Tài liệu Sổ tay của các mạng không dây và điện toán di động P28 doc

... wireless environments are transmis- sion media like infrared or radio frequency; channel coding schemes like TDMA, CDMA, etc., and spreading techniques like direct spread, frequency hopping, etc. ... protocols, the channel encoding scheme and physical medium are orthogonal issues. 28.2.1 Transmission Medium The choice of transmission media [4], namely infrared or radio frequency, is one of ....

Ngày tải lên: 26/01/2014, 15:20

... Unit Disk Graphs Unit disk graphs are intersection graphs of equal sized disks in the plane. It is easy to see that given the distance model, multicoloring is equivalent to coloring for unit disk ... disk graph is the intersection graph of disks of equal diameter in the plane. They can also be described in terms of distance or proximity models, which consist of a value d Ն 0 and an embedding...

Ngày tải lên: 15/12/2013, 05:15

... one, which indicates that channels assigned to the corresponding cells must be distinct, is often referred to as a cochannel constraint. An intersite constraint of two, which codifies the requirement ... node or to dif- ferent nodes. More precisely, c i represents the constraint between nodes at graph distance i from each other. The reuse distance of G equals k + 1, the minimum graph distance...

Ngày tải lên: 15/12/2013, 05:15

... this chapter, we focus on single-channel, single-hop radio networks. Single-hop radio networks are the basic ingredients from which larger, multi-hop radio networks are built [3, 22]. As customary, time ... least 1 – 1/f for any f Ն 1. 10.6 CONCLUDING REMARKS AND OPEN PROBLEMS A radio network is a distributed system with no central arbiter, consisting of n radio trans- ceivers, referred to a...

Ngày tải lên: 24/12/2013, 13:16

... 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. The digital 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 list K j (B) is of higher priority than all the candidate lists ......

Ngày tải lên: 24/12/2013, 13:16

... [9]. Although the impact of wireless networks can be studied along the different dimensions 289 Handbook of Wireless Networks and Mobile Computing, Edited by Ivan Stojmenovic´ Copyright © 2002 John ... Service differentiation through end-to-end rate control in low bandwidth wireless packet networks, in Proceedings of IEEE International Workshop on Mobile Multimedia Communications, San Diego,...

Ngày tải lên: 24/12/2013, 13:16

... blind flooding (flooding in a MANET is unwise according to [19]). One guideline is: the tighter the QoS requirements are, the more tickets we should issue. Each probe, on reaching any intermediate ... 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 dist...

Ngày tải lên: 21/01/2014, 19:20

... in addition guarantee that messages arrive at their destination. Our approach differs from similar algorithms studied in the lit- 393 Handbook of Wireless Networks and Mobile Computing, Edited ... [27] also studied a hybrid single path/flooding algorithm that guarantees delivery of a message. 18.3 DELAUNAY TRIANGULATIONS A common approach in serial network design is that of finding good ......

Ngày tải lên: 21/01/2014, 19:20

... Α nʦS b discardctl + Α nʦD b discardctl + Α nʦS (m discard · size + b discard ) + Α nʦD b discardctl (19.1) where b discardctl denotes the cost for discarding a control packet; b discard denotes ... 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)...

Ngày tải lên: 21/01/2014, 19:20

... 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 they belong to the same supercluster but to different clusters, for...

Ngày tải lên: 21/01/2014, 19:20