Babak Hossein Khalaj

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Orthogonal frequency-division multiplexing (OFDM) introduces large amplitude variations in time, which can result in significant signal distortion in the presence of nonlinear amplifiers. In this paper, we introduce a new bound for the peak of the continuous envelope of an OFDM signal, based on the maximum of its corresponding oversampled sequence, that is(More)
In this paper, we consider multiple cache-enabled clients connected to multiple servers through an intermediate network. We design several topology-aware coding strategies for such networks. Based on the topology richness of the intermediate network, and types of coding operations at internal nodes, we define three classes of networks, namely, dedicated,(More)
.lhsiroc,In this papcr. I ne\, achcmc fur adaptive ruhcarricr. hi1 iled prrwer allnc;ition fbr downlink tmnsmission of multiuser orthogon;!l fiequcncy division multiplesing (0I;DhI) systcms i s prrscnted. I n adaptive algorithm is introduced to achieve the t ics i re t i hit ralc and BER for QoS (quality niservicc) of different LIUTS in it frequency(More)
In this paper, the goal is to propose an optimal handoff algorithm for hybrid networks (HNs), which are constructed by interworking between wireless LANs (WLANs) and mobile networks. The proposed algorithm is an adaptive fuzzy logic based algorithm that can adapt itself with the dynamic conditions in HNs. It uses mobile terminal speed estimation and traffic(More)
A technique is proposed for estimating the parameters of two-dimensional (2-D) uniform motion of multiple moving objects in a scene, based on long-sequence image processing and the application of a multiline fitting algorithm. Plots of the vertical and horizontal projections versus frame number give new images in which uniformly moving objects are(More)
In this paper, we introduce a new cost function for SIR-Based uplink power control algorithms that takes into account transmission power level as well as target Signal-to-Interference Ratio (SIR) deviation. Existence of Nash equilibrium point, its uniqueness and the algorithm convergence are proved in the framework of so-called standard power control(More)
Mobile radio channels can be generally characterized as a fading multipath channel with multipath spread delay that ranges from a few microseconds (11s) up to as much as 15 ps . Such large delays result in intersymbol interference which raises the need for equalization. In this paper, a semi-blind maximum likelihood sequence estimation (MLSE) with antenna(More)
In this paper, we consider the problem of optimum selection of quality-of-service (QoS) classes in interworking between the networks in a next-generation-network (NGN) environment. After introducing the delay-cost and loss-cost characteristics, we discuss the time-invariant (TI) and time-variant (TV) scenarios. For the TI case, we show that under nearly(More)
In this paper, we consider a cellular cognitive radio network that adopts opportunistic spectrum access for its data transmission in the downlink from base stations (BSs) toward cognitive radio users (CRs). Since the spectrum is licensed to a primary network, base stations of the cellular secondary network should protect primary users against excessive(More)