A Comparative Study of 4G and VoLTE

This research paper provides an insight into the comparison between VoLTE and 4G. 4G Wireless Systems or Fourth generation wireless system is a packet switched wireless system with wide area coverage and high throughput. It is designed to be cost effective and to provide high spectral efficiency. VoLTE (voice over LTE) supports voice calls over 4G LTE network. With advanced VoLTE technology, the 4G network now provides high-speed data services, high-quality voice and video calls at affordable price. This paper first presents the challenges and benefits of both 4G and VoLTE and then compares them with consideration of different points. Keywords: GSM, LTE, VoLTE, 3G, HSPA, RAN

Channel Statistical OFDM Transmission System Resource Allocation Algorithm

In order to achieve high spectral efficiency in OFDM transmission system, it is necessary to put forward the corresponding efficient subcarrier and power allocation algorithm. Therefore, on the basis of understanding the basic principle and system structure of OFDM, this paper analyzes the corresponding allocation algorithm according to the multi-user water injection theory, and studies the final results, so as to provide an effective scientific basis for future channel statistics research.

Hardware Phase Shift Hybrid Precoding Designs For Multi-User Massive MIMO Systems

Hybrid precoding is a challenging design for massive MIMO systems that involves a combination of analog and digital processing, aiming to maximize the spectral efficiency (SE). Most works on hybrid precoding focus on the single phase shifter (SPS) implementation to adapt the phase from RF chains to antennas. In this paper we propose to develop the double phase shifter (DPS) and the fixed phase shifter (FPS) in both single-path and multi-path configuration. Simulation results certify a significant improvement for both proposed implementations with high hardware efficiency (HE) and high spectral efficiency especially in multi-path environment.

SCMA-MIMO system with adaptation to the channel state

Sparse code multiple access (SCMA) is one of the promising implementations of non-orthogonal multiple access (NOMA) methods. SCMA provides high spectral efficiency and a large number of network resources. We describe a communication system with SCMA, space-time block coding (STBC), multiple input multiple output (MIMO) technology, and orthogonal frequency division multiplexing (OFDM). The architecture of such systems, including algorithms of formation and processing of signals is considered. A method for adapting signals to the state of the spatial channel transmission based on information about the matrix of channel coefficients is proposed. The application of such adaptation allows to compensate the influence of the channel and to reduce the probability of bit errors. We consider the bit error rate (BER) performance of the communication system in different channel models and show the effectiveness of the proposed methods.

An investigation on fronthaul and millimeter wave technologies for 5G

Abstract.The growing demand for communications and the emergence of new applications have put the capacity, transmission rate and latency of communications systems to a more severe test. In this context, 5G communication technology has emerged. 5G applications are divided into three typical application scenarios: eMBB, URLLC and mMTC. In order to support these applications, the key technologies of 5G need to be studied in depth. This paper firstly investigates the networking architecture of 5G bearer networks, and carries out a detailed analysis and comparison of 5G fronthaul technology, including the optical fibre direct connection solution, passive WDM solution, active WDM/OTN solution and WDM-PON solution. Secondly, this paper introduces 5G millimetre wave technology to achieve large capacity and high spectral efficiency transmission, including direct intensity modulation method, external modulation method, optical heterodyne method, optical injection locking method and optical phase-locked loop method. Finally, this paper provides an outlook on 5G fronthaul technology and millimetre wave technology.

Konversi Antena Mimo 2x2 Frekuensi 2,4 Ghz Menjadi 5,5 Ghz Menggunakan Patch Bowtie Berbasis Dual Slot Segi Empat dan Single Slot Segitiga

