Wireless Transceivers with Filter Arrangement for WiFi and WiMAX Coexsistence

• US 20120044919A1
• Filed: 08/17/2011
• Published: 02/23/2012
• Est. Priority Date: 08/17/2010
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Fujimoto, William, Compton, Richard, MEDAPALLI, Kamesh, Stauffer, Erik, Hochwald, Bertrand, Saada, Yossi (Joseph)
• Granted Patent: US 8,681,748 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

Embodiments provide WiFi and WiMAX tailored transceiver radio frequency (RF) filtering techniques and configurations to enable coexistence between WiFi and WiMAX transceivers operating in close proximity. In particular, embodiments provide filtering techniques to reject emissions from WiMAX into WiFi, and vice versa. The filtering techniques eliminate the need for additional isolation between WiMAX and WiFi antennas (approximately 50 dB), which is beyond what is achievable in practice. Embodiments can be tailored according to different use cases of the WiFi and WiMAX transceivers (e.g., fixed CPE, portable router, smart phone with tethering).

Claims

1. A WiFi/WiMAX (WiWi) device, comprising:

a WiMAX transceiver; and

a WiFi transceiver;

wherein the WiMAX transceiver comprises;

a WiMAX radio frequency (RF) integrated circuit (RFIC); and

a first RF analog front end, coupled to the WiMAX RFIC;

wherein the first RF analog front end comprises;

a WiMAX transmit path, including a first WiMAX band-pass filter (BPF) and a first power amplifier (PA), the first WiMAX BPF placed before the first PA in the WiMAX transmit path; and

first and second WiMAX receive paths, each including a first low-noise amplifier (LNA) and a second WiMAX BPF, the second WiMAX BPF placed before the first LNA in the first and second receive paths.

2. The WiWi device of claim 1, wherein the first RF analog front end further comprises:

a first T/R switch that couples the first WiMAX receive path and the WiMAX transmit path to a first antenna; and

a second T/R switch that couples the second WiMAX receive path and the WiMAX transmit path to a second antenna.

3. The WiWi device of claim 2, wherein the WiMAX transmit path further comprises:

a transmit (TX) diversity switch, placed after the first PA in the WiMAX transmit path, that couples the WiMAX transmit path to the first and second T/R switches, thereby allowing the WiMAX transceiver to transmit using both the first antenna and the second antenna.

4. The WiWi device of claim 1, wherein the first WiMAX BPF band-pass filters WiMAX transmissions from the WiMAX RFIC to reduce emissions outside of a WiMAX frequency band contained in the WiMAX transmissions, thus protecting the WiFi transceiver from said emissions.

5. The WiWi device of claim 1, wherein the second WiMAX BPF band-pass filters received signals to reduce emissions outside of a WiMAX frequency band contained in the received signals, thus protecting the WiMAX transceiver from said emissions.

6. The WiWi device of claim 1, wherein the WiFi transceiver comprises:

a WiFi RFIC; and

a second RF analog front end, coupled to the WiFi RFIC;

wherein the second RF analog front end comprises;

a WiFi transmit path, including a second PA;

a WiFi receive path, including a second LNA;

a transmit/receive (T/R) switch that couples the WiFi transmit path and the WiFi receive path to an antenna; and

a WiFi BPF placed between the T/R switch and the antenna.

7. The WiWi device of claim 6, wherein the WiFi BPF band-pass filters WiFi transmissions from the WiFi RFIC to reduce emissions outside of a WiFi channel contained in the WiFi transmissions, thus protecting the WiMAX transceiver from said emissions.

8. The WiWi device of claim 6, wherein the WiFi BPF band-pass filters signals received from the antenna to reduce emissions outside of a WiFi channel contained in said signals, thus protecting the WiFi transceiver from said emissions.

9. The WiWi device of claim 1, wherein the WiWi device communicates, via the WiMAX transceiver, with a WiMAX base station.

10. The WiWi device of claim 9, wherein communication between the WiWi device and the WiMAX base station is in accordance with the IEEE 802.16 standard.

