data packets when a continuous packet loss (CPL) occurs using a filter method according to an embodiment of the present disclosure.

Referring to FIG. 8, when CPL occurs, a cellular processor (CP) filter may recover one or more missing data packets by managing a transmission rate of a Dup ACK. Dup ACK can be managed by determining the occurrence of a handover event and calculating a handover time when determining the handover event. In one embodiment, the number of TDAs transmitted to the CP filter may be determined based on the congestion window learned in the server so that the TDA calculated before the RTO expires is shared. Accordingly, the number of TDAs to be transmitted may be adjusted based on the handover time. In one embodiment, adjusting may include tuning or controlling the number of TDAs.

Unlike other loss events, when the user equipment 101 handovers, packets may be continuously lost. At this time, the loss is not sporadic, so it can be recovered in the server. Referring to this, the operation of the CP filter shown in FIG. 8 will be described in detail below.

The CP filter may detect that a handover (HO) event has occurred. Accordingly, the CP filter may calculate a handover time, which means a time from initiation of handover to completion of handover. In one embodiment, a filter-based approach can be used to pacing Dup ACKs. In one embodiment, the CP filter may recognize the CWND of the server side and pacing the TDA. The CP filter checks whether the TDA is shared before the timeout occurs, and exponentially reduces the TDA, thereby running the server. In FIG. 8, it is illustrated that the paced Dup ACK is simultaneously output from the CP filter, but is not limited thereto. That is, the paced Dup ACKs are not simultaneously output from the filter, but may be output in a different order.

9 is an exemplary sequence diagram for recovering missing data packets when CPL occurs, using a probe method according to an embodiment of the present disclosure.

Referring to FIG. 9, the user equipment 101 may initially detect the start of BL/CPL. Thereafter, information on the detection of BL/CPL may be indicated to the server using signaling. In this condition, the server may halt or store the processing of TCP metrics or network metrics before signaling. In one embodiment, halt may mean that the value is frozen for a short period of time. In this case, the value is not separately stored as an external value, but may not be separately decreased or increased during probing. In addition, the user equipment 101 may stop processing or store network parameters such as RTO, SRTT, RWND (Receiver Window), next expected sequence number, ACK number, and the like. For example, when the CWND (Congestion Window) is 200, the SSTHRESH (Slow-Start Threshold) may be 250, the CWND value and the SSTHRESH values may be stored, and processing may be stopped until the probe is successful. .

In one embodiment, probed data packets may hit or drop an Internet Control Message Protocol (ICMP) message until the data packets are recovered and a success probe ACK is received. have. In this condition, the server can restore data packets to previous values and quickly retransmit lost data packets to start quick recovery.

The operation of the user equipment 101 and the server illustrated in FIG. 9 will be described in detail below. First, the user equipment 101 may detect the start of BL/CPL. Thereafter, the user equipment 101 may signal information on BL/CPL to the server. In this case, signaling from the user equipment 101 to the server may mean transmission of a probe packet. In one embodiment, the information on the BL/CPL may include information on the period of the BL/CPL. After signaling, the server can recognize that the user equipment 101 is in the BL/CPL phase. The server may stop processing or store TCP metrics prior to the signaling phase. In this case, stopping the processing of the TCP metric may mean fixing the TCP metric value without changing it for a specific time.

In an embodiment, the user equipment 101 may also stop processing or store the processing of client side parameters. For example, the client-side parameter may mean RTO, SRTT, RWND, next expected sequence number, ACK, and the like. For example, the CWND value may be 200 and the SSTHRESH value may be 250, and these values may be stored until the probing operation is successful. The user equipment 101 may detect the termination of BL/CPL, and may receive a success probe ACK (ACK) from the server. The server can perform data retransmission for quick recovery using the stored values.

10 is an exemplary flowchart for recovering missing data packets when CPL occurs, using a probe method according to an embodiment of the present disclosure. In FIG. 10, the server may refer to a transmitting end that transmits a data packet in a wireless TCP communication network, and the user equipment 101 may refer to a receiving end that receives a data packet, but is not limited thereto.

