• Title/Summary/Keyword: Noise antenna

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Design and Fabrication of the Ka-Band Receive Module for Millimeter Wave Seeker (밀리미터파 탐색기를 위한 Ka-대역 수신기 모듈의 설계 및 제작)

  • Yang, Seong-Sik;Lim, Ju-Hyun;Song, Sung-Chan
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.1
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    • pp.78-84
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    • 2012
  • In this paper, we introduced the design technique about a Ka band receive module for millimeter wave seekers. The receiver module consists of a waveguide, circulator and transition for antenna connection, and a limiter and gain control amplifier for receiver protection. This module is comprised of a sum, azimuth and elevation channel for receiving monopules signal, and a SLB channel for the acquisition of jamming signal. In this paper, receiver gain and range of gain control dependent on ADC nonlinear characteristic was analyzed and designed for wide dynamic range receive. In the test result of the fabricated Ka-band receive, the frequency band is 1 GHz, the noise figure is as low as 8.2 dB, the gain is $56{\pm}2dB$, the dynamic range is 135 dB, the gain congtrol is more than 86 dB, the channel isolation is more than 35 dB.

Adaptive Antenna Array for DOA Estimation Utilizing Orthogonal Weight Searching (직교가중치 탐색방법을 이용한 도착방향 추정 적응어레이 안테나)

  • 오정호;최승원;이현배;황영준
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.8 no.2
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    • pp.116-125
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    • 1997
  • This paper presents a novel method, entitled Orthogonal Weights Searching(OWS), for the Direction-Of-Arrival(DOA) estimation. Utilizing the modified Conjugate Gradient Method(MCGM), the weight vector which is orthogonal to the signal subspace is directly computed from the signal matrix. The proposed method does not require the computation of the eigenvalues and eigenvectors. In addition, the new technique excludes the procedure for the detection of the number of signals under the assumption that the number of weights in the array is greater than the number of input signals. Since the proposed technique can be performed independently of the detection procedure, it shows a good performance in adverse signal environments in which the detection of the number of array inputs cannot be obtained successfully. The performance of the proposed technique is compared with that of the convectional eigen-decomposition method in terms of angle resolution for a given signal-to-noise ratio(SNR) and a required amount of computations.

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Estimation of the sharing criteria between HAPS System and Cellular IMT-2000 system (HAPS 시스템과 셀룰라 IMT-2000 시스템간 주파수 공유 기준 평가)

  • Kim, Bong-Seok;Park, Jong-Min;Ku, Bon-Jun;Ahn, Do-Sub;Kang, Young-Heung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.8B
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    • pp.819-825
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    • 2002
  • Resolution 221 requests the ITU-R to conduct studies, as a matter of urgency, on the feasibility of utilizing HAPS system as a base station to provide IMT-2000 services. And HAPS base stations should not cause harmful interference to the cellular IMT-2000 services. To study on the interference between HAPS system and cellular system is divided into two cases. One is the interference into HAPS system from the cellular system and the other is the interference into the cellular system from HAPS system. Since the former case has been already studied[1]. this paper describes the interference the interference to the noise power ration(I/N) with various parameters, such as the transmitting power, the number of users per cell, maximum antenna gain and the multibeam cell radius of HAPS. With the proposed estimation, we can determine the optimum values of various parameters in HAPS IMT-2000 system.

A Study on Interference Cancelling Receiver with Adaptive Blind CMA Array (적응 블라인드 CMA 어레이를 이용한 간섭 제거 수신기에 관한 연구)

  • 우대호;변윤식
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.4A
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    • pp.330-335
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    • 2002
  • In the direct sequence code division multiple access system, the problem of multiple access interference due to multiple access is generated. A interference cancelling receiver is used to solve this problem. The conventional interference cancelling receiver is structure of successive interference canceller using antenna array. In this structure, the difference of between method I and method II depends on updating weight vector. In this paper, the adaptive blind CMA array interference cancelling receiver using cost function of constant modulus algorithms is proposed to update weight vector at conventional structure. The simulation compared the proposed interference cancelling receiver with two conventional interference cancelling receivers by signal to interference ratio and bit error rate curve under additive white Gaussian noise environment. The simulation results show that the proposed receiver has about the gain of SIR of 1.5[dB] more than method I which is conventional receiver at SIR curve, and about the gain of SIR of 0.5(dB) more than method II. In BER curve, the proposed IC receiver about the gain of SNR of 2[dB] more than method I and about the gain of SNR of 0.5[dB] more than method If, Thus, the proposed interference cancelling receiver has the higher performance than conventional interference cancelling receivers.

A Spectrum Sharing Model for Compatibility between IMT-Advanced and Digital Broadcasting

  • Hassan, Walid A.;Rahman, Tharek Abd
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.9
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    • pp.2073-2085
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    • 2012
  • Recently, the International Telecommunication Union allocated the 470-862 MHz band to the digital broadcasting (DB) service. Moreover, the 790-862 MHz sub-band will be allocated to the next-generation mobile system, known as the International Mobile Telecommunication - Advanced (IMT-A), and to the DB on a co-primary basis in the year 2015. Currently, two candidate technologies are available to represent the IMT-A system; the Mobile WiMAX and Long Term Evolution - Advanced (LTE-A). One of the main criteria of the IMT-A candidate is to not cause additional interference to the primary service (i.e., DB). In this paper, we address the spectrum sharing issue between the IMT-A candidates and the DB service. More precisely, we investigate the interference effect between the DB service and the mobile network, which could be either LTE-A or WiMAX. Our study proposes a spectrum sharing model to take into account the impact of interference and evaluates the spectrum sharing requirements such as frequency separation and separation distance. This model considers three spectrum sharing scenarios: co-channel, zero guard band, and adjacent channel. A statistical analysis is performed, by considering the interferer spectrum emission mask and victim receiver blocking techniques. The interference-to-noise ratio is used as an essential spectrum sharing criterion between the systems. The model considers the random distribution of the users, antenna heights, and the bandwidth effect as well as the deployment environment in order to achieve spectrum sharing. The results show that LTE-A is preferable to WiMAX in terms of having less interference impact on DB; this can eventually allow the operation of both services without performance degradation and thus will lead to efficient utilization of the radio spectrum.

