Almost blank subframe in carrier aggregation

• US 9,549,382 B2
• Filed: 03/17/2016
• Issued: 01/17/2017
• Est. Priority Date: 10/29/2011
• Status: Active Grant

• Current Assignee: Comcast Cable Communications LLC (Comcast Corporation)
• Original Assignee: Ofinno Technologies, LLC (Ofinno, LLC)
• Inventors: Dinan, Esmael Hejazi
• Primary Examiner(s): Zaidi, Iqbal
• Application Number:
  US15/072,418
• Publication Number:
  US 20160205640A1
• Time in Patent Office: 306 Days
• Field of Search: 370328-339, 370433-473, 375130-140
• US Class Current: 1/1
• CPC Class Codes: H04H 20/33 by plural channels
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/06 Hybrid resource partitioning, e.g. channel borrowing
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/60 using different transmission rates for TPC commands
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A base station transmits a message to a plurality of wireless devices in connected mode. The message comprises a subframe allocation bitmap indicating a plurality of subframes. The plurality of subframes comprises a plurality of almost blank subframes. During majority of symbols of an almost blank subframe of a base station, signals are transmitted at an almost blank subframe power level that is different from a transmit power during a non-almost blank subframe.

Claims

1. A method comprising:

transmitting, by a base station, a message comprising a subframe allocation bitmap indicating a plurality of Almost Blank Subframes, the plurality of Almost Blank Subframes consisting of third and eighth subframes of every radio frame in a plurality of radio frames; and

transmitting to a wireless device a unicast message comprising;

a first measurement subframe allocation bitmap indicating a first plurality of measurement subframes of a primary carrier, the first plurality of measurement subframes excluding the plurality of Almost Blank Subframes; and

a second measurement subframe allocation bitmap indicating a second plurality of measurement subframes of the primary carrier, the second plurality of measurement subframes excluding the first plurality of measurement subframes; and

wherein during a majority of symbols of an Almost Blank Subframe;

signals are transmitted at an Almost Blank Subframe power level that is lower than a transmit power during a non-Almost Blank Subframe.

2. The method of claim 1, wherein the unicast message further configures measurement subframes of a plurality neighboring carriers for the wireless device.

3. The method of claim 1, wherein the wireless device periodically reports channel state information for subframes indicated in the first measurement subframe allocation bitmap.

4. The method of claim 1, wherein the wireless device periodically reports channel state information for subframes indicated in the second measurement subframe allocation bitmap.

5. The method of claim 1, further comprising transmitting during an Almost Blank Subframe, a common reference signal only in a control region.

6. The method of claim 1, wherein each radio frame in the plurality of radio frames is assigned a system frame number (SFN) and is divided into N subframes, N being an integer greater than one.

7. The method of claim 1, wherein the message further comprises:

a subframe allocation repetition period in terms of n radio frames, n being an integer greater than or equal to one; and

a subframe allocation offset i, i being an integer greater than or equal to zero.

8. The method of claim 7, wherein the subframe allocation bitmap indicates a plurality of subframes in k frames, k being an integer and 1≦

k≦

n, the bitmap applying to subframes in k frames starting from frames whose SFN meets (SFN mod n=i) criterion.

9. A method comprising:

transmitting, by a base station, a message comprising a subframe allocation bitmap indicating a plurality of Almost Blank Subframes, the plurality of Almost Blank Subframes consisting of third, seventh, and ninth subframes of every radio frame in a plurality of radio frames; and

transmitting to a wireless device a unicast message comprising;

a first measurement subframe allocation bitmap indicating a first plurality of measurement subframes of a primary carrier, the first plurality of measurement subframes excluding the plurality of Almost Blank Subframes; and

a second measurement subframe allocation bitmap indicating a second plurality of measurement subframes of the primary carrier, the second plurality of measurement subframes excluding the first plurality of measurement subframes; and

wherein during a majority of symbols of an Almost Blank Subframe;

signals are transmitted at an Almost Blank Subframe power level that is lower than a transmit power during a non-Almost Blank Subframe.

10. The method of claim 9, further comprising transmitting during an Almost Blank Subframe, a common reference signal only in a control region.

11. The method of claim 9, wherein each radio frame in the plurality of radio frames is assigned a system frame number (SFN) and is divided into N subframes, N being an integer greater than one.

12. The method of claim 9, wherein the message further comprises:

a subframe allocation repetition period in terms of n radio frames, n being an integer greater than or equal to one; and

a subframe allocation offset i, i being an integer greater than or equal to zero.

13. The method of claim 12, wherein the subframe allocation bitmap indicates a plurality of subframes in k frames, k being an integer and 1≦

k≦

n, the bitmap applying to subframes in k frames starting from frames whose SFN meets (SFN mod n=i) criterion.

14. The method of claim 13, wherein n is equal to 2^j, and j is one of the following numbers:

0, 1, 2, 3, 4, and 5.

15. The method of claim 13, wherein the base station broadcasts:

the system frame number represented by m bits;

the p most significant bits of the system frame number employing a plurality of subcarriers in the in the middle of a frequency band of a carrier; and

the (m−

p) least significant bits of the system frame number by encoding control blocks in the physical broadcast channel over 2^(m-p) frames, sequential position of the encoded control blocks determining the (m−

p) least significant bits.

16. A method comprising:

transmitting, by a base station, a message comprising a subframe allocation bitmap indicating a plurality of Almost Blank Subframes, the plurality of Almost Blank Subframes consisting of second, fourth and eighth subframes of every radio frame in a plurality of radio frames; and

transmitting to a wireless device a unicast message comprising;

a first measurement subframe allocation bitmap indicating a first plurality of measurement subframes of a primary carrier, the first plurality of measurement subframes excluding the plurality of Almost Blank Subframes; and

a second measurement subframe allocation bitmap indicating a second plurality of measurement subframes of the primary carrier, the second plurality of measurement subframes excluding the first plurality of measurement subframes; and

wherein during a majority of symbols of an Almost Blank Subframe;

signals are transmitted at an Almost Blank Subframe power level that is lower than a transmit power during a non-Almost Blank Subframe.

17. The method of claim 16, wherein the unicast message further configures measurement subframes of a plurality neighboring carriers for the wireless device.

18. The method of claim 16, wherein the wireless device periodically reports channel state information for subframes indicated in the first measurement subframe allocation bitmap.

19. The method of claim 16, wherein the wireless device periodically reports channel state information for subframes indicated in the second measurement subframe allocation bitmap.

20. The method of claim 16, further comprising one of the following:

after a decrease in traffic load of the base station by an amount greater than a first value, transmitting a second message comprising a second subframe allocation bitmap indicating a second plurality of Almost Blank Subframes, the second plurality of Almost Blank Subframes consisting of second, fourth, seventh, and ninth subframes of every radio frame in a second plurality of radio frames; and

after an increase in traffic load of the base station by an amount greater than a second value, transmitting a third message comprising a third subframe allocation bitmap indicating a third plurality of Almost Blank Subframes, the third plurality of Almost Blank Subframes consisting of third and eighth subframes of every radio frame in a third plurality of radio frames.