Method and apparatus for robust transmission of control information in wireless communication network

• US 8,005,039 B2
• Filed: 05/12/2009
• Issued: 08/23/2011
• Est. Priority Date: 12/30/2008
• Status: Active Grant

• Current Assignee: General Electric Company, Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Lincoln, Bo, Bergljung, Christian, Kamuf, Matthias
• Primary Examiner(s): Duong; Frank
• Application Number:
  US12/464,615
• Publication Number:
  US 20100165847A1
• Time in Patent Office: 833 Days
• Field of Search: 370203-208, 370324-339, 370/342, 370/349
• US Class Current: 370/328
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0058 Allocation criteria
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A base station includes transmitter and associated processing circuits. The transmitter circuits are configured to transmit control information and data traffic to mobile terminals in repeating transmission intervals, each interval having defined control and data portions. The processing circuits are configured to dynamically determine that the control portion has insufficient resources for transmitting control information to one or more of the mobile terminals, and, in response, at least temporarily transmit control information in the data portion, rather than in the control portion, for a selected one or more of the mobile terminals. Correspondingly, a mobile terminal is configured to selectively search for and decode control information in the data portion of one or more transmission intervals, rather than in the control portion.

Claims

1. A method in a wireless communication network base station of transmitting downlink control information to a plurality of mobile terminals, said method comprising:

transmitting control information and data traffic to the mobile terminals in repeating transmission intervals, each transmission interval having a control portion that is defined for transmitting control information to targeted ones of the mobile terminals and a data portion that is defined for transmitting data traffic to targeted ones of the mobile terminals;

dynamically determining that the control portion has insufficient resources for transmitting control information to one or more of the mobile terminals by determining that an overall information-carrying capacity of the control portion is insufficient, in consideration of collective amounts of control information to be sent in the control portion and corresponding coding gains needed for reliable reception of that control information; and

responsive to said determining, at least temporarily transmitting control information in the data portion, rather than in the control portion, for a selected one or more of the mobile terminals.

2. The method of claim 1, further comprising, responsive to said determination, selecting the selected one or more of the mobile terminals according to a function that minimizes transmission resources in the data portion that are given over to the transmission of control information.

4. The method of claim 1, wherein transmitting control information and data traffic to mobile terminals in repeating transmission intervals comprises transmitting an Orthogonal Frequency Division Multiplex (OFDM) signal including repeating sub-frames as said repeating transmission intervals, each sub-frame comprising a Physical Downlink Control Channel (PDCCH) as said control portion of the sub-frames, and a Physical Downlink Shared Channel (PDSCH) as said data portion of the sub-frames.

5. The method of claim 4, wherein at least temporarily transmitting control information in the data portion, rather than in the control portion, for a selected one or more of the mobile terminals comprises transmitting control information that is targeted to the selected one or more mobile terminals on the PDSCH, rather than on the PDCCH.

6. The method of claim 5, further comprising at least temporarily defining an Extended PDCCH (E-PDCCH) on the PDSCH, and wherein transmitting control information that is targeted to the selected one or more mobile terminals on the PDSCH comprises transmitting the control information that is targeted to the selected one or more mobile terminals on the E-PDCCH.

3. A method in a wireless communication network base station of transmitting downlink control information to a plurality of mobile terminals, said method comprising:

transmitting control information and data traffic to the mobile terminals in repeating transmission intervals, each transmission interval having a control portion that is defined for transmitting control information to targeted ones of the mobile terminals and a data portion that is defined for transmitting data traffic to targeted ones of the mobile terminals;

dynamically determining that the control portion has insufficient resources for transmitting control information to one or more of the mobile terminals by determining that radio reception conditions at a particular one or more of the mobile terminals are such that a maximum coding gain achievable for control information transmitted in the control portion is insufficient for reliable reception of control information at the particular one or more of the mobile terminals; and

responsive to said determining, at least temporarily transmitting control information in the data portion, rather than in the control portion, for a selected one or more of the mobile terminals.

7. The method of claim 3, wherein at least temporarily transmitting control information in the data portion, rather than in the control portion, comprises transmitting control information targeted to the particular one or more of the mobile terminals in the data portion using a coding gain that is higher than the maximum coding gain achievable in the control portion.

8. The method of claim 3, wherein at least temporarily transmitting control information in the data portion comprises, at least for so long as the maximum coding gain of the control portion is deemed insufficient, transmitting control information that is targeted to the given mobile terminal in the data portion, rather than in the control portion.

9. The method of claim 8, further comprising reverting back to transmitting control information that is targeted to the given mobile terminal in the control portion, responsive to determining that the maximum coding gain achievable in the control portion is sufficient for reliable reception of control information by the given mobile terminal.

