Tài liệu Sổ tay của các mạng không dây và điện toán di động P12 doc

... in many countries digital broadcasting systems will mostly replace cur-rent FM radio and television technology in the course of the next one or two decades. Thedigital media not only offer ... so-called candidate lists. In our algorithmic con-text, we have a priority level set on the candidate lists such that the candidate listKj(B) is of higher priority than all the candidate lists ... the DAB technology motivate the problem discussed in this chapter:First, a DAB frequency block usually carries several different radio programs and addition-al data services. Therefore we have...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P4 doc

... Unit Disk GraphsUnit disk graphs are intersection graphs of equal sized disks in the plane. It is easy to seethat given the distance model, multicoloring is equivalent to coloring for unit disk ... disk graph is the intersection graph of disks of equal diameter inthe plane. They can also be described in terms of distance or proximity models, whichconsist of a value d Ն 0 and an embedding ... of theFPA strategy discussed earlier has a performance ratio of k/2. In what follows, we discusssome specific classes of graphs that have been studied in the context of radio channel as-signment....

Tài liệu Sổ tay của các mạng không dây và điện toán di động P5 docx

... one, which indicatesthat channels assigned to the corresponding cells must be distinct, is often referred to as acochannel constraint. An intersite constraint of two, which codifies the requirement ... node or to dif-ferent nodes. More precisely, cirepresents the constraint between nodes at graph distance ifrom each other. The reuse distance of G equals k + 1, the minimum graph distance be-tween ... and P. Spirakis, Frequency assignment in mobile and radionetworks, in Proceedings of the Workshop on Networks in Distributed Computing, DIMACS Se-ries. AMS, 1998. 11. D. A. Fotakis and P....

Tài liệu Sổ tay của các mạng không dây và điện toán di động P10 doc

... thischapter, we focus on single-channel, single-hop radio networks. Single-hop radio networksare the basic ingredients from which larger, multi-hop radio networks are built [3, 22].As customary, time ... least 1 – 1/f for any fՆ 1. 10.6 CONCLUDING REMARKS AND OPEN PROBLEMSA radio network is a distributed system with no central arbiter, consisting of n radio trans-ceivers, referred to as stations. ... activity.We noted that by extending the leader election protocols for single-hop radio networksdiscussed in this chapter, one can obtain clustering protocols for multihop radio networks,in which every...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P13 docx

... [9].Although the impact of wireless networks can be studied along the different dimensions289Handbook of Wireless Networks and Mobile Computing, Edited by Ivan Stojmenovic´Copyright © 2002 John ... Service differentiation through end-to-endrate control in low bandwidth wireless packet networks, in Proceedings of IEEE InternationalWorkshop on Mobile Multimedia Communications, San Diego, ... increases, the difference in WTCP’s performance in comparison with regular TCPkeeps increasing.13.4.4 Comparative DiscussionIn order to provide intuition as to how the above-discussed approaches...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P17 docx

... blindflooding (flooding in a MANET is unwise according to [19]). One guideline is: the tighterthe QoS requirements are, the more tickets we should issue. Each probe, on reaching anyintermediate ... are discussed in [35].17.2.1 Proactive Protocols One representative proactive protocol is the destination-sequenced distance vector routing(DSDV) protocol. It is based on the traditional distance ... an intermediate node should register the ROUTE_REQ it has re-ceived to discard duplicate ROUTE_REQs.Route Discovery of SSA. The signal stability adaptive protocol (SSA) [9] tries to dis-cover...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P18 docx

... in addition guarantee that messagesarrive at their destination. Our approach differs from similar algorithms studied in the lit-393Handbook of Wireless Networks and Mobile Computing, Edited ... [27] also studied a hybrid single path/flooding algorithm thatguarantees delivery of a message. 18.3 DELAUNAY TRIANGULATIONSA common approach in serial network design is that of finding good ... communication networks [4, 26, 8]. In case direct communica-tion is not possible, it is still possible to run a distributed setup procedure to calculateDel(pi) by forwarding the position of all the nodes...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P19 doc

... ΑnʦSbdiscardctl+ ΑnʦDbdiscardctl+ ΑnʦS(mdiscard· size + bdiscard) + ΑnʦDbdiscardctl(19.1)where bdiscardctldenotes the cost for discarding a control packet; bdiscarddenotes ... until the destination node is reached, if possible.The second term can be modified to compensate for different network conditions. A vari-ation, power cost 2, minimizes pc(B, A) = f (A)[u(r) + v(s)], ... of iterations until the first node dies. The simulations are run for 20graphs for different network sizes and for HCB models [8].Both cost functions and the different power-cost methods give...

Tài liệu Sổ tay của các mạng không dây và điện toán di động P20 doc

... protocols assume bidirectional links. Prakash [27] studied the impact of unidirec-tional links on some of the existing distance vector routing protocols such as destination-sequenced distance vector ... forwarding the packet belong to dif-ferent superclusters, then forwarding will be done via an intersupercluster route; if theybelong to the same supercluster but to different clusters, forwarding ... respectively. A bidirectionaledge (v, u) can be considered as two unidirectional edges vu and uv. Arrow dashed linescorrespond to unidirectional edges and solid lines represent bidirectional edges....

Tài liệu Sổ tay của các mạng không dây và điện toán di động P23 doc

... describe two distinct on-demand multicast proto-cols currently proposed for standardization to the IETF before results of performancestudies are discussed. 23.6.1 Multicast Ad Hoc On-Demand Distance ... thisapproach suffers from the periodic data flooding overhead incurred by the source in orderto reestablish any new or lost connections. This periodic flooding causes considerabletransmission ... classic flooding method. Their paperproposes the use of self-pruning and dominant pruning to reduce the flooding cost by uti-lizing neighborhood information. Self-pruning uses direct neighbor...

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