Frequency selective almost blank subframes

• US 10,638,498 B2
• Filed: 02/27/2015
• Issued: 04/28/2020
• Est. Priority Date: 02/27/2015
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Cui, Zhi, Lei, Hongyan
• Primary Examiner(s): Wyllie, Christopher T
• Application Number:
  US14/633,230
• Publication Number:
  US 20160255631A1
• Time in Patent Office: 1,887 Days
• Field of Search: None
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/569 of the traffic information
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

Frequency selective almost blank subframes (ABS) are scheduled in a heterogeneous network in which a protected portion of an available frequency band is allocated to protected subframes transmitted in by a small cell during a first time period and an unprotected portion of the frequency band is allocated to non-protected subframes transmitted during the first time period by the macro cell. The macro cell in the heterogeneous network utilizes the unprotected portion of the frequency band to transmit data to served user equipment (UEs) during ABS while the small cell uses the protected portion of the frequency band to transmit data to served UEs during ABS. That can improve service to low latency applications both for UEs served by the macro cell and for UEs being served by the small cell(s).

Claims

1. A method comprising:

scheduling in a heterogeneous network including a macro cell and at least one small cell within the macro cell, a first subframe pattern of a first radio frame in which a protected portion of a frequency band is allocated to one or more protected subframes of a radio frame for data transmission by a small cell access point and in which an unprotected portion of the frequency band is allocated to the one or more protected subframes of the radio frame for data transmission by a macro cell access point and both the protected portion of the frequency band and the unprotected portion of the frequency band are allocated to be used for data transmission by the macro cell access point during unprotected subframes;

wherein the scheduling includes,

allocating a first plurality of resource blocks to the one or more protected subframes, the first plurality of resource blocks being the protected portion of the frequency band; and

allocating a second plurality of resource blocks to the one more protected subframes, the second plurality of resource blocks being the unprotected portion of the frequency band;

adapting the scheduling of the one or more protected subframes in the frequency domain and the time domain to a second subframe pattern for transmission during a second radio frame subsequent to the first radio frame, the adapting responsive to resource usage, the resource usage including, at least in part, macro and metro cell performance metrics;

adapting the scheduling in the frequency domain by assigning a third plurality of resource blocks to the protected portion of the frequency band during protected subframes transmitted in the second radio frame and assigning a fourth plurality of resource blocks to the unprotected portion of the frequency band during the protected subframes transmitted in the second radio frame; and

adapting the scheduling in the time domain by changing a number of protected subframes within the second radio frame as compared to the first radio frame.

2. The method as recited in claim 1 further comprising the macro cell access point transmitting almost blank subframes in the protected portion of the frequency band during the one or more protected subframes.

3. The method as recited in claim 1, further comprising:

scheduling user equipment in the macro cell on the unprotected subframes;

scheduling user equipment in the small cell on any of the protected or unprotected subframes of the first radio frame; and

scheduling user equipment in a small cell range expansion area only on the protected subframes of the first radio frame using the protected portion of the frequency band.

4. The method as recited in claim 1, further comprising:

adapting allocation of the protected subframes and unprotected subframes according to one or more low latency service requirements of the at least one small cell such that a spacing of protected subframes within the radio frame decreases with an increase in the one or more low latency service requirements; and

wherein the one or more low latency service requirements include voice over long term evolution (VoLTE).

5. The method as recited in claim 1 further comprising first control logic associated with the macro cell causing information identifying the protected and unprotected portions of the frequency band to be supplied to the small cell access point using a plurality of bits, with each bit of the plurality of bits corresponding to a respective resource block, a first value for each of the bits identifying an associated resource block as a protected resource block and a second value for each of the bits identifying the associated resource block as an unprotected resource block.

6. The method as recited in claim 1 further comprising first control logic associated with the macro cell causing information to be supplied to the small cell access point identifying the protected and unprotected portions of the frequency band by identifying one of a plurality of profiles, each of the profiles associated with a predetermined allocation of resource blocks to the protected portion and the unprotected portion of the frequency band.

