• Title/Summary/Keyword: Mobile Stations

Search Result 436, Processing Time 0.032 seconds

Economical Approach to Optimal Spectrum Operation in Mobile Networks (경제성을 고려한 이동통신망의 최적 주파수 운용 방안)

  • Yang, Won-Seok
    • Korean Management Science Review
    • /
    • v.27 no.2
    • /
    • pp.21-29
    • /
    • 2010
  • We consider an economic approach for spectrum operations in mobile networks. We present the investment function of base stations according to the number of FAs assuming the linearity of cell splitting. We show that there is an economic amount of spectrum which corresponds to the optimal number of FAs that minimizes the investment. We analyze the impact of the cost structure and the traffic distribution in base stations on the economic amount of spectrum. This paper is applicable to an economic spectrum operation for mobile operators. In addition, the national regulatory authority can use the economic amount of spectrum as the minimal amount for spectrum allocation.

Improvement of Handoff dropping by Separate Queue in Hierarchical Cellular System (계층셀구조에서 계층별 큐를 이용한 핸드오프 강제종료의 개선방안)

  • Kim, Young-il;Seo, Ju-Ha
    • Journal of Industrial Technology
    • /
    • v.22 no.B
    • /
    • pp.175-184
    • /
    • 2002
  • In this paper, we proposed separate queue scheme in each hierarchical cell for effective use of wireless channel. This method reduces the blocking rata of high speed mobile station's handoff in hierarchical cellular systems. Basically for the high speed mobile stations channels are allocated in macrocell and for the low speed mobile stations channels are allocated in microcell. In order to reduce the rate of forced handoff termination, some reservation channels are employed for the fast handoff calls in the macrocells. And the queue is located in each cell to be able to store handoff requests and takeback requests. The overflowed mobile station are able to perform takeback as soon as a corresponding channel is available.

  • PDF

A Multiaceess Protocol for Packet Transmission in Mobile Satellite Systems (이동 위성 통신 시스템에서 패킷 전송을 위한 다원 접속 프로토콜)

  • 임광재;곽경섭
    • Journal of the Korean Institute of Telematics and Electronics A
    • /
    • v.31A no.7
    • /
    • pp.17-28
    • /
    • 1994
  • A combined random/reservation multiple access protocol is proposed which can provide services for packet transmission in mobile satellite systems between mobile statons, or between mobile stations and fixed stations. Random multiple access protocol and reservation multiple access protocol which are currently employed in most satellite communication systems have some strengthes and some weeknesses in according to the kind of user and traffic. In this paper, a combined random/reservation multiple access protocol with better characteristics is proposed. The models of the modified random access protocol and the proposed access protocol is setted and analyzed. The performance of the PDAMA protocol, the random access protocol and the proposed access protocol is compared using simulation. For small packet arrival rate, the performance of the proposed access protocol is close at that of the modified random access protocol, and better than that of the PDAMA protocol. As the packet arrival rate is increased, the modified random access protocol is saturated and unstable at 0.23, and the performance of the proposed access protocol is better than that of the PDAMA protocol.

  • PDF

Performance analysis in location registration schemes in CMS considering mobile power status (이동국의 전원상태를 고려한 CMS 위치등록방식 성능분석)

  • 김광식;조경록
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.21 no.9
    • /
    • pp.2402-2414
    • /
    • 1996
  • Registration is the process by which a base station gets the information of location and status about mobile stations. Registration will become an increasingly important issue in mobile cellular communications, especially in microcellular system with the increase of location updating traffic. Four typesof registration schemes, which are specified in US standard IS-95 and Korean standard TTA-KO-0062, power up registration scheme, power down registration scheme, distance based registration scheme and zone based registration scheme, will be mainly used in the future. In this paper, we derive the combined cost of signaling traffic of paging and registration for various parameters of mobile stations behavior(unencumbered call duration, power up and down rate, velocity, etc.) then we present numerical results for the perfroamnce of four registration schemes. The size of location area is provided for optimal operation.

  • PDF

Uncoordinated Dynamic Frequency Allocation Schemes based on Cognitive Radio in Mobile Cellular Networks (이동셀룰러망에서 무선 인지 기반 비협력 동적 주파수 자원 할당 기법)

  • Yu, Hyun;Jung, Jun-Woo;Lee, Jong-Kwan;Lim, Jae-Sung
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.14 no.5
    • /
    • pp.833-841
    • /
    • 2011
  • In this paper, we propose uncoordinated dynamic frequency(channel) allocation schemes based on cognitive radio in mobile cellular networks(MCNs). Under the assumptions that mobile base stations are equipped with cognitive radio(CR) function and they construct uncoordinated network, the proposed scheme enables the MCNs by suppression of successive channel switching and management of channel allocation in a dynamic and distributed manner. The proposed scheme is composed of two phase processes. In the first phase, highly orthogonal sequences are generated and assigned to mobile base stations. In the second phase, each mobile base station is allocated a channel according to the pre-assigned orthogonal sequences. Simulation results show that the number of successive spectrum switching is reduced significantly compared with the random switching scheme.

