A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> Video communication over lossy packet networks such as the Internet is hampered by limited bandwidth and packet loss. This paper presents a system for providing reliable video communication over these networks, where the system is composed of two subsystems: (1) multiple state video encoder/decoder and (2) a path diversity transmission system. Multiple state video coding combats the problem of error propagation at the decoder by coding the video into multiple independently decodable streams, each with its own prediction process and state. If one stream is lost the other streams can still be decoded to produce usable video, and furthermore, the correctly received streams provide bidirectional (previous and future) information that enables improved state recovery for the corrupted stream. This video coder is a form of multiple description coding (MDC), and its novelty lies in its use of information from the multiple streams to perform state recovery at the decoder. The path diversity transmission system explicitly sends different subsets of packets over different paths, as opposed to the default scenarios where the packets proceed along a single path, thereby enabling the end- to-end video application to effectively see an average path behavior. We refer to this as path diversity. Generally, seeing this average path behavior provides better performance than seeing the behavior of any individual random path. For example, the probability that all of the multiple paths are simultaneously congested is much less than the probability that a single path is congested. The resulting path diversity provides the multiple state video decoder with an appropriate virtual channel to assist in recovering from lost packets, and can also simplify system design, e.g. FEC design. We propose two architectures for achieving path diversity, and examine the effectiveness of path diversity in communicating video over a lossy packet network. <s> BIB001 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> Real-time multimedia transport has stringent quality of service requirements, which are generally not supported by current network architectures. In emerging mobile ad hoc networks, frequent topology changes and link failures cause severe packet losses, which degrade the quality of received media. However, in such mesh networks, there usually exist multiple paths between any source and destination nodes. Such path diversity has been demonstrated to be effective in combating congestion and link failures for improved media quality. In this paper, we present a new protocol to facilitate multipath transport of real-time multimedia data. The proposed protocol, the multiflow real-time transport protocol (MRTP), provides a convenient vehicle for real-time applications to partition and transmit data using multiple flows. We demonstrate through analysis that data partitioning, which is an essential function of MRTP, can effectively reduce the short-range dependence of multimedia data, thus improving its queueing performance in underlying networks. Furthermore, we show that a few flows are sufficient for MRTP to exploit most of the benefits of multipath transport. Finally, we present a comprehensive simulation study on the performance of MRTP under a mobile ad hoc network. We show that with one additional path, MRTP outperformed single-flow RTP by a significant margin. <s> BIB002 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> Video-over-IP applications have recently attracted a large number of users on the Internet. Traditional client-server based video streaming solutions incur expensive bandwidth provision cost on the server. Peer-to-Peer (P2P) networking is a new paradigm to build distributed network applications. Recently, several P2P streaming systems have been deployed to provide live and on-demand video streaming services on the Internet at low server cost. In this paper, we provide a survey on the existing P2P solutions for live and on-demand video streaming. Representative P2P streaming systems, including tree, multi-tree and mesh based systems are introduced. We describe the challenges and solutions of providing live and on-demand video streaming in P2P environment. Open research issues on P2P video streaming are also discussed. <s> BIB003 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> In this paper, we propose a novel transport protocol that effectively utilizes available bandwidth and diversity gains provided by heterogeneous, highly lossy paths. Our Multi-Path LOss-Tolerant (MPLOT) protocol can be used to provide significant gains in the goodput of wireless mesh networks, subject to bursty, correlated losses with average loss-rates as high as 50%, and random outage events. MPLOT makes intelligent use of erasure codes to guard against packets losses, and a Hybrid-ARQ/FEC scheme to reduce packet recovery latency, where the redundancy is adaptively provisioned into both proactive and reactive FECs. MPLOT uses dynamic packet mapping based on current path characteristics, and does not require packets to be delivered in sequence to ensure reliability. We present a theoretical analysis of the different design choices of MPLOT and show that MPLOT makes an optimal trade-off between goodput and delay constraints. We test MPLOT, through