# 119 (e) (1) to U.S. Provisional Application No. 60/106, 050 filed on October 28, 1998.

TECHNICAL FIELD OF THE INVENTION The present invention relates generally to communication services. In particular, this invention relates to a laser based wireless communications system and method which transmits both dispersed and focused laser energy.

BACKGROUND OF THE INVENTION Current communication systems use both lasers and photodiodes. Wired communication systems couple laser energy into an optical fiber and transmit that laser energy to a receiving photodiode. Transmission distances for wired communication systems can be in excess of 1,000 km supporting data rates of 6.0 Gbps and higher.

Wireless communication systems utilize lasers to transmit coherent and focused laser energy through space to a receiving photodiode. Typical atmospheric transmission distances for wireless communication systems are 50 meters (0.03 miles) to 20 kilometers (12.4 miles) and may support data rates as high as 155 Mbps or greater.

Wireless laser communications systems, which are primarily used for point-to-point communication, focus the laser energy in such a way as to minimize the laser beam

spot size. As distance increases, the laser beam spot size increases. Most existing laser communication systems operate at a wavelength of 870 nanometers (nm). At this wavelength, transmission distance is limited by atmospheric conditions such as dust, rain, and humidity. Transmission distance may also be limited by the stability of the platforms the transmitting'-and receiving elements are mounted to.

Two basic methods of modulating a laser device within a wireless communications system are through field modulation and intensity modulation. Field modulated data comes in the form of a continuous wave and serves as a very high-speed carrier. Much higher bandwidths can be supported using continuous wave methods, but usually have shorter data transmission distance. Intensity modulation provides for varying the optical intensity and power in accordance with a modulation rule. Each data bit is represented by the presence or absence of a pulse of laser energy. Most current wireless communication systems use intensity modulation which is easier to detect, but is limited in bandwidth.

A system and method for incorporating higher power laser diodes, improved photodiodes, dispersing laser energy, multiple repeating transceivers, existing RF transmission technology, and a novel topology will resolve most of the limitations imposed on current wireless laser communications systems.

SUMMARY OF THE INVENTION The present invention provides a laser based wireless communications system and method which substantially

eliminates or reduces disadvantages and problems associated with previously developed laser based wireless communication systems and methods.

More specifically, the present invention provides a laser based wireless communications system and method. The laser based wireless communications system and method of the present invention includes a transceiver unit, an external transceiver unit (or head end), and a data feedback unit. The transceiver unit receives data from a data input source. The external transceiver unit continuously detects and receives transceiver modulated laser energy from the transceiver unit, manipulates the transceiver modulated laser energy yielding external transceiver manipulated laser energy, and transmits the external transceiver manipulated laser energy to the data feedback unit. The external transceiver unit also receives data feedback unit manipulated laser energy from the data feedback unit, manipulates the data feedback unit manipulated laser energy yielding external transceiver manipulated laser energy, and transmits the external transceiver manipulated laser energy back to the transceiver unit or other external transceiver units.

The present invention provides an important technical advantage by providing laser based wireless communications system and method which operates at a longer wavelength than current laser based wireless communication systems, thus improving transmission distances in atmospheric conditions such as dust, rain, and humidity.

The present invention provides another important technical advantage by providing laser based wireless communications system and method which eliminates the need

for platforms, such as towers, thus significantly reducing the cost of setting up the laser based wireless communications system. However, the present invention may be configured to be used with or without platforms.

The present invention provides another important technical advantage by providing laser based wireless communications system and method where the laser beam is dispersed to end users and point-to-point within the communication system which provides for better communication.

