Novel SVC bit-stream distribution alogrithm over wireless network

Blockchain technology is finding applications in wireless networks, in particular vehicular networks, for the purposes of establishing trust. A certain set of network resources in terms of communication and computation requirements is also necessary for successful blockchain deployment. Moreover, heterogeneity in wireless networks and changing radio conditions at the physical layer, make it even more challenging to guarantee steady block generation latency. In this work, we study the possible denial of blockchain service attacks where malicious nodes threaten to slow down the block generation latency. We propose a novel Proof-of-Communication-Capability (PoCC) authentication framework that acts as a defense against communication capability spoofing over wireless networks. Our PoCC authentication framework utilizes physical properties such as distance between nodes, channel state information (CSI), and communication puzzle latency to establish the communication capabilities of nodes in the wireless network. Results from a simulated AV network under three different variations of the proposed PoCC framework are encouraging and demonstrate that such attacks can be effectively mitigated.

Over the last couple of years, the recent pandemic rendered work operations to be mobile and relied heavily on real-time and traffic-intensive applications such as online classrooms and meetings. Since our working life requires seamless mobility and stable wireless connectivity, heterogeneous wireless networks gain more attention as key infrastructures to fulfill communication needs. Intelligent handover decision deems necessary to select the appropriate wireless network. An intelligent mechanism such as fuzzy logic proves to enhance such decision-making. Different membership functions used in a fuzzy inference system contribute to different network selection performances. This work evaluates different fuzzy membership functions, hence appropriate membership functions can be used in the design of fuzzy-based network selection mechanisms for heterogeneous wireless networks.

In this paper we investigate the impact of a Relay Node (RN) placement plan on a heterogeneous wireless network called Hybrid Wireless Network with dedicated delay nodes (HWN*) in terms of system capacity, transmission delay and Quality of Service (QoS). A novel HWN* Heuristic RN Placement (HHRP) algorithm, which considers RN assistance & support for radio resource sharing such as inter-network traffic balancing, TD/CDMA soft handover, routing and user mobility has been implemented. A system level simulation is used to quantify the benefits of HWN* using HHRP algorithm over HWN* with other RN placement plans and multi-hop cellular networks. I. INTRODUCTION A heterogeneous wireless network refers to a wireless net- work that is comprised of wireless nodes with different radio access technologies or equipment with different operating systems. For example, it can be a wireless sensor network including bluetooth based radio access and zigbee 802.15.4 based radio access or a hybrid wireless network including cellular access and 802.11b/g based radio access. Specifi- cally for a hybrid wireless network, the increase of cellular communication intensity results in a reduction in cell size, thus much denser clusters are required resulting in increased infrastructure cost and system complexity. Meanwhile, the bursty nature of communication traffic and path loss results in traffic prediction difficulty. A solution must be found to provide effective resource management, congestion control and routing. The hybrid wireless network which incorporates cellular and MANET interfaced RELAY nodes, provides a practical approach for this. Nevertheless, the dedicated relay infrastructure approach can be also be adapted to the emerging wireless sensor network in order to maintain node connectivity, support sensor data aggregation and optimise power consump- tion.

In this paper, we investigate the video stream distributed transmission problem for the emergency communication over heterogeneous wireless networks. The key issue of the transmission problem is how to guarantee the quality of service, when the video stream is transmitted by multiple wireless access networks. According to observed available bit rate (ABR) and round trip time (RTT) over each access network, we propose four distributed rate allocation algorithms with different optimization objectives, in term of the average packet loss rate, the maximum delay, the proportional fairness and the benefit fairness of networks. Simulation results show that these four proposed algorithms can perform well both in fairness and effectiveness. Furthermore, the video distortion minimization algorithm and the maximum delay minimization algorithm tend to be more practical since the video quality is important in the emergency communication.

