The objective of this research is to investigate and develop an efficient and seamless data transport protocol for a heterogeneous wireless mobile network. In next-generation network, most of heterogeneous wireless mobile networks will be combined and complementarily constitute a hierarchical network. To integrate different networks, many challenging issues should be solved. In this thesis, an efficient and seamless data transport mechanisms are explored. We investigate the problems that the current transport control protocol (TCP) will experience within the heterogeneous mobile network. In a heterogeneous network, a mobile host experiences drastic changes in network condition during a session. Traditional TCP struggles with abrupt network changes by intersystem handoff and cannot work efficiently in this environment. We propose a TCP scheme to be tailored to the heterogeneous mobile network to support seamless data transport. In the proposed scheme, a TCP is informed the impending handoff events and works differently based on a handoff type. Simulation results present the proposed algorithm improves throughput, stabilizes data transmission rapidly, and provides a seamless data transfer. We also propose an adaptive resource management scheme within a 3G cellular network based on a users priority level to reduce the call dropping and blocking rates. In a heterogeneous network, a network that provides smaller bandwidth may struggle with handed-off calls being served with a higher bandwidth. Therefore, a resource management algorithm should be defined so that an ongoing call is not dropped by a handoff and provides seamless data transfer. We propose an adaptive resource management scheme based on downgrading the quality of some existing services in a 3G cellular network. We analyze the system capacity, call blocking rate and call dropping rate of the proposed algorithm, and simulate the performance variation of the downgraded traffic. The results show that the proposed scheme increases system capacity, and decreases the call dropping rate at the cost of small delay of the downgraded data traffic.

This work deals with multipath transmission in the data networks to speed up transmission over networks with limited transmission speed. Work compares the characteristics, efficiency and response to changes in individual transmission paths. Work is specifically dedicated to MPT and MPTCP mechanisms.

ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Incorporating network-based telemetry components into a flight test article creates new types of network-based data flows between a test article and a telemetry ground station. The emerging integrated Network Enhanced Telemetry (iNET) Standard defines new, network-based data delivery protocols which can produce various network data flows. Augmenting existing Serial Streaming Telemetry (SST) data flows with these network-based data flows is crucial to enhancing current flight test capabilities. This paper briefly introduces the network protocols referenced in the iNET Standard and then identifies the various data flows generated by network-based components which comply with the iNET Standard. Several combinations of SST and TmNS data flows are presented and the enhanced telemetry capabilities provided by each combination are identified. Identifying time intervals of unused telemetry network bandwidth explicitly for reallocation to other test articles is also addressed.

Providing efficient data transport is one of the uppermost objectives in the design of wireless sensor networks (WSNs) since the primary role for each sensor is to report the sensed data to the data sink(s). This thesis focuses on designing efficient data transport schemes for WSNs in the dimensions of energy consumption and time respectively. The developed schemes can be directly applied in a number of applications such as intrusion detection, target tracking, environment monitoring, etc., and can be further extended to underwater acoustic sensor networks and unmanned aerial vehicles (UAVs) networks. With the development of WSN technologies, new challenging research problems such as real-time streaming data gathering and intelligent data communication are emerging. This thesis provides useful foundation for designing next-generation data transport schemes for WSNs. Energy is the most important resource in WSNs because sensor nodes are commonly powered by small batteries, and energy is directly related to the lifetime of nodes and the network. In this thesis, energy-efficient data transport schemes are designed for two major types of WSNs: event-driven sensor networks and time-driven sensor networks. A novel on-line routing scheme called EBGR (Energy-efficient Beaconless Geographic Routing) is designed for event-driven sensor networks characterized by dynamic network topology. The main advantage of EBGR is that it can provide energy-efficient sensor-to-sink routing without any prior neighborhood knowledge. Moreover, the total energy consumption for sensor-to-sink data delivery under EBGR has an upper bound. Time-driven sensor networks, in which all sensors periodically report the sensed data to the sink(s), have been widely used for environment monitoring applications. Unbalanced energy consumption is an inherent problem in time-driven sensor networks. An efficient data gathering scheme, called EBDG (Energy-Balanced Data Gathering), is designed to balance energy consumption for the goal of maximizing network lifetime. Combing all advantages of corona-based network division,mixed-routing and data aggregation, EBDG can prolong network lifetime by an order of magnitude compared with conventional schemes. Time-efficient data transport is another critical issue in WSNs since the data generated by the sensor nodes may become outdated after a certain time interval. This thesis focuses on the problem of providing real-time data gathering in time-driven sensor networks. A novel data gathering scheme based on random access is proposed with the objective to minimize the average duration for completing one round of data gathering. Fully localized solutions have been designed for both linear networks and tree networks. A simple data gathering protocol called RADG (Random Access Data Gathering) is designed. Simulation results show that RADG outperforms CSMA based schemes when the size of the data packets is small. / Thesis (Ph.D.) -- University of Adelaide, School of Computer Science, 2009

