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528 AD HOC NETWORKS

 

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Figure 13.49 Success ratio [imprecision rate: (a) 5 % and (b) 50 %]. (Reproduced by permission of IEEE [85].)

Comparison of the performance results shown in Figures 13.49–13.52 demonstrates advantages of the TBP. The protocol presented in this section is a brief interpretation of Ticket Based Protocol represented in Chen and Nahrstedt [85] with slightly modified terminology adjusted to that of the rest of the book. The problem of QoS routing in wireline and wireless networks has been attracting much attention in both academia and industry. For more information see References [86–88]. A comprehensive overview of the literature is given in Chen and Nahrstedt [88]. The problem will be revisited again in Chapter 21 in more detail.

DISTRIBUTED QoS ROUTING

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Figure 13.50 Messages overhead (imprecision rate: 10 %). (Reproduced by permission of IEEE [85].)

 

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Figure 13.51 Cost per established path (imprecision rate: 5 %). (Reproduced by permission of IEEE [85].)

530 AD HOC NETWORKS

 

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Figure 13.52 Cost per established path (imprecision rate: 50 %). (Reproduced by permission of IEEE [85].)

REFERENCES

[1]C.E. Perkins and P. Bhagwat, Highly dynamic destination-sequenced distance-vector routing (DSDV) for mobile computers, Comput. Commun. Rev., October 1994,

pp.234–244.

[2]J. Jubin and J. Tornow, The DARPA packet radio network protocols, Proc. IEEE, vol. 75, no. 1, 1987, pp. 21–32.

[3]E. Royer and C.K. Toh, A review of current routing protocols for ad hoc mobile wireless networks, IEEE Person. Commun., April 1999, pp. 46–54.

[4]C.-C. Chiang, Routing in clustered multihop, mobile wireless networks with fading channel, in Proc. IEEE SICON ’97, April 1997, pp. 197–211.

[5]S. Murthy and I.I. Garcia-Luna-Aceves, An efficient routing protocol for wireless networks, ACM Mobile Networks App. J., (Special Issue on Routing in Mobile Communication Networks), October 1996, pp. 183–197.

[6]A.S. Tanenbaum, Computer Networks, 3rd edn, Ch. 5, Prentice Hall: Englewood Cliffs, NJ, 1996, pp. 357–358.

[7]C.E. Perkins and E.M. Royet, Ad-hoc on-demand distance vector routing, in Proc 2nd IEEE Workshop. Mobile Comput. Technol. and Applications, Feb. 1999, pp. 90–100.

[8]D.B. Johnson and O.A. Maltz, Dynamic source routing in ad-hoc wireless networks, in Mobile Computing, L. Irnielinski and H. Korth (Eds). Kluwer: Norwell, MA, 1996,

pp.153–181.

[9]J. Broch, O.B. Johnson, and D.A. Maltz, The dynamic source routing protocol for mobile ad hoc networks, IETF Internet draft, draft-ietf manet-dsr-01.txt, December

1998 (work in progress).

REFERENCES 531

[10]V.D. Park and M.S. Corson, A highly adaptive distributed routing algorithm for mobile wireless networks, in Proc. INFOCOM ‘97, April 1997.

[11]M.S. Corson and A. Ephremides, A distributed routing algorithm for mobile wireless networks, ACM/Baltzer Wireless Networks J., vol. 1, no. 1, 1995, pp. 61–81.

[12]C.-K. Toh, A novel distributed routing protocol to support ad-hoc mobile computing, in Proc. 1996 IEEE 15th Annual Int. Phoenix Conf. Computing and Communications, March 1996, pp. 480–486.

[13]R. Dube et al., Signal stability based adaptive routing (SSA) for ad-hoc mobile networks, IEEE Person. Commun., February 1997, pp. 36–45.

[14]C.-K. Toh, Associativity-based routing for ad-hoc mobile networks, Wireless Person. Commun., vol. 4, no. 2, March 1997, pp. 1–36.

[15]S. Murthy and I.I. Garcia-Luna-Aceves, Loop-free internet routing using hierarchical routing trees, in Proc. INFOCOM ‘97, 7–11, April 1997.

