232 research outputs found
Analysis and Simulation of LTE Downlink and Uplink Transceiver
LTE (Long Term Evolution) is a next generation
standard by 3rd Generation Partnership Project (3GPPP)
consortium. In this paper, the physical layer (PHY) of LTE
transceiver is analyzed in downlink and uplink transmissions.
Simulations of the physical layer of LTE transceiver are
obtained with the use of LTE System Toolbox by Mathworks.
Simulation results are presented to show the performance of
LTE transceivers in Physical Downlink Shared Channel
(PDSCH) and Physical Uplink Shared Channel (PUSCH).
Measurements of throughput and Bit Error Rate (BER) are
obtained for different simulation configurations
A Framework Design for the Next-Generation Radio Access System
Extensive use of the Internet and huge demands for multimedia services via portable devices require the development of packet-based radio access systems with high transmission efficiency. Advanced radio transmission technologies have recently
been proposed to achieve this challenging task. However, few researches have been reported on the design of an integrated system that can efficiently exploit the advantages of these transmission
technologies. This paper considers the design of a packet-based cellular system for next-generation radio access. We propose a novel system framework that can incorporate various advanced transmission technologies such as link adaptation, opportunistic packet
scheduling, channel coding, and multiantenna techniques. For efficient use of these technologies together, we first investigate the interoperability between these technologies by proposing a so-called
cause and effect analysis. Based on this investigation, we design a differentiated-segments-based orthogonal frequency-division multiplexing system, called DiffSeg, to accommodate heterogeneous operating conditions in a seamless manner. Simulation results show that the proposed DiffSeg system can provide a nearly optimum
performance with flexible configuration in a wide range of wireless channel conditions
Optimisation of relay placement in wireless butterfly networks
As a typical model of multicast network, wireless butterfly networks (WBNs) have been studied for modelling the scenario when two source nodes wish to convey data to two destination nodes via an intermediary node namely relay node. In the context of wireless communications, when receiving two data packets from the two source nodes, the relay node can employ either physical-layer network coding or analogue network coding on the combined packet prior to forwarding to the two destination nodes. Evaluating the energy efficiency of these combination approaches, energy-delay trade-off (EDT) is worth to be investigated and the relay placement should be taken into account in the practical network design. This chapter will first investigate the EDT of network coding in the WBNs. Based on the derived EDT, algorithms that optimize the relay position will be developed to either minimize the transmission delay or minimize the energy consumption subject to constraints on power allocation and location of nodes. Furthermore, considering an extended model of the WBN, the relay placement will be studied for a general wireless multicast network with multiple source, relay and destination nodes
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