KR100640450B1 - How to receive data from a server supporting TC / IP in a wireless terminal - Google Patents

Abstract

The present invention relates to a method for receiving data from a server supporting TCP / IP (Transmission Control Protocol) / (Internet Protocol) in a wireless terminal. By dividing the response to the data received from the server supporting TCP / IP in a good wireless environment, the server can increase the CWND faster than before, thereby solving the problem of TCP slow start occurring at the beginning of the TCP transmission.

A method for receiving a data from a server supporting TCP / IP by a wireless terminal supporting TCP / IP includes a first step in which the wireless terminal connects to the server to receive predetermined data, the wireless terminal and the server According to a wireless channel situation with the wireless terminal, the wireless terminal divides the response (ACK: ACKnowledge) for the predetermined data into a predetermined number and transmits it to the server. And a third process of receiving data transmitted in units of congestion windows and proceeding to the first process.

Description

Receiving data from a server supporting TC / IP in a wireless terminal {METHOD FOR RECEIVING DATA FROM SERVER FOR TCP / IP}

1 is a network diagram for connecting to a server supporting TCP / IP in a wireless terminal,

2 is a timing diagram illustrating a process of receiving data from a server supporting TCP / IP in a conventional wireless terminal;

3 is a graph showing the increase of CWND according to the TCP slow start algorithm,

4 is a timing diagram illustrating a process of receiving data from a server supporting TCP / IP in a wireless terminal according to an embodiment of the present invention;

5 is a graph showing an increase amount of CWND according to a conventional slow start algorithm and an increase amount of CWND according to a preferred embodiment of the present invention;

6 is a flowchart illustrating a process in which a wireless terminal receives data from a server supporting TCP / IP according to a first embodiment of the present invention;

7 is a flowchart illustrating a process in which a wireless terminal receives data from a server supporting TCP / IP according to a second embodiment of the present invention;

8 is a graph comparing an 802.11 wireless terminal accessing an FTP server using a simulator and receiving 100k bytes of data by dividing a response according to a preferred embodiment of the present invention with a conventional method.

The present invention relates to a method for receiving data from a server supporting TCP / IP (Transmission Control Protocol) / (Internet Protocol) in a wireless terminal.

Researches and various methods for improving performance of receiving data by wirelessly connecting to a server supporting TCP / IP have been proposed, and efforts for practical use have been continued. A fundamental problem in receiving data from a TCP / IP server in a wireless terminal is that the packet drop or packet delay in a wireless network is mistaken for network congestion in a server supporting TCP / IP. To do congestion control.

The following describes the methods of wirelessly receiving data from a server supporting TCP / IP. First, SNOOP, I-TCP (Indirect-TCP), M-TCP (TCP for Mobile Cellular Networks), W-TCP (Wireless-TCP), FDA , NetAccel, etc. This method has a problem of scalability because the proxy server has to manage many TCP connections. Next, there is an Explicit Bad State Notification (ESBN) as a method of Explicit Indication to the server of the situation of a wireless network, which does not work in an existing server that does not use the above method. . In addition, there is TCP Westwood, a method of modifying a server, or Freeze-TCP, a method of modifying a mobile node. Next, a method of receiving a data by connecting to a server supporting TCP / IP by a conventional wireless terminal will be described with reference to the configuration diagram of FIG. 1 and the timing diagram of FIG. 2.

1 is a diagram illustrating a network for accessing a server supporting TCP / IP in a wireless terminal.

The wireless terminal 100 accesses the base station 300 connected to the server 200 and the Internet in order to receive data such as a file or a web page from the server 200 supporting TCP / IP. A process of transmitting data to the wireless terminal 100 by the server 200 in the network configured as described above will be described with reference to the timing diagram of FIG. 2. The timing diagram of FIG. 2 omits the base station 300 in the transmission of data and responses between the wireless terminal 100 and the server 200, and the response transmitted from the wireless terminal 100 is not delayed. Assume (Non Delayed ACK).

2 is a timing diagram illustrating a process of receiving data from a server supporting TCP / IP in a conventional wireless terminal.

TCP is a method of synchronously transmitting data again in response to an ACK (ACKnowledge) for the transmitted data. Therefore, the data transmission speed between the server 200 and the wireless terminal 100 is determined according to the transmission speed of the response. When the server 200 receives a response from the wireless terminal 100, the server 200 increases a congestion window (CWND) by one to increase the data transmission unit by the increased CWND.

