Channel bonding (CB) is a proven technique to increase bandwidth and reduce delays in wireless networks. It has been applied in traditional wireless networks such as cellular networks and wireless local area networks along with the emerging cognitive radio networks. This paper first focuses on providing a survey of CB schemes for traditional wireless networks such as cellular networks, wireless local area networks, and wireless sensor networks, and then provides a detailed discussion on the CB schemes proposed for cognitive radio networks. Finally, we highlight a number of issues and challenges regarding CB in cognitive radio sensor networks and also provide some guidelines on using CB schemes in these futuristic networks.

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A Survey of Channel Bonding for Wireless Networks and Guidelines of Channel Bonding for Futuristic Cognitive Radio Sensor Networks

Smart devices equipped with multiple network interfaces are becoming commonplace. Nevertheless, even though multiple interfaces can be used to connect to the Internet, their capabilities have not been fully utilized yet because the default TCP/IP stack supports only a single interface for communication. This situation is now changing due to the emergence of multipath protocols on different network stack layers. For example, many IP level approaches have been proposed utilizing tunneling mechanisms for hiding multipath transmission from the transport protocols. Several working groups under IEEE and IETF are actively standardizing multipath transmission on the link layer and transport layer. Application level approaches enable multipath transmission capability by establishing multiple transport connections and distributing data over them. Given all these efforts, it is beneficial and timely to summarize the state-of-the-art, compare their pros and cons, and discuss about the future directions. To that end, we present a survey on multipath transmission and make several major contributions: 1) we present a complete taxonomy pertaining to multipath transmission, including link, network, transport, application, and cross layers; 2) we survey the state-of-the-art for each layer, investigate the problems that each layer aims to address, and make comprehensive assessment of the solutions; and 3) based on the comparison, we identify open issues and pinpoint future directions for multipath transmission research.

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Multipath Transmission for the Internet: A Survey

Application optimization in mobile cloud computing

Visible light communication (VLC) has wide unlicensed bandwidth, enables communication in radiofrequency-sensitive environments, realizes energy-efficient data transmission, and has the potential to boost the capacity ofwireless access networks through spatial reuse. On the other hand, WiFi provides more coverage than VLC and does not suffer from the likelihood of blockage due to the line-of-sight requirement of VLC. In order to take the advantages of both WiFi and VLC, we propose and implement two heterogeneous systems with Internet access. One is the hybrid WiFi–VLC system, utilizing a unidirectional VLC channel as the downlink and reserving the WiFi backchannel as the uplink. The asymmetric solution resolves the optical uplink challenges and benefits from the full-duplex communication based on VLC. To further enhance the robustness and increase throughput, the other system is presented, in which we aggregate WiFi and VLC in parallel by leveraging the bonding technique in the Linux operating system. We also theoretically prove the superiority of the aggregated system in terms of average system delay. Online experiment results reveal that the hybrid system outperforms the conventional WiFi for crowded environments in terms of throughput and Web page loading time, and also demonstrate the further improved performance of the aggregated system when considering the blocking duration and the distance between the access point and the user device.

Design and analysis of a visible-light-communication enhanced WiFi system

The spectrum limitation of single wireless networks prompts the bandwidth aggregation of heterogeneous access medium (e.g., LTE and Wi-Fi) to support high-quality real-time video services. Energy consumption of mobile devices is of vital significance to provide user-satisfied multimedia streaming applications. However, it is challenging to develop an energy-efficient bandwidth aggregation scheme with regard to the stringent delay and quality constraints imposed by wireless video transmission. To address the critical problem, this paper presents an Energy-quaLity aware Bandwidth Aggregation (ELBA) scheme. First, we develop an analytical framework to model the delay-constrained energy-quality tradeoff for multipath video transmission over heterogeneous wireless networks. Second, we propose a bandwidth aggregation framework that integrates energy-minimized rate adaptation, delay-constrained unequal protection, and quality-aware packet distribution. The proposed ELBA scheme is able to effectively leverage the wireless channel diversity and video frame priority for enabling energy-minimized quality-guaranteed streaming to multihomed devices within imposed deadline. We conduct the performance evaluation through both experiments over real wireless networks and extensive emulations in Exata platform. Experimental results demonstrate the performance advantages of ELBA over existing bandwidth aggregation schemes in energy conservation, video quality, and end-to-end delay.

