Radio packet data transmission control system and method
View Patent ↗A system and method for controlling transmission of a radio packet data are disclosed. A time point when a congestion controlling mechanism, causing a TCP performance degradation with the mobile station and the PDSN, is previously detected, and when the mechanism is operated, it is quickly returned. Thus, in spite of a bit error (data loss) existing due to the characteristics of the radio data service, a reliable data service can be guaranteed.
1. A method for controlling radio packet data transmission in a wireless system in which packet data is transmitted by using a transmission control protocol (TCP), comprising:
transmitting a packet data from a fixed station to a mobile station;
checking whether a TCP congestion controlling is performed on the basis of a number of retransmission requests by the mobile station and a data rate change, wherein the checking comprises:
checking a bit error possibility by counting the number of retransmission requests from the mobile station on a same sequence for a predetermined time,
measuring a current data rate if there is a bit error possibility, and
checking whether the TCP congestion controlling is performed by comparing the measured data rate with a reference rate; and
automatically re-transmitting a packet data when the TCP congestion controlling is performed.
2. The method of claim 1 , wherein the number of re-transmission requests is a number for a same sequence.
3. The method of claim 1 , wherein the packet data re-transmission is made from the fixed station irrespective of the retransmission requests by the mobile station.
4. The method of claim 1 , wherein the fixed station is a base station.
5. The method of claim 1 , wherein the packet data is a radio link protocol data.
6. The method of claim 5 , wherein if the current data rate is smaller than the reference rate, it is determined that the TCP congestion controlling is being performed.
7. The method of claim 5 , further comprising:
stopping a monitoring activity if it is determined that the TCP congestion controlling is not being performed.
8. The method of claim 5 , further comprising:
transmitting a virtual signal to the mobile station and an upper server in order to stop a congestion controlling if the TCP congestion controlling is being performed.
9. The method of claim 8 , wherein the virtual signal is transmitted through an Internet control message protocol (ICMP).
10. A method for controlling radio packet data transmission in a wireless system in which packet data is transmitted by using a transmission control protocol (TCP), comprising:
transmitting packet data from a fixed station to a mobile station;
determining whether there is a bit error possibility by counting re-transmission requests received from the mobile station;
determining whether a TCP congestion controlling is being performed by checking a current data rate if there is a bit error possibility; and
automatically re-transmitting packet data to the mobile station if it is determined that the TCP congestion controlling is being performed.
11. The method of claim 10 , wherein if the current data rate is smaller than a reference rate, determining that the TCP congestion controlling is being performed.
12. The method of claim 10 , wherein the packet data re-transmission is automatically made irrespective of the retransmission requests from the mobile station.
13. The method of claim 10 , wherein if it is determined that the TCP congestion controlling is being performed, transmitting packet Internet grouper (PING) data to the mobile station from the fixed station.
14. A system for controlling radio packet data transmission in a wireless system in which packet data is transmitted by using a transmission control protocol (TCP), comprising:
data receiving unit for receiving packet data from a packet serving node;
a controller for storing the received data and transmitting it to a lower layer, and controlling a TCP congestion control mechanism on the basis of a current data rate change if a bit error possibility signal is inputted; and
a radio link processing unit for processing the packet data received from the controller to transmit it to a mobile station, and counting requests for re-transmission from the mobile station and transmitting a bit error possibility signal to the controller.
15. The system of claim 14 , wherein the radio link processing unit counts the requests for re-transmission from the mobile station, and if the requests for re-transmission for a same sequence is greater than a predetermined number, the radio link processing unit transmits the bit error possibility signal to the controller.
16. The system of claim 14 , wherein the controller monitors a current data rate from a time point when the bit error possibility signal is inputted, and determines whether the TCP congestion control mechanism is operated according to a change in the data rate.
17. The system of claim 16 , wherein if the TCP congestion control mechanism is determined to be operated, the controller transmits a previously stored packet data to the radio link processing unit to be transmitted to the mobile station.
18. The system of claim 16 , wherein if it is determined that the TCP congestion controlling is currently being performed, the controller transmits a virtual signal to the mobile station and an upper server in order to stop the TCP congestion controlling.
19. The system of claim 18 , wherein the virtual signal is transmitted through an Internet control message protocol (ICMP).