The transmission system according to the invention can be used for reliably multicasting
a group of data packets from a primary station (2) via a network (4),
such as the Internet, to a plurality of secondary stations (6). The primary
station (2) collects feedback information, which is related to a state of
reception (Li) of the group of data packets, from the secondary stations
(6). In order to prevent an implosion of feedback information messages from
congesting the network (4) the primary station (2) repeatedly transmits
feedback requests, which comprise a reply probability value (p) and the worst state
of reception (Lthresh) reported to the primary station (2) thus
far, to the secondary stations (6). The secondary stations (6) transmit
the feedback information to the primary station (2) in dependence on the
reply probability value (p) and only when the state of reception (Li)
is worse than the worst state of reception reported thus far (Lthresh).
The reply probability value (p) and the worst state of reception reported thus
far (Lthresh) are adapted by the primary station (2) in dependence
on the feedback information received so that a maximum number of feedback information
messages are collected from the secondary stations (6) without congesting
the network (4). If the state of reception (Li) comprises the
number of data packets erroneously received (Li) by the secondary stations
(6), the primary station (2) can transmit correction information
based on this number of erroneously received data packets (Li) and the
group of data packets transmitted to the secondary stations (6) so that
the secondary stations (6) can effectively correct the erroneously received
data packets with the correction information.