[16]C-C. Chiang, M. Gerla and S. Zhang, Adaptive shared tree multicast in mobile wirelesa networks, in Proc. GLOBECOM ‘98, November 1998, pp. 1817–1822.

[17]C.E. Perkins and E.M. Royer, Ad hoc on demand distance vector (AODV) routing, IETF Internet draft, draft-ietf-manet-aodv-02.txt, November 1998 (work in progress),

[18]L. Ji and M.S. Corson, A lightweight adaptive multicast algorithm, in Proc. GLOBECOM ‘98, November 1998, pp. 1036–1042.

[19]C.-K. Toh and G. Sin, Implementing associativity-based routing for ad hoc mobile wireless networks, Unpublished article, March 1998.

[20]D. Baker et al., Flat vs. hierarchical network control architecture, in ARO/DARPA Workshop mobile ad-hoc Networking; www.isr.umd. edu, Mar, 1997.

[21]M. Gerla, C-C. Chiang and L. Zhang, Tree multicast strategies in mobile, multihop wireless networks, ACM/Baltzer Mobile Networks Applic. J., 1998.

[22]S. Singh, T. Woo and C.S. Raghavendra, Power-aware routing in mobile ad hoc networks, in proc. ACM/IEEE MO6’ICOM ‘98, October 1998.

[23]Y. Ko and N.H. Vaidya, Location-aided routing (LAR) in mobile ad hoc networks, in

Proc. ACM/IEEE MCIBCOM ‘98, October 1998.

[24]C.R. Sin and M. Gerla, MACNPR: an asynchronous multimedia multihop wireless network, in Proc. IEEE INFOCOM ‘97, March 1997.

[25]Z.J. Haas and M.R. Pearlman, The performance of a new routing protocol for the reconfigurable wireless networks, in Proc. ICC’98, pp. 156–160.

[26]Z.J. Haas and M.R. Pearlman, Evaluation of the ad-hoc connectivity with the reconfigurable wireless networks, in Virginia Tech’s Eighth Symp. Wireless Personal Communications, 1998, pp. 156–160.

[27]Z.J. Haas and M.R. Pearlman, The performance of query control schemes for the zone routing protocol, in Proc. SIGCOMM’98, pp. 167–177.

[28]P. Jacquet, P. Muhlethaler and A. Qayyum, Optimized link state routing protocol, IETF MANET, Internet Draft, November 1998. http://www.ietf.cnri.reston.va.us

[29]D.B. Johnson and D.A. Maltz, Dynamic source routing in ad hoc wireless networking, in Mobile Computing, T. Imielinski and H. Korth (Eds). Kluwer: Norwell, MA, 1996.

[30]J. Moy, OSPF version 2, RFC 2178, March 1997.

[31]S. Murthy and J.J. Garcia-Luna-Aceves, A routing protocol for packet radio networks, in Proc. ACM Mobile Computing and Networking Conf. (MOBICOM’95), pp. 86–94.

532 AD HOC NETWORKS

[32]An efficient routing protocol for wireless networks, MONET, vol. 1, 1986, pp. 183– 197.

[33]V.D. Park and M.S. Corson, A highly adaptive distributed routing algorithm for mobile wireless networks, in Proc. IEEE INFOCOM ’97, Kobe, pp. 1405–1413.

[34]C.E. Perkins and P. Bhagwat, Highly dynamic destination-sequenced distance-vector routing (DSDV) for mobile computers, in Proc. ACM SIGCOMM, vol. 24, no. 4, October 1994, pp. 234–244.

[35]C.E. Perkins and E.M. Royer, Ad hoc on-demand distance vector routing, in Proc. IEEE WMCSA’99, vol. 3, New Orleans, LA, 1999, pp. 90–100.

[36]J. Sharony, A mobile radio network architecture with dynamically changing topology using virtual subnets, MONET, vol. 1, 1997, pp. 75–86.

[37]P.F. Tsuchiya, The landmark hierarchy: a new hierarchy for routing in very large networks, ACM Comput. Commun. Rev., vol. 18, 1988, pp. 35–42.

