in this paper, a new propagation model based on utd for multiple diffraction paths in cellular mobile radio communications in urban environments is proposed. moreover, the most rigorous novel utd-based expressions for multiple diffractions by buildings and excess path losses are d - rived and analyzed. for this purpose, building rows are supposed to have rectangular cross-sections with the same...

a typical radio frequency identification system (rfid) includes one reader and a number of tags. the reader transmit to commands to the tags with interrogation radio signals, and tags receive the command and then respond with their identification. readers with interrogation signals can read tags’ responses. in rfid systems, when multiple tags respond to one reader simultaneously, tag collision ...

Wireless mesh networks (WMNs) which mediates the broadband Internet access, have been recently received many attentions by the researchers. In order to increase capacity in these networks, nodes are equipped with multiple radios tuned on multiple channels emerging multi radio multi-channel WMNs (MRMC WMNs). Therefore, a vital challenge that poses in MRMC WMNs is how to properly assign channels ...

We simulate the evolution of relativistic electrons injected into intracluster medium by five radio galaxies. study spatial transport and emission properties plasma over a ∼5 Gyr period, sequence cooling re-acceleration events experienced electrons, using Lagrangian approach joined with numerical method to model momentum spectra electrons. When compared shock waves, galaxies (here limited singl...

many appealing multicast services such as on-demand tv, teleconference, online games and etc. can benefit from high available bandwidth in multi-radio multi-channel wireless mesh networks. when multiple simultaneous transmissions use a similar channel to transmit data packets, network performance degrades to a large extant. designing a good multicast tree to route data packets could enhance the...

it is shown in [1] that the optimal downlink radio resource allocation for non-realtime traffic in cellular cdma/tdma networks can be mapped to a multi-dimensional multiple-choice knapsack problem (mmkp) which is np-hard. in this correspondence we propose a heuristic algorithm with polynomial time complexity for this problem. numerical results indicate significant computational performance impr...

Many appealing multicast services such as on-demand TV, teleconference, online games and etc. can benefit from high available bandwidth in multi-radio multi-channel wireless mesh networks. When multiple simultaneous transmissions use a similar channel to transmit data packets, network performance degrades to a large extant. Designing a good multicast tree to route data packets could enhance the...

In this demo, we propose to use multiple inexpensive off-the-shelf radios to build the FAIR system that can be flexibly configured to realize (1) non-contiguous spectrum access (2) MIMO and beamforming (3) constructing wider-band radio. While non-contiguous spectrum access and MIMO/beamforming are naturally supported by the FAIR system, we further develop radio bonding technique for constructin...