Yangcheng Huang | Ericsson - Academia.edu (original) (raw)

Papers by Yangcheng Huang

Building and maintaining a reliable, high performance network infrastructure requires the ability... more Building and maintaining a reliable, high performance network infrastructure requires the ability of accurately visualizing, rapidly navigating and effectively resolving performance impacting issues. With the growing number of network entities and services, exploratory monitoring of a large-scale telecommunication network is becoming increasingly difficult. This paper presents a density hierarchy clustering algorithm, designed for real-time visualization of large telecommunications networks. The

Recently, Grid and peer-to-peer overlays have attracted attention from research communities as we... more Recently, Grid and peer-to-peer overlays have attracted attention from research communities as well as industry. However, the overwhelming majority of industrial, commercial and academic activities are geared around applications, servers, and middleware. There have been some efforts in the management of the underlying networks (the connectivity for the overlays), but far from enough. This paper proposes a resilient, fault-adaptive, overlay resource management framework, with lightweight state management infrastructure, taken from some ongoing work by the authors in this area. This research aims to solve the problems of: (a) managing distributed network resources in a decentralized way; (b) providing resilient QoS for highly dynamic networks. NRA_Unregister: Unregister a Grid service handle;

The concept of soft state was introduced in the late 1980s and has been widely used in various In... more The concept of soft state was introduced in the late 1980s and has been widely used in various Internet protocols. However, there is still no comprehensive understanding or well-accepted models on performance (resilience, robustness etc.) of soft state protocols. This paper presents a model based analysis on resilience of soft state signalling protocols based on probability theory. The model could be used to evaluate failure recovery time in the presence of state inconsistency for protocols such as RSVP. This work in progress aims towards an accurate and comprehensive model for signalling protocols.

This paper presents the design of a scalable decentralized signaling underlay infrastructure, whi... more This paper presents the design of a scalable decentralized signaling underlay infrastructure, which features a DHT based management information storage and query-based state lookup mechanism. The signaling underlay is aimed to apply a decentralized "peer-to-peer" style searching and discovering engine into the management and control plane of the overlay network, including grid networks and p2p applications, to facilitate deployment of QoS service.

Wireless Personal Communications, 2009

We propose a cross-layer routing protocol for a Code Division Multiple Access (CDMA) Multihop Cel... more We propose a cross-layer routing protocol for a Code Division Multiple Access (CDMA) Multihop Cellular Network (MCN). In designing the routing protocol for MCN, multiple constraints are imposed on intermediate relay node selection and end-to-end path selection. The constraints on relay nodes include willingness for cooperation, sufficient neighbourhood connectivity and the level of interference offered on the path. Path constraints include end-to-end throughput and end-to-end delay. A facile incentive mechanism is presented to motivate the cooperation between nodes in call forwarding. In addition, we present a route resilience scheme in the event of dynamic call dropping. In particular, a fast neighbour detection scheme for route resilience is proposed. Instead of using periodic HELLO messages as in traditional ad-hoc routing, the proposed neighbour detection scheme adopts an explicit handshake mechanism to reduce neighbour detection latency. We conclude the paper by demonstrating the superior performance of the proposed routing protocol compared with the other well known routing algorithms.

International Journal of Parallel, Emergent and Distributed Systems, 2008

Although there have been a number of performance studies of proactive mobile ad hoc network (MANE... more Although there have been a number of performance studies of proactive mobile ad hoc network (MANET) routing protocols, little attention has been paid to the impacts of topology update strategies on routing performance. This paper presents an analysis of several topology update strategies for a proactive MANET routing protocol. The goal of this paper is to better understand how topology update strategies can contribute to topology maintenance in proactive MANETs and thus impact the overall performance, based on simulations involving optimised link state routing (OLSR), a popular MANET protocol. Our contribution includes (1) a quantitative analysis of the impacts of proactive update intervals on the routing performance of OLSR; (2) evaluating the performance of reactive topology updates and proactive updates for OLSR.