[38]M.R. Pearlman and Z.J. Haas, Determining the optimal configuration for the zone routing protocol, IEEE J. Selected Areas Commun., vol. 17, no. 8, 1999, pp. 1395– 1414.

[39]C.-C. Chiang, H.-K. Wu, W. Liu and M. Gerla, Routing in clustered multihop, mobile wireless networks, in Proc. IEEE Singapore Int. Conf. Networks, 1997, pp. 197–211.

[40]M. Gerla and J. Tsai, Multicluster, mobile, multimedia radio network, ACM-Baltzer J. Wireless Networks, vol. 1, no. 3, 1995, pp. 255–265.

[41]A. Iwata, C.-C. Chiang, G. Pei, M. Gerla and T.-W. Chen, Scalable routing strategies for ad hoc wireless networks, IEEE J. Selected Areas Commun. vol. 17, no. 8, 1999, pp. 1369–1379.

[42]L. Kleinrock and K. Stevens, Fisheye: a lenslike computer display transformation, Computer Science Department, University of California, Los Angeles, CA, Technical Report, 1971.

[43]T.-W. Chen and M. Gerla, Global state routing: a new routing schemes for ad-hoc wireless networks, in Proc. IEEE ICC’98, 7–11 June 1998, pp. 171–175.

[44]N.F. Maxemchuk, Dispersity routing, in Proc. IEEE ICC ’75, June 1975, pp. 41.10– 41.13.

[45]E. Ayanoglu, C.-L. I, R.D. Gitlin and J.E. Mazo, Diversity coding for transparent selfhealing and fault-tolerant communication networks, IEEE Trans. Commun., vol. 41, 1993, pp. 1677–1686.

[46]R. Krishnan and J.A. Silvester, Choice of allocation granularity in multipath source routing schemes, in Proc. IEEE INFOCOM ’93, vol. 1, 1993, pp. 322–329.

[47]A. Banerjea, Simulation study of the capacity effects of dispersity routing for faulttolerant realtime channels, in Proc. ACM SIGCOMM’96, vol. 26, 1996, pp. 194–205.

[48]D. Sidhu, R. Nair and S. Abdallah, Finding disjoint paths in networks, in Proc. ACM SIGCOMM ’91, 1991, pp. 43–51.

[49]R. Ogier, V. Rutemburg and N. Shacham, Distributed algorithms for computing shortest pairs of disjoint paths, IEEE Trans. Inform. Theory, vol. 39, 1993, pp. 443–455.

[50]S. Murthy and J.J. Garcia-Luna-Aceves, Congestion-oriented shortest multipath routing, in Proc. IEEE INFOCOM ’96, March 1996, pp. 1028–1036.

[51]W.T. Zaumen and J.J. Garcia-Luna-Aceves, Loop-free multipath routing using generalized diffusing computations, in Proc. IEEE INFOCOM ’98, March 1998, pp. 1408– 1417.

REFERENCES 533

[52]J. Chen, P. Druschel and D. Subramanian, An efficient multipath forwarding method, in Proc. IEEE INFOCOM ’98, 1998, pp. 1418–1425.

[53]N. Taft-Plotkin, B. Bellur and R. Ogier, Quality-of-service routing using maximally disjoint paths, in Proc. 7th Int. Workshop Quality of Service (IWQoS’99), June 1999,

pp.119–128.

[54]S. Vutukury and J.J. Garcia-Luna-Aceves, An algorithm for multipath computation using distance vectors with predecessor information, in Proc. IEEE ICCCN ’99, October 1999, pp. 534–539.

[55]I. Cidon, R. Rom, and Y. Shavitt, Analysis of multi-path routing, IEEE/ACM Trans. Networking, vol. 7, 1999, pp. 885–896.

[56]A. Nasipuri and S.R. Das, On-demand multipath routing for mobile ad hoc networks, in Proc. IEEE ICCCN, October 1999, pp. 64–70.

[57]D. Johnson and D. Maltz, Dynamic source routing in ad hoc wireless networks, in Mobile Computing, T. Imielinski and H. Korth (Eds). Kluwer: Norwell, MA, 1996.

