Optimal and suboptimal adaptive algorithms for rate and power transmission in OFDM-based Cognitive Radio systems

Khederzadeh, Reza; Farrokhi, Hamid

doi:10.1016/j.compeleceng.2015.01.008

Cited by 6 publications

(8 citation statements)

References 20 publications

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“…These constraints cause from PU activity. In [12] authors indicated that if the SU uses uniform loading algorithm the transmission power can be calculated from:…”

Section: Conventional Algorithmsmentioning

confidence: 99%

“…If the SU uses MQAM modulation and uses water filling algorithm, the transmission power is corresponding to minimum values of Equation (31) and Equation (32) [12]:…”

Section: Conventional Algorithmsmentioning

confidence: 99%

“…Although suboptimal algorithms have worse performance than the optimal algorithm but due to their low-complexity procedures, they are the better candidate for practical usages. In [12] authors considered both adaptive modulation and power allocation and introduced a suboptimal power allocation algorithm for OFDM-based CR systems. In the [8] and [12], researchers considered MQAM modulation technique for transmitting data.…”

Section: Introductionmentioning

confidence: 99%

“…In [12] authors considered both adaptive modulation and power allocation and introduced a suboptimal power allocation algorithm for OFDM-based CR systems. In the [8] and [12], researchers considered MQAM modulation technique for transmitting data. In the both papers, modulation level is changed adaptively, based on the channel state information.…”

Section: Introductionmentioning

confidence: 99%

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Adaptive resources assignment in OFDM-based cognitive radio systems

Razmi

Parhizgar

2019

IJECE

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Spectrum efficiency of orthogonal frequency division multiplexing (OFDM)-based cognitive radio (CR) systems can be improved by adaptive resources allocation. In resources allocation, transmission resources such as modulation level and transmission power are adaptively assigned based on channel variations. The goal of this paper is maximize the total transmission rate of secondary user (SU). Hence, we investigate adaptive power and modulation allocation to achieve this purpose. For power allocation, we investigate optimal and conventional methods and then introduce a novel suboptimal algorithm to calculate the transmission power of each subcarrier. In addition, for adaptive modulation, we consider two kinds of modulations including multi-quadrature amplitude modulation (MQAM) and multi-phase-shift keying (MPSK). Also, simulation results are indicated the performance of our algorithm.

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“…These constraints cause from PU activity. In [12] authors indicated that if the SU uses uniform loading algorithm the transmission power can be calculated from:…”

Section: Conventional Algorithmsmentioning

confidence: 99%

“…If the SU uses MQAM modulation and uses water filling algorithm, the transmission power is corresponding to minimum values of Equation (31) and Equation (32) [12]:…”

Section: Conventional Algorithmsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Adaptive resources assignment in OFDM-based cognitive radio systems

Razmi

Parhizgar

2019

IJECE

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“…In [13], the power allocation problems for a two-way OFDM-based CR network to maximize the ergodic sum rates of the SUs were investigated. In [14], a low-complex suboptimal power allocation algorithm was proposed for an OFDM-based CR network to maximize the SU sum rates.…”

Section: Introductionmentioning

confidence: 99%

Minimum BER Power Allocation for OFDM-based Cognitive Radio Networks

2015

KSII TIIS

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In this paper, the optimal power allocation algorithm that minimizes the aggregate bit error rate (BER) of the secondary user (SU) in a downlink orthogonal frequency division multiplexing (OFDM) based cognitive radio (CR) system, while subjecting to the interference power constraint and the transmit power constraint, is investigated under the assumption that the instantaneous channel state information (CSI) of the interference links between the secondary transmitter and the primary receiver, and between the primary transmitter and the secondary receiver is perfectly known. Besides, a suboptimal algorithm with less complexity is also proposed. In order to deal with more practical situations, we further assume that only the channel distribution information (CDI) of the interference links is available and propose heuristic power allocation algorithms based on bisection search method to minimize the aggregate BER under the interference outage constraint and the transmit power constraint. Simulation results are presented to verify the effectiveness of the proposed algorithms.

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