• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.225-228
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• 2000

In this paper, we present the design of AAL2/AAL5 Type conversion Unit using among BSC, BTS, Core-Network in IMT-2000 system. We first briefly introduce the B-ISDN ATM Adaptation layer specification of Type 2 AAL and Type 5 AAL, and describe conversion flow and each module. And then this paper has designed AAL2/AAL5 Type Conversion Unit and simulated it.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3B
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• pp.209-216
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• 2003

In this paper, we propose ATM switch structure including AAL type 2 switch which can efficiently transmit low-bit rate data, even if the network has many endpoints. We simulate the architecture of ATM switch fabric that is modeled in computer program and analyze the performance according to offered loads. ATM switch proposed in this paper can support cell switching for all types of AAL cells which consist of AAL type 1, AAL type 2, AAL type 3/4, and AAL type 5 cells. We propose two switch fabric methods; One supports the AAL type 2 cell processing per input port, the other global AAL type 2 cell processing for every input port. The simulation results show that the latter is superior to the former. But the former has a merit for easy implementation and extensibility. The proposed ATM switch fabric is widely applicable to mobile communication, narrow band services over ATM network and wireless ATM as well as general ATM switching fabric.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.174-176
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• 2000

AAL2(ATM Adaptation Layer 2)는 짧고 가변 길이를 가지며 지연에 민감한 패킷들을 ATM 상에서 효과적으로 지원하는 프로토콜이다. AAL2 프로토콜은 이동통신망에서의 기지국(BS)과 이동 교환국(MSC) 사이의 중계선 상에서 음성 트래픽을 전송하는데 효과적으로 활용될 수 있다. 본 논문에서는 먼저 AAL2 프로토콜이 다른 AAL 방식에 비해 구별되는 특징을 살펴보고, AAL2의 성능을 시뮬레이션을 통해 분석한다. 그 결과를 토대로 AAL2 프로토콜을 이용한 음성 트래픽 전송망 설계 시에 고려할 요소들을 살펴보고 효과적인 설계 방안을 제시한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.35-43
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• 2004

An AAL2 transmission scheme is used to deliver voice and data traffic between Node-B and RNC on 3G WCDMA network. To predict performance of AAL2 multiplexing precisely, we derived analytically bandwidth gain and cell packing density using discrete-time Markov chain model for voice service and validated these results with simulation. We also performed detailed simulation for AAL2 multiplexing in a concentrator. Based on the analytical result, we propose the engineering guideline to select the optimal Timer_CU in a Node-B. We found that there is no major benefit of additional AAL2 multiplexing in a concentrator and the benefit of AAL2 switching in tub for data services is much less than that for voice service.

• Journal of Internet Computing and Services
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• v.5 no.3
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• pp.45-56
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• 2004

In this paper, we propose ATM switch architecture including ALL type 2 switch which can efficiently transmit low-bit rate data, even if the network has many endpoints. We simulate the architecture of ATM switch fabric that is modeled in computer program and analyze the performance according to offered loads. ATM switch proposed in this paper can support cell switching for all types of m cells which consist of ALL type 1. ALL type 2, ALL type 3/4 and ALL type 5 cells. We propose two switch fabric methods; One supports the ALL type 2 cell processing per input port, the other global ALL type 2 cell processing for every input port. The simulation results show that the latter is superior to the former. But the former has a merit for easy implementation and extensibility. In this paper, the AAL Type 2 switch module which adapts the former method is designed using VHDL language and implemented in FPGA chip. The designed AAL Type 2 switch module operates at 52MHz. The proposed ATM switch fabric is widely applicable to mobile communication, narrow band services over ATM network and wireless ATM as well as general ATM switching fabric.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.9
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• pp.24-29
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• 2000

As a result of the continuing increase in the high capacity and high speed requirement, ATM will be important technology. But previous AAL type cant support service that is variable length, low speed. So AAL2 is the most recently standardized AAL type, which is aimed at providing for the bandwidth efficient transmission of low-rate, short, and variable length packets in delay-sensitive applications. In this paper, we propose the architecture and the behavior of scalable AAL2 switch that are far different from ATM switch. Also, the performance of the designed switch is analyzed by computer simulation.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.159-162
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• 2001

AAL2 is an adaptation layer that is supposed to support delay-sensitive applications with low bit-rate, short, variable packet length in a bandwidth-efficient way. For the switching of AAL2 service channels, AAL2 network is needed, which consists of AAL2 switching nodes. In this paper, The architecture of the unit AAL2 switch is proposed and the performance is analyzed in the CDMA environment.

• Journal of information and communication convergence engineering
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• v.5 no.1
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• pp.23-28
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• 2007

In this paper, we propose ATM switch structure including AAL type 2 switch which can efficiently transmit low-bit rate data, even if the network has many endpoints. We simulate the architecture of ATM switch fabric that is modeled in computer program and analyze the performance according to offered loads. ATM switch proposed in this paper can support cell switching for all types of AAL cells which consist of AAL type 1, AAL type 2, AAL type 3/4, and AAL type 5 cells. We propose two switch fabric methods; One supports the AAL type 2 cell processing per input port, the other global AAL type 2 cell processing for every input port. The simulation results show that the latter is superior to the former. But the former has a strong point for easy implementation and extensibility. The proposed ATM switch fabric architecture is applicable to mobile communication, narrow band services over ATM network.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.1
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• pp.20-33
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• 2002

Usage of ATM AAL2 packets becomes dominant to increase transmission efficiency of voice traffic in the backbone network. In case of voice service that uses AAL2 mechanism, if resources of network are enough, connection of new call is accepted. However, due to packets generated by the new call, transmission delay of packets from old calls can increase sharply. To control this behavior, in this paper we present an AAL2 buffer management scheme that allocates a virtual buffer to each call and after calculating its propagation delay variation(PDV), decides to drop packets coming from each call according to the PDV value. We show that this packet dropping algorithm can effectively prevent abrupt QoS degradation of old calls. To do this, we analyze AAL2 packet composition process to find a critical factor in the process that influences the end-to-end delay behavior and model the process by K-policy M/D/1 queueing system and MIN(K, Tc)-policy M/D/1 queueing system. From the mathematical model, we derive the probability generating function of AAL2 packets in the buffer and mean waiting time of packets in the AAL2 buffer. Analytical results show that the AAL2 packet dropping algorithm can provide stable AAL2 packetization delay and ATM cell generation time even if the number of voice sources increases dramatically. Finally we compare the analytical result to simulation data obtained by using the COMNET Ⅲ package.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8B
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• pp.739-746
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• 2004

An ATM/AAL2 is standardized to transmit delay sensitive application services, which has small size packet, efficiently. An AAL2 transmission scheme is used to deliver voice and data traffic on the lob interface between base station (Node-B) and Radio Network Controller (RNC) in UMTS network. To predict AAL2 performance, a detailed end-to-end UMTS network performance simulator was developed. We performed detailed simulation(cell packing density and bandwidth gain) for voice and data services in UTRAN. The results indicate that the maximum bandwidth gain in Node-B is about 17% and the bandwidth gain of AAL2 multiplexing in $I_{ub}$ for data services is less than that for voice service. Futhermore, the more offered load increase the more the bandwidth gain decreases in a concentrator.