[58]V.D. Park and M.S. Corson, A highly adaptive distributed routing algorithm for mobile wireless networks, in Proc. IEEE INFOCOM ’99, 1999, pp. 1405–1413.

[59]J. Raju and J.J. Garcia-Luna-Aceves, A new approach to on-demand loop-free multipath routing, in Proc. IEEE ICCCN, October 1999, pp. 522–527.

[60]S.J. Lee and M. Gerla, AODV-BR: backup routing in ad hoc networks, in Proc. IEEE WCNC, 2000, pp. 1311–1316.

[61]C.E. Perkins and E.M. Royer, Ad-hoc on-demand distance vector routing, in Proc. IEEE WMCSA, New Orleans, LA, February 1999, pp. 90–100.

[62]L. Wang, L. Zhang, Y. Shu and M. Dong, Multipath source routing in wireless ad hoc networks, in Proc. Canadian Conf. Electrical and Computer Engineering, vol. 1, 2000, pp. 479–483.

[63]S.J. Lee and M. Gerla, Split multipath routing with maximally disjoint paths in ad hoc networks, in Proc. ICC 2001, vol. 10, June 2001, pp. 3201–3205.

[64]P. Papadimitratos, Z.J. Haas and E.G. Sirer, Path set selection in mobile ad hoc networks, in Proc. ACM MobiHOC 2002, Lausanne, 9–11, June 2002, pp. 160–170.

[65]M.R. Pearlman, Z.J. Haas, P. Sholander and S.S. Tabrizi, On the impact of alternate path routing for load balancing in mobile ad hoc networks, in Proc. MobiHOC, 2000,

pp.150–310.

[66]N. Gogate, D. Chung, S. Panwar and Y. Wang, Supporting video/image applications in a mobile multihop radio environment using route diversity, in Proc. IEEE ICC ’99, vol. 3, June 1999, pp. 1701–1706.

[67]A. Tsirigos and Z.J. Haas, Analysis of Multipath Routing: part 2 – mitigation of the effects of frequently changing network topologies, IEEE Trans. Wireless Commun., vol. 3, No. 2, March 2004, pp. 500–511.

[68]A.B. McDonald and T. Znati, A path availability model for wireless ad hoc networks, in Proc. IEEE WCNC, vol. 1, 1999, pp. 35–40.

[69]A. Tsirigos and Z.J. Haas, Analysis of multipath routing: part 1 – the effect on packet delivery ratio, IEEE Trans. Wireless Commun., vol. 3, no. 1, 2004, pp. 138–146.

[70]C.R. Lin and M. Gerla, Adaptive clustering for mobile wireless networks,”IEEE J. Selected Areas Commun., vol. 15, no. 7, 1997, pp. 1265–1275.

[71]M. Gerla and J.T. Tsai, Multicluster, mobile, multimedia radio network, Wireless Networks, vol. 1, 1995, pp. 255–265.

534 AD HOC NETWORKS

[72]N.H. Vaidya, P. Krishna, M. Chatterjee and D.K. Pradhan, A cluster-based approach for routing in dynamic networks, ACM Comput. Commun. Rev., vol. 27, no. 2, 1997.

[73]R. Ramanathan and M. Steenstrup, Hierarchically-organized, multihop mobile wireless networks for quality-of-service support, Mobile Networks Applic., vol. 3, no. 1, 1998, pp. 101–119.

[74]A.B. McDonald and T.F. Znati, A Mobility-based framework for adaptive clustering in wireless ad hoc Networks, IEEE J. Selected Areas Commun., vol. 17, No. 8, 1999,

pp.1466–1488.

[75]D.J. Baker and A. Ephremides, The architectural organization of a mobile radio network via a distributed algorithm, IEEE Trans. Commun., 1981, pp. 1694–1701.

[76]D.J. Baker, J. Wieselthier and A. Ephremides, A distributed algorithm for scheduling the activation of links in a self-organizing, mobile, radio network, in Proc. IEEE ICC’82, pp. 2F.6.1–2F.6.5.

