Spectrum sensing is the key component of cognitive radio technology. Spectrum sensing is a tough task because of shadowing, fading, and time-varying nature of wireless channels. However, detection is compromised when a user experiences shadowing or fading effects. In such cases, user cannot distinguish between an unused band and a deep fade. Thus, cooperative spectrum sensing is proposed to opt...

In this paper, we propose an online SNR estimation scheme for generalized fading channels. We derive the SNR estimate based on a statistical ratio of observables over a block of data, when the channel undergoes Nakagami fading. An online SNR estimator for AWGN channels has been derived recently by Summers and Wilson. Our SNR estimation scheme in this paper is for a general Nakagami fading chann...

An assessment of spectrum efficiency for a microcellular land mobile radio system is presented by considering the desired signal as (fast) Rician fading with (slow) lognormal shadowing and co-channel interfering signals as uncorrelated (fast) Rayleigh fading superimposed over (slow) lognormal shadowing. Spectrum efficiency is defined in terms of reuse distance, Le., cluster size, traffic intens...

The fast transmission power control problem in a cellular network is studied when the signal attenuation is subject to a fast time-varying multipath Rayleigh fading. An asymptotic representation of the link gain evolution in time is first derived, and then used for constructing a Fast Time Variant distributed constrained Power Control (FTVPC). The proposed FTVPC power control successfully count...

Multipath fading is a major problem of the wireless communication channel. To eliminate this fading problem and to have reliable communications in wireless channel, channel coding techniques are used. In this paper BER (bit error rate) performance is shown, by the means of Rayleigh and Rician multipath fading channels. Here the convolution encoding is used. The performance of convolution encode...

This paper presents performance comparison of various modulation techniques in almouti scheme with Rayleigh fading channel. In the comparison, the space time coding has been used. The performance comparison are made on the basis of symbol error rate(SER) performance matrices over Rayleigh fading channel with 16-PSK,QPSK,PAM,16-QAM,64-QAM modulation technique. The comparison results show that in...

Introduction: Cascaded Rayleigh distribution is used to model multipath fading in mobile-to-mobile communication scenarios and provides a better fit to experimental data in such scenarios compared to the conventional Rayleigh channel model, see [1] and references therein. Although there is a vast literature dedicated to the performance analysis over Rayleigh fading channels, there are only a fe...

This paper presents performance comparison of various modulation techniques in Rayleigh fading channel. In the comparison, the space time coding has been used. The performance comparison are made on the basis of bit error rate(BER) and symbol error rate(SER) performance matrices over Rayleigh fading channel with BPSK,QPSK,8PSK and QAM modulation technique. The comparison results shows that in R...

Abstract—We present an new method for the analytical calculation of the error probability in a Rayleigh fading channel with correlated fading amplitudes. Even though the method can be applied for more general problems, we restrict ourselves on the investigation of a multicarrier CDMA transmission. The frequency correlation between the fading amplitudes of the carriers is given by the delay powe...

This paper considers the channel capacity of 60GHz wireless communications systems over Rayleigh fading channels and Ricean fading channels. The SNR and therefore capacity varies according to the communication distance. The capacity is presented for line-of-sight (LOS) and non-line-of-sight (NLOS) channels given based on a 60GHz link budget model. Phase shift keying (PSK) modulation is consider...