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Effective Noise Figure in Hybrid BF system
Month Year doc.: IEEE yy/xxxxr0 July 2015 Effective Noise Figure in Hybrid BF system Date: YYYY-MM-DD Authors: Ji-Ho Lee, Korea University John Doe, Some Company
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Month Year doc.: IEEE yy/xxxxr0 July 2015 Abstract This contribution presents the theoretical results of noise figure (NF) and gain in hybrid beamforming systems. Ji-Ho Lee, Korea University John Doe, Some Company
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July 2015 Motivation In hybrid beamforming systems, the received signals from multiple antennas are phase corrected by phase shifter and then combined in RF combiner, usually before down-converting at RX. The additional RF blocks (i.e., phase shifter and combiner) are added to RF chain, which increases noise figure. Note that the RF combiner has multiple input signals and single output signals (multi-to-one RF path). In this case, the NF should be appropriately considered for the calculation of carrier to noise ratio (CNR). Ji-Ho Lee, Korea University
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Block Diagram of Hybrid Beamforming
Month Year doc.: IEEE yy/xxxxr0 July 2015 Block Diagram of Hybrid Beamforming Phase shifter LNA Down-converting Low-pass filter ADC Baseband Space-time processing Down-converting Low-pass filter LNA Phase shifter ADC The received signals from each antenna are phase-shifted by phase shifter and combined by combiner after LNA. At baseband, the conventional MIMO space-time processing is performed for multiplexing gain or/and diversity gain. Ji-Ho Lee, Korea University John Doe, Some Company
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Noise Figure Calculation
Month Year Noise Figure Calculation Phase shifter LNA ๐บ ๐ , ๐น ๐ ๐บ ๐ 1 , ๐น ๐ 1 ๐บ ๐ 2 , ๐น ๐ 2 ๐ ๐กโ RF chain Equivalent ๐ ๐กโ RF chain ๐บ ๐ ๐ : ๐ ๐กโ RF blockโs gain of ๐ ๐กโ RF path ๐น ๐ ๐ : ๐ ๐กโ RF blockโs noise figure of ๐ ๐กโ RF path ๐บ ๐ : Overall gain of ๐ ๐กโ RF path ๐น ๐ : Overall noise figure of ๐ ๐กโ RF path ๐น ๐ = ๐น ๐ ๐น ๐ 2 โ1 ๐บ ๐ ๐น ๐ 3 โ1 ๐บ ๐ 1 ๐บ ๐ 2 +โฏ Overall Noise Figure (Friis Equation) Overall Gain ๐บ ๐ = ๐บ ๐ 1 ๐บ ๐ 2 โฏ ๐บ ๐ ๐ John Doe, Some Company
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Multi-to-One Path system
Month Year doc.: IEEE yy/xxxxr0 July 2015 Multi-to-One Path system Combiner ๐บ 1 , ๐น 1 , ๐ 1 ๐ ๐ in,1 , ๐ ๐ in,1 ๐ ๐ out,1 ๐ผ 1 ๐ ๐ in,2 , ๐ ๐ in,2 ๐ ๐ out,2 ๐ผ 2 ๐บ 2 , ๐น 2 , ๐ 2 Array output ๐ ๐ out , ๐ ๐ out ๐ผ ๐ ๐ ๐ in,๐ , ๐ ๐ in,๐ ๐ ๐ out,๐ ๐บ ๐ , ๐น ๐ , ๐ ๐ ๐ ๐ in,๐ : Input signal power of ๐ ๐กโ RF path ๐ ๐ in,๐ : Input noise power of ๐ ๐กโ RF path ๐บ ๐ : Overall gain of ๐ ๐กโ RF path ๐น ๐ : Overall noise figure of ๐ ๐กโ RF path ๐ ๐ : Insertion phase shift of ๐ ๐กโ RF path ๐ ๐ out,๐ : Output noise power of ๐ ๐กโ RF path ๐ผ ๐ : Amplitude combining coefficient of ๐ ๐กโ RF path ๐ ๐ out : Output signal power of combiner ๐ ๐ out : Output noise power of combiner Ji-Ho Lee, Korea University John Doe, Some Company