7. The method as recited in claim 1 further comprising control logic in the macro cell instructing user equipment in an edge of the macro cell to measure one or more parameters of received signals only for the unprotected portion of the frequency band.

8. The method as recited in claim 1 further comprising control logic in the small cell instructing user equipment in an edge of the small cell to measure one or more parameters of received signals only for the protected portion of the frequency band.

9. A heterogeneous network including a macro cell and a small cell, the heterogeneous network comprising:

control logic associated with the macro cell configured to dynamically schedule, responsive to first performance information, a subframe pattern in frequency and time in which a first portion of a frequency band is protected in one or more protected subframes of a first radio frame, the first portion being a first plurality of resource blocks, and a second portion of the frequency band is unprotected during the one or more protected subframes, the second portion being a second plurality of resource blocks, the second portion of the frequency band for transmission of data by a macro cell access point in the macro cell during the one or more protected subframes and the macro cell access point does not transmit data in the first portion of the frequency band during the one or more protected subframes,

wherein the control logic is responsive to second performance information of the macro cell and the small cell to adjust a number of protected subframes within a second radio frame from a first number of protected subframes in the first radio frame to a second number of protected subframes in the second radio frame and to adjust allocation of the first portion of the frequency band that is protected in protected subframes of the first radio frame to a third portion of the frequency band that is protected in protected subframes of the second radio frame, the third portion of the frequency band having a third plurality of resource blocks and to adjust allocation of the second portion of the frequency band that is unprotected in the protected subframes of the first radio frame to a fourth portion of the frequency band that is unprotected in the protected subframes of the second radio frame, the fourth portion of the frequency band having a fourth plurality of resource blocks; and

at least one transmitter of the macro cell access point responsive to scheduling of the first radio frame by the control logic to transmit data in the second portion of the frequency band and not the first portion during the one or more protected subframes and to transmit data in the first portion and the second portion of the frequency band during unprotected subframes of the first radio frame and the at least one transmitter is responsive to scheduling by the control logic of the second radio frame to transmit data in the fourth portion of the frequency band and not the third portion of the frequency band during the protected subframes of the second radio frame and to transmit data in the third and fourth portions of the frequency band during the unprotected subframes of the second radio frame.

10. The heterogeneous network as recited in claim 9 wherein the at least one transmitter transmits almost blank subframes in the first portion of the frequency band during the protected subframes of the first radio frame and in the third portion of the frequency band during protected subframes of the second radio frame.

11. The heterogeneous network as recited in claim 9, wherein the control logic associated with the macro cell schedules user equipment served by the macro cell on the unprotected subframes of the first radio frame and in the second portion of the frequency band during the protected subframes.

12. The heterogeneous network as recited in claim 11, further comprising second control logic associated with the small cell, the second control logic configured to be responsive to information received from the control logic associated with the macro cell to schedule user equipment in a small cell range expansion area only in the first portion of the frequency band on the protected subframes of the first radio frame and to schedule user equipment in an inner part of the small cell on any of the protected or unprotected subframes of the first radio frame.

13. The heterogeneous network as recited in claim 11, wherein the control logic associated with the macro cell is responsive to adapt allocation of the protected and unprotected subframes of the first radio frame according to low latency service requirements of the small cell.

14. The heterogeneous network as recited in claim 9 further comprising the control logic associated with the macro cell configured to instruct user equipment in an edge of the macro cell to measure one or more parameters of received signals only for the second portion of the frequency band that is unprotected during the first radio frame.

15. The heterogeneous network as recited in claim 9 comprising control logic in the small cell configured to instruct user equipment in an edge of the small cell to measure one or more parameters of received signals only for the first portion of the frequency band that is protected during the first radio frame and only for the third portion of the frequency band that is protected during the second radio frame.

