Wanrong Yu

A High-Throughput MAC Protocol for Wireless Ad Hoc Networks

One way to improve the throughput of a wireless ad hoc network at the media access (MAC) layer is to allow as much as possible concurrent transmissions among neighboring nodes. In this paper, we present a novel high-throughput MAC protocol, called Concurrent Transmission MAC(CTMAC), which supports concurrent transmission while allowing the network to have a simple design with a single channel, single transceiver, and single transmission power architecture. CTMAC inserts additional control gap between the transmission of control packets (RTS/CTS) and data packets (DATA/ACK), which allows a series of RTS/CTS exchanges to take place between the nodes in the vicinity of the transmitting or receiving node to schedule possible multiple, concurrent data transmissions. To safeguard the concurrent data transmission, collision avoidance information is included in the control packets and used by the neighboring nodes to determine whether they should begin their transmissions. Also, to isolate the possible interference between DATA packets and ACK packets, a new ACK sequence mechanism is proposed. Simulation results show that a significant gain in throughput can be obtained by the CTMAC protocol compared with the existing work including the IEEE 802.11 MAC protocol.

OpenSAN: a software-defined satellite network architecture

In recent years, with the rapid development of satellite technology including On Board Processing (OBP) and Inter Satellite Link (ISL), satellite network devices such as space IP routers have been experimentally carried in space. However, there are many difficulties to build a future satellite network with current terrestrial Internet technologies due to the distinguished space features, such as the severely limited resources, remote hardware/software upgrade in space. In this paper, we propose OpenSAN, a novel architecture of software-defined satellite network. By decoupling the data plane and control plane, OpenSAN provides satellite network with high efficiency, fine-grained control, as well as flexibility to support future advanced network technology. Moreover, we also discuss some practical challenges in the deployment of OpenSAN.

A high-throughput MAC protocol for wireless ad hoc networks

One way to improve the throughput of a wireless ad hoc network at the media access (MAC) layer is to allow as much as possible concurrent transmissions among neighboring nodes. In this paper, we present a novel high-throughput MAC protocol, called Concurrent Transmission MAC(CTMAC), which supports concurrent transmission while allowing the network to have a simple design with a single channel, single transceiver, and single transmission power architecture. CTMAC inserts additional control gap between the transmission of control packets (RTS/CTS) and data packets (DATA/ACK), which allows a series of RTS/CTS exchanges to take place between the nodes in the vicinity of the transmitting or receiving node to schedule possible multiple, concurrent data transmissions. To safeguard the concurrent data transmission, collision avoidance information is included in the control packets and used by the neighboring nodes to determine whether they should begin their transmissions. Also, to isolate the possible interference between DATA packets and ACK packets, a new ACK sequence mechanism is proposed. Simulation results show that a significant gain in throughput can be obtained by the CTMAC protocol compared with the existing work including the IEEE 802.11 MAC protocol.

Ferry Route Design with Delay Bounds in Delay-Tolerant Networks

Delay-Tolerant/Disruption-Tolerant Networks (DTNs) have been proposed to cope with the challenges of communication in some extreme or special environments. Due to the uncertainty of node mobility, application traffic demand and other factors, it is difficult to provide performance guarantee for a DTN where all nodes may move arbitrarily. With controlled mobility, message ferries can be utilized to guarantee the network performance. Central to the problem is the design of ferry routes under some constraints. In this paper, we consider the delay requirements in DTNs and study the multiple ferry route design problem with delay constraints. We formulate the problem as a global optimization problem and give the conditions when a solution is valid and when there is no valid solution to the problem. Then a heuristic algorithm is proposed to find the minimal number of ferries and the ferry routes subject to the delay bounds. The algorithm performance is evaluated and compared to the SIRA algorithm. The experiment results have shown that the performance of a DTN can be guaranteed using a reasonable number of message ferries moving along the ferry routes found by the proposed algorithm.

