46 research outputs found
Random Linear Network Coding for 5G Mobile Video Delivery
An exponential increase in mobile video delivery will continue with the
demand for higher resolution, multi-view and large-scale multicast video
services. Novel fifth generation (5G) 3GPP New Radio (NR) standard will bring a
number of new opportunities for optimizing video delivery across both 5G core
and radio access networks. One of the promising approaches for video quality
adaptation, throughput enhancement and erasure protection is the use of
packet-level random linear network coding (RLNC). In this review paper, we
discuss the integration of RLNC into the 5G NR standard, building upon the
ideas and opportunities identified in 4G LTE. We explicitly identify and
discuss in detail novel 5G NR features that provide support for RLNC-based
video delivery in 5G, thus pointing out to the promising avenues for future
research.Comment: Invited paper for Special Issue "Network and Rateless Coding for
Video Streaming" - MDPI Informatio
Random Linear Fountain Code with Improved Decoding Success Probability
In this paper we study the problem of increasing the decoding success
probability of random linear fountain code over GF(2) for small packet lengths
used in delay-intolerant applications such as multimedia streaming. Such code
over GF(2) are attractive as they have lower decoding complexity than codes
over larger field size, but suffer from high transmission redundancy. In our
proposed coding scheme we construct a codeword which is not a linear
combination of any codewords previously transmitted to mitigate such
transmission redundancy. We then note the observation that the probability of
receiving a linearly dependent codeword is highest when the receiver has
received k-1 linearly independent codewords. We propose using the BlockACK
frame so that the codeword received after k-1 linearly independent codeword is
always linearly independent, this reduces the expected redundancy by a factor
of three.Comment: This paper appears in: Communications (APCC), 2016 22nd Asia-Pacific
Conference o
Digital Twin-Based Network Management for Better QoE in Multicast Short Video Streaming
Multicast short video streaming can enhance bandwidth utilization by enabling
simultaneous video transmission to multiple users over shared wireless
channels. The existing network management schemes mainly rely on the sequential
buffering principle and general quality of experience (QoE) model, which may
deteriorate QoE when users' swipe behaviors exhibit distinct spatiotemporal
variation. In this paper, we propose a digital twin (DT)-based network
management scheme to enhance QoE. Firstly, user status emulated by the DT is
utilized to estimate the transmission capabilities and watching probability
distributions of sub-multicast groups (SMGs) for an adaptive segment buffering.
The SMGs' buffers are aligned to the unique virtual buffers managed by the DT
for a fine-grained buffer update. Then, a multicast QoE model consisting of
rebuffering time, video quality, and quality variation is developed, by
considering the mutual influence of segment buffering among SMGs. Finally, a
joint optimization problem of segment version selection and slot division is
formulated to maximize QoE. To efficiently solve the problem, a
data-model-driven algorithm is proposed by integrating a convex optimization
method and a deep reinforcement learning algorithm. Simulation results based on
the real-world dataset demonstrate that the proposed DT-based network
management scheme outperforms benchmark schemes in terms of QoE improvement.Comment: 13 pages, 12 figure
Random Linear Network Coding for 5G Mobile Video Delivery
An exponential increase in mobile video delivery will continue with the demand for higher resolution, multi-view and large-scale multicast video services. Novel fifth generation (5G) 3GPP New Radio (NR) standard will bring a number of new opportunities for optimizing video delivery across both 5G core and radio access networks. One of the promising approaches for video quality adaptation, throughput enhancement and erasure protection is the use of packet-level random linear network coding (RLNC). In this review paper, we discuss the integration of RLNC into the 5G NR standard, building upon the ideas and opportunities identified in 4G LTE. We explicitly identify and discuss in detail novel 5G NR features that provide support for RLNC-based video delivery in 5G, thus pointing out to the promising avenues for future research
Design and analysis of stream scheduling algorithms in distributed reservation-based multimedia systems
Ph.DDOCTOR OF PHILOSOPH
Instantly Decodable Network Coding: From Point to Multi-Point to Device-to-Device Communications
The network coding paradigm enhances transmission efficiency by
combining information
flows and has drawn significant attention in information theory,
networking, communications
and data storage. Instantly decodable network coding (IDNC), a
subclass of network coding,
has demonstrated its ability to improve the quality of service of
time critical applications
thanks to its attractive properties, namely the throughput
enhancement, delay reduction,
simple XOR-based encoding and decoding, and small coefficient
overhead. Nonetheless, for
point to multi-point (PMP) networks, IDNC cannot guarantee the
decoding of a specific new
packet at individual devices in each transmission. Furthermore,
for device-to-device (D2D)
networks, the transmitting devices may possess only a subset of
packets, which can be used
to form coded packets. These challenges require the optimization
of IDNC algorithms to be
suitable for different application requirements and network
configurations.
