• Title/Summary/Keyword: dynamic code allocation

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Dynamic code allocation using voice activeity detection in DS-CDMA cellular system (DS-CDMA 셀룰러 시스템에서의 음성검출을 사용한 동적코드할당방식)

  • 유명수;양영님;고종하;이정규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.6
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    • pp.1302-1310
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    • 1997
  • In this paper, we propose a dynamic code allocation strategy using voice activity detection and evaluate the performance of a dynamic code allocation strategy using voice activeity detection in DS-CDMA system. Proposed method allocates code to mobile terminal according to the residual capacity computed by SIR in the base station. In hot spot traffic loading cell, we find that the performance of proposed method is better than that of a fixed code assignment strategy using voice activity detection. Also, we find that the proposed method provide much improvement in blocking probability against the dynamic code assignment strategy withoug voice activity detection.

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New Encoder/Decoder with Wavelength/Time 2-D Codes for Optical CDMA Network (광 부호 분할 다중접속 네트워크를 위한 파장/시간 2차원 코드의 새로운 부호기/복호기)

  • Hwang, Hu-Mor
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.5
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    • pp.1035-1040
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    • 2009
  • We propose a new encoder/decoders based on an tune able wavelength converter(TWC) and an arrayed waveguide grating(AWG) router for large capacity optical CDMA networks. The proposed encoder/decoder treats codewords of wavelength/time 2-D code simultaneously using the dynamic code allocation property of the TWC and the cyclic property of the AWG router, and multiple subscribers can share the encoder/decoder in networks. Feasibility of the structure of the proposed encoder/decoder for dynamic code allocation is tested through simulations using two wavelength/time 2-D codes, which are the generalized multi-wavelength prime code(GMWPC) and the generalized multi-wavelength Reed-Solomon code(GMWRSC). Test results show that the proposed encoder/decoder can increase the channel efficiency not only by increasing the number of simultaneous users without any multiple-access interference but by using a relatively short length CDMA codes.

Shared-type Encoder/Decoder Based on 2-D Optical Codes for Large Capacity Optical CDMA Network (대용량 광 부호 분할 다중접속(Optical CDMA) 네트워크를 위한 2차원 코드의 공유형 부호기/복호기)

  • Ko Wonseok;Shin Seoyong;Hwang Humor;Chang Chulho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.5A
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    • pp.359-369
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    • 2005
  • For large capacity optical CDMA networks, we propose a shared-type encoder/decoders based on an tunable wavelength converter(TWC) and an arrayed waveguide grating (AWG) router. The proposed encoder/decoder treats codewords of wavelength/time 2-D code simultaneously using the dynamic code allocation property of the TWC and the cyclic property of the AWG router, and multiple subscribers can share the encoder/decoder in networks. Feasibility of the structure of the proposed encoder/decoder for dynamic code allocation is tested through simulations using two wavelength/time 2-D codes, which are the generalized multi-wavelength prime code(GMWPC) and the generalized multi-wavelength Reed-Solomon code(GMWRSC). Test results show that the proposed encoder/decoder can increase the channel efficiency not only by increasing the number of simultaneous users without any multiple-access interference but by using a relatively short length CDMA codes.

SIR-based dynamic code allocation method prioritized for handoff call in DS-CDMA cellular system (DS-CDMA 셀룰러 시스템에서 SIR에 기반을 둔 핸드오프 호 우선순위 동적코드할당방식)

  • 이용기;유명수;이정규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.9A
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    • pp.2131-2140
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    • 1998
  • Signal-to-interference ratio (SIR)-based dynamic code allocation method to be rioritized for handoff call is proposed and evaluated in a direct sequence-code division multiple access (DS-CDMA) cellular systm. Proposed method allocates a code to a mobile terminal according to the restidual capacity computed by SIR in the base station. We consider the voice activity detection to increase the system capacity. We evaluate the performance of proposed method with computer simulation. And the handoff decision function that controls handoff of mobile terminal is interodcued. The proposed method provide much improvement in the forced termination probability and handoff call fail probability.

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Selector Processor Allocation Algorithm for Reducing the Call Blocking Rate of Multimedia Service in WCDMA IMT-2000 Systems (비동기 IMT-2000 시스템에서 멀티미디어 서비스 호 차단율 개선을 위한 셀렉터 프로세서 자원할당 방안)

  • Han, Jung-Hee
    • IE interfaces
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    • v.17 no.4
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    • pp.466-471
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    • 2004
  • In this paper, I develop a simple dynamic resource allocation algorithm that reduces the call blocking rate by improving the resource utilization of the WCDMA (Wideband Code Division Multiple Access) systems under multimedia service environment. Simulation results show that the proposed algorithm significantly reduces the blocking rate of high speed multimedia calls. The algorithm developed in this paper is currently working in the commercial WCDMA IMT-2000 system.