The present invention provides another important technical advantage by providing laser based wireless communications system and method where the size of the laser beam may automatically adjust according to the weather conditions.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numerals indicate like features wherein: FIGURE 1 shows one embodiment of a laser based wireless communications system comprising a data input source, a transceiver unit, an external transceiver unit, and a data feedback unit; FIGURE 2 shows one embodiment of a laser based wireless communications system comprising an originating signal driver, a transceiver unit, an external transceiver unit, an internal transceiver interface unit, an internal

transceiver, an interface unit, and a mobile external transceiver; FIGURE 3 shows one embodiment of the originating signal driver; FIGURE 4 shows one embodiment of the transceiver unit; FIGURE 5 depicts point-to-point connectivity between two transceiver units; FIGURE 6 shows a side view of the laser transmitting unit; FIGURE 7 illustrates conically dispersed laser energy; FIGURE 8 illustrates rectangularly dispersed laser energy; FIGURE 9 shows a side view of the photodiode receiving unit; FIGURE 10 shows an end view of the photodiode receiving unit; FIGURE 11 shows a transceiver hub arrangement; FIGURE 12 details the transceiver hub mounting; FIGURE 13 depicts point-to-point connectivity from a transceiver hub to remote transceivers; FIGURE 14 illustrates the transceiver hub and the various operation modes supported; FIGURE 15 depicts a laser based wireless communication system cell; FIGURE 16 illustrates system connectivity methods; FIGURE 17 shows an external transceiver; FIGURE 18 illustrates the connectivity from the external transceiver to the internal transceiver interface unit; FIGURE 19 shows an internal transceiver; FIGURE 20 illustrates examples of interface units;

FIGURE 21 depicts a method of internal wireless connectivity; FIGURE 22 shows a mobile external transceiver; FIGURE 23 illustrates a front view of one embodiment of an external transceiver; FIGURE 24 illustrates a side view of one embodiment of an external FIGURE 25 illustrates a top view of one embodiment of an external transceiver; FIGURE 26 depicts a functional diagram of a head end; and FIGURE 27 depicts a functional diagram of a laser based wireless communication network.

DETAILED DESCRIPTION OF THE INVENTION Preferred embodiments of the present invention are illustrated in the FIGURES, like numerals being used to refer to like and corresponding parts of the various drawings.

The laser based wireless communications system and method of the present invention includes a transceiver unit, an external transceiver unit, and a data feedback unit. The transceiver unit receives data from a data input source. The external transceiver unit continuously detects and receives transceiver modulated laser energy from the transceiver unit, manipulates the transceiver modulated laser energy yielding external transceiver manipulated laser energy, and transmits the external transceiver manipulated laser energy to the data feedback unit. The external transceiver unit also receives data feedback unit manipulated laser energy from the data

feedback unit, manipulates the data feedback unit manipulated laser energy yielding external transceiver manipulated laser energy, and transmits the external transceiver manipulated laser energy back to the transceiver unit or other external transceiver units.

The laser based wireless communication system and method of the present invention is capable of providing high-speed broadband full duplex data services. These services may include, but are not limited to cable television, high definition television, video-on-demand, high-speed internet connectivity, telecommunications, personal communications services, local area network, wide area network, other analog data formats, other digital data formats, and radio frequency communications.

FIGURE 1 depicts one embodiment of a laser based wireless communications system 100 comprising a data input source 75, a transceiver unit 30 (or head end), an external transceiver unit 39, and a data feedback unit 76.

The transceiver unit 30 receives the input data from the data input source 75, processes the input data for diode laser modulation in the support electronics section 27, and transmits the processed input data to the laser transmitting unit 28. The laser transmitting unit 28 modulates the processed input data and transmits the resulting modulated laser energy to the external transceiver 39.

The transceiver unit 30 also detects for a modulated signal from the external transceiver 39 at the photodiode receiving unit 29. The photodiode receiving unit receives the modulated signal, separates the modulated signal from background noise yielding an output signal, and transmits

the resulting output signal to the electronics support section 27.

The external transceiver 39 continuously detects and receives modulated laser energy from the laser transmitting unit 28 of transceiver 30 and transmits the modulated laser energy to a data feedback unit 76. The external transceiver 39 also receives laser energy from the data feedback unit 76 and retransmits the laser energy back to the transceiver unit 30.

FIGURE 2 depicts another embodiment of a laser based wireless communications system 100. In this embodiment, the originating signal driver 51 serves as the data input source. The data feedback unit 76 includes an internal transceiver interface unit 56, an internal transceiver 60, an interface unit 61, and a mobile external transceiver 68.

