in this paper first we try to analysis the behavior ofthe soas in the optical networks and then have proposed anumerical simple model to simulate the behavior of thesemiconductor optical amplifiers. after that by employing thismodel as inline amplifier for a dwdm optical system, we havesimulated the transmission of 10 channels with bit rate 10 gb/sup to distance 3970 km with rz-dpsk modulation ...

Orthogonal frequency division multiplexing (OFDM) is a suitable candidate for broadband power line communications (PLC). It has shown that the Bit Error Rate (BER) performance of Single Carrier Transmission with Frequency Domain Equalization (SCT-FDE) is close to OFDM in broadband wireless systems. In this paper we investigate the BER performance of SCT employing time and frequency domain decis...

Orthogonal frequency division multiplexing (OFDM) is particularly divided to three varieties. Cyclic prefix OFDM, zero padding OFDM, and time domain synchronous OFDM. Compared to CP OFDM, TDS-OFDM has higher spectral efficiency and faster synchronization. This paper reviewed however efficiently uses the compressive sensing (CS) theory to resolve those problems. During this paper, a noise cancel...

Abstract: Orthogonal frequency division multiplexing (OFDM) combined with time division multiplexing (TDM) can bridge the conventional OFDM and single carrier (SC) transmission by using minimum mean square error (MMSE) frequencydomain equalization (FDE). The channel frequency-selectivity can be exploited by MMSE-FDE to improve the bit error rate (BER) performance. A much better BER performance ...

To meet the exploding demand for Internet and broad-band services, dense wavelength-division-multiplexing systems have been extended from long-haul transmission systems to metropolitan and access area networks. In such systems, compact and conventional arrayed-waveguide grating multi/demultiplexers are required to reduce the cost of the systems. The evolution of broadband services will depend o...

Abstract: In this paper, a theoretical BER analysis of orthogonal frequency division multiplexing combined with time division multiplexing (OFDM/TDM) is presented for joint use of space-time transmit diversity (STTD) and receive antenna diversity with minimum mean square error (MMSE) frequency-domain equalization (FDE). The conditional BER expression is derived, based on a Gaussian approximatio...

We propose Joint Spatial Division and Multiplexing (JSDM), an approach to multiuser MIMO downlink that exploits the structure of the correlation of the channel vectors in order to allow for a large number of antennas at the base station while requiring reduced-dimensional Channel State Information at the Transmitter (CSIT). This allows for significant savings both in the downlink training and i...

Multiple users can be served by the same bandwidth in wireless CDMA systems of spread spectrum. The use can used the bandwidth and different codes at the same time and any signal showed by one of the user is seen as interference. This interference is detected to the base station in the process of extracting data used by a specific signal utilized by a user. Users who are closer to the BS are th...

Multiple users can be served by the same bandwidth in wireless CDMA systems of spread spectrum. The use can used the bandwidth and different codes at the same time and any signal showed by one of the user is seen as interference. This interference is detected to the base station in the process of extracting data used by a specific signal utilized by a user. Users who are closer to the BS are th...