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Abstract

MIMO technology has become very popular in a wireless communication system because of the many advantages of multiple antennas at the transmitting end and receiving end. The main advantages of MIMO systems are higher data rate and higher reliability without the need of extra power and bandwidth. The MIMO system provides higher data rate by using spatial multiplexing technique and higher reliability by using diversity technique. The MIMO systems have not only advantages, but also have disadvantages. The main disadvantage of MIMO system is that the multiple antennas required extra high cost RF modules. The extra RF modules increase the cost of wireless communication systems. In this research, the antenna selection techniques are proposed to minimize the cost of MIMO systems. Furthermore, this research also presents techniques for antenna selection to enhance the capacity of channel in MIMO systems.

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Authors and Affiliations

Dalveer Kaur
Neeraj Kumar
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Abstract

Multiple input multiple output (MIMO) is a multiple antenna technology used extensively in wireless communication systems. With the ever increasing demand in high data rates, MIMO system is the necessity of wireless communication. In MIMO wireless communication system, where the multiple antennas are placed on base station and mobile station, the major problem is the constant power of base station, which has to be allocated to data streams optimally. This problem is referred as a power allocation problem. In this research, singular value decomposition (SVD) is used to decouple the MIMO system in the presence of channel state information (CSI) at the base station and forms parallel channels between base station and mobile station. This practice parallel channel ensures the simultaneous transmission of parallel data streams between base station and mobile station. Along with this, water filling algorithm is used in this research to allocate power to each data stream optimally. Further the relationship between the channel capacity of MIMO wireless system and the number of antennas at the base station and the mobile station is derived mathematically. The performance comparison of channel capacity for MIMO systems, both in the presence and absence of CSI is done. Finally, the effect of channel correlation because of antennas at the base stations and the mobile stations in the MIMO systems is also measured.

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Authors and Affiliations

Dalveer Kaur
Neeraj Kumar
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Abstract

The uncertainty in the supply of crude oil, increasing the number of vehicles and rising air pollution, especially in urban areas, has prompted us to look for alternative fuels. It is understood that using Compressed Natural Gas (CNG) in IC engines could be a mid-term solution to these problems. It is well established that CNG has better combustion characteristics and low emissions compared to conventional gasoline and diesel fuel. In the present study, an experiment was conducted to evaluate the engine performance and exhaust emissions using various percentages of CNG in dual fuel mode. CNG was mixed in the intake manifold’s air stream, and diesel was injected after the compression of the CNG air mixture. This paper presents experimental results of 40%,60%, and 80% CNG in the air stream. Engine performance and emissions are presented and discussed at a speed of 1200 rpm to 1500 rpm in steps of 50 rpm. The results of the experiments showed that adding CNG to diesel engines in dual-fuel combustion significantly impacted performance and emissions. Compared to single diesel fuel combustion, dual fuel combustion increases brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) at all CNG energy shares and engine speeds. Carbon monoxide (CO) and hydrocarbon (HC) emissions were increased, while nitrogen oxide (NOX) and smoke opacity were decreased in dual fuel combustion compared to single diesel fuel.
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Authors and Affiliations

Neeraj Kumar
1
ORCID: ORCID
Bharat Bhushan Arora
ORCID: ORCID
Sagar Maji
1
ORCID: ORCID

  1. Delhi Technological University, Delhi, India

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