This dissertation is a study on the design and analysis of novel, optimal routing and rate control algorithms in wireless, mobile communication networks. Congestion control and routing algorithms upto now have been designed and optimized for wired or wireless mesh networks. In those networks, optimal algorithms (optimal in the sense that either the throughput is maximized or delay is minimized, or the network operation cost is minimized) can be engineered based on the classic time scale decomposition assumption that the dynamics of the network are either fast enough so that these algorithms essentially see the average or slow enough that any changes can be tracked to allow the algorithms to adapt over time. However, as technological advancements enable integration of ever more mobile nodes into communication networks, any rate control or routing algorithms based, for example, on averaging out the capacity of the wireless mobile link or tracking the instantaneous capacity will perform poorly. The common element in our solution to engineering efficient routing and rate control algorithms for mobile wireless networks is to make the wireless mobile links seem as if they are wired or wireless links to all but few nodes that directly see the mobile links (either the mobiles or nodes that can transmit to or receive from the mobiles) through an appropriate use of queuing structures at these selected nodes. This approach allows us to design end-to-end rate control or routing algorithms for wireless mobile networks so that neither averaging nor instantaneous tracking is necessary, as we have done in the following three networks. A network where we can easily demonstrate the poor performance of a rate control algorithm based on either averaging or tracking is a simple wireless downlink network where a mobile node moves but stays within the coverage cell of a single base station. In such a scenario, the time scale of the variations of the quality of the wireless channel between the mobile user and the base station can be such that the TCP-like congestion control algorithm at the source can not track the variation and is therefore unable to adjust the instantaneous coding rate at which the data stream can be encoded, i.e., the channel variation time scale is matched to the TCP round trip time scale. On the other hand, setting the coding rate for the average case will still result in low throughput due to the high sensitivity of the TCP rate control algorithm to packet loss and the fact that below average channel conditions occur frequently. In this dissertation, we will propose modifications to the TCP congestion control algorithm for this simple wireless mobile downlink network that will improve the throughput without the need for any tracking of the wireless channel. Intermittently connected network (ICN) is another network where the classic assumption of time scale decomposition is no longer relevant. An intermittently connected network is composed of multiple clusters of nodes that are geographically separated. Each cluster is connected wirelessly internally, but inter-cluster communication between two nodes in different clusters must rely on mobile carrier nodes to transport data between clusters. For instance, a mobile would make contact with a cluster and pick up data from that cluster, then move to a different cluster and drop off data into the second cluster. On contact, a large amount of data can be transferred between a cluster and a mobile, but the time duration between successive mobile-cluster contacts can be relatively long. In this network, an inter-cluster rate controller based on instantaneously tracking the mobile-cluster contacts can lead to under utilization of the network resources; if it is based on using long term average achievable rate of the mobile-cluster contacts, this can lead to large buffer requirements within the clusters. We will design and analyze throughput optimal routing and rate control algorithm for ICNs with minimum delay based on a back-pressure algorithm that is neither based on averaging out or tracking the contacts. The last type of network we study is networks with stationary nodes that are far apart from each other that rely on mobile nodes to communicate with each other. Each mobile transport node can be on one of several fixed routes, and these mobiles drop off or pick up data to and from the stationaries that are on that route. Each route has an associated cost that much be paid by the mobiles to be on (a longer route would have larger cost since it would require the mobile to expend more fuel) and stationaries pay different costs to have a packet picked up by the mobiles on different routes. The challenge in this type of network is to design a distributed route selection algorithm for the mobiles and for the stationaries to stabilize the network and minimize the total network operation cost. The sum cost minimization algorithm based on average source rates and mobility movement pattern would require global knowledge of the rates and movement pattern available at all stationaries and mobiles, rendering such algorithm centralized and weak in the presence of network disruptions. Algorithms based on instantaneous contact, on the contrary, would make them impractical as the mobile-stationary contacts are extremely short and infrequent. / text

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