Influence of nonlinear HPA on trellis-Coded OFDM for terrestrial broadcasting of digital HDTV

Bogenfeld, Eckard; Valentin, R.; Metzer, K.; Sauer-Greff, W.

doi:10.1109/glocom.1993.318310

Cited by 15 publications

(6 citation statements)

References 7 publications

(3 reference statements)

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“…The input signal of the HPA is represented as follows:

x false(t false) = ρ false(t false) e^{j φ (t)},

where ρ ( t ) and φ ( t ) are the amplitude and phase of the signal, respectively. The HPA output signal can be expressed as :

z false(t false) = f false(x (t) false) = A false[ρ (t) false] e^{j {φ false(t false) + Φ false[ρ (t) false]}},

where A [ ρ ( t )] is the amplitude nonlinearity, called AM/AM conversion, and Φ [ ρ ( t )] is the phase nonlinearity, called AM/PM conversion.…”

Section: Brief Review Of Nonlinear Hpa Modelsmentioning

confidence: 99%

“…In the TWTA model, according to the Saleh memory model , the AM/AM and AM/PM characteristics are as follows:

A false[ρ (t) false] = A_{sat}^{2} \frac{ρ (t)}{ρ {(t)}^{2} + A_{sat}^{2}},

Φ false[ρ (t) false] = \frac{π}{3} \frac{ρ {(t)}^{2}}{ρ {(t)}^{2} + A_{sat}^{2}},

where A sat is the amplifier input saturation voltage. In the SSPA model, the functions A [ ρ ( t )] and Φ [ ρ ( t )] are given as :

A false[ρ (t) false] = \frac{ρ (t)}{{[1 + {(\frac{ρ false(t false)}{A_{0}})}^{2 p}]}^{\frac{1}{{2 p}}}},

Φ [ρ (t)] = 0,

where A 0 is the maximum output amplitude and p is a control parameter of the transition from a linear region to a saturation region . Finally, the AM/AM and AM/PM characteristics based on the SEL model are

A [ρ (t)] = \{\begin{matrix} ρ (t) & ρ (t) \leq A_{normalsat} \\ A_{sat} \end{matrix}

…”

Section: Brief Review Of Nonlinear Hpa Modelsmentioning

confidence: 99%

“…where ρ(t) and φ(t) are the amplitude and phase of the signal, respectively. The HPA output signal can be expressed as [25]:…”

Section: Nonlinear Hpa Modelsmentioning

confidence: 99%

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Blind downlink channel estimation for TDD‐based multiuser massive MIMO in the presence of nonlinear HPA

2019

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In time division duplex (TDD)‐based multiuser massive multiple input multiple output (MIMO) systems, the uplink channel is estimated and the results are used in downlink for signal detection. Owing to noisy uplink channel estimation, the downlink channel should also be estimated for accurate signal detection. Therefore, recently, a blind method was developed, which assumes the use of a linear high‐power amplifier (HPA) in the base station (BS). In this study, we extend this method to a scenario with a nonlinear HPA in the BS, where the Bussgang decomposition is used for HPA modeling. In the proposed method, the average power of the received signal for each user is a function of channel gain, large‐scale fading, and nonlinear distortion variance. Therefore, the channel gain is estimated, which is required for signal detection. The performance of the proposed method is analyzed theoretically. The simulation results show superior performance of the proposed method compared to that of the other methods in the literature.

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“…The input signal of the HPA is represented as follows:

x false(t false) = ρ false(t false) e^{j φ (t)},

where ρ ( t ) and φ ( t ) are the amplitude and phase of the signal, respectively. The HPA output signal can be expressed as :

z false(t false) = f false(x (t) false) = A false[ρ (t) false] e^{j {φ false(t false) + Φ false[ρ (t) false]}},

where A [ ρ ( t )] is the amplitude nonlinearity, called AM/AM conversion, and Φ [ ρ ( t )] is the phase nonlinearity, called AM/PM conversion.…”

Section: Brief Review Of Nonlinear Hpa Modelsmentioning

confidence: 99%

“…In the TWTA model, according to the Saleh memory model , the AM/AM and AM/PM characteristics are as follows:

