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In mobile networks, handover mechanisms provide fast and smooth access service for mobile users. However, one of the main challenges in mobile networks is the handover management with increased mobility and bandwidth demand of the required network services. Therefore, in this paper, we propose a MOS-aware (mean opinion score-aware) mobile network handover mechanism based on deep learning to determine the appropriate handover time for real-time video conference services in mobile networks. We construct a wireless network topology with LTE characteristics in a Mininet-WiFi simulation. User equipment (UE) can determine the service-required MOS (Mean Opinion Score) from the proposed deep-learning-based handover mechanism with appropriate handover time. Simulation results show that the proposed scheme provides higher performance than the original A3 handover mechanism. The contribution of this paper is to combine the real-time video conferencing services with a deep-learning-based handover mechanism by predicting MOS values to improve the quality of service for users in mobile networks.

The Software Defined Network (SDN) provides higher programmable functionality for network configuration and management dynamically. Moreover, SDN introduces a centralized management approach by dividing the network into control and data planes. In this paper, we introduce a deep learning enabled intrusion detection and prevention system (DL-IDPS) to prevent secure shell (SSH) brute-force attacks and distributed denial-of-service (DDoS) attacks in SDN. The packet length in SDN switch has been collected as a sequence for deep learning models to identify anomalous and malicious packets. Four deep learning models, including Multilayer Perceptron (MLP), Convolutional Neural Network (CNN), Long Short-Term Memory (LSTM) and Stacked Auto-encoder (SAE), are implemented and compared for the proposed DL-IDPS. The experimental results show that the proposed MLP based DL-IDPS has the highest accuracy which can achieve nearly 99% and 100% accuracy to prevent SSH Brute-force and DDoS attacks, respectively.

Many industrial wireless sensor networks deploy the IEEE 802.15.4-2015 standard with low power consumption and the Internet networking capabilities. The time-slotted channel hopping (TSCH) is an amendment to the medium access control protocol defined by the IEEE 802.15.4 standard. Furthermore, the Internet engineering task force (IETF) defines an architecture for IPv6 over the TSCH mode of IEEE 802.15.4 (6TiSCH) to provide deterministic properties on wireless sensor networks. The TSCH leverages the scheduled time slot to achieve low power operation and frequency hopping to combat external interference and multi-path fading. Although TSCH provides the channel hopping mechanism to increase transmission reliability, it is still susceptible to periodic interference for the specific frequency. In this research, we focus on the issue of random channel hopping in the error-prone wireless channel condition and the scheduling for different service requirements. We propose a priority-based scheduling using best channel (P-SBC) mechanism for periodic sensing data and emergency packets transmission in 6TiSCH networks. The simulation results show that the proposed P-SBC achieves higher reliability with significantly lower end-to-end latency for emergency packets transmission as compared to TSCH standard.

The routing protocol for low power and lossy network (RPL), constructed according to the objective function (OF), is the standard for routing selection in low power and lossy networks (LLNs). Most schemes utilise the expected transmission count (ETX) as the routing metric for the next hop. Designing effective and efficient routing protocols in LLNs require the mechanism to meet the criteria of different applications or services. In this paper, we propose a service-aware OF with quality of service (SOF-QoS) mechanism which integrates received signal strength indicator (RSSI), energy consumption, and hop count metrics into RPL OF for path selection according to different services, such as normal data, video packets and emergency messages transmission in LLNs. The proposed SOF-QoS mechanism defines various weights with fuzzy logic for the next routing selection in response to each service. We conduct the simulation under different network topologies with static and mobile scenarios to analyse the performance of the proposed SOF-QoS mechanism and compare them with the traditional RPL schemes. The simulation result shows that our proposed SOF-QoS mechanism provides relatively better or superior performance with reliability than traditional ones for different services.

