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Evaluating the Performance of Quasi and Rotated Quasi OSTBC System with Advanced Detection Techniques for 5G and IoT Applications
Published in Mohammed Usman, Mohd Wajid, Mohd Dilshad Ansari, Enabling Technologies for Next Generation Wireless Communications, 2020
Priyanka Mishra, Mehboob-ul-Amin
Multiple transmitting and receiving antennas are used to obtain the diversity gain. As a result, one is able to go for higher spectral efficiencies by increasing the information rates. Because the diversity is directly proportional to the min or max of quantity of transmit or receive antennas, increasing the quantity level of these elements at the either end of the system will result in increased bit rates (Dalton and Georghiades 2005). We define the spatial multiplexing gain (SMG) using the following equation: SMG=limγ→∞Rlnγ.
UWB MIMO Antennas
Published in Chinmoy Saha, Jawad Y. Siddiqui, Yahia M.M. Antar, Multifunctional Ultrawideband Antennas, 2019
Chinmoy Saha, Jawad Y. Siddiqui, Yahia M.M. Antar
Diversity gain can be defined as the increase in time-averaged signal-to-noise ratio due to the diversity scheme over that of a single antenna system (i.e. one diversity channel), provided the SNR is above the reference channel. Alternatively, it can be defined as the amount of reduction in transmitted power when a diversity scheme is introduced over that of a single antenna system, without any loss of performance. Diversity gain of a diversity system can be computed as, DiversityGain=][γcSNRc−γ1SNR1Pγc<γs/SNR
Overview of Cooperative Communications in Wireless Systems
Published in Emad S. Hassan, Security and Data Reliability in Cooperative Wireless Networks, 2018
Time Diversity. Using time diversity the same symbol is transmitted at different time instants provided that the time separation exceeds the coherence time (Tc ) of the channel. This implies that the different transmitted symbols will experience channel realizations that are highly uncorrelated and can be used to obtain diversity. The simplest way to achieve this type of diversity is using a repetition coding scheme. Also, in order to guarantee that the repeated symbols will be transmitted over uncorrelated channel realization, an appropriate interleaver is applied to the stream of symbols to be transmitted. From the diversity gain point of view, the time-diversity system with repetition coding achieves full diversity gain. Nevertheless, the use of repetition coding sacrifices the total bit rate.
MIMO-DRA with triple-band CP & low EM coupling: a methodical design approach
Published in Waves in Random and Complex Media, 2023
Nikesh Kumar Sahu, Ravi Kumar Gangwar
Figure 15 illustrates the selection of MIMO operation mode for optimal system performance. Based on the signal-to-noise ratios (SNRs) of the received signals, distinct MIMO modes are needed to maximize the system performance. Diversity techniques are employed to counteract fading in low SNR situations, and the system's performance is usually measured using the diversity gain (DG) metric. The diversity scheme's effectiveness on communication systems can be measured by DG. In multiple-antenna system, the total efficiency of the best antenna element has always been less than that of a single-antenna system. This is due to the mutual coupling and the extra ohm loss. Thus, to make the result more realistic, an effective DG (EDG) metric is widely used. The EDG of a two-antenna system can be computed by using the expression [31]: where, is the total efficiency of the best antenna element. The calculation of total efficiency is discussed in [32]. Note that, the above EDG expression is an approximate closed-form representation, and it is affected by antenna efficiency and correlation. The EDG values of the proposed MIMO structure are depicted in Table 2. Referring to this table, the obtained EDG values are quite satisfactory, which is owing to the high total efficiency and low correlation values of the proposed structure.
Circularly Polarized Quad-Port MIMO Dielectric Resonator Antenna with Beam Tilting Feature for Vehicular Communication
Published in IETE Technical Review, 2022
Ajay Kumar Dwivedi, Anand Sharma, Ashutosh Kumar Singh, Vivek Singh
A key parameter that is used to assess the MIMO system is the correlation coefficient (ρ). The correlation coefficient provides the information about the channel isolation in a wireless network. If the value of the correlation coefficient is zero, it means that the maximum channel capacity is achieved. The CC indices contemplate the radiation patterns of each element of the MIMO system operating simultaneously. The value of ECC is obtained by [27]. The above equation has a bit complex calculation, it involves 3D radiation pattern measurement and integral part. Here, signifies the 3D radiated filed lines of the MIMO antenna when the power is given in the “i”th port. A significantly large amount of information is received at the receiver side through the various transmitting antennas. Due to the uncorrelation nature of the signal at the receiver side, the level of signal to noise ratio increases and therefore, the better signal reception is achieved. Diversity gain provides the effect of diversity on the wireless communication link. It is calculated by [28,29].
Performance Analysis of a Selection Combining System That Uses the Minimal Interference Algorithm
Published in IETE Journal of Research, 2022
Aleksandra D. Golubovic, Nikola M. Sekulovic, Mihajlo C. Stefanovic, Dejan N. Milic, Zorica B. Nikolic
The maximum diversity gain is achieved when antenna elements are placed sufficiently far apart ensuring independent fading channels. Although it is an uncommon scenario in practice, from a theoretical point of view, it is important to investigate uncorrelated diversity branches. In that case, the joint PDFs of desired signal envelopes and interference signal envelopes are the products of the marginal ones given by [11, Equation (3)]. This is in line with (1) and (2) for ρ=0. Following the procedure described in this section, the PDF of the instantaneous SIR at the output of uncorrelated dual-branch SC receiver employing the MI algorithm is This is also a special case of (6) when the correlation coefficient tends to be 0.