ENHANCED CARRIER AGGREGATION IN COMMUNICATIONS

• US 20180102892A1
• Filed: 04/10/2015
• Published: 04/12/2018
• Est. Priority Date: 04/10/2015
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Inventors: LUNTTILA, Timo Erkki, TIIROLA, Esa Tapani, HOOLI, Kari Juhani, HUGL, Klaus
• Granted Patent: US 10,530,553 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1822 involving configuration of automatic repeat request [ARQ] with parallel processes
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 1/1861 Physical mapping arrangements for ACK signaling see also H04L5/0053
• CPC Class Codes: H04L 2001/125 Arrangements for preventing errors in the return channel
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames

Abstract

A method comprises defining (401), in a network node (e NB), scheduled downlink carriers from a list of configured downlink carriers. The network node (e NB) defines (401) a downlink assignment index of the scheduled carrier having at least the lowest carrier index from the list of configured carriers, based on a total number of scheduled carriers. The network node (e NB) defines (401) the downlink assignment index for each other scheduled carrier having a higher carrier index from the list of configured carriers. The network node (e NB) transmits (402) to a terminal device (UE) a control message corresponding to each scheduled carrier, the control message indicating a downlink assignment scheduling a physical downlink shared channel, and comprising the defined downlink assignment index. The network node (e NB) receives (405) from the terminal device (UE), uplink control signalling indicating HARQ-ACKs related to physical downlink shared channels corresponding to the scheduled carriers.

Claims

1-24. -24. (canceled)

25. An apparatus comprising

at least one processor;

and

at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to define scheduled downlink carriers from a list of configured downlink carriers;

define a downlink assignment index of the scheduled carrier having at least the lowest carrier index from the list of configured downlink carriers, based on a total number of scheduled carriers;

define the downlink assignment index for each other scheduled carrier having a higher carrier index from the list of configured downlink carriers;

based on the defining, cause to a terminal device transmission of a control message corresponding to each scheduled carrier, the control message indicating a downlink assignment scheduling a physical downlink shared channel, and comprising at least one information element indicating the defined downlink assignment index;

receive, from the terminal device, uplink control signalling indicating HARQ-ACKs related to physical downlink shared channels corresponding to the scheduled carriers.

26. The apparatus of claim 25, wherein the downlink assignment index is defined for one or more of frequency division duplex and time division duplex, wherein in the case of frequency division duplex, the downlink assignment index of the scheduled carrier having at least the lowest carrier index from the list of configured downlink carriers in a sub-frame indicates the total number of scheduled carriers in the sub-frame.

27. The apparatus of claim 25, wherein the downlink assignment index is defined for one or more of frequency division duplex and time division duplex, wherein in the case of time division duplex, common downlink assignment index encoding is applied for each time division duplex sub-frame within the scheduling window, wherein the downlink assignment index is incremented in frequency first, time second manner over each scheduled carrier and sub-frame, and wherein

the downlink assignment index of the scheduled carrier with at least the lowest carrier index from the list of configured downlink carriers in a sub-frame indicates the number of scheduled carriers in said sub-frame;

the downlink assignment index of the scheduled carrier with at least the lowest carrier index from the list of configured downlink carriers in a sub-frame indicates the total number of scheduled carriers in said sub-frame and previous sub-frames of the scheduling window;

or

the downlink assignment index of the scheduled carrier with at least the lowest carrier index from the list of configured downlink carriers in a sub-frame indicates the total number of scheduled carriers in the selected sub-frame, except that in the last sub-frame of the scheduling window, the downlink assignment index indicates the total number of scheduled carriers in each sub-frame of the scheduling window.

28. The apparatus of claim 25, wherein it is defined that

DAI=(number of scheduled carriers-1) modulo (2^N)

wherein DAI is the downlink assignment index of the scheduled carrier having at least the lowest carrier index, and

N is the number of downlink assignment index bits;

or wherein it is defined that

DAI(m)=(m−

1) modulo (2^N)

wherein DAI(m) is the downlink assignment index of a scheduled carrier having a carrier index higher than the lowest carrier index,

m is the carrier index, and

N is the number of downlink assignment index bits.

29. The apparatus of claim 25, wherein the carrier index order is obtained based on a serving cell index configuration or other higher layer cell order configuration.

30. The apparatus of claim 25, wherein a HARQ-ACK codebook size is determined based on at least one of

an ACK/NACK resource index, and

the downlink assignment index of the scheduled carrier and the downlink assignment index of the scheduled carrier having at least the lowest carrier index from the list of configured downlink carriers and, the number of scheduled carriers.

31. The apparatus of claim 25, wherein the carrier indexes are obtained by ranking the scheduled carriers according to their respective serving cell index.

32. The apparatus of claim 25, wherein at least one of:

the downlink assignment index of the scheduled carrier group having at least the lowest carrier group index from a list of configured carrier groups is defined based on a total number of scheduled carrier groups; and

the downlink assignment index of scheduled carrier groups having a higher carrier group index from the list of configured carrier groups is defined based on a linear incrementing operation from one scheduled carrier group to the next in an increasing carrier group index order; and

the downlink assignment index of the scheduled carrier having a carrier index from the lowest carrier index to the L'"'"'th lowest carrier index, depends on a total number of scheduled carriers, wherein L is a predetermined ordinal number of the carrier index.

