Abstract—This paper studies multiple relay selection schemes in two-hop cognitive relay networks to maximize the signal-to-noise ratio (SNR) of the secondary receiver. We first formulate the relay selection as a nonlinear integral programming, and then propose two suboptimal methods, greedy scheme

Abstract—In this paper, we investigate four different two-hop amplify and forward relay networks, which differ on the processing capabilities at the source, relay, and destination nodes. We derive new exact outage probability expressions where zero-forcing processing is performed at the following

Abstract—Carefully designed protocols can turn overheard interference into useful side information to allow simultaneous transmission of multiple communication flows and increase the spectral efficiency in interference-limited regime. We propose a novel scheme in a typical cell-edge scenario

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Relaying is found in Packet Radio and Ad-hoc networks whereby communications between mobile terminals are carried out in a distributed manner through intermediate relay nodes. When employed in a cellular network, this technique can be regarded as an Opportunity Driven Multiple Access (ODMA) scheme

-reinforcement scheme, we show how to strengthen the security between any two nodes by leveraging the security of other links. Finally, we present the random-pairwise keys scheme, which perfectly preserves the secrecy of the rest of the network when any node is captured, and also enables node-to-node authentication

investigation if there is more than one cooperative relay. We propose a novel scheme that alleviates these problems and provides diversity gains on the order of the number of relays in the network. Our scheme first selects the best relay from a set of available relays and then uses this “best ” relay

Cognitive radio is viewed as a novel approach for improving the utilization of a precious natural resource: the radio electromagnetic spectrum. The cognitive radio, built on a software-defined radio, is defined as an intelligent wireless communication system that is aware of its environment

Abstract—We consider using a buffer-aided relay to enhance security for two-hop half-duplex relay networks with an external eavesdropper. We propose a link selection scheme that adapts reception and transmission time slots based on channel quality, while considering both the two-hop transmission

-link of two-hop multimedia CDMA networks. In this envisioned network, the WTs (Wireless Terminals – portable devices used to transmit and/or receive electronic information via an air interface(s)) which cannot establish a direct link with the BS (at the required rates) seek the assistance of those WTs which