Driven by the significant consumer demand for reliable and high data rate communications, the future-generation cellular systems are expected to employ cutting-edge techniques to improve the service provisioning at substantially reduced costs. Cooperative relaying is one of the primary techniques due to its ability to improve the spectrum utilization by taking advantage of the broadcast nature ...

nowadays, wireless sensor network has been of interest to investigators and the greatest challenge in this part is the limited energy of sensors. sensors usually are in the harsh environments and transit in these environments is hard and impossible and moreover the nodes use non- replaceable batteries. because of this, saving energy is very important. in this paper we tried to decrease hard and...

in this paper, an algorithm , based on genetics and auxiliary nodes, to reduce energy consumption in wireless sensor networks has been presented. in this research, by considering some parameters as energy and distance, a target function has been created, which is more optimum comparing to other methods. in this research cluster head is selected by genetic algorithm. in rawsn algorithm a new tec...

Vectored Multiple Access Channels (MAC) have attracted a lot of interest during the past few years. The optimal structure of vectored MAC in the uplink is based on the Successive Interference Canceller-Minimum Mean Square Error (SIC-MMSE). For equal weights and zero Signal to Noise Ratio (SNR) gap, the optimal transmit covariance matrices are found by iterative waterfilling. However, practical ...

one of the main challenges in wireless sensor network is energy problem and life cycle of nodes in networks. several methods can be used for increasing life cycle of nodes. one of these methods is load balancing in nodes while transmitting data from source to destination. directed diffusion algorithm is one of declared methods in wireless sensor networks which is data-oriented algorithm. direct...

ieee 802.11e standard is proposed to support quality of service (qos) in wireless local area networks (wlans). the distributed access method of 802.11e, enhanced distributed channel access (edca), prioritizes traffic generated by delay-sensitive applications by increasing probability to access medium for this type of traffic. edca resets the contention window (cw) of mobile stations to a minimu...

A Detailed Exploration of usability statistics and Application Rating on short-range Wireless protocols Bluetooth (IEEE 802.15.1), ZigBee (IEEE 802.15.4), Wi-Fi (IEEE 802.11) and NFC (ISO/IEC 14443) has been performed that being representing of those prominent wireless protocols evaluating their main characteristics and performances in terms of some metric such as co-existence, data rate, secur...

This paper reviews recent work on spread spectrum network capacity. The network is shown to have a capacity that is equitably shared amongst the users via power control. This solution is much simpler than the bandwidth partitioning of the FDMA/reuse approach. The capacity gains from using spread spectrum, arising from the averaging and multiplexing, are also emphasised.