차일드 피코넷의 데이터 처리율에 대한 연구

조무호 慶州大學校 2005 論文集 Vol.18 No.2

A piconet is a wireless ad hoc data communications system which allows a number of independent data devices to communicate with each other. A piconet is distinguished from other types of data networks in that communications are normally confined to a small area around person or object whether stationary or in motion that typically covers at least 10 m in all directions. A child piconet is one that is formed under an established piconet. The child piconet functionality is useful for either extending the area of coverage of the piconet or shifting some computational or memory requirements to another PNC capable device. Child piconet is also referred to as dependent piconet since they rely on the parent PNC to allocate channel time for the operation of the dependent piconet. It is possible for the parent piconet to have more than one child piconet. In addition, it is also possible for a child PNC to allow a child piconet as a part of its own piconet. The data throughput of piconet can be affected by these hierarchical formation. In this paper we investigate the data throughput of child piconet by numerical analysis. Results show that child piconet can extend the service coverage as expected. And the child piconet data throughput is increased according to the local traffic. This is due to the closeness of peer to peer communication in child piconet.

[발표 1-4] 클러스터 센서네트워크 라우팅 프로토콜

조무호 한국통신학회 2005 한국통신학회 워크샵 Vol.2005 No.1

WPAN에서 WMN 특허 기술동향 분석

조무호,김광식 경주대학교 정보전자기술연구소 2006 情報電子技術論叢 Vol.5 No.-

In spite of the efforts in researching and developing mobile ad hoc networks in the last decade, this type of network has not yet witnessed mass market deployment. The low commercial penetration of products based on ad hoc networking technology could be explained by noting that the ongoing research is mainly focused on implementing military or specialized civilian applications. On the other hand, users are interested in general-purpose applications where high bandwidth and open access to the Internet are consolidated and cheap commodities. From this user requirements, a new class of networks is started as mesh networks in WPAN(Wireless Personal Network). In this paper we analysis e patents trend of WPAN and estimate future technology progress. And we also investigate the WMN (Wireless Mesh Network) patents which is current emerging technology to improve the radio performance of WPAN. The results of this paper would be a reference document for the researchers and developers who is seraching the related patents in WPAN and WMN.

소프트 핸드오프를 사용하는 시스템에서의 채널 점유시간에 대한 수치 해석

조무호 경주대학교 2001 論文集 Vol.14 No.-

In DS-CDMA (Direct Sequence-Code Division Multiple Access) mobile systems, soft handoff is recognized as reducing interference and increasing reverse link capacity. Whereas from a radio channel resource point of view, soft handoff can make the system performance deteriorate significantly. Mobile stations within a soft handoff region use multiple radio channels and receive their signals from multiple base stations simultaneously. Due to the multiple connections, handoff requests occur more frequently and mobile stations hold longer channel holing time. This paper is focused on the channel holding time distribution of soft handoff systems. The soft handoff rates are estimated by the mobility of mobiles. The channel holding time distribution of the soft handoff traffic model, which does not have a closed-form solution, is derived by a numerical integration method. Computer simulations show promising results based on the non-closed-form application acceptable.

DS-CDMA 셀룰라 시스쳄에서의 소프트 핸드오프율에 대한 분석

조무호,김광식,조경록 한국통신학회 1997 韓國通信學會論文誌 Vol.22 No.8

In DS-CDMA cellular systems, using the same frequency channel at the adjacent cells simultaneously makes soft handoff possible. In soft handoff, mobiles use multiple radio resources for the space diversity of signal in the overlapped region. The previous traffic models of hard handoff are not applicable to the system with soft handoff due to switching radio channels in that region. The handoff rate can be calculated by the mobility of mobiles, which is a function of the size and shape of a cell, and the speed and density of the mobiles. In this paper, we propose an analytical traffic model to study the soft handoff rate. We assume that the system uses a two-way handoff scheme for practical purposes, which connects only two cells to a mobile during soft handoff. We performed a computer simulation to confirm the accuracy of the proposed soft handoff model. The simulation results show good agreement with the analytical model.

