Power based frame timing synchronization for a time-division duplexing network

1. A method of aligning a transmission frame in a Time Division Duplexing (TDD) network, wherein the transmission frame includes a sequence of units separated by transition points, wherein a transition point is a transition between uplink and downlink transmission and each unit includes one or more resource slots in either the uplink or downlink, the method comprising:

allocating a transmit power level to a plurality of resource slots in a unit, wherein a transmit power level for a first resource slot of the plurality of resource slots is greater than a transmit power level for a second resource slot of the plurality of resource slots;

measuring the transmit power of a TDD transmission received from an external node to determine a time period when a peak transmit power of the received TDD transmission occurs; and

aligning the first resource slot by shifting the first resource slot to coincide with a predetermined timeslot with respect to the time period when the peak transmit power of the received TDD transmission occurs.

2. The method as claimed in claim 1 , wherein the first resource slot is positioned at a center of the plurality of resource slots.

3. The method as claimed in claim 1 , wherein the second resource slot is adjacent to a transition point with another unit in the sequence of units, and the transmit power level allocated to the second resource slot is lower than the transmit power levels for each of the plurality of resource slots.

4. The method as claimed in claim 1 , wherein the transmit power levels allocated to the plurality of resource slots in the unit decrease with distance from a center of the unit.

5. The method as claimed in claim 1 , wherein the first resource slot is a timeslot.

6. The method as claimed in claim 1 , further comprising:

a first device in the TDD network sending a signal to a second device in the TDD network, the signal being configured such that the first resource slot is aligned to coincide with the peak transmit power of the received TDD transmission.

7. A non-transitory computer-readable storage medium comprising a computer program containing computer-executable code which, when executed on a computer, causes the computer to perform the method of claim 1 .

8. A device for a Time Division Duplexing (TDD) network, the device comprising:

a receiver adapted to receive a TDD transmission from an external device;

a processor adapted to configure a transmission frame, the transmission frame including a sequence of units separated by transition points, wherein a transition point is a transition between uplink and downlink transmission and each unit includes one or more resource slots in either the uplink or downlink; and

a power measurement module adapted to measure a transmit power level of the received TDD transmission and determine a time period when a peak transmit power level of the received TDD transmission occurs,

wherein the processor is further adapted to:

allocate a transmit power level to a plurality of resource slots in a unit of the transmission frame, wherein a transmit power level for a first resource slot of the plurality of resource slots is greater than a transmit power level for a second resource slot of the plurality of resource slots; and

align the first resource slot by shifting the first resource slot to coincide with a predetermined timeslot with respect to the time period when the peak transmit power of the received TDD transmission occurs.

9. The device as claimed in claim 8 , wherein the first resource slot is positioned at a center of the plurality of resource slots.

10. The device as claimed in claim 8 , wherein the second resource slot is adjacent to a transition point with another unit in the sequence of units, and the transmit power level allocated to the second resource slot is lower than the transmit power levels for each of the plurality of resource slots.

11. The device as claimed in claim 8 , wherein the transmit power levels allocated to the plurality of resource slots in the unit decrease with distance from a center of the unit.

12. The device as claimed in claim 8 , wherein the first resource slot is a timeslot.

13. The device as claimed in claim 8 , wherein the power measurement module is part of the processor.

14. The device as claimed in claim 8 , being a small cell.