Wireless IP Networks Research Articles

Study of performance of a ‘second‐generation wavelet video encoder with a scalable rate’

The purpose of data compression, in general, is to encode information using fewer bits than the original representation. In video coding, the goal is to reduce the bitrate of a video while preserving an acceptable quality for visual perception. In this study, the authors describe and study the performance of a proposed video coding framework that utilises a second-generation wavelet transform specifically Spline 5/3. This framework allows for unequal error protection and has a better performance than many well know video coding systems especially for low bitrate applications. The proposed framework allows for bit rate control according to users need both at the encoder end and the decoder end, which is great for networks with variable conditions like wireless IP networks since the noise can reduce the available bandwidth and the number of users can vary from time to time.

Performance evaluation and implementation of IP and robust header compression schemes for TCP and UDP traffic in static and dynamic wireless contexts

Modern cellular networks utilising the long?term evolution (LTE) set of standards face an ever?increasing demand for mobile data from connected devices. Header compression is commonly employed to minimise the overhead for IP?based cellular network traffic. In this paper, we evaluate the three header compression implementations used by these networks with respect to their potential throughput increase and complexity for different mobile service scenarios over wireless IP networks. Specifically, we consider header compression as defined by (i) IP Header Compression (RFC 2507), (ii) Robust Header Compression version 1 (RFC 3095), and (iii) the recently updated Robust Header Compression version 2 (RFC 5225) with TCP/IP profile (RFC 6846). The contribution of this article is the performance evaluation of IP Header Compression (IPHC) for UDP and TCP, as well as its evaluation in contrast to the Robust Header Compression (RoHC) methods in a comparative overview for real?world mobile scenarios. Our results show that all implementations have great potential for saving bandwidth in IP?based wireless networks, even under varying channel conditions. While both RoHC versions generally provide more reliable results than IPHC, we find that on a unidirectional channel IPHC could perform better. However, if a TCP connection is prone to packet reordering (e.g., by retransmissions), IPHC?s performance drops drastically, while RoHC?s does not exhibit any significant performance reduction.

무선 IP 네트워크에서 전용선 모뎀 사용가능성 검증

A leased line modem usability was evaluated and investigated in the wireless internet protocol(IP) network. The signal of the modem in the circuit switching network was translated to IP packet by using several voice codecs (PCM, G.711A, G.711μ, and etc.) and transmitted through the wireless IP network. The wireless IP network was simulated by the Tactical information and communication network Modeling and simulation Software(TMS). The performance and usability of the leased line modem are simulated using the system-in-the-loop(SITL) function of TMS with respect to packet delay, jitter, packet discard ratio, codecs, and wireless link BER.

Design on Energy-saving Mechanism of 6LoWPAN Wireless Sensor Network

Wireless sensor network LAN is mostly ad hoc form, and it only can access and process information in the ded- icated control center. IP network is widely used, if such a local wireless sensor network access can be accessed to internet backbone network, it will bring users more convenience. This paper designs a new wireless sensor network of 6LoWPAN using IPv6 and IEEE802.15.4 protocol, and adopts the low duty and multi distributed IP to optimize the network, finally saving cyber source and reducing the network energy consumption in the process of sending, receiving data, which achieves a seamless mosaic of wireless sensor network and IP network. This paper uses solar cell technology to improve the terminal sensor of sensor network and reduce the energy consumption of sensor and processor. Finally, based on the testing of wireless network, 6LoWPAN wireless networks has a significant energy consumption decrease in each function module and information transmission environment, which provides a theoretical reference for the study on wireless sensor network energy saving mechanism.

Mobile flow-aware networks for mobility and QoS support in the IP-based wireless networks

As the volume of mobile traffic consisting of video, voice, and data is rapidly expanding, a challenge remains with the mobile transport network, which must deliver data traffic to mobile devices without degrading the service quality. Since every Internet service holds its own service quality requirements, the flow-aware traffic management in fine granularity has been widely investigated to guarantee Quality of Service (QoS) in the IP networks. However, the mobile flow-aware management has not been sufficiently developed yet because of the inherent constraints of flow routing in the mobile networks regarding flow-aware mobility and QoS support. In this paper, we propose a flow-aware mobility and QoS support scheme called mobile flow-aware network (MFAN) for IP-based wireless mobile networks. The proposed scheme consists of dynamic handoff mechanisms based on QoS requirements per flow to reduce the processing overhead of the flow router while ensuring QoS guarantee to mobile flows. The performance analyses of the proposed scheme demonstrate that MFAN successfully supports the mobile flow traffic delivery while satisfying the QoS requirement of flows in the wireless mobile IP networks.

