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Bandung District is one of crop provider for West Java Province. About 31.158,22 ha is used for crop. However, some of them are not maintained well due to lack of vegetation map information. Local authority has tried to map the vegetation in their area by using free license satellite images, and aerial images from Unmanned Aerial Vehicle (UAV). Despite both images being able to provide large plantation area images, both are unable to classify the vegetation type in those images. Telkom University with Bandung Agriculture Regional Office (Dinas Pertanian Kabupaten Bandung) has conducted joint research to develop algorithm based on 50-layer residual neural network (ResNet50) to classify the vegetation type. The input is of this algorithm is primarily aerial images are captured from different type, height, and position of crops. Seven different ResNet50 configurations have been set and simulated to classify the crop images. The result is the configuration with resized images, employing triangular policy of cyclic learning rate with rate 1.10−7 – 1.10−4 comes out as the best setup with more than 95% accuracy and relatively low loss.

Multiple Input Multiple Output (MIMO) is a key technology that plays an important role in achieving the 5G requirement due to its capability to increase channel capacity. However, the increase of channel capacity is influenced by several aspects such as mutual coupling. Many methods are done to decrease the mutual coupling effect such as polarization arrangement of the MIMO antennas. This study on the polarization arrangement of a circular patch MIMO antenna at 3.5 GHz was performed. Four elements of the MIMO antenna are arranged with several polarization configurations both in Co-Polarization and Cross-Polarization. Both simulation and measurement results showed that MIMO with Co-Polarization has a slightly wider bandwidth equal to 295.25 MHz compared to Cross-Polarization with a bandwidth of 274.63 MHz, due to better return loss performed by the former. However, from the mutual coupling perspective, it is observed that MIMO with Cross-Polarization can reduce the mutual coupling from -17.6676dB into -22.462 dB compared to Co-Polarization with the same element distance.

Sistem komunikasi generasi kelima (5G) menuntut kinerja yang lebih tinggi dari generasi sebelumnya. Sistem Massive Multiple Input Multiple Output (MIMO) muncul sebagai solusi untuk mengatasi generasi sebelumnya yang tidak dapat memenuhi permintaan data dalam jumlah besar. Penggunaan Massive MIMO ini memungkinkan diciptakannya multiple beam sehingga throughput dapat meningkat lebih besar daripada generasi sebelumnya. Sistem Base Station (BS) dengan banyak antena tidak dapat melayani pengguna dalam jumlah besar secara bersamaan. Maka dari itu sangat penting untuk memilih layanan pengguna yang akan dilayani secara bersamaan dan menentukan jumlah optimal pengguna yang akan dilayani. Penelitian ni mengusulkan algoritma pemilihan layanan pengguna untuk mencapai spektral efisiensi tinggi dan interferensi kecil. Algoritma yang diusulkan adalah Capacity-Based User Selection, Frobenius Norm-Based User Selection, dan Chordal Distance User Selection (CDUS) yang dikombinasikan dengan algoritma Round-Robin (RR). Berdasarkan simulasi yang telah dilakukan, algoritma pemilihan layanan pengguna yang dikombinasikan dengan algoritma RR memberikan kinerja yang baik dalam hal sumrate menggunakan algoritma Capacity-RR dengan nilai 673 bps/Hz, tingkat fairness pada algoritma CDUS-RR memiliki indeks fairness dengan nilai rata-rata 3,29, dan kompleksitas pada algoritma CDUS-RR memiliki rata-rata runtime sebesar 0,62 detik. Hasil penelitian ini diharapkan dapat berkontribusi dalam pengembangan penjadwalan pengguna pada Massive MIMO. Kata Kunci: : Massive MIMO, capacity-based user selection, frobenius norm-based user selection, chordal distance user selection, round-robin.

Digital broadband communications require a fast, functional and efficient system. In a digital communication system, a long sequence of bits '0' or '1' will inherits the loss of bit synchronization, and hence it can cause the false detection on the receiver. To avoid this, long sequence of bits will be randomized first so that long sequence of bits '0' or '1' can be removed. This randomization process is called scrambling and the circuit that works for the process is a scrambler. In the receiver there is a descrambler that serves to return the bits to their original information. This paper presents a design of scrambler and descrambler using a combination of Linear Feedback Shift Register (LFSR) with 15 registers, XOR logic gates, and Pseudo Random Binary Sequence (PRBS) generator structure with polynomial 1 + x14 + x15. One of the two main parts of LFSR is the shift register while the other is the feedback. In LFSR, the bits contained within the selected position in the shift register will be combined in a function and the result will be put back into this register's input bit. Feedback also makes the system more stable and no error occurrence. Then special tap is taken from a certain point in XOR and returned as a feedback register. The system is implemented on FPGA board Altera De0-Nano EP4CE22F17C6 Cyclone IV E. Resource memory required

