Method for implementing a modified radio link protocol
View Patent ↗A method of performing a modified RLP that reduces the transmission delay in a communications system by detecting frame erasures when they occur. The modified RLP method requests retransmission of erased frames based on pattern violations instead of sequence number violations. The method is preconditioned to expect a particular repeating pattern of frame delivery. For a system running a VSELP vocoder, the method in a receiving device expects to receive full rate or data (F) and DTX (D) frames in a repeating pattern FFDFFDFFD. For a system running an AMBE vocoder, the method in a receiving device expects to receive frames in a repeating pattern DFDFDFDD. The method detects when the pattern is violated and in desired instances immediately requests retransmission of the expected frame.
1. A method for implementing a modified radio link protocol (RLP) in a mobile communications device, the method comprising the steps of:
receiving a plurality of frames;
maintaining a current frame pattern of expected frame types; and
determining that a received frame of the plurality of frames violates a predetermined pattern of frames expected to be received based on the current frame pattern.
2. The method of claim 1 further comprising the step of communicating to a sending device that the received frame violates the predetermined pattern.
3. The method of claim 2 wherein the step of communicating comprises the step of generating a Smart NAK comprising a value corresponding to an expected sequence number of the received frame.
4. The method of claim 1 wherein the step of determining comprises the steps of:
determining that the received frame of the plurality of frames is a DTX frame and a data frame was expected; and
marking a next DTX frame a predetermined number of frames ahead in the current frame pattern as a Retransmission frame.
5. The method of claim 1 wherein the step of determining comprises the steps of:
determining that the received frame of the plurality of frames is a Signaling frame and a data frame was expected; and
marking a next DTX frame in the current frame pattern as a data frame.
6. The method of claim 1 wherein the step of determining comprises the steps of:
determining that the received data frame of the plurality of data frames is a Signaling frame and a Retransmission frame was expected; and
marking a next DTX frame in the current frame pattern as a Retransmission frame.
7. The method of claim 1 wherein the step of determining comprises the steps of:
determining that the received data frame of the plurality of data frames is a Retransmission frame and a data frame was expected; and
marking a first Retransmission frame in the current frame pattern as a DTX and marking a next DTX frame in the current frame pattern as a data frame.
8. The method of claim 1 wherein the step of determining comprises the steps of:
determining that the received data frame of the plurality of data frames is a Retransmission frame and a DTX frame was expected; and
marking a next Retransmission frame in the current frame pattern as a DTX frame.
9. The method of claim 1 wherein the step of determining comprises the steps of:
determining that the received data frame of the plurality of data frames is a data frame and a DTX frame was expected; and
marking a next data frame in the current frame pattern as a DTX frame.
10. The method of claim 1 wherein the step of determining comprises the steps of:
determining that the received data frame of the plurality of data frames is a data frame and a Retransmission frame was expected; and
marking a next data frame in the current frame pattern as a Retransmission frame.
11. The method of claim 1 wherein the step of determining comprises the steps of:
determining that the received data frame of the plurality of data frames is a DTX frame and a Retransmission frame was expected; and
marking a next DTX frame in the current frame pattern as a Retransmission frame.
12. The method of claim 1 wherein the predetermined pattern of frames is sent to the mobile communications device before the plurality of frames is received.
13. The method of claim 1 wherein the predetermined pattern of frames is learned by the mobile communications device by observing a traffic stream.
14. A method for implementing a modified radio link protocol (RLP) in an infrastructure equipment, the method comprising the steps of:
receiving a plurality of frames;
maintaining a current frame pattern of expected frame types; and
determining that a received frame of the plurality of frames violates a predetermined pattern of frames expected to be received based on the current frame pattern.
15. The method of claim 14 further comprising the step of communicating that the received frame violates the predetermined pattern.
16. The method of claim 15 wherein the step of communicating comprises the step of generating a Smart NAK comprising a value corresponding to an expected sequence number of the received frame.
17. The method of claim 16 wherein the step of determining comprises the steps of:
determining that the received frame of the plurality of frames is a DTX frame and a data frame was expected; and
marking a different DTX frame a predetermined number of frames ahead in the current frame pattern as a Retransmission frame.