Abstract:
A system for repeating radio signals to the outside of a structure, from transmitters operating within a structure that normally prevents radio transmissions from propagating out of the structure. A system for repeating radio signals to the inside of a structure, from transmitters operating outside a structure that normally prevents radio transmissions from propagating into the structure.

Description:
This application is a divisional of U.S. application Ser. No. 12/000,202, filed on Dec. 10, 2007, which claims priority of U.S. Provisional Application No. 60/873,571 filed on Dec. 8, 2006 under 35 U.S.C. §119(e), the entire contents of which are incorporated by reference herein. 
    
    
     BACKGROUND 
     When used within a structure such as an office building, modern cell phones and portable radios used by the public and by emergency first responders, i.e. police, fire, EMS, etc., have difficulty maintaining communications with base stations and other radios inside and outside of the building. The reason for poor communications in these structures is because they are customarily built with steel frames or reinforced concrete, which impedes the transmission of radio signals into or out of the structure. Poor cell phone performance is a typical complaint. Even more serious, when responding to an emergency in such a structure, this limitation on radio signal transmission has the potential to place the first responders and the occupants of the structure in great jeopardy. 
     The deployment of a system of radio repeaters connected by communications paths within the structure provides the solution to the problem of maintaining radio communications within structures that impede these signals. The repeaters support 2-way radio communication within a structure and between users inside the structure and users and networks outside of the structure. 
     In Building Communications (IBC) can be achieved by converting and coupling/decoupling the standard transmit and receive free space radio signals from radio users within the structure (occupants, first responders, etc.) to communication paths within the structure for distribution throughout the structure. As used in this document, communication path (“Comm Paths”) can include any structure wiring (power mains, telephone wiring, network wiring, alarm wiring, fiber optics, or the like) and/or structural building elements (structural steel, plumbing, standpipes, elevator components, and the like) that support coupling and decoupling of communications signals to a Comm. Paths. As used herein, communication signals include, but are not limited to, radio frequency, acoustic, light, magnetic, or similar signals capable of being converted into intelligible signals. Comm. Path Signals are any communication signals traveling over a Comm. Path. One or more repeaters on the outside of the structure connected to one or more Comm. Paths are used to convert and couple/decouple radio transmissions between radio users inside the structure and radio users and networks outside the structure. An exemplary implementation of IBC would be a Broadband Over Powerlines (BPL) transmission (Comm. Path Signal) over power mains wiring (Comm. Path) in a structure. 
     SUMMARY 
     A system comprising a device for facilitating communication between communication devices, wherein the communication devices are located at different locations in the interior of a structure or at different locations around the exterior of the structure, the device including a receiver for receiving a signal having a first frequency either within the interior of a structure or at the exterior of a structure, converting the received signal to signal having an intermediate frequency. A Communication Path coupler provides for connecting to a portion of a structure, wherein the portion of the structure is a communication path over which the intermediate frequency signals can travel. A transmitter capable of converting intermediate frequency signals back to signals having the first frequency and transmitting the signal having the first frequency to communication devices is located at different locations in the interior of a structure or at different locations around the exterior of the structure. 
     A communication system including a first and second portable communication devices for receiving and transmitting signals having a first frequency. The devices include a receiver capable of receiving a signal having the first frequency either within the interior of a structure or at the exterior of a structure, converting the received signal to signal having an intermediate frequency. A communication path coupler connects to a portion of a structure, wherein the portion of the structure is a communication path over which the intermediate frequency signals can travel. A transmitter converts intermediate frequency signals back to signals having the first frequency and transmitting the signal having the first frequency, wherein the first communication device is located in the interior of the structure and the second device is located on the exterior of the structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         FIG. 1  shows communication signal repeaters within a structure. 
         FIG. 2  shows an exemplary embodiment of a repeater that translates free space radio signals onto Comm. Paths. 
         FIG. 3  shows an exemplary embodiment of a repeater that translates free space radio signals onto Comm. Paths. 
         FIG. 4  shows an exemplary embodiment of a repeater that translates free space radio signals onto Comm. Paths. This repeater uses a duplexer to allow a common antenna for transmitting and receiving signals. 
         FIG. 5  shows an exemplary embodiment of a repeater system. 
         FIG. 6  shows two exemplary embodiments for bypassing impediments to the transmission of radio signals on Comm. Paths. 
         FIG. 7  shows an exemplary embodiments of a repeater that translates free space radio signals onto one or more Comm. Paths. 
         FIG. 8  shows another exemplary embodiment of a unidirectional repeater that translates free space radio signals onto one or more Comm. Paths. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exemplary embodiment, wherein a structure  100 , that impedes radio transmissions, contains a plurality of radio repeaters  101 ,  102 , that are connected to one or more Comm. Paths  105  within the structure  100 . Of course, any number of additional repeaters as required or desired for reliability purposes can be used. A repeater outside of the structure  104  is also connected to one or more Comm. Paths. 
