Pi-Chun Chen

An Analysis of VoIP Service Using 1

While voice-over-Internet protocol (VoIP) on wireline network is maturing, VoIP on wireless mobile network is still in its infancy. This disparity is due to the fact that the wireline bandwidth is abundant and can be traded off for delay performance and overhead, whereas bandwidth in wireless mobile network is still a scarce resource. With the deployment of 1

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EV-DO Revision A System

EV-DO revision 0 (DOr0) worldwide, the spectrum efficiency has been significantly improved. However, DOr0 still lacks of features essential for VoIP. For this reason, 1

Forward link performance analysis of the CDMA2000 ∗ 3G1X data system

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Performance of 1x EV-DO Revision A systems with best effort data and voice over IP

EV-DO revision A (DOrA) has been standardized in the 3GPP2 with many improvements favorable for VoIP implementation. In this paper, we identify challenges and explore the feasibility of implementing VoIP using DOrA. We develop both analytical and simulation models to evaluate the VoIP capacity and delay performance over the air interface.

Quality of service support in 1x EV-DO Revision A systems

Performance analysis of data networks based on the code division multiple access (CDMA) air interface including the CDMA2000∗ 3G1X and the Universal Mobile Telecommunications System (UMTS) requires development of new methodologies distinct from those used to analyze voice networks. In this paper, we present a set of analytical and simulation techniques of different complexity that are used to investigate different aspects of data system performance on the forward link. We demonstrate how the static-snapshot simulation model is used to obtain statistically significant system-level results valid for multi-cell wide area network deployment. These simulations are complemented by the dynamic model, which takes into account details of data traffic arrival and resource management algorithms on the air interface. It also provides insight into each individual users experience under different network loads when running different data applications over the CDMA2000 air interface. Key results of simulation models are verified via theoretical analysis techniques that demonstrate the consistency of the results obtained via different methods.

Method and apparatus for scheduling users to allocate data transmissions in communications systems

In Revision A of the 1x EV-DO (1x evolution data optimized) standard, a number of enhancements and new capabilities have been introduced. The reverse link supports hybrid automatic repeat request (HARQ) operation and a peak data rate of 1.8 Mbps. The forward link supports short and multi-user packet formats for greater efficiency as well as a peak data rate of 3.1 Mbps. The medium access control (MAC) layer is enhanced to handle multiple application flows with differing latency and error rate requirements simultaneously by providing per-flow quality of service (QoS) guarantees. In this paper, we evaluate 1x EV-DO Revision A forward and reverse link throughput performance improvement for best effort data applications. Further, we study system performance when best effort data shares the bandwidth with delay sensitive QoS applications such as Voice over IP (VoIP) and investigate the implications of their interaction on capacity, voice quality, and aggregate system throughput.

Multiple carrier resource management

Quality of service (QoS) support in wireless data networks becomes ever more imperative in the face of rapid introduction of multimedia services into the wireless domain. In this paper, we discuss the limitations of supporting end-to-end QoS applications in the current 1x EV-DO Release 0 system. We give an overview of the newly developed CDMA2000∗ standards framework that allows flow-based QoS authorization, negotiation, admission, enforcement, and accounting for 1x EV-DO Revision A systems. We investigate key QoS techniques, with an emphasis on air interface scheduling, media access control, call/flow admission, overload control, and flow classification. A video telephony (VT) application is used to demonstrate the effectiveness of these techniques. Finally, we highlight several advancements of 1x EV-DO QoS development directions.