Referring to FIG. 10, the user equipment 101 may detect a CPL event. That is, the user equipment 101 may detect the occurrence of a CPL event while receiving a data packet from the server.

In step 1005, the user equipment 101 may stop processing the actual packet. For example, when a CPL event is detected, the user equipment 101 may stop an original session that received data from a server as a receiving end.

In step 1010, the user equipment 101 may instruct the server. For example, the user equipment 101 may instruct the server to detect a CPL event. In response to this, the server may stop actual transmission and reception (TX/RX) in step 1040.

In step 1015, the user equipment 101 may transmit the probe packet time. That is, the user equipment 101 may transmit a probe packet in the role of a sender in a session independent from the original session. In one embodiment, the probe packet time T may mean RTT. In this case, the index N may be 0. The server may store the previous CWND and the previous SSTHRESH in step 1045.

In step 1020, the user equipment 101 may determine whether the probe is successful. For example, the user equipment 101 may receive an ACK for the transmitted probe packet from the server and determine whether the probe transmission is successful. For example, if the user equipment 101 does not receive an ACK related to a successful probe transmission, it may determine a probe transmission failure and perform step 1025.

In step 1025, the user equipment 101 may update the probe packet time T to N+T. In addition, the user equipment 101 may update the index N to N+1. When the user equipment 101 receives the ACK related to the success of the probe transmission, the user equipment 101 may determine the success of the probe transmission and perform step 1030.

In step 1030, the user equipment 101 may determine completion of the probe. That is, after determining the success of the probe packet transmission, the user equipment 101 may determine the completion of the probe packet transmission. Correspondingly, in step 1050, the server may use the previous CWND and the previous SSTHRESSH.

In step 1035, the user equipment 101 may start an actual packet. That is, the user equipment 101 may receive an actual data packet from the server in the original session.

11 is a performance graph related to RTO setting when BL occurs according to an embodiment of the present disclosure.

Referring to FIG. 11, the graph shown in FIG. 11 may represent a situation in which a user equipment 101 related to a user moves from a good signal area to a weak signal area. For example, the situation of FIG. 11 may refer to a situation in which the user equipment 101 is handed over to the LTE area in the 5G area operating in millimeter wave (mmWave). Under these conditions, the legacy RTO may take 20 to 30 seconds or more to adapt to the handover situation. On the other hand, the user equipment 101 according to the exemplary embodiment of the present disclosure may avoid unnecessary retransmission of the ACK packet by applying a shift in the signal domain within 1 to 2 seconds. In addition, when CPL occurs, data packets may be recovered based on at least one of a controlled Dup ACK filter approach, a probe-based approach, and a CPL probe approach.

12 is a performance graph related to RTO setting when CPL occurs according to an embodiment of the present disclosure.

Referring to FIG. 12, the graph shown in FIG. 12 shows a situation in which a user equipment 101 associated with a user moves from a weak signal area to a good signal area. In these conditions, the user equipment 101 can apply the modified RTO. As shown in FIG. 11, the new RTO graph 1210 associated with the user equipment 101 in the present disclosure may be closer to the graph 1220 associated with the current RTT than the graph associated with the legacy RTO. Thus, in the event of a real loss, the user equipment 101 can adapt to the situation much more quickly using the modified new RTO.

13 is a flowchart illustrating a method of operating user equipment according to an embodiment of the present disclosure. In FIG. 13, the user equipment 101 may refer to a receiving end that receives a data packet in a wireless TCP communication network. Also, the TCP user device may mean a transmitting end that transmits a data packet.

Referring to FIG. 13, in step 1310, the user equipment 101 may receive data packets from a TCP user device. That is, the user equipment 101 may receive at least one data packet from among a plurality of data packets transmitted by the TCP user device. In one embodiment, at least one data packet may be received by the receiving module 313 included in the user equipment 101.

