EE 228 a - Lecture 15 - Spring 2006 Transport in Ad Hoc

There have been an exploding number of wireless application ideas, such as sensor networks. Wireless networks present unique challenges to the designers. For example, wireless channels are intrinsically unreliable due to multi-path fading. Another constraint is limited spectrum resource. Various approaches have been proposed to build scalable efficient wireless networks. Cross layer design seeks to optimize design objectives by looking at multiple network layers jointly. However, it tends to yield application specific solutions. Multi-hop approach seeks efficient routing with benefits such as reduced power consumption. The project studies the file transfer problem based on the following assumptions. • A linear multi-hop network is considered. As illustrated in Fig. 1, there are n+ 1 stationary nodes. Node 0 wants to transfer a file to Node n via n hops; intermediate nodes do not have their own traffic. • Time is discrete. • Links are unreliable with binary on and off states (two link models described later). • If a link is on, the source of that link can transfer 1 packet to the sink of that link perfectly in one time step. • Node processing delay and link propagation delay are ignored. • File size is m packets. Let T be the time taken to transfer the file. The objective to calculate the expectation of T with following link models and protocols.