11. The WiWi device of claim 1, wherein the WiWi device communicates, via the WiFi transceiver, with a WiFi device.

12. The WiWi device of claim 11, wherein communication between the WiWi device and the WiFi device is in accordance with the IEEE 802.11 standard.

13. The WiWi device of claim 1, wherein the WiWi device is one of a WiWi Customer Premises Equipment (CPE), a WiWi portable router, and a phone with a tethering feature.

14. The WiWi device of claim 1, wherein an input of the first WiMAX BPF is coupled to an output of the WiMAX RFIC, and an output of the first WiMAX BPF is coupled to an input of the first PA.

15. The WiWi device of claim 1, wherein an output of the second WiMAX BPF is coupled to an input of the first LNA.

16. A WiFi/WiMAX (WiWi) device, comprising:

a WiMAX transceiver; and

a WiFi transceiver;

wherein the WiMAX transceiver comprises;

a WiMAX radio frequency (RF) integrated circuit (RFIC); and

a first RF analog front end, coupled to the WiMAX RFIC;

wherein the first RF analog front end comprises;

a WiMAX transmit path, including a first power amplifier (PA); and

first and second WiMAX receive paths, each including a roofing filter, a first low-noise amplifier (LNA), and a first WiMAX notch filter, the roofing filter placed before the first LNA and the first WiMAX notch filter placed after the LNA in the first and second receive paths.

17. The WiWi device of claim 16, wherein the first RF analog front end further comprises:

a first T/R switch that couples the first WiMAX receive path and the WiMAX transmit path to a first antenna; and

a second T/R switch that couples the second WiMAX receive path and the WiMAX transmit path to a second antenna.

18. The WiWi device of claim 17, wherein the WiMAX transmit path further comprises:

a transmit (TX) diversity switch, placed after the first PA in the WiMAX transmit path, that couples the WiMAX transmit path to the first and second T/R switches, thereby allowing the WiMAX transceiver to transmit using both the first antenna and the second antenna.

19. The WiWi device of claim 16, wherein the WiMAX transmit path further comprises:

a second WiMAX notch filter placed before the first PA in the WiMAX transmit path.

20. The WiWi device of claim 19, wherein the second WiMAX notch filter notches out emissions in a WiFi band from transmissions from the WiMAX RFIC, thus protecting the WiFi transceiver from said emissions.

21. The WiWi device of claim 16, wherein the first WiMAX notch filter notches out emissions in a WiFi band from received signals, thus protecting the WiMAX transceiver from said emissions.

22. The WiWi device of claim 16, wherein the roofing filter is a high-pass filter that reduces emissions below a WiFi band in received signals.

23. The WiWi device of claim 16, wherein the WiWi device is one of a WiWi Customer Premises Equipment (CPE), a WiWi portable router, and a phone with a tethering feature.

24. The WiWi device of claim 16, wherein the WiFi transceiver comprises:

a WiFi RFIC; and

a second RF analog front end, coupled to the WiFi RFIC;

wherein the second RF analog front end comprises;

a WiFi transmit path, including a second PA;

a WiFi receive path, including a second LNA;

a transmit/receive (T/R) switch that couples the WiFi transmit path and the WiFi receive path to an antenna; and

a WiFi BPF placed between the T/R switch and the antenna.

25. A WiFi/LTE device, comprising:

a LTE transceiver; and

a WiFi transceiver;

wherein the LTE transceiver comprises;

a LTE radio frequency (RF) integrated circuit (RFIC); and

a first RF analog front end, coupled to the LTE RFIC;

wherein the first RF analog front end comprises;

a LTE transmit path, including a first LTE band-pass filter (BPF) and a first power amplifier (PA), the first LTE BPF placed before the first PA in the LTE transmit path; and

first and second LTE receive paths, each including a first low-noise amplifier (LNA) and a second LTE BPF, the second LTE BPF placed before the first LNA in the first and second receive paths.