Hasil Pencarian  ::  Simpan CSV :: Kembali

"Ketidakseimbangan kapasitas antara kanal uplink dan kanal downlink pada pelapisan narrowband COMA dan wideband COMA dianalisa dengan menggunakan kontrol daya berbasis SIR. Kanal uplink dan kanal downlink tidak dioperasikan didalam suatu kondisi yang serupa maka kapasitas antara uplink dan downlink berbeda dan salah satu dari dua link menentukan keseluruhan kapasitas sistem. Link mana yang membatasi kapasitas sistem dan apa yang merupakan faktor pembatasan diselidiki. Uplink seringkali membatasi keseluruhan kapasitas jika kontrol daya downlink efektif. Aktifitas pengguna berperan paling utama didalam menentukan pembatasan link menyangkut kapasitas koneksi. Penggunaan bandwidth yang efisien akan membentuk layanan yang sedemikian rupa sehingga pertentangan keseluruhan aktifitas bisa dikurangi. Peningkatan kapasitas berhubungan erat dengan kontrol daya, bagaimanapun didalam sistem kontrol daya berb3sis SIR memelihara (Eb-Io) pada suatu level yang diinginkan. Kita menerapkan metoda kalkulasi yang berulang menyangkut mean dan variance dari interferensi yang dipertimbangkan untuk kontrol daya yang berbasis SIR. Kemudian hasil kapasitas transmisi dan kapasitas koneksi antara uplink dan downlink dengan penerapan kontrol daya SIR dibandingkan.

---

Capacity unbalance between uplink and downlink in spectrally overlaid narrow-band and wide-band COMA is analyzed by using SIR-based power control. Uplink and downlink channel are not operated in an identical condition, the capacity between uplink and downlink are unequal and either of links determines the whole system capacity. Which links limits the system capacity and what are the limiting factors. Uplink often limits the overall capacity if downlink power control is effective. The users activities plays the most important role in determining the limiting link of connection capacity. The efficiently utilize the bandwidth should devote their efforts to forming services so that the overall activity discrepancy could be mitigated. Increasing capacity has close relationship with power control, by the way in SIR-based power control keep (Eb-Io) in expected. We use calculation method the looping about mean and variance of interference that consider SIR-based power control. Than the result from transmission capacity and connection capacity between uplink and downlink by using power control SIR are compared."

"This paper will analyze the performance of adaptive slotted ALOHA DS-CDM4 over multipath fading with capture eject to increase throughput transmit data when traffic condition in saturation. To divine intervention we use algorithm to control level change transmission rate use user based on trqffic condition. Adaptive slotted ALOHA DS-CDA/L4 technique is technique access can do adaptation level transmission rate based trams condition. Using protocol access channel adaptive slotted ALOHA DS-CDAM combine between slotted ALOHA and DS-CDMA in wireless communication system. This method may users to do access simultaneously and using efficient spectrum is providential from adaptive slotted ALOHA DS-CDMA Performance of S-ALOHA DS-CDMA decrease on channel fading. To handle throughput decrease because amount bit on transmit packet, so capture effect can use to handle this problem. So effective throughput depend capture probability and probability packet success. From that result throughput adaptive slotted ALOHA DS-CDMA with capture eject on multipath fading channel increase with decrease capture ratio length bit packet and different number of path."

"Throughput S-ALOHA CDM4 using technique of diversities MRC differential detected with L branch antenna has been analyzed Desired signal will be intercepted then combined and also analyzed the influence of co channel interference. By using two different model of fading between desired signal and interference signal, throughput can he analyzed under channel condition of Nakagami/ Nakagami and Rician/Nakagami. MRC diversities and differential detection (DPSK) with L branch antenna are used on receiver to overcome multi path fading interference and to increase the system performance. From the result indicating the use of L branch antenna at receiver make .system throughput becomes better The higher the amount of interference signals the worse throughput system. The bigger Nakagami parameter m, and Rician factor, K, of the desired signal and interference signal the better the throughput."

