Radio Resources Allocation Based-on Energy Saving for LTE-Advanced System

To fulll the demand of high speed data rate, 3GPP introduced Carrier Aggregation (CA) to support wider transmission bandwidth and spectrum eciency. CA becomes the new standard on LTE-Advanced system. With CA, user can be scheduled on multiple carriers. Since the frequency of each carrier are dierent, there are some differences in coverage and fading characteristic as well. This condition makes the performance of allocation algorithm decreased, especially in energy and spectral eciency. This work proposed some method to improve the performance of resources allocation algorithm in CA system. The methods are user-chunk grouping (UCG) and waterlling (WF) power allocation. UCG process will classify each user and resource in several group, according to fading characteristic of each carrier. Meanwhile, the WF power allocation will distribute power for each resource, so the energy is not wasted on bad channel. The allocation algorithm performance in CA system can be repaired by adding the UCG and IWF method. In varied users (75-250 users), the spectral eciency of proposed algorithm increased by 1.5057 bps/Hz in average and energy eciency increased by 188.21 kbps/Watt in average compared with original MG algorithm. But, in the other hand by adding UCG and WF method, the fairness of the system decreased about 0.295

ANALISIS PENGGUNAAN ALGORITMA RESOURCE SCHEDULING BERDASARKAN USER GROUPING UNTUK SISTEM LTE-ADVANCED DENGAN CARRIER AGGREGATION

Teknologi komunikasi mengalami perkembangan yang sangat cepat. Third Generation Partnership Project (3GPP) telah mengenalkan LTE sebagai generasi jaringan seluler yang selanjutnya akan memenuhi permintaan terhadap komunikasi mobile. Dengan bertambahnya permintaan akan akses yang lebih cepat, maka dikeluarkan dan dikembangkanlah sistem LTE-Advance (LTE-A) oleh fourth generation (4G) mobile system. 3GPP kembali memperkenalkan teknologi baru yaitu Carrier Aggregation (CA) untuk mendukung bandwidth transmisi yang lebih lebar dan efisiensi spektrum. CA menjadi standar baru di sistem LTE-Advanced. Dengan adanya sistem CA ini, setiap user dapat dijadwalkan pada beberapa carrier secara bervariasi. Karena perbedaan frekuensi untuk setiap carrier, maka berbeda pula fading dan cakupan untuk tiap carriernya. Fairness dalam alokasi resources block tidak bisa dicapai dengan algoritma penjadwalan proportional fair (PF) konvensional, karena algoritma PF mengasumsikan semua user dapat dijadwalkan pada seluruh carrier. Maka dibuatlah algoritma modifikasi PF dengan mengelompokkan user terlebih dahulu sesuai dengan jumlah carrier yang dapat diberikan kepada user tersebut yaitu algoritma user grouping-PF (UG-PF) yang menambahkan perbandingan jarak dalam proses alokasi dan algoritma modified user grouping-PF (mUG-PF) yang membagi user dan RB pada beberapa grup spesifik. Dalam Tugas Akhir ini parameter yang diamati adalah average user throughput dan fairness. Dari hasil simulasi, didapatkan algoritma modifikasi PF (UG-PF dan mUG-PF) memiliki tingkat fairness sistem yang lebih baik. Pada Algoritma mUG-PF tingkat fairness naik 0,017-0,109. Sedangkan Untuk algoritma UG-PF tingkat fairness naik sebanyak 0,015-0,073 dibanding algoritma PF konvensional. Sementara pada sisi average user throughput algoritma UG-PF mengalami penurunan sebesar 306-1720 kbps dan algoritma mUG-PF mengalami penurunan sebesar 715-4260 kbps dibanding dengan algoritma PF konvensional. Kata kunci: Carrier aggregation, User grouping, Proportional fair, LTE-Advance

Perfomance Comparison of Genetic and Greedy Algorithms in Underlay Device-to-Device Communication