In step 1320, the user equipment 101 may identify a missing data packet among the received data packets based on the occurrence of the event. In one embodiment, an event that may cause a data packet to be dropped may include SL, BL or CPL. In one embodiment, missing data packets may be identified by a data packet identification module 315 included in user equipment 101.

In step 1330, the user equipment 101 may start the RTO timer during a time interval waiting to receive the missing data packet until the expiration of the RTO timer. In one embodiment, the RTO timer may be generated and started by the RTO timer start module 317 included in the user equipment 101.

In operation 1340, the user equipment 101 may calculate a network metric based on a current network state in which a plurality of data packets are transmitted. In one embodiment, the network metric may be calculated by the network metric calculation module 319 included in the user equipment 101.

In step 1350, the user equipment 101 may generate a modified RTO timer based on the calculated network metric to receive the missing data packet. In one embodiment, the modified RTO timer may be generated by the modified RTO generation module 321 included in the user equipment 101. User equipment 101 may wait for retransmission from the server for one or more missing data packets during the modified RTO timer time. By the modified RTO timer, transmission and reception of data packets in a wireless TCP communication system can be optimized.

The method shown in FIG. 13 can be described in the general context of computer-executable instructions. In general, computer-executable instructions are routines, programs, objects, components, data structures, and procedures that perform specific functions or implement specific abstract data types. S, modules, and functions. The order in which the method illustrated in FIG. 13 is described is not intended to be construed as limiting, and the described method blocks having any number may be combined in any order to implement the method. Further, individual blocks may be deleted from the methods without departing from the scope of the subject matter described in this disclosure. In addition, the method may be implemented in any suitable hardware, software, firmware, or a combination thereof.

14 is a detailed block diagram of user equipment according to an embodiment of the present disclosure. The user equipment 1400 shown in FIG. 14 may mean the user equipment 101 shown in FIG. 1A, and the communication network 1409 shown in FIG. 14 means the communication network 105 shown in FIG. 1A. In addition, the user device 1414-1, the user device 1414-2, and the user device 1414-N (hereinafter, user devices 1414) shown in FIG. 14 are the user devices shown in FIG. 1A. It can mean devices.

Referring to FIG. 14, the user equipment 1400 may include a central processing unit (CPU or processor) 1402. The processor 1402 may include at least one data processor for optimizing transmission of data packets in a wireless TCP communication system. The processor 1402 may include an integrated system (bus) controller, a memory management control unit, a floating point unit, a graphics processing unit, a special processing unit such as a digital signal processing unit, and the like.

The processor 1402 may be arranged to communicate with one or more input/output devices (not shown) through the input/output interface 1401. The input/output interface 1401 is audio, analog, digital, mono audio (monoaural), RCA, stereo, IEEE-1394, serial bus, USB (universal serial bus), infrared, PS/2, BNC, coaxial, component, composite digital visual interface (DVI), high-definition multimedia interface (HDMI), RF antenna, S-Video, VGA (Video) Graphics Array), IEEE 802.n /b/g/n/x, Bluetooth, cellular (e.g., code-division multiple access (CDMA), HSPA+ (high-speed packet access)) , A communication protocol or method such as global system for mobile communications (GSM), long-term evolution (LTE), WiMAX, etc.) may be supported without limitation.

The user equipment 1400 may communicate with one or more input/output devices using the input/output interface 1401. For example, the input devices 1412 include an antenna, a keyboard, a mouse, a joystick, a (infrared) remote control, a camera, a card reader, a fax machine, a dongle, a biometric reader, a microphone, a touch screen, and a touch device. Pads, trackballs, stylus, scanners, storage devices, transceivers, video devices/sources, and the like. Output devices 1413 include a printer, a fax machine, a video display (e.g., a cathode ray tube (CRT), a liquid crystal display (LCD)), a light-emitting diode (LED), a plasma, It may include a plasma display panel (PDP), an organic light-emitting diode display (OLED), and an audio speaker.