Kapasitas kanal adalah parameter penting sistem komunikasi nirkabel. Suatu sistem komunikasi diharapkan mampu menyediakan kapasitas kanal yang tinggi. Sistem dengan Multipe Input Multiple Output (MIMO) antenna mampu menyediakan kapasitas kanal yang tinggi. Pada penelitian ini, kinerja sistem MIMO diamati dengan penerapan Scalable Orthogonal Frequency Division Multiple Access (SOFDMA). Teknik Adaptive Modulation and Coding (AMC) serta Adaptive MIMO Switching (AMS) juga diterapkan pada sistem ini. Jumlah subcarrier yang digunakan dalam SOFDMA tersebut yaitu 128 dan 2048. Kinerja sistem yang diamati yaitu kapasitas kanal dengan variasi kecepatan pengguna. Variasi pergerakan pengguna meliputi 0 km/jam dan 120 km/jam. Kapasitas kanal sistem dengan kombinasi teknik AMC dan AMS dapat mencapai 419,5115 Mbps saat kecepatan pengguna sebesar 0 km/jam. Saat kecepatan pengguna sebesar 120 km/jam, kapasitas kanal sistem dapat mencapai 23,9820 Mbps

Indoor Wi-Fi networks with 4G and 5G technology can work properly on wide coverage for high data rate services. Existing Wi-Fi devices need to implement Multiple-Input Multiple-Output (MIMO) antenna technology to provide high data rate. However, the antenna bandwidth and gain are relatively small. On previous research, the MIMO antennas with Resonator and Interdigital Capacitor have wide bandwidth, but gain of the antennas is low. In previous research, Complementary Split Ring Resonator (CSRR) on MIMO antennas provides high gain but the bandwidth decreases. This paper proposes an 2x2 MIMO monopole antenna design at 2.4 GHz for indoor Wi-Fi that implementing two combined methods, i.e., Resonator-Interdigital Capacitor with CSRR to improve the antenna performances. The idea is the addition of Resonators and Interdigital Capacitors is to increase the bandwidth, while CSRR is added to increase gain. The results show the proposed antenna has better return loss and decoupling values of 0.323 dB and 2.359 dB, respectively. The bandwidth and gain of the proposed antenna increase by 73.7 MHz and 0.361 dB, respectively when compared to Resonator Interdigital Capacitor MIMO antenna. The proposed antenna has return loss of −17.784 dB and decoupling value of −12.871 dB at 2.4 GHz, with the bandwidth of 644.3 MHz and gain of 1.996 dB.

In accordance with the scenario of ITU-R,IMT-2020 or fifth generation (5G) will have 3 scenarios, one of which is Enhanced Mobile Broadband (eMBB). Multi antenna by applying massive MIMO is used on eMBB. Frequency candidates used in the fifth generation (5G) are sub-6 GHz and sub-28 GHz frequencies. This paper focuses on simulating massive MIMO antenna designs that work at 3.5 GHz and 26 GHz frequencies. The antenna is arranged by rectangular patch in the form of an array with 12 patches for the 3.5 GHz frequency and 96 patches for the 26 GHz frequency, so the number of patches on the antenna is 108 patches. The designed antenna will be used as an indoor transmitter antenna. The antenna uses a proximity coupled feed with connectors and dielectric constants 2.2. The designed antenna gets s-parameter result of less than −10.8199 dB, a gain greater than 7.3 dB, and a mutual coupling of less than −32,6201 dB.

Concurrent illumination and communication using LED for Visible Light Communication (VLC) system has been the focus of some researches in the past years. Giving a new purpose of old technology, without addition of a new infrastructure becoming a strong point for VLC system. In this research we used diversity technique to perform a data communication using visible light medium. With diversity order of 3 with red Light Emitting Diode (LED), Green LED, and Blue LED. Each carry a redundant data. We encode the data and its redundant in a repetition code. Simulation results shows system performance with BER of $2.41\mathrm{x}10^{-4}$ at SNR of 1 dB compared to the proposed system with shadowing effect with BER of $-2.47\mathrm{x}10^{-4}$ at SNR of 1 dB. This show that the system is robust against shadowing in an indoor VLC environment.