In recent years, software defined networking (SDN) has become a novel network architecture and design by employing manageable software between the control and data planes. Many SDN-based intrusion detection systems (IDS) have been proposed in recent researches. On the other hand, deep learning has emerged as an explosive growth in research and industry. The application of deep learning on IDS has been studied in many security-critical scenarios. However, some reports has indicated the vulnerability of adversarial attacks on deep learning IDS system with intentional perturbation injection or manipulation. It is important for the empowered IDS system employing deep learning to be responsible for not leading misclassification. Therefore, exploring the impact on the adversarial attacks over SDN networks or security-critical scenarios applying deep learning is an important step to confront such urgent issues. In this paper, we will conduct the SDN-based experiments on adversarial attacks for deep learning detecting system. We propose a novel class of adversarial attacks that exploits the vulnerability of the deep learning classifiers in SDN environment. Three typical deep learning models combining with four different adversarial testing will be conducted in the simulation for complete analysis.

The technology of Internet of Things is gradually maturing. IoT has applied in many fields and extended to industrial networks. Thus, the IETF has proposed 6TiSCH (IPv6 over the TSCH mode of IEEE 802.15.4e) to establish the link between Internet and IWSNs (Industrial Wireless Sensor Networks). The main purpose of this research is to enhance the performance of Multi-hop 6TiSCH network by using the proposed Priority-based Fast Forward Scheduling Function (PFFSF). According to the simulation results, the proposed PFFSF has lower end-to-end transmission delay and higher throughput then the original 6TiSCH SF0 mechanism.

The recent IEEE 802.15.4-2015 standard proposes a number of Medium Access Control (MAC) layer protocols for low-power and lossy networks. The Timeslotted Channel Hopping (TSCH) is one of the proposed MAC operation modes, which take the advantage of channel hopping to make the transmissions more reliable and deterministic. In TSCH, slotframe is sliced into a timeslots and random channel hopping is used to mitigate the effects of co-channel interference and multipath fading. In this paper, we focus on the issue of random channel hopping in the error-prone wireless channel condition. In this research, a QoS Channel Allocation Scheme (QCAS) is proposed to enhance the reliability of emergency packet transmission in 6TiSCH networks. Based on our simulation results, we have observed that the proposed QCAS can achieve higher reliability of transmission over selected channel to provide higher throughput and higher delivery ratio than the original TSCH.

Wireless multimedia sensing network, used to transmit multimedia files over zigbee wireless communication, faces a big challenge in terms of transmission bandwidth and node lifetime. In this paper, we will implement the testbed of 6LoWPAN transmission for video service. We used Contiki OS to implement the wireless zigbee Zigduino nodes. We first simulated the packet loss of video transmission to optimize the packet loss recovery mechanism. Then we conducted the testbed to analyze the performance and feasibility of the wireless zigbee communication for video transmission.

In recent years, within large cities with a high population density, traffic congestion has become more and more serious, resulting in increased emissions of vehicles and reducing the efficiency of urban operations. Many factors have caused traffic congestion, such as insufficient road capacity, high vehicle density, poor urban traffic planning and inconsistent traffic light cycle configuration. Among these factors, the problems of traffic light cycle configuration are the focal points of this paper. If traffic lights can adjust the cycle dynamically with traffic data, it will reduce degrees of traffic congestion significantly. Therefore, a modified mechanism based on Q-Learning to optimize traffic light cycle configuration is proposed to obtain lower average vehicle delay time, while keeping significantly fewer processing steps. The experimental results will show that the number of processing steps of this proposed mechanism is 11.76 times fewer than that of the exhaustive search scheme, and also that the average vehicle delay is only slightly lower than that of the exhaustive search scheme by 5.4%. Therefore the proposed modified Q-learning mechanism will be capable of reducing the degrees of traffic congestions effectively by minimizing processing steps.

6LoWPAN technology has attracted extensive attention recently. It is because 6LoWPAN is one of Internet of Things standard and it adapts to IPv6 protocol stack over low-rate wireless personal area network, such as IEEE 802.15.4. One view is that IP architecture is not suitable for low-rate wireless personal area network. It is a challenge to implement the IPv6 protocol stack into IEEE 802.15.4 devices due to that the size of IPv6 packet is much larger than the maximum packet size of IEEE 802.15.4 in data link layer. In order to solve this problem, 6LoWPAN provides header compression to reduce the transmission overhead for IP packets. In addition, two selected routing schemes, mesh-under and route-over routing schemes, are also proposed in 6LoWPAN to forward IP fragmentations under IEEE 802.15.4 radio link. The distinction is based on which layer of the 6LoWPAN protocol stack is in charge of routing decisions. In route-over routing scheme, the routing distinction is taken at the network layer and, in mesh-under, is taken by the adaptation layer. Thus, the goal of this research is to understand the performance of two routing schemes in 6LoWPAN under error-prone channel condition.