SPOT GNSS in Emergency and Location Based Services

Location Based Systems (LBS) market has emerged exponentially since early 2000 in the wake of growing need for Emergency Relief Applications. The argument of course outstanding is which device outperforms all other in diverse scenarios without failure. While many purpose built LBS are in use, SPOT satellite messenger gained attention for its reliability. This paper summates the system architecture and experimental tests results with those of competing Assisted and Global Navigation Satellite Systems (A/GNSS). Our test bed comprised of 26 test points with pre-established database of GNSS difficulty levels in diverse environments in UNSW. Parameters of interest are availability, accuracy and Time to First Fix (TTFF). Relative benchmarking proves SPOT’s higher TTFF and higher failure rate in general. While High Sensitivity GNSS and Assisted GNSS (MSBased and MS-Assisted) had higher availability, higher accuracy and lower TTFF. Altogether fewer failure scenarios, trustworthy coverage with cost effectiveness were observed for MS-Based AGNSS which is vital for LBS applications. However reliance on wired or wireless IP network potentially limits the performance in nonexistent underlying infrastructure in remote applications. SPOT demonstrated higher TTFF and failure rates in test scenario. On the contrary Assisted GNSS (MS-Based or MS-Assisted) can provide a reliable, cost effective and open source alternative to SPOT satellite messenger with better TTFF, availability and accuracy for consumer and research applications.

Real-time delay statistics in wireless IP networks

Abstract. In the wireless communication, the variation of the transmission delay is called jitter and is one of the variables responsible for the degradation of the service quality. Jitter is present in every section of the transmission system. Its stochastic behavior depends on the technology implemented in the system and the service provided by the system. This paper focuses on mathematical modeling and phenomenological analysis of the jitter encountered by the real-time services in a wireless network. Using the data made available to the public by the wireless industry, we explore the stochastic characterizations of the jitter in a wireless IP networks. Within the scope of real-time service, we studied the relation between delay, jitter and the inter-packet time. Evaluation of the sample data indicates a long range dependence of the inter-packet time of the received packets in a real-time connection. The result helps understanding the transmission delay encountered by the real-time service over wireless IP networks.

Adaptive Rate Optimal Design for Wireless Heterogeneous Networks: Jointly Congestion Discrimination and Queue Updating

In this paper, we propose a novel rate adaptive optimization scheme for streaming media transmission over wireless heterogeneous IP networks. In the proposed adaptive scheme, through the analysis of the packet loss characteristics in wireless channel, we develop the relationship between the packet loss rates and the packet sizes. Furthermore, the scheme detects the nature of packet losses by sending large and small packets alternately, and then adopts an adaptive rate optimization strategy to decrease the network congestion and increase the network throughput. Using congestion discrimination and updating factor, the scheme can adapt to the changes of network states quickly and improve delivery quality of wireless multimedia streaming. Simulation results show that, in comparisons to the existing rate optimization algorithms, our proposed scheme offers significantly improved performance in terms of throughput and network congestion, especially when the channel quality is poor in different network topology environments.

Anonymous Authentication Scheme for Wireless IP Networks under Trusted Computing

Anonymous Authentication Scheme for Wireless IP Networks under Trusted Computing

Video Streaming Performance Under Well-Known Packet Scheduling Algorithms

Video streaming is becoming increasingly popular among the wireless users. However, supporting video streaming over the wireless networks is not an easy task due to the dynamic radio propagation environment, limited radio resources as well as Quality of Service (QoS) requirements of the video streaming that need to be satisfied at acceptable levels. Most studies proposed to support video streaming are computationally expensive to be used in Orthogonal Frequency Division Multiple Access (OFDMA) based wireless IP networks. This paper evaluates video streaming performance under three well-known algorithms that are more practical to be used in the OFDMA based wireless IP networks due to their reduced complexity. It is demonstrated via computer simulation that Proportional Fair (PF) algorithm outperforms other well-known algorithms by providing video streaming QoS at acceptable levels whilst maximizing cell throughput.

