Upper-bound performance of a wide-band adaptive modem

Wong, C.H.; Hanzo, Lajos

doi:10.1109/26.837037

Cited by 40 publications

(10 citation statements)

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“…The most important performance measures of the adaptive modulation scheme are the average spectral efficiency and the average BER [2]. The spectral efficiency can be calculated as follows [9], [10]…”

Section: Adaptive Modulation On a Perfectly Estimated Channelmentioning

confidence: 99%

Effect of Channel Estimation Errors on Adaptive Modulation Systems Subject to Rayleigh Fading

Lopes¹,

Regis²,

Alencar³

et al. 2011

Anais De XXIX Simpósio Brasileiro De Telecomunicações

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Resumo-A adoção do esquema de modulação adaptativa torna possível a realização de transmissões robustas e espectralmente eficientes. No entanto, o desempenho dos sistemas de modulação adaptativaé afetado pela precisão das informações do estado de canal, o que pode resultar em decisões incorretas do modulador, causando uma degradação da taxa de erro de bit. Neste trabalho, os autores avaliam o efeito dos erros de estimação em sistemas de modulação adaptativa. Um novo arcabouço analíticoé proposto para modelar a relação sinal-ruído estimada instantânea. Diferentemente das abordagens anteriores, este modelo não está relacionado a uma técnica de estimativa específica e pode ser usado para comparar estratégias de estimação de canal com diferentes níveis de precisão. Palavras-Chave-Modulação adaptativa, Erro de estimação do canal, Desvanecimento Rayleigh.Abstract-The adoption of the adaptive modulation scheme leads to robust and spectrally efficient transmissions. However, the performance of the adaptive modulation systems is affected by the accuracy of the channel state information, which can result in incorrect modulator decisions, causing a bit error rate degradation. In this paper, the authors evaluate the effect of channel estimation errors in adaptive modulation systems. A novel analytical framework is proposed to model the instantaneous estimated signal-to-noise ratio. Different from previous approaches, this model is not related to a specific estimation technique and can be used to compare channel estimation strategies with different accuracy levels.

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Section: Adaptive Modulation On a Perfectly Estimated Channelmentioning

confidence: 99%

Effect of Channel Estimation Errors on Adaptive Modulation Systems Subject to Rayleigh Fading

Lopes¹,

Regis²,

Alencar³

et al. 2011

Anais De XXIX Simpósio Brasileiro De Telecomunicações

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“…Sampei et al [151] switched the modulation modes by estimating the signal to cochannel interference ratio and the expected delay spread of the channel. This work has been extended to wideband channels by Wong et al [157], where the received signal also suffers from ISI in addition to amplitude and phase distortions due to the fading channel. In wideband AQAM systems, the channel SNR, the C/I, or RSSI metrics cannot be readily estimated or predicted, among other factors due to the multipath nature of the channel or as a result of the so-called birth-death processes associated with the sudden appearance or disappearance of communicating users.…”

Section: B Channel Quality Metricsmentioning

confidence: 99%

Burst-by-burst adaptive multiuser detection cdma: a framework for existing and future wireless standards

Kuan

Hanzo

2003

Proc. IEEE

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This paper provides a broad overview of the multiuser detection literature of the past few years in a nonmathematical, easily accessible approach. The treatment is then extended to the comparative study of channel-quality controlled burst-by-burst (BbB) adaptive code division multiple access (CDMA) detection such as parallel interference cancellation, successive interference cancellation, and joint detection (JD I. MOTIVATIONMobile propagation channels exhibit time-variant propagation properties [1]. Although, apart from simple cordless telephoneschemes,mostmobileradiosystemsemploypowercontrol for mitigating the effects of received power fluctuations, rapid channel quality fluctuations cannot be compensated by practical, finite reaction-time power control schemes. Furthermore, the ubiquitous phenomenon of signal dispersion due to the multiplicity of scatering and reflecting objects cannot be mitigated by power control. Similarly, other performance lim- iting factors, such as adjacent-channel and cochannel intereference as well as multiuser interference (MUI) vary as a function of time. The ultimate channel quality metric is the bit-error rate (BER), regardless of the specific channel impairments encountered. The channel quality variations are typically higher near the fringes of the propagation cell or when moving from an indoor scenario to an outdoor cell due to the high standard deviation of the shadow fading and fast fading [1] encountered, even in conjunction with agile power control. Furthermore, the bit errors typically occur in bursts due to the time-variant channel quality fluctuations; hence, it is plausible that a fixed transceiver mode cannot achieve a high flexibility in such environments. The design of powerful and flexible transceivers [2]-[4] has to be based on finding the best compromise among a number of contradicting design factors [2]- [4]. Some of these factors are low power consumption, high robustness against transmission errors among various channel conditions, high spectral efficiency, low-delay for the sake of supporting interactive real-time multimedia services, high-capacity networking, and so forth [5]. In this paper, we will address a few of these issues in the context of direct sequence code division multiple access [6] (DS-CDMA) systems, 1 since CDMA is the solution standardized in all three recently ratified global mobile 1 The simple philosophy of DS-CDMA is that a binary bit of a user is signaled to the receiver with the aid of a unique, user-specific signature sequence. The DS spreading sequences may be chosen such that they are orthogonal to each other; hence, the individual users' signals do not interfere with each other, provided that the transmission channel does not destroy the orthogonality of the DS spreading sequences. When the orthogonality of the DS spreading codes is retained at the receiver, no MUI is inflicted; hence, a simple correlator is capable of detecting the codes of the users conveying the information with the aid of the code's polarity. By contrast, if the...

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“…Furthermore, we analyze the effect of the channel spatial correlation.For the case of AM over frequency-selective channels, the literature is less abundant. The performance of the AM over equalized SISO multipath channels has been investigated in [16][17][18][19]. Authors in [16,17] have proposed an AM scheme based on the pseudo signal-to-interference-plusnoise ratio (SINR) at the equalizer output.…”

mentioning

confidence: 99%

Adaptive modulation and decision feedback equalization for frequency‐selective MIMO channels

Ammari

Zaouali

Fortier

2013

Int J Communication

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SUMMARYIn this paper, an adaptive modulation scheme for the multiple‐input multiple‐output (MIMO) frequency‐selective channels is investigated. We consider a scenario with precoded block‐based transceivers over spatially correlated Rayleigh multipath MIMO channels. To eliminate the inter‐block interference, the zero‐padding is used. The receiver is equipped with a MIMO minimum‐mean‐squared‐error decision feedback equalizer. The precoder aims to force each subchannel to have an identical signal‐to‐interference‐plus‐noise ratio (SINR). To adjust the constellation size, the unbiased mean square error at the equalizer output is sent back to the transmitter. To simplify our analysis, the feedback channel is considered as instantaneous and error free. We first derive the probability density function of the overall SINR for flat fading and frequency‐selective channels. On the basis of the probability density function of the upper bound of the SINR, we evaluate the system performance. We present accurate closed‐form expressions of the average spectral efficiency, the average bit error rate and the outage probability. The derived expressions are compared with Monte Carlo simulation results. Furthermore, we analyze the effect of the channel spatial correlation. Copyright © 2013 John Wiley & Sons, Ltd.

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Upper-bound performance of a wide-band adaptive modem

Cited by 40 publications

References 7 publications

Effect of Channel Estimation Errors on Adaptive Modulation Systems Subject to Rayleigh Fading

Effect of Channel Estimation Errors on Adaptive Modulation Systems Subject to Rayleigh Fading

Burst-by-burst adaptive multiuser detection cdma: a framework for existing and future wireless standards

Adaptive modulation and decision feedback equalization for frequency‐selective MIMO channels

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