SYSTEM AND METHOD FOR MODULARIZING THE FUNCTIONALITY OF AN ELECTRONIC DEVICE

Abstract: A system for modularizing the functionality of an electronic device (10). The system includes a first mechanism for separating different functional blocks of the electronic device into spatially separable hardware modules (12, 14, 16). A second mechanism interfaces the hardware modules via spatially reconfigurable communications links (38, 40). In a specific embodiment, the spatially reconfigurable communications links are infrared links or optical links. The system of the present invention provides for the construction of an integrated (10) device that includes a wireless transceiver (34) and a first circuit (16) that provides a user-interface to receive input signals and to provide output signals. A second circuit (18) processes the input signals and delivers the output signals to the first circuit. A third circuit establishes local wireless communications between the first circuit and the second circuit. In the illustrative embodiment, the first circuit (16) receives voice-input signals and the second circuit processes the voice-input signals. The first circuit includes a speaker that outputs voice signals and a fourth circuit (14) that provides an optical user-interface. The third circuit establishes local wireless communications between the first, second, third, and/or fourth circuits. The second circuit (12) includes a mechanism for providing call processing (34) and diagnostic services (28). The third circuit includes a point-to-point local transport system such as BlueTooth.

Description: SYSTEM AND METHOD FOR MODULARIZING THE FUNCTIONALITY OF AN ELECTRONIC DEVICE BACKGROUND OF THE INVENTION Field of Invention: This invention relates to wireless communications systems. Specifically, the present invention relates to devices such as wireless phones having separable functional components. Description of the Related Art: Portable electronic devices are employed in a variety of demanding applications including wireless communications via laptop and palmtop computers and wireless phones. Such applications require user-friendly devices that provide flexible features to the user. Different users often employ the devices for different applications. For example, a user employing a laptop computer having a radio card and antenna may receive stock market quotes from quoting service. A different user may access the Internet via an Internet service provider. As a result, the devices must provide flexible functionality. Conventionally, some flexible functionality is provided via software installable on a computer within the device. For example, a laptop computer may run software ranging from image editing to accounting software. A wireless phone may include specialized address book and phonebook software. Although the ability of such devices to run various software programs provides improved flexibility and functionality, unfortunately, such devices often lack flexible hardware functionality. Hardware functionality such as wireless data reception and user- interface features is typically implemented in permanently fixed hardware or circuitry and results in relatively inflexible hardware configurations. The hardware is typically not easily changed or adjusted to meet the needs of different applications. The lack of hardware flexibility often results in inefficient devices. For example, a laptop computer having a radio card and an antenna may be used to communicate with the Internet. However, the antenna is typically in close proximity to the computer, which results in significant interference between signals transmitted by the antenna and digital signals and noise generated within the computer. Such interference reduces system performance. The fixed radio card and antenna limits the ability of the user to adjust the antenna to reduce the interference by employing a different hardware setup or by separating the antenna from the computer. In automobile applications, wireless phones may be difficult to read, as the driver of the automobile must keep his or her eyes on the road. Lack of hardware flexibility limits the ability of the user to change user-interfaces of the phone to, for example, a heads-up display included in the automobile. Hence, a need exists in the art for a system and method for providing improved functionality to portable electronic devices. There is a further need for a system that provides for improved user-interface and wireless communications hardware flexibility. SUMMARY OF THE INVENTION The need in the art is addressed by the system for modularizing the functionality of an electronic device of the present invention. In the illustrative embodiment, the inventive system is adapted for use with wireless phones and includes a first mechanism for separating different functional blocks of the comrnunications device into spatially separable hardware modules. A second mechanism interfaces the hardware modules via spatially re-configurable communications links. In a specific embodiment, the spatially re-configurable communications links are infrared links or optical links. The system of the present invention provides for the construction of an integrated device having a first circuit for providing a user-interface to receive input signals. The first circuit also provides output signals via the user- interface. A second circuit processes the input signals and delivers the output signals to the first circuit. A third circuit establishes local wireless