Special subframe allocation

1. A method comprising:

a) providing, by a first base station, an overlapping coverage area with each of a plurality of second base stations, said first base station being of a different base station type than said plurality of second base stations;

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

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

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

iii) a first subframe allocation bitmap indicating a first 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 first plurality of subframes comprising a first plurality of special subframes; and

c) transmitting, by each of said plurality of second base stations, a second message to a second plurality of wireless devices in connected mode, for each of said plurality of second base stations, said second message comprising said first subframe allocation repetition period, said first subframe allocation offset, and a second subframe allocation bitmap indicating a second plurality of subframes, said second plurality of subframes comprising a second plurality of special subframes; and

wherein:

i) base stations in said plurality of second base stations configure the same set of subframes as said second plurality of special subframes;

ii) said first plurality of special subframes and said second plurality of special subframes do not substantially overlap in time; and

iii) during a majority of symbols of a special subframe of a base station:

(1) no signal being transmitted by said base station; or

(2) 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 , wherein said base station type is one of the following:

a) a femto base station type;

b) a pico base station type;

c) a micro base station type; and

d) a macro base station type.

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

4. The method of claim 1 , wherein n is equal to 2 j and j is one of the following numbers: 0, 1, 2, 3, 4, and 5.

5. The method of claim 1 , wherein said first message and said second message are broadcasted using physical downlink shared channel.

6. The method of claim 1 , further comprising transmitting a plurality of unicast messages to a subset of said first plurality of wireless devices, said plurality of unicast messages configuring:

a) measurement subframes of a primary carrier for said subset of said first plurality of wireless devices; and

b) measurement subframes of a plurality of neighboring carriers for said subset of said first plurality of wireless devices.

7. The method of claim 1 , wherein said first base station decreases the number of special subframes in said first plurality of special subframes in response to an increase in the traffic load of said first base station by an amount greater than a load value.

8. The method of claim 1 , wherein said first base station increases the number of special subframes in said first plurality of special subframes in response to a decrease in the traffic load of said first base station by an amount greater than a load value.

9. The method of claim 1 , further comprising said first base station transmitting a message to each of said at least one second base station, said message comprising a first pattern bitmap indicating a first special subframe allocation.

10. The method of claim 9 , wherein said message further comprises a second pattern bitmap indicating a subset of a first plurality of special subframes, said second pattern bitmap employed to configure measurement parameters for a subset of said second plurality of wireless devices.

11. The method of claim 1 , wherein frame and subframe transmission of said first base station and each of said second plurality of base stations are substantially synchronized.

12. A method comprising:

a) providing, by a first base station, an overlapping coverage area with each of a plurality of second base stations, said first base station being of a different base station type than said plurality of second base stations;

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

i) a first subframe allocation repetition period;

ii) a first subframe allocation offset; and

iii) a first subframe allocation bitmap indicating a first plurality of subframes, said first plurality of subframes comprising a first plurality of special subframes; and

c) transmitting, by each of said plurality of second base stations, a second message to a second plurality of wireless devices in connected mode, for each of said plurality of second base stations, said second message comprising said first subframe allocation repetition period, said first subframe allocation offset, and a second subframe allocation bitmap indicating a second plurality of subframes, said second plurality of subframes comprising a second plurality of special subframes different from said first plurality of special subframes; and

wherein:

i) base stations in said plurality of second base stations configure the same set of subframes as said second plurality of special subframes;

ii) said first plurality of special subframes and said second plurality of special subframes do not substantially overlap in time; and

iii) during a majority of symbols of a special subframe of a base station:

(1) no signal being transmitted by said base station; or

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

13. The method of claim 12 , wherein said base station type is one of the following:

a) a femto base station type;

b) a pico base station type;

c) a micro base station type; and

d) a macro base station type.

14. The method of claim 12 , wherein said first base station decreases the number of special subframes in said first plurality of special subframes in response to an increase in the traffic load of said first base station by an amount greater than a load value.

15. The method of claim 12 , further comprising said first base station transmitting a message to each of said at least one second base station, said message comprising a first pattern bitmap indicating said first special subframe allocation.

16. The method of claim 12 , further comprising transmitting in said special subframe, a common reference signal only in a control region.