Moreover, the two-dimensional (2-D) spreading codes, spreading on both time and frequency domain, has been applied to OFDM system [5-6]. Using the orthogonality property between the 2-D codes, the orthogonal frequency coded division multiplexing (OFCDM) is performed in the downlink for mobile communication systems [7-8]. The diversity gain can be obtained from frequency domain or time domain, r...

In this project, I have studied the performance gain of MIMO systems. There are two types of gain provided by the MIMO channels: one measures the increase of the capacity by the number of degrees of freedom of the channel (spatial multiplexing gain), and the other improvement of the reliability by the diversity gain. Most of previous works focus on either one of these two types of gain by desig...

In the IEEE 802.11a WLAN standard, orthogonal frequency division multiplexing (OFDM) modulation is employed. Diversity techniques are effective way to overcome multipath fading in the OFDM systems. A fractional sampling (FS) scheme is one of the diversity techniques with a single antenna. Through FS it is possible to separate multipath components and obtain diversity gain in OFDM. Though FS has...

The diversity is used to provide the receiver with several replicas of the same signal. The diversity techniques like selection diversity, equal gain diversity and maximum ratio combining diversity have been discussed to improve the quality of service parameters in CDMA communication network. Key WordsQos, Network, Diversity, CDMA, Gain * Computer Science Department, MGM College of Engineering&...

We analyse the spatial diversity of a multipath fading process for a general geometrical base of a dense antenna array in the plane and characterise it by the eigenvalue spectrum of the spatial autocorrelation kernel. We show how this diversity spectrum can be calculated for any spatial fading statistics represented by the power azimuth spectrum (PAS). Numerically calculated diversity spectra h...

This paper considers transmit diversity schemes applied to cross-polarized linear antennas at cellular basestations, with a single linearly polarized antenna used by the mobile station receiver. The performance of SpaceTime Block Code (STBC) and Time-Delay Transmit Diversity (TDTD) is analyzed as a function of the relative orientation of the transmit and receive antennas. It is shown that power...

Wireless communication demands high data rates with great quality and accuracy but such requirements can only be achieved if the signal could be received without being affected by the channel impairments. In these entire impairments multipath fading is the major problem in achieving reliable wireless transmission. It is due to the combination of constructive and destructive multipath signals re...

-Single-Carrier Frequency Domain Equalizer (SCFDE) scheme has several advantages than multi-carrier scheme OFDM. SC-FDE avoids all the drawbacks of OFDM. This paper analyzes the diversity gain of multi-input-multi-output (MIMO) SCFDE in frequency selective channels. This paper fully analyzes the Alamouti signaling scheme under linear equalizers such as Zeroforcing (ZF) and MMSE equalizers. The ...

In Part I of this two-part paper, we described the effective gain characteristics of the handset diversity antenna comprising a retractable whip antenna and a built-in planar inverted F antenna (PIFA). In order to achieve a high diversity effect, the correlation between the diversity branches must be small while at the same time maintaining a high effective gain, and this is contained in this p...

Multi-hop relay channels use multiple relay stages, each with multiple relay nodes, to facilitate communication between a source and destination. Previously, distributed space-time codes were proposed to maximize the achievable diversity-multiplexing tradeoff, however, they fail to achieve all the points of the optimal diversitymultiplexing tradeoff. In the presence of a low-rate feedback link ...