Energy-Efficient Bandwidth Aggregation for Delay-Constrained Video Over Heterogeneous Wireless Networks

Review: Bandwidth aggregation in heterogeneous wireless networks: A survey of current approaches and issues

Most multipath video transmission schemes focus on minimizing video packets delivery time but do not consider protecting the video packets from loss. Packet loss can have undesirable effects on the video quality. This is especially true for frame-based video streams, such as Motion Pictures Group (MPEG) video, where the loss of a video frame can result in the loss of all the frames that depend on it for decoding. This propagation of loss to dependent frames can cause considerable video distortion, which, in turn, can lead to poor video presentation. This paper proposes a multipath MPEG video streaming solution that can prevent the loss of video frames while ensuring that the frames can be delivered to meet their playback deadlines. We show through trace-driven simulation that the proposed solution can achieve better results in terms of peak signal-to-noise ratio (PSNR), structural similarity index (SSIM) and visual quality.

MPEG video streaming solution for multihomed-terminals in heterogeneous wireless networks

Aggregating fractional bandwidth from multiple links in heterogeneous wireless networks can provide an opportunity for network providers to scale up capacity for multi-homed terminals. Multi-homed terminals come equipped with multiple interfaces, which can be used to transmit and receive data over multiple paths simultaneously. This can improve performance in terms of increased throughput, short delays, and loss resilience. However, parallel transmission over heterogeneous links can lead to problems, such as packet reordering. Packet reordering occurs when packets of the same stream arrive at the receiver out of the required order. Transmission Control Protocol (TCP) misinterprets packet reordering as congestion loss and reacts by shrinking the congestion window and launching spurious fast retransmit. Consequently, the application throughput can drop dramatically. Packet reordering can also induce additional delays, which can degrade performance of delay-sensitive applications. In this paper, we present a new multipath packet transmission solution that addresses packet reordering while ensuring that delay-sensitive packets are delivered to meet their deadlines. The proposed solution is evaluated in the ns-3 simulation environment. The simulation results reveal that our solution reduces packet reordering while improving throughput performance.

Using Multiple Links Simultaneously to Increase Capacity for Multi-homed Terminals in Heterogeneous Wireless Networks

Emerging user terminals come equipped with multiple network interfaces that can be configured to simultaneously support an application that requires more bandwidth resources than a single network can provide. The application can enjoy the support by striping data units across the different interfaces for parallel transmission to the receiver. However, this requires efficient multipath transmission mechanisms to assure improved performance. In this paper, we focus on parallel transmission of scalable video using multiple links in heterogeneous wireless networks. Recent research efforts on multipath scalable video streaming have focused on delay characteristics of the available wireless paths to optimize video playback. However, delay-based solutions risk significant loss of video packets, as the packets may be scheduled for transmission over low delay but lossy paths. Packet loss can lead to undesirable effects in scalable video, where the loss of a video packet can propagate to dependent packets, thus resulting in perceptible video artifacts. We propose a new multipath scalable video streaming model that considers not only delay but also loss characteristics to improve quality of the multipath streaming process. We show through trace-driven simulations that our solution outperforms other solutions in terms of video quality measured using peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM).

Allen L. Ramaboli

Papers

Review: Bandwidth aggregation in heterogeneous wireless networks: A survey of current approaches and issues

MPEG video streaming solution for multihomed-terminals in heterogeneous wireless networks

Using Multiple Links Simultaneously to Increase Capacity for Multi-homed Terminals in Heterogeneous Wireless Networks

Improving H.264 Scalable Video Delivery for Multi-homed Terminals Using Multiple Links in Heterogeneous Wireless Networks