6 research outputs found
Improved Predictive Power Control Algorithms to Increase CDMA System Capacity
No full textIn this paper capacity of CDMA system is evaluated using an improved algorithm of channel prediction-based power control in Rayleigh fading channel environments. One of the most serious problems which degrades the performance of power control algorithm is the effect of feedback delay. To overcome the effect of feedback delay, power control algorithm relies on channel prediction techniques, which utilize the correlation property of the past channel measurements. In CDMA power control, however, the correlation property of channel measurements is destroyed because the transmit power is continuously updated for each power control interval. In order to restore the correlation property of the channel, the past channel measurements are compensated for by the same factors that were given by power updating for each power control interval. The prediction algorithm in this paper is proposed using the least mean square (LMS) technique. The result shows that the capacity of CDMA systems increase significantly when the improved predictive algorithm is used. Numerical evaluation shows that CDMA capacity increases by more than 40 % for fixed step algorithm and more than 50 % for variable step algorithm when the proposed algorithm is employed
Improved Predictive Power Control of CDMA System in Rayleigh Fading Channel
Get PDFIn this paper an improved prediction-based power control is proposed for code division multiple access (CDMA) systems in Rayleigh fading channel environments. One of the most serious problems which degrades the performance of power control algorithm is the effect of feedback delay. To overcome the effect of feedback delay, power control needs to employ prediction algorithm which utilises the correlation property of the past channel samples measurements to predict the future sample values. In CDMA power control, however, the correlation property of channel measurements is destroyed because the transmit power is continuously updated for each power control interval. The prediction algorithm in this paper uses the recursive least square (RLS) technique and an improved predictor algorithm is proposed to compensate for the channel correlation. The result shows that the performance of improved predictive power control proposed in this paper evaluated in terms of bit error rate (BER) as a function of bit energy-tointerference power density ratio Eb/Io improved significantly from that of the conventional predictor
Improved Predictive Power Control Algorithms to Increase CDMA System Capacity
Get PDFIn this paper capacity of CDMA system is evaluated using an improved algorithm of channel prediction-based power control in Rayleigh fading channel environments. One of the most serious problems which degrades the performance of power control algorithm is the effect of feedback delay. To overcome the effect of feedback delay, power control algorithm relies on channel prediction techniques, which utilize the correlation property of the past channel measurements. In CDMA power control, however, the correlation property of channel measurements is destroyed because the transmit power is continuously updated for each power control interval. In order to restore the correlation property of the channel, the past channel measurements are compensated for by the same factors that were given by power updating for each power control interval. The prediction algorithm in this paper is proposed using the least mean square (LMS) technique. The result shows that the capacity of CDMA systems increase significantly when the improved predictive algorithm is used. Numerical evaluation shows that CDMA capacity increases by more than 40 % for fixed step algorithm and more than 50 % for variable step algorithm when the proposed algorithm is employed.
Creating and Measuring An Effective Web Design for Investment Simulation Application Website using Technology Acceptance Model (TAM)
Get PDFWeb design is one of the most important factor of a website that determined whether the user like the website or not. Because visual design is the very first thing that anyone will experience when the open the website. It does not matter whether the website is actually useful, if the user simply does not like the design they will leave immediately. When someone look or experience at something new at that moment they immediately decide whether or not they like it. This impression is called first impression. In a research of emotion for example, in a book “Very first impressions” (Bar et al., 2006) the author stated that consistent first impressions can be formed very quickly based on whatever information perceive within 39 milliseconds.
In this research we will try to create a design for a new website called Yokinvestasi.com and find out how much does the user like the website. Yokinvestasi.com is an online simulation application aimed to help investor to calculate how much does they have to spent to invest as efficiently as possible. The simulation utilize the single index model to calculate the investment portfolio part. Because Yokinvestasi.com is a new website, the design is also still new. That is why this research aimed to find out if the user accept the website or not.
For this research to be conducted, we use the model of technology acceptance model to measure how does the user perceived the website Yokinvestasi.com in the field of usefulness and the ease of use. We also measure whether the user will return to use Yokinvestasi.com again in the future by collecting behavioral intention data. To obtain these data we use online questioner by the help of google form and share it to the user. By the end of this research we have obtain 109 valid respondent. The respondent have answer of total 13 question, 5 perceived usefulness question, 5 perceived ease of use question, and 3 behavioral intention question.
Based on the result of this research, the design of Yokinvestasi.com can be improved even further to increase the average score of both the perceived usefulness and perceived ease of use. For example, the mobile design based on the respondent answer is still lacking and hard to use. This is because the plug-in google docs inside the website is simply too big for mobile screen. The image and data simply does not scale well for mobile use. Other than the mobile design, Yokinvestasi.com is still lack of other functionality other than the investment decision support system. For Yokinvestasi.com to thrive in the future, these suggestion must be taken to the core.
Keywords: Technology Acceptance Model, Web Design, Perceived Usefulness, Perceived Ease of Use, Behavioral Intention, Yokinvestasi.co
IMPROVED PREDICTIVE POWER CONTROL OF CDMA SYSTEM IN RAYLEIGH FADING CHANNEL
Get PDFIn this paper an improved prediction-based power control is proposed for code division multiple access (CDMA)systems in Rayleigh fading channel environments. One of the most serious problems which degrades the performanceof power control algorithm is the effect of feedback delay. To overcome the effect of feedback delay, power controlneeds to employ prediction algorithm which utilises the correlation property of the past channel samples measurementsto predict the future sample values. In CDMA power control, however, the correlation property of channelmeasurements is destroyed because the transmit power is continuously updated for each power control interval. Theprediction algorithm in this paper uses the recursive least square (RLS) technique and an improved predictor algorithmis proposed to compensate for the channel correlation. The result shows that the performance of improved predictivepower control proposed in this paper evaluated in terms of bit error rate (BER) as a function of bit energy-tointerferencepower density ratio Eb/Io improved significantly from that of the conventional predictor.Keywords: CDMA, least mean square, power control, prediction, rayleigh fadin
