Adaptive rate control in a communications system

A receiver for receiving packet-switched encoded media that is transmitted by a sender in a session via a shared resource, the receiver comprising:

• a bit-rate range determining processor circuit configured to determine a bit-rate range valid for the session, the bit-rate range having an upper limit and a lower limit;
• a bit-rate request estimation processor circuit configured to estimate a bit-rate adaptation by comparing a currently received bit-rate to the bit-rate range and estimating the bit-rate adaptation based on the comparison to the bit-rate range so that the currently received bit-rate is reduced more when the currently received bit-rate is closer to the upper limit of the bit-rate range than when the currently received bit-rate is closer to the lower limit of the bit-rate range, or so that the currently received bit-rate is increased more when the currently received bit-rate is closer to the lower limit of the bit-rate range than when the currently received bit-rate is closer to the upper limit of the bit-rate range;
• and
• a rate request processor circuit configured to request the sender to adapt a currently transmitted bit-rate in the session.

A sender for transmitting packet-switched encoded media in a session via a shared resource to a receiver, the sender comprising:

• a bit-rate range determining processor circuit configured to determine a bit-rate range valid for the session, the bit-rate range having an upper limit and a lower limit;
• a rate request reception processor circuit configured to receive a request from the receiver to adapt a currently transmitted bit-rate in the session;
• and
• a rate adaptation control unit configured to, in response to the request from the receiver, control a rate adaptation of the currently transmitted bit-rate in the session so that the currently transmitted bit-rate is reduced more when the currently transmitted bit-rate is closer to the upper limit of the bit-rate range than when the currently transmitted bit-rate is closer to the lower limit of the bit-rate range, or so that the currently transmitted bit-rate is increased more when the currently transmitted bit-rate is closer to the lower limit of the bit-rate range than when the currently transmitted bit-rate is closer to the upper limit of the bit-rate range.

A packet-switched communications system for controlling bit-rates of at least a first and a second session, the system comprising at least a first sender operable to communicate with a first receiver via a shared resource in the first session and a second sender operable to communicate with a second receiver via the shared resource in the second session, the system further comprising:

• a first bit-rate range determining processor circuit configured to determine a first bit-rate range valid for the first session, the first bit-rate range having an upper limit and a lower limit;
• a second bit-rate range determining processor circuit configured to determine a second bit-rate range valid for the second session, the second bit-rate range having an upper limit and a lower limit;
• a first rate adaptation control unit configured to control rate adaptation of a first current bit-rate of the first session so that the first current bit-rate is reduced more when the first current bit-rate is closer to the upper limit of the first bit-rate range than when the first current bit-rate is closer to the lower limit of the first bit-rate range, or so that the first current bit-rate is increased more when the first current bit-rate is closer to the lower limit of the first bit-rate range than when the first current bit-rate is closer to the upper limit of the first bit-rate range;
• and
• a second rate adaptation control unit configured to control rate adaptation of a second current bit-rate of the second session so that the second current bit-rate is reduced more when the second current bit-rate is closer to the upper limit of the second bit-rate range than when the second current bit-rate is closer to the lower limit of the second bit-rate range, or so that the second current bit-rate is increased more when the second current bit-rate is closer to the lower limit of the second bit-rate range than when the second current bit-rate is closer to the upper limit of the second bit-rate range.