communications between the first circuit and the second circuit. A wireless transceiver that is connected to the second circuit facilities the transfer of input and output signals over the air to and from a wireless communications system that provides various wireless services. In the illustrative embodiment, the first circuit receives voice-input signals and the second circuit processes the voice-input signals. The first circuit includes a speaker for outputting voice signals and includes a fourth circuit for providing an optical user-interface, which is an automotive heads-up display. The third circuit establishes local wireless communications between the first, second, third, and /or fourth circuits. The second circuit includes mechanism for providing call processing and diagnostic services. The third circuit includes a point-to-point local transport system such as BlueTooth. The novel design of the present invention is facilitated by the second mechanism implemented in the third circuit that interfaces various device hardware modules via spatially re-configurable communications links. This facilitates the modularization of the hardware functionality of electronic devices, which greatly increases the flexibility of such devices. This improves interchangeability between various functional blocks of electronic communications devices and may enhance manufacturing flexibility, as customers may order various compatible functional modules from different manufacturers and combine them in one wirelessly integrated device. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of a portable electronic communications device of the present invention. FIG. 2 is a more detailed block diagram of the interface between modules of the portable electronic communications device of FIG. 1. FIG. 3 is a diagram of a second embodiment of a portable electronic communications device of the present invention employing a wireless interface to a wireless phone. FIG. 4 is a more detailed diagram of the fiber optic interface between the wireless phone and the external IR/optical transceiver of the device of FIG. 3. FIG. 5 is a diagram of a third embodiment of a portable electronic communications device of the present invention employing a separable modularized acoustics section. FIG. 6 is a more detailed diagram showing requisite interfacing circuitry employed by the portable electronic communications device of FIG. 4. DESCRIPTION OF THE INVENTION While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility. FIG. 1 is a block diagram of a first embodiment of a portable electronic communications device 10 of the present invention. For clarity, various components such as amplifiers, filters, automatic gain control circuitry, mixers, and other circuitry are omitted from FIG. 1. However those ordinarily skilled in the art will know where and how to implement the requisite additional components without undue experimentation or departure from the scope of the present teachings. The device 10 includes a wireless phone 12 having a remote user interface 14 and a remote audio interface 16. The wireless phone 12 includes a local phone infrared (IR) module 18 that is connected to a phone computer 20. The phone computer 20 is connected to a Code Division Multiple Access (CDMA) transceiver 34 for placing wireless phone calls via a wireless CDMA communications system and associated service provider (not shown). The computer 20 runs software for providing various functions including data transfer and over the air (OTA) services 22, call manager services (24), voice encoding and decoding services 26, and diagnostic services 28. The diagnostic services 28 include software for placing Markov calls via the wireless phone 12 and performing other phone and communications system tests. The call manager services 24 include address and phonebook software. The data transfer and OTA services 22 include Internet access software such as browsers and dial-up software. The various services 22, 24, 26, and 28 may be easily implemented in software by one ordinarily skilled in the art. The remote user interface 14 includes a local IR module 30. The remote user interface 14 is implemented as a heads-up automotive display in the present specific embodiment. The remote audio interface 16 includes a local audio IR module 32. The remote audio interface 16 includes a microphone and a car stereo in the present specific embodiment. The wireless phone 12 may be adapted from existing wireless phones via the addition of the local phone IR module 18 and appropriate IR interfacing software running on the computer 20, the interfacing software of which is application-specific and may be designed and developed by one skilled in the art to meet the needs of a given application. Those skilled in the art will appreciate that the CDMA transceiver 12 may be replaced with another type of transceiver such as an analog Advanced Mobile Phone System (AMPS) transceiver without departing from the scope of the present invention. In operation, the phone computer 20 runs software for implementing the data and OTA services 22, the call manager services 24, the voice encoding and decoding services 26, and the diagnostic services 28. Those skilled in the art will appreciate that some of the services 22, 24, 26, and 28 may be omitted, replaced by other services, or other services may be added without departing from the scope of the present invention. The phone computer 20 may run an operating system such as Windows CE @ to facilitate software