HSDPA 서비스 수용 및 사용의도의 영향요인에 관한 실증적 연구

이준엽 韓國外國語大學校 大學院 2009 국내박사

ABSTRACT Korea holds the steadfast status as a global leader in the field of information technology, though it was late in the industrialization. Especially in the information communication technology, it has made repeated rapid growth with the global standardization of national technologies such as WiBro and DMB, and with success in the world's first commercialization of CDMA. The number of subscribers to mobile communication services has been greatly increasing, affected by the government's activation policy focused on network investments, intense promotion strategy of the late-starters, sales promotion of handled device subsidies, etc. HSDP service, which has begun nationwide network service since the year 2007, will be expected to take the lead hereafter in the national mobile service technologies. But the ARPU from HSDP has not greatly increased, despite of the rapid increase in subscribers to HSDPA service. The understanding of the reason that the increase in the subscription to HSDPA service doesn't result in the increase in its use is important for the national brand image as 'IT Strong Power Korea' as well as to each individual service provider. The purpose of this study is to examine the factors affecting the intention to adopt and the intention to use HSDPA, the new 3.5 generation communication service, and to analyze the relation between the two intentions, based on previous studies on the technology acceptance. This study is built on the research design with the following research questions. First, what is the factor affecting HSDPA service adoption? Secondly, what is the factor affecting HSDPA service use intention? And third, there is the significant difference between the service adoption and the actual use, and what is the relation between the two intentions? The hypotheses for this study are as follows. H1a: The more experienced an individual is in using wireless mobile communication service, the more significant positive effect it will have on the adoption intention. H1b: The more experienced an individual is in using wireless mobile communication service, the more significant positive effect it will have on the use intention. H1c: The more innovative an individual is, the more significant positive effect it will have on the adoption intention. H1d: The more innovative an individual is, the more significant positive effect it will have on the use intention. H1e: The more self-efficacious an individual is, the more significant positive effect it will have on the adoption intention. H1f: The more self-efficacious an individual is, the more significant positive effect it will have on the use intention. H2a: The less service cost an individual perceives, the more significant positive effect it will have on the adoption intention. H2b: The less service cost an individual perceives, the more significant positive effect it will have on the use intention. H2c: The more subsidy an individual perceives, the more significant positive effect it will have on the adoption intention. H2d: The more subsidy an individual perceives, the more significant positive effect it will have on the use intention. H3: The service adoption will have a significant positive effect on the use intention. The results of questionnaires executed from April 30, 2009 to May 14, 2009 verified the research hypotheses based on the research design. The 264 well answered data among total of 266 surveys were chosen for analysis with unsuitable two answers excluded. The data got through regression analysis and multiple discriminant analysis by the program SPSS(ver. 16.0). The results of the verification of hypotheses in this study are as follows. Accepted are hypothesis H1a that the more experienced in using service, the more significant positive effect on the adoption intention, hypothesis H1c that the more innovative, the more significant positive effect on the adoption intention, hypothesis H2a that the less service cost perceived, the more significant positive effect on the adoption intention, and hypothesis H2c that the more subsidy perceived, the more significant positive effect on the adoption intention. But rejected is hypothesis H1e that the more self-efficacious, the more significant positive effect on the adoption intention. Accepted are hypothesis H1b that the more experienced in using service, the more significant positive effect on the use intention, hypothesis H1f that the more self-efficacious, the more significant positive effect on the use intention, and hypothesis H2b that the less service cost perceived, the more significant positive effect on the use intention. But rejected are hypothesis H1d that the more innovative, the more significant positive effect on the use intention, and hypothesis H2c that the more subsidy perceived, the more significant positive effect on the adoption intention. And accepted is hypothesis H3 that the service adoption will have a positive effect on the use intention. The meaning and suggestion of this study are as follows. First, this study classifies apart the factor affecting the adoption intention and that affecting the use intention, while most of existing studies have usually dealt with the intention to adopt the new mobile communication service. This study is significant in inducing customers' active use based on the result from examining the difference between the factors affecting HSDPA service adoption and use intention, and analyzing the relation between the two intentions from various angles. Secondly, this study provides the framework for segmenting customers of the HSDPA service market. It classifies customers into four groups according to the high and low of the adoption intention and use intention, and examines the adoption intention factor and the use intention factor of each group. This basis of classifying groups is significant in providing future mobile communication providers with the framework for market segmentation. Third, this study examines the effect the subsidy has on the market. The research results show that the handled device subsidy have little effect on actual service use, though it is positive in speeding up HSDPA service diffusion in a short term, because it appears to affect only the adoption intention. They suggest that the subsidy is no more effective help to service providers in more urgent need to increase ARPU than to increase adopters, while it is an effective strategy for late starters increasing adopters. Forth, perceived service cost proves to be a factor affecting both adoption intention and use intention, which suggests the need of service goods of various costs and bundling goods, with elasticity of service cost for mobile communication demand, of income, and of substitution with the wire telephone into consideration. And fifth, the multiple discriminant analysis was applied for estimating the group which new measuring objects will belong to. And the result is significant in estimating the group according to the strength of the adoption intention and use intention of customers newly adopting HSDPA service. The research assignment for this study to take hereafter is as follows. First, it is necessary to research other external variables in addition to individual characteristics and media cost variable affecting HSDPA service adoption and use intention. Secondly, it is necessary to examine the wider range of sample, considering the present trend of HSDPA service extension. This study excludes from the sample teenage users, one axis of HSDPA service users. And third, it is possible to suggest the result from understanding of changing causality under longitudinal research, considering the speed of mobile communication growth.