simulations, under a variety of test scenarios and show that it effectively exploits path diversity in addition to aggregating path bandwidths. We also show that MPLOT is fair to single-path protocols like TCP-SACK. <s> BIB004 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> Cloud Gaming is a new kind of service, which combines the successful concepts of Cloud Computing and Online Gaming. It provides the entire game experience to the users remotely from a data center. The player is no longer dependent on a specific type or quality of gaming hardware, but is able to use common devices. The end device only needs a broadband internet connection and the ability to display High Definition (HD) video. While this may reduce hardware costs for users and increase the revenue for developers by leaving out the retail chain, it also raises new challenges for service quality in terms of bandwidth and latency for the underlying network. In this paper we present the results of a subjective user study we conducted into the user-perceived quality of experience (QoE)in Cloud Gaming. We design a measurement environment, that emulates this new type of service, define tests for users to assess the QoE, derive Key Influence Factors (KFI) and influences of content and perception from our results. <s> BIB005 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> Live video streaming applications have gained great popularity among users but exert great pressure on video servers and the Internet. Peer-to-Peer (P2P) networks provide an attractive solution due to their low cost and high scalability. A large number of P2P live video streaming schemes have been proposed and many deployments have appeared on the Internet. These schemes pursue vastly diverse directions, from mimicking IP multicast to BitTorrent-like swarming to distributed hash tables. In this paper, we provide a comprehensive and in-depth survey of P2P live video streaming schemes from an algorithmic perspective. Our purpose is to acquaint future designers with the critical design choices and their impacts on system performance. The primary objective of a P2P live video streaming system is to distribute packets from the video source to peers, and the collective paths through which a packet traverses form a tree. We focus on three aspects of how these trees are formed: determining the supplier-receiver relationships for each packet, handling the departure of the supplier or receiver before their relationship expires, and handling lost packets. We identify critical design choices in each aspect and propose a taxonomy according to these choices. Because the surveyed papers use different performance metrics and the reported results are heavily influenced by their experimental settings, we consider two measures to identify the impact of each design choice: we use a set of "internal" metrics in addition to the commonly used "external" metrics, and we examine performance metrics of schemes that have made the same design choice. For better understanding of how the design choices interact with one another and exposing future designers to the design choices specific to each individual scheme, we also provide systematic summaries for a large number of schemes. <s> BIB006 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> As voice, multimedia, and data services are converging to IP, there is a need for a new networking architecture to support future innovations and applications. Users are consuming Internet services from multiple devices that have multiple network interfaces such as Wi-Fi, LTE, Bluetooth, and possibly wired LAN. Such diverse network connectivity can be used to increase both reliability and performance by running applications over multiple links, sequentially for seamless user experience, or in parallel for bandwidth and performance enhancements. The existing networking stack, however, offers almost no support for intelligently exploiting such network, device, and location diversity. In this work, we survey recently proposed protocols and architectures that enable heterogeneous networking support. Upon evaluation, we abstract common design patterns and propose a unified networking architecture that makes better use of a heterogeneous dynamic environment, both in terms of networks and devices. The architecture enables mobile nodes to make intelligent decisions about how and when to use each or a combination of networks, based on access policies. With this new architecture, we envision a shift from current applications, which support a single network, location, and device at a time to applications that can support multiple networks, multiple locations, and multiple devices. <s> BIB007 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> The widespread deployment of various networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed, or multi-interface enabled devices. These trends drove researchers to investigate a wide spectrum of solutions, at different layers of the protocol stack, that utilize available interfaces in such devices by aggregating their bandwidth. In this survey paper, we provide an overview and examine the evolution of bandwidth aggregation solutions over time. We begin by describing the bandwidth aggregation problem. We then investigate the common features of proposed bandwidth aggregation systems and