The originating signal driver 51, shown in FIGURE 3, is the primary interface between the various electronic data service providers and the laser based wireless communication system 100. The originating signal driver 51 has a number of input/output ports 45-49 for interfacing between electronic data service providers or other output signal processing systems and the laser based wireless communications system 100. It accepts inputs in multiple forms including video on demand, analog data input/output, telephone switch input/output, digital data input/output, and high definition television and cable television input/output. Each of these signal inputs and outputs is supported by a service provider. The cable television inputs and outputs would be serviced by a local or national cable television service provider. The cable television service provider would provide a connection to the

originating signal driver 51 instead of or in addition to an existing installed cable plant. The originating signal driver 51 processes, converts, and multiplexes the multiple input signals it receives from the multiple electronic providers into a coaxial cable 50 and transmits the input data to an electronics support section 27 of transceiver 30 for atmospheric transmission.

The originating transceiver unit 51 also receives data from a number of electronic support sections 27 which are part of different transceiver units 30 through coaxial cable 50 or other output signal processing systems. The originating transceiver 51 can then transmit the received data back to the multiple electronic service providers. The originating signal driver 51 is capable of full duplex operation in excess of 30 GHz.

The originating signal driver 51 is derived from existing cable television satellite transceivers. These systems are capable of receiving and transmitting information in the GigaHertz range from orbiting communications satellites. The originating signal driver 51 also employs components of existing cable television head-end or cable plant drivers. The cable plant driver accepts data formatted in a specific analog format for directly modulating laser diodes. The originating signal driver 51 also uses components derived from existing net interface units. Net interface units provide data encoding in a packetized format. In addition the originating signal driver 51 employs digital signal processing technology and pseudo-random noise modulation (PRN) in addition to other modulation methods.

The transceiver unit 30 receives the input data from the original signal driver 51, processes the input data for diode laser modulation in the support electronics section 27, and transmits the processed input data to the laser transmitting unit 28. The laser transmitting unit 28 modulates the processed input data and transmits the resulting modulated laser energy to the external transceiver 39.

The transceiver unit 30 also detects for a modulated signal from the external transceiver 39 at the photodiode receiving unit 29. The photodiode receiving unit receives the modulated signal, separates the modulated signal from background noise yielding an output signal, and transmits the resulting output signal to the electronics support section 27.

The external transceiver 39 continuously detects and receives modulated laser energy from the laser transmitting unit 28 of transceiver 30 and transmits the modulated laser energy to an internal transceiver interface unit 56. The external transceiver 39 also receives laser energy from the internal transceiver interface unit 56 and retransmits the laser energy back to the transceiver unit 30. The external transceiver 39 and internal transceiver interface unit 56 are connected through a wall or barrier 59 by a coaxial cable 58.

The internal transceiver interface unit 56 receives input and output data from the external transceiver 39 and the internal transceiver 60, thus providing full duplex connectivity. The internal transceiver interface unit 56 also supports additional addresses for each internal transceiver 60 and associated interface units 61.

The internal transceiver 60 receives input data from the internal transceiver interface unit 56 and provides line-of-site connectivity to a function specific interface unit 61. The internal transceiver 60 also receives data back from the function specific interface unit 61 and transmits the data back to the internal transceiver interface unit 56 as well as other internal transceivers 60.

Mobile external transceiver 68, which may be mounted to an automobile, aircraft, or other mobile structure, is designed to receive and transmit data to and from external transceiver 39.

FIGURE 4 shows a depiction of the transceiver unit 30.

The transceiver unit consists of the a laser transmitting unit 28, a photodiode receiving unit 29, and support electronics section 27. The support electronics section 27 is connected to the originating signal driver 51 through coaxial cable 50. FIGURE 5 depicts the point-to-point connectivity between two transceiver units 30 using focused laser energy 31. The distance between the transceiver units 30 is in excess of thirty kilometers.

