Sum-rate maximisation comparison using incremental approaches with different constraints

In this work, the problem of rate maximisation of multichannel systems is considered. Two greedy allocation approaches using power (GPA) and bit (GBA) loading schemes with a slight difference in design constraints that aiming to maximise the overall system throughput are compared. Both algorithms use incremental bit loading whereby, the GPA is designed with main interest of efficient power utilisation. Whereas, the GBA sacrifices power utilisation to another design issue of achieving an average bit error ratio (BER) less than the target BER. Simulation results shows that with GPA algorithm better throughput is gained over the GBA algorithm while the latter guaranteed less BER

Trade-off between complexity and BER performance of a polynomial SVD-based broadband MIMO transceiver

In this paper we investigate non-linear precoding solutions for the problem of broadband multiple-input multiple output(MIMO) systems. Based on a polynomial singular value decomposition (PSVD) we can decouple a broadband MIMO channel into independent dispersive spectrally majorised single-input single-output (SISO) subchannels. In this contribution, the focus of our work is to explore the influence of approximations on the PSVD, and the performance degradation that can be expected as a result

Reduced complexity schemes to greedy power allocation for multicarrier systems

Discrete bit loading for multicarrier systems based on the greedy power allocation (GPA) algorithm is considered in this paper. A new suboptimal scheme that independently performs GPA on groups of subcarriers and therefore can significantly reduce complexity compared to the standard GPA is proposed. These groups are formed in an initial step of a uniform power allocation (UPA) algorithm. In order to more efficiently allocate the available transmit power, two power re-distribution algorithms are further introduced by including a transfer of residual power between groups. Simulation results show that the two proposed algorithms can achieve near optimal performance in two separate and distinctive SNR regions. We demonstrate by analysis how these methods can greatly simplify the computational complexity of the GPA algorithm

Greedy power allocation for multicarrier systems with reduced complexity

In this paper we consider a reduced complexity discrete bit loading for Multicarrier systems based on the greedy power allocation (GPA) under the constraints of transmit power budget, target BER, and maximum permissible QAM modulation order. Compared to the standard GPA, which is optimal in terms of maximising the data throughput, three suboptimal schemes are proposed, which perform GPA on subsets of subcarriers only. These subsets are created by considering the minimum SNR boundaries of QAM levels for a given BER. We demonstrate how these schemes can reduce complexity. Two of the proposed algorithms can achieve near optimal performance by including a transfer of residual power between groups at the expense of a very small extra cost. It is shown that the two near optimal schemes,while greatly reducing complexity, perform best in two separate and distinct SNR regions

Incremental rate maximisation power loading with BER improvements

This paper aims to maximise the rate over a MIMO link using incremental power and bit allocation. Two different schemes, greedy power allocation (GPA) and greedy bit allocation (GBA), are addressed and compared with the standard uniform power allocation (UPA). The design is constrained by the target BER, the total power budget, and fixed discrete modulation orders. We demonstrate through simulations that GPA outperforms GBA in terms of throughput and power conservation,while GBA is advantageouswhen a lower BER is beneficial. Once the design constraints are satisfied, remaining power is utilised in two possible ways, leading to improved performance of GPA and UPA algorithms. This redistribution is analysed for fairness in BER performance across all active subchannels using a bisection method

Konsep Belajar Dan Pembelajaran

: Learning and instruction are the two concepts that are related to each other, and they cannot be separated. Both of them are the main activities in education. Learning is defined as the process of changing behavior as a result of individual interaction with their environment. The changing of behavior is continuous, functional, positive, and directed. The process of changing behavior stimulated in many different conditions based on the explanation from educational and psychological experts. Instruction is defined as the activities processing from planning, implementation, and evaluation. Instruction is the effort to facilitate students\u27 learning. Instruc­tion is also defined as the interaction of students, educators, and learning resources in a learning environment. Therefore, the effectiveness of ins­truction is determined by the interaction of these three components

Einstein Geometrization Philosophy and Differential Identities in PAP-Geometry

The importance of Einstein's geometrization philosophy, as an alternative to the least action principle, in constructing general relativity (GR), is illuminated. The role of differential identities in this philosophy is clarified. The use of Bianchi identity to write the field equations of GR is shown. Another similar identity in the absolute parallelism geometry is given. A more general differential identity in the parameterized absolute parallelism geometry is derived. Comparison and interrelationships between the above mentioned identities and their role in constructing field theories are discussed.Comment: LaTeX file, 17 pages, comments and criticism are welcom

Biochemical and histological study on the effect of levetiracetam on the liver and kidney of pregnant albino rats

Background: Levetiracetam is a broad-spectrum antiseizure agent and one of the most commonly prescribed drugs for epilepsy. The aim of this work was to assess the effect of levetiracetam at its therapeutic range on the liver and kidney of pregnant albino rats. Materials and methods: Forty pregnant rats were divided equally into two groups (I–II), Rats in the group I were gavaged 1.5 mL/day distilled water in two divided doses throughout pregnancy. Rats in the group II were gavaged 1.5 mL/day distilled water (containing 36 mg levetiracetam) in two divided doses throughout pregnancy. At the end of the experiment, blood samples were taken and the sera were separated and used for biochemical analysis. The kidneys and livers of both groups were excised and used for light and electron microscopic examination. Results: Treatment with levetiracetam induced undesirable histopathological changes in the liver and kidney of pregnant albino rats. These changes were in the form of distortion of the hepatic architecture, dilatation of the central and the portal veins, widening of the Bowman’s spaces, thickening and disruption of the glomerular basement membrane, fusion and effacement of secondary foot processes, cytoplasmic vacuolation, and swollen mitochondria with loss of their cristae. Such changes were confirmed by alteration of certain biochemical parameters related to the liver and kidney functions. Conclusions: Levetiracetam induced deleterious effects on the liver and kidney of pregnant albino rats. Further investigations are recommended to clarify the mechanism of levetiracetam toxicity