Voice over Internet protocol (VoIP) has been a prevalent multimedia service nowadays. It allows us to transmit voice data over IP networks. However, quality of service (QoS) is a major challenge to VoIP services. It must provide similar quality to traditional public switched telephone network or cellular phone services. Therefore, QoS related protocols have become important for real-time applications. Multi-protocol label switch (MPLS) is one of the important techniques to improve the network performance from QoS point of view. It employs label swapping to speed up packet forwarding. However, when a large number of users utilize VoIP services, the network congestion issue still exists. It causes delay, jitter and packet loss that affect VoIP QoS. In this paper, we propose a QoS-aware path switching strategy by using stream control transmission protocol (SCTP) in MPLS network to improve the VoIP traffic. This was done by employing SCTP selective acknowledgment mechanism to report the transmission parameters of primary path and to determine the criteria to switch to backup path. Simulation results show significant improvement in VoIP QoS.

Advances of the identifying, sensing, and communicating technologies make the applications of Internet of Things (IoT) possible. Among others, the ubiquitous deployment of wireless sensor networks (WSNs) is regarded as one of the most significant forces in the IoT. Great progress in micro-electro-mechanical systems and wireless communications make the applications of WSNs more and more accessible. The limited battery power of the sensor node is vitally precious. Therefore, it is important to promote the energy efficiency to stretch the lifetime of the WSNs. In this paper, a low-power data transmission protocol, which includes a dual-frequency model, local synchronization, and channel reservation, is proposed. The results of numerical analyses and simulations show that the proposed protocol presents better energy efficiency without sacrificing end-to-end latency of data transmission in WSNs.

In this paper we design and implement the pseudo session initiation protocol (p-SIP) server embedded in each mobile node to provide the ad-hoc voice over Internet protocol (VoIP) services. The implemented p-SIP server, being compatible with common VoIP user agents, integrates the standard SIP protocol with SIP presence to handle SIP signaling and discovery mechanism in the ad-hoc VoIP networks. The ad-hoc VoIP signaling and voice traffic performances are analyzed using E-model R rating value for up to six hops in the implemented test-bed. We also conduct the interference experiments to imitate the practical ad-hoc VoIP environment. The analyzed results demonstrate the realization of ad-hoc VoIP services by using p-SIP server.

It is an important issue to provide the reliability as well as to balance the traffic load for the multihomed networks. In this paper, we deal with two most important factors, traffic load balancing and redundancy. The assigned weight for each link is dynamically computed according to the arrival and service rates via arrival rate dependent (ARD). By employing the adaptive-ARD (A-ARD) mechanism, the network performance in terms of average waiting time was further improved. The simulation result showed that more than 20% performance improvement was achieved by comparing A-ARD to RR, WRR and ARD with arrival rate 80 packets per second. Through the proposed redundancy scheme of A-ARD, the reliability of the packet transmission was fulfilled.

Mobile Stream Control Transmission Protocol (mSCTP) has been proposed to support transport layer mobility management mostly based on the radio signal strength. It could result in aggregation of mobile stations accessed via a base station with the strongest signal in the same signal overlapped area and consequently decrease the transmission probability in wireless networks. In this paper, we propose a cross layer handoff mechanism based on mSCTP, named CL-mSCTP, which combines the layer 4 heartbeat successful contention probability with the link signal strength detection to accomplish the dynamic handoff management. The simulation results show that the CL-mSCTP achieves much better performance in terms of throughput and the balancing of traffic loading than mSCTP does.

