This letter mathematically proves that the performance of the new protocol in Ref. [1] is better than that of the existing protocol. It was proposed that a frame from an access device is delivered over the access link and then it is multiplexed and packed into ATM cell at an access node and then the cell is carried toward a voice gateway, by using a method to split two sublayers in AAL2. That means one sublayer is implemented at the subscriber access device and the other sublayer is implemented at the access node. Access devices using the protocol achieve higher utilization of CID and waste fewer ATM resource per the access device. Mathematical analysis is performed on the proposed and existing protocol, and both upstream cell rate and padding probability are calculated. The proposed protocol shows lower upstream traffic rate and padding cell probability than the existing protocol.

This letter proposes that by separating the two sublayers within AAL2 for VoDSL, a non-ATM-based IAD at customer premises can support AAL2 service through a DSLAM including new functions at the central office. To achieve this goal, AAL2 SSCS for bearer channels is located at the CPE. Also, AAL2 CPS and AAL2 SSCS for frame mode service including SSSAR and SSTED are located at the DSLAM. By doing so, one endpoint of an ATM connection at the customer side moves to the DSLAM. All bearer channels, CAS or CCS signaling and DSS1 relay messages from the customer side are transmitted to voice gateway transparently. As a result, the ATM connection using AAL2 can multiplex CPS packets from more AAL2 users, which improves multiplexing gain, minimizes waiting probability, and significantly decreases the number of cells into ATM networks. The simulation shows that the proposed method results in less ATM traffic and padded cell ratio, compared with the existing method.

AAL2 technology, which will be used in 3rd generation mobile communications systems, can be used to efficiently transmit low-bit-rate traffic. Because user connections are multiplexed at virtual-channel connections in AAL2 networks, conventional ATM QoS management, which operates in units of VC connections, may be inadequate for managing the QoS of AAL2 connections. In this paper, we argue that for efficient utilization of network resources, it is advantageous to accommodate AAL2 connections with different QoS conditions in the same VC connection. We present a multiplexing configuration that enables QoS to be controlled at the AAL2-connection level. It works by matching the AAL2-packet-multiplexing timing to the cell-transmission timing. We also address the issue of AAL2-bandwidth management. To calculate the bandwidth, we evaluate the characteristics of multiplexing CPS packets into the ATM cell payload.

This paper investigates the effectiveness of a network that uses unspecified bit rate (UBR) for a virtual channel (VC) accommodating AAL2 connections. AAL2 is a new ATM adaptation layer that has recently been standardized. Since it is designed to carry low-bit-rate voice signals efficiently, it should be used in the ATM backbone for mobile networks, especially in the IMT-2000 network (International Mobile Telecommunication in the Year 2000 network). Normally, constant-bit-rate (CBR) VCs or variable-bit-rate (VBR) VCs are used to accommodate AAL2 connections. In our previous work, however, we showed that using UBR VCs (equivalent to no VC-level bandwidth management) to accommodate AAL2 connections needs much less VP bandwidth than using CBR or VBR VCs. In this paper, the previous results are extended to the network and the network bandwidth reduction is shown to be larger than that of the virtual path. In addition, the bandwidth reduction achieved by using UBR VCs is comparable with that achieved by introducing AAL2 switching nodes. Based on these results, the core network of the IMT-2000 is discussed.

For vacuum-UV (VUV) phosphor application such as plasma display panels (PDPs) and mercury free lamps, CaAl2O4:Eu2+ (CA:Eu2+) showing 440 nm blue emission was examined. A single phase CA:Eu2+ was obtained by two step firing technique. The photoluminescence (PL) spectrum shows blue shift compared to that of blue-emitting BaMgAl10O17:Eu2+ (BAM:Eu2+) phosphors. CA:Eu2+ phosphors with β-tridymite crystal structure show less luminance degradation on baking in comparison to the commercial BAM:Eu2+ phosphors under VUV excitation. The initial PL intensity of CA:Eu2+ (Eu: 2 mol%) powder phosphor excited by 147 nm light was found to be about 60% of the commercial BAM:Eu2+ and the luminance of test panel with CA:Eu2+ (Eu: 1 mol%) was 37.4 cd/m2. The low test panel luminance with CA:Eu2+ phosphor is partly caused by the poor spread characteristics of the phosphor slurry due to the large particle size distribution. With improvement of luminance efficiency and the powder characteristics, there is a possibility that CA:Eu2+ phosphors can be applied for PDPs.

BaAl2S4:Eu thin-film EL device using a new blue emitting EL phosphor was prepared by the two targets pulse-electron-beam evaporation. The maximum luminance level was 65 cd/m2 under the 50 Hz pulse voltage. The EL spectrum had blue emission with a peak around 470 nm due to the transition for Eu2+ ion. The CIE color coordinates of BaAl2S4:Eu EL device were x = 0.12 and y = 0.10. The performance of blue-emitting BaAl2S4:Eu EL devices is shown to be sufficient for commercial color EL display in color purity and luminance level.

This paper presents the switching control and VLSI architecture for the AAL2 switch. The ATM network with the AAL2 switch can efficiently transmit low-bit-rate data, even if the network has many endpoints. The switch is capable of not only switching AAL2 cells but also converting the header of other types of ATMs. The AAL2 switch is integrated into a single chip. The proposed ATM network is constructed by AAL2 switches attached to the ATM switches.

A new asynchronous transfer mode adaptation layer (AAL), called AAL2, is being designed mainly for low-bit-rate voice traffic, and nodes that can assemble and disassemble AAL2 cells are being developed to make AAL2 usage efficient. This paper investigates the delay and performance of AAL2 nodes by an analytical method. Then, using the results, it analyzes a network using AAL2 nodes and shows the bandwidth reduction achieved by using AAL2 switching nodes as transit nodes.