[77]I. Chlamtac and S.S. Pinter, Distributed nodes organization algorithm for channel access in a multihop dynamic radio network, IEEE Trans. Comput., 1987, pp. 728– 737.

[78]M. Gerla and J. T.-C. Tsai, Multicluster, mobile, multimedia radio network, ACMBaltzer J. Wireless Networks, vol. 1, no. 3, 1995, pp. 255–265.

[79]A.B. McDonald and T. Znati, Performance evaluation of neighbour greeting protocols: ARP versus ES-IS, Comput. J., vol. 39, no. 10, 1996, pp. 854–867.

[80]P. Beckmann, Probability in Communication Engineering. Harcourt Brace World: New York, 1967.

[81]Y. Hu and D.B. Johnson, Caching strategies in on-demand routing protocols for wireless ad hoc networks, in Proc. MobiCom 2000, August 2000, pp. 231–242.

[82]D.B. Johnson and D.A. Maltz, Dynamic source routing in ad hoc wireless networks, www.ietf.org/internet-drafts/ draft-ietf-manet-dsr-03.txt, IETF Internet Draft (work in progress), October 1999.

[83]M.K. Marina and S.R. Das, Performance of route cache strategies in dynamic source routing: Proc. Second Wireless Networking and Mobile Computing (WNMC), April 2001.

[84]D. Maltz, J. Broch, J. Jetcheva and D.B. Johnson, The effects of on-demand behavior in routing protocols for multi-hop wireless ad hoc networks, IEEE J. Selected Areas in Commun., Special Issue on Mobile and Wireless Networks, August 1999.

[85]S. Chen and K. Nahrstedt, Distributed quality-of-service routing in ad hoc Networks, IEEE J. Selected Areas Commun., vol. 17, no. 8, August 1999, pp. 1488–1505.

[86]H.F. Soloma, S. Reeves and Y. Viniotis, Evaluation of multicast routing algorithms for real-time communication on high-speed networks, IEEE J. Selected Area Commun. vol. 15, no. 3, 1997, pp. 332–345.

[87]I. Cidon, R. Ram and V. Shavitt, Multi-path routing combined with resource reservation,: IEEE INFOCOM ‘97, Japan, April 1997, pp. 92–100.

[88]S. Chen and K. Nahrstedt, An overview of quality-of-service routing for the next generation high-speed networks: problems and solutions, IEEE Networks, Special Issue on Transmission and Distribution of Digital Video, November/December 1998,

pp.64–79.

14

Sensor Networks

14.1 INTRODUCTION

A sensor network is composed of a large number of sensor nodes, which are densely deployed either inside the phenomenon they are observing, or very close to it. Most of the time the nodes are randomly deployed in inaccessible terrains or disaster relief operations. This also means that sensor network protocols and algorithms must possess self-organizing capabilities. Another unique feature of sensor networks is the cooperative effort of sensor nodes. Sensor nodes are fitted with an on-board processor. Instead of sending the raw data to the nodes responsible for the fusion, sensor nodes use their processing abilities to locally carry out simple computations and transmit only the required and partially processed data.

The above described features ensure a wide range of applications for sensor networks. Some of the application areas are health, military and security. For example, the physiological data about a patient can be monitored remotely by a doctor. While this is more convenient for the patient, it also allows the doctor to better understand the patient’s current condition. Sensor networks can also be used to detect foreign chemical agents in the air and the water. They can help to identify the type, concentration and location of pollutants. In essence, sensor networks will provide the end user with intelligence and a better understanding of the environment. It is expected that, in future, wireless sensor networks will be an integral part of our lives, even more than the present-day personal computers.

Realization of these and other sensor network applications require wireless ad hoc networking techniques. Although many protocols and algorithms have been proposed for traditional wireless ad hoc networks, as described in Chapter 13, they are not well suited for the unique features and application requirements of sensor networks. To illustrate this point, the differences between sensor networks and ad hoc networks (see Chapter 13, and

Advanced Wireless Networks: 4G Technologies Savo G. Glisic

C 2006 John Wiley & Sons, Ltd.