33. The apparatus of claim 25, wherein the at least one memory and the computer program code are further configured, with the at least one processor, to cause the apparatus to:

receive, in the network node from the terminal device, a HARQ-ACK feedback message assuming a predetermined number of HARQ-ACK bits for the sub-frame, if less than a predetermined threshold number of downlink assignments have been sent to the terminal device.

34. An apparatus comprising

at least one processor;

and

at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to receive, from a network node, a downlink assignment scheduling a physical downlink shared channel, and downlink assignment indexes of scheduled carriers;

responsive to the receiving, determine the number of scheduled carriers based on the downlink assignment indexes of the received downlink assignments;

determine a HARQ-ACK codebook size;

determine resources for conveying a HARQ-ACK message;

based on the determining, cause transmission of a control message to the network node, the control message comprising at least one information element indicating HARQ-ACKs related to physical downlink shared channels corresponding to the determined number of scheduled carriers.

35. The apparatus of claim 34, wherein the downlink assignment index is defined for one or more of frequency division duplex and time division duplex, wherein in the case of frequency division duplex, the downlink assignment index of the scheduled carrier having at least the lowest carrier index from the list of configured downlink carriers in a sub-frame indicates the total number of scheduled carriers in the sub-frame.

36. The apparatus of claim 34, wherein the downlink assignment index is defined for one or more of frequency division duplex and time division duplex, wherein in the case of time division duplex, common downlink assignment index encoding is applied for each time division duplex sub-frame within the scheduling window, wherein the downlink assignment index is incremented in frequency first, time second manner over each scheduled carrier and sub-frame, and wherein

the downlink assignment index of the scheduled carrier with at least the lowest carrier index from the list of configured downlink carriers in a sub-frame indicates the number of scheduled carriers in said sub-frame;

the downlink assignment index of the scheduled carrier with at least the lowest carrier index from the list of configured downlink carriers in a sub-frame indicates the total number of scheduled carriers in said sub-frame and previous sub-frames of the scheduling window;

or

the downlink assignment index of the scheduled carrier with at least the lowest carrier index from the list of configured downlink carriers in a sub-frame indicates the total number of scheduled carriers in the selected sub-frame, except that in the last sub-frame of the scheduling window, the downlink assignment index indicates the total number of scheduled carriers in each sub-frame of the scheduling window.

37. The apparatus of claim 34, wherein it is defined that

DAI=(number of scheduled carriers-1) modulo (2^N)

wherein DAI is the downlink assignment index of the scheduled carrier having at least the lowest carrier index, and

N is the number of downlink assignment index bits;

or wherein it is defined that

DAI(m)=(m−

1) modulo (2^N)

wherein DAI(m) is the downlink assignment index of a scheduled carrier having a carrier index higher than the lowest carrier index,

m is the carrier index, and

N is the number of downlink assignment index bits.

38. The apparatus of claim 34, wherein the carrier index order is obtained based on a serving cell index configuration or other higher layer cell order configuration.

39. The apparatus of claim 34, wherein a HARQ-ACK codebook size is determined based on at least one of

an ACK/NACK resource index, and

the downlink assignment index of the scheduled carrier and

the downlink assignment index of the scheduled carrier having at least the lowest carrier index from

the list of configured downlink carriers and,

the number of scheduled carriers.

40. The apparatus of claim 34, wherein the carrier indexes are obtained by ranking the scheduled carriers according to their respective serving cell index.

41. The apparatus of claim 34, wherein the number of scheduled carriers is determined based on the downlink assignment index of the scheduled carrier having at least the lowest carrier index from a list of configured downlink carriers.

42. The apparatus of claim 34, wherein at least one of:

the downlink assignment index of the scheduled carrier group having at least the lowest carrier group index from a list of configured carrier groups is defined based on a total number of scheduled carrier groups;

the downlink assignment index of scheduled carrier groups having a higher carrier group index from the list of configured carrier groups is defined based on a linear incrementing operation from one scheduled carrier group to the next in an increasing carrier group index order; and

the downlink assignment index of the scheduled carrier having a carrier index from the lowest carrier index to the L′

th lowest carrier index, depends on a total number of scheduled carriers, wherein L is a predetermined ordinal number of the carrier index.

43. The apparatus of claims 34, wherein

if less than a predetermined threshold number of downlink assignments are detected in the terminal device, it is assumed that none of downlink assignment indexes indicates the total number of scheduled carriers, and a predetermined number of HARQ-ACK bits are reported to the network node for the sub-frame;

and

if at least a predetermined threshold number of downlink assignments are detected in the terminal device, it is assumed that the downlink assignment index indicates the total number of scheduled carriers for the sub-frame, and the HARQ-ACK codebook size is adjusted accordingly.

44. A method comprising

receiving, in a terminal device from a network node, a downlink assignment scheduling a physical downlink shared channel, and downlink assignment indexes of scheduled carriers;

responsive to the receiving, determining, in the terminal device, the number of scheduled carriers based on the downlink assignment indexes of the received downlink assignments;

determining, in the terminal device, a HARQ-ACK codebook size;

determining, in the terminal device, resources for conveying a HARQ-ACK message;

based on the determining, causing, in the terminal device, transmission of a control message to the network node, the control message comprising at least one information element indicating HARQ-ACKs related to physical downlink shared channels corresponding to the determined number of scheduled carriers.