Radio frequency front end modules implementing coexisting time division duplexing and frequency division duplexing
Radio frequency front end modules implementing coexisting time division duplexing and frequency division duplexing are provided. In one aspect, a front end system includes a time-division duplexing transmit terminal, a time-division duplexing receive terminal, a frequency division duplexing terminal, and an antenna terminal. The front end system further includes first, second, and third switches configured to selectively connect the terminals to either a node or the antenna. The front end system also includes a controller configured to provide delays between disconnecting the terminals from the antenna and connecting the terminals to the node.
1. A wireless front end system comprising:
time-division duplexing transmit and receive terminals, a frequency division duplexing terminal, and an antenna terminal;
a first switch configured to selectively connect the time-division duplexing transmit terminal to either a first node or the antenna based on a first control signal, a second switch configured to selectively connect the time-division duplexing receive terminal to either a second node or the antenna based on a second control signal, and a third switch configured to connect the frequency division duplexing terminal to the antenna based on a third control signal; and
a controller configured to generate the first, second, and third control signals, and to provide: i) a first delay between switching connection of the time-division duplexing transmit terminal from the antenna to the first node, and ii) a second delay between switching connection of the time-division duplexing receive terminal from the antenna to the second node.
2. The front end system of claim 1 wherein the first node and the second node are ground nodes.
3. The front end system of claim 1 wherein the first switch includes a first serial sub-switch configured to selectively connect the time-division duplexing transmit terminal to the antenna and a first shunt sub-switch configured to selectively connect the time-division duplexing transmit terminal to the first node, and the second switch includes a second serial sub-switch configured to selectively connect the time-division duplexing receive terminal to the antenna and a second shunt sub-switch configured to selectively connect the time-division duplexing receive terminal to the second node.
4. The front end system of claim 3 wherein the first control signal includes a first serial control signal configured to control the first serial sub-switch and a first shunt control signal configured to control the first shunt sub-switch, and the second control signal includes a second serial control signal configured to control the second serial sub-switch and a second shunt control signal configured to control the second shunt sub-switch.
5. The front end system of claim 4 wherein the controller is further configured to provide the first delay between transitioning the first serial control signal to an off value and transitioning the first shunt control signal to an on value, and the controller is further configured to provide the second delay between transitioning the second serial control signal to the off value and transitioning the second shunt control signal to the on value.
6. The front end system of claim 5 wherein the controller is further configured to provide a third delay between transitioning the first shunt control signal to the off value and transitioning the first serial control signal to the on value, and the controller is further configured to provide a fourth delay between transitioning the second shunt control signal to the off value and transitioning the second serial control signal to the on value.
7. The front end system of claim 1 wherein the controller is further configured to adjust a length of the first delay and the second delay.
8. The front end system of claim 1 wherein the controller includes both digital and analog circuitry configured to implement the first delay and the second delay.
9. The front end system of claim 1 wherein the controller is further configured to switch between connecting the time-division duplexing transmit terminal and the time-division duplexing receive terminal to the antenna while the frequency division duplexing terminal remains connected to the antenna.
10. A mobile device comprising:
an antenna configured to transmit radio frequency signals to a base station;
a time-division duplexing power amplifier, a time-division duplexing low noise amplifier, and a frequency division duplexing terminal; and
a front end system coupled to the antenna, the time-division duplexing power amplifier, the time-division duplexing low noise amplifier, and the frequency division duplexing terminal, the front end system including a first switch configured to selectively connect the time-division duplexing power amplifier to either a first node or the antenna based on a first control signal, a second switch configured to selectively connect the time-division duplexing low noise amplifier to either a second node or the antenna based on a second control signal, a third switch configured to connect the frequency division duplexing terminal to the antenna based on a third control signal, and a controller configured to generate the first, second, and third control signals, to provide: i) a first delay between switching connection of the time-division duplexing power amplifier from the antenna to the first node, and ii) a second delay between switching connection of the time-division duplexing low noise amplifier from the antenna to the second node.
11. The mobile device of claim 10 wherein the first node and the second node are ground nodes.
12. The mobile device of claim 10 wherein the first switch includes a first serial sub-switch configured to selectively connect the time-division duplexing power amplifier to the antenna and a first shunt sub-switch configured to selectively connect the time-division duplexing power amplifier to the first node, and the second switch includes a second serial sub-switch configured to selectively connect the time-division duplexing low noise amplifier to the antenna and a second shunt sub-switch configured to selectively connect the time-division duplexing low noise amplifier to the second node.
13. The mobile device of claim 12 wherein the first control signal includes a first serial control signal configured to control the first serial sub-switch and a first shunt control signal configured to control the first shunt sub-switch, and the second control signal includes a second serial control signal configured to control the second serial sub-switch and a second shunt control signal configured to control the second shunt sub-switch.
14. The mobile device of claim 13 wherein the controller is further configured to provide the first delay between transitioning the first serial control signal to an off value and transitioning the first shunt control signal to an on value, and the controller is further configured to provide the second delay between transitioning the second serial control signal to the off value and transitioning the second shunt control signal to the on value.
15. The mobile device of claim 14 wherein the controller is further configured to provide a third delay between transitioning the first shunt control signal to the off value and transitioning the first serial control signal to the on value, and the controller is further configured to provide a fourth delay between transitioning the second shunt control signal to the off value and transitioning the second serial control signal to the on value.
16. The mobile device of claim 10 wherein the controller is further configured to adjust the length of the first delay and the second delay.
17. The mobile device of claim 10 wherein the controller includes both digital and analog circuitry configured to implement the first delay and the second delay.
18. The mobile device of claim 10 wherein the controller is further configured to switch between connecting the time-division duplexing power amplifier and the time-division duplexing low noise amplifier to the antenna while the frequency division duplexing terminal remains connected to the antenna.
19. A method of operating a radio frequency device, comprising:
coupling, via a first switch, a time-division duplexing transmit terminal to either a first node or an antenna based on a first control signal;
coupling, via a second switch, a time-division duplexing receive terminal to either a second node or the antenna based on a second control signal;
coupling, via a third switch, a frequency division duplexing terminal to the antenna based on a third control signal;
providing a first delay between switching connection of the time-division duplexing transmit terminal from the antenna to the first node; and
providing a second delay between switching connection of the time-division duplexing receiver terminal from the antenna to the second node.
20. The method of claim 19 further comprising adjusting a length of the first delay and the second delay.
21. The method of claim 19 further comprising:
selectively coupling, via a first serial sub-switch, the time-division duplexing transmit terminal to the antenna;
selectively coupling, via a first shunt sub-switch, the time-division duplexing transmit terminal to the first node;
selectively coupling, via a second serial sub-switch, the time-division duplexing receive terminal to the antenna; and
selectively coupling, a second shunt sub-switch, the time-division duplexing receive terminal to the second node.
22. The method of claim 21 further comprising:
generating a first serial control signal to control the first serial sub-switch;
generating a first shunt control signal to control the first shunt sub-switch;
generating a second serial control signal to control the second serial sub-switch; and
generating a second shunt control signal to control the second shunt sub-switch.