Perkembangan antena radar semakin cepat dan beragam, salah satunya adalah antena MIMO (multiple output). Antena MIMO banyak digunakan untuk teknologi 5G karena efisiensi spectral dan fekuensi yang tinggi. Antena MIMO juga merupakan suatu sistem yang menggunakan multi antena baik pengrim (Transmitter) maupun penerima (receiver) yang bisa mengatasi kelemahan pada sistem komunikasi wireless. Penelitian ini merancang sebuah antena mikrostrip MIMO 2X2 dengan menggunakan patch bowtie untuk mengkonversi frekuensi dari 2,4 GHz menjadi 5,5 GHz dengan menambahkan dual slot segiempat dan single slot segitiga. Hasil simulasi menunjukkan penambahan dual slot segiempat dan single slot segitiga pada patch antena bowtie dapat menggeser frekuensi kerja dari 2,4 GHz menjadi 5,5 GHz. Dari hasil simulasi antena MIMO 2X2 didapatkan nilai return loss S11 sebesar -46,5 dB, insertion loss S21 sebesar -25,2 dB, bandwidth sebesar 192,2 MHz, VSWR sebesar 1,00 dan gain sebesar 3,11 dBi. Hasil dari pengukuran antena MIMO menunjukkan perbedaan dari parameter antena 1 dan 2. Hal ini disebabkan adanya ketidaksamaan ukuran dari antena 1 dan antena 2. Pengukuran nilai return loss untuk antena 1 yaitu sebesar -22,32 dB dan -15,63 dB untuk antena 2. Hasil pengukuran insertion loss antena 1 dan 2 memiliki nilai yang sama yaitu -43,5 dB dan untuk lebar bandwidth memiliki perbedaan nilai yaitu 50 MHz untuk antena 1 dan 100 MHz untuk antena 2. Pengukuran nilai VSWR 1 didapatkan nilai sebesar 1,96, VSWR 2 sebesar 1,41. The development of radar antennas is getting faster and more diverse, one of which is the MIMO (multiple output) antenna. MIMO antennas are widely used for 5G technology because of their high spectral efficiency and frequency. MIMO antenna is also a system that uses multiple antennas, both transmitter and receiver which can solving the weaknesses in wireless communication systems. The research designed a 2X2 MIMO microstrip antenna using a patch bowtie to convert the frequency from 2.4 GHZ to 5.5 GHz by adding dual rectangular slots and single triangular slots. The simulation results show that the addition of dual rectangular slots and single triangular slots on the patch bowtie antenna can shift the working frequency from 2.4 GHz to 5.5 GHz. From the simulation results of MIMO 2X2 antenna, the return loss value of S11 is -46.5 dB, insertion loss S21 is -25.2 dB, bandwidth is 192.2 MHz, VSWR is 1.00 and gain is 3.11 dBi. The results of the MIMO antenna measurements show differences in the parameters of antennas 1 and 2. This is due to the difference size of antenna 1 and antenna 2. The measurement of the return loss value for antenna 1 is -22.32 dB and -15.63 dB for antenna 2 The results of the insertion loss measurements for antennas 1 and 2 have the same value, which is -43.5 dB and for the width of the bandwidth has a different value, 50 MHz for antenna 1 and 100 MHz for antenna 2. Measurement of the value of VSWR 1 obtained a value of 1.96, VSWR 2 is 1.41.

Investigation and Suppression of RF Leakage Power in Front End Wireless Devices

In this modern Communication Wireless System, Frequency Division Duplex (FDD) is mostly used. Duplex is a device to separate Transmitter and Receiver signals. Transmitter or Power leakage causes from limited isolation performance of the duplexer. Various Techniques of Modulation using Orthogonal Frequency Division Multiplexing (OFDM) provided better solution to cancel this leakage. The OFDM provides high spectral efficiency, lower multi-path distortion and to eliminate inter symbol interference (ISI). Fast Fourier Transform implemented modulation and demodulation functions more efficiently. Using simulation result of the various parameters are analysed. In addition, Comparison of the table between Bit rate error value, Signal strength throughput, Power consumption and Mean square error values obtained in the OFDM systems.

Experimental evaluation of a linear angular momentum multiplexed radio link for moving platforms

Linear angular momentum multiplexing (LAMM) has recently been proposed for high spectral-efficiency communications between moving platforms, such as between trains and ground infrastructure. We present performance results obtained from a scale experimental system comprising a 2 × 2 antenna system operating at 2.35 GHz. The link transmitted two independent video streams, using RF pre-coding and software-defined radios to modulate and up/down-convert the signals. Linear motion is introduced to demonstrate the translation-invariance of the technique. We interpret the measured data with the aid of an analytical model to show that crosstalk between the two channels is at levels low enough to consistently support the video streams without interruption. Specifically, our results show spectral efficiency is consistently higher when LAMM coding is enabled compared with an uncoded channel.