Configuration of downlink transmissions
There is presented a method for providing configuration for downlink transmission to a wireless device. The method is performed by a network node and comprises transmitting a Downlink Control Information (DCI) message comprising configuration for downlink transmission in a short Transmission Time Interval (sTTI). Network nodes, wireless terminals, computer programs, and computer program products thereof are also presented.
1. A method for providing configuration for downlink transmission to a wireless device, the method being performed by a network node, the method comprising:
transmitting a Downlink Control Information, DCI, message comprising configuration for downlink transmission in a short Transmission Time Interval, sTTI, which is shorter than a legacy Transmission Time Interval, TTI, wherein:
the sTTI data transmissions following a starting symbol index of 1 or 3 have a first pattern consisting of symbol lengths 3, 2, 2, 2, 2 and 3 in consecutive order, and
the sTTI data transmissions following a starting symbol index of 2 have a second pattern consisting of symbol lengths 2, 3, 2, 2, 2 and 3 in consecutive order.
2. The method according to claim 1 , wherein the DCI message is transmitted in a TTI frequency band for sTTI.
3. The method according to claim 1 , wherein the configuration comprises position of reference symbols and data symbols.
4. The method according to claim 3 , wherein the reference symbols are Downlink, DL, Demodulation Reference Signals, DMRS.
5. The method according to claim 1 , wherein the configuration comprises lengths of sTTIs.
6. The method according to claim 1 , wherein the sTTIs have a fixed length for each subframe.
7. The method according to claim 6 , wherein the sTTI length is two or seven symbols.
8. The method according to claim 1 , further comprising:
transmitting a data transmission to the wireless device on a short Physical Downlink Shared Channel, sPDSCH, according to the configuration of the DCI message.
9. The method according to claim 1 , wherein the DCI message is a slow DCI message and the slow DCI is sent on subframe basis.
10. The method according to claim 9 , wherein the slow DCI message is sent to a group of wireless devices.
11. The method according to claim 1 , wherein the DCI message is a fast DCI message, and the fast DCI message is sent to a specific wireless device and on symbol or sTTI basis.
12. The method according to claim 1 , wherein the sTTIs have a fixed pattern.
13. The method according to claim 1 , wherein the sTTIs have fixed starting symbols for DL sTTI data transmission within a subframe.
14. The method according to claim 13 , wherein the fixed starting symbol of an sTTI is the first symbol within a subframe in which that DL sTTI's data transmission can be performed.
15. The method according to claim 13 , wherein the fixed starting symbols is selected in dependence on a control region of the DL subframe.
16. The method according to claim 15 , wherein the fixed starting symbol is signaled by Physical Control Format Indicator Channel, PCFICH, or by Radio Resource Control, RRC.
17. The method according to claim 1 , further comprising:
determining a sTTI pattern to be used.
18. The method according to claim 17 , wherein the determining is based on latency requirements.
19. The method according to claim 1 , wherein the sTTIs have a first fixed pattern and a second fixed pattern.
20. The method according to claim 1 , wherein the sTTI patterns consist of symbol lengths 3, 2, 2, 2, 2 and 3 in consecutive order, or consist of symbol lengths 2, 3, 2, 2, 2 and 3 in consecutive order.
21. The method according to claim 1 , wherein the sTTI data transmissions following a starting symbol index of 1 or 3 have a first pattern and the sTTI data transmissions following a starting symbol index of 2 have a second pattern.
22. The method according to claim 1 , further comprising:
switching between different patterns between subframes.
23. A method for configuration of downlink transmission from a network node, the method being performed by a wireless device, the method comprising:
receiving a Downlink Control Information, DCI, message comprising configuration for downlink transmission in a short Transmission Time Interval, sTTI, which is shorter than a legacy Transmission Time Interval, TTI; and
determining an sTTI pattern to be used based on a starting symbol index within a subframe for the downlink transmission, wherein:
the sTTI data transmissions following a starting symbol index of 1 or 3 have a first pattern consisting of symbol lengths 3, 2, 2, 2, 2 and 3 in consecutive order, and
the sTTI data transmissions following a starting symbol index of 2 have a second pattern consisting of symbol lengths 2, 3, 2, 2, 2 and 3 in consecutive order.
24. The method according to claim 23 , wherein the DCI message is received in a TTI frequency band for sTTI.
25. The method according to claim 24 , wherein the sTTIs have fixed starting symbols within a DL subframe for data transmission.
26. The method according to claim 25 , wherein the fixed starting symbol of an sTTI is the first symbol within a subframe in which that DL sTTI's data transmission can be performed.
27. The method according to claim 25 , wherein the fixed starting symbols is selected in dependence on a control region of the DL subframe.