Massive Multiple Input Multiple Output (MIMO) and Full Duplex Single Channel (FDSC) at mm-Wave are key technology of future advanced wireless communications. Self-interference is the main problem in this technique because big number of antennas. This paper proposes dual-cross-polarized configuration to reduce self-interference between antennas. We conduct some computer simulations to design the antenna and to verify self-interference effect of the designed antenna. Computer simulation shows that the proposed design has lower Envelope Correlation Coefficient (ECC). This result is achieved because dual-cross-polarized technique can reduce coupling between an-tennas. We found that bit-error-rate (BER) performances of the proposed antenna is better than single polarized antenna indicating that the designed antenna is well design to reduce self-interference effect between antennas.

This paper proposes Telkom University 5G channel model under foliage effect. The channel model is obtained from series of computer simulations by considering operating frequency of 3.3 GHz, bandwidth of 40 MHz, and real-field parameters of Telkom University environments. We also present the performances evaluation including the outage performance evaluated under Telkom University 5G channel model with and without foliage effects. The bit error rate (BER) and block error rate (BLER) curve of cyclic-prefix orthogonal frequency division multiplexing (CP-OFDM) numerology zero with 5G New Radio (NR) complex-binary phase shift keying (C-BPSK) and Polar codes are presented in this paper to validate the outage performance of Telkom University 5G channel model. We found that the Telkom University 5G channel model has 16 paths for the case of model without foliage effect and has 8 paths for the case when foliage effect is taken into account. The results show that foliage attenuation causes performance degradations indicated by worse outage performance and smaller number of paths at 3.3 GHz frequency. The obtained outage performance from the proposed Telkom University 5G channel model is expected to be a reference for 5G system implementation in Telkom University and Indonesia such that an optimal 5G system implementation in Telkom University and Indonesia can be achieved.

Increasing data rate and high performance is the target focus of wireless communication. The multi carrier on multi-hop communication system using relay's diversity technique which is supported by a reliable coding is a system that may give high performance. This research is developing a model of multi user and two scheme of multi carrier CDMA on multi hop communication system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality signal at the receiver in the Rayleigh fading channel and the noisy system. In this research, MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi carrier CDMA on multi hop wireless communication system (relay diversity) which is able to improve the received signal performance. MC DS CDMA on multi hop wireless communication system with 2 hops is better performing than MC CDMA on multi user without Multi User Detector. To reach BER 10-3 multi hop system with MC CDMA needs more power 5 dB than MC DS CDMA at 5 users using Alamouti scheme for symbol transmission at the relay.

The D2D communication is expected to improve devices’ energy-efficiency, which has become a major requirement of the future wireless network. Before the D2D communication can be performed, the device discovery between devices must be done. The previous works usually only assumed one mode of device discovery, i.e. either use network-assisted (with network supervision) or independent (without network supervision) device. Therefore, we propose a selective device discovery for device-to-device (D2D) communication that can utilize both device discovery modes and maintain devices’ energyefficiency. Different from previous works, our proposed method selects the best device discovery mode to get the best energy-efficiency. Moreover, to further improve the energy-efficiency, our proposed method also deployed in D2D cluster with multiple cluster heads. The proposed method selects the most suitable mode using thresholds (cluster energy consumption and new device acceptance) and cluster energy expectation. Our experiment result indicates that the proposed method provides lowest energy consumption per new accepted device while compared with schemes with full network-assisted and independent device discovery in low numbers of new device arrival (for the number of new devices arrival = 1 ~ 3).

In this paper we present a research testbed for spectrum sensing in cognitive radio systems. We consider spectrum sensing based on Eigen values of sample covariance matrix of the input signal. When considering the hardware implementation of the algorithm, it will pose a question on how to calculate the Eigen values with low complexity. In practice, there is a tradeoff between complexity and detection performance. In theory, the Eigen values of the sample covariance matrix can be found by using a Discrete Fourier Transform (DFT), which can be easily implemented in hardware using Fast Fourier Transform (FFT). Simulations are performed in MATLAB and real-time measurements carried out in Xilinx Kintex-7 Field Programmable Gate Array (FPGA). The result shows that the probability of detection increases as the Signal to Noise Ratio (SNR) increases. The result from hardware shows a less performance compared to the simulation, that is because the threshold is being calculated from equation(5) and not obtained from the distribution of the received signal under hypothesis 0. In terms of the computational complexity, the Eigen values method which proposed in [6], is about M times that of the Number of samples Ns, where M is the autocorrelation length of the received signal. However our proposed method only needs 2∗M LUT(Look Up Tables) from the hardware resources as shown in table 3. The simulations and implementation show that the proposed method works well with low complexity, without using prior information of the primary user's signal, the channel and noise power compared to the current spectrum sensing state of the art.