Adaptive FEC algorithm based on prediction of video quality and bandwidth utilization ratio

In this paper, a channel adaptive FEC algorithm is proposed which balances the trade-off between the QoS of video transmission and the bandwidth utilization ratio in wireless IP networks. Our algorithm can dynamically adjust to a suboptimal number of FEC redundant packets to cater to the time-varying wireless channel. For the sake of obtaining the suboptimal amount of FEC redundant packets, we derive two analytical models, one is the playable frame rate in MPEG video stream, another is the effective utilization ratio of FEC. Based on these analytical models, a suboptimal value of redundant packets, which makes both the quality of video stream and the effective utilization ratio of FEC approximate their maximum, is calculated by predicting the quality of video stream and effective utilization ratio of FEC under different network conditions (characterized by packet loss probability in this paper). The simulation results indicate that the QoS of wireless video transmission and the bandwidth utilization ratio are improved by employing the proposed algorithm.

Minimization of Handoff Failure Probability for Next-Generation Wireless Systems

During the past few years, advances in mobile communication theory have enabled the development and deployment of different wireless technologies, complementary to each other. Hence, their integration can realize a unified wireless system that has the best features of the individual networks. Next-Generation Wireless Systems (NGWS) integrate different wireless systems, each of which is optimized for some specific services and coverage area to provide ubiquitous communications to the mobile users. In this paper, we propose to enhance the handoff performance of mobile IP in wireless IP networks by reducing the false handoff probability in the NGWS handoff management protocol. Based on the information of false handoff probability, we analyze its effect on mobile speed and handoff signaling delay.

Dynamic QoS Evaluation of Multimedia Contents in Wireless Networks by “Double-Boomerang” Watermarking

This work presents a cooperative network-aware processing of multimedia content for dynamic quality of service management in wireless IP networks. Our technique can be also used for quality control in UMTS environments, exploiting the tracing watermarking recently introduced in literature. In this work, we use the transmitted video-sequences to monitor the QoS in a videoconference call. The video-sequence of every active user travels on the communication link, one time as video (transparent mode), one time as watermark (hidden mode) describing a boomerang trajectory. The results obtained through our simulation trials confirm the validity of such approach. In fact, the advantages of distributing the management process are (i) an easier and more precise localization of the cause of QoS problems, (ii) a better knowledge of local situations, (iii) a lower complexity for a single QoS agent and (iv) an increase in possible actions.

Performance analysis of movements detection with RA beaconing in wireless IP networks

In networks supporting Mobile IP (MIP), the address configuration of a Mobile Node (MN) is an important part of the handoff process, which is based on the detection of movement between different subnetworks. The movement detection in wireless IP network is usually performed by means of Router Advertisement (RA) messages which are sent with a fixed and constant period. The higher is the rate of these messages, the lower the handoff delay is and the higher is the bandwidth occupation on the wireless medium. To trade off these values, we propose a method to decrease the bandwidth occupation of movement detection messages while confining part of the L3 handoff setup latency under acceptable values, for instance 15 ms ÷ 40 ms. The benefit on the bandwidth occupation with respect to the constant rate technique is between 25% ÷ 40%, depending on the interval of advertisement messages. Our technique is based on the windowing of the RA messages trains, each window being placed at the predicted time instants of handoff arrivals.

Scalable inter-area handovers for hierarchical wireless networks

The aim of future IP-based wireless communications is to provide mobile users access to the desired service with the appropriate quality at any place. Besides mobility support and QoS provision, the increase of wireless heterogeneous access is equally significant for fulfilling such a vision. This increase of wireless access is associated with expanding the core IP network infrastructure, raising scalability concerns, especially when a large amount of routers are managed as a single domain. Configuring hierarchy is an essential element to scale large wireless IP networks where the impact of mobility is not yet fully explored. This article first identifies the key elements for the provision of an efficient hierarchical wireless architecture and second proposes an inter-area handover policy that improves network scalability. A simulation-based study demonstrates the contribution of the proposed approach to the reduction of mobility and routing signaling as well as MH blocking and dropping rates.

