Granted Patent B1

US 8,432,866 · App. 13/676,624 · Granted Apr 30, 2013

Abstract

Claims (85)

1. A method for use in obtaining channel quality indicator in a communication system, the method comprising:

receiving a first transmission;

acquiring a number indicative of a size of a subsequent second transmission, the size being associated with the number of resource units assigned for the second transmission;

estimating a signal to interference ratio based on the received first transmission;

determining transmission parameter information including at least, one of a transport block size indicating a number of bits per packet, a modulation scheme and a code rate based on the signal to interference ratio and the number; and

transmitting the determined transmission parameter information to a device transmitting the first and second transmissions,

wherein the determining comprises:

calculating a maximum transmission bit rate based on the signal to interference ratio and the received number;

calculating a maximum transport block size based on the maximum transmission bit rate and a predetermined packet duration.

2. The method according to claim 1 , wherein the determining further comprises:

choosing, from a plurality of predetermined transport block sizes, the transport block size which is next smaller than the calculated maximum transport block size;

selecting the modulation scheme from a plurality of predetermined modulation schemes based on the chosen transport block size; and

deriving the code rate based on the selected modulation scheme.

3. The method according to claim 2 , wherein;

the plurality of predetermined modulation schemes is sorted by a number of data bits per modulated symbol in ascending order,

a plurality of predetermined code rate limits is assigned to the plurality of predetermined modulation schemes, respectively, and

the determining further comprises executing in a loop:

selecting the modulation scheme from the plurality of predetermined modulation schemes beginning with the lowest predetermined modulation scheme in ascending order; and

deriving the code rate based on the chosen transport block sizes and the selected predetermined modulation scheme,

until the derived code rate does not exceed the predetermined code rate limit assigned to the selected predetermined modulation scheme.

4. The method according to claim 3 , further comprising:

estimating an error rate based on the received first transmission;

computing a signal to interference ratio offset based on the error rate, a predetermined error rate limit, a predetermined offset step value, a predetermined minimum threshold offset and a predetermined maximum threshold offset; and

modifying the estimated signal to interference ratio by adding the computed signal to interference ratio offset to the estimated signal to interference ratio.

5. The method according to claim 3 , further comprising:

obtaining a threshold signal to interference ratio based on the highest transport block size of the plurality of predetermined transport block sizes and the acquired number; and

precluding the highest transport block size from the choosing, if the estimated signal to interference ratio does not exceed the threshold signal to interference ratio by a predetermined exceedance value.

6. The method according to claim 5 , further comprising:

estimating an error rate based on the received first transmission;

computing a signal to interference ratio offset based on the error rate, a first predetermined error rate limit, a predetermined offset step value, a predetermined minimum threshold offset and a predetermined maximum threshold offset, if the calculated maximum transport block size is less than a second highest transport block size of the plurality of predetermined transport block sizes;

computing a signal to interference ratio offset based on the error rate, a second predetermined error rate limit smaller than the first predetermined error rate limit, a predetermined offset step value, a predetermined minimum threshold offset and a predetermined maximum threshold offset, if the calculated maximum transport block size is equal to or greater than the second highest transport block size of the plurality of predetermined transport block sizes;

modifying the estimated signal to interference ratio by adding the computed signal to interference ratio offset to the estimated signal to interference ratio;

re-calculating the maximum transmission bit rate based on the signal to interference, ratio and the received number; and

re-calculating the maximum transport block size based on the maximum transmission hit rate and the predetermined packet duration.

7. The method according to claim 1 , further comprising receiving a signaling including the number indicative of a size of a subsequent second transmission,

wherein the acquiring comprises deriving the number from the signaling.

8. The method according to claim 1 , further comprising transmitting the transmission parameter information as recommended transmission settings for the subsequent second transmission.

9. An apparatus for use in obtaining channel quality indicator in a cellular system, the apparatus comprising at least one processor, and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus at least to:

receive a first transmissions;

acquire a number indicative of a size of a subsequent second transmission, the size being associated with the number of resource units assigned for the second transmission;

estimate a signal to interference ratio based on the received first transmission;

determine transmission parameter information including at least one of a transport block size indicating a number of bits per packet, a modulation scheme arid a code rate based on the signal to interference ratio and the number; and

transmit the determined transmission parameter information to a device transmitting the first and second transmissions,

wherein the at least one memory and the computer program code is configured to, with the at least one processor, further cause the apparatus to:

calculate a maximum transmission bit rate based on the signal to interference ratio and the received number;

calculate a maximum transport block size based on the maximum transmission bit rate and a predetermined packet duration.