Device-to-device (D2D) communication not only expected to leverage the energy efficiency in the devices side but also on the network side. The previous works usually only address the energy efficiency of device discovery, which is an important process in D2D, in device side. In this work, we addressed the energy-efficiency of a network element during D2D device discovery. First, we adapted energy calculation for base station energy efficiency in independent device discovery. Second, we also adapted energy calculation for base station energy efficiency in network-assisted device discovery. Third, we conducted simulation to examine base station energy efficiency in both cases. Our simulation result shows that base station energy efficiency can be maximized by utilizing independent device discovery with multiple CHs in a cluster.

In this paper, we propose the usage of Unmanned Aerial Vehicle (UAV) as a flying mobile base tower station for discovering Device-to-Device (D2D) devices in the disaster area. In a disaster area, energy consumption of both devices and network become an important constraint. Therefore, there is a need to establish wireless network communication in large area rapidly under the condition of infrastructure failure. The previous works does not calculate the energy consumption of the UAV and consider the use cases of UAV flight path for specific disaster condition, e.g. flood, earthquake, etc. The objective of this paper is to provide UAV flying paths that can adapt according to disaster condition which satisfy the UAV energy constraint. We enhance four schemes for the UAV flying paths: O-path, Rectangular path, ZigZag-path, and S-path. This enhancement reduces the flight path gap area and lead the increasing of covered area. To examine the best UAV flight path for certain disaster cases, several simulations were performed and discussed. The results show that for distributed damage pattern, the optimum UAV flying pattern is an S - path because of its large coverage area (covering around 80 percent of total devices in altitude 100 m). Otherwise, for centralized damage pattern, the optimum UAV flying patterns are O, Rectangular, and Zigzag path because of its short flight duration and less energy consumption (eight times smaller than the S - path in altitude 100 m).

Massive MIMO technology can increase capacity, data rate, and link reliability significantly without additional bandwidth or transmission power. Most of the previous study on Massive MIMO systems are using low frequency (2.6 GHz). This frequency is not suitable for future broadband technology, because IoT devices will use high frequency and possible cell coverage would be smaller. This work proposes Massive MIMO transceiver antenna that can be implemented in high frequency (60 GHz). This system provides broadband wireless communication which gives high capacity, high data rate and wide bandwidth. In this works the number of antennas is 64×64. Antennas can be set adaptively to capacity. In this case all of the antennas as a receiver are functioned to get redundancies and 32 antennas as transmitter adjusted to the required capacity. Configuration of antenna has been set to eliminate the mutual coupling effect. The system utilizes full duplex single channel (FDSC) which use the same frequency and time to transmit and receive data. In FDSC, bandwidth can be minimized, but self interference effect appeared and disturbing the system performance of Massive MIMO. The effect of self interference for Massive MIMO transceiver antenna simulated from 10% to 100%. The proposed system provides the channel capacity ≈ 390 bits/s/Hz or ≈ 39× spectral efficiency of SISO system. The simulation result shows that mutual coupling effect ≈ 0. The Massive MIMO have a tolerance of 20% self interference effect, however it could decrease 20% channel capacity as well.

Millimeter-wave (mm-Wave) Massive Multiple Input Multiple Output (MIMO) at 60 GHz is a candidate of advanced wireless communications for indoor environment. Mm-Wave massive MIMO antenna with lower frequency with sectoring technique has been proposed in previous research. Also dual polarized configuration for MIMO in lower frequency and lower number of antenna. Massive MIMO at 60 GHz mm-Wave is not evaluated yet in these previous research. In this paper, dual polarized mm-Wave massive MIMO has been proposed. Antennas are modeled in circular disk proximity coupled planar array. Bandwidth of dual polarized configuration is 4.349 GHz, wider than 4.303 GHz in single polarized configuration. Envelope Correlation Coefficient (ECC) of dual polarized configuration is 25 times lower compared to single polarized configuration. Dual polarized configuration shows better performance both in bandwidth and ECC compared to single polarized configuration.

