WPR.5 - Coding for Multi-Hop Wireless Networks

Objectives

Various aspects related to coding at the network and physical layer in multi-hop wireless networks will be addressed, aiming at providing better throughput, energy efficiency and resource utilization both in unicast and multicast communications. This situation requires the design of novel channel codes due to its specific features. Since coding at the network layer requires the design of different channel codes, rateless codes, distributed channel coding, and network coding can cooperate to provide efficient solutions to the problem, and they will be a key part of the research investigation. The research tasks are encouraged to investigate the applicability of their results to modern wireless standards, in particular Long Term Evolution (LTE) and LTE-Advanced.

Description of work

The work package is organized around the following tasks (s. below). For inter-work package cooperations natural candidates are WPR.4 (Iterative Techniques) WPR.8 (Scheduling Issues in Wireless Networks), WPR11 (Application of Network Coding to Opportunistic Networks), and WPR.6 (Coding Schemes for Relay Networks). To that end, joint work package meetings are envisioned.

Task TR5.1: Information Theoretic Aspects and Practical Coding Schemes for Network Coding

The focus will be on information theory for multi-hop networks. For instance, particular modern multi-terminal approaches in the realm of fading will be investigated, to define absolute limits on the considered networks. On the other hand, we plan to investigate practically implementable techniques that approach the theoretical limits within bounds that are provably not too far from the optimum.

Main players: CTTC, CNRS, FTW

Task TR5.2: Network Coding for Wireless Hyperlinks

In more complex networks, more elaborate network coding schemes have to be made available and the mixing of data can be done at many places, but also under the constraint of a multiple of arbitrary receivers. A combined and concerted investigation of these effects lies at the bottom of the network coding part of this task, specifically with respect to hyperlinks. In particular, it is important to investigate, how network coding and the routing/forwarding scheme cooperate. In volatile, mobile networks geographic routing is an interesting approach, since the storage requirements for routing tables are minimal. We are interested in combining this approach with network coding, in order to capitalize on the robustness and throughput gains of network coding.

Main players: LNT-TUM, CNIT

Task TR5.3: Erasure Coding on the Network Layer

This task addresses coding schemes on the network layer, but with the aim of combating erasures. These efficient schemes have to be found under additional restrictions of limited latency and limited transmission overhead, like for video transmission, gaming, or Voiceover-IP applications.

Main players: UCL, CNIT

Task TR5.4: Network Coding in Networks with Relays

Within wireless multi-hop networks or networks with relays, it has been shown that network coding can be applied with relative simple coding schemes. Moreover, iterative receiver structures can be applied to exploit additional information out of the additional mixed data of interior nodes or of relays. The design of distributed network-channel codes, in particular for the Multiple-Access Relay Channel (MARC) is central goal, as the MARC-model captures most difficulties encountered in practical networks, such as multi-access interference and distributed cooperation.

Main players: LNT-TUM, UCL