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Equivalent Single-Path system
Month Year doc.: IEEE yy/xxxxr0 July 2015 Equivalent Single-Path system ๐ ๐ in,1 , ๐ ๐ in,1 ๐บ 1 , ๐น 1 , ๐ 1 ๐ผ 1 ๐ ๐ in,2 , ๐ ๐ in,2 ๐ ๐ in,eff , ๐ ๐ in,eff ๐บ eff , ๐น eff Array output ๐ ๐ out,eff , ๐ ๐ out,eff ๐บ 2 , ๐น 2 , ๐ 2 ๐ผ 2 Array output ๐ ๐ out , ๐ ๐ out ๐บ eff : Effective overall gain of single RF path ๐น eff : Effective overall noise figure of single RF path ๐ ๐ in,eff , ๐ ๐ out,eff : Effective signal power of single RF path ๐ ๐ in,eff , ๐ ๐ out,eff : Effective noise power of single RF path ๐ ๐ in,๐ , ๐ ๐ in,๐ ๐ผ ๐ ๐บ ๐ , ๐น ๐ , ๐ ๐ For an analysis purpose, a multi-to-one path system is converted into an equivalent single-path system. We assume that the total input, output power of multi-to-one-path system and equivalent single-path system are identical, such that the above two figures are equivalent. Ji-Ho Lee, Korea University John Doe, Some Company
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Array output ๐ ๐ out,eff , ๐ ๐ out,eff
Month Year doc.: IEEE yy/xxxxr0 July 2015 Effective Gain ๐ ๐ in,eff , ๐ ๐ in,eff ๐บ eff , ๐น eff Array output ๐ ๐ out,eff , ๐ ๐ out,eff The effective gain of the array system is given to be [1] If all signal paths are identical ( ๐บ 1 = ๐บ 2 =โฏ ๐บ ๐ =๐บ), we have If all the ๐ผ ๐ are 1 ( ๐ผ 1 = ๐ผ 2 =โฏ= ๐ผ ๐ =1), we have ๐บ ๐๐๐ = ๐ ๐ out,eff ๐ ๐ in,eff = 1 ๐ โ ๐=1 ๐ ๐บ ๐ โ ๐ ๐ ๐ โ๐(๐โ1)โ๐ โ ๐ผ ๐ 2 ๐บ ๐๐๐ = ๐บ ๐ โ ๐=1 ๐ ๐ผ ๐ 2 ๐บ ๐๐๐ =๐บ Ji-Ho Lee, Korea University John Doe, Some Company
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Effective Noise Figure
Month Year doc.: IEEE yy/xxxxr0 July 2015 Effective Noise Figure ๐ ๐ in,eff , ๐ ๐ in,eff ๐บ eff , ๐น eff Array output ๐ ๐ out,eff , ๐ ๐ out,eff The effective noise figure of the array system is given to be [1] If all signal paths are identical ( ๐น 1 = ๐น 2 =โฏ= ๐น ๐ =๐น), we have If all the ๐ผ ๐ are 1 ( ๐ผ 1 = ๐ผ 2 =โฏ= ๐ผ ๐ =1), we have ๐น ๐๐๐ = ๐ ๐ out,eff ๐บ eff โ ๐ ๐ in,eff = ๐โ ๐=1 ๐ ๐บ ๐ โ ๐น ๐ โ ๐ผ ๐ ๐=1 ๐ ๐บ ๐ โ ๐ ๐ ๐ โ๐(๐โ1)โ๐ โ ๐ผ ๐ 2 ๐น ๐๐๐ =๐นโ๐โ ๐=1 ๐ ๐ผ ๐ ๐=1 ๐ ๐ผ ๐ 2 ๐น ๐๐๐ =๐น Ji-Ho Lee, Korea University John Doe, Some Company
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Month Year doc.: IEEE yy/xxxxr0 July 2015 Conclusion We contribute to calculating the noise figure and gain in hybrid beamforming system. Ji-Ho Lee, Korea University John Doe, Some Company
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Month Year doc.: IEEE yy/xxxxr0 July 2015 References Junghyun Kim, Jinho Jeong, and Sanggeun Jeon, "Improvement of Noise Performance in Phased-Array Receivers", ETRI Journal, vol. 33, no.2, pp , April (2011) Ji-Ho Lee, Korea University John Doe, Some Company
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