Packet scheduler를 통한 QoS와 HSDPA 전송완료율 개선에 관한 연구

김상주 연세대학교 공학대학원 2007 국내석사

This study suggests the method to improve QoS (Quality of Service) and Transmission Complete rate of wireless-internet service by designing adaptive Scheduler with the types of packet service in HSDPA.High-speed data transmission of HSDPA depends on the number of users and the service types provided to them in one cell. A base station allocates the channel power to numbers of people using voice call, media service, and low-speed data service with limited wired/wireless resources, and then allots the rest of power to HS-PDSCH. When users request the services in a good wireless-environment (good CQI), a base station allocates low power to their data channels, which causes less effect to the other people using any other type of services. On the other hand, relatively higher channel power is supposed to be allocated to users located in a bad wireless-environment, which brings about the worse Ec/Io and reduction of coverage in its cell. In other words, HSDPA Scheduler may bring about negative influence to the services or cause insufficient QoS to the users in a bad environment because the characteristics of services are not considered in HSDPA Scheduler.This paper suggests new scheduler by categorizing the various types of wireless-internet services and their using-pattern in HSDPA. Furthermore, service-adaptive (SA) packet scheduler is designed with consideration of QoS depending on the types of services, the amount of packet usages and holding time for services. Therefore, this new SA scheduler with several additional factors suggested in this paper may give rise to more efficient allocation of limited resources and guarantee satisfactory QoS to a large numbers of users. 본 논문은 HSDPA망에서 제공하는 Packet Service 호의 유형별 특성을 고려한 서비스 적응형 Scheduler 설계로, 무선인터넷호의 QoS (Quality of Service) 완료율 개선 방법을 제안 하였다.HSDPA를 통한 고속하향 Data 서비스는 동일 Cell 내 다른 서비스 사용자의 서비스 형태와 부하량에 의하여 영향을 받는다. 따라서 기지국은 제한된 유/무선 자원 범위 내에서 음성, 영상 또는 저속data 사용자에 Channel Power를 할당하고 고속하향 Data 서비스를 위한 HS-PDSCH 에 나머지 잉여 Power를 할당하게 된다. 그러나, HSDPA 서비스를 요청하는 UE가 무선환경(CQI)이 양호한 환경에 있을 경우에는 고속하향 Data Channel 에 낮은 Power를 할당하므로 다른 서비스 제공자에게 영향이 적으나, 무선환경이 불량한 구간에서는 잉여 Power 범위 내에서 Channel Power를 상승시켜야 하므로 Cell Power가 제한되는 경우에는 Cell 내부의 Ec/Io를 열화시켜 Coverage 축소를 야기 시킬 수 있다. 즉, HSDPA Scheduler는 서비스 호의 유형별 특성을 고려 하지 않고 기지국의 모든 잉여자원을 Scheduling에 할당하므로 다수의 Packet서비스 요구 발생시 기타형태의 서비스 호에 부정적 영향을 주거나, 무선환경이 양호하지 못한 가입자에게는 QoS제공이 불가하게 된다.이를 개선하고자 본 논문에서는 HSDPA에서 제공하는 다양한 형태의 무선Data 서비스 호를 유형별로 분류하고, Type별 사용행태를 정리함으로써 Data 호에 대한 예측 Scheduling 방식을 제안하였으며, 나아가 서비스 Type에 따른 QoS, Packet 사용량, 예상 접속유지 시간 등을 추가로 고려한 능동적 형태의 서비스 적응형(SA) Packet Scheduler 를 설계하였다. SA Scheduler 적용을 통하여 기지국의 불필요한 자원할당을 줄이고, 다수의 고속Data 사용자에 만족할 QoS를 제공할 수 있을 것이다.