     Transmissions from radios outside of structure  100  are received on repeater  104  and converted to Comm. Path compatible signals that are then coupled into one or more Comm. Paths. All repeaters inside the structure  101  receive the Comm. Path radio signals and convert them back to a free space radio signals that can be detected inside the structure. Conversely, free space radio transmissions from any first responder  110  in the structure are received on a repeater such as  101  and converted to Comm. Path compatible signals that are coupled to one or more Comm. Paths  105 . 
       FIGS. 2 ,  3  and  4  are exemplary embodiments of a carrier current or BPL variant of the present invention. 
     In the repeater  200  of  FIG. 2 , a receiver antenna  201  receives signals from a radio transmitter. This repeater  300  uses separate antennas for transmitting and receiving signals. The received radio signal is connected to a radio receiver  202 , amplified and converted to a lower intermediate frequency. The output of radio receiver is fed to power line coupler  203 . The power line coupler  203  injects the intermediate frequency signal into power line  204 . Similarly, an intermediate frequency signal from power line  204  can be passed to the input of transmitter  206 , for example, a heterodyne transmitter, by means of the power line coupler  205 . The intermediate frequency is up converted and amplified by the transmitter  206 . The transmit radio signal is fed to transmit antenna  207 . 
     In the repeater of  FIG. 3 , this repeater  300  uses a common antenna  306  for transmitting and receiving signals. Relay  302  can be used to determine whether the repeater  300  is in the transmit or receive mode of operation. An antenna  301  receives signals from a radio transmitter  310 . The received radio signal is connected to radio receiver  303  thru relay  302 , amplified and down converted to a lower intermediate frequency. The output of receiver  303 , for example a heterodyne receiver, is fed to power line coupler  304 . The power line coupler injects the intermediate frequency signal into power line  305 . Similarly, an intermediate frequency signal from power line  305  can be passed to the input of radio transmitter  307  by means of the power line coupler  306 . The presence of a minimum transmit signal level causes the COR (carrier operated relay) output of the transmitter to activate relay  302 , connecting the antenna  301 , to the transmitter  310  output. The COR relay can be activated by determining that a radio carrier signal is present or by means of a VOX audio presence detector. The intermediate frequency is up converted and amplified by heterodyne transmitter  307 . 
     In the repeater of  FIG. 4 , an antenna  401  receives signals from a radio transmitter  410 . The received radio signal is passed to receiver  403  thru duplexer  402 , amplified and converted to a lower intermediate frequency. The output of receiver  403  is fed to power line coupler  404 . The power line coupler  404  injects the intermediate frequency signal into power line  405 . Similarly, an intermediate frequency signal from power line  405  can be passed to the input of radio transmitter  407  by means of the power line coupler  406 . The intermediate frequency is up converted and amplified by the radio transmitter  410 . The transmit radio signal is fed to the antenna  401  thru duplexer  402 . 
     In  FIG. 5 , Group A repeaters  502  and  505  can use, for example, intermediate frequency band A, while repeaters  503  and  504  can use, for example, intermediate frequency band B. Although, it does not matter which repeaters repeats which intermediate frequency band. Intermediate frequency bands A and B are sufficiently separated in frequency such that filters in the radio transmitter and radio receiver are able to prevent mutual interference between the repeater elements of group A ( 502  and  505 ) and the repeater elements of group B ( 503  and  504 ). 
     In  FIG. 6 , the Comm. Paths  601 ,  603  and  605 , operate at 3 different voltages. Power transformers  602  and  604  are step down transformers which typically block radio signal transmissions on mains power lines.  FIG. 6  shows, for example, two means of bypassing the power transformers. Of course, other suitable bypass means can be used. 
     In the first case, power line coupler  606  is connected to a high voltage power line  601 . Power line coupler  606  is also connected to an impedance transformer  607 , which is in turn connected to power line coupler  608 , on the low voltage side of transformer  602 , thus creating a path for the radio signals on mains power line  601  to bypass transformer  602  and be coupled onto mains power line  603 . 
     In the second case, repeater  609  is connected to power line mains  603  and repeater  610  is connected to power line mains  605 . These repeaters may use free space radio signals to couple the power line mains signals between power lines mains  603  and  605 , and thus bypass transformer  604 . Alternatively, repeaters  609  and  610  can use other modalities to communicate with each other, such as optical coupling, capacitive coupling, inductive coupling, and the like. 
     In the case of multiphase power line wiring, couplers such as the ones shown in  FIG. 6  would need to be connected for each wiring phase. 
     In the repeater of  FIG. 7 , a receiver antenna  701  receives signals from a radio transmitter  720 . The received radio signal is connected to radio receiver  702 , amplified and converted to a lower intermediate frequency. The output of the radio receiver  702  is fed to an analog-to-digital converter (ADC)  703 , which digitizes the analog input signal at a rate that meets or exceeds the Nyquist sampling criterion. The digital output of the ADC  703  is sent to a digital down converter (DDC)  704  to limit the bandwidth and data rate. The output of the DDC  704  is connected to a packet engine  705 , which takes the raw data and converts it to packets for the purposes of transmission by means of BPL transmitter  706 . The output of the BPL transmitter  706  is coupled to the mains power wiring  708 , by power line coupler  707 . In the other direction, BPL signals on the mains power wiring  708 , are coupled to BPL receiver  710  by power line coupler  709 . The data packets recovered by the BPL receiver are fed to the packet engine for conversion from packets back to raw data. The raw data is sent to a digital up converter (DUC)  711  and from there to a digital-to-analog converter (DAC)  712 . The analog signal output of the DAC  712  is fed to heterodyne transmitter  713 , which converts the signal to a free space radio signal by means of antenna  714 . Analog signals enter the ADC  703  and leaving the DAC  712  must be filtered to prevent aliasing and limiting bandwidth. 