536 SENSOR NETWORKS

references therein) are outlined below [1–5]:

sensor nodes are densely deployed;

sensor nodes are prone to failure;

the number of sensor nodes in a sensor network can be several orders of magnitude higher than the nodes in an ad hoc network;

the topology of a sensor network changes very frequently;

sensor nodes mainly use broadcast communication paradigms whereas most ad hoc networks are based on point-to-point communications;

sensor nodes are limited in power, computational capacities and memory;

sensor nodes may not have global identification (ID) because of the large amount of overhead and large number of sensors.

One of the most important constraints on sensor nodes is the low power consumption requirement. Sensor nodes carry limited, quite often irreplaceable, power sources. Therefore, while traditional networks aim to achieve high QoS provisions, sensor network protocols must focus primarily on power conservation. They must have inbuilt trade-off mechanisms that give the end user the option of prolonging network lifetime at the cost of lower throughput or higher transmission delay. This problem will be the focus of this chapter.

Sensor networks may consist of many different types of sensors such as seismic, low sampling rate magnetic, thermal, visual, infrared, acoustic and radar. These sensors are able to monitor a wide variety of ambient conditions that include the current characteristics such as speed, direction and size of an object, temperature, humidity, vehicular movement, lightning condition, pressure, soil makeup, noise levels, the presence or absence of certain kinds of objects, mechanical stress levels on attached objects etc.

Sensor nodes can be used for continuous sensing, event detection, event ID, location sensing, and local control of actuators. The concept of micro-sensing and wireless connection of these nodes promises many new application areas. Usually these applications are categorized into military, environment, health, home and other commercial areas. It is possible to expand this classification with more categories such as space exploration, chemical processing and disaster relief.

Wireless sensor networks can be an integral part of military command, control, communications, computing, intelligence, surveillance, reconnaissance and targeting (C4ISRT) systems. They are used for monitoring friendly forces, equipment and ammunition and battlefield surveillance (Figure 14.1). Sensor networks can be deployed in critical terrains, and some valuable, detailed and timely intelligence about the opposing forces and terrain can be gathered within minutes before the opposing forces can intercept them. Sensor networks can also be incorporated into the guidance systems of intelligent ammunition.

Sensor networks deployed in the friendly region and used as a chemical or biological warning system can provide friendly forces with critical reaction time, which decreases casualty numbers drastically. Environmental applications of sensor networks include tracking the movements of birds, small animals and insects; monitoring environmental conditions that affect crops and livestock; irrigation; macroinstruments for large-scale Earth monitoring and planetary exploration; chemical/biological detection; precision agriculture; biological, Earth and environmental monitoring in marine, soil and atmospheric contexts; forest fire

 

 

SENSOR NETWORKS PARAMETERS

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Figure 14.1 Battlefield surveillance.

detection; meteorological or geophysical research; flood detection; bio-complexity mapping of the environment; and pollution study.

The health applications for sensor networks are providing interfaces for the disabled, integrated patient monitoring, diagnostics, drug administration in hospitals, monitoring the movements and internal processes of insects or other small animals, telemonitoring of human physiological data, and tracking and monitoring doctors and patients inside a hospital. More details on sensor networks applications can be found in References [6–64].

14.2 SENSOR NETWORKS PARAMETERS

A sensor network design is influenced by many parameters, which include fault tolerance, scalability, production costs, operating environment, sensor network topology, hardware constraints, transmission media and power consumption. The failure of sensor nodes should not affect the overall task of the sensor network. This is the reliability or fault tolerance issue. Fault tolerance is the ability to sustain sensor network functionalities without any interruption due to sensor node failures [25, 49].

The protocols and algorithms may be designed to address the level of fault tolerance required by the sensor networks. If the environment where the sensor nodes are deployed has little interference, then the protocols can be more relaxed. For example, if sensor nodes are being deployed in a house to keep track of humidity and temperature levels, the fault tolerance requirement may be low since this kind of sensor networks is not easily damaged or interfered with by environmental noise. On the other hand, if sensor nodes are being deployed in a battlefield for surveillance and detection, then the fault tolerance has to be high because the sensed data are critical and sensor nodes can be destroyed by hostile actions. As a result, the fault tolerance level depends on the application of the sensor networks, and