In wireless mission-critical systems, systems may be resource-constrained including limited bandw... more In wireless mission-critical systems, systems may be resource-constrained including limited bandwidth, so minimising protocol overhead, whilst maintaining performance, is important. Proactive MANET routing protocols tend to provide smaller route discovery latency than on-demand protocols because they maintain route information to all the nodes in the network at all time. However, such protocols may impose excessive soft-state routing control overhead which is generated by disseminating periodic update messages. In order to mitigate the side effects of the soft-state control overheads, we propose two adaptive proactive routing algorithms, namely DT MIAD and DT ODPU. By tuning the value of refresh intervals dynamically and automatically, refresh updates are triggered based on traffic conditions and node mobility. We show through simulations that the proposed adaptive routing algorithms can outperform a traditional proactive routing protocol (OLSR).

A major concern about distance-vector routing protocols for wireless mesh networks is its slow co... more A major concern about distance-vector routing protocols for wireless mesh networks is its slow convergence in the presence of link changes, which can potentially degrade network stability. This paper studies the impact of update intervals on network convergence and proposes a fast-converging distance-vector routing algorithm. Our simulation results have shown that the proposed algorithm could effectively reduce convergence latency and improve throughput without leading to a significant increase in control overhead.

This paper presents an analysis of several topology update strategies for proactive MANET routing... more This paper presents an analysis of several topology update strategies for proactive MANET routing protocols. Although there have been a number of performance studies of proactive MANET routing protocols, little attention has been paid to the impacts of topology update strategies on routing performance. The goal of this paper is to better understand how topology update strategies can contribute to topology maintenance in proactive mobile ad hoc networks and thus impact the overall performance. Our contribution includes (1) a quantitative analysis on the impacts of proactive update intervals on the routing performance; (2) evaluating the performance of reactive topology updates and proactive updates for proactive routing protocols.

Rapid and unpredictable topology changes and resource constraints make delivering packets in a MA... more Rapid and unpredictable topology changes and resource constraints make delivering packets in a MANET (Mobile Ad hoc Network) a challenging task. Routing information has to be updated to reflect the topology changes and maintain the correctness of route selection. On the other hand, the dissemination of control messages has to be optimised for efficient resource usage and to alleviate channel contention problems. To solve this problem, this dissertation focuses on how to automatically tune routing performance for MANETs in terms of packet delivery ratio and control overhead. The impacts of soft state signalling, especially the refresh intervals, are studied under various scenarios. A variety of topology advertisement strategies are presented. Two self-tuning neighbour detection schemes are proposed, the Dynamic Timer algorithm and the Fast Neighbour Handshake algorithm, in order to enhance routing performance.

Proactive MANET routing protocols tend to provide smaller route discovery latency than ondemand p... more Proactive MANET routing protocols tend to provide smaller route discovery latency than ondemand protocols because they maintain route information to all the nodes in the network at all time. However, the downside for such protocols is the excessive routing control overhead that is generated by disseminating periodic HELLO messages and topology control messages. Due to the resource-constrained nature of wireless networks, the routing overhead increases channel contention, leads to network congestions and lowers significantly network performance. In order to mitigate the side effects of the soft update control overheads, we propose two adaptive proactive routing algorithms, namely DT MIAD and DT ODPU. By tuning the value of refresh intervals dynamically and automatically, refresh updates are triggered based on traffic conditions and node mobility. We have shown through simulations that, the proposed adaptive routing algorithm outperforms traditional proactive routing protocols like OLSR.

This paper presents a fast neighbour detection scheme for proactive a MANET routing protocol. Ins... more This paper presents a fast neighbour detection scheme for proactive a MANET routing protocol. Instead of using periodic HELLO messages, the proposed scheme adopts explicit handshake mechanism to reduce the latency in neighbour detection. In particular, two route handshake options are presented, namely the Broadcast based handshake (BHS) algorithm and Unicast based handshake (UHS) algorithm. Our simulation results show that the proposed scheme improves routing performance, especially in networks with moderate or high mobility. In low-density networks, the unicast option improves the routing throughput significantly without introducing extra control overhead.