20. The heterogeneous network as recited in claim 9 wherein the control logic associated with the macro cell is configured to generate four bits of information identifying one of a plurality of profiles according to a value of the four bits, respective ones of the profiles associated with a predetermined allocation of respective resource blocks to the first portion and the second portion of the frequency band and the control logic is configured to cause a selected one of the plurality of profiles to be communicated to small cell control logic.

16. A heterogeneous network comprising:

a macro cell having a first coverage area and having a macro cell access point;

at least one small cell having a second coverage area that overlaps with a portion of the first coverage area and having a small cell access point;

first control logic associated with the macro cell includes a time and frequency scheduling component configured to schedule protected subframes of a first radio frame in time and frequency by scheduling a first number of subframes of the first radio frame to be the protected subframes and a second number of subframes of the first radio frame to be unprotected subframes and to schedule a first portion of a frequency band used during the protected subframes as a protected portion and a second portion of the frequency band used during the protected subframes as an unprotected portion, the first control logic being further configured to cause subframe pattern information regarding allocation of the first and second portions of the frequency band and which subframes of the first radio frame are protected subframes to be communicated to second control logic associated with the small cell;

the macro cell access point including at least one transmitter responsive to the scheduling to transmit data only over the unprotected portion during the protected subframes and to transmit data over the protected and unprotected portions during the unprotected subframes; and

at least one transmitter in the small cell to transmit data to user equipment in a range extension area of the small cell during the protected subframes using the protected portion of the frequency band;

wherein the time and frequency scheduling component allocates a first plurality of resource blocks to the protected portion of the frequency band in the protected subframes of the first radio frame;

wherein the time and frequency scheduling component allocates a second plurality of resource blocks to the unprotected portion of the frequency band in the protected subframes of the first radio frame;

wherein, responsive to performance information, the time and frequency scheduling component dynamically schedules a third number of subframes of a second radio frame to be protected subframes of the second radio frame and a fourth number of subframes of the second radio frame to be unprotected subframes of the second radio frame; and

wherein, responsive to the performance information, the time and frequency scheduling component dynamically allocates a third portion of the frequency band to a protected portion of the frequency band during the protected subframes of the second radio frame and allocates a fourth portion of the frequency band to an unprotected portion of the frequency band during the protected subframes of the second radio frame;

wherein the third portion of the frequency band is a third plurality of resource blocks and the fourth portion of the frequency band is a fourth plurality of resource blocks.

17. The heterogeneous network as recited in claim 16 wherein the time and frequency scheduling component is responsive to the performance information to increase a number of the protected subframes in the second radio frame from the first number of protected subframes in the first radio frame to the third number of protected subframes the second radio frame and to decrease the first plurality of resource blocks in the protected subframes of the first radio frame to the third plurality of resource blocks in the protected subframes of the second radio frame and to increase the fourth plurality of resource blocks in the protected subframes of the second radio frame from the second plurality of resource blocks in the protected subframes of the first radio frame.

18. The heterogenous network as recited in claim 16,

wherein second control logic in the small cell instructs first user equipment in an edge of the small cell to measure one or more parameters of received signals only for the first portion of the frequency band during the protected subframes of the first and second radio frames;

and

wherein the first control logic in the macro cell instructs second user equipment in an edge of the macro cell to measure one or more parameters of received signals only for the second portion of the frequency band during the protected subframes of the first radio frame and the fourth portion of the frequency band during the protected subframes of the second radio frame.

19. The heterogenous network as recited in claim 16,

wherein the first control logic associated with the macro cell is configured to generate as the subframe pattern information a first bit field including plurality of bits identifying the protected and unprotected portions of the frequency band, with each bit of the plurality of bits corresponding to a respective resource block, a first value for each of the bits identifying an associated resource block as a protected resource block during the protected subframes and a second value for each of the bits identifying the associated resource block as an unprotected resource block during the protected subframes;

wherein the first control logic is configured to generate as part of the subframe pattern information a second bit field that specifies which of the subframes of the first radio frame are unprotected subframes and which are protected subframes; and

wherein the first control logic is configured to transmit the first and second bit fields to the small cell access point.