A
radio link protocol for a
communications system ensures that delivery of
Internet protocol data packets occurs within a set
delay bound for the packets, in order to satisfy specified
quality of service levels. Data packets arriving at a
transmitter are subdivided into data blocks. As each block is transmitted, the
transmitter starts an associated
acknowledgement timer. The
timer is turned off, before it expires, if the
transmitter timely receives from a
receiver a message informing the transmitter that the associated block was successfully received. If such message is not received, the
timer expires and the transmitter sends an
acknowledgement request
signal to the
receiver and starts an associated
panic timer. The
panic timer is turned off, before it expires, if the transmitter subsequently timely receives a message that the associated block was successfully received. If such message not received, the
panic timer expires and the transmitter sends one of more copies of the corresponding block to the
receiver before occurrence of the
delay bound. If the transmitter receives a negative
acknowledgement message from the receiver, that a block is missing or corrupted, the transmitter retransmits a copy of the block to the receiver. To reduce messaging traffic, the transmitter cancels acknowledgement and panic timers based upon information contained in negative acknowledgement messages, and the receiver can periodically send acknowledgement messages to inform the transmitter of successfully received blocks.