... The proposed signalling solutions aim at reducing data packet losses by reducing failure dete... more ... The proposed signalling solutions aim at reducing data packet losses by reducing failure detection latency ... state information in each topology control message). ... node movement could help balance routing performance and control overhead. However, the per-...

One critical issue of MANET is to improve packet delivery in presence of network dynamics. Proact... more One critical issue of MANET is to improve packet delivery in presence of network dynamics. Proactive MANET routing protocols tend to provide smaller route discovery latency than ondemand protocols because they maintain route information to all the nodes in the network at all time. However, the downside for such protocols is the excessive routing control overhead generated by disseminating periodic HELLO messages and topology control messages. Due to the resource-constrained nature of wireless networks, the routing overhead increases channel contention, leads to network congestions and lowers significantly network performance. In order to mitigate the side effects of the soft update control overheads, we propose an adaptive neighbor detection algorithm for MANET routing protocols, namely DT MIAD. By tuning the value of refresh intervals dynamically and automatically, refresh updates are triggered based on traffic conditions and node mobility. We have shown through simulations that, the proposed adaptive routing algorithm outperforms traditional proactive routing protocols like OLSR.

This paper describes, briefly, ongoing research on resource reservation state management, includi... more This paper describes, briefly, ongoing research on resource reservation state management, including research motivations and initial design.

Optimised Link State Routing (OLSR) is a popular protocol for use in MANET networks. In this pape... more Optimised Link State Routing (OLSR) is a popular protocol for use in MANET networks. In this paper, we investigate the different impacts of tuning refresh interval timers on OLSR performance under various scenarios (varying node density and node speed). Based on the simulation results with NS2, we find that although reducing refresh intervals could improve OLSR's performance, the intervals for some message types (HELLO messages) have a bigger impact on OLSR performance than for other message types. We find that the impact of the interval timer grows with increased network mobility and node density.

Journal of Networks, 2009

In Mobile Ad hoc Networks (MANETs), timers have been used widely to maintain routing (state) info... more In Mobile Ad hoc Networks (MANETs), timers have been used widely to maintain routing (state) information. The use of fixed-interval timers is simple to implement but, in practise, may be difficult to configure in dynamic operational environments, and so may give reduced performance in the presence of frequent topology changes. This paper proposes a self-tuning timer approach within a simple control system for MANET routing protocols with the aim of allowing dynamic, autonomic, re-calibration of routing update frequencies. A novel dynamic timer algorithm is presented to automatically tune routing performance by adapting timer intervals to network conditions. Our simulation results have shown that, compared to the default fixed timer approach, the proposed algorithm could effectively improve routing throughput without manual configuration.

In Mobile Ad hoc Networks (MANETs), timers have been widely used to maintain routing (state) info... more In Mobile Ad hoc Networks (MANETs), timers have been widely used to maintain routing (state) information. The use of fixed-interval timers is simple to implement but, in practise, may be difficult to configure in dynamic operational environments, and so may give reduced performance in the presence of frequent topology changes. This paper proposes a self-tuning timer approach within a simple control system for MANET routing protocols with the aim of allowing dynamic, autonomic, re-calibration of routing update frequencies. A novel dynamic timer algorithm is presented to automatically tune routing performance by adapting timer intervals to network conditions. Our simulation results have shown that, compared to the default fixed timer approach, the proposed algorithm could effectively improve routing throughput without manual configuration.

This paper investigates the route dynamics of Shortest-Path First (SPF) routing in mobile ad hoc ... more This paper investigates the route dynamics of Shortest-Path First (SPF) routing in mobile ad hoc networks (MANETs). In particular, we find, from a statistical analysis of route duration and route change interval, that route dynamics may require complex modelling. Our analysis considers various mobility models, node velocities and node densities of the MANET network. Our findings show that, in a MANET with moderate or high rate of mobility, the route duration could be approximated by an exponential distribution with approximate parameters, while the route duration of specific lengths could not. Our findings suggest that minimum hop-count routing in MANETs may be inappropriate and that further investigation is required in order to develop models that let us understand MANET route dynamics.

Wireless Personal Communications, 2009

International Journal of Parallel, Emergent and Distributed Systems, 2008

Journal of Networks, 2009