• The Journal of the Korea Contents Association
• /
• v.7 no.3
• /
• pp.60-67
• /
• 2007

This research studies and analyzes the current trends and the frequency allocation bands for digital cordless phone(DCP) in other country. From these results, we propose 1.7GHz & 2.4GHz as a effective candidate frequency band for domestic DCP. A proposed 1.7GHz is expected to introduce DECT system of Europe. Therefore it is necessary to make an analysis of interference between 1.7GHz band and an adjacent IMT-2000 band. In this paper, we proposed the allocation of channel for 1.7GHz on the basis of the analysis of frequency interference between 1.7GHz band and an adjacent IMT-2000 band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.1
• /
• pp.60-67
• /
• 2002

In this paper, the dual band VCO of mobile communication terminal using oscillation part switching circuit is proposed. In order to model the VCO accurately, the resonator is converted the equivalent circuit which is analyzed to use numerical method and designed optimal the dual band VCO operating GSM and DCS band. In order to demonstrate the objective theory of the proposed VCO, the dual band VCO is designed and experimented. The results of experiment, it is conformed that the VCO can be used mobile communication hand phone and components of three generation mobile communication systems.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.3 no.1
• /
• pp.129-139
• /
• 1999

DECT(Digital Enhanced Cordless Telecommunications) is the communication protocol and the pico-cellular network that provides a PABX with mobile services on the local area within its cell radius of about 100 to 200m. Compared with GSM, DECT provides low-cost communication services based on the PSTN and it is an ideal supplementary method for the type of in-building mobile communication. In order to implement the data link communication layer of the DECT system, in this paper we analyzed and designed the structures and functions of it that provided reliable communication and real-time services to the upper network layer by performing the functions of link controls, error controls, sequence controls, and flow controls.

• Proceedings of the Korea Contents Association Conference
• /
• 2006.11a
• /
• pp.52-57
• /
• 2006

This research studies and analyzes the current trends and the frequency allocation bands for digital cordless phone(DCP) in other county. From these results, we propose 1.7GHz & 2.4GHz as a effective candidate frequency band for domestic DCP. A proposed 1.7GHz is expected to introduce DECT system of Europe. Therefore it is necessary to make an analysis of interference between 1.7GHz band and an adjacent IMT-2000 band. In this paper, we proposed the allocation of channel for 1.7GHz on the basis of the analysis of frequency interference between 1.7GHz band and an adjacent IMT-2000 band.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.11a
• /
• pp.356-362
• /
• 1999

DECT(Digital Enhanced Cordless Telecommunications) is the communication protocol and the pico-cellular network that provides a PABX with mobile services on the local area within its cell radius of about 100 to 200m. Compared with GSM, DECT provides low-cost communication services based on the PSTN and it is an ideal supplementary method for the type of in-building mobile communication. In this paper we presented the implementation methods and techniques of the DECT data link communication layer that provided reliable communication services to the upper network layer by performing the functions of link controls, error controls, sequence controls, and flow controls.

• Information and Communications Magazine
• /
• v.14 no.3
• /
• pp.75-86
• /
• 1997

This manuscript describes the high level system design for the DCP system. The DCP HS and BS transceivers are composed of five systems, including the RF/IF unit, the Analog Front End(AFE), the baseband modem, the voice codec and the micro-controller. In the following, the core transceiver architecture with the primary functions at these subsystem is described.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.8
• /
• pp.1349-1355
• /
• 2008

Recently many short-range transceiver systems, such as ZigBee, Bluetooth and RFID(Radio Frequency Identification), have been developed. These systems are mostly low-power transceivers. In the near future many more low-power transceivers are appeared for WPAN(Wireless Personal Area Network) and interference mitigation technologies are necessary to the low-power transceivers for using frequency resources efficiently. In this paper we consider two methods for sharing frequency resources. The first case is that a frequency band previously assigned fer a certain system is shared and the second case is that the white frequency band is shared. We study the method and conditions for sharing frequency resources in the above two cases. When a frequency band is shared with ZigBee, RFID, DCP (Digital Cordless Phone) and Bluetooth as an example for the first case, the sharing conditions are investigated and the results are presented. We propose a balancing factor to maintain an equal transmitting conditions between systems having a different interference mitigation technique. In the interference simulation we use FH(Frequency Hopping) as a reference system and 0.9 of a balancing factor for LBT(Listen Before Talk) and 0.8 for DS(Direct Spreading). From the simulation results we know that a balancing factor reduces interference probability therefore many more systems can be operated in the same frequency bands compared with the case without using a balancing factor.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.18 no.5
• /
• pp.724-729
• /
• 2008

This paper presents the calculation of the required bandwidth of common frequency bandwidth applying queueing theory for maximizing the efficiency of frequency resource of WPAN(Wireless Personal Area Network) based Digital acoustic and communication devices. It assumed that LBT device(ZigBee) and FH devices (DCP, RFID and Bluetooth) coexist in the common frequency band for WPAN based Digital acoustic and communication devices. Frequency hopping (FH) and listen before talk (LBT) have been used for interference avoidance in the short range device (SRD). The LBT system transmits data after searching for usable frequency bandwidth in the radio wave environment. However, the FH system transmits data without searching for usable frequency bandwidth. The queuing theory is employed to model the FH and LBT system, respectively. As a result, the throughput for each channel was analyzed by processing the usage frequency and the interval of service time for each channel statistically. When common frequency bandwidth is shared with SRD using 250mW, it was known that about 35 channels were required at the condition of throughput 84%, which was determined with the input condition of Gaussian distribution implying safety communication. Therefore, the common frequency bandwidth is estimated with multiplying the number of channel by the bandwidth per channel. These methodology will be useful for the efficient usage of frequency bandwidth.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.4
• /
• pp.808-814
• /
• 2007

In this paper, the measurement system of crane moving range is concerned with range recognition technology using phase and magnitude of radio wave. By the proposed technology, we design the radio transmitter and receiver and realize the measurement system, and save the data in disk that is earned from 900Mhz RF signal, middle frequency 450khz of analog signal. As a result of RF measurement, we got 9.3 dBm of RF output and 96 dBc@10khz of phase noise. Range information is earned the data through digital signal processing of IF signal. For the estimation of range measured, we analyze the difference between real range and measurement range, and also suggest the method to remove the measurement error using average processing and amplitude properties. A result is 0.12 and 0.00422 deviation in l0mn-30m and within 5m respectively, and then 2.4E-04 deviation in 4m by using compensation of level characteristics lately.