The number of cellular users (CU) continues to increase in Indonesia. This impacts a large network load for the number of devices connected to the main network so it will have an impact on the quality of service. Device-to-Device (D2D) communication as components for LTE-A technology enabling a direct wireless link between the CUs without routing the data via the evolved Node B (eNB) signal or the core network. The need for algorithm and power control used to allocate radio resources so it can get a good quality of service because of communications technology D2D. In this study, we analyze and compare the performance parameters of D2D communication systems, including system interference, system sum-rate, system spectral efficiency, total energy system, and system energy efficiency based on Genetic and Greedy Algorithms in allocating radio resources and controlling the power of users. The genetic algorithm works with three operators in allocating resource block (RB), including proportional selection, crossover, and mutation. This process is repeated many times to produce several generations so that the best allocation can be got. The genetic algorithm has a flexible number of D2D and cellular communications in several RBs, minimum signal to interference plus noise ratio (SINR) also considered for mobile communication in ensuring the quality of its services. Numerical evaluations demonstrate the superior performance of the Genetic Algorithm in terms of system power, energy efficiency, and interference mitigation. As repetition gets larger, the Genetic algorithm results in better spectral efficiency

Energy efficient resources allocations for wireless communication systems

The energy consumption level of the telecommunication process has become a new consideration in resource management scheme. It is becoming a new parameter in the resource management scheme besides throughput, spectral efficiency, and fairness. This work proposes a power control scheme and user grouping method to keep the rational energy consumption level of the resource management scheme. Inverse water-filling power allocation is a power allocation scheme that optimizes the energy efficiency by giving the power to the user which have good channel conditions. The user grouping method becomes the solution for carrier aggregation (CA) scheme that prevents edge cell user get the resources from the high-frequency carrier. This can prevent energy wastage in the transmission process. This power control scheme and user grouping method can optimize the spectral and energy efficiency without increasing the time complexity of the system

Power control scheme using particle swarm optimization method in resource allocation process on D2D underlaying communication

Fast growing number of cellular telecommunication technology resulting on the increasing number of the user equipment. This condition increased the eNodeB load. To overcome this problem, the device-to-device (D2D) underlaying communication is introduced. In underlaying scheme, the D2D user equipment (DUE) will do the communication process using the same radio resources with the conventional cellular user equipment (CUE). To avoid a severe interference between these two types of user in the system, a good resource allocation is needed. In this work, a power control scheme using particle swarm optimization (PSO) is proposed, to manage the transmit power on each user on the system. The power control scheme take place after the greedy scheduling algorithm, after all user is given a resource block (RB) to do the communication process. The power transmit for each user is managed to reach a better system capacity, and to reduce the power consumed in one communication process. From the simulation, the PSO power control can improve the sumrate and spectral efficiency up to 12.97% and 3.38% respectively. The PSO power control also can reduce the power consumed by the system up to 8.84%. The fairness happens among the CUEs also can be maintained, despite of the decreasing fairness among DUEs

Konsep Transmisi Tidak Koheren menggunakan Differential Unitary Modulation pada OFDMA

ABSTRAKDifferential modulation adalah sebuah teknik modulasi yang memungkinkan pengiriman informasi tanpa diperlukannya estimasi kondisi kanal di sisi penerima. Teknik ini biasa diimplementasikan pada kondisi dimana kanal transmisi berubah dengan sangat cepat, seperti ketika pengguna layanan dalam kondisi mobilitas yang sangat cepat. Pada artikel ini, beberapa teknik differential modulation yang dikembangkan dari Space Time Block Code (STBC) diujicobakan pada Orthogonal Frequency Division Multiple Access (OFDMA) dengan dua skema yang berbeda. Skema pertama menggunakan konsep sistem antena multiple-input multipleoutput (MIMO), dan skema kedua adalah skema single-input single-output (SISO). Hasil pengujian yang diperoleh, teknik differential modulation dengan skema yang ditawarkan pada artikel ini mampu memberikan kinerja yang lebih baik daripada teknik differential modulation yang konvensional. Hasil riset menunjukkan konsep transmisi tidak koheren dapat menjadi solusi potensial untuk sistem komunikasi nirkabel berkecepatan tinggi.Kata kunci: transmisi tidak koheren, differential modulation, mobilitas tinggi, OFDMA, STBC ABSTRACTDifferential modulation is a modulation technique that can be used without the presence of channel estimation in the receiver. This technique is usually implemented when the channel condition changes rapidly, for example, when the user is in a high mobility condition. In this paper, several differential modulation techniques, which are modified from space-time block code (STBC) are tested for Orthogonal Frequency Division Multiple Access (OFDMA) using two different schemes. The first scheme uses multiple-input multiple-output (MIMO) antenna system, while the second scheme use single-input single-output (SISO). Based on our results, the differential modulation techniques proposed in this paper can overcome the conventional differential modulation technique. This research shows the proposed non-coherent transmission could be a potential scheme for high mobility wireless communications.Keywords: non-coherent transmission, differential modulation, high mobility, OFDMA, STBC