management. The software running on the phone computer 20 employs the CDMA transceiver 34 and associated antenna 36 to communicate via a wireless service provider (not shown) to provide the data and OTA services 22 to a user of the device 10. An external computer (not shown) may be plugged in to the wireless phone 12 via a data interface adapter (not shown) to facilitate phone diagnostic testing. The requisite software routines running on the phone computer 20 and the internal hardware of the CDMA transceiver 34 to implement the services 22, 24, 26, and 28 via conventional user interfaces and audio interfaces (not shown) are known in the art. The device 10 of the present invention employs additional software to implement the services 22, 24, 26, and 28 via the remote user interface 14 and the remote audio interface 16 of the present invention. The additional software runs on the phone computer 20 and facilitates data flow between the interfaces 14 and 16 via the local IR modules 18, 30, and 32. Each IR module 18, 30, and 32 includes, as discussed more fully below, IR transceivers and drivers to facilitate data transfer over a first IR link 38 between the local phone IR module 18 and the local interface IR module 30 and over a second IR link 40 between the local phone IR module 18 and the local audio IR module 32. A user may employ the device 10 for heads-up display of incoming and /or outgoing call information, for automatic wireless access to automotive mapping services through the phone 12 and so on. Access is provided between the phone 12 and one or more additional devices such as the devices 14 and 16 via the local wireless channel represented by the links 38 and 40. Data links other than infrared may be employed to transfer data between the wireless phone 12 and the user interfaces 14 and 16, such as optical fiber links or other types of radio frequency links without departing from the scope of the present invention. When a user of the wireless phone 12 enters an automobile equipped with user interfaces 14 and 16 and activates the phone 12, the phone 12 employs the automotive heads-up display 14 as the screen of the phone 12 and employs the car stereo and microphone 16 as the phone speaker and microphone. The heads-up display 14 may display information related to phone calls placed via the wireless phone 12 or to other software running on the phone computer 20. Use of the automotive heads-up display 14 helps the user keep their eye on the road as they use the device 10. The automotive heads-up display 14 is also a larger and more readable display than conventional fixed phone displays. The portable electronic communications device 10 may be adapted from a conventional wireless phone by adding the local phone IR module 18, adding additional interfacing software to the phone computer 20, and installing the local IR modules 30 and 32 on the automotive heads-up display 14 and the car stereo and microphone 16. The user interfaces 14 and 16 may require additional application-specific hardware or software to effectively employ the IR links 38 and 40 for inter-device communications. The links 38 and 40 may be implemented via a local point-to-point transport system such as BlueTooth. The teachings of the present invention allow for the development of a variety of small wireless modems, handsets, or similar devices capable of being linked to other remote devices via a local point-to-point radio frequency (RF) link. Such a device, which may be implemented as a small modem, PCMCIA, CompactFlash card, and so on, may be capable of interfacing directly with one or more remotely connected devices that may provide alternate user interface services to the device. The teachings of the present invention allow for the development of very small wireless phones having traditional input /output elements such as keypads, screens, speakers, and microphones to be made available as devices connected by a local point-to-point RF link. FIG. 2 is a more detailed block diagram of the interface 40 between modules 16 and 12 of the portable electronic communications device 10 of FIG. 1. The remote audio interface device 16 includes a car stereo 50 and a microphone 52, both of which are connected to a microchip 54 that runs IR interfacing software. The microchip 54 is connected to the local IR module 30. The local IR module 30 includes an IR driver 56 that is connected to the microchip 54. The IR driver 56 is also connected to an IR transceiver 58 that transmits and receives IR signals over the data link 40 to an IR transceiver 60 included in the local phone IR module 32 of the wireless phone 12. The phone IR module 32 also includes a phone IR driver 62 that is connected to the phone computer 20, which runs additional interfacing software similar to the software running on the microchip 54 of the remote audio interface device 16. In operation, user audio interface functionality required by software running on the phone computer 20 or other phone hardware is implemented via the remote audio interface device 16. For example, during a phone conversation, a user inputs voice data via the microphone 52, which is fed to the microchip 54 in preparation for transmission over the wireless IR link 40 to the wireless phone 12. The wireless phone 12 receives the voice data via the local phone IR module 32 and subsequently process the voice data via the phone computer 20 and/or other hardware (not shown) in preparation for wireless transmission via the CDMA transceiver 34 and antenna 36 of