Cell Searching and DoA Estimation Techniques for Mobile Relay Stations with a Uniform Linear Array (선형 등간격 어레이를 갖는 이동 릴레이를 위한 셀 탐색 및 입사각 추정 기법)

  • Ko, Yo-Han;Park, Chang-Hwan;Lee, Seung-Jae;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.35 no.6C
    • /
    • pp.530-538
    • /
    • 2010
  • In this paper, estimation methods of cell searching and DoA (Direction of Arrival) for mobile relay stations with a uniform linear array are proposed. The proposed methods can improve the performance of cell searching and DoA estimation by removing the effect of STOs when there exist symbol timing offsets (STOs) between the signals received from adjacent base stations,. Also, the proposed methods can improve the performance of DoA estimation significantly when there exists Doppler frequency shift caused by movement of the mobile relay station. The performances and computational complexities of the proposed cell searching and DoA methods are evaluated by computer simulation under Mobile WiMAX environments.

A Study on MAC Protocol for Packet Data Service in Slotted CDMA Environment (Slotted CDMA 환경에서 패킷 데이터 서비스를 위한 MAC 프로토콜 연구)

  • 임인택
    • Journal of Korea Multimedia Society
    • /
    • v.7 no.2
    • /
    • pp.204-210
    • /
    • 2004
  • This paper proposes a transmission probability control scheme and MAC protocol for packet data services in slotted CDMA system. In slotted CDMA system, multiple access interference is the major factor of unsuccessful packet transmissions. Therefore, in order to obtain the optimal system throughput, the number of simultaneously transmitted packets should be kept at a proper level. In the proposed protocol, the base station calculates the packet transmission probability of mobile stations according to the offered load and then broadcasts it. Mobile stations, which have a packet, attempt to transmit packet with the received probability. Numerical analysis and simulation results show that the proposed scheme can offer better system throughput than the conventional one, and guarantee a good fairness among all mobile stations regardless of the offered load.

  • PDF

Dynamic Backoff Scheme for CDMA-based Packet Radio Networks (CDMA 기반 패킷 무선망에서 동적 백오프 기법)

  • Lim, In-Taek
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • v.9 no.1
    • /
    • pp.561-564
    • /
    • 2005
  • This paper proposes an access control algorithm for guaranteeing fair packet transmissions in CDMA-based slotted ALOHA systems. In the proposed algorithm, the base station calculates the packet transmission and retransmission probabilities based on the offered loads and then broadcasts these probabilities to all mobile stations. Mobile stations, which have a packet to transmit, attempt to transmit a packet with the received probabilities. Simulation results show that the proposed algorithm can offer better system throughput and average delay than the conventional algorithm. Results also show that the proposed algorithm can guarantee a good fairness among all mobile stations regardless of the offered loads.

  • PDF

MAC Protocol for Packet Data Service in Slotted CDMA Environment (슬롯 CDMA 환경에서 패킷 데이터 서비스를 위한 MAC 프로토콜)

  • 임인택
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.7 no.7
    • /
    • pp.1399-1405
    • /
    • 2003
  • This paper proposes an MAC protocol for fair packet data services in stoned CDMA system. In slotted CDMA system, the packets transmitted in the same slot act as multiple access interference, so that unsuccessful packet transmissions are entirely caused by multiple access interference. Therefore, in order to get the optimal system throughput, the number of simultaneously transmitted Packets should be kept at a proper level. In the proposed protocol, the base station calculates the new and retransmitted packet transmission probability of mobile stations according to the offered load and then broadcasts these probabilities. Mobile stations, which have a packet, attempt to transmit packet with the received probabilities. Simulation results show that the proposed scheme can offer better system throughput than the conventional scheme, and guarantee a good fairness among all mobile stations regardless of the offered load.

A Method for monitoring air pollution using base stations (이동통신 기지국을 이용한 대기환경 모니터링)

  • Oh, Hyun-Jung;Lee, Jae-Wook;Baik, Song-Hoon
    • 한국정보통신설비학회:학술대회논문집
    • /
    • 2008.08a
    • /
    • pp.205-208
    • /
    • 2008
  • This article presents a methodology for the monitoring of air pollution. All over the world, the interest in the environment has been continuously increasing. Unfortunately, much of this interest is due to emerging problems, such as the greenhouse effect and climate change. For this reason, research into carbon dioxide, which causes the greenhouse effect, is progressing rapidly. This article presents a method of measuring the level of carbon dioxide and other substances in the air through the utilization of mobile-networking base stations and measured data. First of all, sensors are attached at the appropriate position of the mobile-networking base stations. These sensors will measure the air quality in their respective positions, and send sensor data to an urban management center via network gateways and data-collecting systems. The measured data can be used for various purposes. In general, it can be used to measure the air quality, which can then be used as a basis for urban planning. The method described herein utilizes airpollution sensors that are attached to the base stations in different locations and at varying heights. The data obtained hereby will be applicable in many fields. At this time this is simply a methodology, however we hope that it will lead to a practical application.

  • PDF