Method and apparatus for aggregation of frequency division duplex and time division duplex
This application related to method and apparatus for aggregation of frequency division duplex and time division duplex. One embodiment of method comprises receiving signals from a cell configured with FDD and/or a cell configured with TDD according to the downlink scheduling, adjusting timing of uplink transmissions for the cells configured with FDD or the cell configured with TDD when the UE detects timing difference between the cells, and transmitting uplink signal to the cell configured and/or a cell configured with TDD based on the adjusted timing.
1. A method for frequency division duplex (FDD)/time division duplex (TDD) aggregation by an user equipment (UE), the method comprising:
receiving signals from a macro cell configured with FDD and a small cell configured with TDD according to downlink scheduling;
detecting timing difference between the macro cell and the small cell, based on the received signals from the macro cell and the small cell;
reporting the timing difference to a network;
receiving a timing advance (TA) value, which is configured by the network based on the timing difference, for aligning an uplink subframe of the small cell with an uplink subframe of the macro cell, from the network; and
aligning the uplink subframe of the small cell with the uplink subframe of the macro cell, based on the received TA value,
wherein the uplink subframe of the small cell colliding with a non-uplink subframe of the small cell is adjusted not to be used, when the uplink subframe of the small cell collides with the non-uplink subframe of the small cell after aligning the uplink subframe of the small cell.
2. The method of claim 1 , wherein the uplink subframe of the small cell is adjusted not to be used, by higher layer signaling.
3. The method of claim 1 , wherein the TA value is received for transmitting a random access channel.
4. The method of claim 1 , wherein the uplink subframe of the small cell is aligned with the uplink subframe of the macro cell, while a non-uplink subframe of the small cell is not adjusted.
5. The method of claim 1 , wherein the non-uplink subframe includes at least one of a special subframe or a downlink subframe, and
wherein the special subframe is a subframe including a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS).
6. The method of claim 1 , wherein transmission timing for the small cell is adjusted by an offset corresponding to an amount of subframes with which boundaries of single frequency networks configured with the UE are mis-aligned, and an uplink signal for the small cell is transmitted at the uplink subframe adjusted based on the offset.
7. A method for frequency division duplex (FDD)/time division duplex (TDD) aggregation by a base station (BS), the method comprising:
receiving timing difference from a user equipment (UE), wherein the UE is configured to receive and transmit signals from a macro cell configured with FDD and a small cell configured with TDD;
configuring a timing advance (TA) value for aligning an uplink subframe of the small cell with an uplink subframe of the macro cell, based on the received timing difference; and
transmitting the configured TA value to the UE,
wherein the uplink subframe of the small cell is aligned with the uplink subframe of the macro cell based on the TA value, and
wherein the uplink subframe of the small cell colliding with a non-uplink subframe of the small cell is adjusted not to be used, when the uplink subframe of the small cell collides with the non-uplink subframe of the small cell after aligning the uplink subframe of the small cell.
8. The method of claim 7 , further comprising:
transmitting, to the UE, subframe information indicating the uplink subframe of the small cell collided with the non-uplink subframe of the small cell.
9. The method of claim 7 , wherein the uplink subframe of the small cell is aligned with the uplink subframe of the macro cell, while a non-uplink subframe of the small cell is not adjusted.
10. The method of claim 7 , wherein the timing difference is received from the UE after the UE detects the timing difference between the macro cell and the small cell.
11. The method of claim 7 , wherein the non-uplink subframe includes at least one of a special subframe or a downlink subframe, and
wherein the special subframe is a subframe including a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS).
12. The method of claim 7 , wherein transmission timing for the small cell is adjusted by an offset corresponding to the amount of mis-alignment between the macro cell and the small cell.