VoIP over a wired link

Acknowledgements

Outline

Packet Radio Access Network

The Backhaul Link

Packetized Voice in Cellular Telephony

Queueing Model

The Protocol Stack

Aggregated Voice Traffic

General arrival process for aggregated voice traffic with random offsets

Arrival Process of Aggregated Voice Traffic: Offset Groups

Voice Sources

Simulation Results
(157 users over a T1 at 1.536 MbpS)

Effect of Loading
number of sessions

Effect of Correlation
one-step correlation shown

Gaussian Traffic Model

Gaussian Traffic Model

Queue Length

Queue Length Approximation

Queue Length Approximation

Scaling Factor

The Variance of A(t)

The Variance of A(t)

The Large Deviations Approximation
(157 users over 1.536 Mbps)

Why the hockeystick?

Intuition

Validation

Heavy Traffic Analysis

Heavy Traffic Analysis

Heavy Traffic Analysis

Stationary Density

Waiting Time Approximation

Validation
(157 users over 1.536 Mbps)

Validation

Slide 35

Ongoing work

Slide 37

Packetized Voice in Cellular Telephony
(numerical example: EVRC)

Correlation Structure of Vocoder Output

Voice Arrival Process

Traffic Shaping