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Changkyu Seol,Kyungwhoon Cheun,Sungnam Hong IEEE 2010 IEEE communications letters Vol.14 No.11
<P>In this letter, an approximation to the performance of downlink cellular orthogonal frequency division multiple access networks under log-normal shadowing and Ricean fading is evaluated. The interference statistic is shown to significantly deviate from the Gaussian distribution as shown in previous results under Rayleigh fading.</P>
Sungnam Hong,Changkyu Seol,Kyungwhoon Cheun IEEE 2011 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.59 No.4
<P>In this paper, we analyze the performance of soft decision decoded, synchronous, fast frequency-hopping spread-spectrum multiple-access networks using M-ary frequency shift keying in Rayleigh fading channels under the assumption that the number of frequency hopping slots is sufficiently large. The joint probability density function (pdf) of the absolute values of the correlator outputs is derived to compute the channel capacity and evaluate the soft decision decoding performance of the 3GPP Turbo and convolutional codes. Results indicate that soft decision decoding based on the derived pdf drastically outperforms traditional decoders based on the Gaussian approximation of the effect of the multiple access interference (MAI). The sensitivity of the derived soft decision decoder to estimation errors in system parameters and the required computational complexities of the derived soft decision decoding metrics are also investigated.</P>
Son, Jaeyong,Seol, Changkyu,Cheun, Kyungwhoon,Yang, Kyeongcheol IET 2016 IET COMMUNICATIONS Vol.10 No.1
<P>In this study, the coverage of downlink cellular orthogonal frequency-division multiple-access networks transmitting one quadrature-amplitude modulation symbol per hop is analysed. The coverage probability is first defined by using an upper bound on the bit error rate (BER) of a bit-interleaved coded modulation system. Moreover then, the moment generating functions of the legacy Gaussian and Laplacian metrics (LMs) for soft-decision decoding of an employed error-correcting code are derived for computing the upper bound on the BER and the corresponding coverage probability of the networks. Numerical results demonstrate that due to the impulsive nature of the inter-cell interference for moderate-to-small cell loads, the networks using the LM for soft-decision decoding significantly outperform those employing the legacy Gaussian metric in terms of the achievable cell radius and the amount of the average transmit power reduction.</P>