To achieve an optimum transmission over a noisy wireless channel, both the source coding and network should be jointly adapted. An acceptable video quality in wireless environ‐ ment can be obtained by the adjustment of parameters in video codec and wireless network. For the former, people have proposed many error resilient video encoding algorithms to en‐ hance the robust performance of the compressed video stream in wireless networks. These algorithms can be divided into three categories: 1) error detection and error concealment al‐ gorithms used at video decoder of wireless receiver; 2) error resilient video encoding algo‐ rithms located at video encoder of wireless transmitter; 3) robust error control between video encoder and decoder based on 1) and 2). Fig.1 summarizes different techniques at dif‐ ferent parts of a wireless video transmission system.

Particle swarm optimization application for multiple attribute decision making in vertical handover in heterogenous wireless networks

Heterogeneous wireless network (HWN) is an overlay structure of different wireless networks (WN). The WNs may differ in terms of coverage, capacity, underlying technology, service types, and network operators. In such a HWN environment, a mobile user (MU) equipped with multi-mode or multi-home terminal always wish to maintain connectivity with a wireless network which can provide best quality of experience (QoE). Similarly, the WN may allow the connectivity only to a MU which can provide highest revenue. This may leads to an event, called vertical handoff, where the MU leaves current WN and connect to another different WN. The conflicting goals of maximizing QoE and revenue simultaneously while performing a VHO necessitates the selection of mutually best MU and WN. Game theory is an efficient mathematical tool to model such situations where specific actions of decision makers lead to mutually conflicting consequences to each other. This paper, using a tutorial style, presented the game theory concepts and its application for VHO, type of games, and game solutions. It proposes, in specific, the noncooperative game formulations for three different VHO situations and their solutions using NASH for HWNs.

A new multi-rat scheduling algorithm for heterogeneous wireless networks

The wireless network environment in the future is going to include various heterogeneous wireless networks. In a heterogeneous wireless network environment, vertical handoff processes caused by the movement of users are inevitable. However, the research related to how to achieve seamless vertical handoff and improve QoS guarantees in today's heterogeneous wireless networks is still something to work on. Therefore, this paper proposed the Advanced Vertical Handoff Translation Center (Advanced VHTC) architecture for Wi-Fi/WiMAX heterogeneous wireless networks, aiming to improve the quality of services in heterogeneous wireless networks by means of packet formats translation between heterogeneous wireless networks and the MIH-based seamless vertical handoff mechanism, which cut down the time for vertical handoff and obtain high quality and persistent connection service. Lastly, with the brilliant results of a complete simulation, this paper will show the performance in terms of delay, jitter, packets loss and throughput to prove that the Advanced VHTC for next generation heterogeneous wireless networks can provide good QoS guarantees and obtain persistent transmission with high performance while performing seamless vertical handoff.

In this work, we propose a cross-layer optimized multipath video streaming system over heterogeneous wireless networks. The proposed system uses multiple paths over wireless mobile networks in order to satisfy the quality-of-service requirements for seamless high-quality video streaming services and adopts fountain codes to handle the effect of lost packets over wireless networks efficiently. Moreover, a cross-layer approach is used to determine the code rate of fountain codes efficiently. Finally, the proposed system is implemented and tested in real environments.

Future-generation wireless networks have been envisioned as the integration of various wireless access networks, including both wireless wide area networks and wireless local area networks. In such a heterogeneous network environment, seamless mobility support is the basis of providing uninterrupted wireless services to mobile users roaming between various wireless access networks. Because of transparency to lower-layer characteristics, ease of deployment, and greater scalability, the application-layer-based session initiation protocol has been considered the right candidate for handling mobility in heterogeneous wireless networks. However, SIP entails application-layer transport and processing of messages, which may introduce considerable delay. As a case study of the performance of mobility management protocols in the heterogeneous wireless networks, we analyze the delay associated with vertical handoff using SIP in the WLAN-UMTS internetwork. Analytical results show that WLAN-to-UMTS handoff incurs unacceptable delay for supporting real-time multimedia services, and is mainly due to transmission of SIP signaling messages over erroneous and bandwidth-limited wireless links. On the other hand, UMTS-to-WLAN handoff experiences much less delay, mainly contributed by the processing delay of signaling messages at the WLAN gateways and servers. While the former case requires the deployment of soft handoff techniques to reduce the delay, faster servers and more efficient host configuration mechanisms can do the job in the latter case.

