Data transmission over a communications link with variable transmission rates

A method of retransmitting data at variable rates at a first communications protocol layer in predetermined time intervals, where each of the predetermined time intervals has the same duration, comprising:

• receiving a request for retransmission of a data message previously transmitted using a first transmission format specifying a first transmission rate;
• segmenting at a second communications protocol layer above the first communications protocol layer the data message to be retransmit into fixed size protocol data units (PDUs), each fixed size PDU having the same number of bits independent of whether the PDU has the first or a second transmission format;
• and
• transmitting the fixed size PDUs via the first communications protocol layer using a second transmission format specifying a second transmission rate different from the first transmission rate at which the data message was originally transmitted during one or more of the predetermined time intervals.

A communications device comprising:

• a buffer configured to store data for transmission over a communications link;
• data processing circuitry configured to detect a first transmission rate associated with data to be transmitted over the communications link, and provide data bits at the first transmission rate into fixed size data blocks, each fixed size data block having the same number of bits;
• and
• a transmitter configured to transmit over the communications link at the first transmission rate during one or more of the predetermined time intervals, each time interval having the same duration, a first number of the fixed size data blocks per time interval corresponding to the first transmission rate;
• wherein the data processing circuitry is configured to detect a change in transmission rate over the communications link from the first transmission rate to a second transmission rate, provide data bits at the second transmission rate into the fixed size data blocks, and transmit a second number of the fixed size data blocks per time interval corresponding to the second transmission rate during one or more of the predetermined time intervals.

A communications protocol for data communications over a communications link between a mobile station and a base station, comprising:

• a first communications protocol layer for transmitting data over the communications link at variable rates in predetermined time intervals, where each of the predetermined time intervals has the same duration, and
• a second communications protocol layer for:
• (a) receiving a request to retransmit a data message previously transmitted using a first transmission format specifying a first transmission rate, and
• (b) segmenting the data message into fixed size protocol data units (PDUs),
• each fixed size PDU having the same number of bits,
• wherein the fixed size PDUs may be transmit at a second transmission rate different from the first transmission rate at which the data message was originally transmit during one or more of the predetermined time intervals via the first communications protocol layer.