FIG. 1. Similarly, the antenna 36 and the transceiver 34 of FIG. 1 may receive voice data from another party, which is processed via the phone computer 20 and/or other hardware (not shown) in preparation for transmission over the IR link 40 via the local phone IR module 32. The local audio IR module 30 in the remote audio interface device 16 receives the voice data and transfers it to the microchip 54 where it processed in preparation for acoustic output via the stereo speaker 50. The IR interfacing software running on the microchip 54 facilitates use of the microphone 52 and the stereo 50 as input and output devices, respectively by the wireless phone 12 via the IR link 40. Use of the IR modules 30 and 32 and accompanying interfacing software running on the microchip 54 and the phone computer 20 allows different functional blocks of a wireless phone 12, such as the user interface 16, to be spatially separable. This improves hardware functionality by increasing the ability of the user to maneuver the modules 14 and 16 of FIG. 1 and easily interchange them with other modules (not shown) that are adapted for use with the present invention via the addition of IR modules and appropriate interfacing software. FIG. 3 is a diagram of a second embodiment of a portable electronic communications device 70 of the present invention employing a wireless link 74 to an external IR/optical transceiver 76. The external IR/optical transceiver 76 is connected to a wireless phone 78 via a fiber optic cable 80. The laptop computer 72 includes a laptop IR transceiver and interface card 82, the construction of which is known in the art, for transferring IR signals between the laptop computer 72 and the external IR/optical transceiver 76 over the wireless link 74. The external IR/optical transceiver 76 optically transmits signals received from the laptop computer 72 via the wireless link 74 to the wireless phone 78. The wireless phone 78 includes an optical interface adapter as discussed more fully below to facilitate communication between the laptop computer 72 via the external IR/optical transceiver 76. Software running on the laptop computer 72 employs the wireless phone 78 as a wireless modem via the wireless link 74, the external IR/optical transceiver 76, and the fiber optic cable 80 and associated interfaces. The requisite software may be easily constructed by one skilled in the art. The various interface components 82, 76, and 80 allow the wireless phone 78 to be operated at a distance from the computer 72, which is a source of undesirable noise that occupies the frequency band employed by the wireless phone 78, to receive and transmit wireless signals. As a result, undesirable interference is limited and the performance of the wireless phone 78 is enhanced. The external IR/optical transceiver 76 provides improved hardware flexibility. The advent of digital phones has made possible the use of computers with wireless phones to allow a computer remote access to standard services available via a phone line. The present invention facilitates the use of wireless data links that may be used separate the wireless phone and the computer. This provides a distinct advantage in that the phone and accompanying transceiver may be positioned away from the computer. This reduces computer-generated interference with transceiver signals. The teachings of the present invention may be extended to modularize the phone into functional blocks grouped in accordance with a use model for the phone. For example, in an implementation of the present invention that is discussed more fully below, a wireless phone maintains a wireless interface between a phone transceiver and accompanying acoustic devices. The transceiver may be attached to the user's belt or other nearby objects such as purse straps, glasses (as discussed more fully below), a pen, or other devices. The user is then freed from some of the cumbersome aspects of wireless phone use. The device 70 of FIG. 3 provides another example, where modularized functional blocks include the semi-stationary IR/optical transceiver 76 that communicates with remotely connected devices such as the laptop computer 72, via the wireless link 74. The teachings of the present invention may also be employed to develop devices having functional blocks grouped in accordance with power requirements such as a grouped battery and transmitting antenna. A receiver and accompanying antenna, with lower power requirements may then be positioned elsewhere. This may lead to the development of remote power sources. FIG. 4 is a more detailed diagram of the fiber optic interface between the wireless phone 78 and the external IR/optical transceiver 76 of the device of FIG. 3. The interface includes, from left to right, an IR transceiver 90 and accompanying IR drivers (not shown), a transceiver fiber optic data interface adapter 92, the fiber optic cable 80, the phone wireless data interface adapter 94, and the cellular telephone 78. The transceiver fiber optic data interface adapter 92 includes, from left to right, an RS-232 to transistor-transistor logic (TTL) driver 96 that includes a TTL to RS-232 driver (not shown). The transistor- transistor logic (TTL) driver 96 is connected in parallel to a first photodetector 98 and a first optical transmitter 100. The fiber optic cable 80 connects the first photodetector 98 to a second transmitter 102 and connects the first transmitter 100 to a second photodetector 104, which are both located in the optical data interface