In the uplink system, different carrier frequency offsets (CFO) of different users at the receiver resulting multiuser interference (MUI) and thus degrade the performance of Multicarrier Code Division Multiple Access (MC-CDMA) system. In the previous study, Modified Minimum Mean Square Error Frequency Domain Equalization (Modified MMSE-FDE) has been proposed by Agnihotri which results in a better performance than the conventional MMSE. However, the achieved Bit Error Rate (BER) is not smaller than 10−2 for Signal to Noise Ratio (SNR) below 20. This paper proposed a new algorithm to improve Modified MMSE-FDE performance in mitigating multiuser interference (MUI) in single cell MC-CDMA system, that is called as Carrier Frequency Offset Estimation-Minimum Mean Square Error Frequency Domain Equalization (CFO Estimation-MMSE FEQ). CFO Estimation-MMSE FEQ takes into account the rest of MUI as well as Modified MMSE-FDE to design equalization coefficient, but CFO Estimation-MMSE FEQ uses CFO estimation that is not on Modified MMSE-FDE. The value of CFO is estimated and regenerated in the receiver and then used to estimate MUI. In order to get signal processing more efficient, CFO Estimation-MMSE FEQ only takes the real trace of equalization coefficient matrix. MC-CDMA with CFO Estimation-MMSE FEQ has better performance than MC-CDMA with Modified MMSE-FDE. However, the complexity of CFO Estimation-MMSE FEQ is higher than Modified MMSE-FDE. By taking only the real trace of equalization coefficient matrix, the complexity of CFO Estimation-MMSE FEQ is getting simpler than taking the whole of equalization coefficient matrix. Furthermore, CFO Estimation-MMSE FEQ that takes only the real trace of equalization coefficient matrix is 2.9 % more efficient than CFO Estimation-MMSE FEQ that takes the whole of equalization coefficient matrix.

The performance of communications is determined by the channel, therefore knowledge of channel model of a country is important. This paper proposes (i) the fifth telecommunication generation (5G) Indonesia channel model and (ii) a framework to derive the channel model of any locations in Indonesia. We consider operating frequency of 3.3 GHz with bandwidth of 40 MHz with real-field parameters of several cities in Indonesia. We also present a theoretical outage performance evaluated for the proposed Indonesia 5G channel model validated by block error rate (BLER) performances of cyclic-prefix orthogonal frequency division multiplexing (CP-OFDM) numerology zero with 5G complex binary phase shift keying (C-BPSK) and Polar coding scheme. Sub-optimal Polar codes are used in this research, where better performances are expected in the future. We found that the Indonesia 5G channel model has 17 paths for the case of without foliage effect and has less than 15 paths for the case of with foliage effect. The results show that foliage attenuation causes performance degradations indicated by smaller number of paths and worse theoretical outage performances. The obtained outage performances from the proposed Indonesia 5G channel model in this paper are expected to be a reference for 5G implementations in Indonesia. Abstrak Kinerja sistem komunikasi ditentukan oleh kanal, sehingga pengetahuan model kanal suatu negara menjadi penting. Makalah ini mengusulkan (i) model kanal telekomunikasi generasi ke-lima (5G) Indonesia dan (ii) kerangka kerja untuk menghitung model kanal di lokasi lain di Indonesia. Model kanal dalam makalah ini diciptakan untuk bandwidth 40 MHz pada frekuensi 3,3 GHz dengan parameter riil lapangan. Makalah ini juga menampilkan teori outage performance yang diperoleh dari model kanal 5G Indonesia, kemudian memvalidasi teori outage performance tersebut menggunakan block error rate (BLER) pada cyclic-prefix orthogonal frequency division multiplexing (CP-OFDM) numerology zero dengan complex binary phase shift keying (C-BPSK) standard 5G dan Polar coding. Semua hasil numerik diperoleh dari simulasi komputer menggunakan parameter riil lapangan untuk alam Indonesia. Makalah ini menemukan bahwa kanal 5G Indonesia dapat dimodelkan power delay profile (PDP) dengan 17 path untuk kanal tanpa efek dedaunan dan kurang dari 15 path untuk kanal dengan dedaunan. Hasil tersebut menunjukkan bahwa redaman daun menyebabkan penurunan kinerja, yang ditandai dengan penurunan jumlah path dan memburuknya outage performance. Kurva outage performance yang diperoleh dari model kanal 5G Indonesia diharapkan menjadi referensi untuk implementasi sistem 5G di Indonesia dalam pengembangan 5G di Indonesia secara optimal, terutama untuk lokasi yang memiliki dedaunan lebat.

Teknologi 5G adalah sebuah fase selanjutnya dari teknologi 4G. Kandidat frekuensi yang akandigunakan pada teknologi 5G berada pada spektrum gelombang milimeter. Salah satu teknologi yangmendukung 5G adalah MIMO. Internet of Things(IoT) sebagai bagian dari teknologi 5G perludikembangkan di Indonesia khususnya untuk mendukung komunikasi indoor sekaligus outdoor. Salahsatu spektrum frekuensi 5G adalah 28 GHz. Pada penelitian sebelumnya, terdapat desain compact arraymassive MIMO dual-band antena dengan menggunakan patch cross dan persegi tetapi berada padafrekuensi 5,4 GHz dan 15 GHz. Pada penelitian ini dirancang antena MIMO mikrostrip yang bekerjapada frekuensi 6 GHz dan 28 GHz dengan masing-masing frekuensi memiliki patch dan dimensi yangberbeda. Antena dirancang dengan menggunakan metode compact MIMO tetapi dengan desain yangsedikit berbeda dan hanya menggunakan patch persegi saja. Antena memiliki pola radiasi unidireksional,polarisasi linear, dan teknik pencatuannya adalah proximity coupled serta cross polarization. Hasil dariperancangan yang dilakukan, didapatkan antena MIMO dual-band di 6 GHz dan 28 GHz dengan nilaiparameter S11 terbesar -17,7 dB, gain terkecil sebesar 4,86 dBi, dan bandwidth 870 MHz untuk frekuensi28 GHz dan 60,2 MHz untuk frekuensi 6 GHz. Setelah dilakukan perancangan, selanjutnya dilakukananalisis terhadap parameter gain, pola radiasi, koefisien korelasi, dan mutual coupling.