break them down into two major categories: layer-dependent and layer-independent features. Afterwards, we discuss the evolution trends in the literature and share some open challenges requiring further research. We end the survey with a brief presentation of related work in tangential research areas. <s> BIB008 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> Multipath routing is an efficient technique to route data in wireless sensor networks (WSNs) because it can provide reliability, security and load balance, which are especially critical in the resource constrained system such as WSNs. In this paper we provide a survey of the state-of-the-art of proposed multipath routing protocols for WSNs, which are classified into three categories, infrastructure based, non-infrastructure based and coding based, based on the special techniques used in building multiple paths and delivering sensing data. For each category, we study the design of protocols, analyze the tradeoff of each design, and overview several representing protocols. In addition, we give a summery of design goals, challenges, and evaluation metrics for multipath routing protocols in resource constrained systems in general. <s> BIB009 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> The Internet infrastructure often supports multiple routes between two communicating hosts and, today, especially mobile hosts usually offer multiple network interfaces, so that disjoint paths between the hosts can be constructed. Having a number of (partly or fully) disjoint paths available may allow applications to distribute their traffic, aggregate capacity of different paths, choose the most suitable subset of paths, and support failover if a path fails. Exploiting multipath characteristics has been explored for TCP, but the requirements for real-time traffic differs notably. In this paper, we devise a multipath communication model for Real-time Transport Protocol (RTP); present minimal set of required protocol extensions; develop algorithms for scheduling RTP traffic across multiple paths at the sender and a corresponding de-jittering algorithm at the receiver side; and evaluate our proposal in varying scenarios using media traffic across different emulated mobile access network setups. <s> BIB010 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> Video streaming is gaining popularity among mobile users. The latest mobile devices, such as smart phones and tablets, are equipped with multiple wireless network interfaces. How to efficiently and cost-effectively utilize multiple links to improve video streaming quality needs investigation. In order to maintain high video streaming quality while reducing the wireless service cost, in this paper, the optimal video streaming process with multiple links is formulated as a Markov Decision Process (MDP). The reward function is designed to consider the quality of service (QoS) requirements for video traffic, such as the startup latency, playback fluency, average playback quality, playback smoothness and wireless service cost. To solve the MDP in real time, we propose an adaptive, best-action search algorithm to obtain a sub-optimal solution. To evaluate the performance of the proposed adaptation algorithm, we implemented a testbed using the Android mobile phone and the Scalable Video Coding (SVC) codec. Experiment results demonstrate the feasibility and effectiveness of the proposed adaptation algorithm for mobile video streaming applications, which outperforms the existing state-of-the-art adaptation algorithms. <s> BIB011 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work. <s> BIB012 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> Utilizing the dormant path diversity through multipath routing in the Internet to reach end users—thereby fulfilling their QoS requirements—is rather logical. While offering better resource utilization, better reliability, and often even much better quality of experience (QoE), multipath routing and provisioning was shown to help network and data center operators achieve traffic engineering in the form of load balancing. In this survey, we first highlight the benefits and basic Internet multipath routing components. We take a top-down approach and review various multipath protocols, from application to link and physical layers, operating at different parts of the Internet. We also describe the mathematical foundations of the multipath operation, as well as highlight the issues and challenges pertaining to reliable data delivery, buffering, and security in deploying multipath provisioning in the Internet. We compare the benefits and drawbacks of these protocols operating at different Internet layers and discuss open issues and challenges. <s> BIB013 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> IP networks were designed to provide general connectivity. At their advent, routing methods focused only on finding one optimal path between given endpoints. Although many solutions to sending traffic via multiple paths have appeared over time, the majority of current IP networks are still managed to support only single-path transmissions. This survey examines various approaches which can provide multipath transmissions in existing IP networks. Firstly, the most recognizable solutions are presented, and later, less well-known proposals