이동망 세분화에 대한 연구

조무호 경주대학교 정보전자기술연구소 2002 情報電子技術論叢 Vol.1 No.-

The industry has some urgent issues to resolve in the interconnection between fixed and mobile network, such as introduction of costed based interconnection pricing system. Because of the interconnection way, the profits resulting from the interconnection charges and services can be changed. In the interconnection of all from mobile subscriber to land subscriber (m0bil-to-land), mobile operators route the call with their own network maximum and handover the call to land network near the termination subscriber. They apply the far end havdover method. On the other hand, in the interconnection of call from land subscriber to mobile subscriber (land-to-mobile), land operators handover the call to mobile network. In this case, they use the near end handover method. It is because the land operators do not know about the location of mobile subscribers. Under these unbalanced environment, the costed based interconnection pricing system can make the differences in the profits of interconnection charges between the operators. In this paper, the improvements of land to mobile interconnect system are introduced and the mobile network unbundling is proposed with HLR(Home Location register) access.

소프트 핸드오프 영역이 DS-CDMA 시스템의 블록킹 확률에 미치는 영향 분석

조무호 한국통신학회 2001 韓國通信學會論文誌 Vol.26 No.10

DS-CDMA 이동통신 시스템에서 소프트 핸드오프는 간섭을 감소시켜, 역방향 링크 용량을 증대시키고 통화 절단율을 감소시켜 시스템 성능을 향상시킨다. 반면에 무선 채널 자원 측면에서는 공간 다이버시티를 위해 다수 개의 무선자원을 사용하기 때문에 시스템 성능을 저하시킬 수도 있다. 본 논문에서는 이러한 무선자원 활용 측면에서 DS-CDMA 이동통신 시스템의 소프트 핸드오프에 대한 성능을 분석하였다. 분석 결과에서 무선 채널 자원이 한정된 경우에 소프트 핸드오프 영역이 증가하면 소프트 핸드오프 빈도와 평균 채널 점유시간이 증가하여 채널 블록킹율을 상당하게 증가시키는 것을 확인할 수 있었다. 핸드오프 영역이 증가되기 전과 동일한 블록킹율을 유지시키기 위해서는 증가되는 영역에 비례하여 추가적인 무선 채널 자원이 제공되어야 한다.

클러스터 트리 센서 네트워크 성능 분석

조무호,남윤석,최은창,허재두 한국인터넷정보학회 2004 인터넷정보학회지 Vol.5 No.4

WPAN 피코넷 자동 구성에 대한 연구

조무호,Cho, Moo-Ho 한국조명전기설비학회 2005 조명·전기설비학회논문지 Vol.19 No.7

WPAN(Wireless Personal Area Networks)에서는 현재 동작중인 PNC(Piconet Coordinator)가 피코넷을 떠나거나 종료하고자 할 때, 피코넷 내의 PNC 능력을 가진 디바이스에게 PNC 역할을 양도할 수 있다. 그러나 WPAN의 권고안에서는 PNC 핸드오버를 위한 PNC 후보 선택에 대해서는 디바이스 성능 정보를 비교하여 선택하는 방안만을 기술되어 있으며, 이에 대한 구체적인 선택 방법은 포함하고 있지 않다. 본 논문에서는 피코넷 NC가 피코넷 내의 다른 디바이스에게 PNC 기능을 양도하게 될 때에 피코넷의 데이터 처리성능을 최적화 될 수 있게 PNC 수용 디바이스 개수와 밀집도를 고려하여 PNC를 선택하는 방안에 대해 제안한다. 수치 해석의 결과에서 보면 디바이스들이 집중되어 있을수록 평균 데이터 처리량이 증가되는 것을 나타내었고, 최고 두 배까지 향상되었다. 따라서 PNC 후보 선발시 서비스 디바이스 개수와 밀집도를 같이 고려해야만 피코넷 성능을 높일 수 있다. If the PNC is shutting down or wants to leave the WPAN, it uses the handover process to give control to another device in the piconet. However when the PNC is selected, only the device capability information is checked in the WPAN standard specification and no detail criteria is described. In this paper, the PNC selection method with considering the number and density of device to maximize the piconet data throughput in the WPAN is studied. From the numerical analysis results, the considering with the devices concentration has higher data throughput compared with the uniform distribution. For the efficient performance, the device distribution within the piconet should be considered in the PNC selection.

스마트워크 도입 기업의 IT자원이 직무성과에 미치는 영향에 관한 실증연구 : 집단지성의 매개효과를 중심으로

조무호,양동우 한국디지털정책학회 2017 디지털융복합연구 Vol.15 No.8