28. The method according to claim 27 , wherein the fixed starting symbol is signaled by Physical Control Format Indicator Channel, PCFICH, or by Radio Resource Control, RRC.
29. The method according to claim 23 , wherein the configuration comprises position of reference symbols and data symbols.
30. The method according to claim 29 , wherein the reference symbols are Downlink, DL, Demodulation Reference Signals, DMRS.
31. The method according to claim 23 , wherein the configuration comprises lengths of sTTIs.
32. The method according to claim 23 , wherein the sTTIs have a fixed length for each subframe.
33. The method according to claim 32 , wherein the sTTI length is two or seven symbols.
34. The method according to claim 23 , further comprising:
receiving a data transmission from the network node on a short Physical Downlink Shared Channel, sPDSCH, according to the configuration of the DCI message.
35. The method according to claim 23 , wherein the DCI message is a slow DCI message and the slow DCI is sent on subframe basis.
36. The method according to claim 23 , wherein the DCI message is a fast DCI message and the fast DCI message is sent to a specific wireless device and on symbol or sTTI basis.
37. The method according to claim 23 , wherein the sTTIs have a fixed pattern for each subframe.
38. The method according to claim 23 , wherein the determining is based on starting symbol index within a DL subframe for data transmission.
39. The method according to claim 23 , wherein the sTTIs have a first fixed pattern and a second fixed pattern.
40. The method according to claim 23 , wherein the sTTI patterns consist of symbol lengths 3, 2, 2, 2, 2 and 3 in consecutive order, or consist of symbol lengths 2, 3, 2, 2, 2 and 3 in consecutive order.
41. The method according to claim 23 , wherein the sTTI data transmissions following a starting symbol index of 1 or 3 have a first pattern and the sTTI data transmissions following a starting symbol index of 2 have a second pattern.
42. The method according to claim 23 , further comprising:
switching between different patterns between subframes.
43. A network node for providing configuration for downlink transmission to a wireless device, the network node comprising:
a processor; and
a computer program product storing instructions that, when executed by the processor, causes the network node to:
transmit a Downlink Control Information, DCI, message comprising configuration for downlink transmission in a short Transmission Time Interval, sTTI, which is shorter than a legacy Transmission Time Interval, TTI, wherein:
the sTTI data transmissions following a starting symbol index of 1 or 3 have a first pattern consisting of symbol lengths 3, 2, 2, 2, 2 and 3 in consecutive order, and
the sTTI data transmissions following a starting symbol index of 2 have a second pattern consisting of symbol lengths 2, 3, 2, 2, 2 and 3 in consecutive order.
44. A wireless device for configuration of downlink transmission from a network node, the wireless device comprising:
a processor; and
a computer program product storing instructions that, when executed by the processor, causes the wireless device to:
receive a Downlink Control Information, DCI, message comprising configuration for downlink transmission in a short Transmission Time Interval, sTTI, which is shorter than a legacy Transmission Time Interval, TTI; and
determine an sTTI pattern to be used based on a starting symbol index within a subframe for the downlink transmission, wherein:
the sTTI data transmissions following a starting symbol index of 1 or 3 have a first pattern consisting of symbol lengths 3, 2, 2, 2, 2 and 3 in consecutive order, and
the sTTI data transmissions following a starting symbol index of 2 have a second pattern consisting of symbol lengths 2, 3, 2, 2, 2 and 3 in consecutive order.
45. A non-transitory computer readable storage medium having stored thereon executable instructions that, when run on a network node, causes the network node to:
transmit a Downlink Control Information, DCI, message comprising configuration for downlink transmission in a short Transmission Time Interval, sTTI, which is shorter than a legacy Transmission Time Interval, TTI, wherein:
the sTTI data transmissions following a starting symbol index of 1 or 3 have a first pattern consisting of symbol lengths 3, 2, 2, 2, 2 and 3 in consecutive order, and
the sTTI data transmissions following a starting symbol index of 2 have a second pattern consisting of symbol lengths 2, 3, 2, 2, 2 and 3 in consecutive order.
46. A non-transitory computer readable storage medium having stored thereon executable instructions that, when run on a wireless terminal, causes the wireless terminal to:
receive a Downlink Control Information, DCI, message comprising configuration for downlink transmission in a short Transmission Time Interval, sTTI, which is shorter than a legacy Transmission Time Interval, TTI; and
determine an sTTI pattern to be used based on a starting symbol index within a subframe for the downlink transmission, wherein:
the sTTI data transmissions following a starting symbol index of 1 or 3 have a first pattern consisting of symbol lengths 3, 2, 2, 2, 2 and 3 in consecutive order, and
the sTTI data transmissions following a starting symbol index of 2 have a second pattern consisting of symbol lengths 2, 3, 2, 2, 2 and 3 in consecutive order.