Thin films of BaTiO3 were deposited on single-crystal Si using rf magentron sputtering. Different microstructures resulted from varying the substrate temperature during sputtering or from post-annealing after film deposition. High trap and surface state densities at the interface between BaTiO3 and were found for the films deposited at room temperature even though such showed a relatively low leakage current and a high breakdown voltage. These surface states or traps, nevertheless, could be partially annealed out of the film a temperature around 450°C. High deposition temperatures above 600°C introduced unrecoverable surface states at the interface. BaTiO3 thin films were deposited at a substrate temperature in the range 450-500°C gave the performance in terms of their electrical and interface properties. BaTiO3 thin-film capacitors with a configuration of Au/BaTiO3/p-Si/Al, fabricated with optimized BaTiO3 thin-film deposition conditions, showed a value of the dielectric constant near 30, a leak...

Ferroelectric PbZr x Ti 1− x O 3 (PZT) thin films have been deposited on Pt-coated Si substrates by using r.f. magnetron sputtering. The optimized processing condition to obtain proper stoichiometric PZT, the desired ferroelectric perovskite phase, and better dielectric properties was demonstrated using a PZT target with Pb/(Zr + Ti) ratio of 1.2 and depositing at 350 °C, followed by thermal treatment at 620 °C for 30 min. The structural and electrical properties of the PZT layer were further improved by fabricating a novel multilayer structure which combined the PZT with the nanolayer BaTiO 3 . The leakage current density was reduced from 2 × 10 −7 A cm −2 for the single layer structure to 2 × 10 −9 A cm −2 for the multilayer structure at a field of 4 × 10 5 V cm −1 , while maintaining the high relative effective dielectric constant of 442. The relative dielectric constant of the PZT film in the multilayer structure was calculated to be about 880.

6LoWPAN is one of Internet of Things standard, which allows IPv6 over the low-rate wireless personal area networks. All sensor nodes have their own IPv6 address to connect to Internet. Therefore, the challenge of implementing secure communication in the Internet of Things must be addressed. There are various attack in 6LoWPAN, such as Denial-of-service, wormhole and selective forwarding attack methods. And the Dos attack method is one of the major attacks in WSN and 6LoWPAN. The sensor node’s energy will be exhausted by these attacks due to the battery power limitation. For this reason, security has become more important in 6LoWPAN. In this paper, we proposed a lightweight intrusion detection model based on analysis of node’s consumed in 6LowPAN. The 6LoWPAN energy consumption models for mesh-under and route-over routing schemes are also concerned in this paper. The sensor nodes with irregular energy consumptions are identified as malicious attackers. Our simulation results show the proposed intrusion detection system provides the method to accurately and effectively recognize malicious attacks.

Recently, more and more wireless networks have been deployed and start provide varies services to customers. Such as smart-phones integrate heterogeneous wireless devices, it may cause unintended interactions between multiple radios using difference radio access technologies. Thus, heterogeneous wireless network will be the trend of future network. The Co-channel interference problem in heterogeneous wireless networks is more and more important. This paper focus on the coexistence problem between IEEE 802.11b/g/n and IEEE 802.15.4 protocols in the ISM 2.4 GHz band. The performance impact on IEEE 802.15.4 network under IEEE 802.11 wireless network has been analysis, and results show that IEEE 802.15.4 has serious collision problem if there has no appropriate scheduling mechanisms among two wireless protocols. A CIFS (Coexistence Inter-Frame Space) has been proposed in this paper to effectively enhance the IEEE 802.15.4 transmission probability which is implemented in IEEE 802.11 nodes to observe the transmission opportunity for IEEE 802.15.4 under wireless coexistence environment.

The wireless sensor network (WSN) technology has been one of the most active research topics in the last several years. Besides sensing the environmental or physical data, there has been a growing need on supporting voice communication, particularly under emergency conditions, in WSNs. In this paper, we will conduct the implementation of voice codec on embedded system using multi-hopping ZigBee communication. The implementation issues, in terms of codec and transmission rate-dependence consideration, as well as the voice quality with multi-hopping are analyzed and evaluated for the designed test-bed.