FIGURE 6 depicts the various components of the laser transmitter unit 28 which embody principles of the invention. The laser transmitter is contained within the outer housing 1 which provides protection for the internal components and a means of mounting the laser transmitter unit 28 to other elements. The inner laser and lens housing 8 provides support for the optical lenses 11 and 12 and the laser diode 7. The grooved adjustment rail 9 provides support for focusing lens 13 and allows lateral movement of focusing lens 13. The lens adjustment rail 3

is a fixed lateral gear which is adjusted using the lens adjustment drive gear 4. The lens adjustment module 2 may be remotely activated to provide for the lateral movement of focusing lens 13. The protective lens 16 provides protection from atmospheric conditions and allows the passage of laser energy out of the laser transmitter unit 28. The laser diode 7 is connected to the support electronics section 27 of the transceiver unit 30 or another data input source through connector 6.

Data inputs in the form of electrical signals are processed in the support electronics section 25 for laser diode modulation. Laser diode modulation may be direct modulation or external modulation. The modulation format may be intensity or field modulation depending on the application and system requirements. The modulation method may be frequency modulation, amplitude modulation, pseudo- random noise modulation, or other selected modulation scheme to meet system requirements.

The modulated laser energy 10 is output directly into a series of optical lenses 11 and 12. The optical lenses collimate the laser energy and provide a specific transmission output pattern. The specific output transmission pattern may be focused, conically dispersed, or rectangularly dispersed, or another transmission pattern may be used to meet system requirements. The collimated laser energy output 14 is focused or defocused by focusing lens 13. The resultant focused or dispersed laser energy 15 is passed through the protective lens 16. The protective lens 16 provides wavelength filtration to concentrate the quantity of transmitted photons and

provides protection for the components within the outer housing 1.

As focusing lens 13 is moved by the lens adjustment module 2, lens adjustment rail 3 and the lens adjustment drive gear 4, the lateral distance 5 determines the laser output mode. As focusing lens 13 is moved in one direction the effect is focused laser energy 31 as depicted in FIGURE E 5. Focused laser energy 31 provides the greatest distance capability. As focusing lens 13 continues to be altered the effect shifts to the conical dispersed mode 32 as shown is FIGURE 7. The conical dispersed mode 32 provides the shortest data transmission distance since the laser power is spread through the volume of the cone. FIGURE 8 depicts the rectangular dispersed mode 33. In the rectangularly dispersed mode 33 the laser energy is somewhat more focused and has a slightly greater data transmission distance.

The laser transmitting unit 28 provides data transmission rates in excess of 6.0 GHz. In the point-to- point mode, focused laser energy 31, the transmission distances are in excess of 32 kilometers. In the conical dispersed laser energy mode 32, the transmission distances are in excess of 5 kilometers. In the rectangularly dispersed laser energy mode 33, the transmission distances are in excess of 6 kilometers. The bandwidth available for all operational modes is in excess of 6.0 GHz.

The photodiode receiving unit 29, shown in FIGURE 9, consists of a protective filtering lens 17 which acts as a white light noise filter, a wavelength specific filter 20, a photodiode 19, support electronics 25, and an output port 26. The output port 26 connects the photodiode receiving

unit 29 to the support electronics section 27 of transceiver 30.

The function of the photodiode receiving unit is to detect an appropriately modulated signal, separated the modulated signal from background noise, format the received signal into the identical format it is transmitted in, and connect it to the originating signal driver 51 through the electronics support section 27 of transceiver 30 or other output signal processing system.

The protective filtering lens 17 which acts as a white light noise filter reduces the effect of background noise by reducing the number of photons which do not contain appropriately modulated data. Additional filtering is provided by the wavelength specific filter 20. These two filters reduce the background noise to a point where the quantity of appropriately modulated photons is sufficient to replicate the transmitted data signal.

The photodiode 19 is selected to meet system requirements and converts the detected photons into a small electrical output signal. The small electrical output signal is processed by the support electronics section 25 back to the format of the appropriate modulation method.

This processed signal is then output to the originating signal unit through the support electronics section 27 of transceiver unit 30 for additional processing.

