2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2017
Coping with the limited amount of available spectrum, time division duplexing (TDD) system is con... more Coping with the limited amount of available spectrum, time division duplexing (TDD) system is considered as an attractive duplexing method due to exploiting channel reciprocity as well as flexible resource management. The conventional scheduling scheme is based on the channel quality indicator (CQI) reported from the user equipment (UE) to estimate instantaneous data rates for the scheduling metric calculation. However, CQI is insufficient to reflect the state of the channel variation in terms of frequency and time. Based on the channel reciprocity of TDD systems, we utilize uplink sounding reference signal (SRS) to estimate downlink channel status. However the received SRS power is a result of uplink power control where power control effect should be compensated to estimate channel status in downlink scheduling. In order to solve this problem, we propose the SRS path loss estimation method based on the power headroom report. By using this scheme, the base station (BS) can obtain th...
2019 IEEE VTS Asia Pacific Wireless Communications Symposium (APWCS), 2019
Ultra-Dense Network is considered as a 5G / B5G network environment, which is a method of increas... more Ultra-Dense Network is considered as a 5G / B5G network environment, which is a method of increasing network capacity by greatly increasing the density of small base stations. In the UDN network environment, the deployment of numerous base stations causes a problem of inter-cell interference, and also an efficient frequency resource allocation should be considered. In order to manage efficient frequency resources, a clustering method, which is a method of managing a lot of base stations as a unit, is introduced. Resource management for clustering is greatly depending on the number of clusters to be set up, such as the number of small base stations per cluster and the location of the center point. According to the number of clusters, the inter-cell interference between clusters and frequency reuse factor are evaluated and the optimal number of clusters is analyzed in the given UDN environment that achieves the maximum capacity. As a result, the maximum capacity is achieved when the number of clusters in the UDN environment is around 13, and it is found that the operating frequency band (channel characteristics) has the greatest effect on an optimal number of clusters.
Fifth Asia-Pacific Conference on ... and Fourth Optoelectronics and Communications Conference on Communications,, 1999
ABSTRACT The performance of reverse link synchronous DS-CDMA cellular networks in a Rayleigh mult... more ABSTRACT The performance of reverse link synchronous DS-CDMA cellular networks in a Rayleigh multipath fading channel is analyzed to investigate the effect of other cells interference. It is shown that the capacity of synchronous transmission is still larger than asynchronous transmission, even if the effect of the other cells interference is considered
VTC '98. 48th IEEE Vehicular Technology Conference. Pathway to Global Wireless Revolution (Cat. No.98CH36151)
ABSTRACT Inter-cell asynchronous DS-CDMA systems were proposed for third-generation mobile system... more ABSTRACT Inter-cell asynchronous DS-CDMA systems were proposed for third-generation mobile systems, and many research studies on this system are in progress. An inter-cell asynchronous mode DS-CDMA system using a two-pilot structure was proposed by Hong, Lee, Yang, Ahn and (see IEEE ICUPC'96, vol.2, p.365-8, 1996) for flexible cell deployment. In the system, a cell site transmits two pilots, a cluster and a cell pilot, and the cell search is performed by two steps to decrease the cell search time. In this paper, a practical cell structure and cell search algorithm based on the two-pilot scheme of Hong et al. are described, and the performance of the cell search algorithm is evaluated by computer simulations. The results shows that over than 90% of the cell search can be completed within about 600 ms when 512 cell pilot codes of 40960 chip length is used
The 7th International Conference on Advanced Communication Technology, 2005, ICACT 2005., 2005
MIMO system (multiple antennas at the transmitter and receiver) is capable of very high theoretic... more MIMO system (multiple antennas at the transmitter and receiver) is capable of very high theoretical capacities. As an important space-time code, V-BLAST (vertical-Bell lab layered space-time) code has been researched recently. The important operation of V-BLAST system is cancellation. However the conventional detection algorithm requires time to execute linear combination nulling and successive symbol cancellation. The time delay enhanced if the number of transmit antennas increase. In order to avoid this obstacle, parallel symbol cancellation (PSC) was proposed. But the performance is degraded. In this paper, we propose a combination of SSC and PSC to improve the system performance
Page 1. Effect of Line-of-Sight on Dual-Hop Nonregenerative Relay Wireless Communications Trung Q... more Page 1. Effect of Line-of-Sight on Dual-Hop Nonregenerative Relay Wireless Communications Trung Q. Duong, Hyundong Shin, Een-Kee Hong School of Electronics and Information, Kyung Hee University, Korea e-mail: {dqtrung, hshin, ekhong}@khu.ac.kr ...
Proceedings of ICUPC - 5th International Conference on Universal Personal Communications
ABSTRACT The radio characteristics and an overview of a personal communication system under devel... more ABSTRACT The radio characteristics and an overview of a personal communication system under development at Korea Mobile Telecom (KMT) are introduced with emphasis on the intercell asynchronous mode and synchronous transmission in the reverse link. We present two pilot schemes as an approach for the intercell asynchronous mode. In addition, the effects of synchronous transmission in the reverse link and code multiplexing for a data service with high data rates are considered
Proceedings of Vehicular Technology Conference - VTC
Abstract We address the use of wideband CDMA technology for the next generation mobile telecommun... more Abstract We address the use of wideband CDMA technology for the next generation mobile telecommunications service. The radio characteristics and an overview of a personal communication system operating in the 1.885-2.025 GHz band) under development at ...