A Dynamic Channel Allocation Employing Smart Antenna to Resolve a Crossed Time-slot Problem in TD-SCDMA (TD-SCDMA에서 셀 간 교차 타임-슬롯 문제 해결을 위한 스마트 안테나 기반의 동적 채널 할당 방안)

  • Kim, Eun-Heon;Park, Jae-Hyun;Kim, Duk-Kyung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.12A
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    • pp.1276-1285
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    • 2007
  • Since the TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) system is based on TDD (Time Division Duplexing), the uplink and downlink can be allocated asymmetrically according to the traffic e.g. Web browsing. Although this asymmetric allocation can increase the frequency utilization, it may cause time slot opposing, which implies the time slot is assigned in opposing direction between cells. The time slot opposing can generate significant interference between cells, which results in severe performance degradation. In the paper, a novel dynamic channel allocation (DCA) is proposed in the TD-SCDMA system, to mitigate the impact of time slot opposing considering smart antenna. When the smart antenna is applied in the system, the inter-cell interference is largely affected by beam pattern and beam direction between neighboring cells. Therefore, the time slot opposing and smart antenna should be considered together in the DCA. The intensive simulations show that the proposed scheme can improve the system capacity compared to the conventional DCA schemes.

Dynamic Frame Size Allocation Scheme based on Estimated Number of Tags (태그수추정에 기반한 동적 프레임 크기 할당 기법)

  • Lim, In-Taek
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.3
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    • pp.469-474
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    • 2009
  • An RFID system consists of radio frequency tags attached to objects that need to be identified and one or more electromagnetic readers. Unlike the traditional bar code system, the great benefit of RFID technology is that it allows information to be read without requiring contact between the tag and the reader. For this contact-less feature, RFID technology in the near future will become an attractive alternative to bar code in many application fields. In almost all the 13.56MHz RFID systems, FSA algorithm is used for identifying multiple tags in the reader's identification range. In FSA algorithm, the tag identification time and system efficiency depend mainly on the number of tags and frame size. In this paper, we propose a tag number estimation scheme and a dynamic frame size allocation scheme based on the estimated number of tags.

Performance Evaluations on Shared-Type Encoder/Decoder with Wavelength/Time 2-D Codes for Optical CDMA Networks (파장/시간의 2차원 코드를 사용한 광 부호 분할 다중 접속 부호기/복호기의 성능 분석)

  • Hwang, Hu-Mor;Chang, Chul-Ho;Song, Jin-Ho
    • Proceedings of the KIEE Conference
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    • 2006.07d
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    • pp.2013-2014
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    • 2006
  • For large capacity optical CDMA networks, we propose a shared-type encoder/decoder based on an tunable wavelength conveter (TWC) and an arrayed waveguide grating (AWG) router. Feasibility of the structure of the proposed encoder/decoder for dynamic code allocation is tested through simulations using three types of wavelength/time 2-D codes, which are the generalized multi-wavelength prime code(GMWPC), the generalized multi-wavelength Reed-Solomon code(GMWRSC) and the matrix code. Test results show that the proposed encoder/decoder can increase the channel efficiency not only by increasing the number of simultaneous users without any multiple-access interference but by using a relatively short length CDMA codes.

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A Multi-Dimensional Thermal-Hydraulic System Analysis Code, MARS 1.3.1

  • Jeong, Jae-Jun;Ha, Kwi-Seok;Chung, Bub-Dong;Lee, Won-Jae
    • Nuclear Engineering and Technology
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    • v.31 no.3
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    • pp.344-363
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    • 1999
  • A multi-dimensional thermal-hydraulic system analysis code, MARS 1.3.1, has been developed in order to have the realistic analysis capability of two-phase thermal-hydraulic transients for pressurized water reactor (PWR) plants. As the backbones for the MARS code, the RELAP5/MOD3.2.1.2 and COBRA-TF codes were adopted in order to take advantages of the very general, versatile features of RELAP5 and the realistic three-dimensional hydrodynamic module of COBRA-TF. In the MARS code, all the functional modules of the two codes were unified into a single code first. Then, the source codes were converted into the standard Fortran 90, and then they were restructured using a modular data structure based on "derived type variables" and a new "dynamic memory allocation" scheme. In addition, the Windows features were implemented to improve user friendliness. This paper presents the developmental work of the MARS version 1.3.1 including the hydrodynamic model unification, the heat structure coupling, the code restructuring and modernization, and their verifications.their verifications.

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A New Register Allocation Technique for Performance Enhancement of Embedded Software (내장형 소프트웨어의 성능 향상을 위한 새로운 레지스터 할당 기법)

  • Jong-Yeol, Lee
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.10
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    • pp.85-94
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    • 2004
  • In this paper, a register allocation techlique that translates memory accesses to register accesses Is presented to enhance embedded software performance. In the proposed method, a source code is profiled to generate a memory trace. From the profiling results, target functions with high dynamic call counts are selected, and the proposed register allocation technique is applied only to the target functions to save the compilation time. The memory trace of the target functions is searched for the memory accesses that result in cycle count reduction when replaced by register accesses, and they are translated to register accesses by modifying the intermediate code and allocating Promotion registers. The experiments where the performance is measured in terms of the cycle count on MediaBench and DSPstone benchmark programs show that the proposed method increases the performance by 14% and 18% on the average for ARM and MCORE, respectively.