The processor 1402 may be arranged to communicate with the communication network 1409 through the network interface 1403. The network interface 1403 may communicate with the communication network 1409. Network interface 1403 is direct connection, Ethernet (Ethernet) (for example, twisted pair 10/100/1000 Base T), transmission control protocol/Internet protocol (TCP/IP), token ring, IEEE 802.11a/b/ You can use g/n/x without limitation. The communication network 1409 may include, without limitation, direct interconnection, a local area network (LAN), a wide area network (WAN), a wireless network (eg, using a wireless application protocol), and the Internet. Using the network interface 1403 and the communication network 1409, the user equipment 1400 can be configured with user devices such as user device 1414-1, user device 1414-2, and user device 1414-N. 1414). The network interface 1403 is a direct connect, Ethernet (eg, twisted pair 10/100/1000 Base T), transmission control protocol/Internet protocol (TCP/IP), token ring, IEEE 802.11a/b/g Connection protocols including /n/x can be used without any restrictions.

The communication network 1409 restricts direct interconnect, e-commerce networks, peer to peer (P2P) networks, LANs, WANs, wireless networks (e.g. using wireless application protocols), Internet and Wi-Fi, etc. Can be included without. The first network and the second network are dedicated networks, or of different types of networks that use various protocols such as HTTP (Hypertext Transfer Protocol), TCP/IP, and Wireless Application Protocol (WAP) to communicate with each other. It may be a shared network showing association. Further, the first network and the second network may include various network devices including routers, bridges, servers, computing devices, storage devices, and the like.

In one embodiment, the processor 1402 may be arranged to communicate with the memory 1405 (eg, RAM, ROM, etc., not shown in FIG. 14) through the storage interface 1404. The storage interface 1404 is a connection protocol such as serial advanced technology attachment (SATA), Integrated Drive Electronics (IDE), IEEE-1394, Universal Serial Bus (USB), fiber channel, Small Computer Systems Interface (SCSI), etc. Can be used without limitation, and can be connected to memory 1405, including memory drives and removable disk drives. Memory drives include drums, magnetic disc drives, magneto-optical drives, optical drives, RAID (Redundant Array of Independent Discs), and solid state It may include a memory device, a drive using a semiconductor, and the like.

The memory 1405 may store a set of program or database components including, without limitation, a user interface 1406, an operating system 1407, and the like. In one embodiment, user equipment 1400 may store user/application data such as data, variables, records, and the like as described in this disclosure. These databases can be implemented as fault-tolerant, relational, scalable, and secure databases such as Oracle or Sybase.

The operating system 1407 may facilitate resource management and operation of the user equipment 1400. For example, the operating system is APPLE MACINTOSH ^R OS X, UNIX ^R , UNIX-like system distributions (EG, BERKELEY SOFTWARE DISTRIBUTION ^TM (BSD), FREEBSD ^TM , NETBSD ^TM , OPENBSD ^TM , etc.), LINUX DISTRIBUTIONS ^TM ( EG, RED HAT ^TM , UBUNTU ^TM , KUBUNTU ^TM , etc.), IBM ^TM OS/2, MICROSOFT ^TM WINDOWS ^TM (XP ^TM , VISTA ^TM /7/8, 10 etc.), APPLE ^R IOS ^TM , GOOGLE ^R ANDROID ^TM , BLACKBERRY ^R OS, etc. may be included without limitation.