FIGURE 9 illustrates the focused or dispersed laser energy 15 entering the photo diode receiving unit 29 through protective and filtering lens 17. The protective lens 17 reduces the effects of background noise from other photon sources. Laser energy 15 is focused by the concave lens 18 into a concentrated and highly focused laser energy

21. Laser energy 21 is then additionally filtered by a wavelength specific filter 20. This filtering reduces the number of unmodulated photons before being detected by photodiode 19. Mirror photodiode positioning housing 22 may be adjusted into the mirror adjustment space 24 to allow focusing of the mirror and photodiode relative to laser energy 15. The support electronics section 25 contains pre-amplification, signal regeneration, and digital signal processing electronics and is connected to the support electronics section 27 of the transceiver unit 30 through connector 26. The outer housing 23 provides protection for the internal components and allows mounting to other elements.

FIGURE 10 is an end view of the photodiode receiving unit 29 depicting the relationship of the concave mirror 18 to the photodiode 19. The use of concave mirror 18 allows for a smaller diameter aperture to focus the laser energy 15.

When transceiver units 30 are combined together they form a transceiver hub 74. A suggested configuration for transceiver units 30 is shown in FIGURE 11. This configuration consists of eight transceiver units 30 arranged in a circular configuration with each transceiver unit 30 being positioned at a forty-five degree angle relative to the adjoining transceiver unit 30. This suggested configuration is defined as a transceiver hub 74.

The transceiver hub 74 is positioned parallel to the ground. The top half of the transceiver hub mounting bracket 34 is attached to all of the transceiver units 30 and to the bottom half of the transceiver hub mounting bracket 35 as shown in FIGURE 12. The upper mounting

bracket 34 and the lower mounting bracket 35 may be segmented to provide autonomous mounting for each transceiver unit 30 within a defined transceiver hub 74. A stabilization platform 36 provides vibration isolation between the tower mounting plate 37 and the mounted transceiver hub 74. Transceiver hubs 74 are designed to be placed on top of towers, buildings, or any structure of sufficient height to provide line of light connectivity to other transceiver hubs 74 or other transceiving units 30.

In addition, the stabilization platform maintains alignment with distant central transceiver hubs 38. This alignment is maintained through a laser gyroscopically maintained gimbal based alignment mechanism. The stabilization platform 36 may be segmented to provide autonomous vibration isolation and alignment for each transceiver unit 30 within a central transceiver hub 38.

The tower mounting plate 37 is used to securely attach the central transceiver hub 38 to an elevated tower or structure.

The central transceiver hub 38 with point-to-point focused laser energy 31 connectivity is depicted in FIGURE 13. The remote transceiver units 30 are autonomously mounted which allows them to adjust the maximize the received laser energy 31. The stabilization platform, which is provides deviation inputs from the support electronics package 27 in the transceiver units and the support electronics 25 in the photodiode receiving units, allows constant monitoring of the received power relative to the stability and alignment of the transceiver units 30.

In this way, optimized connectivity is continuously

maintained regardless of wind or other atmospheric conditions.

Each transceiver unit 30 can be autonomously adjusted or may be adjusted and aligned within the central transceiver hub 38. Each central transceiver hub 38 may have each transceiver unit 30 configured for a different operating mode as shown in. :,. FIGURE 14. FIGURE 14 depicts a central transceiver hub 38 configured to support focused laser energy 31, conical dispersed laser energy 32, and rectangular laser energy 33. In addition each central transceiver hub 38 has the capability of aligning itself to optimize transmission and reception of laser energy and reconfiguring its operational mode to maintain system integrity and connectivity.

A suggested topology for the laser based wireless communication cell is shown in FIGURE 15. Other topologies suggested are a single central transceiver hub 38 supporting multiple external transceivers 39 or other topologies as geography or applications may suggest. The topology in FIGURE 15 consists of four central transceiver hubs 38 consisting of eight transceiver units 30. Point- to-point connectivity is achieved through focused laser energy 31 between the four central transceiver hubs 38A, 38B, 38C, and 38D. Connectivity from the central transceiver hubs 38 and the external transceivers 39 is accomplished with rectangularly focused laser energy 33 in order to maximize signal density. Each external transceiver 39 receives rectangularly focused laser energy 33 and automatically retransmits the received signal and the added user data using conical laser energy 32. Conical laser energy 32 is used to improve shorter distance

connectivity between external transceivers 39 while minimizing the possibility of signal interference from adjoining external transceivers 39. Conical laser energy may be narrowly dispersed to ensure that the receiving external transceivers 39 are in continuous communication with transmitting external transceivers 39. Further laser energy may be dispersed such that only one receiving external transceiver 39 is illuminated by a transmitting external receiver 39.

