• Title/Summary/Keyword: Dedicated Channel

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Analysis of Channel Access Delay in CR-MAC Protocol for Ad Hoc Cognitive Radio Wireless Sensor Networks without a Common Control Channel

  • Joshi, Gyanendra Prasad;Nam, Seung Yeob;Acharya, Srijana;Kim, Sung Won
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.3
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    • pp.911-923
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    • 2014
  • Ad hoc cognitive radio wireless sensor networks allow secondary wireless sensor nodes to recognize spectrum opportunities and transmit data. Most existing protocols proposed for ad hoc cognitive radio wireless sensor networks require a dedicated common control channel. Allocating one channel just for control packet exchange is a waste of resources for channel-constrained networks. There are very few protocols that do not rely on a common control channel and that exchange channel-negotiation control packets during a pre-allocated time on the data channels. This, however, can require a substantial amount of time to access the channel when an incumbent is present on the channel, where the nodes are intended to negotiate for the data channel. This study examined channel access delay on cognitive radio wireless sensor networks that have no dedicated common control channel.

Performance Analysis of Dedicated Short Range Communication System on the Rician Fading Channel (라이시안 페이딩 환경에서 단거리전용통신(DSRC) 시스템의 성능 분석)

  • Kim, Man-Ho;Kang, Heau-Jo
    • Journal of Advanced Navigation Technology
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    • v.10 no.1
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    • pp.7-12
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    • 2006
  • In this paper, we investigated performance for 5.8GHz dedicated short range communication system using OFDM which will be applied to Intelligent transportation system services. The maximum speed of a vehicle in DSRC channel is very fast as 180km/h, so a service time is very short to serve a various traffic information if hand-off is not occurred. Therefore higher bit rate is required to proved advanced and intelligent service to the drivers of various vehicle and the data transmission rate of the next generation DSRC system if being promoted over 10Mbps. The signals received in Racian channel have been simulated using the computer simulator. For performance improvement, BCH coding scheme are adopted.

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A Channel Allocation Method on Cellular Systems with Multimedia Traffic (멀티미디어 환경하의 계층구조 이동통신 시스템에서의 채널할당방법)

  • Kim, Jeong-Kee;Hur, Sun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.22 no.51
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    • pp.89-97
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    • 1999
  • Recently, due to the rapid technological progress, CDMA cellular system is widely used for voice, data and multimedia services. But the analysis for voice-data integrated traffic has not been done satisfactorily. Moreover, there is few research results for voice-data integrated traffic. In this paper, we propose an effective channel allocation algorithm for CDMA cellular system which serves voice-data integrated traffic. As for the proposed channel allocation algorithm, new calls and hand-off calls first attempt to connect micro-cell. We model the channel allocating scheme as a Birth-and-Death process. We reserve a few hand-off dedicated channels and calculate the blocking probability of hand-off calls varying the number of hand-off dedicated channels. Then we decide the number of hand-off dedicated channels satisfying the proper QoS(Quality of Service) and minimum blocking probability.

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PERFORMANCE ANALYSIS OF COGNITIVE NETWORK WITH PRIMARY AND SECONDARY CHANNELS

  • Lee, Yutae
    • East Asian mathematical journal
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    • v.29 no.1
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    • pp.101-107
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    • 2013
  • We consider a cognitive network with a primary and a secondary channel. Primary users have higher priority on the usage of the primary channel, and secondary users are allowed to opportunistically access the primary channel at times when the channel is not occupied by primary users. The secondary channel is dedicated only to secondary users. An analytical model is presented to obtain the performance of an opportunistic spectrum access using both the primary and secondary channels, and is validated by simulations.

A New Counting Scheme for MBS in WiBro (WiBro MBS상에서의 새로운 Counting Scheme)

  • Sung, Nag-Bum;Kim, Kyung-Tae;Youn, Hee-Yong
    • The KIPS Transactions:PartC
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    • v.15C no.4
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    • pp.263-272
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    • 2008
  • Recently, WiBro has been developed to efficiently support real-time broadcasting with wireless system. MBS (Multicast Broadcast Service) based on WiBro has numerous applications such as DMB. Since the current MBS uses only common channel managed by scheduling, it cannot effectively support many users at the same time. This paper proposes a new counting scheme with which the channel mode can be properly switched between common channel and dedicated channel. It thus allows efficient use of limited radio resource in WiBro for the MBS.

