We propose an optimum channel shortening method for discrete multitone (DMT) transceivers. The proposed method shortens a given channel to a desired length while maximizing the number of bits transmitted on a DMT symbol. The key to the optimum solution is the de nition of the SNR in a subchannel using the equivalent signal, noise, and ISI paths in the system. Our simulation results show that th...

In this paper, we study the problem of resource allocation for a multiuser orthogonal frequency-division multiple access (OFDMA) downlink with eavesdropping. The considered setup consists of a base station, several users and a single eavesdropper that intends to wiretap the transmitted message within each OFDMA subchannel. By taking into consideration the existence of the eavesdropper, the base...

In this article, the problem of downlink subcarrier allocation in a cooperative wireless multiuser OFDM system is investigated. We consider a single-cell where all the users are paired in cooperative groups. The mobile users in each group amplify and forward their partner’s data stream using a time division protocol. Based on the capacity contribution from the relaying terminal, a new parameter...

Vehicle to many vehicles (V2MV) multicast is an attractive application to provide vehicle safety and traffic control information, urban sensing and multimedia content sharing in vehicular ad hoc networks. Due to the limitation of DSRC channels, Wi-Fi channels can be alternative to realize the multicast in the vehicular networks. However, the deployment using the Wi-Fi in ISM bands is challengin...

A key feature of the packet scheduler in LTE system is that it can allocate resources both in the time and frequency domain. Furthermore, the scheduler is acquainted with channel state information periodically reported by user equipments either in an aggregate form for the whole downlink channel, or distinguished for each available subchannel. This mechanism allows for wide discretion in resour...

For any channel $P_{Y|X}$ the strong data processing constant is defined as smallest number notation="LaTeX">$\eta _{KL}\in [{0,1}]$ such that notation="LaTeX">$I(U;Y)\le \eta _{KL} I(U;X)$ holds for Markov chain notation="LaTeX">$U-X-Y$ . It shown value of _{KL}$ given by best binary-input subc...

In this paper, we consider a single-cell multi-user orthogonal frequency division multiple access (OFDMA) network with one unmanned aerial vehicle (UAV), which works as an amplify-and-forward relay to improve the quality-of-service (QoS) of user equipments (UEs) in cell edge. Aiming throughput while guaranteeing fairness, jointly optimize communication mode, subchannel allocation, power and UAV...

Abslmct-In Alamouti coded O F D M systems, the simple decoding at the receiver relies on the assumption that the subchannels are flat fading, decoupled, and quasi-static so that each subchannel does not change over an Alamouti codeword period (two consecutive OFDM symbol periods). When the channel is fast fading, however, these assumptions are not met, resulting in severe performance degradatio...

Today, we have required to accommodate a large number of users under a single base station. This can be possible only if we have some flexibility over the spectrum. Previously we have lots of multiplexing methods to accommodate large number of signals in time and frequency domain. But now we have required to accommodate a large number of users in the same bandwidth, without any fading over the ...