Position-Based Multicast Routing for Mobile Ad-Hoc Networks

In this paper we present Position-Based Multicast (PBM), a multicast routing algorithm for mobile ad-hoc networks which does neither require the maintenance of a distribution structure (e.g., a tree or a mesh) nor resorts to flooding of data packets. Instead a forwarding node uses information about the positions of the destinations and its own neighbors to determine the next hops that the packet should be forwarded to and is thus very well suited for highly dynamic networks. PBM is a generalization of existing position-based unicast routing protocols such as face-2 or GPSR. The key contributions of PBM are rules for the splitting of multicast packets and a repair strategy for situations where there exists no direct neighbor that makes progress toward one or more destinations. The characteristics of PBM are evaluated in detail by means of simulation

A Survey of Multicast Routing Protocols for Ad-Hoc Wireless Networks

Abstract Many network applications require transmitting the same single copy of data packets concurrently to many destinations, it is called multicasting. Wired and infrastructure-based wireless networks are supported by many multicast routing protocols. But, applying this concept in Mobile Ad hoc wireless NETworks (MANETs) is a big challenge. Ad hoc wireless networks composed of self-organized mobile nodes that can move arbitrarily without any preexisting communication infrastructure base stations. It causes producing dynamic and unpredictable network topology. Many proposals are introduced trying to solve multicast supporting problem in MANETs. In this paper, multicast routing protocols in MANETs that was proposed in recent years will be classified according to different view points such as multicast topology, topology initialization, topology maintenance, core or coreless approach, and dependency on unicast routing protocols

On the optimal operation of wireless networks

With the ever increasing mobile traffic in wireless networks, radio frequency spectrum is becoming limited and overcrowded. To address the radio frequency spectrum scarcity problem, researchers proposed advanced radio technology-Cognitive Radio to make use of the uncommonly used and under-utilized licensed bands to improve overall spectrum efficiency. Mobile service providers also deploy small base stations on the streets, into shopping center and users\u27 households in order to improve spectrum efficiency per area. In this thesis, we study cooperation schemes in cognitive radio networks as well as heterogeneous networks to reuse the existing radio frequency spectrum intelligently and improve network throughput and spectrum efficiency, reduce network power consumption and provide network failure protection capability. In the first work of the thesis, we study a multicast routing problem in Cognitive Ratio Networks (CRNs). In this work, all Secondary Users (SUs) are assumed not self interested and they are willing to provide relay service for source SUs. We propose a new network modeling method, where we model CRNs using a Multi-rate Multilayer Hyper-Graph (MMHG). Given a multicast session of the MMHG, our goal is to find the multicast routing trees that minimize the worst case end-to-end delay, maximize the multicast rate and minimize the number of transmission links used in the multicast tree. We apply two metaheuristic algorithms (Multi-Objective Ant Colony System optimization algorithm (MOACS) and Archived Multi-Objective Simulated Annealing Optimization Algorithm (AMOSA)) in solving the problem. We also study the scheduling problem of multicast routing trees obtained from the MMHG model. In the second work of the thesis, we study the cell outage compensation function of the self-healing mechanism using network cooperation scheme. In a heterogeneous network environment with densely deployed Femto Base Stations (FBSs), we propose a network cooperation scheme for FBSs using Coordinated Multi-Point (CoMP) transmission and reception with joint processing technique. Different clustering methods are studied to improve the performance of the network cooperation scheme. In the final work of the thesis, we study the user cooperative multi-path routing solution for wireless Users Equipment (UEs)\u27 streaming application using auction theory. We assume that UEs use multi-path transport layer service, and establish two paths for streaming events, one path goes through its cellular link, another path is established using a Wi-Fi connection with a neighbor UE. We study user coordinated multi-path routing solution with two different energy cost functions (LCF and EAC) and design user cooperative real-time optimization and failure protection operations for the streaming application. To stimulate UEs to participate into the user cooperation operation, we design a credit system enabled with auction mechanism. Simulation results in this thesis show that optimal cooperation operations among network devices to reuse the existing spectrum wisely are able to improve network performance considerably. Our proposed network modeling approach in CRN helps reduce the complicated multicast routing problem to a simple graph problem, and the proposed algorithms can find most of the optimal multicast routing trees in a short amount of time. In the second and third works, our proposed network cooperation and user cooperation approaches are shown to provide better UEs\u27 throughput compared to non-cooperation schemes. The network cooperation approach using CoMP provides failure compensation capability by preventing the system sum rate loss from having the same speed of radio resource loss, and this is done without using additional radio resources and will not have a significant adverse effect on the performance of other UEs. The user cooperation approach shows great advantage in improving service rate, improving streaming event success rate and reducing energy consumption compared to non-cooperation solution

