In pervasive and mobile computing environments, “timely and reliable” access to public data requires methods that allow quick, efficient, and low-power access to information to overcome technological limitations of wireless communication and access devices. Literature suggests broadcasting (one-way communication) as an effective way to disseminate the public data to mobile devices. Within the s...

We examine channel access algorithms and circuits for intra and inter chip communication channels. Classical access techniques such as arbitration, scanning, ALOHA, and priority encoding are compared by assessing throughput, latency, and power consumption. Our results provide guidance in the design of bio-inspired networks of processors, for efficient transmission of information with limited po...

Direct sequence code division multiple access (DS-CDMA) communication systems using random polyphase sequences with coherent reception in multipath fading channels are considered. By examining the asymptotic characteristics of the multiple access interference and multipath interference, we show that the DS-CDMA system performance with random mp-phase sequences of mp 3 is better than that with r...

We consider the system access problem for CDMA networks where the access channels are nonorthogonal to the traffic channels. In such systems, the accessing user can degrade the performance of existing users by introducing extra interference. We study how transmit power should be varied with each successive access attempt so that the linear combination of average power expended and the average d...

the present study is aimed at investigating the factors which influence cooperative managers’ awareness of the cooperative sector. methodologically, this is a descriptive-correlated survey. the study consisted of 498 managers of agricultural cooperatives in tehran(n=498), from among whom 72 were selected through random sampling (n=72). validity of the questionnaire used for collecting data was ...

Vehicular ad hoc networks (VANETs) are being designed to improve traffic safety and efficiency. Then it communicates with each other using sensed available spare spectra. In a VANET network, a medium access control (MAC) layer configuration determines a common set of channels to facilitate communication among participating nodes. Because spare spectra change dynamically according to time and lo...

Communication over channels that may vary in an arbitrary and unknown manner from channel use to channel use is studied. Such channels fall in the framework of arbitrarily varying channels (AVCs), for which it has been shown that the classical deterministic approaches with pre-specified encoder and decoder fail if the AVC is symmetrizable. However, more sophisticated strategies such as common r...