This paper proposes a numerical method for characterizing the achievable rate region for a Gaussian multiple access channel with ISI under the frequency division multiple access restriction. The frequency spectrum is divided into discrete frequency bins and the discrete bin assignment problem is shown to have a convex programming relaxation, making it tractable to numerical algorithms. The run-...

This paper deals with spreading sequences selection for downlink and uplink Multi-Carrier Code Division Multiple Access (MC-CDMA) systems with the aim of minimizing the dynamic range of the transmitted multicarrier signal envelope and the multiple access interference. The crest factor of orthogonal and non-orthogonal sequences are compared analytically and by simulation for downlink and uplink ...

Abstract Multi-carrier direct sequence code division multiple access (MC DS-CDMA) is a combination of time-domain spreading and orthogonal frequency division multiplexing (OFDM), while multi-carrier code division multiple access (MC-CDMA) is a combination of frequency-domain spreading and OFDM. In MC-CDMA, a good bit error rate (BER) performance can be achieved by using frequency-domain equaliz...

This paper deals with channel estimation, and detection in ultra wide band (UWB) bi-phase impulse modulated systems. We address the single user and the multiuser scenario assuming a direct sequence spreading code division multiple access (DS-CDMA) scheme. The channel estimation and detection approach is single user based, and operates in the frequency domain. In the presence of multiple access ...

This paper provides a review on the orthogonal frequency division multiplexing (OFDM) and interleave division multiple access (IDMA) by using AWGN and Rayleigh fading channel. OFDM-IDMA is a composite communication system. This system has been receiving significant research attention due to their capability to address the problem like inter symbol interference (ISI) and multiple access interfer...

Vehicle-to-vehicle radio links suffer from multipath fading and interference from other vehicles. We discuss the impact of these effects on communication networks supporting an intelligent transportation system (ITS), in particular, automated vehicle control systems (AVCS’s). A statistical model for this channel is considered, and the performance of the network involving many links is evaluated...

This paper is concerned with multi-user detection techniques for orthogonal frequency division multiplexing – interleave division multiple access (OFDM-IDMA) and IDMA with cyclic prefix (IDMACP). These two schemes have attractive features such as low-cost multi-user detection/equalization and flexible rate adaptation. We will show that significant performance improvement (i.e., the so-called mu...

Multiple users TDS-OFDMA has been proposed based on time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM). This multiple access schemes used mostly in mobile broadband wireless access scheme in uplink transmission due to the multiple user interference in timing offset and frequency offset problems. In this paper we are focusing on timing synchronization and channel estim...

The spectral efficiency of a multicarrier direct-sequence code-division multiple-access (MC/DS-CDMA) cellular system operating in a mobile radio environment with Rayleigh fading, is investigated. In this work, spectral efficiency is evaluated in terms of channel capacity (in the Shannon sense) per user, estimated in an average sense. It is analytically shown that, under normalized conditions an...

We propose a Mutual Information (MI) based spatial frequency domain packet scheduling algorithm for uplink Orthogonal Frequency Division Multiple Access (OFDMA) multiuser multiple-input, multiple-output (MIMO) systems in this paper. The proposed scheduler is designed particularly for signal constellation constrained MIMO systems. The superiority of the investigated scheduler coupled with the in...