In one embodiment, the user equipment 1400 may implement the stored program component as a web browser 1408. Web browser 1408 may ^{be, MICROSOFT ® INTERNET EXPLORER TM, GOOGLE} ® CHROME TM, MOZILLA ® FIREFOX TM, APPLE ® SAFARI TM and hypertext (hypertext) watching epeulrikeyisyeon (hypertext viewing application) the same. Secure web browsing can be provided using secure HTTPS (Hypertext Transport Protocol), SSL (Secure Sockets Layer), TLS (Transport Layer Security), and the like. Web browser 1408 can take advantage of features such as ^{AJAX TM, DHTML TM, ADOBE ®} FLASH TM, JAVASCRIPT TM, JAVA TM, (Application Programming Interfaces) APIs. In some embodiments, user equipment 101 may implement a mail server stored in a program component. The mail server may be an Internet mail server such as Microsoft Exchange. The mail server can use features such as ASP ^TM , ACTIVEX ^TM , ANSI ^TM C++/C#, MICROSOFT ^® , NET ^TM , CGI SCRIPTS ^TM , JAVA ^TM , JAVASCRIPT ^TM , PERL ^TM , PHP ^TM , PYTHON ^TM , WEBOBJECTS ^TM . Mail server may use a communication protocol such as (Internet Message Access Protocol) IMAP, (Messaging Application Programming Interface) MAPI, MICROSOFT ® exchange, POP (Post Office Protocol), SMTP (Simple Mail Transfer Protocol). In some embodiments, user equipment 1400 may implement a mail client stored in a program component. The mail client may be a mail viewing application such as APPLE ^® MAIL ^TM , MICROSOFT ^® ENTOURAGE ^TM , MICROSOFT ^® OUTLOOK ^TM , MOZILLA ^® THUNDERBIRD ^TM .

However, not all of the components shown in FIG. 14 are essential components of the user equipment 1400. The user equipment 1400 may be implemented by more components than the components shown in FIG. 14, or the user equipment 1400 may be implemented by fewer components than the components shown in FIG. 14.

A description will be given of the SNOOP method used when recovering the above-described missing data packet. Snoop may mean a protocol that maintains un-acknowledged TCP segment information in a base station (BS). In one embodiment, the ARQ SNOOP agent may mean a software module designed to use a link layer AQR scheme using TCP in a wireless LAN environment. These software modules can operate within the protocol stack between the TCP and MAC layers.

Two mechanisms, such as packet loss detection and packet loss hiding in the wireless network (dropping duplicate packet in the BS), may require modification at both the user equipment and the base station.

In one embodiment, the W-TCP may adjust the SNOOP to move from the base station to the user equipment. The method according to an embodiment may protect a sender from a congestion loss event by calculating a SNOOP timer and discarding retransmission due to a radio transmission error.

According to an embodiment of the present disclosure, a user device as a sender may be shielded from a radio link error. Also, according to an embodiment of the present disclosure, overhead of a link layer may be removed. In addition, an embodiment of the present disclosure is event-based, and thus, may require very little power consumption. An embodiment of the present disclosure provides a solution for optimizing data transmission at the user equipment level, and thus the need for any modification at the base station or other network entity can be eliminated.

According to an embodiment of the present disclosure, a method of operating a terminal in a wireless communication system includes: identifying an omission of at least one data packet among a plurality of data packets transmitted from another terminal; Determining an event that caused the at least one data packet to be dropped; And setting a length of a timer for receiving the at least one missing data packet based on a network metric corresponding to the determined event.

According to an embodiment, the event may include at least one of Spurious Loss (SL), Burst Loss (BL), or Consecutive Packet Loss (CPL).

According to an embodiment, the setting of the length of the timer includes setting the length of the timer based on a network metric corresponding to the SL when the event is determined as SL, and The corresponding network metric may include at least one of the estimated SRTT or RTTVAR.

According to an embodiment, the setting of the length of the timer includes: when the event is determined as BL, determining a state of an edge node corresponding to a network state of the terminal; And setting the length of the timer based on at least one of the determined state of the edge node or the mobility parameter.

According to an embodiment, based on coordinated snoop and automatic repeat request (ARQ) retransmission, the step of receiving the at least one missing data packet during the set timer length may be further included. .

According to an embodiment, when the event is determined as CPL, the step of controlling the transmission rate of a duplicate (Dup) ACK transmitted from the terminal to the other terminal may be further included.

According to an embodiment, the controlling of the transmission rate of the Dup ACK includes: determining occurrence of a handover of the terminal; Calculating a time required for the generated handover; And adjusting the number of Triple Dup ACKs (TDA) based on the calculated time.

According to an embodiment, it may further include receiving the at least one missing data packet from the other terminal during the set timer length.