This paper presents the study of the hyper-Erlang distribution model and its applications in wireless networks and mobile computing systems. We demonstrate that the hyper-Erlang model provides a very general model for users' mobility and may provide a viable approximation to fat-tailed distribution which leads to the self-similar traffic. The significant difference from the traditional approach in the self-similarity study is that we want to provide an approximation model which preserves the Markovian property of the resulting queueing systems. We also illustrate that the hyper-Erlang distribution is a natural model for the characterization of the systems with mixed types of traffics. As an application, we apply the hyper-Erlang distribution to model the cell residence time (for users' mobility) and demonstrate the effect on channel holding time. This research may open a new avenue for traffic modeling and performance evaluation for future wireless networks and mobile computing systems, over which multiple types of services (voice, data or multimedia) will be supported.

It is envisaged that next generation wireless networks (NGWN) will be heterogeneous, consisting of multiple radio access technologies (RATs) coexisting in the same geographical area. In these heterogeneous wireless networks, mobile terminals of different capabilities (heterogeneous terminals) will be used by subscribers to access network services. We investigate the effect of using heterogeneous mobile terminals (e.g. single-mode, dual-mode, triple-mode, etc.) on call blocking and call dropping probabilities in cooperative heterogeneous wireless networks. We develop analytical models for heterogeneous mobile terminals and joint radio resource management in heterogeneous wireless networks. Using a two-class three-RAT heterogeneous wireless network as an example, the effect of using heterogeneous terminals in the network is evaluated. Results show the overall call blocking/dropping probability experienced by subscribers in heterogeneous wireless networks depends on the capabilities of mobile terminals used by the subscribers. In the worst case scenario, when all subscribers use single-mode mobile terminals, each subscriber is confined to a single RAT and consequently, joint radio resource management in heterogeneous wireless network has no improvement on new call blocking and handoff call dropping probabilities. However, in the best case scenario, when all subscribers use three-mode terminals, new class-1 call blocking probability decreases from 0.37 (for 100% single-mode terminals) to 0.05, at the arrival rate of 6 calls per minute. New class-2 call blocking probability also decreases from 0.8 to 0.52. Similarly, handoff class-1 call dropping probability decreases from 0.14 to 0.003, and handoff class-2 call dropping probability decreases from 0.44 to 0.09.

Many studies have shown that Vegas TCP has a better throughput and stability than Reno TCP in homogeneous networks with a single TCP flavor, but performs less well in heterogeneous networks in which two TCP flavors coexist. The progressive behavior of Reno TCP and the conservative behavior of Vegas TCP cause a bias when they are used simultaneously, and thus Vegas TCP fails to obtain a fair share of the bandwidth. This paper examines the origins of this bias and proposes a threshold-based congestion control mechanism designed to alleviate the resulting unfairness problem. The simulation results show that the proposed scheme achieves a higher throughput than the conventional Vegas TCP scheme and preserves the stability of the conventional scheme when used in heterogeneous wired and wireless networks.

We first develop a rate-distortion (R-D) model for DCT-based video coding incorporating the macroblock (MB) intra refreshing rate. For any given bit rate and intra refreshing rate, this model is capable of estimating the corresponding coding distortion even before a video frame is coded. We then present a theoretical analysis of the picture distortion caused by channel errors and the subsequent inter-frame propagation. Based on this analysis, we develop a statistical model to estimate such channel errors induced distortion for different channel conditions and encoder settings. The proposed analytic model mathematically describes the complex behavior of channel errors in a video coding and transmission system. Unlike other experimental approaches for distortion estimation reported in the literature, this analytic model has very low computational complexity and implementation cost, which are highly desirable in wireless video applications. Simulation results show that this model is able to accurately estimate the channel errors induced distortion with a minimum delay in processing. Based on the proposed source coding R-D model and the analytic channel-distortion estimation, we derive an analytic solution for adaptive intra mode selection and joint source-channel rate control under time-varying wireless channel conditions. Extensive experimental results demonstrate that this scheme significantly improves the end-to-end video quality in wireless video coding and transmission.