• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.94-98
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• 2017

In this paper, we design a transmission / receiver structure to provide additional data service based on Mobile MMT in hybrid network environment. Mobile MMT is an extended standard of MMT, the next generation multimedia transmission protocol. MMT defines technologies for efficiently transmitting multimedia and supporting various types of data transmission and bidirectional services over heterogeneous networks based on IP. The Mobile MMT further defines the extended functions to provide functions specific to the mobile network based on the existing MMT technology. In this paper, we design and propose a additional data service scenario and additional data transmission / receiver structure that can receive additional data related to contents delivered through broadcasting network and additional data such as traffic, weather, traveler information related to user information.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.3
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• pp.30-36
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• 1993

This paper presents the RAKE receiver over a multipath fading channel. This interference between the propagation paths in a multipath fading causes a serious degradation in the mobile communication environment. In order to derive the path interference and reduce the fading effect, the RAKE receiver is used. As a result, the RAKE receiver gives a better performance than the DS / SS receiver over a multipath fading channel.

• Journal of information and communication convergence engineering
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• v.5 no.4
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• pp.328-332
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• 2007

The structure of MMSE receiver frontended by CMA array working in CDMA forward link is proposed. By using the despreaded pilot signal of forward link as a reference signal, CMA array can capture multi-path signals securely even in severely faded mobile channel. The remaining MAl (Multiple Access Interference) is cancelled by the cascaded MMSE receiver. Through computer simulation, it is proved that the proposed system shows much better BER performance than any other systems. As a mobile based spatio-temporal receiver, the proposed system also reduces implemental cost and complexity by adopting the simplest algorithm for its spatial and temporal domain processing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7A
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• pp.682-687
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• 2010

The IEEE 802.15.4a specification targets the low-rate (LR) Impulse-radio (IR) ultra-wideband (UWB) system which is now widely applied in the WPANs considering rather short distance communications with low complexity and power consumption. The physical (PHY) layer uses concatenated coding with mixed binary phase-shift keying and binary pulse-position modulation (BPSK-BPPM), and direct sequence spreading with time hopping in order that both coherent and non-coherent receiver architectures are supported. In this paper, the performances of multiple access schemes compliant with IEEE 802.15.4a specification are investigated with energy detection receiver, which allow avoiding the complex channel estimation needed by a coherent receiver. However, the performance of energy detection receiver is severely degraded by multi-user interference (MUI), which largely diminishes one of the most fascinating advantages of UWB, namely robustness to MUI as well as the possibility to allow parallel transmissions. So as to improve the performance of multiple access schemes, we propose to apply the novel TH sequences as well as to increase the number of TH positions. The simulation results show that our novel multiple access schemes significantly improve the performance against MUI.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.461-464
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• 2003

This paper explains the impact of frequency error on the performance of WCDMA mobile communication systems and what brings about the frequency error between the base station and the mobile station, and then presents automatic frequency error correction method in mobile receiver. On the basis of system requirement related to frequency stability, the integration test between the base station and the mobile station was accomplished. After applying automatic frequency error correction to mobile receiver, 4 Hz of frequency error at transmitting frequency was obtained. The result met frequency error requirement of 0.1ppm(about 200 Hz). Performance degradation due to frequency error was measured by means of Error Vector Magnitude (EVM)

• International journal of advanced smart convergence
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• v.7 no.2
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• pp.47-54
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• 2018

This paper is a study on implementation of the golf play advice system which provides advice to golfers through mobile devices. The system consists of a mobile unit consisting of a GPS receiver, a data transmitter and receiver, and a display unit, and a server unit composed of a database and advice generator. The advice generator that provides advices to the users, generates advices with IF-THEN rule-based reasoning method. The reasoning module utilizes golfer's personal records and various information in the database of the server unit. This system provides the advice to the users who play on the golf course through mobile devices, so that it is possible to provide various information similar to the screen golf using the computer simulating technology in the outdoor golf course.

• ETRI Journal
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• v.19 no.3
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• pp.116-140
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• 1997

The base station transceiver subsystem (BTS) of the CDMA Mobile System is interfaced to mobile stations over the air and to the wired network through a packet switched interconnection network. The potential benefits of CDMA technology are achieved when the transmitter and the receiver are properly designed and implemented. The physical layer of the interface at the base station is implemented with the CDMA ASICs and control circuits in channel card of the BTS. We present the design perspectives and structural illustration of the BTS. Base station modem ASICs and their control to implement the CDMA receiver, Baseband and RF signal processing blocks, and BTS controller are described. Elaborate power control is essential to ensure the high capacity which is one of advantages of the CDMA technology. The closed loop reverse link power control and the forward link power control operated in the BTS are described.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.97-100
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• 2001

The performance of mobile radio communication system is dependent on various factors such as channel environment. Especially, the number of multipath components of mobile radio channel and multipath delay property in CDMA system for different bandwidths are changed. Therefore, using multipath components, Rake receiver provides improvement of performance of W-CDMA system is evaluated by computer simulation over the types of ITU-R wideband channel model and spreading rate. The result shows that the performance of CDMA adapting RAKE receiver is Improved by the increase of multipath components in equal level of the received power.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.4
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• pp.280-285
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• 2011

Recently, with the development of service robots and the concept of ubiquitous, the position estimation of mobile objects has received great interest. Some of the localization schemes are introduced, which provide the relative location of the moving objects subjected to accumulated errors. To implement a real time localization system, a new absolute position estimation method for a mobile robot in indoor environment is proposed. Design and implementation of the localization system comes from the usage of active beacon systems (based upon RFID technology). The active beacon system is composed of an RFID receiver and an ultra-sonic transmitter. The RFID receiver gets the synchronization signal from the mobile robot and the ultra-sonic transmitter sends out the traveling signal to be used for measuring the distance. Position of a mobile robot in a three dimensional space can be calculated basically from the distance information from three beacons and the absolute position information of the beacons themselves. In some case, the mobile robot can acquire the ultrasonic signals from only one or two beacons, due to the obstacles located along the moving path. In this paper, a position estimation scheme using fewer than three sensors is developed. Also, the extended Kalman filter algorithm is applied for the improvement of position estimation accuracy of the mobile robot.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.6
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• pp.630-637
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• 2003

This paper explains the impact of frequency error on the performance of WCDMA mobile communication systems and what brings about the frequency error between the base station and the mobile station, and then presents automatic frequency error correction method in mobile receiver. On the basis of system requirement related to frequency stability, the integration test between the base station and the mobile station was accomplished. After applying automatic frequency error correction to mobile receiver, 4 Hz of frequency error at transmitting frequency was obtained. The result met frequency error requirement of ${\pm}$0.1 ppm(about ${\pm}$200 ㎐). Performance degradation due to frequency error was measured by means of Error Vector Magnitude(EVM) at transmitter and Ec/Io at receiver, respectively and then the interface requirement between Modem control signal and RF was suggested to improve the correctness of frequency error control.