In this thesis, we first study a scalable live video broadcast
over a wireless PMP network,
where the devices receive video packets from a base station. Such
layered live video has a
hard deadline and imposes a decoding order on the video layers.
We design two prioritized
IDNC algorithms that provide a high level of priority to the most
important video layer
before considering additional video layers in coding decisions.
These prioritized algorithms
are shown to increase the number of decoded video layers at the
devices compared to the
existing network coding schemes.
We then study video distribution over a partially connected D2D
network, where a group
of devices cooperate with each other to recover their missing
video content. We introduce
a cooperation aware IDNC graph that defines all feasible coding
and transmission conflictfree
decisions. Using this graph, we propose an IDNC solution that
avoids coding and
transmission conflicts, and meets the hard deadline for high
importance video packets. It is
demonstrated that the proposed solution delivers an improved
video quality to the devices
compared to the video and cooperation oblivious coding schemes.
We also consider a heterogeneous network wherein devices use two
wireless interfaces to
receive packets from the base station and another device
concurrently. For such network,
we are interested in applications with reliable in-order packet
delivery requirements. We
represent all feasible coding opportunities and conflict-free
transmissions using a dual interface
IDNC graph. We select a maximal independent set over the graph by
considering dual
interfaces of individual devices, in-order delivery requirements
of packets and lossy channel
conditions. This graph based solution is shown to reduce the
in-order delivery delay
compared to the existing network coding schemes.
Finally, we consider a D2D network with a group of devices
experiencing heterogeneous
channel capacities. For such cooperative scenarios, we address
the problem of minimizing
the completion time required for recovering all missing packets
at the devices using IDNC
and physical layer rate adaptation. Our proposed IDNC algorithm
balances between the
adopted transmission rate and the number of targeted devices that
can successfully receive
the transmitted packet. We show that the proposed rate aware IDNC
algorithm reduces the
completion time compared to the rate oblivious coding scheme
Seamless, reliable, video multicast in wireless ad hoc networks
A wireless ad hoc network is a self-organized and dynamically reconfigurable wireless network without central administration and wired infrastructure. Nodes in a wireless ad hoc network can instantly establish a communication structure while each node moves in an arbitrary manner. A wireless ad hoc network is useful for mobile nodes working in a group to accomplish certain tasks. On the other hand, multicast is a very useful and efficient means of supporting group-oriented applications. Multicast is an essential technology for many applications such as video distribution and group video conferencing, data dissemination, disaster relief and battlefield.
Video multicasting over wireless ad hoc networks is bandwidth-efficient compared to multiple unicast sessions. However, video multicasting poses great challenges over wireless ad hoc networks. Video packets are both delay and loss sensitive. In addition, due to nodes mobility, the topology of wireless ad hoc networks is frequently changed. As a result, the established links are continuously broken, causing quality loss and interruption in the received video signal. Other challenges include limited battery life of wireless nodes and lower wireless network capacity compared to wired networks.
Video multicast over wireless ad hoc networks has been an active area in recent years. The main objective of these studies is to improve the quality of the received video by exploiting the error resilience properties of Multiple Description Coding (MDC) along with multiple paths. In other words, MD video is encoded and transmitted over two different paths to each destination node. If only one path is broken, packets corresponding to the other description on the other path can still arrive at the destination node on time.
