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Cognitive Radio (CR) emerges as a promising solution to current unbalanced spectrum utilization. The cognitive ad hoc network can take advantage of dynamic spectrum access and spectrum diversity over wide spectrum. It could achieve higher network capacity compared to traditional ad hoc networks, thus supporting bandwidth-demanding applications. A cognitive(More)
Considering a disk of unit area with n nodes, we investigate the capacity of wireless networks using directional antennas. First, we study the throughput capacity of random directional networks with multihop relay schemes, and find that the capacity gain compared to random omnidirectional networks is O(log n), which is tighter than previous results. We also(More)
Although capacity has been extensively studied in wireless networks, most of the results are for homogeneous wireless networks where all nodes are assumed identical. In this paper, we investigate the capacity of heterogeneous wireless networks with general network settings. Specifically, we consider a dense network with n normal nodes and m = n^b (0(More)
An optical network is too costly to act as a broadband access network. On the other hand, a pure wireless ad hoc network with n nodes and total bandwidth of W bits per second cannot provide satisfactory broadband services since the pernode throughput diminishes as the number of users goes large. In this paper, we propose a hybrid wireless network, which is(More)
Considering the constraints brought by mobility and resources, it is important for routing protocols to efficiently deliver data in intermittently connected mobile networks. Different from previous works that use the knowledge of previous encounters to predict future contacts, we propose a storage-friendly region-based protocol, i.e., RENA, in this paper.(More)
Transmission power control (TPC) has been extensively used not only to save energy, but also to improve the network throughput in wireless ad hoc networks. Among the existing throughput-oriented TPC protocols, many can achieve significant throughput improvement but have to use multiple channels and/or multiple transceivers, and others just require a single(More)
Macrophages are considered of central importance in cell-to-cell transmission of human immunodeficiency virus (HIV) infection in vivo. In this report, we describe a novel cell-to-cell transmission model using HIV-infected monocyte-derived macrophages (MDMs) as donor cells and peripheral blood lymphocytes (PBLs) as recipients. Virus was transmitted during a(More)
Throughput capacity in mobile ad hoc networks has been studied extensively under many different mobility models. However, most previous research assumes global mobility, and the results show that a constant per-node throughput can be achieved at the cost of very high delay. Thus, we are having a very big gap here, i.e., either low throughput and low delay(More)
In this study, we have characterized the HIV DNA-containing replication complexes present in cells early after cell-to-cell infection, using sucrose gradient sedimentation and immunoprecipitation. Six hours after cell-to-cell infection, a cytoplasmic HIV replication complex sedimented as a large structure (320S). This replication complex was precipitated by(More)
Using directional antennas in ad hoc networks may introduce the well-known deafness problem, exacerbate the hidden terminal problem and the exposed terminal problem, add difficulty on mobile communication, and distort the operation of existing routing and TCP protocols. Although a lot of studies have been undertaken on the directional MAC protocols, most of(More)