2003 IEEE Pacific Rim Conference on Communications Computers and Signal Processing (PACRIM 2003) (Cat. No.03CH37490)
ABSTRACT This paper focuses on an analysis of an orthogonal-variable-spreading-factor (OVSF) code... more ABSTRACT This paper focuses on an analysis of an orthogonal-variable-spreading-factor (OVSF) codes assignment scheme called the hybrid OVSF-code assignment (HCA). We propose HCA as an alternative solution for OVSF code assignment in order to mitigate so-called code blocking in OVSF-CDMA and to correspond to each service equally. We present the performance evaluation of HCA by computer simulations.
2008 7th Asia-Pacific Symposium on Information and Telecommunication Technologies, 2008
ABSTRACT Stream control transmission protocol (SCTP) is a transport layer protocol for the next-g... more ABSTRACT Stream control transmission protocol (SCTP) is a transport layer protocol for the next-generation Internet. In this paper, we investigate optimally condition for MPEG 4 video communication with SCTP in 802.11 wireless access media. We focus on the multi-streaming feature and the partial reliability extension in SCTP and compare performance of MPEG4 video quality under the policy w th/without differentiated retransmission among streams. Differentiated policy allows packets belonging to a specific stream to be retransmitted, while packets are transmitted exactly one time (no retransmissions) in homogeneous policy. By computer simulation, we show that SCTP can (1) improve the video quality by exploiting the multi-streaming and partial reliability features, and (2) enhance the video transmission quality can by adjusting SCTP fast retransmit threshold.
2009 IEEE 20th International Symposium on Personal, Indoor and Mobile Radio Communications, 2009
In this paper, we introduce an extension of Stream Control transmission Protocol (SCTP) aiming fo... more In this paper, we introduce an extension of Stream Control transmission Protocol (SCTP) aiming for improving the efficiency of delay-sensitive transmission of multimedia data such MPEG-4 traffic. Briefly, our SCTP extension exploits one-way delay between SCTP endpoints, which allows the SCTP extension to retransmit lost packets selectively depending on whether the lost packets would still arrive before the schedule time. By computer simulations, we show that our extension provides the better performance than a simple retransmission method based on lifetime under both wired and wireless access links. Specifically, we confirm that our extension maintains the fair sharing of bandwidth among the legacy TCP flows, irrelevant to wired and wireless access links.
The 2nd IEEE Asia-Pacific Service Computing Conference (APSCC 2007), 2007
ABSTRACT The stream control transmission protocol (SCTP) is a reliable transport layer protocol s... more ABSTRACT The stream control transmission protocol (SCTP) is a reliable transport layer protocol standardized by IETF as RFC 2960 in 2000. Because of its attractive features such as multi-homing and multi-streaming, SCTP has received much attention from researchers in worldwide with an expectation that would address limitations of TCP performance encountered in wired-cum-wireless networks. In this paper, we focus on the multi-streaming feature of SCTP. Making use of the partial reliability extension in SCTP, we compare performance of MPEG-4 video quality under the policy with/without differentiated retransmission among streams. Differentiated policy allows packets belonging to a specific stream to be retransmitted, while packets are transmitted exactly one time (no retransmissions) in homogeneous policy. We show by simulation, that video object traffic streams encoded by MPEG-4 can be efficiently conveyed under lossy link by SCTP with differentiated policy among streams than with homogeneous policy. We further analyze and show, also by simulation, that SCTP with optimally tuned retransmission policy can minimize the play- out delay time as well as keep high quality video decoding of MPEG-4 traffic stream.
This paper focuses on an analysis of an orthogonal-variable-spreading-factor (OVSF) codes assignm... more This paper focuses on an analysis of an orthogonal-variable-spreading-factor (OVSF) codes assignment scheme called the hybrid OVSF-code assignment (HCA). We propose HCA as an alternative solution for OVSF code assignment in order to mitigate so-called code blocking in OVSF-CDMA and to correspond to each service equally. We present the performance evaluation of HCA by computer simulations.
... Minn and Siu proposed the dynamic OVSF-code ... A.2 Voice Terminal A voice source in which th... more ... Minn and Siu proposed the dynamic OVSF-code ... A.2 Voice Terminal A voice source in which the pattern of talkspurts and silence gaps is generated by the means of a Slow Speech Activitgl Detector is considered [4]. It can be modeled as a two state Markov chain as shown in Fig ...
This paper compares the performance of the orthogonal-variable-spreading-factor (OVSF) code assig... more This paper compares the performance of the orthogonal-variable-spreading-factor (OVSF) code assignment schemes based on UMTS/IMT-2000 proposed so far, i.e., the conventional code assignment scheme (CONV), the dynamic code assignment scheme (DCA), and region division assignment scheme (RDA). It was shown that RDA gives better performance than DCA and CONV in terms of the packet dropping probability under heavy traffic conditions. In this paper, we make extensive performance comparisons among the three proposed OVSF code assignment schemes. We focus on two performance measures, i.e., the number of simultaneous voice conversations and the calculation time. The simulation results show that the calculation time of RDA is significantly lower than that of DCA. RDA can simultaneously handle much more voice sources than DCA.