adapter 94. The second transmitter 102 and the photodetector 104 are connected to the cellular telephone 78 via standard connection systems. In the present specific embodiment, the fiber optic cable 80 is duplex plastic fiber optical cable. The interface between the RS-232 to TTL driver 96 and the interface between the RS-232 to TTL driver 96 and the first photodetector 98 and the first optical transmitter 100 are standard interfaces known in the art. The RS-232 to TTL driver 96 is made by Analog Devices Inc., part number ADM202EARW, Dual RS-232 Driver /Receiver. The photodetectors 98 and 104 are Siemens SFH551/1-V-1 plastic fiber optic integrated photodetectors. The transmitters 100 and 102 are Siemens SFH796V plastic fiber optic transmitter diodes. The duplex fiber optic cable 80 is Mitsubishi EHV4002 1000 micron 2 plastic fiber optic cable. In operation, TTL data to be directed from the IR tiansceiver 90 to the cellular telephone 78 is transferred to the RS-232 to TTL driver 96, which is a standard serial bus driver. The TTL data is formatted for RS-232 serial transmission and is transferred to the first transmitter 100. The first transmitter 100 converts the electrical serial data to serial optical data that is transmitted via the fiber optic cable 80 to the second photodetector 104, where it is converted back to electrical signals and subsequently transferred to the cellular telephone 78. The cellular telephone 78 then processes the electrical serial data via circuits such as a baseband processor (not shown) on a baseband chip (not shown). Similarly, serial data to be transferred from the cellular telephone 78 to the IR transceiver 90 is directed to the second optical transmitter 102, where it is converted to optical serial data and tiansmitted via the fiber optic cable 80 to the first photodetector 98 where it is detected and converted to electrical serial data. The electrical serial data is transferred to the RS-232 to TTL driver 96 where it is converted to TTL format. The TTL data is then transferred to the IR transceiver 90 for further processing. The RS-232 to TTL driver 96 may be replaced with another type of driver without departing from the scope of the present invention. Also, the position of the RS-232 to TTL driver 96 may be switched to the cellular telephone optical data interface adapter 94. In addition, other additional drivers may be included in the interface adapters 92 and 94 and /or within the IR transceiver 90 or cellular telephone 78 without departing from the scope of the present invention. FIG. 5 is a diagram of a third embodiment of a portable electronic communications device 110 of the present invention employing a separable modularized acoustics section 112 on a pair of glasses 114. The acoustics section 112 includes a microphone 116 and a speaker 118 connected to an acoustic interface attachment implemented as a small chip as discussed more fully below. A special wireless phone 120 includes an IR adapter 122. In operation, the wireless phone 120 employs the acoustics section 112 on the glasses 114 to provide acoustic user-interface functions. The microphone 116 and the speaker 118 replace conventional spatially fixed microphones and speakers (not shown). Requisite information and control signals are transferred between the acoustics section 112 and the wireless phone 120 via wireless infrared electromagnetic energy. FIG. 6 is a more detailed diagram showing requisite interfacing circuitry 130 employed by the portable electronic communications device 110 of FIG. 4. The acoustics section 112 is implemented on an eyeglass attachment that contains the microphone 116 and speaker 118 connected to a communications circuit 132. The communications circuit 132 is connected to a first IR adapter 134 at a first IR interface card 136. The first IR interface card 136 is connected to a first IR tiansceiver 138. The first IR transceiver 138 is connected to a second IR transceiver 140 in the second IR adapter 132 in the wireless phone 120 via the IR link 74. The second IR adapter is connected to the phone computer 20, which communicates with an additional user interface 144 and the CDMA transceiver 34. In operation, acoustics information is input to the communications circuit 132 via the microphone 116. The acoustics information is subsequently transferred to the phone computer 20 via the IR adapters 134 and 122, where it is either processed as a software voice command or is processed in preparation for transmission to an outside party via the CDMA transceiver 34 and antenna 36. Similarly, the computer 20 processes voice or other acoustic signals that are received by the CDMA transceiver 34. Subsequently, the acoustic signals may be transferred to the speaker 114 to output voice or other acoustic information. The construction of communications circuits, such as the communications circuit 132 and the IR adapters 134 and 122 are known in the art. Thus, the present invention has been described herein with reference to a particular embodiment for a particular application. Those having ordinary skill in the art and access to the present teachings will recognize additional modifications, applications and embodiments within the scope thereof. It is therefore intended by the appended claims to cover any and all such applications, modifications and embodiments within the scope of the present invention. Accordingly, WHAT IS CLAIMED IS:

