A novel mathematical method is presented to express the outage probability for a desired radio signal received from a mobile transmitter in the presence of multiple interfering signals with combined lognormal and Rayleigh fading. In contrast to previously reported analysis, this exact method avoids approximation of the pdf of the received powers of the various signals. This is useful in determi...

Spatial reuse TDMA is an access scheme for multi-hop radio networks. The idea is to increase capacity by letting several radio terminals use the same time slot when possible. A time slot can be shared when the radio units are geographically separated such that small interference is obtained. STDMA schedules can assign transmission rights to nodes or alternatively assign transmission rights to l...

Interference and delay are considered as the major reasons limiting the capacity and increasing the new call blocking probability in cellular system. In this paper we introduce a novel strategy based on cognitive radio. Cognitive radio is defined as a radio or system that senses its environment and can dynamically and autonomously change its transmitter parameters based on interaction with the ...

The radio waves are more complex in confined environments. In order to obtain the propagation character of radio wave in the mine tunnel, the electric-field intensity and magnetic-field intensity of horizontal polarization wave are deduced according to Maxwell equation and the boundary condition of tunnel. The attenuation coefficients of electric field in horizontal and vertical polarization ar...

Wireless networks are founded on the principles of collision avoidance. This paper makes an attempt to detect and abort collisions in wireless networks. Briefly, the receiver uses physical layer information to detect collisions, and immediately notifies the transmitter to abort transmission. The collision notification consists of a unique signature, sent on the same frequency channel as the dat...

The subject of secondary spectrum usage has been a hot research topic for some time now. Secondary users should be able to detect available primary frequency bands and use these spectrum opportunities without causing any harmful interference to primary users. The aim of this paper is to propose a new methodology, based on image processing techniques, which combines a number of sensed samples at...

– Adaptive transmission techniques such as adaptive modulation and transmitter antenna diversity have been proposed for mobile wireless systems to satisfy high data-rate service requirements. In rapidly time variant channels, these methods need the knowledge of future fading conditions and therefore require accurate long range fading prediction. We investigate three combined adaptive modulation...

Cognitive radio is being intensively researched for opportunistic access to the so-called TVWhite Spaces (TVWS): large portions of the VHF/UHFTVbandswhich become available on a geographical basis after the digital switchover. In this paper we take a step back from the excitement surrounding TVWS, and quantitatively examine the real spectrum opportunity associated with this form of access. Using...

Along with rapid development of sensing and communication technology, Internet of Things (IoTs) has enabled a tremendous number of applications in health care, agriculture, and industry. As the fundamental element, the wireless sensing node, such as radio tags need to be operating under micro power level (e.g, 100 μW, Pico radio) for energy autonomy. The evolution of electronics towards highly ...

Emerging distributed wireless microsensor networks will enable the reliable and fault tolerant monitoring of the environment. Microsensors are required to operate for years from a small energy source while maintaining a reliable communication link to the base station. In order to reduce the energy consumption of the sensor network, two aspects of the system design hierarchy are explored: design...