Efficient almost blank subframe allocation

• US 9,295,060 B2
• Filed: 12/18/2014
• Issued: 03/22/2016
• Est. Priority Date: 10/29/2011
• Status: Active Grant

• Current Assignee: Comcast Cable Communications LLC (Comcast Corporation)
• Original Assignee: Ofinno Technologies, LLC
• Inventors: Dinan, Esmael Hejazi
• Primary Examiner(s): Zaidi, Iqbal
• Application Number:
  US14/574,709
• Publication Number:
  US 20150139134A1
• Time in Patent Office: 460 Days
• Field of Search: 370328-339, 370433-473, 370130-140
• 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, no signal is transmitted by the base station or 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 for use by a base station, the method comprising:

a) transmitting a message comprising a subframe allocation bitmap indicating a plurality of Almost Blank Subframes, said plurality of Almost Blank Subframes consisting of second, fourth, seventh, and ninth subframes of every radio frame in a plurality of radio frames; and

b) transmitting to a wireless device a unicast message comprising;

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

ii) a second measurement subframe allocation bitmap indicating a second plurality of measurement subframes of said primary carrier, said second plurality of measurement subframes excluding any of the subframes in said 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, further comprising transmitting during an Almost Blank Subframe, a common reference signal only in a control region.

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

4. The method of claim 1, wherein said message further comprises:

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

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

5. The method of claim 4, wherein said subframe allocation bitmap indicates a plurality of subframes in k frames, k being an integer and 1≦

k≦

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

6. The method of claim 5, wherein n is equal to 2^j, and j is one of the following numbers:

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

7. The method of claim 5, wherein said base station broadcasts:

a) said system frame number represented by m bits;

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

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

8. A method for use by a base station, the method comprising:

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

b) transmitting to a wireless device a unicast message comprising;

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

ii) a second measurement subframe allocation bitmap indicating a second plurality of measurement subframes of said primary carrier, said second plurality of measurement subframes excluding any of the subframes in said 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.

9. The method of claim 8, wherein said unicast message further configures measurement subframes of a plurality neighboring carriers for said wireless device.

10. The method of claim 8, wherein said wireless device periodically reports channel state information for subframes indicated in said first measurement subframe allocation bitmap.

11. The method of claim 8, wherein said wireless device periodically reports channel state information for subframes indicated in said second measurement subframe allocation bitmap.

12. The method of claim 8, further comprising transmitting during an Almost Blank Subframe, a common reference signal only in a control region.

13. The method of claim 8, wherein each radio frame in said plurality of radio frames is assigned a system frame number (SFN) and is divided into N subframes, N being an integer greater than one.

14. The method of claim 8, wherein said message further comprises:

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

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

15. The method of claim 14, wherein said subframe allocation bitmap indicates a plurality of subframes in k frames, k being an integer and 1≦

k≦

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

16. A method for use by a base station, the method comprising:

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

b) transmitting to a wireless device a unicast message comprising;

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

iv) a second measurement subframe allocation bitmap indicating a second plurality of measurement subframes of said primary carrier, said second plurality of measurement subframes excluding any of the subframes in said 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 said unicast message further configures measurement subframes of a plurality neighboring carriers for said wireless device.

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

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

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

a) after a decrease in traffic load of said 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, said 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

b) after an increase in traffic load of said 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, said third plurality of Almost Blank Subframes consisting of third and eighth subframes of every radio frame in a third plurality of radio frames.