Multi-Parameter Based Scheduling for Multi-user MIMO Systems

Chanthirasekaran, K.,Bhagyaveni, M.A.,Parvathy, L. Rama The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.6

Multi-user multi-input multi-output (MU-MIMO) system has attracted the 4^th generation wireless network as one of core technique for performance enrichment. In this system rate control is a challenging problem and another problem is optimization. Proper scheduling can resolve these problems by deciding which set of user and at which rate the users send their data. This paper proposes a new multi-parameter based scheduling (MPS) for downlink multi-user multiple-input multiple-output (MU-MIMO) system under space-time block coding (STBC) transmissions. Goal of this MPS scheme is to offer improved link level performance in terms of a low average bit error rate (BER), high packet delivery ratio (PDR) with improved resource utilization and service fairness among the user. This scheme allows the set of users to send data based on their channel quality and their demand rates. Simulation compares the MPS performance with other scheduling scheme such as fair scheduling (FS), normalized priority scheduling (NPS) and threshold based fair scheduling (TFS). The results obtained prove that MPS has significant improvement in average BER performance with improved resource utilization and fairness as compared to the other scheduling scheme.

Cognitive Relay Networks with Underlay Spectrum Sharing and Channel Estimation Error: Interference Probability and BER Analysis

Khuong Ho-Van 한국통신학회 2014 Journal of communications and networks Vol.16 No.3

This paper proposes accurate interference probability and bit error rate formulas for cognitive relay networks with underlay spectrum sharing and channel estimation error (CEE). Numerous results reveal that the CEE not only degrades the performance of secondary systems (SSs) but also increases interference power caused by SSs to primary systems (PSs), eventually unfavorable to both systems. A solution to further protect PSs from this effect through reducing the power of secondary transmitters is investigated and analyzed.

추정 BER을 이용한 다중 밴드 전송 기법의 가중치 알고리즘 연구

신지은,정현우,정지원,Shin, Ji-Eun,Jeong, Hyun-Woo,Jung, Ji-Won 한국음향학회 2021 韓國音響學會誌 Vol.40 No.4

수중통신에서 빠른 채널 특성의 변화에 따른 성능 감소를 보상하기 위해, 동일한 데이터를 여러 개의 주파수 대역으로 전송하는 다중 밴드 기법을 적용한다. 그러나 다중 밴드의 적용 시 특정한 밴드의 성능 열화로 전체 성능이 감소하는 현상이 발생한다. 이를 극복하기 위해 각 밴드의 오류율을 분석하여 성능이 열악한 밴드에 낮은 가중치를 할당할 수 있다. 따라서 본 논문에서는 추정 Bit Error Rate(BER)을 이용한 가중치 설정 방법을 제안한다. 추정 BER을 이용한 가중치 설정 방식은 복호 된 데이터와 복조 후 데이터의 성능 차이를 이용하여 수신된 데이터의 신뢰도를 측정하며, 측정된 값을 이용하여 각 밴드별 가중치를 설정해 복호기로 입력하면 성능이 향상된다. 본 논문에서는 터보 부호화 기법을 적용하였으며 시뮬레이션을 이용하여 최적의 가중치 값을 설정해 해상 실험을 한 결과 추정 BER을 이용한 가중치 설정을 통해 오류를 모두 정정할 수 있었다.

Multi-Parameter Based Scheduling for Multi-user MIMO Systems

K. Chanthirasekaran,M.A. Bhagyaveni,L. Rama Parvathy 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.6

Multi-user multi-input multi-output (MU-MIMO) system has attracted the 4<SUP>th</SUP> generation wireless network as one of core technique for performance enrichment. In this system rate control is a challenging problem and another problem is optimization. Proper scheduling can resolve these problems by deciding which set of user and at which rate the users send their data. This paper proposes a new multi-parameter based scheduling (MPS) for downlink multi-user multiple-input multiple-output (MU-MIMO) system under space-time block coding (STBC) transmissions. Goal of this MPS scheme is to offer improved link level performance in terms of a low average bit error rate (BER), high packet delivery ratio (PDR) with improved resource utilization and service fairness among the user. This scheme allows the set of users to send data based on their channel quality and their demand rates. Simulation compares the MPS performance with other scheduling scheme such as fair scheduling (FS), normalized priority scheduling (NPS) and threshold based fair scheduling (TFS). The results obtained prove that MPS has significant improvement in average BER performance with improved resource utilization and fairness as compared to the other scheduling scheme.

