Retransmission scheme in a cellular communication system
View Patent ↗An apparatus 300 for a cellular communication system ( 100 ) comprises a buffer ( 303 ) which receives data for transmission over an air interface ( 115 ). The buffer ( 303 ) is coupled to a scheduler ( 305 ) which schedules the data and allocates the physical resource of the air interface ( 115 ). The transmissions are performed using a retransmission scheme such as a Hybrid-Automatic Repeat reQuest scheme. A load processor ( 309 ) determines a load characteristic associated with the scheduler ( 305 ) and a target controller ( 311 ) sets a target parameter for the retransmission scheme in response to the load characteristic. Specifically, a block error rate target may be set in response to a load level of a cell or plurality of cells. A transmission controller ( 307 ) sets a transmission parameter for a transmission in response to the target parameter and a transmitter ( 301 ) transmits the data using the transmission parameter. Accordingly, an operating point of the retransmission scheme may be dynamically adjusted thereby reducing overall latency.
1. An apparatus for a cellular communication system, the apparatus comprising:
a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage;
load means for determining a load characteristic associated with the scheduler;
means for setting a target parameter for the retransmission scheme in response to the load characteristic; and
means for setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
2. The apparatus according to claim 1 wherein the transmission parameter comprises a message transmit power.
3. The apparatus according to claim 1 wherein the transmission parameter comprises a transmit power reference indication.
4. The apparatus according to claim 1 wherein the target parameter comprises an error rate.
5. The apparatus according to claim 4 wherein the error rate is a Block Error Rate (BLER).
6. The apparatus according to claim 1 wherein the transmission parameter comprises a modulation parameter.
7. The apparatus according to claim 1 wherein the transmission parameter comprises an error coding parameter.
8. The apparatus according to claim 1 wherein the transmission parameter comprises a transmission parameter set restriction.
9. The apparatus according to claim 1 wherein the transmission parameter is a transmission parameter of an initial transmission of a message.
10. The apparatus according to claim 1 wherein the probability of a retransmission is dependent on the setting of the transmission parameter.
11. The apparatus according to claim 1 wherein the load means is operable to determine the load characteristic in response to an amount of pending transmit data.
12. The apparatus according to claim 11 wherein the pending transmit data is associated with a single cell.
13. The apparatus according to claim 12 wherein the pending transmit data is associated with a radio controller common for a plurality of cells.
14. The apparatus according to any one of the claims 11 , 12 , and 13 wherein the amount of pending data corresponds to a transmit data buffer loading.
15. The apparatus according to claim 1 wherein the load means is operable to determine the load characteristic in response to a number of attached remote units.
16. The apparatus according to claim 1 wherein the transmission parameter is biased towards an increasing number of retransmissions for an increasing load.
17. The apparatus according to claim 1 further comprising means for measuring a performance characteristic; and wherein the means for setting the target parameter is further operable to set the target parameter in response to the performance characteristic.
18. The apparatus according to claim 1 wherein the transmission is a downlink transmission.
19. The apparatus according to claim 1 wherein the transmission is an uplink transmission.
20. The apparatus according to claim 19 wherein the load means is operable to determine the load characteristic in response to a load indication received from a remote unit.
21. The apparatus according to claim 19 further comprising means for transmitting an indication of the target parameter from a base station to a remote unit.
22. The apparatus according to claim 19 further comprising means for transmitting an indication of the transmission parameter from a base station to a remote station.
23. The apparatus according to claim 1 wherein the means for setting the transmission parameter is comprised in a base station, and the means for setting the target parameter is comprised in a radio network controller which is operable to communicate an indication of the target parameter to the base station.
24. The apparatus according to claim 1 further comprising means for communicating the target parameter to a scheduling function associated with a different cell than a cell associated with the means for determining the target parameter.
25. The apparatus according to claim 1 further comprising means for communicating the load characteristic to a scheduling function associated with a different cell than the means for determining the load characteristic parameter.
26. The apparatus according to claim 1 wherein the retransmission scheme is a Hybrid-Automatic Repeat reQuest (H-ARQ) scheme.
27. The apparatus according to claim 1 wherein the cellular communication system complies with the Technical Specifications of the 3 rd Generation Partnership Project (3GPP).
28. The apparatus according to claim 1 , wherein the transmission parameter increases resource usage and decreases retransmission probability.
29. The apparatus according to claim 28 , wherein the target parameter was set in response to a low load characteristic.
30. The apparatus according to claim 1 , wherein the transmission parameter decreases resource usage and increases retransmission probability.
31. The apparatus according to claim 30 , wherein the target parameter was set in response to a high load characteristic.
