Multiplex time division duplex (TDD) sync detection module

1. A repeater comprising:

a first port;

a second port;

a first amplification and filtering path coupled between the first port and the second port, wherein the first amplification and filtering path is configured to amplify and filter a first time division duplex (TDD) uplink (UL) signal in a first frequency range;

a second amplification and filtering path coupled between the first port and the second port, wherein the second amplification and filtering path is configured to amplify and filter a first TDD downlink (DL) signal in the first frequency range;

a third amplification and filtering path coupled between the first port and the second port, wherein the third amplification and filtering path is configured to amplify and filter a second TDD UL signal in a second frequency range; and

a fourth amplification and filtering path coupled between the first port and the second port, wherein the fourth amplification and filtering path is configured to amplify and filter a second TDD DL signal in the second frequency range; and

a modem configured to:

receive, for the TDD UL signal and the TDD DL signal, synchronization information for the first frequency range and UL/DL configuration information for the first frequency range;

generate an UL/DL indication signal for the first frequency range from the synchronization information and the UL/DL configuration information for the first frequency range; and

send the UL/DL indication signal to the repeater;

receive the UL/DL indication signal at the repeater for the first frequency range;

generate a switching signal for a first set of one or more switches to switch between the first amplification and filtering path and the second amplification and filtering path based on the UL/DL indication signal; and

send the switching signal to the first set of one or more switches to enable amplification of the first TDD UL signal or the first TDD DL signal;

generate a second UL/DL indication signal for the second frequency range; and

send the second UL/DL indication signal to the repeater.

2. The repeater of claim 1 , wherein the repeater is further configured to:

receive the second UL/DL indication signal for the second frequency range;

generate a second switching signal for a second set of one or more switches to switch between the third amplification and filtering path and the fourth amplification and filtering path based on the second UL/DL indication signal; and

send the second switching signal to the second set of one or more switches to enable amplification of the second TDD UL signal or the second TDD DL signal.

3. The repeater of claim 1 , wherein the repeater is further configured to:

use the UL/DL indication signal to switch between:

the first TDD UL signal; and

the first TDD DL signal.

4. The repeater of claim 1 , wherein the modem is further configured to:

receive synchronization information for the first frequency range to enable the controller to switch between:

the first TDD UL signal; and

the first TDD DL signal.

5. The repeater of claim 4 , wherein the modem is further configured to:

receive synchronization information for the first frequency range from a base station transmitting the first TDD DL signal.

6. The repeater of claim 1 , wherein the repeater is further configured to:

use the UL/DL indication signal for the first frequency range to switch between the first TDD UL signal and the first TDD DL signal, wherein the UL/DL indication signal is generated from synchronization information for the first frequency range and UL/DL configuration information for the first frequency range.

7. The repeater of claim 1 , wherein the modem is further configured to:

store the UL/DL indication signal for the first frequency range.

8. The repeater of claim 7 , wherein the modem is further configured to:

use the UL/DL indication signal for the first frequency range that is stored at the modem to reacquire UL/DL indication information for the first frequency range in a subsequent time period.

9. The repeater of claim 1 , wherein the UL/DL indication signal is generated from synchronization information for the first frequency range and UL/DL configuration information for the first frequency range.

10. The repeater of claim 1 , wherein the first frequency range includes:

one or more of: Third Generation Partnership Project (3GPP) long term evolution (LTE) time division duplex (TDD) frequency bands 33-53; or

one or more of: 3GPP fifth generation (5G) TDD frequency bands n34, n38, n39, n40, n41, n50, n51, n77, n78, n79, n257, n258, n260, or n261.

11. The repeater of claim 1 , wherein the modem is further configured to generate the UL/DL indication signal for the first frequency range without a subscriber identity module (SIM) card.

12. The repeater of claim 1 , wherein the modem comprises a long term evolution (LTE) layer- 1 modem configured to generate the UL/DL indication signal without using LTE layer-2 or LTE layer-3.

13. The repeater of claim 1 , wherein the repeater is further configured to:

switch from the first TDD DL signal to the first TDD UL signal directly within a first selected time period after downlink pilot time slot (DwPTS) symbols in a special subframe of the first TDD DL signal; and

switch from the first TDD UL signal to the first TDD DL signal within a second selected time period after a subframe boundary between a UL subframe of the first TDD signal and a DL subframe of the first TDD DL signal.

14. The repeater of claim 13 , wherein:

the first selected time period is less than one or more of: 1 mcs, 500 nanoseconds, 300 nanoseconds, 200 nanoseconds, or 100 nanoseconds; and

the second selected time period is less than one or more of: 1 mcs, 500 nanoseconds, 300 nanoseconds, 200 nanoseconds, or 100 nanoseconds.

15. The repeater of claim 13 , wherein the repeater is further configured to:

switch from the first TDD DL signal to the first TDD UL signal without using a timing advance (TA) value received from the UE; or

switch from the first TDD UL signal to the first TDD DL signal without using the TA value received from the UE.