Low Packet Research Articles

Real-Time Link-Reliability Routing for QoS in Wireless Sensor Networks

This paper proposes a Real-Time Link Reliability Routing protocol for wireless sensor networks (WSNs). The protocol achieves to reduce packet deadline miss ratio while considering link reliability, two-hop velocity and power efficiency and utilizes memory and computational effective methods for estimating the link metrics. Numerical results provide insights that the protocol has a lower packet deadline miss ratio and improved sensor network lifetime. The results show that the proposed protocol is a feasible solution to the QoS routing problem in wireless sensor networks that support real-time applications.

와이맥스 메쉬 네트워크에서 LSQR 스케줄링을 이용한 QoS 라우팅 성능 향상에 관한 연구

Recently, wireless mesh network has been focused as a core technology for resolving the issues of shadow zone and distributed bypass route as it has broad service coverage as well as good scalability features. It, however, provides users with relatively lower QoS than infrastructure-based networks. In order for addressing this QoS issue and also enhancing the routing performance of mobile WiMax mesh network, this paper proposes a load sensing QoS routing (LSQR) scheme. In the proposed LSQR, each node figures out network congestion status and selects a bypass route accordingly. With this scheme, we can expect good load balancing effect by changing the routing paths from centralized links to distributed links under a heavy traffic condition. From the simulation results using NS-2, it has been verified that the LSQR shows lower packet loss rates and data transmission delays than the existing representative routing schemes.

High-Speed Multicast Scheduling in Hybrid Optical Packet Switches with Guaranteed Latency

In this paper, we study multicast scheduling in the OpCut switch, a recently proposed hybrid optical/electronic switching architecture for transmitting high-volume traffic in core networks and parallel computers. First, we present a multicast scheduling algorithm called Guaranteed Latency Multicast Scheduling (GLMS) that considers the schedule of each packet for multiple time slots. We show that GLMS has several desirable features, such as guaranteed latency for all transmitted packets and adaptivity to transmission requirements. To relax the time constraint on computing a schedule, we further propose a parallel and pipeline processing architecture for GLMS that distributes the scheduling task to multiple pipelined processing stages, with N processors in each stage, where N is the switch size. Finally, by implementing it with simple combination logic circuits, we show that each processor can finish the scheduling for one time slot in (O(1)time complexity. We evaluate the performance of GLMS extensively against statistical traffic models and real Internet traffic, and the results show that the proposed GLMS algorithm can achieve very low average packet latency with minimum packet drop ratio.

Best-retransmission count selection for environment optimization over wireless heterogeneous networks

This paper proposes an environment-aware best-retransmission count selected optimization control scheme over IEEE 802.11 multi-hop wireless networks. The proposed scheme predicts the wireless resources by using statistical channel state and provides maximum retransmission count optimization based on wireless channel environment state to improve the packet delivery success ratio. The media access control (MAC) layer selects the best-retransmission count by perceiving the types of packet loss in wireless link and using the wireless channel characteristics and environment information, and adjusts the packet forwarding adaptively aiming at improving the packet retransmission probability. Simulation results show that the best-retransmission count selected scheme achieves a higher packet successful delivery percentage and a lower packet collision probability than the corresponding traditional MAC transmission control protocols.

Inter-Network Cooperation Exploiting Game Theory and Bayesian Networks

Relay sharing has been recently investigated to increase the performance of coexisting wireless multi-hop networks. In this paper, we analyze a scenario where two wireless ad hoc networks are willing to share some of their nodes, acting as relays, in order to gain benefits in terms of lower packet delivery delay and reduced loss probability. Bayesian network analysis is exploited to compute the probabilistic relationships between local parameters and overall performance, whereas the selection of the nodes to share is made by means of a game theoretic approach. Our results are then validated through the use of a system level simulator, which shows that an accurate selection of the shared nodes can significantly increase the performance gain with respect to a random selection scheme.

