CCACK: Efficient Network Coding Based Opportunistic Routing Through Cumulative Coded Acknowledgments

Abstract

Abstract-The use of random linear network coding (NC) has significantly simplified the design of opportunistic routing (OR) protocols by removing the need of coordination among forwarding nodes for avoiding duplicate transmissions. However, NC-based OR protocols face a new challenge: How many coded packets should each forwarder transmit? To avoid the overhead of feedback exchange, most practical existing NC-based OR protocols compute offline the expected number of transmissions for each forwarder using heuristics based on periodic measurements of the average link loss rates and the ETX metric. Although attractive due to their minimal coordination overhead, these approaches may suffer significant performance degradation in dynamic wireless environments with continuously changing levels of channel gains, interference, and background traffic.In this paper, we propose CCACK, a new efficient NCbased OR protocol. CCACK exploits a novel Cumulative Coded ACKnowledgment scheme that allows nodes to acknowledge network coded traffic to their upstream nodes in a simple way, oblivious to loss rates, and with practically zero overhead. In addition, the cumulative coded acknowledgment scheme in CCACK enables an efficient credit-based, rate control algorithm. Our evaluation shows that, compared to MORE, a state-of-theart NC-based OR protocol, CCACK improves both throughput and fairness, by up to 20x and 124%, respectively, with average improvements of 45% and 8.8%, respectively.

Network Coding Techniques for Wireless and Sensor Networks

“…MORE also assumes that the links are independent, and it does not consider the correlation between the links. The CCACK approach [28] solves these problems. In CCACK, nodes use cumulative coded acknowledgments, which allow nodes to acknowledge the coded received packets to their upstream nodes, using a single compressed feedback message, with almost zero cost.…”

“…The use of null-space in opportunistic routing suffers from a problem called the collective space problem [28]. Suppose that nodes r 3 , r 2 , and r 1 are sorted in increasing order of their distance from the destination node.…”

“…In order to solve this problem, the authors in [28] use separate buffers at each node i for the coefficient of the received packets from upstream nodes (B u ), the coefficient of sent coded packets (B w ), and the received innovative packets (B v ). When the node i overhears a coded packet from the downstream nodes, the node marks the coefficients in B u and B v , if their inner product with the recited null-space is equal to zero.…”

Cross-layered resource allocation in UWB noise-OFDM-based ad hoc surveillance networks

“…This single-radio multi-channel wireless radar-communications system is what we call the UWB noise-OFDM radar [7]. Multiple such radars can then form an ad hoc communication network to provide significant benefits in target detection and recognition, by taking advantage of multi-aspect and multi-look fusion techniques [8,9], and information dissemination through opportunistic routing [10]. Furthermore, by having multicarrier data communication within the same spectrum as the radar's transmit signal, a substantial increase in network capacity and bandwidth efficiency can be achieved.…”

On the packet loss correlation in wireless mesh networks

“…ExOR is the first implementation of an opportunistic routing protocol [2], with the caveat that nodes should coordinate their action to avoid transmissions of redundant packets. To address this problem, MORE [3], CCACK [6], GeoCode [11], CORE [7], exploit random linear network coding (RLNC) to reduce the coordination between nodes.…”