Kathiravetpillai Sivanesan

Outage and BER of MRC diversity in bandlimited micro-cellular systems with CCI

Maximal ratio combining for bandlimited BPSK in micro-cellular systems with cochannel interference is considered. A Nakagami/Rayleigh fading model is assumed. Spectrum raised-cosine and Beaulieu-Tan-Damen pulse shapes are employed. Exact closed-form expressions for outage probability with equal and different interferer powers are derived. An average bit error rate approximation is derived using a Gaussian assumption for the cochannel interference. Monte-Carlo simulation is used to validate the Gaussian assumption. The results are valid for arbitrary diversity order and desired user fading parameter. Slow flat fading, asynchronous timing and independent fading gains are assumed.

BER Performance of Bandlimited DS-CDMA Systems in Nakagami Fading

Accurate average bit-error rate analysis of asynchronous bandlimited binary direct-sequence code-division multiple-access (DS-CDMA) systems in Nakagami-m fading is studied. The fading is assumed to be flat and slow. The spectrum raised-cosine (SRC) and Beaulieu-Tan-Damen (BTD) pulse-shapes are employed. A new method which combines the characteristic function (CF) method with the improved Gaussian approximation (GA) is proposed for evaluating the BER of bandlimited DS-CDMA. A substantial computational complexity reduction is achieved. The well-known standard GA, Holtzmans simplified improved GA, and improved Holtzmans GA methods are also considered. The accuracies of the approximation methods are assessed using Monte Carlo simulation. For a system employing a deterministic sequence for the desired user and random sequences for the active interfering users, a CF method is employed to derive precise BER results. The new BTD pulse outperforms the SRC pulse in all situations

Performance analysis of bandlimited DS-CDMA systems in Nakagami fading

Accurate performance analysis of asynchronous bandlimited binary DS-CDMA systems in Nakagami-m fading is considered. The fading is assumed to be flat and slow. The spectrum raised-cosine and Beaulieu-Tan-Damen pulse shapes are employed. A new accurate approximation for computing the bit error rate of bandlimited DS-CDMA systems employing random spreading sequences is proposed. A substantial computational complexity reduction is achieved. The well-known standard Gaussian approximation, Holtzmans simplified improved Gaussian approximation, and the improved Holtzmans Gaussian approximation are also considered. The accuracies of the approximations are assessed using Monte-Carlo simulation. For a system employing a deterministic sequence for the desired user and random sequences for the active interfering users, a characteristic function method is employed to derive exact BER results. The new Beaulieu-Tan-Damen pulse outperforms the spectrum raised-cosine pulse in all situations examined.

Precise Outage Analysis of Selection Diversity and Switched Diversity in Bandlimited Micro-Cellular Systems With Cochannel Interference

Precise outage probability performance analysis of a microcellular system with selection and switched diversities is considered. The microcellular system is assumed to follow a flat, slow Nakagami/Rayleigh fading model wherein the fading channels from the desired transmitter to all the receiver antennas are independent and identically distributed Nakagami channels, and all the fading channels for the interfering signals are independent, identically distributed Rayleigh channels. Three selection and switching criteria, namely, desired signal power, signal-to-interference power ratio, and total output power are considered. Unlike previous results, the system model under investigation takes into account the pulse shaping, the random delays, and the phase offsets of the interfering users. Two Nyquist pulse shapes, spectrum-raised-cosine and Beaulieu-Tan-Damen pulse shapes, are considered. Analytical outage probability expressions are derived for an arbitrary number of interferers, arbitrary diversity order, and arbitrary value of desired user fading parameter. The outage performances of the selection criteria are compared. The optimum switching thresholds for different switching criteria are formulated.

Accurate BER analysis of bandlimited DS-CDMA system with EGC and SC diversity over Nakagami fading channels

Accurate average bit error rate analysis of diversity receivers for asynchronous bandlimited binary DS-CDMA systems operating over Nakagami-m fading channels is studied. Predetection equal gain combining (EGC) and selection combining (SC) are considered. The fading is assumed to be flat and slow, and random spreading sequences are considered. The spectrum raised cosine (SRC) and Beaulieu-Tan-Damen (BTD) pulse shapes are employed. The improved Gaussian approximation for multiple access interference is employed with characteristic function and Fourier series methods for the performance analysis. Our results are valid for arbitrary diversity order and arbitrary Nakagami fading parameter and the computational complexity does not grow with the diversity order. The new Beaulieu-Tan-Damen pulse outperforms the spectrum raised-cosine pulse in all situations examined.