An Add-On Type Real-Time Jitter Tolerance Enhancer for Digital Communication Receivers

Sewook Hwang,Junyoung Song,Sang-Geun Bae,Yeonho Lee,Chulwoo Kim IEEE 2016 IEEE transactions on very large scale integration Vol.24 No.3

<P>An add-on type real-time jitter tolerance enhancer (JTE) is presented in this paper. The proposed JTE can improve high-frequency jitter tolerance (JTOL) by using a real-time phase alignment scheme. A mathematical analysis for an advanced bit error rate (BER) prediction method is also introduced. The proposed circuit is applicable to various types of receivers, such as referenceless receivers, receivers with a reference clock source, and source-synchronous receivers. The referenceless receiver with the proposed JTE achieved an out-of-band JTOL of 0.71 UIpp at 100 MHz with <10(-12) BER. This is 196% higher than a conventional receiver without the JTE. The source-synchronous receiver with the proposed JTE achieved 0.92 UIpp at 300 MHz with <10(-12) BER. Total core areas of the receiver and JTE are 0.19 and 0.07 mm(2) in a 0.13-mu m CMOS process, respectively. The power consumption of the receiver is 38 mW at 5.4 Gbit/s, and the JTE dissipates 22 mW.</P>

광 직교코딩 시뮬레이션에 의한 지연선-광CDMA 시스템의 해석

김남국,이주희,전상영 慶熙大學校 레이저 工學硏究所 1999 레이저공학 Vol.10 No.-

In this paper, we present the performance of Delay Line-Optical CDMA System for Multi User Environment using Optical Orthogonal Coding Simulation. We have developed the program of Optical Orthogonal Coding Simulation to improve Auto-and Cross-Correlation properties. and we consisted of both encoder and decoder using optimal optical orthogonal codes with optimal condition rate. Then, increasing threshold value, we obtained a low bit error rate.

Performance analysis of physical-layer network coding with QPSK modulation in wireless IoT networks

염정선,고갑석,Hu Jin,정방철 한국통신학회 2022 ICT Express Vol.8 No.3

In this paper, we mathematically analyze bit-error rate (BER) and diversity order of physical-layer network coding (PNC) scheme in the two-way relay channel (TWRC) under the assumption of multiple antennas at relay node. We assume the quadrature phase shift keying (QPSK) modulation for simple data transmission in IoT applications, and max–min transmit antenna selection (TAS) scheme in the broadcast (BC) phase for achieving full diversity gain. In particular, we obtain the upper bound of BER at the multiple access (MA) phase, while deriving the exact BER performance at the BC phase. To the best our knowledge, the mathematical analysis in this paper is the first analytical results in the literature. Through computer simulations, the analytical results are validated.

NJ+: An Efficient Congestion Control Mechanism for Wireless Networks

( Jaehyung Lee ),( Jungrae Kim ),( Minu Park ),( Jahwan Koo ),( Hyunseung Choo ) 한국인터넷정보학회 2008 KSII Transactions on Internet and Information Syst Vol.2 No.6

Transmission control protocols have to overcome common problems in wireless networks. TCP employing both packet loss discrimination mechanism and available bandwidth estimation algorithm, known as the good existing solution, shows significant performance enhancement in wireless networks. For instance, TCP New Jersey which exhibits high throughput in wireless networks intends to improve TCP performance by using available bandwidth estimation and congestion warning. Even though it achieves 17% and 85% improvements in terms of goodput over TCP Westwood and TCP Reno, respectively, we further improve it by exploring maximized available bandwidth estimation, handling bit-error-rate error recovery, and effective adjustment of sending rate for retransmission timeout. Hence, we propose TCP NJ+, showing that for up to 5% packet loss rate, it outperforms other TCP variants by 19% to 104% in terms of goodput when the network is in bi-directional background traffic.

전송기준신호의 평균을 이용한 차등 UWB 시스템의 성능개선

황준혁,김석찬,정기웅,강봉순 에스케이텔레콤 (주) 2010 Telecommunications Review Vol.20 No.3

본 논문은 UWB-TR(Ultra WideBand-Transmitted Reference) 시스템에서 효과적으로 비트오류확률(BER:Bit Error Rate)을 개선하는 방법에 대해서 제안하였다. 제안하는 DATR(Differential Averaged TR) 시스템은 기존의 ATR(Averaged TR) 시스템과 DTR(Differential TR) 시스템의 장점을 결합하여 이전에 전송한 데이터신호를심볼 단위로 평균하여 차등기법을 적용함으로서 상관기의 기준신호를 개선하여 BER을 향상시키고 전송신호에 기준신호를 전송하지 않음으로서 데이터 전송률을 향상시킬 수 있었다. 이론적인 성능 분석과 모의실험을 통하여 제안하는 시스템이 기존의 UWB-DTR 시스템에 비해서 BER이 향상됨을 보인다.

MHP 펄스를 이용하는 PO-THMA UWB 시스템의 성능분석

황준혁 한국지식정보기술학회 2014 한국지식정보기술학회 논문지 Vol.9 No.6

In this paper, we proposed a PO-THMA(pulse order-time hopping multiple access) scheme in UWB(ultra-wide band) system. The proposed PO-THMA UWB system using two-dimensional code combines MHP(modified Hermite polynomial) pulse order and time hopping code. The MHP pulses have a mutually orthogonal property between different order and that property makes simultaneous transmission at the same time slot regardless of collision in the THMA UWB system. We derive the general form of correlation function for MHP pulses and multiple access interference and analyze BER of the scheme over AWGN(additive white Gaussian noise) channel. Theoretical analysis and simulation results show that proposed PO-THMA UWB system increases transmission capacity or has better BER(bit error rate) than conventional THMA UWB system. The proposed PO-THMA UWB system is expected to be utilized in the high data rate wireless communication system with low power and low complexity. With these benefits, the studied PO-THMA UWB system can be used in low power sensor networks and short range wireless communication applications with high transmission rate.