JENNA: A Jamming Evasive Network-Coding Neighbor-Discovery Algorithm for Cognitive Radio Networks

In this paper we address the problem of neighbor discovery in cognitive radio networks. Cognitive radios operate in a particularly challenging wireless environment. In such an environment, besides the strict requirements imposed by the opportunistic co-existence with licensed users, cognitive radios may have to deal with other concurrent (either malicious or selfish) cognitive radios which aim at gaining access to most of the available spectrum resources with no regards to fairness or other behavioral etiquettes. By taking advantage of their highly flexible radio devices, they are able to mimic licensed users behavior or simply to jam a given channel with high power. This way these concurrent users (jammers) are capable of interrupting or delaying the neighbor discovery process initiated by a normal cognitive radio network which is interested in using a portion of the available spectrum for its own data communications. To solve this problem we propose a Jamming Evasive Network-coding Neighbor-discovery Algorithm (JENNA) which assures complete neighbor discovery for a cognitive radio network in a distributed and asynchronous way. We compare the proposed algorithm with baseline schemes that represent existing solutions, and validate its feasibility in a single hop cognitive radio network

JENNA: a jamming evasive network-coding neighbor-discovery algorithm for cognitiveradio networks [Dynamic Spectrum Management]

Cognitive radios operate in a particularly challenging wireless environment. Besides the strict requirements imposed by opportunistic coexistence with licensed users, cognitive radios may have to deal with other concurrent (either malicious or selfish) cognitive radios that aim at gaining access to the available spectrum resources with no regard to fairness or other behavioral etiquettes. By taking advantage of their highly flexible RF front-ends, they are able to mimic a licensed user's behavior or simply jam a given channel with high power. This way these concurrent users (jammers) are capable of interrupting or delaying the neighbor discovery process initiated by a cognitive radio, which is interested in using a portion of the available spectrum for its own data communications. To solve this problem we propose a Jamming Evasive Network-coding Neighbor-Discovery Algorithm (JENNA), which ensures complete neighbor discovery for a cognitive radio network in a distributed and asynchronous way. We compare the proposed algorithm with baseline schemes that represent existing solutions, and validate its feasibility in a single-hop cognitive radio network

Cooperative Detection and Spectrum Reuse using a Network Coded Cognitive Control Channel

Among the major challenges in the development of effective dynamic spectrum access techniques are the realization of the control channel, the detection of primary users, and the efficient use of the available spectrum. Most of the previous work in this field has addressed only a subset of these issues. In a previous paper we proposed a distributed multi-channel medium access strategy based on a network coded cognitive control channel (NC4), which addresses the issues of the control channel and the spectrum efficiency. In this paper we apply that solution to dynamic spectrum access scenarios. The key feature of this work is the introduction of a cooperative primary user detection strategy which effectively enables the detection and reuse of unused portions of the licensed spectrum. The complete system resulting from this extension, which we call NC4-DSA, has the merits of being fully distributed, not requiring spectrum resources statically allocated for control purposes, and being very suitable for implementation thanks to the use of simple and low cost detection strategies such as energy detection. Furthermore, as we will show in our performance evaluation, it enables efficient opportunistic spectrum access with minimal interference to primary users

Dynamic Spectrum Access Using a Network Coded Cognitive Control Channel

In this paper we propose a Dynamic Spectrum Access scheme which allows the users to opportunistically and efficiently access the channels available for communications. It addresses the following important aspects of opportunistic spectrum access: 1) implementation of the control channel, 2) multi-channel medium access control, 3) primary user detection, and 4) secondary reuse of spectrum unused by primary users. The main features of the scheme are that it is completely distributed, it does not need dedicated spectrum resources for control purposes, but rather leverages on a virtual control channel which is implemented using Network Coding techniques, and it exploits a cooperative detection strategy to identify unused spectrum. Due to these aspects, our proposal represents a significant improvement with respect to existing Dynamic Spectrum Access solutions. We carry out an evaluation study of the proposed solution to assess its performance with respect to different system and scenario parameters; the obtained results show that the proposed solution is feasible, capable of providing satisfactory performance, and suitable for implementation in real systems

On channel aware routing policies in shallow water acoustic networks

In this paper we consider shallow-water acoustic networks, and propose a routing policy that exploits qualitative information about the behavior of the channel, given some key parameters such as the position and depth of the source, the location of the receiver and the sea bottom profile. Our policy is based on a set of several synthetic channel realizations obtained using the Bellhop ray tracing software, where the channel variability is obtained via random perturbations of the sound speed profile and of the sea surface shape. The channel realizations are translated into Signal-to-Noise Ratio (SNR) statistics: the relay sought must comply with the constraint that the SNR exceeds a threshold with a given probability. We show that these SNR statistics allow the routing policies to identify geographic areas where a high SNR is more likely to occur. Our policy is compared to shortest-path routing (obtained via a centralized algorithm and oblivious of channel statistics), and to an optimal, genie-aided policy that always picks the best relay which complies to the SNR constraint. Results show that channel-aware policies consistently outperform the shortest path policy, and that our heuristic policy performs very close to the optimal one in several scenarios

Multi-channel medium access using a virtual network coded control channel

In this paper we propose a Multi-Channel Medium Access scheme with the aim to enable efficient Dynamic Spectrum Access. Two are the remarkable features of our solution: first, it is completely distributed, and second, it does not need dedicated spectrum resources for control purposes, but rather it leverages on a virtual control channel which is implemented by having users exchange control information whenever they meet in a particular channel, and by retrieving the control information using Network Coding techniques. We carry out an evaluation study of the proposed solution to assess its performance with respect to different system and scenario parameters; the obtained results show that the proposed solution is feasible and suitable for implementation in real Dynamic Spectrum Access systems

A cluster formation protocol for cognitive radio ad hoc networks

In this paper we present a solution for the realization of large Cognitive Radio Networks. The solution features a spectrum-aware neighbor discovery and clustering scheme that works in conjunction with a network coded cognitive control channel in order to allow Cognitive Radio devices to opportunistically access the unused spectrum. We evaluate the performance of the proposed solution with respect to the characteristics of the formed clusters as well as the reliability of the dissemination of the control information within the cluster