CCI mitigation using interference whitening in bandlimited micro-cellular BPSK systems

Cochannel interference mitigation in bandwidth efficient BPSK systems operating in slow, flat fading microcellular environments is considered. The desired and interfering users undergo Nakagami-m and Rayleigh fading, respectively. A whitening matched filter and fractionally spaced linear minimum mean square error equalizer are employed in the receiver. While whitening maximizes the signal-to-noise-plus-interference ratio, the whitening matched filter introduces intersymbol interference in the decision statistic. A minimum mean square error equalizer is used to combat the intersymbol interference. Important observations regarding the performance of the proposed receiver structure are made. The performance with Beaulieu-Tan-Damen pulse shaping is always better than with spectrum raised-cosine pulse shaping. The performance is considerably better than the conventional matched filter receiver under a variety of fading conditions for the desired user. The performance gain decreases with the severity of the fading of the desired user. When the cochannel interference is synchronous, the performance can approach the optimum single user performance by appropriately choosing the tap spacing and length of the equalizer.

Code Book Based CL-MIMO for DL Wimax Rel. 1.5: System Level Performance Analysis

In this paper, gains of the codebook based CL-MIMO for down link WiMax system has been studied using system level simulations. The system level simulation is based on the IEEE 802.16m evaluation methodology. The 2×2 and 4×2 antenna configurations, and 3 bits and 6 bits preferred matrix index (PMI) feedback codebooks are considered. Both the sub-band and wide band PMI feedback are studied. The results show that the CL-MIMO provides substantial gains in cell edge and average sector throughput over OL-MIMO system.

Interference whitening receivers for CCI mitigation in micro-cellular BPSK systems

Cochannel interference and fading are the dominant impairments in micro-cellular wireless communication systems. Cochannel interference mitigation for BPSK systems in slow, flat fading micro-cellular environments is considered. Nonreturn-to- zero (rectangular) pulse shaping is considerd to allow analytical solutions. Slow Rayleigh faded cochannel interference is Gaus- sian distributed after the demodulation. Thus, a receiver struc- ture which maximizes the instantaneous signal-to-noise plus inter- ference ratio, minimizes the average bit error rate. A whitening matched filter receiver is used instead of a conventional matched filter. While whitening maximizes the signal-to-noise plus inter- ference ratio, it introduces intersymbol interference in the deci- sion statistic. A fractionally spaced minimum mean square error equalizer is employed to combat the intersymbol interference. The performance of the proposed receiver structure closely approaches the optimum single user performance when appropriately chosen tap lengths and tap spacings are employed. An optimal decorre- lating receiver structure that bases its decision on observation over one symbol duration is also proposed. I. INTRODUCTION

Precise performance analysis of MRC diversity in microcellular systems with cochannel interference

The outage and BER analysis of maximal ratio combining for bandlimited BPSK systems in microcellular system with cochannel interference is considered. A Nakagami/Rayleigh fading model is assumed. Spectrum raised-cosine and Beaulieu-Tan-Damen pulse shapes are employed. Exact closed-form expressions for outage probability with equal and distinct interferers powers are derived. An average bit error rate expression is derived using Gaussian approximation of the cochannel interference. Monte-Carlo simulation is used to validate the Gaussian approximation. The results are valid for arbitrary diversity order and desired user fading parameter. Slow flat fading, asynchronous timing and independent fading gains are assumed.

Precise bit error rate analysis of bandlimited BPSK with EGC and SC diversity in CCI and Nakagami fading [cellular radio]

Equal gain and maximum desired user power selection combining for bandlimited BPSK systems in Nakagami fading with cochannel interference are considered. Spectrum raised-cosine and new Beaulieu-Tan-Damen pulse shapes are employed. Average bit error rates are derived using characteristic function and Fourier series methods for arbitrary orders of diversity and fading parameters. The computational complexity of the solution does not grow with the diversity order. Slow flat fading, asynchronous timing and independent fading gains are assumed. The superiority of the Beaulieu-Tan-Damen pulse over the conventional spectrum raised-cosine pulse in bit error rate performance is observed and the superiority increases with the diversity order.