Current Issue : April - June Volume : 2014 Issue Number : 2 Articles : 4 Articles
An intra-vehicular wireless sensor network is designed and implemented on a software-defined radio system. IUWB signal is\r\nchosen to carry the data packets. The MAC layer of the system follows the specification of the IEEE802.15.4 standard. The\r\ntransceiver design, especially the receiver design, is detailed in the paper. The system design is validated through lab test setup....
Interference coordination methods for Evolved-Multimedia Broadcast/Multicast Service (E-MBMS) in Long-Term Evolution\r\nAdvanced (LTE-A) are presented. In addition, we consider signal space diversity based on Rotation Matrices (RM) known to\r\nprovide good performance gains over uncorrelated Rayleigh fading channels. OFDM/OFDMA systems can make the use of RM\r\nvery attractive both for single andmultiple antenna transmissions. In this paper, OFDM/OFDMA signals based on LTE parameters\r\nare combined with RM, MIMO, Turbo, or LDPC codes.We have considered different types of receivers, namely, we used an MMSE\r\n(Minimum Mean Squared Error) equalizer and a Maximum Likelihood Soft Output criterion (MLSO). Frequency, signal, and\r\nspace diversity gains are evaluated for different spatial channel models (SCM) based on ITU multipath propagation channels.\r\nDifferent adaptive frequency reuse and schedulers are considered to evaluate the E-MBMS spectral efficiency at the cell borders....
High Peak to Average Power Ratio (PAPR) is a critical issue in multicarrier communication systems using Orthogonal Frequency\r\nDivision Multiplexing (OFDM), as in the Second Generation Terrestrial Digital Video Broadcasting (DVB-T2) system. This\r\nproblem can result in large performance degradation due to the nonlinearity of the High Power Amplifier (HPA) or in its low\r\npower efficiency. In this paper, we evaluate the performance of different Tone Reservation-based techniques for PAPR reduction in\r\nDVB-T2 context. Also, we propose an iterative TR-based technique called ââ?¬Å?One Kernel One Peakââ?¬Â (OKOP). Simulation results and\r\nperformance comparison of these techniques in terms of gain in PAPR reduction, mean power variation, and complexity will be\r\ngiven. Finally, we describe the implementation of a PAPR reduction algorithm in the DVB-T2 modulator....
The creation and wide use of new high quality demanding services (VoIP, High Quality Video Streaming) and the delivery of\r\nthem over already saturated core and access network infrastructures have created the necessity for E2E QoS provisioning. Network\r\nProviders use at their infrastructures several kinds of mechanisms and techniques for providing QoS. Most known and widely\r\nused technologies are MPLS and DiffServ. The IEEE 802.16-2004 standard (WiMAX) refers to a promising wireless broadband\r\ntechnology with enhanced QoS support algorithms. This document presents an experimental network infrastructure providing\r\nE2E QoS, using a combination of MPLS and DiffServ technologies in the core network and WiMAX technology as the wireless\r\naccess medium for high priority services (VoIP, High Quality Video Streaming) transmission. The main scope is to map the\r\ntraffic prioritization and classification attributes of the core network to the access network in a way which does not affect the E2E\r\nQoS provisioning. The performance evaluation will be done by introducing different kinds of traffic scenarios in a saturated and\r\noverloaded network environment. The evaluation will prove that this combination made feasible the E2E QoS provisioning while\r\nkeeping the initial constrains as well as the services delivered over a wireless network....
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