Can High Speed Packet Data Channel Support VoIP ??

Can Distributed, Packet Switched Cellular Network Support VoIP ? To answer this question, we conduct detailed study on VoIP performance in high speed downlink packet data (HSDPA) channel that will be used in UMTS packet networks. HSDPA is designed to deliver high packet throughput by exploring multi-user diversity due to independent signal variations that users perceive. Such system throughput improvement comes with the penalty of large variations in packet delay. This leads to packet loss and jitter to VoIP service. We also extend the study to terminals with mobility under the above base station router based architecture. The delay variation due to multi-user scheduling and base station roaming calls for vertical coupling among protocol layers with judiciously chosen parameters. Aggregation a proper number of VoIP packets into a transmission frame is necessary to exploit high burst throughput of HSDPA while balancing buffering delay. Performance is limited primarily by terminals located at cell boundaries which calls for diversity techniques coupled with admission control mechanism. This work also provides insights for distributed architecture design and deployment. To our knowledge, this work on VoIP was among the first in technical community and was released as a company whitepaper to customers of Lucent Technology.

Providing VoIP Service in UMTS-HSDPA with Frame Aggregation
Haitao Zheng, Gee Rittenhouse
IEEE ICASSP 2005, PA, March 2005
[Abstract, PDF ]

The Performance of Voice over IP over UMTS Downlink Shared Packet Channel under Different Delay Budgets
Haitao Zheng, Gee Rittenhouse and Mike Recchione
IEEE Vehicle Technology Conference (VTC fall), Orlando, FL, Oct. 2003
[Abstract, PDF]

Slides: ICASSP 2005
Haitao Zheng, April 16,2005