In this paper, we extend the routing enhanced MAC (RMAC) protocol to combine wireless sensor network (WSN) technology with energy-efficiency and quality of service (QoS) guarantee transmission scheduling mechanisms. This energy-efficient QoS-aware scheduling over multi-hopping WSNs is called adaptive multi-hopping MAC (AMH-MAC). Based on the RMAC scheme, we further adjust the transmitted power and the number of multi-hopping nodes dynamically to reduce the transmission latency and energy consumption. We conduct the simulation using network simulator 2 (ns-2) to show the improvement of the performance in terms of end to end latency and energy consumption as compared with RMAC scheme.

The design and implementation of healthcare system using sensor network technology has been one of the most active research topics currently. The research on wireless sensor network mostly focuses on energy saving, such as duty cycle scheduling, and path routing, such as routing protocol for low power and lossy networks (RPL) which however only takes into account a single metric, reliability or energy, as routing decision. If RPL only considers the reliability metric, nodes will suffer from uneven energy. If it only considers the energy metric, nodes will suffer from the rise of packet loss ratio. In this paper, we propose an energy-oriented routing mechanism to improve RPL routing protocol by combining the expected transmission count (ETX) and remaining energy metrics. The simulation will be conducted to analyze the performance of the proposed mechanism.

6L0WPAN is an IPv6 adaptation layer that defines Internet Protocols over low power, low data rate devices such as IEEE 802.15.4. It is difficult to implement because the size of IPv6 packet is much larger than the packet size of IEEE 802.15.4 data link layer. In order to solve this problem, the IETF 6LoWPAN working group introduces the adaptation layer between network and data link layers. It provides header compression to reduce transmission overhead, fragmentation and reassembly of IPv6 packet. In addition, the routing schemes in 6LoWPAN can be divided into two categories: mesh-under and route-over. The main difference between these two schemes depends on how the packets or fragments are processed before being forwarded. In this paper, we present an analysis between these two routing schemes and comparing their IP packet successful transmission probabilities. Moreover, while the number of competing nodes increases, the probability of successful transmission will decrease due to the CSMA/CA mechanism.

Location-based service is one of important application for Wireless Sensor Networks (WSN). Most location information mainly depends on the Receiver Signal Strength (RSS) to estimate the distance between the reference node and the location unknown node. However, the multipath fading and co-channel interference in 2.4GHz ISM-band will affect the accuracy of the position estimation in wireless sensor networks. In this paper, the effect of distance error in error-prone channel condition has been investigated. A secant Location Estimation Scheme (SLES) is proposed to improve the accuracy of the position estimation in error-prone channel condition. The simulation results show the proposed algorithm is accurate and effective.

Location estimation for object tracking is one of the important topics in the research of wireless sensor networks (WSNs). Recently, many location estimation or position schemes in WSN have been proposed. In this paper, we will propose the procedure and modeling of location estimation for object tracking in WSN. The designed modeling is a simple scheme without complex processing. We will use Matlab to conduct the simulation and numerical analyses to find the optimal modeling variables. The analyses with different variables will include object moving model, sensing radius, model weighting valueα, and power-level increasing ratiokof neighboring sensor nodes. For practical consideration, we will also carry out the shadowing model for analysis.

Innovative device designs were used to fabricate low leakage ferroelectric BaTiO3 (BTO) thin film capacitors. BTO thin films with thicknesses ranging from 220 nm to 265 nm were deposited using reactive r.f. magnetron sputtering. A highly stable and conductive metallic oxide, RuO2, was used as the bottom electrode of the capacitors on SiO 2 Si substrates. Layers of BTO deposited at low temperature were amorphous and those deposited at high temperature above 600 °C were polycrystalline. Microcrystallization of amorphous BTO took place at a thermal treatment temperature of above 600 °C. Capacitors with a bilayer configuration of polycrystalline layers on microcrystalline layers showed a capacitance per unit area of around 2.4 × 105pF cm−2 and a leakage current density of (8.5 ± 0.5) × 10 −8 A cm −2 at a field intensity of 2 × 10 5 V cm −1 . A capacitance per unit area of around 1.4 × 10 5 pF cm −2 and a leakage current density of around 10−10A cm−2at a field intensity of 2 × 10 5 V cm −1 were achieved on the capacitors with a nanolayer configuration of amorphous layers on a number of stacked cycles of polycrystalline layers on microcrystalline layers.