A Betweenness Calibration Topology Optimal Control Algorithm for Wireless Sensor Networks

In self-organized wireless sensor networks (WSNs), any two sensor nodes can connect if they are placed in each other's communication range. Therefore, the physical topology of WSNs is usually a strongly connected topology. Sensor nodes should frequently receive and process data from their large number of neighbors, which will consume great amounts of energy. Shocking wireless channel collision also causes low throughput and high loss packets ratio during data transmission. To improve the transmission performance and save scarce energy, a logical topology generating from the physical one is necessary for the self-organized WSNs. Based on the complex network theory, this paper proposed a novel betweenness addition edges expansion algorithm (BAEE). With betweenness calibration, BAEE algorithm expanded the minimum-cost edges to optimize the network topology. Two performance metrics-connectivity functions, robustness function [Formula: see text] and efficiency function [Formula: see text], were utilized to evaluate the network capability of the robustness and invulnerability. [Formula: see text] is the parameter to measure the topology connectivity, and [Formula: see text] is the parameter to evaluate the network exchanging information capability. Based on the simulation under various random failures and intentional attack scenarios, BAEE can effectively optimize WSNs' topology and improve the network's robust connectivity and extremely efficient exchanging information capability.

Voice Service Solutions in Evolved Packet System

EPS network is the future direction of mobile network, and voice service is still important in the EPS network. In the conventional 2G/3G mobile communication, voice service is provided by circuit switching in the CS domain. As the LTE core network provides the access to high-speed and lower latency wireless packet data on the air interface 3GPP retains the PS domain rather than the CS domain in designing the core network. And voice service which is included in the packet domain is available through VOIP. To ensure high-quality voice services, 3GPP proposes two solutions: CSFB and SRVCC. Each option has its own applied conditions, advantages and disadvantages. This article first introduces EPC network framework and the functions of its core functional entities. Then the network framework and voice processing of the two programs (CSFB and SRVCC) are compared. At last, a conclusion of advantages and disadvantages of the two programs is given, and it will lay the basis for different options.

Dynamic Bandwidth Allocation Algorithm With Proper Guard Time Management Over Multi-OLT PON-Based Hybrid FTTH and Wireless Sensor Networks

A passive optical network (PON) is a highly capable access network that effectively converges several service providers, without suffering from any bandwidth deficiency. However, a PON consisting of a single optical line terminal (OLT) for multiple service providers increases the computational complexity for data packet processing in the OLT, resulting in a longer time delay and more packet loss. A multi-OLT PON-based access network is an effective solution for reducing the computational complexity of data packet processing in a hybrid network of multiple service providers. The most important issue concerning the multi-OLT PON is the sharing efficiency of upstream channels among multiple service providers having different packet lengths and data rates. In this paper, we propose a dynamic bandwidth allocation algorithm called adaptive limited dynamic bandwidth allocation for multi-OLT PON (ALDBAM). The proposed scheme is a modified version of adaptive limited dynamic bandwidth allocation (ALDBA) algorithms that we proposed before, where both the ALDBA1 and ALDBA2 schemes are combined with proper guard time management and a modified multipoint control protocol. The simulation results show that the ALDBAM scheme provides lower packet delay with higher bandwidth utilization, higher upstream efficiency, and higher throughput than the conventional ALDBA1 and ALDBA2 schemes.

The end-to-end QoS guarantee framework for interworking WiMAX PMP and mesh networks with Internet

A network environment, in which 802.16 WiMAX PMP and mesh networks interwork with the Internet, is becoming prevalent and thus ensuring an end-to-end QoS of a media stream after the handoff of mobile host is critical. In this paper, an end-to-end QoS guarantee framework and its handoff flows are revised first. An end-to-end QoS adjustment algorithm is proposed to dynamically adjust the L2 bandwidth allocated in the WiMAX PMP and mesh networks and the L3 data rate in the Internet after the handoff. A CBQ+RED QoS adaptation algorithm is further proposed to adapt queue lengths among different service types and provide efficient queue and traffic management mechanisms as each packet arrives. Finally, simulation results indicate that this framework with these two algorithms outperform three QoS management schemes by supporting higher throughputs, lower packet loss ratios and smaller delays on the end-to-end path under different parameter combinations and two handoff scenarios.