According to an embodiment, the receiving of the missing at least one data packet may include transmitting a probe packet to the other terminal when the event is determined as BL or CPL; And in response to receiving an ACK for the transmitted probe packet, receiving at least one missing data packet retransmitted from the other terminal.

According to an embodiment of the present disclosure, in a wireless communication system, a terminal includes an input/output interface; A memory for storing one or more instructions; And at least one processor that executes the one or more instructions stored in the memory, wherein the at least one processor identifies an omission of at least one data packet among a plurality of data packets transmitted from another terminal, and the An event that caused at least one data packet to be dropped may be determined, and a length of a timer for receiving the at least one missing data packet may be set based on a network metric corresponding to the determined event.

According to an embodiment, the event may include at least one of Spurious Loss (SL), Burst Loss (BL), or Consecutive Packet Loss (CPL).

According to an embodiment, when the event is determined as SL, the at least one processor sets the length of the timer based on a network metric corresponding to the SL, and the network metric corresponding to the SL is estimated It may include at least one of SRTT or RTTVAR.

According to an embodiment, when the event is determined as BL, the at least one processor determines a state of an edge node corresponding to the network state of the terminal, and the determined state or mobility of the edge node The length of the timer may be set based on at least one of the parameters.

According to an embodiment, the at least one processor may receive the at least one missing data packet during the set timer length based on coordinated snoop and automatic repeat request (ARQ) retransmission. I can.

According to an embodiment, when the event is determined as CPL, the at least one processor may control a transmission rate of a duplicate (Dup) ACK transmitted from the terminal to the other terminal.

According to an embodiment, the at least one processor determines the occurrence of handover of the terminal, calculates a time required for the generated handover, and based on the calculated time, TDA (Triple Dup ACK) The number of) can be adjusted.

According to an embodiment, the at least one processor may receive the missing at least one data packet from the other terminal during the set timer length.

According to an embodiment, the at least one processor transmits a probe packet to the other terminal when the event is determined to be BL or CPL, and in response to receiving an ACK for the transmitted probe packet, the other terminal At least one missing data packet retransmitted from may be received.

Identifying an omission of at least one data packet from among a plurality of data packets transmitted from the transmitting end; Determining an event that caused the at least one data packet to be dropped; And setting a length of a timer for receiving the at least one missing packet based on a network metric corresponding to the determined event.

In one embodiment, the event may include at least one of Spurious Loss (SL), Burst Loss (BL), or Consecutive Packet Loss (CPL).

Setting the length of the timer according to an embodiment may include setting the length of the timer based on a network metric corresponding to the SL when the event is determined as SL.

Setting the length of the timer according to an embodiment includes: when the event is determined to be BL, determining a state of an edge node corresponding to a network state of the receiving end; And setting the length of the timer based on at least one of the determined state of the edge node or the mobility parameter.

An operating method of a receiving end according to an embodiment includes receiving the at least one missing data packet during the set timer length based on coordinated snoop and automatic repeat request (ARQ) retransmission. It may contain more.

The operating method of the receiving end according to an embodiment may further include controlling a transmission rate of a duplicate (Dup) ACK transmitted from the receiving end to the transmitting end when the event is determined as CPL.

The controlling of the transmission rate of the Dup ACK according to an embodiment includes: determining the occurrence of a handover of the receiving end; Calculating a time required for the generated handover; And adjusting the number of Triple Dup ACKs (TDA) based on the calculated time.

The operating method of the receiving end according to an embodiment may further include receiving the at least one missing data packet from the transmitting end during the set timer.

Receiving the at least one missing data packet according to an embodiment includes: when the event is determined as BL or CPL, transmitting a probe packet to the transmitter; And in response to receiving an ACK for the transmitted probe packet, receiving at least one missing data packet retransmitted from the transmitting end.