Ferroelectric BaTiO3 thin films were deposited on Si by rf magnetron sputtering. A conductive oxide, RuO2, was used as the bottom electrode of the capacitors. The performance of the thin film capacitors was found to be a strong function of the surface and interface properties between ferroelectric BaTiO3 and the bottom electrode. A suitable capacitor configuration must be used to preserve the bottom electrode, to enhance the dielectric constant, and to reduce the leakage current density of the films. BaTiO3 thin film on the RuO2/Si substrate, where the BaTiO3 thin film has a bilayer structure of polycrystalline on microcrystalline, showed a dielectric constant of 125 at a frequency of 1 MHz, leakage current density of 10−6 A/cm2 at a field intensity of 2.5 × 105 V/cm, and a breakdown voltage above 106 V/cm.

Ferroelectric BaTiO3 thin films were deposited on single crystal Si substrates by radio-frequency magnetron sputtering. Bilayer structures of BaTiO3 thin films, either amorphous on polycrystalline (A/P) or polycrystalline on microcrystalline (P/M), were utilized to reduce the leakage current and to enhance the dielectric constant of the films compared to single polycrystalline and amorphous layer structures, respectively. Relatively lower charge density, determined by the capacitance-voltage measurement on the capacitors with a configuration of Au/ BaTiO/p-Si/Al, was detected for the BaTiO3 thin film with a structure of P/M. The current-voltage characteristics of the Al/SiO2(~1.8 nm)/p-Si/Al diodes fabricated on the Si after removing BaTiO3 layers gave direct evidence of the preservation of the Si surface crystal by using a P/M instead of a A/P structure. This was further confirmed by the Auger electron spectroscopy analysis on the samples.

Recent research on extending the stream control transmission protocol (SCTP) multi-homing to support concurrent multipath transfer (CMT) has been in progress. The CMT, being capable of simultaneously transferring data chunks over all available paths, possesses the potential to increase the transmission throughput. In this paper, we will modify the Linux kernel SCTP module to implement CMT SCTP. Furthermore, by correlating the receiver window (RWND) extracted from the selective acknowledgement chunk with the data arrival rate from sender applications, we extend the arrival rate dependent (ARD) queuing model to our implemented system, named RWND based ARD-CMT SCTP. Therefore, we can dynamically adjust the transmission weights for different wireless links according to the transmission rate of mobile node and the RWND rate of corresponding node.

The Location-based service on Wireless Sensor Networks, mainly depend on the Receiver Signal Strength (RSS) to measure the distance between the sender and receiver. The location unaware sensor nodes send beacon periodically, which are captured by anchor sensor nodes. However, it is well-known that these systems suffer from big inaccuracy problems because of environmental changes (the ratio of anchor and target). In this paper, a three-dimensional space-based location algorithm in wireless sensor network has been proposed. The proposed Single Mobile Anchor Location (SMAL) scheme uses single flying anchor which equipped a GPS receiver to coordinate itself position in unknown territory. The mobile anchor node is able to calculate the accuracy position of unaware location sensor nodes through the proposed localization measurement flying model in the three-dimensional coordinate system. The simulation results show the accuracy of localization is a major advantage, the average location error rate is only 0.04%.

The IEEE 802.21 framework is a novel standard and the scope of this standard is to optimize and facilitate handover in heterogeneous networks. In this paper, we propose a handover mobility management by using the IEEE 802.21 to solve some handover issues, such as handover delay and packet loss, in homogeneous and heterogeneous networks. By setting certain signal thresholds and probability confidence to trigger the Link Going Down event, the proposed handover mechanism is capable of providing better handover efficiency and reducing the handover delay and possible packet loss during handover. The NS-2 simulation is conducted to verify the performance of our handover mobility management across WLAN and WiMAX heterogeneous networks.