According to FIG. 2, when the server 200 receives the ACK 1461, which is a response to the data 1: 1461 originally transmitted from the wireless terminal 100, one CWND is increased to two. Therefore, the server 200 transmits data by increasing the data transmission unit by CWND increased by two. That is, the server 200 continuously transmits data 1461: 2921 and data 2921: 4381 following the first data 1: 1461 to the wireless terminal 100. As such, the server 200 increases the CWND by one each time a response to the data transmitted from the wireless terminal 100 is received until the CWND becomes a stable number. As such, the slow increase until the CWND becomes a stable number is called a TCP slow start algorithm, which is shown in FIG. 3.

3 is a graph showing the increase of CWND according to the TCP slow start algorithm.

According to Figure 3, CWND is increased by one until a stable number x, so the data rate is also increased accordingly. Even if the wireless channel condition between the wireless terminal 100 and the server 200 is in a good state, an increase in CWND has a state as shown in FIG.

Accordingly, an object of the present invention is to provide a method for improving the transmission rate of data received by a wireless terminal from a server supporting TCP / IP.

In order to achieve the above object, a wireless terminal supporting TCP / IP (Transmission Control Protocol) / (Internet Protocol) of the present invention receives a data from a server supporting the TCP / IP. According to a first process of connecting to a server and receiving predetermined data, the wireless terminal divides an acknowledgment (ACK) for the predetermined data into a predetermined number according to a wireless channel situation between the wireless terminal and the server. A second process of transmitting to the server and a third process of receiving data transmitted in increments of congestion windows from the server according to the divided response and proceeding to the first process; It is done.

The wireless terminal supporting TCP / IP and receiving data from the server supporting TCP / IP may require the wireless terminal to request a connection to the server and to determine a wireless channel situation between the wireless terminal and the server. According to the first process of dividing an acknowledgment (ACK: ACKnowledge) for the predetermined data received from the server into a predetermined number and transmitting it to the server, the number of congestion windows increased from the server by the divided response. And a second process of receiving data transmitted in units and proceeding to the first process.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same elements in the figures are represented by the same numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

4 is a timing diagram illustrating a process of receiving data from a server supporting TCP / IP in a wireless terminal according to an exemplary embodiment of the present invention.

According to a preferred embodiment of the present invention, the wireless terminal 400 having a module for dividing the response into a predetermined number is received from the server 500 supporting TCP / IP by operating the module when it is determined that the wireless channel situation is good. Split the number of responses to the data that is being made. The wireless terminal 400 determines whether the wireless channel is good by using a received signal strength indicator (RSSI), a bit error rate (BER), a block error rate (BLER), or the like. The reference point that the radio channel condition is good is that the above method of identifying the radio channel condition statistically calculates the numerical data on the radio channel condition and operates the module to divide the response into a predetermined number so that the network congestion is maintained. It is predetermined to the point where it does not occur. The wireless terminal 400 determines that the wireless channel situation is not good to operate the module when the numerical value calculated by grasping the wireless channel situation by the method described above falls below the reference point. On the other hand, if the calculated value exceeds the reference point, the wireless terminal 400 determines that the wireless channel situation is good to operate the module.

4 illustrates a case in which the wireless terminal 400 operates the module when the numerical value calculated by grasping the wireless channel status by the above method exceeds the reference point. When the wireless terminal 400 first receives data 1: 1461 from the server 500, the wireless terminal 400 divides the response of the wireless terminal 400 into a predetermined number. The predetermined number is a variable set by the wireless terminal 400 according to the identified wireless channel situation, and is determined as a number within a limit in which network congestion does not occur. The predetermined number is also the same as the method of determining the reference point for determining that the radio channel situation is good, in the case where the radio channel situation is determined to be good, so that network congestion does not occur by dividing the response in various ways. The number of cases is predetermined.

In this manner, the wireless terminal 400 determines to divide the response for the first received data 1: 1461 into three and transmits the divided responses to the server 500. The server 500 may confirm receipt of the transmitted data 1: 1461 by receiving the divided responses ACK 467, ACK 973 and ACK 1461. Since the server 500 increments CWND by one each time one response is received, three CWNDs are increased to match three responses received from the wireless terminal 400, and CWND occurs when the first data 1: 1461 is transmitted. In total, it becomes four. Since the server 500 also increases the data transmission unit by the increased CWND, the data following the first transmitted data 1: 1461 after receiving three responses is 1461: 2921, 2921: 4381, 4381: 5841 and 5841: 7301, that is, Composed of a total of four units of data is transmitted to the wireless terminal 400 continuously.

