Koninklijke Philips Corporation N.V.

Engelbertus Van Willigen

Robert Schipper

In an interactive broadcast system signals transmitted by a service provider () are passed via a gateway () to a subscriber terminal (). In order to gain access to services, the subscriber terminal () transmits an authorization request message via the gateway () to the RADIUS server (). This RADIUS server () transmits in response to the authorization request message an authorization challenge message to the subscriber terminal (). In return the subscriber terminal responds to the challenge message with a challenge response. This challenge response is checked by the RADIUS server () and if correct, the RADIUS server () transmits a message to the gateway to give the subscriber terminal access to the service.

Broadcast network with interactive services

Described is a satellite communication system comprising a primary station , a communication satellite and at least one secondary station . The primary station transmits data signals via the communication satellite to the secondary station . The primary station comprises a modulator for modulating the data signals onto at least two differently FEC-encoded frequency carriers. The secondary station comprises a tuner for tuning to one of the frequency carriers in dependence on a tuning signal received from the primary station . The secondary station further comprising signal quality determining means for determining at least an estimate of a signal quality of the frequency carrier presently tuned to. The secondary station comprising retuning request transmit means for transmitting a retuning request signal to the primary station when the estimate of the signal quality becomes lower than a predetermined threshold value. The primary station comprises determining means for determining a frequency carrier with a better signal quality upon reception of the retuning request signal and tuning signal transmit means for transmitting the tuning signal indicating this frequency carrier to the secondary station . In this way, when the data signals (which are modulated onto a certain frequency carrier) are received poorly (e.g. because of rain fading) the secondary station can tune to a frequency carrier with a more robust FEC-encoding and the data signals can be received without problems.

Growing community of inventors

Hilversum, Netherlands

Engelbertus Van Willigen