Uplink coverage via autonomous retransmission

1. A device comprising:

a memory to store a plurality of instructions; and

a processing unit configured to execute instructions in the memory to:

determine whether power is limited in the device,

determine whether the device is using a minimum usable enhanced dedicated channel, E-DCH, transport format combination, ETFC,

receive consecutive negative acknowledgments, NACKs,

determine whether the number of consecutive NACKs is greater than a predefined number,

measure a downlink channel quality,

determine whether the measured downlink channel quality is less than a predefined threshold,

trigger autonomous retransmission, where a number of retransmissions are sent consecutively without waiting for receipt of a negative acknowledgement before starting the next retransmission, when power is limited in the device, when the device is using the minimum usable ETFC, and when one of:

the number of consecutive NACKs is greater than the predefined number, and

the measured downlink channel quality is less than the predefined threshold,

determine whether a difference between an estimated data signal-to-interference ratio, SIR, associated with a channel and a SIR for a transport format is greater than a certain decibel level, and

trigger autonomous retransmission when power is limited in the device, when the device is using the minimum usable ETFC, and when the difference is greater than the certain decibel level.

2. The device of claim 1 , wherein the device comprises user equipment (UE).

3. The device of claim 1 , wherein the processing unit further is configured to execute instructions in the memory to determine a number of retransmissions for the autonomous retransmission.

4. The device of claim 3 , wherein, when determining a number of retransmissions, the processing unit further is configured to execute instructions in the memory to:

obtain a required power offset for a transport format, P OFFREQ ,

obtain an actually used power offset for the transport format, P OFFUSED , and

calculate the number of retransmissions based on P OFFREQ , and P OFFUSED .

5. The device of claim 3 , wherein the processing unit further is configured to execute instructions in the memory to:

receive negative acknowledgments, NACKs, and positive acknowledgements, ACKs,

increase the number of retransmissions when a certain number of consecutive NACKs are received, and

decrease the number of retransmissions when a certain number of consecutive ACKs are received.

6. The device of claim 3 , wherein the processing unit further is configured to execute instructions in the memory to:

estimate a received signal-to-interference ratio, SIR EST , associated with another device, and compare a SIR required for a transport format, SIR REQ , and the SIR EST to calculate retransmission times for the autonomous retransmission.

7. The device of claim 6 , wherein, when estimating a received signal-to-interference ratio, SIR EST , the processing unit further is configured to execute instructions in the memory to:

measure a path gain to the other device via a transmission power, P TX , of a common pilot channel, CPICH, and a received signal code power, RSCP, of the CPICH,

estimate an interference, I, at the other device, when ACKs are received, based on the path gain, the P TX , and the SIR REQ ,

measure a new path gain,

determine the SIR EST based on the interference, the new path gain, and

the P TX , and calculate the retransmission times based on the SIR REQ and the determined SIR EST .

8. The device of claim 1 , wherein the processing unit is further configured to execute instructions in the memory to:

generate a notification, using a very large E-DCH transport format combination indicator, E-TFCI, the notification indicating that the device is using a small E-DCH transport format indicator, ETFI, and several autonomous retransmissions, and

provide the notification to another device.

9. A method, performed by user equipment associated with a wireless environment, the method comprising the steps of:

receiving consecutive negative acknowledgments, NACKs,

measuring a downlink channel quality associated with the user equipment,

triggering autonomous retransmission, where a number of retransmissions are sent consecutively without waiting for receipt of a negative acknowledgement before starting the next retransmission, when power is limited in the user equipment, when the user equipment is using a minimum usable enhanced dedicated channel, E-DCH, transport format combination, ETFC, and when one of:

a number of consecutive NACKs is greater than a predefined number, or

the measured downlink channel quality is less than a predefined threshold;

determining whether a difference between an estimated data signal-to-interference ratio, SIR, associated with a channel and a SIR for a transport format is greater than a certain decibel level, and

triggering autonomous retransmission when power is limited in the user equipment, when the user equipment is using the minimum usable ETFC, and when the difference is greater than the certain decibel level.

10. The method of claim 9 , further comprising the step of determining a number of retransmissions for the autonomous retransmission.

11. The method of claim 10 , further comprising the steps of:

receiving negative acknowledgments, NACKs, and positive acknowledgements, ACKs,

increasing the number of retransmissions when a certain number of consecutive NACKs are received, and

decreasing the number of retransmissions when a certain number of consecutive ACKs are received.

12. The method of claim 9 , further comprising the steps of:

generating a notification using a very large E-DCH transport format combination indicator, E-TFCI, the notification indicating that the user equipment is using a small E-DCH transport format indicator, ETFI, and several autonomous retransmissions, and

providing the notification to a base station.

13. The device of claim 1 , wherein the processing unit is further configured to execute instructions in the memory to:

receive a number of retransmissions for the autonomous retransmission calculated based on a signal-to-interference ratio required for a transport format, SIR REQ , and a signal-to-interference ratio, SIR MEAS , associated with another device.

14. The method of claim 9 , further comprising:

receiving a number of retransmissions for the autonomous retransmission calculated based on a signal-to-interference ratio required for a transport format, SIR REQ , and a signal-to-interference ratio, SIR MEAS , associated with another device.