Janus Heide

Network Coding for Mobile Devices - Systematic Binary Random Rateless Codes

In this work we consider the implementation of Random Linear Network Coding (RLNC) on battery constrained mobile devices with low computational capabilities such as; sensors, mobile phones and Personal Digital Assistants (PDAs). It is non-trivial to create an efficient implementation of RLNC which is needed to ensure high throughput, low computational requirements and energy consumption. As a consequence there does not, to the best of our knowledge, exist any such implemen- tation for mobile device that allow for throughput close to what can be achieved in e.g. Wireless Local Area Network (WLAN). In this paper we propose to base RLNC on the binary Galois field and to use a systematic code. We have implemented this approach in C++ and Symbian C++ and achieve synthetic encoding/decoding throughput of up to 40/30 MB/s on a Nokia N95-8GB mobile phone and 1.5/1.0 GB/s on a high end laptop. Index Terms—Mobile devices, Network coding, Reliable Mul- ticast. I. INTRODUCTION A large body of existing literature (1) treats the theoretical benefits of Network Coding (NC). However, the costs of implementing NC in terms computational overhead, memory consumption or network usage is often not considered. In this work we consider the implementation of RLNC on mobile bat- tery constrained devices with low computational capabilities, such as sensors, mobile phones or PDAs. The computations performed using RLNC is based on finite fields arithmetic also known as Galois fields. From a coding perspective the field size, q, used should be large to ensure that coded packets are linearly independent, additionally increasing the size of the field elements is advantageous as this reduces the number of

Kodo: an open and research oriented network coding library

This paper introduces theKodo network coding library. Kodo is an open source C++ library intended to be used in practical studies of network coding algorithms. The target users for the library are researchers working with or interested in network coding. To provide a research friendly library Kodo provides a number of algorithms and building blocks, with which new and experimental algorithms can be implemented and tested. In this paper we introduce potential users to the goals, the structure, and the use of the library. To demonstrate the use of the library we provide a number of simple programming examples. It is our hope that network coding practitioners will use Kodo as a starting point, and in time contribute by improving and extending the functionality of Kodo.

Synchronized multimedia streaming on the iPhone platform with network coding

This paper presents the implementation of synchronized multimedia streaming for the Apple iPhone platform. The idea is to stream multimedia content from a single source to multiple receivers with direct or multi-hop connections to the source. First we look into existing solutions for video streaming on the iPhone for point-to-point architectures. After acknowledging their limitations, we propose a solution based on network coding to efficiently and reliably deliver the multimedia content to many devices in a synchronized manner. Then we introduce an application that implements this technique on the iPhone. We also present our testbed which consists of 16 iPod Touch devices to showcase the capabilities of our application.

Cautious view on network coding — From theory to practice

Energy consumption has been mostly neglected in network coding (NC) research so far. This work investigates several different properties of NC that influence the energy consumption and thus are important when designing NC systems for battery-driven devices. Different approaches to the necessary implementation of coding operations and Galois fields arithmetic are considered and complexity expressions for coding operations are provided. We also benchmark our own mobile phone implementation on a Nokia N95 under different settings. Several NC strategies are described and compared, furthermore expressions for transmission times are developed. It is also shown that the use of NC introduces a tradeoff between reduction in transmission time and increase in energy consumption.

Implementation of Network Coding for Social Mobile Clouds [Applications Corner]

In this work, the authors advocated for the need of social elements to make egoistic users cooperate with each other in certain situations. After discussing different forms of cooperation (specifically forced, altruistic, technology-enabled, and socially enabled), we introduced a number of example use cases. As discussed, the technology-enabled cooperation will cover a large number of these use cases. Furthermore, network coding is a technology that will make user cooperation more efficient and attractive to users. But in cases where the technology-enabled cooperation is not attractive enough, the social elements will play an important role. By means of social networks, examples were given of how social benefits can be created to persuade users to cooperate. More examples will be found in the future as social networking technology develops, but the initial examples underline the feasibility of that approach.

CATWOMAN: Implementation and Performance Evaluation of IEEE 802.11 Based Multi-Hop Networks Using Network Coding

This paper investigates the performance of network coding for an IEEE802.11 enabled meshed network. By means of basic setups the impact of the medium access control in combination with network coding is investigated. In contrast to prior work the network coding approach is tailored to commercial WiFi hardware without any special tweaks. The implementation of network coding is done on top of an existing routing scheme known as B.A.T.M.A.N. which has some inherent advantages to support network coding. We present schemes to utilize the B.A.T.M.A.N. routing to detect coding opportunities. One finding is that the performance gain for the well known Alice and Bob scenario using network coding is 60% compared to a pure relaying scheme. The software used in the presented measurement campaign is made publicly available.

PictureViewer - A mobile application using network coding

This paper looks into the implementation details of network coding for a mobile application running on commercial mobile phones. The mobile application coined PictureViewer can convey pictures from one source device to many neighboring devices using WiFi. The advantage of network coding in this context is that the source devices only needs a minimal amount of knowledge about the targets received packets and therefore only a minimal amount of feedback is needed to ensure reliable data delivery. The implemented network coding algorithms are tailored to be fast and energy efficient on commercial mobile phones. The goal of the paper is therefore to investigate those algorithms and to demonstrate that network coding can be deployed on state of the art mobile phones.

On-the-Fly Packet Error Recovery in a Cooperative Cluster of Mobile Devices

This paper investigates the possibility of packet error recovery in a cooperative cluster of mobile devices. We assume that these devices receive data from a broadcast transmission on their primary network interface (e.g. LTE network), and they are using a secondary network interface (e.g. ad hoc WLAN network) to form a cooperative cluster in order to exchange missing data packets among each other. Our goal is to devise a protocol that minimizes the number of packets exchanged on the secondary network whilst maximizes the number of packet errors recovered on the primary network. Moreover, we aim to repair the packet losses on-the-fly (as the data is being received), which also imposes real-time constraints on the protocol. We propose a solution based on random linear network coding to form cooperative clusters of mobile devices to facilitate the efficient exchange of information among them. We also introduce a demo application that implements this technique on Nokia phones. Then we present our testbed and the collected measurement results in order to evaluate the performance of our protocol.

Multimedia distribution using network coding on the iphone platform

This paper looks into the implementation details of random linear network coding on the Apple iPhone and iPod Touch mobile platforms for multimedia distribution. Previous implementations of network coding on this platform failed to achieve a throughput which is sufficient to saturate the WLAN interface. In addition to previous works we compare new implementations based on two different Galois fields: GF(28) and GF(2). Using the binary Galois field allows us to ensure high throughput and low computational requirements on mobile devices with limited resources. We have implemented this approach and achieved synthetic encoding/decoding throughput of up to 36/29 MB/s on a third generation iPod Touch 32GB which exceeds the results of other researchers by two orders of magnitude.

MBMS with User Cooperation and Network Coding

In this paper user cooperation with network coding is applied to MBMS (Multimedia broadcast/multicast service) where Raptor codes are currently used. User cooperation together with network coding is used to save bandwidth and improve user perceived QoS for broadcast/multicast services in the future mobile communication networks. The proposed approach is tailored to LTE networks and extended with local cooperation. The simulation results show that local retransmissions can reduce the amount of redundant information on the cellular link with up to