Showing papers by "Abhijit Bhowmick published in 2018"

Multi slot-throughput tradeoff in an improved energy detector based faded cognitive radio network

Abstract: In this paper, the impact of a multi slot based cooperative spectrum sensing (CSS) on the performance of a cognitive radio (CR) network has been investigated. Each CR user, equipped with an improved energy detector (IED), uses a number of mini slots of the sensing time to perform the spectrum sensing. Each CR uses OR logic to combine the sub local decisions generated in each mini slot to obtain a local decision at CR level. Local decisions are sent to fusion centre (FC) over reporting channel. The FC obtains a final decision about the presence of primary user (PU) by combining the local decisions using a fusion rule: Majority or Maximal Ratio Combining. The performance of the CSS is assessed in terms of detection probability and false alarm probability considering both the sensing and reporting channels are Rayleigh faded. Furthermore, the impact of a number of sensing slots and IED parameter on throughput of CR network is also evaluated under the proposed spectrum sensing scenario. Impacts of several sensing parameters such as sensing channel SNR and reporting channel SNR on the performance of CR network are also evaluated. Performances of two fusion rules under study are compared. Effect of sensing error and synchronisation error is indicated. Further the study is extended for independent but non identically distributed (i.n.i.d.) Rayleigh faded channels as well as for a multiple PU scenario also.

Performance of an Energy harvesting Cooperative Cognitive Radio Network with Hybrid Spectrum Access Scheme

Abstract: In this paper, a hybrid spectrum access scheme is investigated for a relay based energy harvesting cooperative cognitive radio (CR) network In the considered network model, a relay harvests energy from RF signal of primary user (PU) as well as from RF signal of CR also The relay node forwards the CR data to the respective destination and also cooperates in PU transmission as well The CR follows a hybrid spectrum access scheme, ie, it employs an underlay scheme of co-existence if PU is found to be present in the given channel else it switches to the overlay scheme of transmission In overlay scheme, a CR transmits with maximum transmission power while in underlay scheme, it controls its transmission power based on the knowledge of channel state information of the link between CR and PU receiver, to limit the interference at PU receiver Three new ratio parameters namely, PU–CR time allocation parameter, PU two hop transmission parameter and CR two hop transmission parameter are considered to model the cooperative transmission of PU and CR network where the parameter β takes care of the allocated time for PU and CR transmission and the other two parameters θ and ϕ take care of two hop transmission for PU and CR respectively Analytical expressions of combined throughput of a CR and PU are developed under the considered network scenario The performance is investigated in terms of combined throughput of CR, combined throughput of PU, and the overall network throughput for several sensing parameter and new ratio parameters

Wireless Network Security Using Intrusion Detection System

Abstract: A major problem for networked systems is hostile trespassers. These trespassers may be users or software used by users to trespass a network. Trespasses may be in the form of authorized logon to a machine or acquisition of privileges and performance of actions beyond that have been authorized when in the case of an authorized user. To protect these resources, we need to detect the intrusions or intended intrusions, as absolute security may not be possible. Automatic detection of attacks [1] requires some kind of machine learning approach for the detection purposes. For machine learning to be successful, the machines have to be trained for known types of attacks.

Performance of Full Duplex Relaying with Dual Antenna and Soft Combining

Abstract: The performance of a full-duplex (FD) relaying system is investigated in this paper. The relay is equipped with two antennas (both are trans-receiver). The energy constrained relay is powered by RF energy harvesting. A time-switching architecture is adopted to make communication between a source and a destination. Information received at the destination from both the trans-receiver is combined using a soft combining technique, i.e., Maximal Ratio Combining (MRC). The performance of two protocols, decode-and- forward (DF) relaying and amplify-and-forward (AF), are also studied and compared. It is found that use of double antenna instead of single antenna based transmission at the relay improves the performance significantly. The impact of MRC on the throughput performance is noticeable.