Claims: CLAIMS 1. A system for modularizing the functionality of an electronic device comprising: first means for separating different functional blocks of said communications device into spatially separable hardware modules and second means for interfacing said hardware modules via spatially re- configurable communications links. 2. The system of Claim 1 wherein said spatially re-configurable communications links are infrared links. 3. The system of Claim 1 wherein said spatially re-configurable communications links are optical links. 4. The system of Claim 3 wherein said optical links are implemented via fiber optic cable. 5. An integrated device comprising: means for providing a user-interface to receive input signals and provide output signals; means for processing said input signals and delivering said output signals to said means for providing; and means for establishing local wireless communications between said means for providing and said means for processing. 6. The device of Claim 5 further including a wireless transceiver in communication with said means for processing. 7. The device of Claim 6 wherein said means for providing a user interface includes first means for receiving voice input signals. 8. The device of Claim 7 wherein said means for processing includes second means for processing said voice input signals. 9. The device of Claim 8 wherein said means for providing includes third means for outputting voice signals. 10. The device of Claim 9 wherein said means for providing further includes fourth means for providing an optical user-interface. 11. The device of Claim 10 wherein said optical user-interface is an automotive heads-up display. 12. The device of Claim 11 wherein said means for establishing local wireless communications between said first, second, third, and /or fourth means. 13. The device of Claim 12 wherein said means for processing includes means for providing call processing services. 14. The device of Claim 13 wherein said means for processing includes means for providing further including means for providing diagnostic services. 15. The device of Claim 14 wherein said means for providing call processing services and said means for providing diagnostic services includes software running on said means for processing. 16. The device of Claim 5 wherein said means for establishing local wireless communications includes a point-to-point local transport system. 17. The device of Claim 16 wherein said point-to-point local transport system is BlueTooth. 18. The device of Claim 16 wherein said local wireless communications is radio frequency communications. 19. An integrated device comprising: a wireless modem; a local point-to-point radio frequency transport system; and one or more user-interface, diagnostic, or audio interface devices interfaced via said local point-to-point radio frequency transport system, said devices for utilizing wireless services provided via said wireless modem and a service provider. 20. An interface for different functional blocks of a portable electronic device comprising: first means for receiving and transmitting a signal; second means for receiving and transmitting said signal between said first means and said second means over a wireless or optical link; third means for providing a first function of said portable electronic device; fourth means for providing a second function of said portable electronic device; and fifth means for interfacing said first means to said third means and said second means to said fourth means to facilitate communication between said third means and said fourth means. 21. A modular portable electronic device comprising: a first hardware module for performing a first function; a second hardware module for performing a second function adapted for use with said first function; a first transceiver in electrical communication with said first hardware module for tiansmitting and receiving a first signal of a first predetermined frequency and for transferring a second signal based on said first signal between said first hardware module; and a second transceiver in electrical communication with said second hardware module for transmitting and receiving said first signal of a first predetermined frequency between said first transceiver and said second transceiver over a wireless or optical interface and for transferring a third signal based on said first signal between said second transceiver and said second hardware module. 22. The device of Claim 21 wherein said first predetermined frequency is an infrared frequency. 23. The device of Claim 21 wherein said first hardware module is a laptop computer. 24. The device of Claim 23 wherein said second hardware module is a wireless phone. 25. The device of Claim 23 wherein said second hardware module includes an antenna and a radio card for facilitating wireless communications by said first hardware module. 26. The device of Claim 21 wherein said first hardware module includes a computer. 27. The device of Claim 26 wherein said second hardware module includes a user interface. 28. A method for modularizing the functionality of an electronic device comprising the steps of: separating different functional blocks of said communications device into spatially separable hardware modules and interfacing said hardware modules via spatially re-configurable communications links.

Inventors: DRAXLER PAUL J, SPRIGG STEPHEN A, WALLACE RAYMOND C, DRAXLER, PAUL, J., SPRIGG, STEPHEN, A., WALLACE, RAYMOND, C.
Applicants: QUALCOMM INC, QUALCOMM INCORPORATED
Application year: 2001
Main classification: H04B5
IPC codes: H04B1, H04B10, H04M1, H04Q7