| In recent years, wireless networks became progressively popular by Internet users due to its flexibility and practicality to access wired networks. TCP/IP protocol was designed to handle data reliably on virtually error free-wired networks. Its reliability and error correction control mechanism made TCP/IP the official Internet protocol.; In wired networks, congestion is the main reason for most of packet loses. Conversely, in wireless networks, these losses will arise for reasons other than congestion. For instance, fading, shadowing, signal interference, etc.; In wireless networks, TCP reacts to high rate wireless packet corruption as it would in wired networks. Therefore, the very characteristics that made TCP desirable for wired networks makes it undesirable in wireless environment. When notified of an error, TCP initiates a congestion control mechanism—the reduction in the size of the transmission window and resets its retransmission timer—then it retransmits the packets. These measures when done prematurely, results in an unnecessary reduction in link bandwidth utilization, thereby causing significant degradation in performance of the overall network in the form of poor throughput. To achieve higher throughput, TCP protocol must be modified to perform satisfactorily in error prone wireless networks.; The developed solution has been accomplished by constructing an algorithm and by modifying standard TCP, when it is running over wireless networks, to distinguish wireless error from congestion one. The modified TCP solution has been evaluated and validated by developing analytical and simulation models. Statistical inference theories were implemented for further validation.; Simulation results have demonstrated significant overall throughput network improvement in wireless networks of up to 115.46% when modified TCP is implemented. |
