Systems and methods are disclosed for short range wireless communications of voice and/or data using signals within the FM frequency band to form an FM band communication link between two or more systems. The disclosed systems and methods provide lower cost and lower power solutions than are provided by existing wireless offerings using technology such as Bluetooth.
In operation, the remote system 104 receives voice or data input 105, such as through a microphone that picks up a user's speech and/or through other user input. The remote system 104 then processes the voice and/or data input and uses the FM band TX/RX integrated circuit 100 to transmit voice and/or data content to base system 102 through FM band transmissions 106, thereby providing a short range wireless communication link. The base system 102 receives the FM band transmissions with the FM band TX/RX integrated circuit 100 and processes the voice and/or data content. In turn, the base system 102 can receive voice and/or data input 103, such as through a communication network transmission, such as a cellular network transmission. The base system 102 then processes the voice input and uses the FM band TX/RX integrated circuit 100 to transmit voice and/or data content to remote system 104 through FM band transmissions 108 thereby providing a short range wireless communication link. The remote system 104 receives the FM band transmissions with the FM band TX/RX integrated circuit 100 and processes the voice and/or data content. It is noted that the FM band signals used to form the FM band communication link can be modulated and coded as desired to achieve the operational objectives desired. For example, the signals can be encoded to reduce the likelihood of interception. Any modulation and/or encoding placed on the transmitted FM band signals would then be demodulated and/or decoded upon reception.
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In a vehicle implementation, for example, the voice pick-up device could be located at any desired position in the vehicle, such as a position in good proximity to the driver of the vehicle. One such location, for example, could be the visor in front of the driver. The base system could be a navigation, entertainment and/or control system for the vehicle. In addition, the base system could be a communication system that further transmits the voice and/or data content. If desired, for example, the base system could further transmit voice/data content through FM band communications to the vehicle radio and/or entertainment systems. In this case, the base system could have an FM band TX/RX integrated circuit 100 and use the TX circuitry to send the voice/data to the vehicle systems. The vehicle systems could include an FM band RX integrated circuit 110 for receiving the FM band communication. If desired, the vehicle system could also be configured to output the voice content from the FM band transmissions through the speaker system of the vehicle. This use of the vehicle speakers could be useful, for example, where the base system is a cellular telephone handset. Still further, to improve performance, it is noted that adaptive echo cancellation could be utilized with respect to the microphones discussed herein in order to improve voice pick-up.
In operation, the headset 104 receives voice and/or data input 105, such as through a microphone that picks up a user's speech or broadcast data received by the headset. The headset 104 then processes the voice input and uses the FM band TX/RX integrated circuit 100 to transmit voice and/or data content to handset 102 through FM band transmissions 106 thereby providing a short range wireless communication link. The handset 102 receives the FM band transmissions with the FM band TX/RX integrated circuit 100 and processes the voice and/or data content. In turn, the base system 102 can receive voice input from the cellular network through antenna 204. The handset 102 then processes the voice input and uses the FM band TX/RX integrated circuit 100 to transmit voice and/or data content to headset 104 through FM band transmissions 108 thereby providing a short range wireless communication link. The handset 104 receives the FM band transmissions with the FM band TX/RX integrated circuit 100, processes the voice data, and provides an output to the user through speaker 206.
It is noted that the FM band frequency transmissions can be modulated and coded as desired to achieve the operational objectives desired. As examples, such modulations as frequency modulation (FM), Gaussian minimum shift keying (GMSK), frequency shift keying (FSK), etc. may be used, as just a few examples. As depicted, the FM band transmissions 106 and 108 can make up a wireless voice/data link 202 between the handset 102 and the headset 104. If desired, this data link 202 can be digitally modulated. In addition, this data link 202 can be encrypted, if desired, to reduce the possibility of a third party intercepting the transmissions.
In general, therefore, an FM band transceiver is included in a first device (e.g., the handset), and an FM band transceiver is included in a second device (e.g., the headset) so that an FM band wireless communication bi-directional or unidirectional link can be established for short range communications. If desired, an integrated antenna, such as a loop or short stub, can be used on both devices, for example, if there were no headphone cable that could be utilized. Duplex communications can be provided using time division duplexing (TDD) and/or frequency division duplexing (FDD) to avoid interference and/or reduce current consumption. With respect to TDD, some digital modulation, such as GMSK, could be used to save power consumption and also to achieve some level of security to prevent eavesdropping. Analog FM modulation could be used with FDD. However, with respect to FDD, a hybrid circuit could be used to separate the RX signal from the TX signal (˜1 Vrms). While it would be desirable to use a single local oscillator (LO) within the FM band TX/RX integrated circuit 100 for both transmit and receive operations, a different intermediate frequency (IF) could be used for the transmit and receive operations in a low-IF architecture.