Voice over Internet protocol (VoIP) is a prevalent multimedia application nowadays. For mobile nodes (MNs) using VoIP services in wireless networks, the handoff issues need to be taken into account. Stream control transmission protocol (SCTP) is a potential transport layer protocol with multi-homing and multi-streaming functions. Mobile SCTP with dynamic address reconfiguration (DAR) extends SCTP to mobile wireless network. In this paper, we design and implement a handoff mechanism using multi-homing, DAR and partially reliable SCTP (PR-SCTP) of mobile SCTP to transport VoIP applications. The switch from UDP or TCP to SCTP for VoIP transport provides the seamless handoff ability for MNs using real-time applications such as VoIP service. This paper also provides the performance analyses of the proposed scheme on the implemented Linux testbed.

In wireless sensor networks, energy efficiency is an important research issue. The data transmission times could be decreased effectively to achieve energy efficiency by applying a cluster-based structure. This study proposed a level-based energy efficiency clustering approach. Each cluster replaces its cluster head and re-clusters periodically according to the established energy level. A cluster head is a node that has more residual energy and lower communication cost compared to other nodes. This level-based energy efficiency clustering approach could decrease the replacement times of cluster heads, thus avoiding the excessive energy consumption caused by frequent replacement of cluster heads. The simulation results showed that this approach has less energy consumption and can effectively extend the network lifetime.

Efficiency improvement is important for new transport layer protocols. Stream control transmission protocol (SCTP), proposed by IETF, is to improve the efficiency and security of the transport layer. SCTP is featured by multi-homing and multi-streaming. Though the source and destination nodes exchange the available address list after four-way handshake in the initial stage, the quality of each available link is unknown. Hence, the chosen primary path may not be the best path which implies inefficiency. In this paper, we propose a scheme to add two new chunks which carry the status of each alternative path during the four-way handshake of SCTP. Hence, the path of the best quality will be selected as the primary path. The simulation, by NS2, results show when the best path is selected to transmit data, the throughput could be improved up to 83.3% as compared with the worst case.

It is important to develop the multicasting technology for video on demand (VoD) services in Internet Protocol Television (IPTV) system with multiple channels. In this paper, we proposed an architecture combining multicast and unicast batching channels without scheduled multicasting streams. To provide an acceptable service rate and waiting latency, the 80% multicast channel rate under the experimental scenario is believed to be the optimized allocation between unicast and multicast VoD channels. Depending on the time zone of the arrival and the popularity of the requested videos, the batching scheme with five different time zones was designed to increase the efficient usage of the transmission bandwidth, especially for the request on popular videos, and to reduce the unnecessary waiting latency, especially at cold time zone.

This paper proposes a fixed clustering algorithm (FCA) to improve energy efficiency for wireless sensor networks (WSNs). In order to reduce the consuming energy of sending data at each sensor, the proposed algorithm uniformly divides the sensing area into clusters where the cluster head is deployed in the center of the cluster area. Simulation results show that the proposed algorithm definitely reduces the energy consumption of the sensors and extends the lifetime of the networks nearly more 80% compared to the random clustering (RC).

Mobile SCTP (mSCTP) has been proposed to support transport layer mobility management. In this paper, we proposed a dynamic handover mechanism named Contention-based mSCTP (C-mSCTP) in the contention based wireless network. The handover strategy in C-mSCTP takes wireless bandwidth and the contention probability into account to set the primary path before transmitting data. The simulation results show that the C-mSCTP achieves much better performance in terms of transmission delay and throughput than mSCTP does.

In this paper, we apply the hierarchical concept to the Care-of Prefix (CoP) scheme as HCoP and enhance HCoP with a novel Binding Update Tree (BUT) structure as HCoP-B for NEtwork MObility (NEMO) management of the nested mobile network. As compared to schemes such as Reverse Routing Header (RRH), Route Optimization using Tree Information Option (ROTIO) and HCoP with numerical performance evaluations, HCoP-B achieves the shortest handoff latency and significantly reduces the consumed network bandwidth of global binding update messages for route optimizations (RO) of all correspondent nodes (CN) after the nested mobile network hands over to a new AR. Consequently, HCoP-B resolves the RO storm problem.

