US 7,733,893 B2 · Method and receiver for determining a jitter buffer level

Abstract

The invention relates to a method and a receiver having control logic means for determining a target packet level of a jitter buffer adapted to receive packets with digitized signal samples, which packets are subject to delay jitter, from a packet data network. According to the invention, the jitter buffer is made adaptive to current network conditions, i.e., the nature and magnitude of the jitter observed by the receiver, by collecting statistical measures that describe these conditions. The target buffer level is determined with regard to the effect of packet losses in terms of duration of the discontinued playback of the true signal. This effect is derived from statistical measures of the network conditions as perceived by the receiving side and as reflected by a probability mass function which is continuously updated with packet inter-arrival times. The target buffer level is the result of minimization of a cost function which weights the internal buffer delay and an expected length of buffer underflow.

Claims25

Dependent claims

A method of determining a target buffer level in a jitter-buffer in response to current network conditions of a packet data network, the jitter-buffer receiving data packets with digitized signal samples from the packet data network, the method including performing, at regular intervals, the steps of:

logging, for a most recent received packet, a packet inter-arrival time defined as a time elapsed since a previous packet was received;
updating, in response to the logging step, a probability mass function reflecting packet inter-arrival times;
using the updated probability mass function by a receiver having a control logic means to define an expected duration of an empty jitter buffer for an arbitrary buffer level;
providing a cost function as a function of the expected duration of an empty buffer at the arbitrary buffer level and a jitter buffer delay at the same arbitrary buffer level, wherein a weighting factor is applied to the jitter buffer delay;
and
determining the target buffer level as the jitter buffer level which minimizes the cost function.

3 more elements

A receiver for receiving data packets with digitized signal samples from a packet data network, the receiver including:

a jitter-buffer for storing the received data packets, wherein a buffer level indicates the amount of stored data packets;
and
control logic means for, at regular intervals, determining a target buffer level in the jitter-buffer in response to current network conditions of the packet data network, the control logic means further:
logging, for a most recent received packet, a packet inter-arrival time defined as a time elapsed since a previous packet was received;
updating, in response to the logging step, a probability mass function reflecting packet inter-arrival times;
using the updated probability mass function to define an expected duration of an empty jitter buffer for an arbitrary buffer level;
providing a cost function as a function of the expected duration of an empty buffer at the arbitrary buffer level and a jitter buffer delay at the same arbitrary buffer level, wherein a weighting factor is applied to the jitter buffer delay;
and
determining the target buffer level as the jitter buffer level which minimizes the cost function.

6 more elements

Dependencies are inferred from the claim text.

Method and receiver for determining a jitter buffer level

Life of this patent

Method and receiver for determining a jitter buffer level

Life of this patent

Abstract

Claims25