32. A base station for a cellular communication system; the base station comprising:
a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage;
load means for determining a load characteristic associated with the scheduler;
means for setting a target parameter for the retransmission scheme in response to the load characteristic; and
means for setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
33. A method of operation in a cellular communication system including at least a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage, the method comprising:
determining a load characteristic associated with the scheduler;
setting a target parameter for the retransmission scheme in response to the load characteristic; and
setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
34. The method according to claim 33 wherein the transmission parameter comprises a message transmit power.
35. The method according to claim 33 wherein the transmission parameter comprises a transmit power reference indication.
36. The method according to claim 33 wherein the target parameter comprises an error rate.
37. The method according to claim 36 wherein the error rate is a Block Error Rate (BLER).
38. The method according to claim 33 wherein the transmission parameter comprises a modulation parameter.
39. The method according to claim 33 wherein the transmission parameter comprises an error coding parameter.
40. The method according to claim 33 wherein the transmission parameter comprises a transmission parameter set restriction.
41. The method according to claim 33 wherein the transmission parameter is a transmission parameter of an initial transmission of a message.
42. The method according to claim 41 wherein the probability of a retransmission is dependent on the setting of the transmission parameter.
43. The method according to claim 33 wherein the determining of the load characteristic comprises determining the load characteristic in response to an amount of pending transmit data.
44. The method according to claim 43 wherein the pending transmit data is associated with a single cell.
45. The method according to claim 44 wherein the pending transmit data is associated with a radio controller common for a plurality of cells.
46. The method claimed in any previous according to claim 43 wherein the amount of pending data corresponds to a transmit data buffer loading.
47. The method according to claim 33 wherein the determining of the load characteristic comprises determining the load characteristic in response to a number of attached remote units.
48. The method according to claim 33 wherein the transmission parameter is biased towards an increasing number of retransmissions for an increasing load.
49. The method according to claim 33 further comprising measuring a performance characteristic; and wherein the setting of the target parameter comprises setting the target parameter in response to the performance characteristic.
50. The method according to claim 33 wherein the transmission is a downlink transmission.
51. The method according to claim 33 wherein the transmission is an uplink transmission.
52. The method according to claim 51 wherein the determining of the load characteristic comprises determining the load characteristic in response to a load indication received from a remote unit.
53. The method according to claim 51 further comprising transmitting an indication of the target parameter from a base station to a remote unit.
54. The method according to claim 51 further comprising transmitting an indication of the transmission parameter from a base station to a remote station.
55. The method according to claim 33 wherein the setting of the transmission parameter is performed by a base station, and the setting of the target parameter is performed by a radio network controller which further communicates an indication of the target parameter to the base station.
56. The method according to claim 33 further comprising communicating the target parameter to a scheduling function associated with a different cell than a cell associated with the determining of the target parameter.
57. The method according to claim 33 further comprising communicating the load characteristic to a scheduling function associated with a different cell than the determining of the load characteristic parameter.
58. The method according to claim 33 wherein the retransmission scheme is a Hybrid-Automatic Repeat reQuest (H-ARQ) scheme.
59. The method according to claim 33 wherein the cellular communication system complies with the Technical Specifications of the 3 rd Generation Partnership Project (3GPP).
60. A computer-readable medium storing executable instructions for operation in a cellular communication system including at least a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage, comprising instructions for:
determining a load characteristic associated with the scheduler;
setting a target parameter for the retransmission scheme in response to the load characteristic; and
setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
61. A record carrier comprising a computer program according to claim 60 .
62. An apparatus for a cellular communication system, the apparatus comprising:
a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage;
load means for receiving a load characteristic associated with the scheduler;
means for setting a target parameter for the retransmission scheme in response to the load characteristic; and
means for setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
63. An apparatus for a cellular communication system, the apparatus comprising:
a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage;
means for receiving a target parameter for the retransmission scheme, the target parameter being dependent on a load characteristic associated with the scheduler; and
means for setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
64. An apparatus for a cellular communication system including a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage, the apparatus comprising:
load means for receiving a load characteristic associated with the scheduler;
means for setting a target parameter for the retransmission scheme in response to the load characteristic; and
means for setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
65. An apparatus for a cellular communication system including a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage, the apparatus comprising:
means for receiving a target parameter for the retransmission scheme, the target parameter being dependent on a load characteristic associated with the scheduler; and
means for setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
66. An apparatus for a cellular communication system including a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage, the apparatus comprising:
load means for receiving a load characteristic associated with the scheduler; and
means for setting a target parameter for the retransmission scheme in response to the load characteristic, the target parameter being indicative of a setting of a transmission parameter for a transmission for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
67. A method for a cellular communication system including a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage, the method comprising:
receiving a load characteristic associated with the scheduler;
setting a target parameter for the retransmission scheme in response to the load characteristic; and
setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
68. A method for a cellular communication system including a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage, the method comprising:
receiving a target parameter for the retransmission scheme, the target parameter being dependent on a load characteristic associated with the scheduler; and
setting a transmission parameter for a transmission in response to the target parameter for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.
69. A method for a cellular communication system including a scheduler for scheduling data for transmission over an air interface of the cellular communication system using a retransmission scheme for affecting at least a retransmission probability and a resource usage, the method comprising:
determining a load characteristic associated with the scheduler; and
setting a target parameter for the retransmission scheme in response to the load characteristic, the target parameter being indicative of a setting of a transmission parameter for a transmission for affecting at least the retransmission probability and the resource usage according to the load characteristic, wherein the resource usage is related to the retransmission probability.