With respect to the handset, a digital audio interface could be utilized similar to a Bluetooth (BT) chip, such as a PCM interface or an 12S interface. Analog to digital converters (ADCs) within the FM band TX/RX integrated circuit 100 for the handset can be used for receive operations, and digital to analog converters (DACs) within the FM band TX/RX integrated circuit 100 for the handset would be used for transmit operations.
With respect to the headset, communications with a microphone and earphone speaker could be accomplished using a microphone amplifier and a headphone driver. In addition, battery management features could also be provided for the headset, and integrated with the FM band TX/RX integrated circuit in some instantiations. The additional circuitry could also be provided in addition to the FM band TX/RX integrated circuit 100, if desired, to facilitate the operation of the headset (or the handset). If the additional circuitry were included in an integrated circuit, this IC could be combined with the FM band TX/RX integrated circuit 100 into an MCM (multi-chip module), if desired.
As described here, therefore, an FM transmitter and FM receiver are used to create a voice and/or data connection between two devices to pass wireless voice and/or data back and forth between the two devices. The described solutions provides a replacement for traditional “wired” and Bluetooth (BT) wireless connections, such as are found with respect to headsets for many cell phones, portable media players, portable audio devices, or other portable devices. Each device has a FM transceiver, or both an FM receiver and an FM transmitter. In other words, for bi-directional communications, each device has the ability to both transmit and receive content in the FM band through the FM communication link. It is further noted that a device can only have an FM transmitter or an FM receiver, for example, if a unidirectional implementation is desired.
While the signal for the wireless communication links discussed here will typically be in the FM frequency band, it can be modulated and encoded, as desired, for the wireless short range communication link between the base system and the remote system discussed above. It is noted that within the United States, FM audio broadcast signals are broadcast in 200 KHz channels in the frequency band from 88 MHz to 108 MHz. European FM stations fall within a similar frequency range with 100 KHz channels. Japanese FM stations are from 71 to 91 MHz.
The FM band TX/RX integrated circuit 100 can be configured to provide audio broadcast reception within a frequency band, such as the FM band, and to provide wireless voice/data communications on a modulated signal having a frequency within the same frequency band. The signal modulation for this wireless voice/data signal, however, need not be standard FM modulation as used for audio broadcasts. The operational control of the FM band TX/RX integrated circuit 100 can be provide, for example, through software control, if desired.
Device applications for these disclosed embodiments include, but are not limited to, cellular handset plus wireless headset applications, portable media player plus wireless headset applications, portable audio player plus wireless headset applications, portable gaming devices plus wireless headset applications, portable data management devices plus wireless headset applications, push-to-talk or walkie-talkie plus wireless headset applications, portable CD players plus wireless headset applications, or consumer electronics plus wireless headset applications. Other embodiments and applications could also be implemented if desired.
If desired, one device can be the master device, and one device can be the slave device. The master can be configured to dictate when the slave transmits and receives. The master can also dictate the security mechanism and process. Further, the master can dictate the transmit and receiver frequencies within the FM band.
With respect to security, an association mechanism can be utilized. For example, the two devices can be re associated to one another using an automatically generated, manufacturer loaded, or user-generated code. The two devices can associate and remain so unless completely powered down with no reserve battery power. In the case of the devices becoming unassociated due to complete power down, the association can be reset to a factory-installed setting and then be ready for reset. The association security mechanism is for association of the two devices.
To connect, the two devices can be programmed to follow a particular handshake, recognition or configuration routine. For example, the master device could scan the FM band for low power FM broadcast signals, and then select an FM frequency based on predetermined criteria and send the target frequency for the data connection to the slave device. The slave device could then tune to the target frequency and data exchange could begin.
As discussed above, digital modulation can be used for the wireless communication link. For example, digital modulation can be used to carry the data. GFSK, GMSK, or OFDM in conjunction with TDD (time domain division) frequency management can be used to further increase security and quality of voice and/or data transferred.
Further, if desired, data communications between the two FM transceivers can be encrypted using a simple overlay to the modulation. The two devices can share an encryption key that is refreshed with each new connection, or maintained from initial synchronization.
With respect to antennas, the devices could use an integrated tuned antenna, such as a loop or short stub. Each device would therefore use its FM transceiver to tune the antenna to the desired frequency.
FM interference can be managed by monitoring the receive channel for FM modulated signals. FM modulated signals will be different than the data connection between the two FM transceivers. However, if an FM modulated signal is received above a pre-determined SNR threshold, the master FM receiver can scan the FM band for received power levels and dictate a new tuned frequency to the slave FM receiver, which will tune to the new frequency. Other implementations can also be used to monitor and reduce interference, if desired.
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
This application claims the benefit under 35 U.S.C. §119(e) to U.S. Provisional Application Ser. No. 60/853,082, entitled, “SHORT RANGE WIRELESS COMMUNICATIONS USING FM BAND COMMUNICATION LINKS AND RELATED SYSTEMS,” which was filed on ______, and is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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60853082 | Oct 2006 | US |