In this manner, each time the wireless terminal 400 receives data from the server 500, the wireless terminal 400 repeats dividing the number of responses until the CWND of the server 200 becomes a stable number. Accordingly, the data rate, which is slowly increased until the CWND becomes a stable number, is further improved, thereby increasing TCP starting performance. The conventional example shown in FIG. 3 compares the increase of CWND until the CWND becomes a stable number through the graph of FIG. 5.

5 is a graph illustrating an increase amount of CWND according to a conventional slow start algorithm and an increase amount of CWND according to a preferred embodiment of the present invention.

According to FIG. 5, the increase amount of CWND according to the preferred embodiment of the present invention is larger than the increase amount of CWND according to the conventional start algorithm until the CWND becomes a stable number. Since the server 500 increases the CWND according to the divided response by dividing the response to the data received by the wireless terminal 400 according to the preferred embodiment of the present invention, the data rate is higher than the conventional CWND increases one by one. . That is, the difference in the portion occupied by CWND until the CWND becomes a stable number indicates that the radio resource is used more efficiently than before.

6 and 7 illustrate a process of dividing a response to data received by the wireless terminal 400 and transmitting the divided data to the server 500 and receiving data corresponding to the increased CWND. It demonstrates in detail with reference. FIG. 6 is a flowchart illustrating a case where the wireless terminal 400 determines the state of a wireless channel before accessing the server 500. FIG. 7 illustrates a situation in which the wireless terminal 400 changes the state of a wireless channel during data transmission. It is a flowchart in the case where it determines that it is favorable and divides a response.

6 is a flowchart illustrating a process in which a wireless terminal receives data from a server supporting TCP / IP according to a first embodiment of the present invention.

The wireless terminal 400 requests a connection to the server 500 of a wired network supporting TCP / IP in order to download data such as a file or a web page for web browsing. At the same time, the wireless terminal 400 determines whether the wireless channel situation is good (S10). The wireless terminal 400 determines the radio channel status by using the RSSI, BER or BLER, etc., and compares the numerical value calculated with the reference point.

As a result, when the calculated value exceeds the reference point and determines that the wireless channel condition is good, the wireless terminal 400 makes a TCP connection with the server 500 (S20). After making a TCP connection, the wireless terminal 400 receives the first data from the server 500 (S30). On the other hand, if it is determined that the wireless channel situation is not good because the calculated value is less than the reference point, the wireless terminal 400 makes a TCP connection (TCP connection) (S100). After making a TCP connection, the wireless terminal 400 receives data from the server 500 (S110). The wireless terminal 400 receiving data from the server 500 transmits a response to the server 500 in a general manner (S120).

On the other hand, the wireless terminal 400 receives the data from the server 500 in step S30 checks whether the number of the transmission response segmentation exceeds the number set according to the wireless channel situation (S40). As described above, the number set according to the wireless channel situation is a variable set according to the wireless channel situation determined by the wireless terminal 400 in step S10, and is determined in advance as a number within a limit in which network congestion does not occur.

Since the wireless terminal 400 receives the first data from the server 500, the wireless terminal 400 divides the response for the first time. Therefore, the wireless terminal 400 divides the response to the first received data according to the wireless channel situation and transmits the divided responses to the server 500 (S50). Accordingly, the server 500 that receives the divided responses from the wireless terminal 400 confirms receipt of the first transmitted data. Since the server 500 increases the CWND by one each time one response is received, the server 500 increases the CWND according to the number of responses received from the wireless terminal 400 in step S50. The server 500 transmits data subsequent to the first transmitted data in data transmission units of the increased CWND, so that the wireless terminal 400 continuously receives data of the number of data transmission units (S30).

The wireless terminal 400 checks again whether the number of splitting response transmissions exceeds the number set according to the wireless channel situation (S30). As a result of the check, if the number of previously transmitted response splits exceeds the number set according to the wireless channel situation, the wireless terminal 400 proceeds to step S120 and transmits a response to the server 500 in a general manner (S100).

On the other hand, if the number of splitting transmission responses does not exceed the number set for the wireless channel situation, the wireless terminal 400 divides the response to the data received from the server 500 according to the wireless channel situation and divides the response. Transmit them (S50). The wireless terminal 400 returns to step S30 after transmitting the responses divided in step S50 (S30). The wireless terminal 400 repeats the steps S10 to S120 until the data transmission from the server 500 is completed.

7 is a flowchart illustrating a process in which a wireless terminal receives data from a server supporting TCP / IP according to a second embodiment of the present invention.

The wireless terminal 400 connects to the server 500 of a wired network supporting TCP / IP to download data such as a file or a web page for web browsing (S200). ). The wireless terminal 400 receives data from the server 500 (S210). After receiving the data, the wireless terminal 400 compares the numerical value calculated using RSSI, BER or BLER with the aforementioned reference point in order to determine whether the wireless channel condition is good (S220).

