Wyniki wyszukiwania - BazTech

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Performance Improvement for Vehicular Communications Using Alamouti Scheme with High Mobility

Yousseﬁ My Abdelkader, Mouhsen Ahmed

Journal of Telecommunications and Information Technology

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2020

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nr 3

47--56

EN

The IEEE 802.11p standard is the basic protocol for wireless access in a vehicular environment (WAVE), providing high throughput for multimedia and high quality for vehicular transmissions. However, IEEE 802.11p fails to offer any multi-antenna approaches. In this paper, a multipleinput single-output (MISO) implementation with orthogonal frequency division multiplexing (OFDM), aiming to improve the performance of IEEE 802.11p, is proposed. The authors investigate the impact of time-varying channel on the performance of Alamouti space-time block codes (STBC) in OFDM systems. The Alamouti STBC approach shows good performance in slow time-varying environments, while its Alamouti space frequency block codes (SFBC) counterpart performs better over fast time-varying environments. An adaptive switching scheme is proposed to select appropriate spaceblock coding (STBC or SFBC) in vehicular channels with high mobility levels. It is shown that the proposed adaptive scheme provides better performance compared with traditional spaceblock codes.

2

Hardware Implementation of MISO on Orthogonal Frequency Division Multiplexing Platform with the Help of Alamouti Algorithm

Kilaru S.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 2

137--143

EN

Many software based OFDM techniques were proposed from last half decade to improve the performance of the system. This paper tried to implement the same with Hardwar implementation. We created Hardware based MISO platform with OFDM. We implemented Alamouti algorithm on this test bed. The test bed is implemented with the help of Field Programmable Gate Array (FPGA). The test bed is functionalized with the help of FPGA through Xilinx based system generator for DSP. In this paper we considered the 2×1 MISO implementation with Alamouti algorithm. The simulation results showed that BER and SNR are considerably high for MISO than SISO. The results also proved that proposed OFDM based Alamouti implementation for MISO is excellent in all performance criterions.

3

Comparative Analysis of Channel Estimation Techniques in SISO, MISO and MIMO Systems

Obinna O., Kennedy O., Osemwegie O., Nsikan N.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 3

299--304

EN

The ever-growing need for high data rate, bandwidth efficiency, reliability, less complexity and less power consumption in our communication systems is on the increase. Modern techniques have to be developed and put in place to meet these requirements. Research has shown, that compared to conventional Single Input Single Output (SISO) systems, Multiple-Input Single Output (MISO), and Multiple-Input Multiple-Output (MIMO) can actually increase the data rate of a communication system, without actually requiring more transmit power or bandwidth. This paper aims at the investigation of the existing channel estimation techniques. Based on the pilot arrangement, the block type and comb type are compared, employing the Least Square estimation (L.S) and Minimum Mean Squared Error (MMSE) estimators. Pilots occupy bandwidth, minimizing the number of pilots used to estimate the channel, in order to allow for more bandwidth utilization for data transmission, without compromising the accuracy of the estimates is taken into consideration. Various channel interpolation techniques and pilot-data insertion ratio are investigated, simulated and compared, to determine the best performance technique with less complexity and minimum power consumption. As performance measures, the Mean Squared Error (MSE) and Bit Error Rate (BER) as a function of Signal to Noise power Ratio (SNR) of the different channel estimation techniques are plotted, in order to identify the technique with the most optimal performance. The complexity and energy efficiency of the techniques are also investigated. The system modelling and simulations are carried out using Matlab simulation package. The MIMO gives the optimum performance, followed by the MISO and SISO. This is as a result of the diversity and multiplexing gain experienced in the multiple antenna techniques using the STBC.

4

Zastosowanie techniki MIMO w systemach radiowych B3G

Dziunikowski W., Wągrowski M.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2005

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nr 2-3

60-67

PL

Przedstawiono aktualnie prowadzone prace w zakresie zastosowania technik MIMO i MISO w systemach radiowych B3G. Opisano koncepcję MIMO oraz rozwiązanie typu BLAST. Scharakteryzowano prace badawcze związane z tym zagadnieniem, prowadzone w ramach 5. oraz 6. Programu Ramowego. Przedstawiono stan prac standaryzacyjnych związanych z wdrożeniem techniki MIMO w bezprzewodowych sieciach lokalnych oraz sieci UMTS, a także dostępne rozwiązania komercyjne.

EN

This article presents an overview of research activities concerning the deployment of MIMO and MISO systems in B3G wireless communications. At first, a concept of MIMO and BLAST solution is presented. Next, projects regarding this concept, funded by European Union in the 5th and in the 6th Framework Program are shortly characterized. Additionally, the state-of-the-art of standardization work regarding the utilization of MIMO systems in wireless local area networks and UMTS network, as well as, commercial solutions are presented.