Patent ID: 8176377

Claim:
A method for transmitting back to at least one first unit, short ACK/NACK bitmaps generated by a second unit in an ARQ signalling context inside a mobile radio system, where the short ACK/NACK bitmaps contain less bits than extended bitmaps and transmissions thereof are scheduled for a temporary block flow and avail of at least a carrier accessed in time division during timeslots of sequential frames for conveying RLC/MAC radio blocks each having a header and a payload data part distributed on a set of allocated timeslots interleaved between a predetermined number of frames, where each short ACK/NACK bitmap includes as many bits as a received number of RLC/MAC blocks received in a time window spanning at least one predetermined block period before a starting point of time known to the at least one first unit and the second unit, a logical value of each bit indicating correctly or erroneously decoded RLC/MAC blocks to enable retransmission by the at least one first unit of those blocks mapped as erroneously decoded by the second unit, comprising: encoding a short ACK/NACK bitmap by the second unit independently of a redundancy code of the payload data part, using a first modulation and coding scheme for the short ACK/NACK bitmap more robust against errors than a robustness of a second modulation and coding scheme used for the payload data part; and allocating the short ACK/NACK bitmap into a third part of the RLC/MAC block transmitted in the downlink by the second unit, configured as a base station, towards the at least one first unit, each configured as a mobile station, the third part being independently encoded with respect to both the header and the payload data part, and being accessed by all mobile stations on the allocated timeslots.