Bluetooth Beacon Planing Considering Position Estimation Accuracy in Small and Isolated In-Door Environment (소형독립공간에서 실내측위 정확도를 고려한 블루투스 비컨 위치선정)

  • Ahn, Heejune;Thuy, Tran Vinh;Lee, Ye Hoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.7
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    • pp.1307-1312
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    • 2015
  • The recent adoption of Bluetooth LE technology in smart phones triggered commercial interest in RSSI-based positioning technology. Estimation error in RSSI measurement due to the antenna pattern, multipath fading, environmental noise has to be considered for designing beacon systems. The paper proposes an analysis method and beacon planning rules for a small and isolated indoor service area, based on probabilistic model of RSSI estimation error. As an practically important guide, the beacons have to be installed at the boundary of the service area to minimize the maximum position error, whereas the beacons have to be evenly distributed in the service space to minimize the average estimation error.

Analysis and measurement of service area of ocean-based DGPS reference station in Korea (국내 해상 DGPS 기준국의 서비스 영역 측정 및 분석)

  • Kim, Young-Wan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.6
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    • pp.1255-1261
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    • 2014
  • Based on the radio wave measurement of korean ocean-based DGPS by season, in this paper, the service coverages of ocean-based DGPS reference stations were analyzed according to the climate and season. The signal strengths and signal-to-noise ratios in the land service areas that are provided by ocean-based DGPS reference stations were measured. The ocean-based DGPS reference station except reference stations on the mountainous terrain and the low ground conductivity provide more than 68% service area in comparison with the designed land service coverage providing by the ocean-based DGPS reference stations. To provide the designed service area that is unrelated to a season, it is necessary to install and operate the DGPS reference station with good ground conductivity and high efficiency antenna. Also, the poor service regions which is generated by obstacles of electric wave on pathway can be resolved by the double service area providing by land-based DGPS reference stations.

Multi-Cell Transmit Diversity Scheme for OFDMA Systems (OFDMA 시스템을 위한 다중 셀 전송 다양성 기법)

  • Seo, Bangwon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37A no.9
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    • pp.721-727
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    • 2012
  • Since a conventional multi-cell transmit diversity scheme depends on the feedback from the user for the channel gain information, its performance gets to severely degrade when the channel varies fast due to the high mobility of the user. Also, transmit power of the base station cannot be fully used in the conventional scheme because only one transmit antenna is used for data transmission. In this paper, we propose a multi-cell transmit diversity scheme appropriate for fast fading channel. In the proposed scheme, channel-independent precoding vector is applied over all transmit antennas and different precoding vectors are applied for neighboring subcarriers so that the received signal is avoided to experience deep fading over multiple neighboring subcarriers. Simulation results show that the proposed scheme has better detector output signal-to-noise ratio (SNR) and bit error rate (BER) performances than the conventional scheme.

Implementation and Performance Analysis of Multi-GNSS Signal Collection System using Single USRP

  • Park, Kwi Woo;Choi, Yun Sub;Lee, Min Joon;Lee, Sang Jeong;Park, Chansik
    • Journal of Positioning, Navigation, and Timing
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    • v.5 no.1
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    • pp.11-20
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    • 2016
  • In this paper, a system that can collect GPS L1 C/A, GLONASS G1, and BDS B1I signals with single front-end receiver was implemented using a universal software radio peripheral (USRP) and its performance was verified. To acquire the global navigation satellite system signals, hardware was configured using USRP, antenna, external low-noise amplifier, and external oscillator. In addition, a value of optimum local oscillator frequency was selected to sample signals from three systems with L1-band with a low sampling rate as much as possible. The comparison result of C/N0 between the signal collection system using the proposed method and commercial receiver using double front-end showed that the proposed system had 0.7 ~ 0.8dB higher than that of commercial receiver for GPS L1 C/A signals and 1 ~ 2 dB lower than that of commercial receiver for GLONASS G1 and BDS B1I. Through the above results, it was verified that signals collected using the three systems with a single USRP had no significant error with that of commercial receiver. In the future, it is expected that the proposed system will be combined with software-defined radio (SDR) and advanced to a receiver that has a re-configuration channel.

Channel Capacity of BLAST based on the Zero-Forcing criterion (Zero-Forcing 기반의 BLAST 채널 용량)

  • Lee, Heun-Chul;Kim, Hee-Jin;Lee, In-Kyu
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.12
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    • pp.34-41
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    • 2008
  • In this paper, we present an asymptotical analysis of channel capacity of Bell labs layered space-time (BLAST) architectures based on a zero-forcing (ZF) criterion in the sense of signal-to-noise ratio (SNR). We begin by introducing a new relationship related to multi-input multi-output (MIMO) channel capacity. We prove that Diagonal Bell Labs Space-Time (DBLAST) attains the lower bound for MIMO channels when interference nulling is carried out based on the ZF-criterion. An exact closed-form expression for the probability density function of the channel capacity is analyzed. Based on the asymptotic behavior of the channel capacity of each layer, closed-form expressions for the asymptotic ergodic capacity are derived for BLAST. Based on the analysis presented in this paper, we gain an insight on the channel capacity behavior for a MIMO channel. Computer simulation results have verified the validity and accuracy of the proposed analysis for a wide range of antenna array sizes.