모바일 IP 스토리지 상에서 멀티미디어 컨텐츠 실행을 위한 효율적인 무선랜 장치 전력제어 기법

ABSTRACT Mobile IP storage has been proposed to overcome storage limitation in the flash memory and hard disks. It provides almost capacity-free space for mobile devices over wireless IP networks. However, battery lifetime of the mobile devices is reduced rapidly because of power consumption with continuous use of a WLAN device when multimedia contents are being streamed through the mobile IP storage. This paper proposes an energy-efficient WLAN device power control technique for streaming multimedia contents with the mobile IP storage. The proposed technique consists of a prefetch buffer input/output module, a WLAN device power control module, and a reconfigurable prefetch buffer module. Besides, it adaptively determines the size of the prefetch buffer according to a quality of the multimedia contents, and it dynamically controls the power mode of the WLAN device on the basis of power on-off operations while streaming the multimedia contents. We evaluate the performance of the proposed technique on a PXA270-based mobile device that employs the embedded linux 2.6.11, Intel iSCSI reference codes, and a WLAN device. Extensive experiments reveal that the proposed technique can save the energy consumption of the WLAN device up to 8.5 times with QVGA multimedia contents, as compared with no power control.Keywords:Wireless LAN, Power Control, Mobile IP Storage

Modeling and Simulation of Self-Similar Traffic in Wireless IP Networks

The article examines self-similar properties of real telecommunications network traffic data over a wide range of time scales. These self-similar properties are very different from the properties of traditional models based on Poisson and Markov-modulated Poisson processes. Simulation with stochastic and long range dependent traffic source models is performed, and the algorithms for buffer overflow simulation for finite buffer single server model under self-similar traffic load SSM/M/1/B are explained. The algorithms for modeling fixedlength sequence generators that are used to simulate self-similar behavior of wireless IP network traffic are developed and applied. Numerical examples are provided, and simulation results are analyzed.

A Multilanguage Study of the Quality of Interleaved MELP Voice Traffic Over a Lossy Network

The quality of time sensitive interactive voice traffic can seriously degrade if moved over lossy wired or wireless IP networks, particularly with low rate speech. One technique that can be used to improve the quality is to transmit interleaved, and possibly duplicated, voice frames. This paper compares the quality of non-interleaved clear MELP voice traffic with the quality of several interleaving schemes over a high loss packet network. Multiple NATO languages were tested. The results show that interleaving can significantly improve the perceived voice quality, but at the expense of an increase in mouth-to-ear delivery delay and, if redundancy is enabled, an increase in required bandwidth. The improved voice quality can be quite significant at high packet loss rates.

A Bayesian Business Model for Video-Call Billing for End-to-End QoS Provision

Wireless communications and IP networks will evolve into a new converged vision, which is called ldquobeyond the third generation,rdquo where charging and billing will be essential tools for customer care to fight competition and to assure operator's revenue. This contribution proposes a business model for video-call billing founded on Bayes' decision testing. It is based on the end-to-end quality of service (QoS) estimated by exploiting the tracing watermarking procedure, which has recently been introduced into the literature. In particular, we employ the watermark embedded in each transmitted video sequence to monitor the QoS of the communication link and adequately charge the calling user, depending on the received video quality. Adopting such a Bayesian business model, we translate the network operator's paradigm of ldquo <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pay</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">as</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">you</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">talk</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(and</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">watch)</i> rdquo to ldquo <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pay</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">how</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">you</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">talk</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(and</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">watch)</i> ,rdquo maximizing the operator's profit under a constrained video quality for end users. Wide simulation trials are conducted to characterize the effectiveness of the proposed method, using different business scenarios, confirming the validity of such an approach.

Native support of idle mode in wireless IP networks

Native support of idle mode in wireless IP networks