Sistem komunikasi selular selain dapat digunakan sebagai alat komunikasi suara juga untuk komunikasi data. Salah satu penerapan sistem komunikasi data tersebut adalah sistem CDPD ( Cellular Digital Packet Data ) yang dibuat overlay pada sistem komunikasi selular analog, yaitu AMPS. Sistem tersebut menjadi fokus pada penelitian ini, yang melakukan simulasi secara teoritis mengenai kinerja sistem komunikasi data tersebut, yaitu meliputi pengaruh penerapan sistem ini terhadap pemakai komunikasi suara, throughput, delay rata-rata dan rugi-rugi trafik suara ternormalisasi terhadap rugi-rugi trafik tanpa penerapan CDPD. Ada 2 macam algoritma distribusi kanal yang diterapkan pada sistem CDPD ini, yaitu algoritma dedicated channel dan algoritma frequency hopping . Dari hasil simulasi terlihat bahwa penerapan sistem ini dengan algoritma dedicated channel akan mengurangi jumlah kanal yang melayani trafik suara, sehingga P block dari trafik suara akan naik. Penggunaan antena omnidirectional memberikan pengaruh lebih baik terhadap kualitas trafik suara dari pada penggunaan antena sektor. Sedangkan dengan algoritma frequency hopping, terlihat bahwa karena sistem ini memanfaatkan kanal yang tidak digunakan oleh trafik suara, dan kanal yang digunakan oleh sistem ini dianggap kosong oleh trafik suara, maka penerapan sistem ini akan menaikkan penggunakan kanal sistem selular, sehingga menurunkan C/I. Penggunaan antena sektor akan menyebabkan kinerja sistem CDPD lebih baik dari pada penggunaan antena omnidirectional, tetapi akan menyebabkan rugi-rugi trafik suara ternormalisasi yang lebih buruk dari pada penggunaan antena sektor.

Data consumption increased sharply, all triple play services such as Voice, Data-Internet & Video can be performed on one communication path, even fiber optic has also bandwidth limitations, previous studies tried to maintain the fairness among the users, but there is no fairness of service therefore the allocation of data transmission must be optimized as their needs. A Passive Optical Communication in downstream direction are presented. We proposed to modify current burst methods to scheduling distribution SC on system OFDM from OLT to ONU by utilize FDMA to allocating SubCarrier based on the services are applied. Significant gain of bandwidth efficiency up to 60% obtained when link is being congest.

Multi Carrier Code Division Multiple Access (MC-CDMA) has become options for high data rate systems in high mobility without reducing the interference robustness. Discrete Fourier Transform (DFT) MC-CDMA still has usual problem of Multi Carrier Modulation (MCM) that is high Peak to Average Power Ratio (PAPR), but this problem can be reduced by replacing fourier transform with wavelet transform. This paper will analyze the result of Discrete Wavelet Transform (DWT) MC-CDMA compared with DFT MC-CDMA. The simulation results showed that DWT MC-CDMA system has better quality than DFT MC-CDMA but DWT MC-CDMA has higher complexity than DFT MC-CDMA.

This paper presents finite-length performance analysis for wireless super-dense networks comprising two multiway relays (SDN-2MWR) to support full data-exchange among massive number of users/devices over Rayleigh fading channels. In practice, finite-length analysis is important since the networks should serve users/devices with low latency indicated by short number of time-slots. Due to the nature of massive number of users/devices, where scheduling over massive number of users (usually in hundred or thousand) is difficult, we exploit random access with a capability of error correction resembling low density parity check (LDPC) codes. In this paper, we show that the dynamic of Rayleigh fading is even beneficial to generate two independent graphs captured by the first and the second relay without requiring all users send messages independently to each relay. Independent graphs are essential in SDN-2MWR to ensure the probability of successful decoding as high as possible and to significantly reduce error-floor in finite-length setting. Based on the theoretical network capacity bound indicating the maximum achievable traffic supported by the networks, we found that for SDN-2MWR a significant gain closer to the bound with lower packet-loss-rate (compared to the dense network with a single relay) is achievable without assuming ideal independent graph even with simple degree distributions without irregularity.

