A Combined User-order and Chunk-order Algorithm to Minimize The Average BER for Chunk Allocation in SC-FDMA Systems

A Chunk by chunk-based allocation is an emerging subcarrier allocation in Single Carrier Frequency Division Multiple Access (SC-FDMA) due to its low complexity. In this paper, a combined user-order  and chunk-order allocation for solving chunk allocation problem which minimizes the average BER of all users while improving the throughput in SC-FDMA uplink is proposed. The subcarrier grouping into a chunk of all users on both-order allocations are performed by averaging the BER of a contiguous subcarriers within a chunk. The sequence of allocation is according to the average of users’ BER on user-order allocation and the average of chunks’ BER on chunk-order allocation. The best allocation is determined by choosing one of both-order allocations which provides the smaller BER systems. The simulation results showed that the proposed algorithm can outperform the previous algorithms in term of  average BER and throughput without increase the time complexity.

Implementation of ICI Self Cancellation In User's Velocity From 0 to 700 Km/h to Mitigate Inter-Carrier Interference

The effect of Inter-Carrier Interference (ICI) makes Orthogonal Frequency Division Multiplexing’s (OFDM’s) performance getting worst. ICI itself can be caused by 2 causes, miss synchronization at transceiver and Doppler phenomenon. But Doppler phenomenon takes the highest responsibility for increasing the value of Carrier Frequency Offset (CFO). Doppler phenomenon is closely related to the movement or velocity of the user. The higher the velocity, the higher the value of CFO. In this paper, we evaluate ICI Self Cancellation method to reduce the impact of ICI while the increasing of the user’s velocity. The simulation results show that the application of ICI Self Cancellation in iterated velocity from 0 to 700 km/h gives BER’s correctio

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

Radio Resource Allocation with The Fairness Metric for Low Density Signature OFDM in Underlay Cognitive Radio Networks

Low density signature orthogonal frequency division multiplexing (LDS-OFDM), one type of non-orthogonal multiple access (NOMA), is a special case of multi-carrier code division multiple access (MC-CDMA). In LDS-OFDM, each user is allowed to spread its symbols in a small set of subcarriers, and there is only a small group of users that are permitted to share the same subcarrier. In this paper, we study the resource allocation for LDS-OFDM as the multiple access model in cognitive radio networks. In our scheme, SUs are allocated to certain d v subcarriers based on minimum interference or higher SINR in each subcarrier. To overcome the problem where SUs were allocated less than the d v subcarriers, we propose interference limit-based resource allocation with the fairness metric (ILRA-FM). Simulation results show that, compared to the ILRA algorithm, the ILRA-FM algorithm has a lower outage probability and higher fairness metric value and also a higher throughput fairness index

Konfigurasi Optimum pada Susunan Linear Antena MIMO Mikrostrip Polarisasi Sirkular

ABSTRAK Untuk memastikan sistem antena MIMO memiliki kapasitas kanal yang diharapkan, maka rancangan antenanya harus memenuhi indikator kinerja optimum, yang ditentukan oleh karakteristik dari elemen penyusun dan konfigurasi susunan antena MIMO. Polarisasi antena merupakan aspek yang mempengaruhi mutual coupling antar elemen antena pada MIMO. Sebagai salah satu parameter penting, maka konfigurasi polarisasi elemen antena pada proses desain harus dikaji dengan baik. Pada paper ini sebagai kontribusi penelitian, dilakukan kajian secara mendalam mengenai susunan linear elemen mikrostrip dengan polarisasi sirkular untuk antena MIMO pada frekuensi sub-6 GHz. Hasil penelitian menunjukkan bahwa konfigurasi B dan C yang merupakan konfigurasi polarisasi silang yang memiliki rentang frekuensi 2,04 x dan 2,08 x lebih lebar dibandingkan konfigurasi A, yang memiliki rentang frekuensi terendah berdasarkan Envelope Cross Correlation (ECC), dan memiliki rentang frekuensi 3,9 x dan 3,87 x lebih lebar dibandingkan konfigurasi E yang memiliki rentang frekuensi terendah berdasarkan Diversity Gain (DG). Kata kunci: MIMO, antena, polarisasi sirkular, konfigurasi.   ABSTRACT To ensure MIMO antenna system has the expected channel capacity, antenna design needs to meet the requirement of MIMO antenna optimal performance indicators, that are determined by the characteristics of the constituent elements and the configuration of the MIMO antenna array. Antenna polarization is a feature that affects the mutual coupling between antenna elements in MIMO. Therefore, the configuration of antenna element polarization in the design process needs to be well studied. Our research contribution in this paper is an in-depth study of the linear arrangement of circularly polarized microstrip elements for MIMO antennas at sub-6 GHz frequencies. The simulation results show that B and C configuration as cross-polarizing configuration have 2,04 x and 2,08 x wider bandwidth than A configuration, that has narrowest bandwidth based on Envelope Cross Correlation (ECC), and have 3,9 x and 3,87 x wider bandwidth than E configuration, that having narrowest bandwidth based on Diversity Gain (DG). Keywords: MIMO, antenna, circular polarization, configuration