Showing papers by "Wai-Choong Wong published in 2000"
20 Nov 2000
TL;DR: A multiple access scheme based on time division duplexing (TDD) for peer-to-peer speech communications in a short-range mobile ad hoc network of wireless nodes aims to improve the utilisation of radio channel by taking into account the on-off patterns of speech.
Abstract: We propose a multiple access scheme based on time division duplexing (TDD) for peer-to-peer speech communications in a short-range mobile ad hoc network of wireless nodes. This reservation-based packet-switched scheme aims to improve the utilisation of radio channel by taking into account the on-off patterns of speech. The TDD frame suggested for the channels is divided into a control sub-frame and an information sub-frame. The busy indication control packets used to indicate the slot reservation is aimed at disseminating the channel status to new nodes joining the network and to ensure a collision-free data channel.
8 citations
TL;DR: A CORBA-based Real Time Stream Service (RTSS) that allows real-time streams to be managed through the ‘CORBA channel’ but by-passing the heavy CORBA protocol stacks to achieve an integrated QOS framework that incorporates both host scheduling and end-to-end network-level QOS to better support the processing of distributed multimedia applications over ATM networks.
Abstract: Advance object oriented computing platform such as the Common Object Request Broker Architecture (CORBA) provides a conducive and standardized framework for the development of distributed applications. Most of the off-the-shelf CORBA are implemented over legacy network transports and distributed processing platforms such as TCP/IP and RPC. They are not suitable for real-time applications due to their high processing overheads, and lack of features and mechanisms in supporting quality of service both at the network level and at the end-host level. To overcome this limitation we have designed and implemented a CORBA-based Real Time Stream Service (RTSS) that allows real-time streams to be managed through the ‘CORBA channel’ but by-passing the heavy CORBA protocol stacks. RTSS aims to achieve an integrated QOS framework that incorporates both host scheduling and end-to-end network-level QOS to better support the processing of distributed multimedia applications over ATM networks. For host scheduling, a novel scheme of frequency-based scheduling mechanism has been proposed to cope with dynamic CPU load condition. The scheme has been implemented for a stand-alone host and will be extended to the networked environment. At the network-level QOS, RTSS provides object-oriented application programming interfaces (APIs) which guarantee end-to-end QOS when operating directly over ATM adaptation layers. The benefits of RTSS for the development of real-time multimedia distributed applications are demonstrated through a number of experiments.
24 Sep 2000
TL;DR: An adaptive transmission scheme where the source code rate, channel code rate and modulation schemes are changed in an optimal way in response to varying channel conditions is designed.
Abstract: We first propose a new interlayer synchronization scheme for data partitioned video streams. Unlike conventional schemes, synchronization information is represented as bit position differences between layers and placed in the first layer, which is transmitted via a better channel. Based on data partitioning we design an adaptive transmission scheme where the source code rate, channel code rate and modulation schemes are changed in an optimal way in response to varying channel conditions.