In this paper, utilizing user-order chunk allocation algorithm for OFDMA systems using carrier aggregation environment is proposed and evaluated. Chunk allocation algorithm is performed based on mean greedy algorithm which has low complexity. In order to adopt this algorithm to those system, all users are divided into a certain group in accordance with the number of available aggregated carriers. The simulation results are shown that the performance and time complexity of the proposed scheme is same with the system without user grouping. Therefore, the proposed scheme could be considered to realize in LTE-Advanced platform.

Improvement of information technology especially in telecommunication system support wireless communication system must provide high data rate service. OFDM is the system that have high data rate and had been used as the method to overcome multiple channel effect But the weakness of OFDM system is PAPR. Large PAPR causes non linear distortion of signal and non orthogonal of sub carrier that caused performance of OFDM system will decrease. Recently, it has been developed a system as an alternative to OFDM system called OWDM (Orthogonal wavelet division multiplex). Basic idea of OWDM is replaced Inverse Discrete Fourier Transform (IDFT) with the Inverse Discrete Wavelet Transform (IDWT) for generating orthogonal sub-carrier. Like IDFT on OFDM systems, function of IDWT on OWDM system is modulator, while demodulator process used DFT (Discrete Fourier Transform) on OFDM and DWT (Discrete Wavelet Transform) on OWDM. This paper will compare the performance between OWDM and OFDM system on fading Rayleigh channel. Simulation both of system resulted same performance on multipath Rayleigh fading channel but different PAPR value PAPR of OWDM system is smaller than OFDM system. Thus OWDM techniques can be chosen as an alternative method to overcome the problems of the high PAPR value in OFDM techniques.

LTE-Advanced and Femtocell are deployed by cellular operators to improve the coverage and capacity to respond the demand for higher data rates in wireless networks. Integration of femtocell into cellular network faced interference between femtocell and macrocell. Several scenarios based on Fractional Frequency Reuse (FFR) methods have been proposed to mitigate this interference, including integer fractional fraction reuse (FFR), soft frequency reuse (SFR), frequency frequency reuse orde-3 (FFR-3) and optimal static fractional frequency reuse (OSFFR). The study proposes Distributed Fractional Frequency Reuse scenario to mitigate interference and improve performance simultaneously. Distributed fractional Frequency reuse (DFFR) is an improvement of OSFFR by allocating sub-bands proportional and it is reused for each sector.

The most up-to-date application and many numbers of users need higher access speeds and lower latency of wireless communication. As a result, mobile companies need more capacity and higher efficiency to give the high quality service to the customers. LTE has been designed to get broader channels up to 20MHz, with low latency and packet optimized radio access technology. The peak data rate envisaged for LTE is 100 Mbps in downlink and 50 Mbps in the uplink. To support the simultaneous use of legacy and new systems, mobile companies need to give a better radio system, especially in central Phnom Penh city of Cambodia. The purpose of this study aims to designs, simulates, analyzes and expose the state of the art of map planning LTE radio system. Special focus is laid on radio link budget along with broad coverage area and capacity. The outcomes cover the interference limited coverage calculation, the traffic capacity calculation and radio frequency assignment. The implementation is attained on the software platform for the LTE Radio Planning and also can see the simulation antenna in Google Earth. The study will show a detailed LTE radio dimensioning procedure such as coverage area and capacity in Phnom Penh city. The simulation and analysis of the coverage by signal level and overlapping zone also a part of this work.

Rapid development of Broadband Wireless Access (BWA) requires improvement of system capacity. MU-MIMO is considered as a benefit solution as its ability to enhance the system capacity without additional bandwidth. However, the implementation of MU-MIMO creates interference problem that is Multi User Interference (MUI). Thus in order to suppress the MUI, precoding technique is needed before the signal is transmitted. Linear precoding is suitable to be implemented due to its low complexity yet it has lower capacity than non-linear. One of linear precoding methods is Block Diagonalization (BD) which has flexible configurations so, the capacity can be increased. In purpose to obtain performance enhancement of BD, this study focuses on improving performance and finding the best configuration of BD for BER performance. The research accomplished by analyzing the effect of the change of numbers between transmitting and receiving antenna; and analyzing performance of BD towards different channel response. The result of this research is the performance improvement of BD is in line with adding the number of received antennas on user and reducing the number of transmitting antennas. In addition, better performance can be achieved by implementing BD in lower LOS factor. Therefore, performance of BD in i.i.d Rayleigh is better than Rician channel. By using BD {1,1}×2 configuration, the best performance of BD can be achieved.