HSDPA 휴대전화의 사용의도에 영향을 미치는 요인

김종국 韓國外國語大學校 經營大學院 2007 국내석사

본 연구는 HSDPA 휴대전화의 사용의도에 미치는 영향요인을 이론적, 실증적으로 분석한 논문이다. HSDPA 휴대전화에 대한 기존 연구의 대부분이 정책이나 기술 그리고 긍정적인 면에 초점을 맞추어 연구가 이루어졌다. 이에 따라 HSDPA의 휴대전화의 사용의도에 직접적으로 영향을 미치는 긍정적 요인과 혁신 저항적요인에 관한 연구가 전무하다는 문제 인식에서 분 연구를 시작하였다. 본 연구는 확장된 기술 수용 모델과 혁신 저항모델의 문헌 연구에서 독립 변수를 추출하였고, 사용의도를 종속 변수로 하여 가설을 수립하였다. 자료분석은 다중회귀분석 방법을 이용하여 분석하였다. 연구 결과 지각된 유용성, 지각된 사용용이성, 혁신 제품의 특징, 지각된 재미, 더 좋은 제품 기대는 채택되었고, 지각된 자기효능, 복잡성, 지각된 위험, 기존제품 태도는 기각되었다. 향후 연구에서는 HSDPA 휴대전화가 더 확산되어진 시점에서 다른 산업간의 융합과의 측면을 고려한 실증 연구가 이루어져야 할 것이다.

(A) new soft handover mechanism using DCHs in high-speed downlink packet access networks

이태훈 Graduate School, Yonsei University 2009 국내석사

3GPP (Third Generation Partnership Project) Release 5 (R5)에서 WCDMA 네트워크 위에서 다운링크 패킷 전송률을 향상시킨 HSDPA (High Speed-Downlink Packet Access)가 정의되었다. HSDPA는 HS-DSCHs (High Speed-Downlink Shared Channels)를 통해 10 Mbps의 데이터 전송률을 지원하지만, HSDPA 표준은 소프트 핸드오버를 지원하지 않기 때문에 UE (User Equipment)는 상대적으로 긴 핸드오버 딜레이를 가지게 된다. 그러므로 이 논문에서는 HS-DSCH대신 DCH (Dedicated Channel)를 사용하여 핸드오버 딜레이를 줄이는 새로운 소프트 핸드오버 기술을 제안한다. 제안하는 소프트 핸드오버 기술은 패킷 간의 상호 도착 시간 (Inter Arrival Time, IAT)이 15 msec 이하이며, 반면에 HSDPA 표준인 하드 핸드오버는 패킷 IAT가 190 msec임을 시뮬레이션 결과를 통해 보여준다. 이는 제안하는 기술이 전형적인 VoIP서비스가 최고의 품질로 제공되기 위해서는 패킷간 IAT가 20 msec 이하여야 한다는 조건을 충족한다. 게다가 제안하는 기술은 UE가 소프트 핸드오버를 수행하는 동안 데이터의 연결성이 방해 받지 않게 해준다.The first 3GPP (Third Generation Partnership Project) WCDMA (Wideband Code Division Multiple Access) networks were launched during 2002. Currently, the WCDMA networks are deployed in UMTS (UniversalMobile Telecommunications System) band around 2GHz in Europe and Asia including Korea and Japan. 3GPP has defined the WCDMA operation for several additional bands, which are expected to be taken into use during the coming years. In 3GPP Release 5 (R5), HSDPA (High-Speed Downlink Packet Access) has been standardized to enhance the data rate of downlink packet transmission on top of WCDMA network. HSDPA was standardized as part of 3GPP R5 with the first specification version in March 2002. HSUPA (High-Speed Uplink Packet Access) was part of 3GPP Release 6 (R6) with the first specification version in December 2004. HSDPA and HSUPA together are called 'HSPA' (High-Speed Packet Access). Even HSDPA supports up to 10 Mbps data rate through HS-DSCHs (High Speed-Downlink Shared Channels), an UE (User Equipment) suffers from significant handover latency since HSDPA standard does not supporting soft handover~\cite{conf/vtc/lunden}\cite{conf/vtc/wang}. Therefore, in this paper, we propose a new soft handover mechanism for HSDPA to reduce the handover latency by utilizing DCH (Dedicated Channel) instead of HS-DSCH. Simulation results show the proposed soft handover mechanism reduces the packet IAT (Inter Arrival Time) less than 15 msec while HSDPA's hard handover suffers from 190 msec packet IAT. It means that the proposed mechanism guarantees the minimum packet IAT requirement of the typical VoIP service in 20 msec. Furthermore, the proposed mechanism employees no service disruption for the data connection while an UE performs the soft handover procedure.