Performance Improvement of the Tx Diversity for W-CDMA (W-CDMA를 위한 전송 안테나 다이버시티 성능 개선)

  • 김성진;이용석;박형운
    • Proceedings of the IEEK Conference
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    • 2000.09a
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    • pp.87-90
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    • 2000
  • Differential channel 정보를 feedback 하는 close loop Tx diversity를 제안한다. 본 Tx diversity는 기존의 channel feedback Tx diversity 보다 W-CDMA의 forward link와 reverse link channel 용량을 더 많이 늘린다. Differential channel 정보를 estimation 하는 방법을 제안한다. 부가적으로 보내는 정보 없이 W-CDMA의 forward power control 에 사용하는 dedicated pilot 심볼을 이용해 differential channel 정보를 estimation한다. 기존에 제안된 channel feedback Tx diversity들과 성능을 비교한다.

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Performance Evaluation of the Common Channel Access Method in CDMA Packet Service System (CDMA 패킷 서비스 시스템에서 Common Channel Access 방법의 성능 평가)

  • Lee, Kang-Won
    • IE interfaces
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    • v.17 no.3
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    • pp.294-304
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    • 2004
  • In the IS-95 packet service system, the radio channels are generally classified into the dedicated and common traffic channels. In this paper, the performance of the common traffic channel access method is evaluated using simulation. The simulation results are compared with those of random access method. Simulation results show that the capacity can be increased up to 25% by applying the proposed common channel access method. The delay problem and variance of BER are also discussed.

Channel Access Control Method for the CDMA Packet Service System (CDMA 패킷 서비스 시스템에서 채널 엑세스 제어 기법 연구)

  • 이강원
    • Journal of the Korean Operations Research and Management Science Society
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    • v.28 no.3
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    • pp.169-184
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    • 2003
  • In the IS-95 packet service system, the radio channels are generally classified into the dedicated and the common traffic channels. In this paper, a common traffic channel access method is proposed for the COMA packet service system to enhance the radio resource utilization while guaranteeing QoS to the users. The proposed method is based on the permission probability for the common traffic channel user. To derive permission probability, optimization models are developed for two different QoS constraints. Approximation methods are also developed.

Implementation of viterbi Decoder for IMT2000 Mobile Station in FPGA form (IMT2000 단말기용 Viterbi Decoder의 FPGA 구현)

  • 김진일;정완용;김동현;정건필;조춘식
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.825-828
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    • 1999
  • A Viterbi Decoder for IMT2000 Mobile Station based on cdma200 is implemented in this paper. There are fundamental traffic channel, supplemental traffic channel for user data transmission and dedicated control channel for signal transmission in cdma2000. This decoder can decode these channels simultaneously, and support l/2, l/3, 1/4 code rate decoding. In case of fundamental channel decoding, it needs about 1100 logic cells and 30000 bit memory block.

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A Survey on Multiple Channel protocols for Ad Hoc Wireless Networks

  • Su, Xin;Shin, Seokjoo;Chung, Ilyong
    • Proceedings of the Korea Information Processing Society Conference
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    • 2009.04a
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    • pp.842-845
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    • 2009
  • Wireless ad hoc networks often suffer from rapidly degrading performance with the number of user increases in the network. One of the major reasons for this rapid degradation of performance is the fact that users are sharing a single channel. Obviously, the problem of using single shared channel schemes is that the probability of collision increases with the number of nodes. Fortunately, it is possible to solve this problem with multi-channel approaches. Due to the especial properties of multiple channels, using the multiple channels is more efficient than single channel because it enhances the capacity of the channel and reduces the error rate during data transmission. Some multi-channel schemes us one dedicated channel for control packets and one separate channel for data transmissions. On the other hand, another protocols use more than two channels for data transmissions. This paper summarizes six multiple channel protocols based on these two kinds of schemes. Then we compare them and discuss the research challenge of multiple channel protocols.