10. A method in a wireless communication network base station of transmitting downlink control information and data traffic to a plurality of mobile terminals in repeating transmission intervals, each said transmission interval predefined to include a control portion designated for transmitting control information and a data portion designated for transmitting data traffic, said method comprising:

using said control portion in said repeating transmission intervals to transmit control information for mobile terminals in a first subset of said plurality of mobile terminals, while using said data portion in said repeating transmission intervals to transmit data traffic to the mobile terminals in said first subset;

using said data portion in said repeating transmission intervals to transmit both control information and data traffic for mobile terminals in a second subset of said plurality of mobile terminals;

dynamically determining subset membership for individual ones in said plurality of mobile terminals.

11. The method of claim 10, wherein said base station transmits an Orthogonal Frequency Division Multiplex (OFDM) signal that includes repeating sub-frames as said repeating transmission intervals, each sub-frame comprising a Physical Downlink Control Channel (PDCCH) as said control portion of the sub-frames, and a Physical Downlink Shared Channel (PDSCH) as said data portion of the sub-frames.

12. The method of claim 11, further comprising at least temporarily defining an Extended PDCCH (E-PDCCH) on the PDSCH, and wherein using the data portion of said repeating transmission intervals for transmitting control information for the mobile terminals in said second subset comprises transmitting that control information on the E-PDCCH.

13. A base station for use in a wireless communication network, said base station comprising:

transmitter circuits configured to transmit control information and data traffic to mobile terminals in repeating transmission intervals, each transmission interval having a control portion that is defined for transmitting control information to targeted ones of the mobile terminals and a data portion that is defined for transmitting data traffic to targeted ones of the mobile terminals;

one or more processing circuits that are operatively associated with the transmitter circuits and are configured to;

dynamically determine that the control portion has insufficient resources for transmitting control information to one or more of the mobile terminals by determining that an overall information-carrying capacity of the control portion is insufficient, in consideration of collective amounts of control information to be sent in the control portion and corresponding coding gains needed for reliable reception of that control information; and

responsive to said determination, at least temporarily transmit control information in the data portion, rather than in the control portion, for a selected one or more of the mobile terminals.

14. The base station of claim 13, wherein the base station is configured to, responsive to said determination, select the selected one or more of the mobile terminals according to a function that minimizes transmission resources in the data portion that are given over to the transmission of control information.

15. The base station of claim 13, wherein the base station is configured to transmit control information and data traffic to mobile terminals in repeating transmission intervals by transmitting an Orthogonal Frequency Division Multiplex (OFDM) signal including repeating sub-frames as said repeating transmission intervals, each sub-frame comprising a Physical Downlink Control Channel (PDCCH) as said control portion of the sub-frames, and a Physical Downlink Shared Channel (PDSCH) as said data portion of the sub-frames.

16. The base station of claim 15, wherein the base station is configured to at least temporarily transmit control information in the data portion, rather than in the control portion, for a selected one or more of the mobile terminals by transmitting control information that is targeted to the selected one or more mobile terminals on the PDSCH, rather than on the PDCCH.

17. The base station of claim 16, wherein the base station is configured to at least temporarily define an Extended PDCCH (E-PDCCH) on the PDSCH, and to transmit control information that is targeted to the selected one or more mobile terminals on the PDSCH by transmitting the control information that is targeted to the selected one or more mobile terminals on the E-PDCCH.

18. A base station for use in a wireless communication network, said base station comprising:

transmitter circuits configured to transmit control information and data traffic to mobile terminals in repeating transmission intervals, each transmission interval having a control portion that is defined for transmitting control information to targeted ones of the mobile terminals and a data portion that is defined for transmitting data traffic to targeted ones of the mobile terminals;

one or more processing circuits that are operatively associated with the transmitter circuits and are configured to;

dynamically determine that the control portion has insufficient resources for transmitting control information to one or more of the mobile terminals by determining that radio reception conditions at a particular one or more of the mobile terminals are such that a maximum coding gain achievable for control information transmitted in the control portion is insufficient for reliable reception of control information at the particular one or more of the mobile terminals; and

responsive to said determination, at least temporarily transmit control information in the data portion, rather than in the control portion, for a selected one or more of the mobile terminals.

19. The base station of claim 18, wherein the base station is configured to at least temporarily transmit control information in the data portion, rather than in the control portion, by transmitting control information targeted to the particular one or more of the mobile terminals in the data portion using a coding gain that is higher than the maximum coding gain achievable in the control portion.

20. The base station of claim 18, wherein the base station is configured to at least temporarily transmit control information in the data portion by, at least for so long as the maximum coding gain of the control portion is deemed insufficient, transmitting control information that is targeted to the given mobile terminal in the data portion, rather than in the control portion.

21. The base station of claim 20, wherein the base station is configured to revert back to transmitting control information that is targeted to the given mobile terminal in the control portion, responsive to determining that the maximum coding gain achievable in the control portion is sufficient for reliable reception of control information by the given mobile terminal.