Catálogo de publicaciones - libros

Multipath routing has been a promising technique in MANETs and WSNs. It has been shown through both theoretical analysis and simulation results that multipath routing provides many performance benefits, including improved fault tolerance, security, and reliability, improved routing efficiency and reduced routing overhead, more balanced traffic load and energy consumption, reduced end-to-end latency, and aggregated network bandwidth, etc. Significant research efforts have been made and are continuously being made in developing multipath routing protocols and multipath packet forwarding techniques in order to achieve the above-mentioned performance gains effectively and efficiently. Nevertheless, many issues that are directly related to the application of multipath routing remain untouched, such as the integration of the multipath routing into the current single-path routing paradigm, the synchronization of the packets among the multiple paths, and the interfaces of multipath routing protocols to other layers of protocol in the network protocol stack, etc.

Due to space limitations, we are only able to introduce the basic concept of multipath routing, highlight the fundamental techniques used to find the multiple paths, and outline the essential idea of what and why it can help in performance. For detailed algorithms/protocols as well as performance evaluations, interested readers are referred to respective publications.

This chapter has addressed the challenges of large-scale on-demand data broadcasts introduced by broadcast media such as satellite networks, cable networks, wireless LANs, and cellular networks. In such environments, the scheduling problem is different from that in a point-to-point communication environment or a push-based broadcast environment. Moreover, when variable-sized heterogeneous requests are considered, most of the previous scheduling algorithms fail to perform well. As stretch is widely adopted as a performance metric for variable-size data requests, we proposed a broadcast scheduling algorithm to optimize the system performance in terms of stretch. One nice property of the proposed algorithm is that it is extremely simple and the computation overhead is very low. Analytical results described the intrinsic behavior of the algorithm. Simulation results demonstrated that our algorithm significantly outperforms existing scheduling algorithms under various scenarios.

In this chapter, we classify services into three categories: Bandwidth Guaranteed (BG) service, Bandwidth Not Guaranteed (BNG) service and Best Effort (BE) service. For each of the above three categories, traffic descriptors and QoS parameters are defined and specified. We abstract the three categories into a general traffic model. Under such a general abstract traffic model, an optimal CAC scheme that guarantees the QoS parameters’ requirements and traffic descriptors, and maximizes the revenue, is presented analytically. The proposed schemes allow us to make decisions on call admission control, as well as bandwidth reallocation at the same time using the semi-Markov decision process approach. The Interior Point Method in linear programming is used to solve the optimal decision problem. With reasonable size of and , the proposed approach will fit well in the real system.

In this chapter, we have presented a different approach to solve the problems of RWA in wavelength-routed survivable optical networks. This approach solves the problems of RWA jointly by formulating the problem as a linear programming problem. Although this approach increases the number of variables required to formulate the problem, it ensures obtaining the optimum solution. The study also found that many network optimization problems can be solved using an LP solvers. However, more research is needed to investigate the problem and find out ways to ensure integer solutions using LP solver when an optimum integer solution is feasible. The following problem formulation has been performed:

Ad hoc networks are an area of telecommunications that has grown in popularity due to its wide applicability. It also presents some interesting and difficult optimization problems. In this chapter we presented some of the optimization issues related to ad hoc networks, as well as techniques employed in their solution. This is an active area of research, and certainly will see many developments in the near future in terms of improved formulations and algorithms.

In this chapter, we introduced a collision model of a DS-CDMA network using random spreading sequences, where a collision is said to occur if there is no proper power control scheme for achieving a desired SINR at receivers. We derived and simulated the collision probabilities, assuming matched filter receivers.

A queueing analysis with the saturated slotted ALOHA model was conducted to study the MAC-layer throughput performance for systems equipped with enhanced packet reception capabilities, an example being the proposed collision model. Under a general physical reception model, the stability region for saturated slotted ALOHA for two transmitter—receiver pairs is explicitly characterized. Then we discussed throughput under a symmetric multipacket reception model, as a special case of the general reception model, and under the proposed collision model, as a special case of the symmetric multipacket reception model.

Multipath routing has been a promising technique in MANETs and WSNs. It has been shown through both theoretical analysis and simulation results that multipath routing provides many performance benefits, including improved fault tolerance, security, and reliability, improved routing efficiency and reduced routing overhead, more balanced traffic load and energy consumption, reduced end-to-end latency, and aggregated network bandwidth, etc. Significant research efforts have been made and are continuously being made in developing multipath routing protocols and multipath packet forwarding techniques in order to achieve the above-mentioned performance gains effectively and efficiently. Nevertheless, many issues that are directly related to the application of multipath routing remain untouched, such as the integration of the multipath routing into the current single-path routing paradigm, the synchronization of the packets among the multiple paths, and the interfaces of multipath routing protocols to other layers of protocol in the network protocol stack, etc.

Due to space limitations, we are only able to introduce the basic concept of multipath routing, highlight the fundamental techniques used to find the multiple paths, and outline the essential idea of what and why it can help in performance. For detailed algorithms/protocols as well as performance evaluations, interested readers are referred to respective publications.

In this chapter, the time-independent Green’s functions are defined, their main properties are presented, methods for their calculation are briefly discussed, and their use in problems of physical interest is summarized.

This chapter has addressed the challenges of large-scale on-demand data broadcasts introduced by broadcast media such as satellite networks, cable networks, wireless LANs, and cellular networks. In such environments, the scheduling problem is different from that in a point-to-point communication environment or a push-based broadcast environment. Moreover, when variable-sized heterogeneous requests are considered, most of the previous scheduling algorithms fail to perform well. As stretch is widely adopted as a performance metric for variable-size data requests, we proposed a broadcast scheduling algorithm to optimize the system performance in terms of stretch. One nice property of the proposed algorithm is that it is extremely simple and the computation overhead is very low. Analytical results described the intrinsic behavior of the algorithm. Simulation results demonstrated that our algorithm significantly outperforms existing scheduling algorithms under various scenarios.

This chapter has addressed the challenges of large-scale on-demand data broadcasts introduced by broadcast media such as satellite networks, cable networks, wireless LANs, and cellular networks. In such environments, the scheduling problem is different from that in a point-to-point communication environment or a push-based broadcast environment. Moreover, when variable-sized heterogeneous requests are considered, most of the previous scheduling algorithms fail to perform well. As stretch is widely adopted as a performance metric for variable-size data requests, we proposed a broadcast scheduling algorithm to optimize the system performance in terms of stretch. One nice property of the proposed algorithm is that it is extremely simple and the computation overhead is very low. Analytical results described the intrinsic behavior of the algorithm. Simulation results demonstrated that our algorithm significantly outperforms existing scheduling algorithms under various scenarios.