Latency and Reliability-aware Geographic Routing for Mobile Wireless Sensor Networks

The mobility and energy scarcity are two main challenges of efficient routing in mobile wireless sensor networks (WSNs). However, messages should be reliably transported to the Sink with low latency in many application scenarios. To accomplish this, a hierarchical routing scheme, Latency and Reliability-aware Geographic Routing (LRGR), is proposed. Firstly, the cluster is formed considering node mobility and residual energy to tackle with the dynamic network topology and constrained energy. To ensure inter-cluster routing, several key ingredients are developed, such as indirect communication amongst adjacent cluster heads using their common gateways, aggregate path metric based on the connectivity, geographical position, residual energy and sojourn time of adjacent cluster heads. Simulation results demonstrate that LRGR can enhance the network lifetime while has lower latency and packet loss ratio when compared to VIBE.

A seamless flow mobility management architecture for vehicular communication networks

Vehicular ad-hoc networks (VANETs) are self-organizing, self-healing networks which provide wireless communication among vehicular and roadside devices. Applications in such networks can take advantage of the use of simultaneous connections, thereby maximizing the throughput and lowering latency. In order to take advantage of all radio interfaces of the vehicle and to provide good quality of service for vehicular applications, we developed a seamless flow mobility management architecture based on vehicular network application classes with network-based mobility management. Our goal is to minimize the time of flow connection exchange in order to comply with the minimum requirements of vehicular application classes, as well as to maximize their throughput. Network simulator (NS-3) simulations were performed to analyse the behaviour of our architecture by comparing it with other three scenarios. As a result of this work, we observed that the proposed architecture presented a low handover time, with lower packet loss and lower delay.

Toward Optimized Traffic Distribution for Efficient Network Capacity Utilization in Two-Layered Satellite Networks

A multi-layered satellite network (MLSN) appears to be a promising network for providing global ubiquitous broadband communication. To utilize the abundant network resources of the MLSNs, fair traffic distribution among its satellite layers is, indeed, important. In this paper, we propose a routing method to optimally distribute traffic load among the layers (i.e., the satellite layers in the MLSN). The load balancing scheme of the proposed routing method is developed by adopting a traffic distribution model, which is based upon network capacity estimation and theoretical analysis of the congestion rate in each layer. The performance of the proposed routing method has been validated through extensive computer simulations, which demonstrate that our traffic distribution model is reliable enough to characterize the traffic behavior in the MLSN. Furthermore, in contrast with the basic routing approach, our proposed routing method is more effective in terms of improved throughput and lower packet drops, which are optimized by the theoretical parameter setting.

Investigation on uplink collaborative contention-based bandwidth request for WiMAX three hop relay networks

This paper suggests a collaborative contention bandwidth request (BR) mechanism for worldwide interoperability for microwave access (WiMAX) three-hop relay networks. By complimenting message and code BR in three hops of a link, the proposed framework enables low block error rate (BLER), packet dropping and signaling overhead while preserving the connection throughput and access delay requirements of best effort (BE) services. With three hops between base station (BS) and mobile station (MS) via relay station 1 (RS1) and relay station 2 (RS2), there take place eight possible BR mechanisms with message and code BR. Among eight BR mechanisms, message-message-code (MMC) BR performs better with message dominant BR and code-message-code (CMC) BR performs better with code dominant BR. Further, with CMC BR, the BLER is reduced by 5.88%, packet dropping is reduced by 8.68%, medium access control (MAC) overhead is reduced by 7.6%, MAC wastage is reduced by 4.47%, connection delay is reduced by 28.30%, queuing delay is reduced by 8.65%, queue size is reduced by 15.25% and throughput is improved by 11.51% than MMC BR mechanism.