무선인터넷 기반의 무인선박 제어에 관한 연구

김효일 한국해양대학교 대학원 2011 국내석사

Unmanned system has been introduced to many fields. In the beginning, the majority of the system consisted of simple and repetitive automation technology that can perform tasks that are difficult or dangerous for human. Recently, however, other systems such as unmanned car, aircraft, submarine, ship have been researched and developed thanks to the advancement of technology. Google, the world's largest Internet searching company, has developed unmanned car and succeeded in test running. As can be seen here, unmanned system technology is ubiquitous in our reality. So far, researches on unmanned system have been mostly performed at national level for military purposes or by some universities due to high development cost. However, the fact that such researches have been performed by commercial enterprises such as Google implies that the unmanned system technology will be commercialized before long. Meanwhile, researches on USV are behind those on other unmanned systems, and Korea is no exception. However, surveys on market forecasts of USV indicate that such researches are urgent. First, American market forecast agency, Visiongain, estimated in 2008 that the market size of USV in 2009 will amount $160 million. Secondly, Moire Inc. estimated in 2003 that the market size in 2011 will be about 300 ships and $1.8 billion. Finally, the most recent survey performed by Research And Markets in 2010 estimated that the market size for the next decade (2010-2019) will range from 1,144 ships ($2.3 billion) to 1,870 ships ($3.8 billion). Altogether, this has been the background for our research on USV. When USV carries out its mission at sea, every action including status check is taken by radio communication. Thus, selecting an appropriate means of radio communication is a crucial step. So far, VHF and/or UHF communication modem have been used for controlling USV, which need a separate operation console. Also, their communication range is greatly affected by antenna height, which decreases the mobility of control station and increases the development cost. Thus, in this study, I would like to develop 'wireless Internet-based USV' that can communicate without such operation console and used for surveillance of major shore facilities and observation of marine environment. Control station will move the USV connected via wireless Internet to desired position. At the same time, the ship will transmit the data gathered by equipped camera and sensors to the station to enable real-time monitoring. In order to develop such wireless Internet-based USV, we have applied wireless Internet service that has a globally established standard for communication and commercially available. Wireless Internet services that are currently available in Korea are WLAN with IEEE 802.11 b, g, n standards, WiBro (Mobile WiMax) with IEEE 802.16e standard and HSDPA that uses 3.5-th generation mobile radio communication network. WLAN is theoretically very fast (54Mbps) but has a very small coverage of 100m, and the lack of hand-over feature is its major weakness. WiBro has hand-over feature and can be used while moving, but its theoretical coverage is still limited to 1km. On the other hand, HSDPA has rather slow (theoretical) download speed of 14.4Mbps but a wide coverage as it uses mobile radio communication network. Meanwhile, in order to apply HSPDA wireless to USV, it is necessary to figure out its actual Internet speed and service coverage at sea. For this, I have performed quality test of HSDPA wireless Internet during anchoring and navigation. As a result, the average download speed and average upload speed were 4.87KB/sec and 6.05KB/sec, respectively. Also, ping test result showed that both download and upload were free of data delay or loss, indicating that the data transmission was slow but very stable. Another interesting fact was that, although I had expected before test that Internet speed would depend on distance, the actual speed of HSDPA did not differ very much depending on distance. It is important to note that upload speed is more important than download speed in operating USV. The data sent from control station to USV are text data that do not exceed 1KB, so the average download speed of 4.87KB is more than enough. However, data from various sensors such as GPS and camera image should be transmitted from the ship to the station, and the camera image data far exceed the average upload speed of 6.05KB. Thus, when designing communication program for USV, image size and transmission interval of image data should be considered. In this study, I have set the image size to be 105 x 75 pixels and the interval to be 3 sec. to resolve this problem. Although I could verify the potential of HSDPA wireless Internet in controlling USV, it is thought to be more or less slow to be commercialized. However, once the 4th-generation mobile communication, LTE (Long Term Evolution) is commercialized, theoretical speed of HSDPA will increase by about 12 times. Moreover, the Ministry of Land, Transport and Maritime Affairs as well as 3 major telecom companies have been installing 45 mobile communication repeaters in coastal areas, islands and lighthouses since 2008, and have made an agreement that they will further install repeaters in 49 lighthouses until 2013 so that mobile phones can be used within distance of 30~50km. This will, in turn, increase the coverage of HSDPA. Thus, control of USV by HSDPA is thought to be practical in Korea's territorial waters. Another feature of this study, along with the use of wireless Internet, is autonomous navigation. The goal of USV is not only to protect people from marine danger but also to save cost. Thus, USV without autonomous navigation feature does not have much economic profit compared to manned ship, as it should be monitored and controlled by someone at the control station. In this study, autonomous navigation is that the control station sets the waypoints of the ship through Internet, compares the ship position gathered by GPS and true course obtained from waypoint to heading gathered by heading sensor and enter it to controller, which will then autonomously adjust the rudder angle and navigate toward the waypoint. In this study, in order to implement autonomous navigation, I have assumed the unmanned ship as discrete system and used ARX model (Autoregressive model with eXternal input) as linear I/O model of the discrete system. For estimating parameters of ARX model, I have used rudder angle () and turning circle angular speed () data that were gathered from the ship's turning circle test. Also, digital PID controller was applied to discrete system for autonomous navigation of the ship. Designing a digital PID controller requires (Proportional Gain), (Integral Time) and (Derivative Time), which were determined by Z-N tuning method. The wireless Internet-based USV was then successfully verified by actual tests at sea.

