On the Bit Error Rate of Opportunistic Wireless Systems that Employ Non-Square Quadrature Amplitude Modulations

Hidalgo, Francisco Toapanta; Garzón, Nathaly Verónica Orozco; Mora, Henry Ramiro Carvajal; Freire, José Julio

doi:10.1109/etcm48019.2019.9014876

Cited by 3 publications

(7 citation statements)

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“…Obviously, it is important to remember that the K factor depends on the position of the transmitter in relation to the receiver [34]. Moreover, from (40), the SE of the opportunistic system using 8-QAM is ξ = 2 3 log 2 (8) = 2 bits/s/Hz and the SE of the opportunistic system using 1024-QAM is ξ = 20 3 ≈ 6.67 bits/s/Hz. By the above, OpT reduce the SE by a factor of q, but, due to the impressive performance gain, it is possible to use very high modulations and still guarantee a low ABEP with reasonable values of SNR.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…(8.350.1)]. Thus, replacing (27) in (20), we obtain an approximate expression to evaluate the ABEP of opportunistic systems operating with S-QAM in Rician fading channels, given by…”

Section: Average Bit Error Probabilitymentioning

confidence: 99%

“…Closed-form expressions to evaluate the BEP of secondary users are derived for Rayleigh fading channels. The ABEP of non-square quadrature amplitude modulations (NS-QAM) is analyzed in [20], where Rayleigh fading is considered, and the performance is evaluated via simulations for 8-QAM and 32-QAM. Square and non-square constellations are necessary for varying channel conditions and rate requirements [21].…”

Section: Introductionmentioning

confidence: 99%

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On the Bit Error Probability and the Spectral Efficiency of Opportunistic Wireless Transmissions in Rician Fading Channels

et al. 2021

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Opportunistic systems take advantage of the wireless communication channel random behavior, since transmission is made only when fading amplitude is above a threshold value, which is calculated based on a transmission probability. This type of transmission draws attention because improves the system performance, and it is an interesting scheme for primary users in cognitive radio networks or is also an option for physical layer security. In this paper, we analyze the performance of opportunistic transmissions in Rician fading channels considering square-quadrature-amplitude-modulation (S-QAM) and nonsquare-quadrature-amplitude-modulation (NS-QAM). Exact closed-form expressions and approximations are derived to evaluate the average bit error probability (ABEP). An expression to calculate the mean spectral efficiency (SE) is also derived considering that a target ABEP must be guaranteed. The SE is calculated using the coverage radius obtained for each modulation used in the system. Hence, an algorithm for the radii calculation is also presented, which considers that the parameters of the Rician fading channel change in the cellular area. The results show that opportunistic transmission (OpT) mitigates the fading effects once the ABEP decays exponentially as the signal to noise ratio (SNR) is increased. Additionally, the proposed algorithm, along with the derived expressions, determine the scenarios where the SE is maximized. INDEX TERMS Opportunistic system, Rician fading channel, modulations, bit error probability, spectral efficiency.

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Section: Numerical Resultsmentioning

confidence: 99%

“…(8.350.1)]. Thus, replacing (27) in (20), we obtain an approximate expression to evaluate the ABEP of opportunistic systems operating with S-QAM in Rician fading channels, given by…”

Section: Average Bit Error Probabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Bit Error Probability and the Spectral Efficiency of Opportunistic Wireless Transmissions in Rician Fading Channels

et al. 2021

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“…For regular hexagonal QAM of n layers, the relation between the total number of constellation points M and layers n is shown in Equation (1), and the relation between the maximum amplitude A m and layers M is as follows:…”

Section: A Information Capacity and Noise Tolerancementioning

confidence: 99%

“…Meanwhile, some scholars have also studied non-rectangular QAM constellations. Literature [1] studied the non-square quadrature amplitude modulations (NS-QAM), particularly, 8-QAM and 32-QAM constellations are considered. Monte-Carlo simulations and comparisons between the performance of S-QAM and NS-QAM are carried out in some relevant scenarios.…”

Section: Introductionmentioning

confidence: 99%