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 ... 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. ... onenode of each distinct base color, except for two pairs of heavy nodes, each correspondingto a base color different from v’s and from each other; (b) at most one node of each dis-tinct base...

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

... 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. ... 15. J. R. Griggs and R. K. Yeh, Labeling graphs with a condition at distance 2, SIAM J. Discr. Math.,5: 586–595, 1992. REFERENCES115directly to the following bound, adapted from [12]. For any ... 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...

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 P12 doc

... that point to additionaldirections for future research. We sketch out some of these in the following. More detailscan be found in [10].286ENSEMBLE PLANNING FOR DIGITAL AUDIO BROADCASTINGTABLE ... 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 ... 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...

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

... Service differentiation through end-to-endrate control in low bandwidth wireless packet networks, in Proceedings of IEEE InternationalWorkshop on Mobile Multimedia Communications, San Diego, ... [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 ... 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 ... similar problems are studied. Shortest-path problems are studied in which amap is not known in advance. They seek dynamic decision rules that optimize the worst-case ratio of the distance covered ... the set of edges chosen individually by thenodes of the network form a planar graph. The necessity for the second condition follows from our desire to have fully distributedprotocols that...

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 ... risk of collisions. An expanding ring search, in which a sequence of hop-count-limitedroute discoveries limits the route request messages dispersed, is also used.The results also ... bdiscardctldenotes the cost for discarding a control packet; bdiscarddenotes the cost fordiscarding a data packet, including the cost associated with entering a reduced energystate during data transmission;...

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

... 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 ... 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 ... destination-sequenced distance-vector routing(DSDV) for mobile computers, Proceedings of ACM SIGCOMM’94, p. 234, 1994.27. R. Prakash, Unidirectional links prove costly in wireless ad hoc networks, Proceedings...

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 ... tree. The intermediate routers in the tree are responsible for for-warding the multicast data to members. In this manner, all receivers join the multicastgroup by explicitly sending a JOIN message...

Xem thêm