HSDPA의 HS-SCCH 전력 조정을 통한 Throughput 향상 방안

김진수 경북대학교 산업대학원 2011 국내석사

In this thesis, a novel technology to increase the throughput of the HSPDA service by optimizing the channel power of the the High-Speed Downlink Shared Channel (HS-DSCH). The shared channel transmission has been implemented in WCDMA by using HS-CSCH which enables the rapid allocation of a large fraction of downlink resources for data transmission to a specific user. The HS-DSCH uses the total remaining power after serving other power-controlled channels such as common channels. To improve throughput for downloading data, it's necessary to have more power for HS-DSCH. In this paper, HS-SCCH optimization is used to get the extra power. The measurement of the Channel Quality Indicator(CQI) shows that the channel power control algorithm can increase the throughput of the channel. HSDPA의 전력 할당 알고리즘은 WCDMA의 각 채널에서 사용하고 남은 여분의 전력을 전부 사용하는 구조로 다른 채널의 최적화를 통하여 여분의 파워를 얻을 수 있다면 HS-PDSCH로 좀 더 많은 전력을 할당할 수 있어 Throughput 향상을 기대할 수 있다. 본 논문에서는 HS-SCCH의 전력 할당을 줄여 여분의 전력을 얻고 이를 HS-PDSCH에 사용하게 함으로써 Data Throughput 향상시킬 수 있는지를 시험하고자 하였다. HSDPA에서 HS-SCCH는 HS-PDSCH의 전송에 사용된 정보가 포함되는 채널로 데이터 전송에 있어서 아주 중요한 역할을 하는 채널이다. 따라서 너무 작은 값을 사용하였을 경우 필요한 정보를 전달할 수 없어 품질에 열화가 생기고 너무 많은 값을 사용할 경우 HS-PDSCH에 할당 가능한 전력이 줄어들어 Data Throughput의 향상을 기대할 수 없을 것이다. 본문의 실험에서는 상용 망에서 제조사의 기본 값인 9dB와 개선 예상 값인 5dB와의 값에 대한 Throughput 변화와 CQI(Channel Quality Indicator) 변화를 측정하였다.

