tailieunhanh - Topology Control in Wireless Ad Hoc Networks phần 6

Các vấn đề được xem xét trong tài liệu: xác định phát sóng energyefficient đồ thị Tương tự như trường hợp của unicast, các khái niệm về yếu tố kéo dài phát sóng của một subgraph G G có thể được định nghĩa trong trường hợp này, mục tiêu là để tìm thấy thưa thớt | 5th ACM MobiHoc - Tokyo May 24 2004 The mobile CTR 3 SantiBlough02 it is shown through simulation that a relatively modest increase about 21 of the transmitting range with respect to the critical value is sufficient to ensure full connectivity in case of RWP mobility Simulation results also show that the transmitting range can be considerably reduced in the order of 35 - 40 if the requirement for connectivity is only on 90 of the network operational time giant component An analytical result Santi04 if we denote with rp the CTR with RWP mobile networks when the pause time is p 0 and vmin vmax v we have _ p v ln n V ------------------ p p n . If p 0 then r0 Sqrt ln n n . Istituto di Informatica Mobility 6 10 e Telematica 5th ACM MobiHoc - Tokyo May 24 2004 The mobile CTR 4 CTR in case of stationary and RWP mobile networks from Santi04 Remark note the threshold phenomenon for n 50 rp when p 0 is smaller than the CTR for the stationary case while when n 50 the situation is reversed Istituto di Informatica e Telematica Mobility 7 10 5th ACM MobiHoc - Tokyo May 24 2004 Non-homogeneous TC In case of non-homogeneous TC more relevant effect of mobility is the message overhead needed to maintain the desired topology Overhead depends on the frequency with which the reconfiguration procedure is executed which in turn depends on - The mobility pattern - The properties of the topology generated by the protocol Example MST-based vs. k-neighbor based TC - The message overhead needed to build the MST is much larger than that needed to build the k-neighbors graph - Given the same mobility pattern the MST should be reconfigured much more frequently than the k-neighbors graph k-neighbor based TC is more resilient to mobility than MST-based TC Istituto di Informatica e Telematica Mobility 8 .