Software defined satellite networks: Benefits and challenges

To date, traditional satellite systems are contained-designed and inflexible for configuration update, space systems interconnections and providing fine-grained services. In this paper, we propose a novel satellite network architecture: software defined satellite networks (SDSN) to solve these problems. The new architecture is based on the central control patten of software defined networks (SDN), and takes full use of the inter-satellite links (ISLs) forwarding and GEO broadcasting for rapid network deployment. With global network view and central control ability, SDSN can (1) balance the flexibility and controllability of space dynamic routing algorithms, (2) rapidly deploy flexible and fine-grained network management strategies, (3) reduce the system cost, and (4) improve the collaboration between satellites and the compatibility of heterogeneous space systems. Meanwhile, the challenges are also introduced in designing and deploying the new architecture. Finally, the performance of the new SDSN architecture is validated in this paper.

Qphone: a quantum security VoIP phone

This work presents a novel quantum security VoIP phone, called Qphone. Qphone integrates quantum key distribution (QKD) and VoIP steganography, and achieves peer-to-peer communication with information-theoretical security (ITS) guaranteeing. Qphone consists of three parts, a real-time QKD system, RT-QKD, a steganography software, VS-Phone, and an audio encryption and authentication hardware, AE-KEY. RT-QKD explores QKD technologies, and is able establish a shared key between two peers ensuring ITS. VS-Phone utilizes VoIP steganography to protect transmission channels of sensitive information. Qphone can provide efficient and real-time security protections to meet different security demands.

A real-time privacy amplification scheme in quantum key distribution

QKD (Quantum Key Distribution) technology, based on the laws of physics, can create an unconditionally secure key between communication parties. In recent years, researchers draw more and more attention to the QKD technology. Privac amplification is a very significant procedure in QKD system. In this paper, we propose the real-time privacy amplification (RTPA) scheme which converts the weak secret string W to a uniform key that is fully secret from Eve. We implement RTPA scheme based on CLIP (Cvqkd Ldpc experImental Platform) which is connected to the real quantum communication systems. Experimental results show that, our proposed RTPA scheme is very efficient when the bit error rate of quantum channel is lower than 0.06.

CLIP: A Distributed Emulation Platform for Research on Information Reconciliation

In the quantum key distribution (QKD) system, information reconciliation is an essential component within the QKD post processing. Emulation techniques play an important role in information reconciliation since it enables the research of information processing to be independent with expensive and time-consuming physical systems. In this paper, we design CLIP, a novel Cross-pLatform quantum Information reconciliation experimental tool. CLIP is written in the C++ language to run at various platforms(including Linux and Windows, etc.), and it works in a distributed paradigm to enhance the experimental performance. We conducted numerous experiments on Quantum LDPC codes and evaluate the performance using our CLIP tool. Experimental results show that our LDPC platform is very powerful on the research of Information reconciliation.

SARM: A Congestion Control Algorithm for DTN

When congestion happens at the node of DTN, the regular approach is to delete the old message of these nodes in order to make memory space for the new arrival message to remove congestion. A new method for the selection of message to delete, congestion control routing algorithm based on Simulated Annealing and regional movement (SARM) are proposed in this paper. This mechanism is under the premise that node movement has the regional characteristic. The probability of node collision and transferring nodes in the message delivery are taken into account comprehensively. We quantitatively evaluate the successful probability of different messages delivered by different nodes. When node congestion happens, we choose the message with lower probability of successful delivered by two encounter nodes to delete using SARM. The experiment shows that the parameters of network are significantly improved under this congestion control routing algorithm.

MSN: a mobility-enhanced satellite network architecture: poster

The proposed MSN architecture is intended to directly address the challenge of mobility, which refers to the motion of users as well as the dynamics of the satellite constellation. A virtual access point layer consisting of fixed virtual satellite network attachment points is superimposed over the physical topology in order to hide the mobility of satellites from the mobile endpoints. Then the MSN enhances endpoint mobility by a clean separation of identity and logical network location through an identity-to-location resolution service, and taking full advantage of the users geographical location information. Moreover, a SDN based implementation is presented to further illustrate the proposal.