HSDPA를 이용한 무인항공기 항법 모니터링용 Peer-to-Peer 통신 시스템 구현 및 활용방안에 관한 연구

김호균 부산대학교 2012 국내석사

본 논문은 상용 HSDPA(High Speed Downlink Packet Access)이동통신 모뎀을 이용한 무인항공기 항법 모니터링용 Peer-to-Peer 통신시스템 구현에 대하여 연구 하였다. 본 시스템은 통신 중계용 서버, 탑재통신 장비 및 다수의 모니터링 장치로 구성되며, 상용 HSDPA 모뎀을 이용하여 무인항공기 항법정보를 서버를 통하여 다수의 모니터링 장치로 실시간 전송한다. 본 논문에서는 이러한 시스템에서 발생할 수 있는 현상들을 관찰 하고자 지상실험 및 비행실험을 통해 데이터를 확보 하였다. 실험 결과, 통신환경에 따라 탑재통신장치와 모니터링 장치 사이의 지연시간이 평균 약 300msec 가량 측정 되었으며, 탑재통신장치와 서버간의 데이터의 체증(congestion) 및 패킷 손실이 발생 하였지만, 차량을 이용한 고속 장거리 이동 테스트, 무인기 비행을 통한 고도 테스트를 통하여 무인기 항법 모니터링 시스템 구현이 가능함을 확인 하였다. This paper presents a realization of a peer-to-peer communication system for a UAV navigational monitoring using a commercial HSDPA(High Speed Download Packet Access) mobile communication device. The realized system consists of a communication server, an air data terminal and multiple ground monitoring devices, where the server transfers navigational data from a UAV to multiple monitoring devices in real-time with commercial HSDPA modem. Through ground and flight tests, data were obtained to observe the realized system. The tests results found about 300 msec delay, congestion, packet-loss depending on communication environment between air data terminal and ground monitoring devices. Nevertheless, through high-speed long range test on a ground vehicle and altitude test with a UAV flight, the feasibility of a UAV navigational monitoring system was observed.

고속 이동통신 시스템에서 음성 서비스를 위한 하향링크 스케줄링 기술

김주한 세종대학교 대학원 2011 국내석사

본 논문은 고속 이동통신 시스템에서 음성 서비스 지원을 위한 하향링크 스케줄링 기술에 초점을 두고 있다. 특히, 음성 서비스의 전력할당 방식을 주 대상으로 하고 있다. 따라서 음성 서비스의 전력할당 방식을 제안하고, 음성 서비스의 전송효율 향상을 확인하고자 한다. 제안한 전력할당 방식의 성능을 위해 셀 반경, 음성 용량측면을 측정하였다. 고속 이동통신 시스템에서 음성 서비스 지원은 1개의 채널코드만으로 충분 한다. 그러나 고속 이동통신 시스템은 하향링크로 전송되는 각 채널 코드의 전력제어를 하지 않는다. 다시 말해서, 각 채널 코드는 동일한 전송전력을 가지게 된다. 그렇기 때문에 기지국은 음성 패킷 을 전송할 때 단말의 채널상태를 고려하지 않고 동일한 전송전력을 할당해주는 비효율적인 스케줄링을 실행하게 된다. 따라서 이러한 문제를 보완하기 위해 단말의 채널상태를 고려한 전력할당 방식을 제안하고자 한다. 음성 서비스의 전력할당 방식은 2가지 방안을 제안하였다. 1) 기준이 되는 target CQI를 설정한 후 기준보다 낮은 CQI를 갖는 단말의 전력 값을 기준 전력 값으로 재조정해준다. 2) target CQI값 외에 allocation CQI 추가로 설정한 후, target CQI와 allocation CQI 사이에 값을 가지는 단말에게 추가로 전력을 할당해준다. 시뮬레이션을 위해 NS-2 네트워크 시뮬레이터를 사용했으며, HSDPA 환경에서 음성 서비스를 지원하기 위해서 eurane 패치를 한 후 수정하였다. 시뮬레이션은 제안하는 전력할당 방식에서 셀 반경과 단말 수를 변경하면서 성능을 측정하였다. 제안한 방법과 결과를 비교하기 위해서 기존의 시스템은 HS-SCCH less 방식으로 동작한다고 가정하였다. 시뮬레이션 결과를 보면, 음성 서비스 전송의 성능향상을 볼 수 있다. HS-SCCH less 방식으로 동작하는 기존 시스템에서는 약 120명의 음성 단말을 지원할 수 있지만, 1) 방안을 적용하면 target CQI 6 기준으로 약 21%의 성능 향상을 보였다. 2)번 방안 역시 기준 값 대비 10% 이상씩의 향상을 보였다. 이러한 결과로 볼 때, 제안한 음성 서비스의 전력할당 방식이 기존의 방법 보다 효율적이라는 것을 알 수 있다. 결론적으로 음성 서비스 단말의 전력 재할당 방안은 실시간 서비스인 음성 서비스 전송효율을 높인다고 볼 수 있다. The thesis focus in the downlink scheduling algorithm for voice services in high-speed mobile communication systems. In particular, transmission power allocation method of voice services is the main object. Therefor, I suggest the power reallocation method of voice services and confirm the transmission efficiency of the voice service. For the performance of the proposed scheme, I measure cell radius and voice capacity aspects. High-speed mobile communication systems support voice services from a single channel code should be sufficient. However, high-speed mobile communications system not perform the downlink power control for transferred to each channel code. In other words, each channel code will have the same transmission power. As a result, the Node B will be ineffective scheduling. Because, Node B send voice packets to the terminal without considering the status of the channel and assigns the same transmission power. Therefore, to complement the scheduling problem, considering the state of terminal channel power reallocation scheme is proposed. For voice service, two kinds of power allocation scheme is proposed. 1) after setting a target CQI which is standard values, power values of Ue with lower CQI than the target CQI re-enables. 2) In addition to target CQI value is set to add after the allocation CQI, target CQI and allocation CQI has a value between the terminals allocated to allow additional power. NS-2 network simulator for the simulation were used. For supporting voice services in HSDPA, Eurane patch were used and it modified. I supposed the existing system to work by a HS-SCCH less operation method to compare a result with the method that I suggested. Simulation results show a performance enhancement of the transmission of voice services. The existing system working by a HS-SCCH less operation method can support about around 120 voice terminals. But, power reallocation method 1) shows about 21% performance enhancements and 2) present about 10% performance enhancements in target CQI 6 standards. These results show that the proposed power reallocation method of voice service is more efficient than existing methods can be seen that. In conclusion, the power reallocation of voice terminal would improve the transmission efficiency.