Mobile communications will be the major applications of next-generation Internet. The users may access the mobile services using handheld devices anywhere and anytime. Therefore, mobility management will play a significant role in providing mobile multimedia services. Both MIP and SIP have been proposed to solve the IP mobility issues. For the multimedia application such as VoIP, SIP has been studied and widely deployed recently. To process various data with both MIP and SIP protocols, it is necessary to design an efficient multi-layer registration scheme for mobility management and multimedia services. In this paper, we propose an integrated scheme to improve the registration efficiency for mobile nodes carrying out both MIP and SIP protocols. The number of registration message as well as the registration delay will be reduced by using the proposed integrated multi-layer registration scheme.

In this paper, we will propose an area-based vertical motion estimation (AVME) scheme to efficiently and accurately predict target wireless networks and corresponding target cells for the next handoff of the mobile node (MN) on the increasingly prevalent heterogeneous wireless network environment which consisting of several different wireless networks such as wireless LAN (WLAN), third generation cellular network (3G), etc. We adopt the back propagation neural network (BPN) model in this AVME scheme to generate mobility patterns of MNs by training the BPN model with historical handoff information of these MNs. By using the IBM City Simulator [1] to create the city plan and motions of all MNs, simulation results show that our AVME scheme on heterogeneous wireless networks can achieve higher level of predication accuracy for next handoff than traditional cell-based prediction scheme does on a single wireless network, but with less resources and computations.

In this paper, we propose the Hierarchical Multicast Session Initiation Protocol (HMSIP), which integrates the IETF Session Initiation Protocol (SIP) with the IP multicast protocol and the RSVP resource reservation technique, to reduce the handoff delay, deployment cost and support fast handoff for the MH with guaranteed multimedia QoS that the traditional approaches such as the Hierarchical Remote Subscription (HRS) and Bi-directional Tunneling (BT) cannot do. We mathematically analyze handoff delays of the HRS, BT and HMSIP schemes. Finally, we show in simulations that the HMSIP can significantly reduce handoff delays suffered by the HRS and achieve more stable delays than the BT, with a small proportion of extra bandwidth than that of the bandwidth-optimal HRS.

Multicasting technology has been a practical solution for implementing large scale video-on-demand (VoD) system. The major drawback of true VoD systems is cost due to the dedicated transmission channel for every single customer. The tradeoffs of the near VoD system, however, come to the scheduled multicasting streams and limited video selections. A near VoD architecture combining multicasting and unicasting batching is proposed in this research. The dynamic adjustment of the batching time with virtual community is presented to solve the server loading and bandwidth problem. Our proposed schemes are believed to provide several strategies for the realistic implementation of the VoD system.

In this paper, we first apply the hierarchical concept to the care-of prefix (CoP) scheme as HCoP and enhance HCoP with a novel binding update tree (BUT) structure as HCoP-B for network mobility (NEMO) management of the nested mobile network. Second, we further extend HCoP-B to support the seamless handoff of the nested NEMO. As compared to schemes such as reverse routing header (RRH), route optimisation using tree information option (ROTIO) and HCoP with numerical performance evaluations, HCoP-B achieves the shortest handoff latency and significantly reduces the consumed network bandwidth of global binding update messages for route optimisations (RO) of all correspondent nodes (CN) after the nested mobile network hands over to a new AR. Besides, HCoP-B also achieves shorter playback disruption time and buffering time than ROTIO does, which is the only one scheme mentioned how to achieve seamless handoff for the NEMO in the literature, for ongoing real-time multimedia applications whenever the mobile subnet in the old nested mobile network hands over to a new one.

Push-to-talk (PTT) is a walkie-talkie like service which performs an efficient and instant voice over Internet protocol (VoIP) communication in mobile ad hoc network especially for certain circumstances, such as battle field and earthquake or disaster relief. The authors have designed and implemented the PTT mechanism in ad hoc VoIP network. The PTT server and user agent combined with the pseudo session initiation protocol (SIP) server in the implementation provide the PTT service without standalone SIP server support. The authors also conduct the experimental measurements, in terms of delay and packet loss, in the test-bed to demonstrate the realisation of PTT service in ad hoc VoIP network.