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Explore the impact of Cross-Layer Design on wireless networks, addressing congestion and packet loss issues for improved TCP throughput in mobile computing environments. Future studies focus on congestion error detection.
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Future Internet - Cross Layer Design for Wireless Mobile Network - Data & Knowledge Engineering Lab. Hye-Won Cho.
Introduction (A) • Important changes in wireless networks • The expansion of accessible area of the wireless • The increasing need of the mobile computing • The need of wireless-only protocol architecture • Current standard protocol(e.g, TCP/IP) is inefficient in wireless networks • EX) when a packet loss occurs, • in wired networks caused by congestion in the network • in wireless networks caused not only by congestion but also by poor wireless channel conditions and disconnections. • But TCP is unaware of these channel conditions, it invokes its • standard algorithm and reduces its throughput. • Especially it’s important in mobile computing. • Also it has to consider compatibility with other types of protocols • Apply a Cross-Layer Approach to the standard protocol ! (B)
Idea (1/2) • Cross-Layer Design • introduced in 2005 ~ • Basic idea : ‘Cross-Layer Feedback’ • means enabling interaction of a layer with any other layer in the protocol stack. • IDEA • “ Control congestion using Cross-Layer Approach in • wireless mobile computing “ • TCP manage packet loss occurred at the lower layer using • ‘retransmission Mechanism’. • TCP layer control this without adjusting the TCP buffer size. • But in a wireless mobile computing environment there are several reasons • that packet loss can occur • ex) wireless network congestion, media capacity(channel status), backbone network status • Without reducing the buffer size is not efficient in the case of wireless • network congestion.
Idea (2/2) • If we can detect the type of the congestion error and if we can re-transfer the packet not reducing buffer size we can get an improved performance of TCP throughput ! • Controlling the buffer size using the Cross-Layer Approach. < Retransmission control Mechanism applied in Cross-Layer Approach > • Future studies: ‘how to detect a congestion error’….
References [1] Cross-Layer Feedback Architecture for Mobile Device Protocol Stacks [2] Cross-Layer Design: A Survey and the Road Ahead [3] 이동 컴퓨팅 기반 기술 (http://rsiwin.com.ne.kr/docu/DATA/prom-6-1.htm Thanks~!