In this paper, a network-centric subcarrier allocation method is proposed for triple-sectored Orthogonal Frequency Division Multiple Access (OFDMA) systems. The proposed method is based on a networkcentric algorithm that is located in a base station (BS) and coordinates the subchannel allocation of each sector. This method controls the resources (subchannels) allocated to each sector, not to wa...

We study four-wave mixing between pulses in two subchannels of a quasi-linear 40-Gbit/s subchannel-multiplexed system. For a pseudorandom bit string there are resonances in the mean of the ghost pulse energy and in the jitter of the energy in the marks as functions of the subchannel frequency spacing. However, away from these resonances the effect of four-wave mixing decreases as the subchannel...

This paper investigates the problem of dynamic multiuser subchannel allocation in the downlink OFDM systems. In traditional TDMA or FDMA systems, resource allocation for each user is non-adaptively fixed. Since the subchannel allocations among the users are not optimized, a group of users is likely to suffer from poor channel gains resulting from large path loss and random fading. To resolve th...

Femtocells have attracted growing attention in academia, industry, and standardization forums in recent years. However, most of existing works on femtocell networks are focused on spectrum efficiency and interference mitigation, energy efficiency aspect is neglected. In this paper, we investigate the energy efficient resource allocation of downlink femtocell networks in sparsely and densely dep...

We consider an orthogonal frequency division multiple access (OFDMA)-based multicast system where multiple base stations transmit a multicast session to a multicast group. The goal is to maximize the multicast rate (i.e. the minimum achievable user rate) subject to a total power constraint. We assume the use of an erasure code (e.g., a Reed–Solomon code) or rateless code (e.g., Luby transform c...

We focus on the channel estimation and the decoding of orthogonal frequency-division multiplexing (OFDM) signals in networking scenarios with multipath propagation and strong cochannel interference (CCI). The receiver views the CCI contained in the subchannel signal observations as additional independent Gaussian noise terms with varying variance from subchannel to subchannel as a consequence o...

The Filtered Multitone (FMT) modulation requires both equalization of the transmission channel and of the transmit subchannel filters. Since decision feedback equalization is affected by error propagation and yields a greater complexity when combined with coding, in this paper we consider the use of pre-coding for FMT. However, by observing that precoding disrupts partially the subchannel ortho...

The performance of DMT systems is studied in impulsive noise channels by using Middleton's Class A noise distribution. A statistical model is developed to generate Class A distributed impulsive noise samples and this model is used for the performance analysis. An exact expression is derived for the subchannel SER. By employing the central limit theorem, the subchannel SER is further simplified....

This letter investigates a subchannel and power allocation (SPA) algorithm which maximizes the throughput of a user under the constraints of total transmit power and fair subchannel occupation among relay nodes. The proposed algorithm reduces computational complexity from exponential to linear in the number of subchannels at the expense of a small performance loss. key words: OFDMA, cooperative...

In order to improve the throughput performance of Medium Access Control (MAC) schemes in wireless communication networks, some researchers proposed to split the single shared channel into two subchannels: a control subchannel and a data subchannel. The control subchannel is used for access reservation to the data subchannel over which the data packets are transmitted, and such reservation can b...