An Overview of Diversity Techniques in Wireless Communication Systems (original) (raw)
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Wireless communication technology is now popular worldwide and has made mobile communication very attractive and in high demand. For higher data rates to meet the ever increasing demands in mobile communications, multiple-input multiple-output (MIMO) technology has been standardized as the 4G communication systems. MIMO, a wireless communication system which utilises multiple antennas at both sides of the transmission link, has received high attention in the last few decades due to its ability to achieve high data rate transmission. Several papers have presented different techniques in the implementation of MIMO wireless systems which include diversity methods. Physical diversity is one of these methods that is well known and can be used to combat multipath fading, a common problem in wireless communications. This paper summarizes physical diversity as well as virtual diversity techniques. The paper shows that unlike the former, virtual diversity methods such as co-operative diversi...
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Now-a-days the requirements of wireless communication are to have high voice quality, high data rates, multimedia features, lightweight communication devices etc. But the wireless communication channel suffers from much impairment .One of them is fading which is due to the effect of multiple propagation paths, and the rapid movement of mobile communication devices. In a typical wireless communication environment, multiple propagation paths often exist from a transmitter to a receiver due to scattering by different objects. Signal copies following different paths can undergo different attenuation, distortions, delays and phase shifts. So, this is necessary to reduce the problem of fading, but not at the cost of extra power or additional bandwidth. One effective solution is proposed for wireless system named diversity, with out the requirement of power or extra bandwidth. This paper discusses about the characteristics of fading channels and a broad classification of various diversity ...
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The exploiters of the wireless communication demands for higher data rates, acceptable voice quality with higher network capacity confined due to limited accessibility of radio frequency spectrum, Channel capacity, bandwidth, physical areas and transmission problems caused by different factors like fading and multipath distortion. As in wireless systems it is required to have higher voice quality and high bit rate data services as compared to the present cellular mobile radio standards (up to 2 Mbits/sec). Therefore the key challenge faced by future wireless communication systems is to provide high quality of service (Qos) i.e high data rate wireless access. There are many performance abjection factors in wireless communication channels but FADING problem is the leading worsening problem. In this paper, we studied various transmit diversity techniques in multiple-input multiple-output (MIMO) wireless communication systems. In wireless communication fading of channels is the serious ...
A simple transmit diversity technique for wireless communications
IEEE Journal on Selected Areas in Communications, 1998
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Diversity Technique And Modulation Method Used To Reduce Fading in Wireless Communication Pradeep
— Wireless communication has made everyone's life easy. Wireless network provides high speed mobility for data and voice signal. But wireless communication suffers from a problem namely fading, means multipath propagation of signal. Diversity is the technique used in wireless communication system to improve the performance over a communication channel i.e. used to remove fading from the channel. Space diversity is also known as Antenna Diversity that uses two or more antennas to improve the quality and reliability of a wireless link. MIMO is the most powerful diversity technique used in wireless communication. In this paper we analyzed with several antennas (MIMO i.e. multiple input multiple output) so as to obtain the space diversity. Also there is Architectural Comparison between Conventional MIMO-OFDM receiver design and orthogonal MIMO OFDM design. This paper is focused on the improvements obtained in the quality of data transmission.
International Journal of Computer Applications, 2014
In wireless communication systems antenna diversity is an important technique to combat deep fading to improve the system performance and to increase the channel capacity. The fast and random fluctuation of the received signal strength is usually called fading. Diversity technique has been taken into consideration to mitigate the effects of fading by generating several copies of the signal, which experience independent or estimated independent fading, to decrease the probability of instantaneous deep fades. This paper presents the performance analysis of a system in various diversity mechanism environments by improving bit error rate (BER).
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Characteristics of a wireless communication channel are subjected to a large scale deterioration process, referred to as the problem of fading. This paper discusses different techniques for mitigating the fading problems. One solution to the problem is to add a fading margin on the transmitter, but it is not an effective solution. The other solution is to use an alternative statistical behavior of fading channels (applying the basic concepts of diversity), which use two or more inputs on the receiver to ensure the correlation of signal. So, the diversity technique is used to improve system performance in fading channels. Instead of transmitting and receiving the desired signal through one channel, we have L copies of desired signal transferred over M different channels. This paper presents analytical results of the probability of error for diversity techniques which use Rayleigh Fading Channel for BPSK modulation.
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Diversity is a powerful technique to mitigate fading, hence multiple antenna diversity which includes; multiple devices, spatial diversity, cooperative diversity which uses multiple-element transmitter arrays enhance performance greatly in modern wireless communication networks. Appropriate combining at the receiver realizes diversity gain. major interest in this write up is the MIMO {Multiple-input and Multiple-output} antenna method, it is one of the best forms of smart antenna technology and Dynamic control processes for reducing fading over channels by multiple antenna diversity techniques