Dynamic special subframe allocation

• US 9,049,724 B2
• Filed: 10/27/2012
• Issued: 06/02/2015
• 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:
  US13/662,458
• Publication Number:
  US 20130107704A1
• Time in Patent Office: 948 Days
• Field of Search: 370328-339, 370431-473, 375130-140
• US Class Current: 1/1
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04H 20/33 by plural channels
• CPC Class Codes: H04J 11/00 Orthogonal multiplex systems, e.g. using WALSH codesH04J13/00 takes precedence
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 24/06 Testing, supervising or monitoring using simulated traffic
• 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 72/52 based on load
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

A base station transmits a message to wireless devices in connected mode. The message comprises an initial subframe allocation bitmap indicating an initial plurality of subframes including an initial plurality of special subframes. After an increase in the number of wireless devices or traffic load by an amount greater than a load value, the base station transmits a second message. The second message comprises an updated subframe allocation bitmap indicating a second plurality of subframes including an updated plurality of special subframes. The updated plurality of special subframes includes a smaller number of special subframes than the initial plurality of special subframes.

Claims

1. A method comprising:

a) transmitting, by a first base station, a first message to a first plurality of wireless devices in connected mode, said first message comprising an initial first subframe allocation bitmap indicating an initial first plurality of subframes, said initial first plurality of subframes comprising an initial first plurality of special subframes;

b) transmitting, by each of at least one second base station, a second message to a second plurality of wireless devices in connected mode, for each of said at least one second base station, said second message comprising an initial second subframe allocation bitmap indicating an initial second plurality of subframes, said initial second plurality of subframes comprising an initial second plurality of special subframes, coverage area of said first base station overlapping coverage area of each of said at least one second base station; and

c) after an increase in the traffic load carried by said first base station by an amount greater than a load value;

i) transmitting, by said first base station, a third message, said third message comprising an updated first subframe allocation bitmap indicating an updated first plurality of subframes, said updated first plurality of subframes comprising an updated first plurality of special subframes, said updated first plurality of special subframes comprising a smaller number of special subframes than said initial first plurality of special subframes; and

ii) transmitting, by each of said at least one second base station, a fourth message, said fourth message comprising an updated second subframe allocation bitmap indicating an updated second plurality of subframes, said updated second plurality of subframes comprising an updated second plurality of special subframes, said updated second plurality of special subframes comprising a greater number of special subframes than said initial second plurality of special subframes; and

wherein during a majority of symbols of a special subframe of a base station;

no signal is transmitted by said base station;

or signals are transmitted at a special subframe power level that is substantially lower than a transmit power during a non-special subframe.

2. The method of claim 1, further comprising, transmitting in said special subframe, a common reference signal only in a control region.

3. The method of claim 1, wherein base stations in said plurality of second base stations:

a) configure the same set of subframes as said initial second plurality of special subframes; and

b) configure the same set of subframes as said updated second plurality of special subframes.

4. The method of claim 1, wherein said first message, said second message, and said fourth message are broadcast employing a physical downlink shared channel.

5. The method of claim 1, wherein traffic load carried by said first base station increases when the number of said first plurality of wireless devices increases.

6. The method of claim 1, wherein traffic load carried by said first base station increases, when downlink or uplink radio resource utilization increases.

7. The method of claim 1, further comprising transmitting, by said first base station, a message to each of said at least one second base station after an increase in the traffic load carried by said first base station, said message comprising a first pattern bitmap indicating an updated first special subframe allocation.

8. The method of claim 7, wherein said message further comprises a second pattern bitmap indicating a subset of said updated first special subframes, said second pattern bitmap employed to configure measurement parameters for a subset of said second plurality of wireless devices.

9. A method comprising:

a) transmitting, by a base station, a first message to a plurality of wireless devices in connected mode, said first message comprising;

i) an initial subframe allocation repetition period in terms of n frames, n being an integer greater than or equal to one, each frame being assigned a system frame number (SFN);

ii) an initial subframe allocation offset i, i being an integer greater than or equal to zero; and

iii) an initial subframe allocation bitmap indicating an initial plurality of subframes in k frames, k being an integer where 1≦

k≦

n, said bitmap applying to subframes in k frames starting from frames whose SFN meets (SFN mod n =i) criterion, said initial plurality of subframes comprising an initial plurality of special subframes; and

b) transmitting, by said base station, a second message after an increase in the number of said plurality of wireless devices by an amount greater than a load value, said second message comprising;

i) said initial subframe allocation repetition period;

ii) said initial subframe allocation offset; and

iii) an updated subframe allocation bitmap indicating a second plurality of subframes, said second plurality of subframes comprising an updated plurality of special subframes, said updated plurality of special subframes comprising a smaller number of special subframes than said initial plurality of special subframes; and

wherein during a majority of symbols of a special subframe of said base station;

no signal is transmitted by said base station;

or signals are transmitted at a special subframe power level that is substantially lower than a transmit power during a non-special subframe.

10. The method of claim 9, wherein n is equal to 2^j and j is one of the following numbers:

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

11. The method of claim 9, further comprising broadcasting, by said base station, said system frame number represented by m bits during each frame.

12. The method of claim 9, further comprising broadcasting, by said base station, the p most significant bits of said system frame number using a plurality of subcarriers in the middle of the frequency band of a carrier.

13. The method of claim 12, further comprising transmitting, by said base station, 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.

14. The method of claim 9, further comprising transmitting, by said base station, a message to each of at least one second base station after an increase in the traffic load carried by said base station by an amount greater than said load value, said message comprising a first pattern bitmap indicating said updated first special subframe allocation.

15. The method of claim 9, further comprising, transmitting in said special subframe, a common reference signal only in a control region.

16. A base station comprising:

a) one or more communication interfaces;

b) one or more processors; and

c) memory storing instructions that, when executed, cause said base station to;

i) transmit a first message to a plurality of wireless devices in connected mode, said first message comprising;

(1) an initial subframe allocation repetition period;

(2) an initial subframe allocation offset; and

(3) an initial subframe allocation bitmap indicating an initial plurality of subframes, said initial plurality of subframes comprising an initial plurality of special subframes; and

ii) transmit a second message after an increase in the traffic load of said base station by an amount greater than a load value, said second message comprising;

(1) said initial subframe allocation repetition period;

(2) said initial subframe allocation offset; and

(3) an updated subframe allocation bitmap different from said initial subframe allocation bitmap, said updated subframe allocation bitmap indicating a second plurality of subframes, said second plurality of subframes comprising an updated plurality of special subframes, said updated plurality of special subframes comprising a smaller number of special subframes than said initial plurality of special subframes; and

wherein during a majority of symbols of a special subframe of said base station;

no signal is transmitted by said base station;

or signals are transmitted at a special subframe power level that is substantially lower than a transmit power during a non-special subframe.

17. The base station of claim 16, wherein said instructions, when executed, further cause said base station transmit a message to each of at least one second base station after an increase in the traffic load carrier by said base station by an amount greater than said load value, said message comprising a first pattern bitmap indicating an updated first special subframe allocation.

18. The base station of claim 17, wherein said message further comprises a second pattern bitmap indicating a subset of said updated first special subframes, said second pattern bitmap employed to configure measurement parameters for a subset of said second plurality of wireless devices.

19. The base station of claim 16, wherein traffic load carried by said base station increases when the number of said first plurality of wireless devices increases.

20. The base station of claim 16, wherein traffic load carried by said base station increases when downlink or uplink radio resource utilization increases.