According to an embodiment of the present disclosure, in a wireless communication system, a receiving end includes an input/output interface; A memory for storing one or more instructions; And identifying an omission of at least one data packet among a plurality of data packets transmitted from the transmitting end, determining an event that caused the omission of the at least one data packet, and based on a network metric corresponding to the determined event, It may include at least one processor that executes the one or more instructions to set a length of a timer for receiving the at least one missing packet.

In one embodiment, the event may include at least one of Spurious Loss (SL), Burst Loss (BL), or Consecutive Packet Loss (CPL).

In an embodiment, when the event is determined to be SL by executing the one or more instructions, the at least one processor may set the length of the timer based on a network metric corresponding to the SL.

In one embodiment, the at least one processor, when the event is determined as BL by executing the one or more instructions, determines a state of an edge node corresponding to the network state of the receiving end, and the The length of the timer may be set based on at least one of the determined state of the edge node or the mobility parameter.

In one embodiment, the at least one processor, based on coordinated snoop and ARQ (Automatic Repeat Request) retransmission by executing the one or more instructions, the missing at least during the length of the set timer One data packet can be received.

In one embodiment, the at least one processor, by executing the one or more instructions, when the event is determined as CPL, controls the transmission rate of a duplicate (Dup) ACK transmitted from the receiving end to the transmitting end. I can.

In one embodiment, the at least one processor, by executing the one or more instructions, determines the occurrence of handover of the receiving end, calculates a time required for the generated handover, and based on the calculated time Thus, the number of TDA (Triple Dup ACK) can be adjusted.

In an embodiment, the at least one processor may receive the at least one missing data packet from the transmitting end during the set timer length by executing the one or more instructions.

In one embodiment, the at least one processor, when the event is determined to be BL or CPL, by executing the one or more instructions, transmits a probe packet to the transmitter, and receives an ACK for the transmitted probe packet. Correspondingly, at least one missing data packet retransmitted from the transmitting end may be received.

According to an embodiment of the present disclosure, a computer-readable recording medium includes: identifying an omission of at least one data packet among a plurality of data packets transmitted from another terminal; Determining an event that caused the at least one data packet to be dropped; And a program for setting a length of a timer for receiving the at least one missing data packet based on a network metric corresponding to the determined event.

An embodiment of the present disclosure may also be implemented in the form of a recording medium including instructions executable by a computer, such as a program module executed by a computer. Computer-readable media can be any available media that can be accessed by a computer, and includes both volatile and nonvolatile media, removable and non-removable media. Further, the computer-readable media may include computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media may typically contain computer readable instructions, data structures, or other data in a modulated data signal such as a program module.

In the present disclosure, the term "computer program product" or "computer readable medium" generally refers to a medium such as a memory, a hard disk installed in a hard disk drive, and a signal. Used for These “computer program products” or “computer-readable recording media” are software consisting of instructions for setting the length of a timer for receiving a missing data packet based on a network metric corresponding to a determined event according to the present disclosure. It is a means of providing a computer system.

In addition, in the present disclosure, terms such as "unit" and "module" may be a hardware component such as a processor or a circuit, and/or a software component executed by a hardware configuration such as a processor. .

The "unit" and "module" are stored in an addressable storage medium and may be implemented by a program that can be executed by a processor. For example, "sub" and "module" refer to components such as software components, object-oriented software components, class components and task components, processes, functions, properties, and It can be implemented by procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays and variables.

The specific implementations described in the present disclosure are only an example, and do not limit the scope of the disclosure in any way. For brevity of the specification, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of the systems may be omitted.

In addition, in the present disclosure, “including at least one of a, b or c” means “including only a, only b, only c, including a and b, or including b and c, It may mean including a and c, or including all of a, b and c.

The above description of the present disclosure is for illustrative purposes only, and those of ordinary skill in the art to which the present disclosure pertains will be able to understand that it is possible to easily transform it into other specific forms without changing the technical spirit or essential features of the present disclosure. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present disclosure is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present disclosure. do.