2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2017
Coping with the limited amount of available spectrum, time division duplexing (TDD) system is con... more Coping with the limited amount of available spectrum, time division duplexing (TDD) system is considered as an attractive duplexing method due to exploiting channel reciprocity as well as flexible resource management. The conventional scheduling scheme is based on the channel quality indicator (CQI) reported from the user equipment (UE) to estimate instantaneous data rates for the scheduling metric calculation. However, CQI is insufficient to reflect the state of the channel variation in terms of frequency and time. Based on the channel reciprocity of TDD systems, we utilize uplink sounding reference signal (SRS) to estimate downlink channel status. However the received SRS power is a result of uplink power control where power control effect should be compensated to estimate channel status in downlink scheduling. In order to solve this problem, we propose the SRS path loss estimation method based on the power headroom report. By using this scheme, the base station (BS) can obtain th...
2019 IEEE VTS Asia Pacific Wireless Communications Symposium (APWCS), 2019
Ultra-Dense Network is considered as a 5G / B5G network environment, which is a method of increas... more Ultra-Dense Network is considered as a 5G / B5G network environment, which is a method of increasing network capacity by greatly increasing the density of small base stations. In the UDN network environment, the deployment of numerous base stations causes a problem of inter-cell interference, and also an efficient frequency resource allocation should be considered. In order to manage efficient frequency resources, a clustering method, which is a method of managing a lot of base stations as a unit, is introduced. Resource management for clustering is greatly depending on the number of clusters to be set up, such as the number of small base stations per cluster and the location of the center point. According to the number of clusters, the inter-cell interference between clusters and frequency reuse factor are evaluated and the optimal number of clusters is analyzed in the given UDN environment that achieves the maximum capacity. As a result, the maximum capacity is achieved when the number of clusters in the UDN environment is around 13, and it is found that the operating frequency band (channel characteristics) has the greatest effect on an optimal number of clusters.
Fifth Asia-Pacific Conference on ... and Fourth Optoelectronics and Communications Conference on Communications,, 1999
ABSTRACT The performance of reverse link synchronous DS-CDMA cellular networks in a Rayleigh mult... more ABSTRACT The performance of reverse link synchronous DS-CDMA cellular networks in a Rayleigh multipath fading channel is analyzed to investigate the effect of other cells interference. It is shown that the capacity of synchronous transmission is still larger than asynchronous transmission, even if the effect of the other cells interference is considered
VTC '98. 48th IEEE Vehicular Technology Conference. Pathway to Global Wireless Revolution (Cat. No.98CH36151)
ABSTRACT Inter-cell asynchronous DS-CDMA systems were proposed for third-generation mobile system... more ABSTRACT Inter-cell asynchronous DS-CDMA systems were proposed for third-generation mobile systems, and many research studies on this system are in progress. An inter-cell asynchronous mode DS-CDMA system using a two-pilot structure was proposed by Hong, Lee, Yang, Ahn and (see IEEE ICUPC'96, vol.2, p.365-8, 1996) for flexible cell deployment. In the system, a cell site transmits two pilots, a cluster and a cell pilot, and the cell search is performed by two steps to decrease the cell search time. In this paper, a practical cell structure and cell search algorithm based on the two-pilot scheme of Hong et al. are described, and the performance of the cell search algorithm is evaluated by computer simulations. The results shows that over than 90% of the cell search can be completed within about 600 ms when 512 cell pilot codes of 40960 chip length is used
The 7th International Conference on Advanced Communication Technology, 2005, ICACT 2005., 2005
MIMO system (multiple antennas at the transmitter and receiver) is capable of very high theoretic... more MIMO system (multiple antennas at the transmitter and receiver) is capable of very high theoretical capacities. As an important space-time code, V-BLAST (vertical-Bell lab layered space-time) code has been researched recently. The important operation of V-BLAST system is cancellation. However the conventional detection algorithm requires time to execute linear combination nulling and successive symbol cancellation. The time delay enhanced if the number of transmit antennas increase. In order to avoid this obstacle, parallel symbol cancellation (PSC) was proposed. But the performance is degraded. In this paper, we propose a combination of SSC and PSC to improve the system performance
Page 1. Effect of Line-of-Sight on Dual-Hop Nonregenerative Relay Wireless Communications Trung Q... more Page 1. Effect of Line-of-Sight on Dual-Hop Nonregenerative Relay Wireless Communications Trung Q. Duong, Hyundong Shin, Een-Kee Hong School of Electronics and Information, Kyung Hee University, Korea e-mail: {dqtrung, hshin, ekhong}@khu.ac.kr ...
Proceedings of ICUPC - 5th International Conference on Universal Personal Communications
ABSTRACT The radio characteristics and an overview of a personal communication system under devel... more ABSTRACT The radio characteristics and an overview of a personal communication system under development at Korea Mobile Telecom (KMT) are introduced with emphasis on the intercell asynchronous mode and synchronous transmission in the reverse link. We present two pilot schemes as an approach for the intercell asynchronous mode. In addition, the effects of synchronous transmission in the reverse link and code multiplexing for a data service with high data rates are considered
Proceedings of Vehicular Technology Conference - VTC
Abstract We address the use of wideband CDMA technology for the next generation mobile telecommun... more Abstract We address the use of wideband CDMA technology for the next generation mobile telecommunications service. The radio characteristics and an overview of a personal communication system operating in the 1.885-2.025 GHz band) under development at ...
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