are introduced. We show how it is possible to realize multipath transmission in source and hop-by-hop routing, multi-topology routing, bio-inspired routing solutions, Valiant's routing, Multi-Protocol Label Switching, Software-Defined Networks, Flow-Aware Multi-Topology Adaptive Routing, Shortest-Path Bridging, Transparent Interconnection of Lots of Links, network virtualization, and Multipath TCP. Moreover, the mentioned approaches are compared, contrasted and subjectively assessed. The goal of the survey is to show that multipath transmissions can be achieved in the current IP networks and in many different ways. <s> BIB014 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> 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. <s> BIB015 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> HTTP adaptive streaming (HAS) is the most recent attempt regarding video quality adaptation. It enables cheap and easy to implement streaming technology without the need for a dedicated infrastructure. By using a combination of TCP and HTTP it has the advantage of reusing all the existing technologies designed for ordinary web. Equally important is that HAS traffic passes through firewalls and works well when NAT is deployed. The rate adaptation controller of HAS, commonly called adaptive bitrate selection (ABR), is currently receiving a lot of attention from both industry and academia. However, most of the research efforts concentrate on a specific aspect or a particular methodology without considering the overall context. This paper presents a comprehensive survey of the most significant research activities in the area of client-side HTTP-based adaptive video streaming. It starts by decomposing the ABR module into three subcomponents, namely: resource estimation function, chunk request scheduling, and adaptation module. Each subcomponent encapsulates a particular function that is vital to the operation of an ABR scheme. A review of each of the subcomponents and how they interact with each other is presented. Furthermore, those external factors that are known to have a direct impact on the performance of an ABR module, such as content nature, CDN, and context, are discussed. In conclusion, this paper provides an extensive reference for further research in the field. <s> BIB016 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> The vision of wireless multimedia sensor networks (WMSNs) is to provide real-time multimedia applications using wireless sensors deployed for long-term usage. Quality of service assurances for both best effort data and real-time multimedia applications introduced new challenges in prioritizing multipath routing protocols in WMSNs. Multipath routing approaches with multiple constraints have received considerable research interest. In this paper, a comprehensive survey of both best effort data and real-time multipath routing protocols for WMSNs is presented. Results of a preliminary investigation into design issues affecting the development of strategic multipath routing protocols that support multimedia data in WMSNs are also presented and discussed from the network application perspective. <s> BIB017 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> In this paper, we present a novel QoE-aware SDN/NFV system by utilizing and integrating Multi-path TCP (MPTCP) and Segment Routing (SR) paradigms. We propose a QoE-based Multipath Source Routing (QoEMuSoRo) algorithm that achieve an optimized end-to-end QoE for the end-user by forwarding MPTCP subflows using SR over SDN/NFV. We implement and validate the proposed scheme through DASH experiments using Mininet and POX controller. To demonstrate the effectiveness of our proposal, we compare the performance of our QoE-aware MPTCP SDN/NFV SR-based proposal, the MPTCP and regular TCP in terms of system throughput and the end-user's QoE. Preliminary results shows that, our approach outperforms the other aforementioned methods. <s> BIB018 </s> A Holistic Survey of Wireless Multipath Video Streaming <s> I. INTRODUCTION <s> The increasing popularity of live video streaming from mobile devices, such as Facebook Live, Instagram Stories, Snapchat, etc. pressurizes the network operators to increase the capacity of their networks. However, a simple increase in system capacity will not be enough without considering the provisioning of quality of experience (QoE) as the basis for network control, customer loyalty, and retention rate and thus increase in network operators revenue. As QoE is gaining strong momentum especially with increasing users’ quality expectations, the focus is now on proposing innovative solutions to enable QoE when delivering video content over heterogeneous wireless networks. In this context, this paper presents an overview of multimedia delivery solutions, identifies the problems and provides a comprehensive classification of related state-of-the-art approaches following three key directions: 1) adaptation; 2) energy efficiency; and 3) multipath content delivery. Discussions, challenges, and open issues on the seamless multimedia provisioning faced by the current and next generation of wireless networks are also provided. <s> BIB019