Layered Coding (LC) and Multiple Description Coding (MDC) have been proposed as video source coding techniques that are robust against inevitable transmission errors. In contrast to MDC, LC encodes a media source into two or more sub-streams, known as layers, one base layer and several enhancement layers. The base layer can be decoded to provide a basic quality of the received video while the enhancement layers are mainly used to refine the quality of the video that is reconstructed from the base layer. If the base layer is corrupted, the enhancement layers become useless, even if they are received correctly. Therefore, the base layer is critically important and is usually highly protected. For MDC, however, these sub-streams are of equal importance in the sense that each sub-stream, also called a description, can be decoded independently to produce a signal of basic quality. When more descriptions are received, the decoder can gradually increase the quality.
One main problem of video multicasting for heterogeneous destinations is the assignment of video descriptions and the construction of multicast tree. However, the assignment of MD video and the construction of multicast tree can greatly affect the user satisfaction (i.e., affect the quality of the received video). In this thesis, we introduce novel approaches to improve the user satisfaction for a set of heterogeneous multicast destinations. The main idea of our approaches is to employ the independent-description property of MDC along with multiple multicast trees. However, many questions are raised: How multiple multicast trees should be constructed? And how MD video should be assigned? Is it better to construct multiple multicast trees first and then assign the video descriptions? Or is it better to assign the video descriptions first and we then construct multiple multicast trees? Should we perform that in a distributed manner or in a centralized one?
To answer these questions, we propose different algorithms to construct multiple multicast trees and to assign MD video. The proposed algorithms are: Serial MDC, Distributed MDC, and Centralized MDC. Serial MDC constructs multiple paths, to each destination, and assigns a different video description to each of them. After that, it constructs multiple multicast trees. Distributed MDC assigns MD video and constructs multiple multicast trees in parallel and in distributed fashion. In Centralized MDC, the assignment of MD video and the construction of multiple multicast trees are performed in a centralized manner. However, Centralized MDC first constructs multiple multicast trees and then assigns different video description to each multicast tree. We evaluate and compare our proposed algorithms Under different network conditions. For example, Network size, and multicast group size. Simulation results demonstrate that, indeed, the way of multicast trees construction and the assignment of MD video can greatly affect the user satisfaction. In addition, simulation results show that MDC can achieve higher user satisfaction compared to LC with a small cost in terms of number of pure forwarders nodes, bandwidth utilization, and aggregate tree delay.
Furthermore, we use our proposed algorithms to develop different multicast protocols for video multicast over wireless ad hoc networks. Specifically, we propose four protocols, namely, Centralized MDMTR (Multiple Disjoint Multicast Trees Routing), Sequential MDMTR, Distributed MDMTR, and Neighbor-aware MDMTR protocols. These protocols take many issues into consideration, rejoining and joining a multicast group, multicast trees maintenance, and mobility of nodes, for example. We evaluate the performance of our proposed protocols and compare them under different network conditions. For example, multicast group size, and mobility of nodes. Simulation results demonstrate that our protocols perform well compared to other protocols in the literature
Queue stability analysis in network coded wireless multicast.
In this dissertation queue stability in wireless multicast networks with packet erasure channels is studied. Our focus is on optimizing packet scheduling so as to maximize throughput. Specifically, new queuing strategies consisting of several sub-queues are introduced, where all newly arrived packets are first stored in the main sub-queue on a first-come-first-served basis. Using the receiver feedback, the transmitter combines packets from different sub-queues for transmission. Our objective is to maximize the input rate under the queue stability constraints. Two packet scheduling and encoding algorithms have been developed. First, the optimization problem is formulated as a linear programming (LP) problem, according to which a network coding based optimal packet scheduling scheme is obtained. Second, the Lyapunov optimization model is adopted and decision variables are defined to derive a network coding based packet scheduling algorithm, which has significantly less complexity and smaller queue backlog compared with the LP solution. Further, an extension of the proposed algorithm is derived to meet the requirements of time-critical data transmission, where each packet expires after a predefined deadline and then dropped from the system. To minimize the average transmission power, we further derive a scheduling policy that simultaneously minimizes both power and queue size, where the transmitter may choose to be idle to save energy consumption. Moreover, a redundancy in the schedules is inadvertently revealed by the algorithm. By detecting and removing the redundancy we further reduce the system complexity. Finally, the simulation results verify the effectiveness of our proposed algorithms over existing works