2003 IEEE Pacific Rim Conference on Communications Computers and Signal Processing (PACRIM 2003) (Cat. No.03CH37490)
ABSTRACT This paper focuses on an analysis of an orthogonal-variable-spreading-factor (OVSF) code... more ABSTRACT This paper focuses on an analysis of an orthogonal-variable-spreading-factor (OVSF) codes assignment scheme called the hybrid OVSF-code assignment (HCA). We propose HCA as an alternative solution for OVSF code assignment in order to mitigate so-called code blocking in OVSF-CDMA and to correspond to each service equally. We present the performance evaluation of HCA by computer simulations.
2008 7th Asia-Pacific Symposium on Information and Telecommunication Technologies, 2008
ABSTRACT Stream control transmission protocol (SCTP) is a transport layer protocol for the next-g... more ABSTRACT Stream control transmission protocol (SCTP) is a transport layer protocol for the next-generation Internet. In this paper, we investigate optimally condition for MPEG 4 video communication with SCTP in 802.11 wireless access media. We focus on the multi-streaming feature and the partial reliability extension in SCTP and compare performance of MPEG4 video quality under the policy w th/without differentiated retransmission among streams. Differentiated policy allows packets belonging to a specific stream to be retransmitted, while packets are transmitted exactly one time (no retransmissions) in homogeneous policy. By computer simulation, we show that SCTP can (1) improve the video quality by exploiting the multi-streaming and partial reliability features, and (2) enhance the video transmission quality can by adjusting SCTP fast retransmit threshold.
2009 IEEE 20th International Symposium on Personal, Indoor and Mobile Radio Communications, 2009
In this paper, we introduce an extension of Stream Control transmission Protocol (SCTP) aiming fo... more In this paper, we introduce an extension of Stream Control transmission Protocol (SCTP) aiming for improving the efficiency of delay-sensitive transmission of multimedia data such MPEG-4 traffic. Briefly, our SCTP extension exploits one-way delay between SCTP endpoints, which allows the SCTP extension to retransmit lost packets selectively depending on whether the lost packets would still arrive before the schedule time. By computer simulations, we show that our extension provides the better performance than a simple retransmission method based on lifetime under both wired and wireless access links. Specifically, we confirm that our extension maintains the fair sharing of bandwidth among the legacy TCP flows, irrelevant to wired and wireless access links.
The 2nd IEEE Asia-Pacific Service Computing Conference (APSCC 2007), 2007
ABSTRACT The stream control transmission protocol (SCTP) is a reliable transport layer protocol s... more ABSTRACT The stream control transmission protocol (SCTP) is a reliable transport layer protocol standardized by IETF as RFC 2960 in 2000. Because of its attractive features such as multi-homing and multi-streaming, SCTP has received much attention from researchers in worldwide with an expectation that would address limitations of TCP performance encountered in wired-cum-wireless networks. In this paper, we focus on the multi-streaming feature of SCTP. Making use of the partial reliability extension in SCTP, we compare performance of MPEG-4 video quality under the policy with/without differentiated retransmission among streams. Differentiated policy allows packets belonging to a specific stream to be retransmitted, while packets are transmitted exactly one time (no retransmissions) in homogeneous policy. We show by simulation, that video object traffic streams encoded by MPEG-4 can be efficiently conveyed under lossy link by SCTP with differentiated policy among streams than with homogeneous policy. We further analyze and show, also by simulation, that SCTP with optimally tuned retransmission policy can minimize the play- out delay time as well as keep high quality video decoding of MPEG-4 traffic stream.
This paper focuses on an analysis of an orthogonal-variable-spreading-factor (OVSF) codes assignm... more This paper focuses on an analysis of an orthogonal-variable-spreading-factor (OVSF) codes assignment scheme called the hybrid OVSF-code assignment (HCA). We propose HCA as an alternative solution for OVSF code assignment in order to mitigate so-called code blocking in OVSF-CDMA and to correspond to each service equally. We present the performance evaluation of HCA by computer simulations.
... Minn and Siu proposed the dynamic OVSF-code ... A.2 Voice Terminal A voice source in which th... more ... Minn and Siu proposed the dynamic OVSF-code ... A.2 Voice Terminal A voice source in which the pattern of talkspurts and silence gaps is generated by the means of a Slow Speech Activitgl Detector is considered [4]. It can be modeled as a two state Markov chain as shown in Fig ...
This paper compares the performance of the orthogonal-variable-spreading-factor (OVSF) code assig... more This paper compares the performance of the orthogonal-variable-spreading-factor (OVSF) code assignment schemes based on UMTS/IMT-2000 proposed so far, i.e., the conventional code assignment scheme (CONV), the dynamic code assignment scheme (DCA), and region division assignment scheme (RDA). It was shown that RDA gives better performance than DCA and CONV in terms of the packet dropping probability under heavy traffic conditions. In this paper, we make extensive performance comparisons among the three proposed OVSF code assignment schemes. We focus on two performance measures, i.e., the number of simultaneous voice conversations and the calculation time. The simulation results show that the calculation time of RDA is significantly lower than that of DCA. RDA can simultaneously handle much more voice sources than DCA.
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Papers by K. Kawanishi