M ULTIMEDIA services (e.g., Skype, FaceTime) and ondemand mobile video content (e.g., Hulu, YouTube, Netflix) have become part of daily use. Likewise, online cloud gaming is a very popular entertainment BIB005 . Such applications require high quality video streaming capabilities to meet the end user expectations. The annual Cisco reports [11] ,  show that, since 2012, mobile video has represented more than half of global mobile data traffic and will keep being responsible for the largest traffic growth upfront. The increase of on-demand video is expected to affect mobile networks as much as it will affect fixed networks. Another trend is that Ultra HD (UHD)/4K video will be more prevalent in the network, as well as Multi-View Video (MVV) and even 8K, in the short-mid term. For example, current smartphones are already able to record 4K videos at a bit rate of around 42-48 Mbps  ,  ,  , [16] . Delivering high-quality video streaming services makes the task of providing real-time wireless transmission of multimedia while ensuring Quality of Experience (QoE) quite challenging due to bandwidth and time constrains BIB016 . One of the approaches to tackle this challenging scenario is to add multipath transmission where video streaming can be delivered over IP broadcast and/or broadband with bidirectional connectivity between video sources and users. Table I presents published results on the potential performance gains wireless video streaming when exploiting multiple network paths. Several surveys in the literature have covered different aspects of multipath data communications in general, such as BIB012 , BIB013 , BIB015 , BIB014 , BIB007 , BIB008 . However, to the best of our knowledge, this is the first survey focusing especially on the multipath transmission of wireless video. The contributions of this survey include new insights, protocol technique discussions, and a taxonomy of existing solutions, altogether serving as a valuable source of information to researchers and developers in this field. More specifically, we focus on the data plane problem of how to schedule data on multiple paths and intentionally leave out works on multipath routing, i.e. the control plane aspects of how to compute routes such as multipath proposals BIB018 ,  based Software-Defined Networking (SDN)  . Readers interested in those aspects are referred to recent surveys BIB012 , BIB013 covering control plane approaches. We also leave out of scope wireless sensor networks and refer to surveys on multipath video streaming in this type of networks BIB017 , BIB009 . Peer-to-peer (P2P) video streaming applications, which have been surveyed in-depth BIB006 , BIB003 , are also not in the scope of this survey. In the following, we provide a brief overview of the most related and recently published surveys on multipath data communications BIB012 , BIB013 , BIB015 , BIB019 , summarized in Table II. Qadir et al. BIB012 investigated multipathing for data in general, mainly on the network layer. Besides that, they also investigated multipath transmission on the transport layer. Their investigation is organized by discussing key aspects of network-layer multipathing: 1) route computation (source routing, hop-by-hop routing, overlay routing, and SDN-based routing), 2) routing metrics (e.g., delay, bandwidth) 3) load balancing techniques (static or dynamic) 4) number of paths to use 5) how to use multiple paths together. Singh et al. BIB013 cover multipathing for data communications in general, covering fundamentals of multipath routing, multipath computation algorithms, multipath forwarding algorithms, and traffic splitting algorithms. The work also reviews various multipath protocols following a layer-based structure, from the application layer to the physical layer. Li et al. BIB015 investigates multipath solutions for data in general and presents research problems at various protocol layers including cross layer approaches. Although some video streaming multipath solutions are discussed in this survey, many of the video streaming specific issues are not considered (e.g., importance and influence of video content). In addition, the work does not cover multipath attempts on key video streaming protocols, e.g., Dynamic Adaptive Streaming over Performance improvements compared to single path MRTP BIB002 Mesh ad hoc network with high burst loss RTP PSNR gains of 1.26 dB more in multipath than single path, 64.14% loss rate reduction together with making packet losses more random. MPRTP BIB010 Two 3G links with bandwidth variations RTP In the quick bandwidth scenario, PSNR is better than the single path with 0.5% and 1.0% loss rate. In the slow bandwidth change scenario, it is comparable to the single path with 1.0% loss rate. RTRA BIB011 WiFi and Bluetooth networks with bandwidth variations DASH RTRA shows better results for both slow and rapid changing bandwidth scenarios in terms of startup delay (reduced up to half), playback fluency average (no segment missing in multipath but high misses in some single path scenarios), playback quality (PSNR improved 1 to 3 dB), quality switch (up to 4 times reduction), and bandwidth utilization. MPLOT BIB004 Wireless mesh network with burst loss rate of 50% TCP MPLOT archives 75%, with a mean of 50%, more bandwidth aggregation compared to the single path. Apostolopoulos et al. BIB001 Burst lossy wireless network IP source routing/relay While the proposed approach results in drops of only 1.5 to 7 dB, but single path drops of 12 to 15 dB. 