It will be diffcult to use either omnidirectional or fixed beam antenna due to the high propagation losses caused by atmospheric absorption at mmWave for 5G mobile communication. Several studies have been conducted recently using butler matrix which is part of switchable antenna with some advantages such as simple, minimal cost, low loss, etc. Previous studies also have designed vivaldi array antenna at 28 GHz which provides a fix beam directional radiation pattern with narrow beam that requires real phase setting. However, there has been no research using vivaldi antenna with butler matrix, whereas it has some advantages such as wide bandwidth, high gain, high directivity, etc. This paper proposed 4x4 butler matrix integrated with vivaldi antenna by using phase shift of 45 . The design is developed on a single layer of Rogers RT5880 with dielectric constant 2.2 and thickness 0.254 mm. Best results of simulation were picked for overall system at 28 GHz, and the results of antenna as follows: the return loss was below -10 dB, the realized antennas gain was 10.2 dB with unidirectional radiation pattern and bandwidth antenna of 6 GHz that covers from 25 GHz to 31 GHz. The butler matrix average phase di erent between output port are -44.106°, 137.38°, -137.66°, 43.95° with phase err°r °f 0.894°, 2.38°, 2.66°, 1.06°. Antenna array that has been given di erent phase by butler matrix is able to shift radiation pattern on the input port successively with range of beam that can be achieved equal to 185o.

Massive MIMO with multiple BS antennas can give simultaneous service for multiple user equipments (UEs) that are widely considered in massive connectivity to meet high data rate requirements. User selection is critical to optimize the overall performance of MIMO systems in various scenarios and has been extensively studied in cellular networks to guarantee service for users. In the previous study, location-dependent user selection (LUS) had extremely low computational complexity which is capable to enhance sum rate performance, but there are many environmental condition assumptions that make this algorithm does not reflect real conditions. In this research, we proposed modified LUS with approximations of sum rate in large system regimes by adding the sum ergodic of the distance from one user to another which enhance sum rate performance. In addition, we vary the user environment that was ignored in previous research by varying the path loss exponent values. In this research, we focus modify on sub-urban areas with each UEs having different environmental conditions. The selection scheme is equipped with spatial correlation fading on the transmitter side MIMO antenna. The simulation shows an increase in sum rate between 0.0012 to 0.3935 in perfect CSI. For the imperfect CSI with antenna correlation coefficient for power at 30 dBm is 0.5 when 32x64 antennas is 14 optimal active UEs with sum rate is 23.4207 bps/Hz. For cases where the user is located in different positions with different environmental circumstances, with 32x64 antennas showing the highest sum rate is 24.8436 bps/Hz with 17 optimal UEs.

Wireless communication now has been focus to increase data rate and high performance. The multi carrier on multi-hop communication system using relay's diversity technique which is supported by a reliable coding is a system that may give high performance. This research is developing a model of multi carrier CDMA on multi hop communication system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality signal at the receiver in the Rayleigh fading channel and the noisy system. In this research, MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi carrier CDMA on multi hop wireless communication system (relay diversity) which is able to reduce the complexity of the system but the system performance even can be maintained and improved. MC CDMA on multi hop wireless communication system with 2 hops is performing much better than Single Input Single Output (SISO) system (1 hop system). Power needed for 1 hop system to have the same quality as 2 hops system to reach BER 10 -3 is 12 dB. And multi hop system needs orthogonal symbol to send from relay than original symbol to reach better performance. 12.5 dB power up is needed for multi hop system which sent same symbol as transmitter than relay system which sent orthogonal symbol.

Alteration of user's speed and direction to the base station cause Carrier Frequency Offset (CFO). CFO is able to damage orthogonality among subcarriers and decrease system performance significantly. There are several researches already focused on ICI mitigation, however most of them only employed restricted inputs for CFO in order to generate Inter Carrier Interference (ICI). This research proposes modified dynamic CFO resulted from Doppler shift and oscillator accuracy tolerance. The CFO value takes user's velocity and random user's direction as well as involving oscillator instability. The main purpose of this research is to reduce CFO in dynamic propagation nature in various users' velocities using Extended Kalman Filter (EKF) method. The result showed that those dynamic CFO values can be reduced using EKF method and thereby enhance OFDM system performance, in this case Mobile WiMAX 802.16e. Besides, this proposed system has the adaptability upon different CFO values by adjusting better improvement for higher speed and worse oscillator's quality.