A high-speed reliable data transfer method based on FPGA hardware acknowledgement

Abstract

In wired data transfer network, Transmission Control Protocol (TCP) is widely used to ensure the reliability of transmission. But the protocol requires much CPU resource and has a low transmission efficiency [1]. TCP uses retransmission when time out and data acknowledge mechanism to achieve the ability of reliable transmission [2]. Data receiver must acknowledge data frames with acknowledgement (ACK) frames to inform data transmitter that frames have been received correctly. Data transmitter can only transmit new data frames after receiving the ACK frame of current data frame, otherwise a retransmission will be started when time out. The readout and handling of ACK frames are usually accomplished by CPU, which require CPU resources and add time delay, therefore increases average ACK frame waiting time and decrease the data rate. This paper implements a high-speed reliable data transfer method based on FPGA hardware acknowledgement. This method uses acknowledgement (ACK) frames and retransmission to ensure a reliable and sequential transmission as TCP does. To overcome the disadvantages of TCP, we use FPGA handle ACK frames automatically to improve the response speed of ACK frames. FPGA generates an ACK frame without CPU when received a correct data frame and transmits the ACK frame to data source immediately. It also checks ACK frames after sending data frames. If an error or timeout occurs during checking, FPGA informs CPU to start a retransmission, otherwise a new data frame can be transmitted. By using FPGA on handling ACK frames, our method reduces ACK frame waiting and readout time, which is helpful to increase data rate and reduce CPU occupancy. This method is suitable for multi-point sensor network, especially when data is gathered to data center in the network