Instantly decodable network codes for cooperative index coding problem over general topologies

Abstract

We consider a group of n wireless clients and a set of k messages. Each client initially holds a subset of messages and is interested in an arbitrary subset of messages. Each client cooperates with other clients to obtain the set of messages it wants by exchanging instantly decodable network coded (IDNC) packets. This problem setting is known as the cooperative index coding problem. Clients are assumed to be connected through an arbitrary topology. In the absence of any known algorithm to complete the exchange of packets for general network topologies, we propose a greedy algorithm to satisfy the demands of all the clients with the aim of reducing the mean completion time. Our algorithm, in a completely distributed fashion, decides which subset of clients should transmit at each round of transmission and which messages should be coded together by each transmitting client to generate an IDNC packet. The algorithm encourages transmissions which are decodable for a larger number of clients and attempts to avoid collisions. We evaluate the performance of our algorithm via numerical experiments.

Instantly decodable network coding for real-time device-to-device communications

“…Recently, some works [20][21][22][23] begin to address the delay reduction problem in IDNC-enable D2D network configuration. While the authors in [20,21,23] design algorithm for the sum decoding delay reduction, references [20,22] propose schemes for the completion time reduction.…”

“…While the authors in [20,21,23] design algorithm for the sum decoding delay reduction, references [20,22] propose schemes for the completion time reduction. However, these works intersect as they directly extend the delay reduction PMP schemes, known to be NP-hard, to the D2D setting without considering the complexity issue for such battery-powered networks.…”

“…Due to the dynamic nature of the links, finding a schedule of transmission that optimally reduce the decoding delay for the entire recovery phase, prior to its start, is intractable. A commonly adopted technique [9,10,12,20,21,23] is to minimize the decoding delay on-line, i.e., at each recovery transmission. D j (κ i , n) is define as the total decoding delay experienced by device j from the beginning of the recovery phase until the transmission at time n in which device i is transmitting the packet combination κ i .…”

Rate Aware Instantly Decodable Network Codes

“…For a schedule S of message combination κ(t) and transmit rates R(t), 1 ≤ t ≤ |S|, the completion time C u of user u can be expressed as: 4) where N (κ(t)) is the size of the message combination κ and n u (S) is the first transmission index verifying W = ∅. Since the messages are mixed using binary XOR, then the size of any message mixture is N .…”

“…Recently, Instantly Decodable Network Coding (IDNC) captivated a significant number of works [4]- [12] thanks to its fast decoding potential, essential for real-time applications, such as multimedia streaming [13]. In IDNC, the coded message A part of this paper [1] combinations need to be decoded at their reception instant and cannot be stored for future decoding.…”