A hybrid reservation-based MAC protocol for underwater acoustic sensor networks

Due to the characteristics of underwater acoustic channel, such as long propagation delay and low available bandwidth, media access control (MAC) protocol designed for the underwater acoustic sensor network (UWASN) is quite different from that for the terrestrial wireless sensor network. However, for the contention-based MAC protocols, the packet transmission time is long because of the long preamble in real acoustic modems, which increase the packet collisions. And the competition phase lasts for long time when many nodes are competing for the channel to access. For the schedule-based MAC protocols, the delay is too long, especially in a UWASN with low traffic load. In order to resolve these problems, a hybrid reservation-based MAC (HRMAC) protocol is proposed for UWASNs in this paper. In the proposed HRMAC protocol, the nodes reserve the channel by declaring and spectrum spreading technology is used to reduce the collision of the control packets. Many nodes with data packets to be transmitted can reserve the channel simultaneously, and nodes with reserved channel transmit their data in a given order. The performance analysis shows that the proposed HRMAC protocol can improve the channel efficiency greatly. Simulation results also show that the proposed HRMAC protocol achieves better performance, namely higher network throughput, lower packet drop ratio, smaller end-to-end delay, less overhead of control packets and lower energy overhead, compared to existing typical MAC protocols for the UWASNs.

Ant Colony with Colored Pheromones Routing for Multi Objectives Quality of Services in WSNs

In this article, we present a new Ant-routing algorithm with colored pheromones and clustering techniques for satisfying users’ Quality of Service (QoS) requirements in Wireless Sensor Networks (WSNs). An important problem is to detect the best route from a source node to the destination node. Moreover, it is considered that the feature of non-uniformly distributed traffic load and possibility existing of the traffic requiring various performances; therefore, it is assumed the different class of traffic required for QoS of communication. In this paper, novel protocol, the suitability of using meta-heuristic an ant colony optimization based on energy saving and multi objectives, the demand of QoS routing protocol for WSN will be very adaptive ,resident power and mainly decrease end-to-end delay. These metrics are used by colored pheromones adapted to the traffic classes. Moreover, we reinforce the proposed method for scalability issue by clustering techniques. We use a proactive route discover algorithms in clusters and reactive discovery mechanism between different clusters. Compared to existing QoS routing protocols, the novel algorithm has been designed for various service categories such as real time (RT) and best effort (BE) traffic, resulted lower packet deadline miss ratio and higher energy efficiency and better QoS and longer lifetime..

Improving Packet Delivery Performance of Publish/Subscribe Protocols in Wireless Sensor Networks

MQTT-S and CoAP are two protocols able to use the publish/subscribe model in Wireless Sensor Networks (WSNs). The high scalability provided by the publish/subscribe model may incur a high packet loss and therefore requires an efficient reliability mechanism to cope with this situation. The reliability mechanism of MQTT-S and CoAP employs a method which defines a fixed value for the retransmission timeout (RTO). This article argues that this method is not efficient for deploying publish/subscribe in WSN, because it may be unable to recover a packet, therefore resulting in a lower packet delivery ratio (PDR) at the subscriber nodes. This article proposes and evaluates an adaptive RTO method, which consists in using a Smooth Round-trip Time and multiplying it by a constant parameter (K). Thanks to this method, the reliability mechanism of MQTT-S and CoAP would be able to react properly to packet loss and would also be lightweight in terms of energy, memory and computing for sensor nodes where these resources are critical. We present a detailed evaluation of the effects of the K value on the calculation of the adaptive RTO method. We also establish the setting for obtaining the highest PDR on the subscriber nodes for single-hop and multi-hop scenarios. The results for single-hop scenario show that use of the appropriate K value for the adaptive RTO method increases the PDR up to 76% for MQTT-S and up to 38% for CoAP when compared with the use of fixed RTO method for both protocols, respectively. Meanwhile the same comparison for multi-hop scenario, the adaptive RTO method increases the PDR up to 36% for MQTT-S and up to 14% for CoAP.

