Dual Frequency Band Wireless LAN

• US 20070280185A1
• Filed: 06/26/2007
• Published: 12/06/2007
• Est. Priority Date: 05/03/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Onedera, Keith, Shor, Arie, Terrovitis, Manolis, Thomson, John, Zaragari, Masoud, Su, David, McFarland, William
• Granted Patent: US 7,865,150 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H03H 7/0153 Electrical filters; Controlling thereof
• CPC Class Codes: H03H 7/48 Networks for connecting several sources or loads, working on the same frequency or frequency band, to a common load or source phase shifters providing two or more output signals H03H7/21
• CPC Class Codes: H04B 7/0602 using antenna switching H04B7/0686 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/0805 with single receiver and antenna switching H04B7/0822 takes precedence
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• 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

A dual band radio is constructed using a primary and secondary transceiver. The primary transceiver is a complete radio that is operational in a stand alone configuration. The secondary transceiver is a not a complete radio and is configured to re-use components such as fine gain control and fine frequency stepping of the primary transceiver to produce operational frequencies of the secondary transceiver. The primary transceiver acts like an intermediate frequency device for the secondary transceiver. Switches are utilized to divert signals to/from the primary transceiver from/to the secondary transceiver. The switches are also configured to act as gain control devices. Antennas are selected using either wideband or narrowband antenna switches that are configured as a diode bridge having high impedance at operational frequencies on control lines that bias the diodes.

Claims

1. A method of performing wireless LAN (WLAN) communications with a dual band WLAN device, comprising the steps of:

listening for primary communication signals in a primary frequency band;

initiating WLAN operations in the primary frequency band if a wireless LAN is detected in the primary frequency band;

listening for secondary communication signals in a secondary frequency band if primary communication signals are not detected in the primary frequency band; and

initiating WLAN operations in the secondary frequency band if a wireless LAN is detected in the secondary frequency band, wherein initiating WLAN operations in the secondary frequency band includes converting a signal from the primary frequency band to the secondary frequency band during a first operation and from the secondary frequency band to the primary frequency band during a second operation, each frequency band being defined by a standard.

2. The method according to claim 1, further comprising the step of repeating the steps of listening and initiating if no WLAN operations have been initiated or if previously established WLAN operations have ceased.

3. The method according to claim 2, wherein said repeated steps are performed at a predetermined interval.

4. The method according to claim 1, wherein said step of initiating WLAN operations in the secondary frequency band comprises outputting a communication message from a primary transceiver at the primary frequency to a secondary transceiver that converts the primary frequency to the secondary frequency and then broadcasts the communication.

5. The method according to claim 4, wherein the primary transceiver performs all fine gain and frequency adjustments for the broadcast secondary frequency communication.

6. The method according to claim 1, wherein said step of initiating WLAN operations in the secondary frequency band comprises the steps of:

receiving a communication message at the secondary frequency band;

converting the secondary frequency band communication message to the primary frequency band; and

processing the converted communication message in the primary transceiver.

7. The method according to claim 6, further comprising the step of directing flow of the received and converted received communication via switching that is utilized to properly size the incoming communication so as not to saturate any components of the primary transceiver.

8. The method according to claim 7, wherein said switching comprises at least one switch set to a position not directly connecting a signal path of the incoming communication so that leakage onto the signal path provides an attenuated signal to the signal path.

9. The method according to claim 1, wherein:

said method is embodied in a set of computer instructions stored on a computer readable media;

said computer instructions, when loaded into a computer, cause the computer to perform the steps of said method.

10. The method according to claim 9, wherein said computer instructions are compiled computer instructions stored as an executable program on said computer readable media.

11. The method according to claim 1, wherein said method is embodied in a set of instructions stored in a machine-readable medium.

12. An RF front end, comprising:

a set of at least two antenna ports;

at least two power amplifiers, each power amplifier configured to feed amplified signals to at least one of the antenna ports; and

an input line shared by inputs of each of the at least two power amplifiers.

13. An RF device, comprising:

at least two antenna ports;

an RF front end having at least two power amplifiers (PAs), each PA having an output coupled to one of the antenna ports;

an RF signal generating device; and

an antenna diversity switch coupled to the RF signal generating device and the RF front end, wherein said antenna diversity switch is configured to direct RF signals generated by the RF signal generating device to one of the PAs.

14. The RF device according to claim 13, further comprising at least two antennas, each antenna coupled to one of the antenna ports.

15. The RF device according to claim 14, wherein:

at least one of the antennas is a dual band antenna optimized for use in combined IEEE 802.11a and 802.11b wireless communications.

16. The RF device according to claim 13, further comprising:

at least two transmit/receive switches; and

at least two low noise amplifiers (LNAs), wherein each LNA is paired with one of the PAs and one transmit/receive switch is coupled between each PA/LNA pair and the antenna coupled to the PA, each transmit/receive switch directing signals from the antenna to the LNA, or directing signals from the PA to the antenna.

17. An RF device, comprising:

at least two antenna ports;

an RF front end having at least two LNAs, each LNA having an input coupled to one of the antenna ports;

an RF signal receiving device; and

an antenna diversity switch coupled to the RF signal receiving device and the RF front end,

wherein the antenna diversity switch is configured to direct RF signals from the one of the LNAs to the RF signal receiving device.

18. The RF device according to claim 17, further comprising at least two antennas, each antenna coupled to one of the antenna ports, wherein at least one of the antennas is a dual band antenna optimized for use in combined IEEE 802.11a and 802.11b wireless communications.