As a result of comparison, when the calculated value exceeds the reference point and determines that the wireless channel condition is good, the wireless terminal 400 checks whether the number of previously transmitted response divisions exceeds the number set according to the wireless channel condition (S230). On the other hand, if it is determined that the wireless channel situation is not good because the calculated value is less than or equal to the reference point, the wireless terminal 400 generates a response to the data received in step S210 in a general manner to the server 500. Transmit to (S300).

On the other hand, it is determined that the wireless channel situation is good for the first time in step S220 is that the wireless channel situation is not good before, the wireless terminal 400 proceeds to the step S300 and the response to the data received in step S210 is general It is generated by the method and sent to the server 500. That is, if it is determined that the wireless channel condition is good while the data and the response are being transmitted between the wireless terminal 400 and the server 500, the received response is not performed because the division of the previously received data has not been performed. This is the case when the response to the data is first split. Therefore, the wireless terminal 400 divides the response to the data received in the step S210 according to the wireless channel situation identified in the step S220 and transmits the divided responses to the server 500 (S240).

Accordingly, the server 500 receiving the divided responses from the wireless terminal 400 confirms reception of the transmitted data. In addition, since the server 500 increases the CWND by one each time one response is received, the server 500 increases the CWND according to the number of responses received from the wireless terminal 400 in step S240. The server 500 transmits the data following the previously transmitted data in data transmission units of the increased CWND, so that the wireless terminal 400 continuously receives the data (S210).

After receiving the data, the wireless terminal 400 proceeds to step S220 to determine whether the wireless channel situation is good. If it is determined that the wireless channel condition is good, the wireless terminal 400 proceeds to step S230 to determine whether to divide the response to the data received in step S210, and proceeds to step S240 or S300 according to the determination result. . On the other hand, if it is determined that the wireless channel situation is not good in step S220, the wireless terminal 400 generates a response to the data received in step S210 in a general manner and transmits it to the server 500 (S300). . The wireless terminal 400 repeats steps S210 to S300 until data transmission from the server 500 is completed.

In the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined not only by the claims but also by the equivalents of the claims.

According to the present invention as described above, the TCP slowing occurs at the beginning of the TCP transmission by increasing the CWND faster than before by dividing the response to the data received from the server supporting TCP / IP in a good wireless environment The problem of starting can be solved. Accordingly, the TCP slow start time is reduced, thereby improving TCP starting performance.

In addition, since the data can be received faster than before, the file download speed is faster than before and web browsing is faster than before. See the graph of FIG. 8 to examine this in more detail.

FIG. 8 compares an 802.11 wireless terminal accessing a File Transfer Protocol (FTP) server using a simulator and receiving 100k bytes of data by dividing a response according to a preferred embodiment of the present invention. It is a graph.

According to a preferred embodiment of the present invention, the response is divided into two and transmitted five times to the FTP server. As shown in FIG. 8, the reception speed of the data according to the response split is 1 than that of the conventional method. You can check that the information is faster in seconds.

Claims (6)

In a method for a wireless terminal supporting TCP / IP (Transmission Control Protocol) / (Internet Protocol) to receive data from a server supporting the TCP / IP, A first step of the wireless terminal accessing the server and receiving predetermined data; A second step of transmitting, by the wireless terminal, a response (ACK: ACKnowledge) for the predetermined data into a predetermined number according to a wireless channel condition between the wireless terminal and the server and transmitting the divided data to the server; And And a third step of receiving data transmitted in increments of congestion window units from the server according to the divided response and proceeding to the first step. The method of claim 1, The situation of the wireless channel is characterized by determining through one of the RSSI (Received Signal Strength Indicator), BER (Bit Error Rate) and BLER (Block Error Rate). The method of claim 1, The number of responses divided according to the situation of the radio channel is determined by the number within the limit that network congestion does not occur. In a method for a wireless terminal supporting TCP / IP to receive data from the server supporting the TCP / IP, The wireless terminal requests to connect to the server and transmits to the server by dividing an acknowledgment (ACK: ACKnowledge) for the predetermined data received from the server into a predetermined number according to a wireless channel condition between the wireless terminal and the server. A first process of doing; And And a second process of receiving data transmitted from the server in increments of congestion windows in response to the divided response and proceeding to the first process. The method of claim 4, wherein The situation of the radio channel is characterized by grasping through one of RSSI, BER and BLER. The method of claim 4, wherein The number of responses divided according to the situation of the radio channel is determined by the number within the limit that network congestion does not occur.

Images