10. The apparatus according to claim 9 , the at least one memory and the computer program code being configured to, with the at least one processor, further cause the apparatus to:

choose, from a plurality of predetermined transport block sizes, the transport block size which is next smaller than the calculated maximum transport block size;

select the modulation scheme from a plurality of predetermined modulation schemes based on the chosen transport block size; and

derive the code rate based on the selected modulation scheme.

11. The apparatus according to claim 10 , wherein:

the plurality of predetermined modulation schemes is sorted by a number of data bits per modulated symbol in ascending order,

a plurality of predetermined code rate limits is assigned to the plurality of predetermined modulation schemes, respectively, and

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to execute in a loop:

select the modulation scheme from the plurality of predetermined modulation schemes beginning with the lowest predetermined modulation scheme in ascending order; and

derive the code rate based on the chosen transport block sizes and the selected predetermined modulation scheme,

until the derived code rate does not exceed the predetermined code rate limit assigned to the selected predetermined modulation scheme.

12. The apparatus according to claim 11 , the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to:

estimate an error rate based on the received first transmission;

compute a signal to interference ratio offset based on the error rate, a predetermined error rate limit, a predetermined offset step value, a predetermined minimum threshold offset and a predetermined maximum threshold offset; and

modify the estimated signal to interference ratio by adding the computed signal to interference ratio offset to the estimated signal to interference ratio.

13. The apparatus according to claim 12 , the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to:

obtain a threshold signal to interference ratio based on the highest transport block size of the plurality of predetermined transport block sizes and the acquired number; and

preclude the highest transport block size from the choosing, if the estimated signal to interference ratio does not exceed the threshold signal to interference ratio by a predetermined exceedance value.

14. The apparatus according to claim 13 , the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to:

estimate an error rate based on the received first transmission;

compute a signal to interference ratio offset based on the error rate, a first predetermined error rate limit, a predetermined offset step value, a predetermined minimum threshold offset and a predetermined maximum threshold offset, if the calculated maximum transport block size is less than a second highest transport block size of the plurality of predetermined transport block sizes;

compute a signal to interference ratio offset based on the error rate, a second predetermined error rate limit smaller than the first predetermined error rate limit, a predetermined offset step value, a predetermined minimum threshold offset and a predetermined maximum threshold offset, if the calculated maximum transport block size is equal to or greater than the second highest transport block size of the plurality of predetermined transport block sizes;

modify the estimated signal to interference ratio by adding the computed signal to interference ratio offset to the estimated signal to interference ratio;

re-calculate the maximum transmission bit rate based on the signal to interference ratio and the received number; and

re-calculate the maximum transport block size based on the maximum transmission bit rate and the predetermined packet duration.

15. The apparatus according to claim 9 , the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to

receive a signaling including the number indicative of a size of a subsequent second transmission; and

derive the number from the signaling.

16. The apparatus according to claim 9 , the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to transmit the transmission parameter information as recommended transmission settings for the subsequent second transmission.

17. The apparatus according to claim 9 , wherein the apparatus is operable as or at a base station or access node of a cellular system or as or at a terminal, user equipment, mobile station or modem in a cellular system, and/or

the apparatus is operable in at least one of a 3G, LTE and a LTE-A cellular system.

18. A computer program product comprising a non-transitory computer-readable storage medium baying computer readable instructions stored thereon, the computer readable instructions being executable by a computerized device to cause the computerized device to:

receive a first transmission; acquire a number indicative of a size of a subsequent second transmission, the size being associated with the number of resource units assigned for the second transmission;

estimate a signal to interference ratio based on the received first transmission;

determine transmission parameter information including at least one of a transport block size indicating a number of bits per packet, a modulation scheme and a code rate based on the signal to interference ratio and the number; and

transmit the determined transmission parameter information to a device transmitting the first and second transmissions,

wherein the computerized device is further caused to:

calculating a maximum transmission bit rate based on the signal to interference ratio and the received number;

calculating a maximum transport block size based on the maximum transmission bit rate and a predetermined packet duration.

Assignments (8)