Design and Evaluation of a Cross-Layer Framework for Improving 802.11 Networks

This paper reports on the design and evaluation of a class of cross-layer design (CLD) framework for improving the performance of 802.11-based wireless local area networks (WLANs). While various CLD approaches have been proposed for improving the performance of WLANs in recent years, the problem of efficient channel utilization, higher throughput, lower packet delay, and fairness has not been fully solved yet. To overcome the performance problems of 802.11, we propose a CLD framework which is based on a cross-layer medium access control (MAC) protocol called the channel-aware buffer unit multiple access (C-BUMA). In the framework, the radio propagation (i.e. physical layer) is combined with the MAC sub-layer to develop a robust cross-layer communication. By sharing channel information with the MAC protocol, the approach reduced unnecessary packet transmissions, and hence reduced bandwidth wastage and significantly improved the system performance. The proposed CLD method is evaluated by extensive simulation experiments. A comparison with 802.11 standards is provided. Results obtained show that the network achieves up to 13.5% higher throughput, 56% lower packet delay, 40% better fairness, and 38% lower packet dropping with the proposed CLD. We also found that the proposed CLD outperforms Pham’s CLD with respect to network throughput and packet dropping. The analysis and empirical results reported in this paper provide some insights into the design and evaluation of a CLD framework for improving data rate of 802.11 networks which may help researchers in this field to overcome the remaining design issues and challenges.

Robust On-Demand Multipath Routing with Dynamic Path Upgrade for Delay-Sensitive Data over Ad Hoc Networks

Node mobility in mobile ad hoc networks (MANETs) causes frequent route breakages and intermittent link stability. In this paper, we introduce a robust routing scheme, known as ad hoc on-demand multipath distance vector with dynamic path update (AOMDV-DPU), for delay-sensitive data transmission over MANET. The proposed scheme improves the AOMDV scheme by incorporating the following features: (i) a routing metric based on the combination of minimum hops and received signal strength indicator (RSSI) for discovery of reliable routes; (ii) alocal path updatemechanism which strengthens the route, reduces the route breakage frequency, and increases the route longevity; (iii) akeep alivemechanism for secondary route maintenance which enables smooth switching between routes and reduces the route discovery frequency; (iv) apacket salvagingscheme to improve packet delivery in the event of a route breakage; and (v) low HELLO packet overhead. The simulations are carried out in ns-2 for varying node speeds, number of sources, and traffic load conditions. Our AOMDV-DPU scheme achieves significantly higher throughput, lower delay, routing overhead, and route discovery frequency and latency compared to AOMDV. For H.264 compressed video traffic, AOMDV-DPU scheme achieves 3 dB or higher PSNR gain over AOMDV at both low and high node speeds.

Gray Relevance Algorithm Based Routing Protocol in Ad Hoc Network

The characteristics of nodes moving arbitrarily and the network topology changing frequently lead to AODV routing protocol, which uses minimum hop-count as the metric for route selection, facing intermittent connectivity frequently which would cause QoS of network degradation in Ad Hoc Network. In this paper, we integrate three cross layer infor-mation which consists of the remaining energy of nodes, the remaining queue length and the hop-count from source node to destination node. Then we present the GRA-AODV routing protocol based on the gray relevance algorithm. By comparing the simulation and experimental results, in the case of slightly increase in routing overhead, the improved Gray Relevance Algorithm-AODV routing possesses lower average end to end delay and lower packet loss rate, and it has superior robustness in the mobile Ad Hoc Network with network topology changing frequently.

Scalable software architecture for distributed MMORPG traffic generation based on integration of UrBBaN-Gen and IMUNES

We present a scalable software architecture for distributed traffic generation capable of producing Massively Multiplayer Online Role-Playing Game (MMORPG) packet flows in a statistically accurate manner for thousands of concurrent players. The main challenge, to achieve truly massive scale traffic generation, has been achieved by introducing kernel based virtualization, pioneered by the network simulator/emulator IMUNES, into the User Behaviour Based Network Traffic Generation (UrBBan-Gen, introduced in our earlier work). The UrBBan-Gen software architecture consists of four modules: Service repository, Control function and user interface, Behaviour process, and Traffic generation process. IMUNES has been integratedinto the virtualization part of the Traffic generation process,which has resulted in two improvements: 1) increasing thenumber of generated packet flows while accurately replicating the required statistical properties, and, 2) introducing the ability to run various network scenarios in simulated, as well as real networks, under realistic traffic loads. With respect to the traffic generation capabilities of the previous version of UrBBan-Gen, which was based on Linux containers, the IMUNES based solution demonstrates higher scalability, lower packet loss rates, and lower CPU load for both the UDP traffic at high packet rate and “thin” TCP traffic flows typical for MMORPGs.