"Code division multiple access (CDMA) S-ALOHA adalah teknik akses yang menggabungkan CDMA dan S-ALOHA yang memiliki kinerja yang Iebih baik dari elemen pendukung CDMA ataupun S-ALOHA sendiri. Teknik akses CDMA S-ALOHA sangat mendukung integrasi suara, data dan video (multimedia) yang sangat diperlukan untuk komunikasi masa depan. Analisis kinerja bit error rate (BER) CDMA yang biasa dilakukan adalah dengan pendekatan Gaussian (Gaussian Approximation, GA) pada pendekatan ini pengaruh multiple acces interference (MAI) diasumsikan sebagai noise. Untuk meningkatkan keakuratan BER maka digunakan Improved GA (IGA). Kinerja CDMA S-ALOHA akan lurun dikarenakan adanya fading, interferensi dan peningkatan data rate pengguna.Pada disertasi ini dianalisa kinerja throughput CDMA S-ALOHA pada kanal fading dengan capture eject menggunakan pendekatan IGA. Penggunaan capture effect diusulkan untuk meningkatkan kinerja Sistem pada kanal dengan adanya fading dan interferensi. Oleh karena itu perlu dievaluasi pengaruh capture effect dalam meningkatkan kinerja sistem. Dimana capture effect yang digunakan adalah delay capture effect.Kinerja throughput CDMA S-ALOHA yang dianalisa dilakukan secara matematis. Kontribusi dari penelitian ini adalah penurunan persamaan matematis throughput CDMA S-ALOHA yang didapatkan dari sistem model CDMA S-ALOHA pada kanal fading dengan capture effect. Pada disertasi ini analisa kinerja CDMA S-ALOHA meliputi :a. Throughput CDMA S-ALOHA pada kanal fading dengan capture effect. Pada Sistem ini kinerja CDMA S-ALOHA dievaluasi dengan pendekatan IGA untuk meningkatkan keakuratan sistem dibandingkan GA. Dari hasil terlihat bahwa sistem CDMA S-ALOHA dengan capture eject memiliki kinerja throughput yang tinggi.b. Throughput CDMA S-ALOHA pada kanal fading Nakagami/Nakagami dengan capture effect. Pada sistem ini dua model fading digunakan untuk memodelkan fading pada sinyal utama dan sinyal interferensi yang diasumsikan memiliki kedalaman fading yang berbeda. Model fading adalah Nakagami/Nakagami yang masing-masing untuk memodelkan fading pada sinyal utama dan interferensi. Dari hasil yang diperoleh terlihat bahwa sistem dengan capture effect sempurna memiliki kinerja throughput yang paling baik. Makin besar nilai capture effect-nya makin rendah throughput yang dihasilkan.c. Throughput sistem Adaptive CDMA S-ALOHA pada kanal fading dengan capture effect. Sistem Adaptive CDMA S-ALOHA digunakan untuk mengatasi penurunan throughput akibat peningkatan data rate dari pengguna, sedangkan capture effect digunakan untuk mengatasi fading yang terjadi pada kinerja sislem. Dari hasil diperoleh bahwa throughput Adaptive CDMA S-ALOHA lebih tinggi dari pada throughput CDMA S-ALOHA, sistem dengan capture effect sempurna memiliki hasil throughput yang paling baik.Dari ketiga model yang dianalisa terlihat bahwa penggunaan capture effect telah dapat meningkatkan kinerja throughput CDMA S-ALOHA pada kanal fading.

---

ALOHA Code Division Multiple Access (CDMA) is a combined access technique between CDMA and S-ALOHA which has superior performance compare to its supporting elements and S-ALOHA itself S-ALOHA CDMA access technique has been used to support voice, data and video (multimedia) integration which is desperately needed to support future communication. The CDMA bit enor rate (BER) performance analysis is usually perfomied in Gaussian Approximation (GA) in which the effects of Multiple Access Interference (MAI) have been assumed as noises. Improved Gaussian Approximation (IGA) technique has been used to improved BER system. The performance of S-ALOHA CDMA has been decline due to fading, interference and the increase of users? data rate.

In this dissertation, the throughput performances of S-ALOHA CDMA for users? voice and data integration over fading channel with capture effect using [GA have been analysed. The capture effect is used to improve system?s performance with fading and interference. So, capture effect impact in improving system performance need to be analysed. Capture effect used is delay capture effect.

S-ALOHA CDMA throughput performance has been mathematically analysed. The main contribution from this dissertation is the derivation of mathematical expression to represent the throughput of S-ALOHA CDMA that is obtained from S-ALOHA CDMA model system on fading channel with capture effect. ln this dissertation, the performance analysis of ALOHA CDMA is as follows:

a. S-ALOHA CDMA throughput over fading channel with capture effect. In this system, the performance of S-ALOHA CDMA has been evaluated using IGA to improve its system accuracy compared to conventional GA. It is Shown from the result that S-ALOHA CDMA with capture effect has high throughput performance.

b. S-ALOHA CDMA throughput over Nakagamifhlakagami fading channel with capture effect. In this system. two fading models have been used to model effects of fading on the desired and interference signal which is assumed to have different fading models. Fading model employed is Nakagami/Nakagami, each is used to model fading on the desired signal and the interference. From the result obtained, the perfect capture effect system has the best throughput performance. The increase of capture effect rate make the throughput yielded decrease.

c. Throughput of the Adaptive S-ALOHA CDMA over fading channel with capture effect. Adaptive S-ALOHA CDMA system has been used to overcome the decrease of throughput as a result ofthe increase of data rate from the users, and the capture effect has been used to overcome the effect of fading occurs on the systems. From the result obtained, S-ALOHA CDMA Adaptive throughput is higher than the S-ALOHA CDMA throughput. System with capture effect results the best throughput. It has been proven that the performance of S-ALOHA CDMA over multipath fading channels and throughput system can increase when capture effect is applied."