The disclosure discloses a Software Defined Radio (SDR)-based radio communication transmission system. A front-end analog interface unit, a Digital-to-Analog (D/A) and Analog-to-Digital (A/D) conversion unit, a core processing unit and a storage unit adopt the universal bus for interconnection and interworking. The core processing unit is configured to acquire the front-end processed data from the front-end analog interface unit, and to choose to transmit the front-end processed data to the D/A and A/D conversion unit by the control of the universal bus according to whether the radio communication standard of the current data accords with the current working mode. The disclosure further discloses an SDR-based radio communication transmission method, which includes that: the core processing unit chooses to transmit the front-end processed data to the D/A and A/D conversion unit by the control of the universal bus according to whether the radio communication standard of the current data accords with the current working mode. The system and method of the disclosure can adapt to the coexistence of multiple radio communication standards and complement the advantages of each structure at the same time.
Guangdong Sheng (China) -- History. and Deng, Xiaoping, 1904-1997 -- Travel -- China -- Guangdong Sheng.
Ben shu zuo zhe yi Xin hua she zi shen ji zhe de shen fen xin li le zhe duan li shi, shi hou, you dui xiang guan dang shi ren jin xing le shen ru de fang tan, yi qi hui hong er xi ni de bu chu, zai xian le Deng Xiaoping nan xing de quan guo cheng he zhu duo xi jie.
Wang, Ruhai, Horan, Stephen, Tian, Bingxin, and Bonasu, Sreelakshmi
IEEE Transactions on Aerospace and Electronic Systems. Oct 2006, Vol. 42 Issue 4, p1311, 12 p.
TCP/IP, Regression analysis -- Analysis, and Transmission Control Protocol/Internet Protocol (Computer network protocol) -- Analysis
The acknowledgement (ACK) strategy of transmission control protocol (TCP) has been modified to delay the ACKs for a configurable period of time that is related to the round-trip time (RTT) to improve its performance in asymmetric links such as space communications. A general relationship between the asymmetric channel ratio and the optimal ACK frequency to achieve maximum throughput is not available. This paper studies the optimal ACK frequency with respect to the channel RTT to achieve the maximum throughput over various asymmetric, geo-stationary Earth orbit (GEO)-satellite links using a test-bed. We found that when the asymmetric channel ratio is as high as about 100/1, the optimal ACK frequency must be increased with an increase in asymmetric ratio to complement the impact of the reduction of ACK channel rate. As a rule of thumb, every two-fold increase in asymmetric ratio requires the optimal ACK frequency to be increased by one ACK per RTT. A regression model was built to reflect the relationship between the optimal ACK frequency and the asymmetric channel ratio and has been validated.