Claims (19)

In the method of operating a terminal in a wireless communication system,
Identifying an omission of at least one data packet among a plurality of data packets transmitted from another terminal;
Determining an event that caused the at least one data packet to be dropped; And
And setting a length of a timer for receiving the at least one missing data packet based on a network metric corresponding to the determined event.
The method of claim 1,
The event includes at least one of Spurious Loss (SL), Burst Loss (BL), or Consecutive Packet Loss (CPL).
The method of claim 2,
Setting the length of the timer,
If the event is determined as SL,
Including the step of setting the length of the timer based on the network metric corresponding to the SL,
The network metric corresponding to the SL includes at least one of an estimated SRTT or RTTVAR.
The method of claim 2,
Setting the length of the timer,
If the event is determined as BL,
Determining a state of an edge node corresponding to a network state of the terminal; And
The method further comprising setting a length of the timer based on at least one of the determined state of the edge node or a mobility parameter.
The method of claim 4,
The method further comprising receiving the at least one missing data packet during the set length of the timer, based on coordinated snoop and automatic repeat request (ARQ) retransmission.
The method of claim 2,
If the event is determined by CPL,
The method further comprising the step of controlling a transmission rate of a duplicate (Dup) ACK transmitted from the terminal to the other terminal.
The method of claim 6,
Controlling the transmission rate of the Dup ACK,
Determining occurrence of handover of the terminal;
Calculating a time required for the generated handover; And
And adjusting the number of Triple Dup ACKs (TDA) based on the calculated time.
The method of claim 2,
And receiving the at least one missing data packet from the other terminal during the set timer length.
The method of claim 8,
Receiving the at least one missing data packet,
If the event is determined as BL or CPL,
Transmitting a probe packet to the other terminal; And
And in response to receiving an ACK for the transmitted probe packet, receiving at least one missing data packet retransmitted from the other terminal.
In a terminal in a wireless communication system,
Input/output interface;
A memory for storing one or more instructions; And
At least one processor for executing the one or more instructions stored in the memory,
The at least one processor,
Identifying omission of at least one data packet among a plurality of data packets transmitted from another terminal,
Determining an event that caused the at least one data packet to be dropped,
A terminal configured to set a length of a timer for receiving the at least one missing data packet based on a network metric corresponding to the determined event.
The method of claim 10,
The event includes at least one of Spurious Loss (SL), Burst Loss (BL), or Consecutive Packet Loss (CPL).
The method of claim 11,
The at least one processor,
If the event is determined as SL,
Set the length of the timer based on the network metric corresponding to the SL,
The network metric corresponding to the SL includes at least one of the estimated SRTT and RTTVAR.
The method of claim 11,
The at least one processor,
If the event is determined as BL,
Determine the state of the edge node corresponding to the network state of the terminal,
A terminal configured to set the length of the timer based on at least one of the determined state of the edge node or a mobility parameter.
The method of claim 13,
The at least one processor,
Based on coordinated snoop and automatic repeat request (ARQ) retransmission, the terminal receives the at least one missing data packet for the length of the set timer.
The method of claim 11,
The at least one processor,
If the event is determined by CPL,
A terminal that controls the transmission rate of a duplicate (Dup) ACK transmitted from the terminal to the other terminal.
The method of claim 15,
The at least one processor,
Determine the occurrence of handover of the terminal,
Calculate the time required for the generated handover,
Terminal for adjusting the number of TDA (Triple Dup ACK) based on the calculated time.
The method of claim 11,
The at least one processor,
During the length of the set timer, the terminal receives the at least one missing data packet from the other terminal.
The method of claim 17,
The at least one processor,
If the event is determined as BL or CPL,
Transmit a probe packet to the other terminal,
A terminal receiving at least one missing data packet retransmitted from the other terminal in response to receiving an ACK for the transmitted probe packet.
Identifying an omission of at least one data packet among a plurality of data packets transmitted from another terminal;
Determining an event that caused the at least one data packet to be dropped; And
A computer-readable recording medium storing a program for performing an operation of setting a length of a timer for receiving the at least one missing data packet based on a network metric corresponding to the determined event.

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