Cognitive radio plays a vital role in wireless communication. The cognitive radio composed of a transceiver which is used to check the channel vacancy for communication and avoids busy channels by shifting into unused channel. The scope for spectrum vacancy and area of coverage is increased by using cognitive radio. In cooperative relay network to transmit the primary traffic the primary users ...

A RFID group scanning protocol enables a RFID reader to produce a proof of co-existence of multiple RFID tags. This type of protocol is also referred to as yoking-proof, grouping-proof and co-existence proof. In this letter, we show that all of the previous group scanning protocols are vulnerable to relay attack. key words: yoking-proof, grouping-proof, co-existence-proof, relay attack

Proton relays are known to increase reaction rates for H2 evolution and lower overpotentials in electrocatalytic reactions. In this report we describe two electrocatalysts, [Fe4N(CO)11(PPh3)] (1 ) which has no proton relay, and hydroxyl-containing [Fe4N(CO)11(Ph2P(CH2)2OH)] (2 ). Solid state structures indicate that these phosphine-substituted clusters are direct analogs of [Fe4N(CO)12] where o...

Proton relays are known to increase reaction rates for H2 evolution and lower overpotentials in electrocatalytic reactions. In this report we describe two electrocatalysts, [Fe4N(CO)11(PPh3)]- (1-) which has no proton relay, and hydroxyl-containing [Fe4N(CO)11(Ph2P(CH2)2OH)]- (2-). Solid state structures indicate that these phosphine-substituted clusters are direct analogs of [Fe4N(CO)12]- wher...

This paper presents a method to improve the spectral utilization in Multi-hop Relay (MMR) networks. Co-channel interference is considered as a parameter to analyze the performance of MMR (IEEE 802.16j) based relay networks. Frequency reuse technique is a way to improve the spectral utilization. Since the same frequency band is used by Relay stations and Base Station, co-channel interference wit...

In this paper, Ultra-wideband (UWB) multiple access relay channel with correlated noises at the relay and receiver is investigated. We obtain outer and inner bounds for the IEEE 802.15.3a UWB multiple access relay channel, and also, a diversity gain bound. Finally, we evaluate some results numerically and show that noise correlation coefficients play important role in determining relay position.

In this paper, we analyze the effect of resource allocation in two-relay networks with mixed relaying protocol. We assume that two relay nodes exist between the source node and destination node, and one relay node adopts decode-and-forward (DF) relaying protocol and the other one uses amplify-andforward (AF) relaying protocol. Differential modulation scheme is applied for all cases to bypass ch...

This paper analyzes the performance of a dualhop amplify-and-forward (AF) cooperative relay network in the presence of direct link between the source and destination and multiple co-channel interferences (CCIs) at the relay. Specifically, we derive the new analytical expressions for the moment generating function (MGF) of the output signal-to-interference-plus-noise ratio (SINR) and the average...

In this paper, an interval approach is presented to achieve perfect selectivity and maximum sensitivity in distance relay zones, considering uncertainties. For this purpose, first, the uncertainties affecting the settings of the three zones of a distance relay are discussed. Then, by using the Monte-Carlo simulation, the uncertainties are modelled and the impedances seen by the distance relay a...

This paper studies optimal power allocation to minimize symbol error rate (SER) of amplify-and-forward cooperative diversity networks. First, we analytically solve optimal power allocation problem to minimize SER for three different scenarios, namely, multi-branch single-relay, single-branch multi-relay and multi-branch multi-relay cooperative diversity networks, all subject to a given total re...