A Study Of Heterogeneous Wireless Networks Splitting Strategy And Performance

As an important part of the heterogeneous wireless networks, concurrenttransmission via different networks become a hot topic due to its advantages ofaggregated bandwidths and load balance. For some data hungry applications, the singlenetwork transmission may not satisfy the user’s requirement. Therefore, concurrenttransmission which can transmit via multiple networks simultaneously has beenproposed to provide a high throughput to guarantee the quality of service.This dissertation proposes a splitting scheduling algorithm based on the TCPprotocol. First, through the TCP parameters of end-to-end delay and congestion window,splitting ratio among heterogeneous networks could be dynamically calculated. Second,in order to find out the trade-off between three duplicate ACKs problem intrigued by outof order packets and truly concurrent transmission, a policy that consists ofopportunistic sechduling, time conpensation and flowlet idea are adopted at the splittingsource. So that the out of order packets could maintain at a certain controllable range,while also be able to achieve truly concurrent aggereated bandwidths. Third, areordering algorithm to avoid out-of-order packets is also presented. Finally, thecomparison and analysis between the proposed splitting algorithm and other algorithmsby OPNET are made. It turns out that the proposed splitting scheduling algorithm basedon the TCP protocol having better end-to-end throughput and delay performances thanother algorithms, and could obtain the same splitting results at the destination side evenwithout reordering algorithm.