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US 2001/0055356 A1Published application
Multicast radio communication system and apparatus
AssigneeKoninklijke Philips Electronics N.V.
InventorRobert J. Davies
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AssigneeKoninklijke Philips Electronics N.V.
InventorRobert J. Davies
Estimating the term…
A multicast radio data communication system comprising a master and a plurality of slave stations uses a retransmission protocol. Data (13) is transmitted by the master station and received by the slave stations. Slave stations having the weakest radio link are designated primary stations, and all other slaves are designated secondary stations. Any slave station may transmit a negative acknowledgement but only the primary stations may transmit a positive acknowledgement. Positive acknowledgements are transmitted in separate time slots (1,2,3,4), but negative acknowledgements (9,10) transmitted by the secondary stations overlap the positive acknowledgements transmitted by primary stations. These negative acknowledgements corrupt reception of the positive acknowledgement by the master station, thereby ensuring that the data is retransmitted.
A multicast radio system comprising a master station and a plurality of slave stations, the master station comprising means to transmit data to the plurality of slave stations simultaneously, each slave station comprising means to receive the data and means for determining whether it requires retransmission of the data, wherein at least one slave station is in a first state and the other slave station or slave stations is or are in a second state, wherein the or each slave station in the first state, if retransmission is not required, transmits a positive acknowledgement in a predetermined time slot which is substantially non-overlapping with any positive acknowledgement transmitted by any other slave station in the first state, wherein the or each slave station in the second state does not transmit an acknowledgement if retransmission is not required and transmits a negative acknowledgement if retransmission is required, wherein at least one negative acknowledgement transmitted by at least one slave station in the second state is transmitted at least partially concurrently with the or at least one said predetermined time slot, and wherein the master station retransmits the data if it does not receive the positive acknowledgement from the or each of the slave stations in the first state or if it receives at least one negative acknowledgement, and if the validity of the data has not expired.
A master radio station for use in a multicast radio network comprising a master station and a plurality of slave stations, the master station comprising means to command at least one of the slave stations of the plurality to adopt a first state wherein the slave station transmits a positive acknowledgement in response to receiving data that it does not need to have retransmitted, means to command at least one other of the slave stations of the plurality to adopt a second state wherein the slave station does not transmit an acknowledgement in response to receiving data that it does not need to have retransmitted and transmits a negative acknowledgement in response to receiving data which it needs to have retransmitted, means to instruct the or each slave station in the first state of a time slot in which to transmit the positive acknowledgement such that positive acknowledgements transmitted by more than one slave station are transmitted at substantially non-overlapping times, means to transmit data to the plurality of slave stations simultaneously, means to receive acknowledgements from the plurality of slave stations, and means to retransmit the data if the positive acknowledgement is not received from each of the slave stations in the first state or if at least one negative acknowledgement is received, and if the validity of the data has not expired.
A slave radio station for use in a multicast radio network comprising a master station and a plurality of slave stations, the slave station comprising means for setting the slave station into a first state and into a second state, means for receiving data from the master station, means for determining whether the slave station requires retransmission of the data, wherein in the first state, if it does not require retransmission of the data, the slave station transmits a positive acknowledgement in a predetermined time slot which is substantially non-overlapping with any positive acknowledgement transmitted by any other slave station in the first state, and wherein in the second state the slave station does not transmit a positive acknowledgement and transmits a negative acknowledgement if it requires retransmission of the data, the negative acknowledgement being transmitted at least partially concurrently with at least one time slot predetermined for the transmission of a positive acknowledgement.
Dependencies are inferred from the claim text.