A false[ρ (t) false] = A_{sat}^{2} \frac{ρ (t)}{ρ {(t)}^{2} + A_{sat}^{2}},

Φ false[ρ (t) false] = \frac{π}{3} \frac{ρ {(t)}^{2}}{ρ {(t)}^{2} + A_{sat}^{2}},

where A sat is the amplifier input saturation voltage. In the SSPA model, the functions A [ ρ ( t )] and Φ [ ρ ( t )] are given as :

A false[ρ (t) false] = \frac{ρ (t)}{{[1 + {(\frac{ρ false(t false)}{A_{0}})}^{2 p}]}^{\frac{1}{{2 p}}}},

Φ [ρ (t)] = 0,

A [ρ (t)] = \{\begin{matrix} ρ (t) & ρ (t) \leq A_{normalsat} \\ A_{sat} \end{matrix}

…”

Section: Brief Review Of Nonlinear Hpa Modelsmentioning

confidence: 99%

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Blind downlink channel estimation for TDD‐based multiuser massive MIMO in the presence of nonlinear HPA

2019

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“…With OFDM and other multicarrier schemes, the transmitted signals have large envelope fluctuations (and, consequently, high peak‐to‐mean envelope power ratio and peak‐to‐average power ratio), leading to amplification difficulties . The nonlinear distortion causes both in‐band and out‐of‐band interference to signals.…”

Section: Introductionmentioning

confidence: 99%

Loading techniques for OFDM systems with nonlinear distortion effects

Araujo¹,

Dinis

2011

Trans. Emerg. Telecomms. Techs.

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In this paper, we study the impact of nonlinear distortion effects on adaptive orthogonal frequency division multiplexing systems. An analytical statistical characterisation of the transmitted signals, which is obtained by taking advantage of the Gaussian‐like nature of the orthogonal frequency division multiplexing signals when the number of subcarriers is high, is included. This statistical characterisation is used to evaluate loading algorithms in the presence of strong nonlinear distortion effects and to redefine loading algorithms taking into account nonlinear distortion issues. Copyright © 2011 John Wiley & Sons, Ltd.

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“…Thus a preliminary study of the system is required to find a good trade-off between a maximum output power and degradation due to nonlinear distortions. Some results about OFDM performance in presence of nonlinearity are given in [2,3]. Generally, it is very difficult to mathematically analyze a M-QAM radio system with a nonlinear transmit amplifier and error correction decoding.…”

Section: Introductionmentioning

confidence: 99%

A model for performance evaluation in M-QAM-OFDM schemes in prescence of nonlinear distortions

Santella

Mazzenga

1995 IEEE 45th Vehicular Technology Conference. Countdown to the Wireless Twenty-First Century

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This paper presents a model for a semi-analytic performance evaluation in M-QAM-Orthogonal Frequency Division Multiplexing (OFDM) digital radio systems in the presence of additive white gaussian noise (AWGN) transmission channel and nonlinear distortions due to High Power Amplifier (HPA). It is shown that, in the case of an OFDM system with a large number of sub-carriers, the distortion on the received symbol caused by the amplifier can be modelled, with negligible error, as a It Gaussian nonlinear noise" added to the received symbol. Considering this important remark the semi-analytical approach is only used to estimate means and variances of the %onlinear noise" while these estimated parameters are subsequently used to evaluate the system Bit Error Rate (BER) in a closed form. The advantage of this proposed method is that it strongly reduces the computational time. The proposed procedure is applied to evaluate M-QAM-OFDM performance in presence of nonlinear distortions due to High Power Amplifiers.

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Influence of nonlinear HPA on trellis-Coded OFDM for terrestrial broadcasting of digital HDTV

Cited by 15 publications

References 7 publications

Blind downlink channel estimation for TDD‐based multiuser massive MIMO in the presence of nonlinear HPA

Blind downlink channel estimation for TDD‐based multiuser massive MIMO in the presence of nonlinear HPA

Loading techniques for OFDM systems with nonlinear distortion effects

A model for performance evaluation in M-QAM-OFDM schemes in prescence of nonlinear distortions

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