Reliable Multicast in Mobile Ad Hoc Wireless Networks

A mobile wireless ad hoc network (MANET) consists of a group of mobile nodes communicating wirelessly with no fixed infrastructure. Each node acts as source or receiver, and all play a role in path discovery and packet routing. MANETs are growing in popularity due to multiple usage models, ease of deployment and recent advances in hardware with which to implement them. MANETs are a natural environment for multicasting, or group communication, where one source transmits data packets through the network to multiple receivers. Proposed applications for MANET group communication ranges from personal network apps, impromptu small scale business meetings and gatherings, to conference, academic or sports complex presentations for large crowds reflect the wide range of conditions such a protocol must handle. Other applications such as covert military operations, search and rescue, disaster recovery and emergency response operations reflect the mission critical nature of many ad hoc applications. Reliable data delivery is important for all categories, but vital for this last one. It is a feature that a MANET group communication protocol must provide. Routing protocols for MANETs are challenged with establishing and maintaining data routes through the network in the face of mobility, bandwidth constraints and power limitations. Multicast communication presents additional challenges to protocols. In this dissertation we study reliability in multicast MANET routing protocols. Several on-demand multicast protocols are discussed and their performance compared. Then a new reliability protocol, R-ODMRP is presented that runs on top of ODMRP, a well documented best effort protocol with high reliability. This protocol is evaluated against ODMRP in a standard network simulator, ns-2. Next, reliable multicast MANET protocols are discussed and compared. We then present a second new protocol, Reyes, also a reliable on-demand multicast communication protocol. Reyes is implemented in the ns-2 simulator and compared against the current standards for reliability, flooding and ODMRP. R-ODMRP is used as a comparison point as well. Performance results are comprehensively described for latency, bandwidth and reliable data delivery. The simulations show Reyes to greatly outperform the other protocols in terms of reliability, while also outperforming R-ODMRP in terms of latency and bandwidth overhead

Position-Based Multicast for Mobile Ad-hoc Networks

In general, routing protocols for mobile ad-hoc networks (MANETs) can be classified into topology-based protocols and position-based protocols. While for unicast routing many proposals for both classes exist, the existing approaches to multicast routing basically implement topology-based algorithms and only a few of them make use of the geographic positions of the network nodes. These have in common that the sending node has to precalculate the multicast tree over which the packets are distributed and store it in each packet header. This involves two main issues: (a) These approaches are not very flexible with regard to topological changes which abandons the advantages that position-based routing has against topology-based routing, and (b) they do not scale with the number of receivers, since every one of them has to be named in the packet header. This thesis solves these issues and further advances position-based multicast routing. Position-Based Multicast (PBM) enhances the flexibility of position-based multicast routing by following the forwarding principle of position-based unicast routing. It transfers the choice of the next hops in the tree from the sender to the forwarding nodes. Based on the positions of their neighboring nodes, these are able to determine the most suitable next hop(s) at the moment when the packet is being forwarded. The scalability with respect to the number of receiving nodes in a group is solved by Scalable Position-Based Multicast (SPBM). It includes a membership management fulfilling different tasks at once. First, it administers group memberships in order to provide multicast sources with information on whether nodes are subscribed to a specific group. Second, it implements a location service providing the multicast sources with the positions of the subscribed receiver nodes. And third, it geographically aggregates membership data in order to achieve the desired scalability. The group management features two modes of operation: The proactive variant produces a bounded overhead scaling well with the size of the network. The reactive alternative, in contrast, reaches low worst-case join delays but does not limit the overhead. Contention-Based Multicast Forwarding (CBMF) addresses the problems that appear in highly mobile networks induced by outdated position information. Instead of basing forwarding decisions on a perception that may no longer be up to date, the packets are addressed only to the final destination; no explicit next hops are specified. The receiving nodes, which are candidate next hops, then decide by means of contention which of them are the most suitable next hop(s) for a packet. Not only is the decision made based on the most currently available data, but this procedure also saves the regular sending of beacon messages, thus reducing the overhead. The lack of multicast congestion control is another unsolved problem obstructing high-bandwidth data transmission. Sending out more and more packets to a multicast group lets the performance decrease. Backpressure Multicast Congestion Control (BMCC) takes care that the network does not need to handle more packets than it is able to. It achieves this by limiting the packet queues on the intermediate hops. A forwarder may not forward the next packet of a stream before it has noticed---by overhearing the transmission of the next hop---that the previous packet has succeeded. If there is congestion in an area, backpressure is implicitly built up towards the source, which then stops sending out packets until the congestion is released. BMCC takes care that every receiving node will receive packets at the same rate. An alternative mode of operation, BMCC with Backpressure Pruning (BMCC-BP) allows the cutting of congested branches for single packets, permitting a higher rate for uncongested receivers. Besides presenting protocols for multicast communication in MANETs, this thesis also describes implementations of two of the above-mentioned protocols. The first one is an implementation of SPBM for the Linux kernel that allows IP applications to send data via UDP to a group of receivers in an ad-hoc network. The implementation resides between the MAC layer and the network/IP layer of the network stack. It is compatible with unmodified standard kernels of versions 2.4 and 2.6, and may be compiled for x86 or ARM processor architectures. The second implementation is an implementation of CBMF for the ScatterWeb MSB430 sensor nodes. Due to their low-level programmability they allow an integration of the routing protocol with the medium access control. The absence of periodic beacon messages makes the protocol especially suitable for energy-constrained sensor networks. Furthermore, other constraints like limited memory and computational power demand special consideration as well