Sharifah Kamilah Syed Yusof

Energy detection sensing based on GNU radio and USRP: An analysis study

Cognitive radio wireless networks are an emerging communication paradigm to effectively address spectrum scarcity challenge. Spectrum sensing plays a paramount role in cognitive radio, which is widely agreed to be the most promising method for alleviating the symptom of RF spectral scarcity. Dynamic access of unused spectrum via a cognitive radio asks for flexible radio circuits that can work at an arbitrary radio frequency. In this paper, we analyze the performance of spectrum sensing on GNU Radio system with USRP. We investigating spectrum scarcity and proposed the algorithm that performed and measuring the energy of Rx signal in a fixed bandwidth, W, over an observation time window, T. The results presented that it can detected of primary user signal over the fixed bandwidth which occupied the spectrum.

Performance Study of Wireless Body Area Network in Medical Environment

The advanced developments in sensors and wireless communications devices have enabled the design of miniature, cost-effective, and smart physiological sensor nodes. One of the approaches in developing wearable health monitoring systems is the emerging of wireless body area network (WBAN). IEEE 802.15.4 provides low power, low data rate wireless standard in relation to medical sensor body area networks. In the current study, the star network topology of 802.15.4 standard at 2.4 GHz had been considered for body area network (BAN) configured in beacon mode. The main consideration is in the total data bits received by all the nodes at the coordinator and flight times of a data packet reaching its destination. In this paper we discussed on wireless technologies that can be used for medical applications and how they perform in a healthcare environment. The low-rate Wireless Personnel Area Network (WPAN) is being used to evaluate its suitability in medical application.

Experimental study of OFDM implementation utilizing GNU Radio and USRP - SDR

A Software Defined Radio (SDR) is a radio which can tune to any frequency band, transmit and receive different modulations and different physical parameters across a large frequency spectrum by using a programmable hardware and powerful software. An SDR performs significant amounts of signal processing in a general purpose computer, or a reconfigurable piece of digital electronics or the combination of both. In this paper, we seek to explore the viability of using GNU Radio; an open source SDR implementation and the Universal Software Radio Peripheral (USRP); an SDR hardware platform, to transmit and receive the OFDM radio signal with QPSK and BPSK modulation. Quality of Service (QoS) in terms of Packet Received Ratio (PRR) on the data transmitted will then be investigated and analyzed.

Integration of Cooperative Sensing and Transmission

In this article, some aspects of cognitive radio (CR) technologies and cooperation strategies are discussed. The findings show that cooperative sensing enhances decision making by collaborating cognitive users (CUs). Primary users (PU) protection increases by OR rule and opportunistic access increases for CUs if collaborated using AND rule. It can also be observed that cooperative relaying benefits from path-loss saving, power gain due to the fact that the relay may add additional transmit power, and diversity gain in the presence of fading. In addition, the network performance is also enhanced by the increase in achievable data rates when using cooperative relay when compared with the rates achieved without relay. Cooperative communication technique can further enhance the transmission capacity of a communication system, while CR technique can improve the spectrum utilization ratio. Doubtless, the integration of the two technologies will have a great impact on network architecture, terminals, service models, and applications of future wireless mobile communication.

Correlative coding with clipping and filtering technique in OFDM systems

The major setbacks of orthogonal frequency multiplexing (OFDM) are its peak-to-average power ratio (PAPR) and intercarrier interference (ICI). The occurrence of these factors restricts its application. Here, the clipping and filtering PAPR reduction technique is being investigated to reduce the PAPR and out-of-band radiation simultaneously by implementing correlative coding. This paper focuses on the preliminary measurement study that was carried out. It is shown through simulation that the collaboration of these techniques gives a reasonable PAPR reduction and improves the out-of-band radiation.

Intelligent optimization of node coordination in Wireless Sensor Network

This paper presents a method which intelligently determines the optimum node coordination of sensor nodes topology. The topology is in linear array, aimed for beamforming in Wireless Sensor Networks (WSNs). The array is constructed in random sensor node deployment. The selected nodes should align similar to a uniform linear array (ULA) to minimize the position errors which will improve the beamforming performance (gain, transmission range and characteristics). Instead of utilizing random beamforming which needs a large number of sensor nodes to interact with each other and form a narrow radiation beam, the proposed approach is emphasized to only a number of sensor nodes which can construct a linear array. Beamforming technologies can increase the system performance, increase the transmission range and control the directionality of the reception or transmission of a signal. The proposed work utilizes beamforming technique by using ULA to establish a communication link in a WSN.

Interference aware channel assignment (IACA) for cognitive wireless mesh networks

In this paper, we present the end-to-end interference aware concept of Cognitive wireless mesh network (CWMN). CWMN is the leading upcoming technology with the advantage of cognitive radio (CR). We demonstrate that the end-to-end interference model has the ability to perform better from SINR base model. To enhance the utilization of the unused spectrum the channel selection strategy should have some awareness mechanism to avoid interference. In this paper, novel interference aware channel assignment (IACA) algorithm is proposed. The end-to-end delay, packet delivery ratio and the throughput is used to estimate the performance of the proposed algorithm. The numerical results demonstrate that the proposed algorithm is closer to the optimum resource utilization.

Circular Collaborative Beamforming for Improved Radiation Beampattern in WSN

This paper presents a novel collaborative beamforming (CB) method of wireless sensor network (WSN) by organizing sensor node location in a circular arrangement. Appropriate selection of active CB nodes and cluster is needed each time to perform CB. The nodes are modeled in circular array location in order to consider it as a circular antenna array (CAA). This newly proposed circular collaborative beamforming (CCB) is further presented to solve two different objectives, that is, sidelobe level (SLL) suppression and first null beamwidth (FNBW). Analyses obtained are compared to those from previous work. The findings demonstrate a better CB performance of intelligent capability, and the difference is shown in normalized power characteristic.

Sensing period considerations in fading environment for multimedia delivery in cognitive Ultra Wideband system

Spectrum scarcity and the inefficiency in its usage have necessitates the use of Cognitive Radio (CR) technology to exploit the existing wireless spectrum opportunistically. Spectrum sensing is a critical component of CR as it is a fundamental requirement that a cognitive user (CU) continuously senses the channel before accessing it to avoid causing interference to the primary user (PU) and other radio systems. Due to its low transmit power, detection of PU in a fading environment for an Ultra Wideband (UWB) system is a key problem. This paper presents preliminary works in determining the appropriate sensing period for the cognitive UWB that support multimedia delivery. Firstly, the proposed cross-layer design for multimedia transmission is presented. Next, simulations of bit-error-rate (BER), packet-error-rate (PER) and job-failure-rate (JFR) were carried out to determine the optimal signal-to-ratio (SNR) range to meet the Quality-of-Service (QoS) requirement set for video application. Lastly, the performance of probability of detection against SNR is studied to estimate the appropriate time slot allocation for sensing scheduling.

Inter-cell interference mitigation and coordination in CoMP systems

Coordinated Multi-Point (CoMP) transmission and reception is seen as a promising technology to achieve higher spectral efficiency in LTE-Advanced systems. Base stations cooperation can be one of the most important enabling technologies beneficial in scenarios with high inter-cell interference (ICI). In this paper, interference mitigation and coordination schemes in CoMP are being discussed. Simulation study to show the significant effect of ICI to cell-edge performance is presented. In this work, we proposed an interference cancellation scheme with minimal backhaul requirements in addition to existing inter-cell interference coordination (ICIC) schemes.