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... Usually, the hard handoff can be further divided into two different types—intra- and intercell handoffs. The soft handoff can also be divided into two different types—multiway soft handoffs and softer ... Q H is filled. In this case, we consider the case for M O = 0. The two-dimensional state-transition dia- gram becomes one-dimensional ( j = 0). Therefore, the state probabilities can easily be ... basic concept of handoff in mobile cellular radio systems has been introduced. Sever- al different traffic models have been described and briefly discussed. Four conventional handoff schemes in...

Ngày tải lên: 15/12/2013, 05:15

... the cells within a distance of D from the last reported cell. The distance-based strategy is dynamic, and the distance threshold D can be determined on a per-user basis depending on his/her mobility ... mobile station at and around its predicated location in descending probability un- til the mobile station is found. Their simulation results show that the predictive distance- based scheme performs ... reasons. First, some important distributions such as the exponential, Erlang, and Chi-square distributions are special cases of the Gamma distribution. Second, the Gamma distribution has a simple Laplace–Stieltjes...

Ngày tải lên: 15/12/2013, 05:15

... and code division can be used in order to divide the radio spectrum. In fre- quency division, the spectrum is divided into frequency bands. In time division, the us- age of the channel is divided ... growth of radio traffic, and other fac- tors. A given radio spectrum (bandwidth) dedicated for cellular communications can be divided into a set of disjoint and noninterfering radio channels. ... using different bench- marks following extended simulations with a variety of assumptions regarding the mobile radio environment. Some of these assumptions might be the cellular topology, the differ- ent...

Ngày tải lên: 15/12/2013, 05:15

... 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 ... one node of each distinct base color, except for two pairs of heavy nodes, each corresponding to a base color different from v’s and from each other; (b) at most one node of each dis- tinct base ... of the FPA strategy discussed earlier has a performance ratio of k/2. In what follows, we discuss some specific classes of graphs that have been studied in the context of radio channel as- signment....

Ngày tải lên: 15/12/2013, 05:15

... and P. Spirakis, Frequency assignment in mobile and radio networks, 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. REFERENCES 115 directly to the following bound, adapted from [12]. For any ... 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...

Ngày tải lên: 15/12/2013, 05:15

... fixed Algorithm complexity medium medium high high Communication complexity low medium high medium Channel utilization medium high medium high Control overhead medium high high medium 20. I. Chlamtac ... broadcast problem in mobile radio net- works, Distributed Computing 10, 3, 129–135, April 1997. 26. I. Cidon and M. Sidi, Distributed assignment algorithms for multihop packet radio networks, IEEE Trans. ... Time division duplexing (TDD) alternates transmission and reception at different time instants on the same frequency band, whereas frequency division duplexing (FDD) separates the two into different...

Ngày tải lên: 24/12/2013, 13:16

... focus on the radio interface adopted in the TD-CDMA system. This in- terface is named UMTS terrestrial radio access—time division duplex (UTRA-TDD). To support data connections with different bit ... to in- dicate readiness to receive the data. This mechanism can be used to capture the channel con- trol before the transmission of long packets, thus avoiding “long collisions.” In addition, ... transmitting. If the medium is found to be idle for an interval that exceeds the distributed interframe space (DIFS), the station continues with its transmission.* On the other hand (when the medium is busy),...

Ngày tải lên: 24/12/2013, 13:16

... prediction model is used to determine whether a flow perceives a clean or dirty channel during each slot. (If the channel is dirty, we assume that the channel prediction model can also predict ... receive additional service only when leading flows relinquish slots. As a consequence of its compensation model, CIF-Q provides a graceful linear degra- dation in service for leading flows. Additionally, ... a leading flow denotes the amount of additional service that the flow has to relinquish in the future in order to compensate for additional service received in the past. There are two distinct...

Ngày tải lên: 24/12/2013, 13:16

... accordingly the value of its prefix sum. In one additional time slot, station S k reveals its identity. The reader should have no difficulty confirming that when the protocol terminates, conditions ... set N ǟ N + 1 endif all stations set L ǟ L – 1 endif endwhile 204 RANDOMIZED INITIALIZATION PROTOCOLS FOR RADIO NETWORKS Figure 9.1 Illustrating a partition tree. 13. J. L. Bordim, J.Cui, T. ... Fifer and F. J. Bruno, Low cost packet radio, Proceedings of the IEEE, 75, 33–42, 1987. 20. M. Gerla and T C. Tsai, Multicluster, mobile, multimedia radio network, Wireless Networks, 1, 255–265,...

Ngày tải lên: 24/12/2013, 13:16

... 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 as stations. ... activity. We noted that by extending the leader election protocols for single-hop radio networks discussed in this chapter, one can obtain clustering protocols for multihop radio networks, in which every...

Ngày tải lên: 24/12/2013, 13:16

... the same disk. Data items are then selected from the disks for broadcast according to the relative broadcast frequencies assigned to the disks. This is achieved by further dividing each disk into ... [38]. 11.2.1.3 Broadcast Disks A hierarchical dissemination architecture, called broadcast disk (Bdisk), was introduced in [1]. Data items are assigned to different logical disks so that data items ... relative broadcast frequencies of the disks. Conceptually, the disks can be conceived as real physical disks spinning at different speeds, with the faster disks placing more instances of their...

Ngày tải lên: 24/12/2013, 13:16

... that point to additional directions for future research. We sketch out some of these in the following. More details can be found in [10]. 286 ENSEMBLE PLANNING FOR DIGITAL AUDIO BROADCASTING TABLE ... 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 ... 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...

Ngày tải lên: 24/12/2013, 13:16

... 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, ... [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 ... increases, the difference in WTCP’s performance in comparison with regular TCP keeps increasing. 13.4.4 Comparative Discussion In order to provide intuition as to how the above-discussed approaches...

Ngày tải lên: 24/12/2013, 13:16

... approximate them to the average distance among all training data, (ii) calculate the dis- tances among the centers in each dimension and use some percentage of this distance for the scale factor ... the prop- er distribution of some keys that allow the creation of unforgeable credentials. Thus, de- signing secure key distribution in ad hoc networks is a challenging problem. Diffie–Hell- man ... Mobile Radio Communication, 1996, pp. 1239–1242. 16. T. Lunt et al., Knowledge-Based Intrusion Detection, in Proceedings AI Systems in Government Conference, 1986. 17. T. Lunt, Automated audit trail...

Ngày tải lên: 24/12/2013, 13:16

... broadcast medium at the LLC layer. A so-called distribution system handles the pack- et forwarding toward destination devices outside the cell across the wired network infra- structure. The distribution ... Ad Hoc Networking, Reading, MA: Addison-Wesley, 2000. 55. J. Rabaey, P. Wright, and B. Brodersen, The Pico radio project: http://www.eecs.berkeley.edu/ Research/Pico_Radio. 56. Report to the ... this band, 79 different radio fre- quency (RF) channels spaced 1 MHz apart are defined. The baseband and the Bluetooth radio layers compose the Bluetooth core protocols. Bluetooth radio provides...

Ngày tải lên: 24/12/2013, 13:16

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Ngày tải lên: 21/01/2014, 19:20

Ngày tải lên: 21/01/2014, 19:20

Ngày tải lên: 21/01/2014, 19:20