     A microprocessor  715  can receive control commands from a remote device  730 . The control information may be stored in memory  716 . The control information can be used to change various performance characteristics of the repeater  700 , such as center frequency, transmit amplitude, or other characteristics. Similarly, information about the condition of the repeater  700  may be sent to a remote monitoring device  740 . The remote monitoring device  740  can use the information provided to determine reliability schedule maintenance or the like. The repeater  700  can also be controlled locally via keypad  717 . A sensor  718 , connected to the microprocessor, can be monitored remotely to evaluate critical safety parameters such as temperature, and the like. 
       FIG. 8  illustrates an exemplary embodiment of a system comprising a radio receiver  810  or a microphone  811  can be used as a source of an audio signal for amplification by amplifier  809 . The output of the amplifier  809 , the Comm. Path Signal, is sent to a transmit coupler  808 , an audio transducer that is attached to or is formed from an element of the structure that forms Comm. Path  804 . At the receive only (RO) repeater  820 , the Comm. Path Signal is detected by a Comm. Path receive coupler  805 , which can be an audio transducer. The output of coupler  805  is fed to a receive amplifier  806 , and the output of the amplifier  806  drives loudspeaker  807 . Other RO repeaters can be deployed throughout the structure. The audio signal is broadcast on the IBC Comm. Path, consequently all the loudspeakers will emit the same audio signals simultaneously. 
     Another example of connecting to the same IBC Comm. Path is represented by the signal path formed by microphone  815 , radio transmitter  814 , radio receiver  813 , which can have a built-in audio amplifier capable of driving a transmit coupler, and Comm. Path transmit coupler  812 . A suitable microphone, for example, is one that produces an audio output signal with a very high signal-to-noise ratio, such as a bone conduction microphone. The transmitter and receiver could be Bluetooth compliant devices or some similar types of devices having both wired, wireless or both capabilities. 
       FIG. 9  illustrates an exemplary embodiment comprising ultrasonic devices. A free space radio repeater  901  converts free space radio signals received from either a remote transmitter to a building structure or within a building structure, to an intermediate frequency signal. The intermediate frequency signal is fed to an ultrasonic transceiver  902 , which in turn sends its&#39; output, the Comm. Path signal, to a ultrasonic coupler  903 , that is attached to an element of the building structure that forms a Comm. Path  904 , which is coupled to the building structure  904 . The Comm. Path signal is detected on the Comm. Path  904  by ultrasonic coupler  910 . The output of ultrasonic coupler  910  is sent to the input of ultrasonic transceiver  909 . The output of ultrasonic transceiver  909  is connected to the input of radio repeater  908 , which converts the signal to a free space radio signal again. 
     The digital repeater implementation outlined in  FIG. 7  has added costs and benefits. The SDR based repeater is more complicated and expensive to build, however, it&#39;s benefits include digital stability over temperature variations and time, and other benefits, and precise digital control for selection of the repeater center frequency and bandwidth. 
     In  FIGS. 2 ,  3 ,  4  and  7 , the radio receiver and radio transmitter may be configured to share a common power line coupler (e.g., Comm. Path coupler). 
     In another embodiment, a first responder can carry a repeater into a structure, connect the repeater into a Comm. Path outlet (e.g., a power mains outlet), and maintain contact with radios outside of the structure. If batteries are used as a supplementary power source for the repeaters, the repeaters will continue to operate even if the structure&#39;s main power is shut off. When power lines are used as the Comm. Paths in structures that have power transformers to assist with power distribution, a transformer radio signal bypass means can be installed, although it is not necessary. 
     Repeaters may be hardwired to the Comm. Paths where it is economically attractive or where local or national electrical codes mandate such a connection. 
     Repeater systems such as the ones outlined may be applied to many free space radio based services, including cellular telephone service, 802.11 Wi-Fi Ethernet and 802.16 WiMAX Ethernet, and the like. 
     The content of the radio transmissions facilitated by the repeaters may be audio, video or data. 
     Repeaters may, as necessary, demodulate signals, process the demodulated signals, and remodulate signals. 
     As noted previously, structure Comm. Paths other than the main power lines can be used to carry the converted radio signals of repeaters. Some examples of such alternate wiring are telephone system wiring, alarm system wiring, data network wiring, coaxial cable, fiber optic cable, and the like. Furthermore, metallic structural elements could also be used to transport repeater signals. 
     The specific modulation techniques, frequencies, data rates, and so can be optimized for the specific Comm. Path(s) selected. While BPL has been referenced in this disclosure, it is not intended to limit the invention to any specific signal characteristics or Comm. Path conversion and coupling procedures