Mobile device front end architecture for time division duplexing

• US 10,644,861 B2
• Filed: 12/05/2017
• Issued: 05/05/2020
• Est. Priority Date: 11/06/2014
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Pehlke, David Richard
• Primary Examiner(s): Chen, Peter
• Application Number:
  US15/831,713
• Publication Number:
  US 20180205530A1
• Time in Patent Office: 882 Days
• CPC Class Codes: H04B 1/0057 using diplexing or multiplexing filters for selecting the desired band
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/1469 using time-sharing

Abstract

A switching circuit for use in a frequency division duplex (FDD) spectrum re-allocated for time division duplex (TDD) applications comprises a first filter configured to filter a TDD receive signal, a duplex filter configured to filter an FDD receive signal, and a plurality of switches configured to route the FDD receive signal from an antenna through the duplex filter to receiver circuitry and to route the TDD receive signal from the antenna through the first filter to the receiver circuitry such that the FDD and TDD receive signals share the FDD spectrum.

Claims

1. A switching circuit for use in a frequency division duplex spectrum re-allocated for time division duplex application, the switching circuit comprising:

a duplex filter configured to filter first signals including frequency and time division duplex receive and transmit signals in a reallocated transmit band;

a gap filter configured to filter time division duplex receive and transmit signals in a reallocated duplex gap band between the reallocated transmit band and a receive band; and

a plurality of switches configured to route the first signals to and from an antenna, respectively, through at least one of the duplex filter and the gap filter the first signals sharing the reallocated transmit band that includes separate sub-bands including a first sub-band allocated for frequency division duplex transmission, a second sub-band allocated for time division duplex transmission and reception, a third sub-band allocated for frequency division duplex transmission, the reallocated duplex gap band including first and second dual-use bands and a fourth sub-band interposed therebetween and allocated for time division duplex transmission and reception, the dual-use bands configured as one of a guard band or a time division duplex band based at least in part on a received signal strength indication.

2. The switching circuit of claim 1 wherein the duplex filter includes a surface acoustic wave filter.

3. The switching circuit of claim 1 wherein the duplex filter includes a band pass filter.

4. The switching circuit of claim 1 wherein the duplex filter includes a film bulk acoustic resonator filter.

5. The switching circuit of claim 1 wherein the duplex filter includes a bulk acoustic wave filter.

6. The switching circuit of claim 1 wherein the reallocated transmit band further includes a fifth sub-band interposed between the first and second sub-bands, the fifth sub-band configured to operate as a guard band when signal interference between the first sub-band and the second sub-band is greater than a threshold.

7. The switching circuit of claim 6 wherein the fifth sub-band is allocated for time division duplex transmission when the signal interference between the first sub-band and the second sub-band is less than the threshold.

8. A switching module for use in a frequency division duplex spectrum re-allocated for time division duplex application, the switching module comprising:

a switching circuit implemented in a first semiconductor die, the switching circuit including a duplex filter configured to filter first signals including frequency and time division duplex receive and transmit signals in a reallocated transmit band, a gap filter configured to filter time division duplex receive and transmit signals in a reallocated duplex gap band between the reallocated transmit band and a receive band, and a plurality of switches configured to route the first signals to and from an antenna, respectively, through at least one of the duplex filter and the gap filter, the first signals sharing the reallocated transmit band that includes separate sub-bands including a first sub-band allocated for frequency division duplex transmission, a second sub-band allocated for time division duplex transmission and reception, a third sub-band allocated for frequency division duplex transmission, the reallocated duplex gap band including first and second dual-use bands and a fourth sub-band interposed therebetween and allocated for time division duplex transmission and reception, the dual-use bands configured as one of a guard band or a time division duplex band based at least in part on a received signal strength indication; and

at least one of a prefilter circuit, a post filter circuit, a power amplifier circuit, a switch circuit, a down converter circuit, and a modulator circuit implemented in a second semiconductor die.

9. The switching module of claim 8 wherein the duplex filter includes a surface acoustic wave filter.

10. The switching module of claim 8 wherein the duplex filter includes a band pass filter.

11. The switching module of claim 8 wherein the duplex filter includes a film bulk acoustic resonator filter.

12. The switching module of claim 8 wherein the duplex filter includes a bulk acoustic wave filter.

13. The switching module of claim 8 wherein the reallocated transmit band further includes a fifth sub-band interposed between the first and second sub-bands, the fifth sub-band configured to operate as a guard band when signal interference between the first sub-band and the second sub-band is greater than a threshold.

14. The switching module of claim 13 wherein the fifth sub-band is allocated for time division duplex transmission when the signal interference between the first sub-band and the second sub-band is less than the threshold.

15. The switching module of claim 8 wherein the third sub-band configured to operate as one of a guard band and an uplink for time division duplex receive signals.

16. A method to transmit and receive frequency division duplex signals and time division duplex signals in a frequency division duplex and time division duplex shared frequency band, the method comprising:

routing first signals including frequency and time division duplex transmit and receive signals to and from an antenna, respectively, through at least one of a duplex filter and a gap filter,

filtering with the duplex filter the first signals in a reallocated transmit band;

filtering with the gap filter time division duplex receive and transmit signals in a reallocated duplex gap band between the reallocated transmit band and a receive band, the first signals sharing the reallocated transmit that includes separate sub-bands including a first sub-band allocated for frequency division duplex transmission, a second sub-band allocated for time division duplex transmission and reception, a third sub-band allocated for frequency division duplex transmission, the reallocated duplex gap band including first and second dual-use bands and a fourth sub-band interposed therebetween and allocated for time division duplex transmission and reception; and

configuring the dual-use bands as one of a guard band or a time division duplex band based at least in part on a received signal strength indication.

17. The method of claim 16 wherein the duplex filter includes a film bulk acoustic resonator filter.

18. The method of claim 16 wherein the duplex filter includes a bulk acoustic wave filter.

19. The method of claim 16 wherein the reallocated transmit band further includes a fifth sub-band interposed between the first and second sub-bands, the fifth sub-band configured to operate as a guard band when signal interference between the first sub-band and the second sub-band is greater than a threshold.

20. The method of claim 19 wherein the fifth sub-band is allocated for time division duplex transmission when the signal interference between the first sub-band and the second sub-band is less than the threshold.