A blockwise loading algorithm for the adaptive modulation technique in OFDM systems

Grünheid, R.; Bolinth, E.; Rohling, Hermann

doi:10.1109/vtc.2001.956913

Cited by 74 publications

(26 citation statements)

References 2 publications

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“…Increasing the value of Δfτ d results in a lower ρ f (Δf ), and the process tends to become more discrete. This leads to reduced accuracy in formulas (37) and (38).…”

Section: A Subcarrier Link Gain In Siso Ofdmmentioning

confidence: 99%

Block-Based Performance Measures for MIMO OFDM Beamforming Systems

Kongara

Kuo

Smith

et al. 2009

IEEE Trans. Veh. Technol.

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Abstract-In this paper, we consider an adaptive modulation system with multiple-input-multiple-output (MIMO) antennas in conjunction with orthogonal frequency-division multiplexing (OFDM) operating over frequency-selective Rayleigh fading environments. In particular, we consider a type of beamforming with a maximum ratio transmission/maximum ratio combining (MRT-MRC) transceiver structure. For this system, we derive a central limit theorem for various block-based performance metrics. This motivates an accurate Gaussian approximation to the system data rate and the number of outages per OFDM block. In addition to the data rate and outage distributions, we also consider the subcarrier signal-to-noise ratio (SNR) as a process in the frequency domain and compute level crossing rates (LCRs) and average fade bandwidths (AFBs). Hence, we provide fundamental but novel results for the MIMO OFDM channel. The accuracy of these results is verified by Monte Carlo simulations, and applications to performance analysis and system design are discussed.Index Terms-Adaptive modulation, average fade bandwidth (AFB), beamforming, eigenvalues, level crossing rate (LCR), multiple-input-multiple-output orthogonal frequencydivision multiplexing (MIMO OFDM), Rayleigh fading channels.

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“…Increasing the value of Δfτ d results in a lower ρ f (Δf ), and the process tends to become more discrete. This leads to reduced accuracy in formulas (37) and (38).…”

Section: A Subcarrier Link Gain In Siso Ofdmmentioning

confidence: 99%

Block-Based Performance Measures for MIMO OFDM Beamforming Systems

Kongara

Kuo

Smith

et al. 2009

IEEE Trans. Veh. Technol.

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“…A Simple Blockwise Loading Algorithm (SBLA) is proposed in [33]. The algorithm divides the subcarriers into N B blocks of N cb adjacent subcarriers.…”

Section: Adaptive Bit Allocation (Bit Loading)mentioning

confidence: 99%

Cognitive Radio Dynamic Access Techniques

Budiarjo

Лакшманан

Nikookar

2008

Wireless Pers Commun

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The ever growing demand for wireless services has placed enormous burden on valuable resources such as spectral bandwidth. This has resulted in a major rethinking in resource allocation policies culminating in an explosion of research activity in the field of Cognitive Radio (CR) towards optimum resource usage. In this tutorial paper the physical layer design and transmission techniques for CR in the context of efficient spectrum utilization are discussed. Spectrum sensing as the key element of CR awareness is described. Orthogonal frequency division multiplexing (OFDM) as a spectrally efficient modulation scheme is discussed and the rationale for its use in the CR system is explained. Spectrum pooling for efficient use of spectrum is studied and the role of adaptive OFDM techniques in this method is highlighted. Wavelet basis function as a replacement of Fourier transform in OFDM is evaluated. MIMO system as an added value to the CR performance is described. Adaptive Waveform and beamforming as alternative techniques in CR are reviewed.

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“…Grunheid and Rohling [34] reduce the required computation, by using the same power and bit allocation for a block of adjacent sub-channels (sub-band). Keller and Hanzo combine this block (sub-band) based approach with spectral pre-distortion (pre-equalization) of the OFDM symbol in [49] and [50].…”

Section: Water-filling Solution and Bit-loadingmentioning

confidence: 99%

“…To calculate the average BER, we must average (2.33) with respect to u 0 , thus 34) where the error term has been neglected. The expected value term can easily be found from the characteristic function…”

Section: Ber Calculationmentioning

confidence: 99%

A Video Transmission System for Severely Degraded Channels

Pearlman¹,

Saulnier²

2006

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A blockwise loading algorithm for the adaptive modulation technique in OFDM systems

Cited by 74 publications

References 2 publications

Block-Based Performance Measures for MIMO OFDM Beamforming Systems

Block-Based Performance Measures for MIMO OFDM Beamforming Systems

Cognitive Radio Dynamic Access Techniques

A Video Transmission System for Severely Degraded Channels

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