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This paper proposes a vertical beamforming scheme for fractional frequency reuse to reduce the effect of inter-cell interference in cellular networks. The proposed concept is validated through computer simulation in terms of SINR. SINR of the system when utilizing horizontal and vertical beamforming is compared to confirm that vertical beamforming provides higher SINR to the system. In this paper,...
In this paper, we introduce an orthogonalization aided distributed scheduling algorithm for multiuser MIMO broadcast channels (MU-MIMO BC). In this algorithm each mobile station (MS) selects transmission scheme, including beamforming (BF) and spatial multiplexing (SM) according to its channel state and feeds back channel state information (CSI) adaptively. On receiving CSI from each MS, the base station...
A cognitive radio (CR) network is a secondary network operating in the frequency band and geographical area of a primary network to which the spectrum is licensed. In this paper, we consider a primary broadcasting network consisting of a transmitter and a number of primary users (PUs). The secondary users (SUs) make opportunistic unlicensed spectrum access to communicate with their base station (BS)...
In recent years, smart antenna technologies are of ever-increasing interest to boost the capacity of existing and future wireless systems. Several standards support these techniques such as the wireless metropolitan area network IEEE 802.16 (WiMAX) and IMT-Advanced candidates. In applying smart antenna beamforming and Space Division Multiple Access (SDMA) techniques, adaptive antennas are able to...
In this paper, a novel transmission technique for the multiple-input multiple-output (MIMO) broadcasting directional channels is introduced. During the training period, the base station sends a set of mutually orthogonal signals which enables each user to estimate the angle-of-departure of the anticipated strongest beam and the corresponding SNR. Then, the base station uses the reported angles-of-departure...
Recent work on wireless beamforming has focused on multiuser diversity effects, where terminals in a cellular system are chosen opportunistically from a pool of terminals based on their responses to test beams. Orthogonality between the test beams is typically chosen to aid subsequent interference-free transmission to the corresponding terminals. However, much of this work assumes that i) the pool...
The next generation of wireless networks (e.g.,) will use multiple techniques to improve channel spectral efficiencies. In this paper we focus on one such technique, beamforming, in the downlink channel. In each sector a number of fixed beams are used to serve users. For each frame the scheduler chooses a beam and then schedules one or more mobiles that lie within that beam. Since the basestation's...
In this paper, we consider a multiuser relay network under amplify and forward (AF) scheme, where each mobile station (MS) is supported by a unique relay station (RS). While the RSs forwards the scaled signal to the MSs, the interference caused by the multiuser nature of the system propagates via the RSs, which significantly degrades the performance gain of the relay technique. We propose two beamforming...
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