HSDPA의 투자 가치 평가에 관한 연구 : 실물 옵션 접근법으로

이태희 연세대학교 정보대학원 2007 국내석사

현재 국내 이동통신 시장은 가입자가 이미 4천만 명에 육박하면서 포화상태에 이르렀다. 그 결과 이동통신사들의 성장도 한계점에 다다르고 있다. 이에 따라 이동통신들은 새로운 기술 및 서비스 도입을 통해 돌파구를 마련하고 있으며 현재 활발히 진행되고 있는 3세대 이동통신(3G)으로의 이동이 이러한 노력의 하나라고 볼 수 있다.전통적인 평가방법인 현금흐름할인법(DCF)는 불확실성이 높은 환경에서 관리의 유연성으로 발생할 수 있는 의사결정의 전략적 가치를 적절하게 반영하지 못하고 있다. 본 연구는 실물 옵션이론을 이용하여 HSDPA의 투자가치를 분석함으로써 미래의 불확실성을 가치 평가에 반영함으로써 좀 더 적절한 가치평가를 시도하였다.본 연구에서는 3세대 이동통신의 가치를 실물 옵션 접근법을 이용하여 평가해 봄으로써 현재 진행되고 있는 3세대 이동통신에 대한 투자가 절절한 수준에서 이루어지고 있는지에 대해 판단하며 이를 통해 우리나라의 이동통신 정책에 대한 시사점을 논의하였다. While investment in the IT industry generates high value added, it involves not only uncertainty and variability but also enormous investment. Subsequently, failure might cause considerable losses. Under such circumstances, it is necessary to reflect upon the strategic values of decision making that can occur with managerial flexibility. This study evaluates values in investing WCDMA/HSDPA - the technologies selected in Korea in the process of evolving third-generationmobile telecommunication. It took advantage of real option approach, which enables consideration of the uncertainty of the IT industry. As a result, this study determines whether the ongoing investment in third-generation mobile telecommunication has been carried out, and suggests implications for mobile telecommunication in our country.

HSDPA시스템에서 수신 SIR기반의 능동적 채널 할당 방식의 공평한 스케줄링 기법에 관한 연구

이승환 영남대학교 대학원 2007 국내석사