In this contribution, we give an overview of the sensitivity of a number of multicarrier systems to carrier and symbol synchronization errors. A comparison is made between orthogonal frequency-division multiplexing/multiple access (OFDM(A)) and two combinations of the orthogonal multicarrier (MC) transmission technique with the code-division multiple access technique (CDMA), i.e. multicarrier C...

The Personal Access Satellite System (PASS) strawman design, as described in the PASS Concept Study Report, (hereafter referred to as the Strawman Design) utilizes a hybrid Time Division Multiple Access (TDMA)/ Frequency Division Multiple Access (FDMA) implementation. TDMA is used for the forward direction (from Suppliers to Users), and FDMA for the return direction (from Users to Suppliers). I...

The Personal Access Satellite System (PASS) strawman design, as described in the PASS Concept Study Report, (hereafter referred to as the Strawman Design) utilizes a hybrid Time Division Multiple Access (TDMA)/ Frequency Division Multiple Access (FDMA) implementation. TDMA is used for the forward direction (from Suppliers to Users), and FDMA for the return direction (from Users to Suppliers). I...

1 Faculty of Electronics and Telecommunications, Communications Dept. Bd. V. Parvan 2, 300223 Timisoara, Romania, e-mail [email protected] Abstract – The main purpose of this paper is to introduce a blind channel estimation technique based on denoising for multiple access schemes in 3GPP Long Term Evolution (LTE) technology, which uses Orthogonal Frequency Division Multiple Access (OFD...

The Long term Evolution (LTE) Uses Orthogonal Frequency Division Multiple Access (OFDMA) in the downlink and Single Carrier Frequency Division Multiple Access (SCFDMA) in the uplink. This paper introduces the transceiver of OFDMA and SCFDMA, discusses difference between the OFDMA and SCFDMA, and highlight the factor that leverages the performance of both multiple access technique, the graphical...

In this paper I intend to present the concept of superframes and its use, primarily, in multiplexing techniques. The signals are supposed band limited and three multiplexing schemes are considered: Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA) and Frequency Hoping Multiple Access (FHMA). The rst two schemes give rise to tight superframes, whereas for FHMA, the ...

AbstractPeak to Average power ratio is the problem being faced in multicarrier system, for Long term evolution(LTE) research is being done for a kind of system that is having lesser PAPR. Single carrier Frequency division multiple access (SC-FDMA) and Orthogonal frequency division multiple access (OFDMA) are major part of LTE. OFDMA was well utilized for achieving high spectral efficiency in co...

This paper presents a new model for systems beyond 3G of cellular communication techniques. The proposed scheme includes several new techniques: multiple-input multiple-output (MIMO), orthogonal frequency division multiplexing (OFDM), and smart antennas (beamforming). The performance analysis was done in an interference-rich environment, and closed form expression for SINR was also determined. ...

In 1993 some hybrid technics combining OFDM and code division multiple access (CDMA) were proposed [3]. One of that technics is multicarrier code division multiple access (MCCDMA) witch introduce frequency spreading and multiple access. Both, OFDM and MCCDMA, have disadvantage in high peak to average power ratio (PAPR). There are many PAPR reduction schemes are for OFDM and most of them is usef...

The use of Code Division for Multiple Access or CDMA is well established. We know that it has advantages in multipath environment and increase in capacity due to sectoring antenna and voice activity factor. Here a step by step comparison is made among Frequency Division Multiple Access, Time Division Multiple Access and Code Division Multiple Access when capacity or SNR is of main concern. A de...