In this suggested cell, central transceiver hub 38C transmits data using rectangularly focused laser energy 33 which is received by external transceiver 39D. External transceiver 39D retransmits the received signal which is detected by external transceiver 39E. External transceiver 39E repeats the signal which is then detected by external transceiver 39B. Each external transceiver 39 both repeats the originating signal and adds and removes individual user data. The data eventually connects from any given external transceiver 39 back into the central transceiver hub 38 and eventually returns to the originating signal driver 51.

Connectivity between laser based wireless communication system cells may be accomplished by interconnecting transceiver hubs 74, satellite up/down link, existing systems interconnected through the originating signal driver 51, or other means available.

Since the external transceivers 39 may have the receive threshold adjusted to detect the weakest discernible signal, proliferation of the signal is encouraged and data integrity maintained.

FIGURE 16 depicts methods of maintaining connectivity within a cell. Transceiver unit 30 transmits a signal

using focused laser energy 31. The focused laser energy 31 is detected by the external transceiver 39 on structure 41 and is reflected by structure 41. The reflected laser energy is reflected by structure 44 and received by the external transceiver 39 on structure 43. The external transceiver 39 on structure 43 retransmits the received signal using conical laser-energy 32 which is received and retransmitted by the external transceiver 39 on structure 42. The conical laser energy 32 is then received by transceiver unit 30B. A similar process is followed for establishing connectivity from transceiver unit 30B to transceiver unit 30A.

The external transceiver unit 39, shown in FIGURE 17, consists of a laser transmitter unit 53, a photodiode receiving unit 52, support electronics, and an input/output port 54 and 55 to the internal transceiver interface unit 56. The external transceiver 39 is generally mounted externally on a structure such as a house or office building.

The function of the external transceiver 39 is to detect dispersed laser energy and to transmit dispersed laser energy. In addition, it adds data signals from a specific address for transmission into the system. The dispersed laser mode is usually conical. The detected laser energy is connected both to a repeater section and to an electronic support section of the external transceiver 39. The repeater section reformats the received data signal and re-transmits it in the original received format.

The electronics section processes the received data signal and isolates data signals specifically for the designated user. This is accomplished through assigning a specific

internet protocol address to a specific user or by addressing data by another method. The received data which is designated for a specific address is processed by the support electronics section and connected to the internal transceiver interface unit 56.

In addition the address header is checked to identify the data as specifically for the designated user. If this is the case, the data addressed to the specific user is removed, amplified, processed, and connected either to the existing internal wiring through connector 54 or to the internal transceiver interface unit 56 through connector 54.

The external transceiver may have the signal detection threshold adjusted in order to minimize cross-talk between co-located external transceivers. By adjusting the detectable level threshold, data signal propagation is increased relative to the number of external transceivers within a geographic region. The more external transceivers populating a given geographic area, the greater the data signal density and signal integrity is improved.

In FIGURE 18, rectangularly focused laser energy 32 is received by the external transceiver 39. The received data which is specifically addressed for this structure is connected through wall or barrier 59 using coaxial cable 58 into the internal transceiver interface unit 56. The internal transceiver interface unit 56 provides full duplex connectivity between the external transceiver 39 and the internal transceiver 60. The input and output data from the external transceiver 39 is through coaxial cable 58.

The input and output data supporting the internal transceiver 60 is optical using a light emitting diode 53

and a photodiode 52. The internal transceiver interface unit 56 has a light emitting diode 57 as a transmitter and a photodiode 52 as a receiver. The internal transceiver interface unit supports additional addresses for each internal transceiver and associated interface units. A master address is assigned to each specific user. A sub- address is assigned by theeinternal transceiver interface unit for each internal transceiver and a sub-sub-address is assigned for each interface unit. The internal transceiver interface unit is capable of supporting more than 5 sub- address layers.

The internal transceiver 60, shown in FIGURE 19, provides full duplex connectivity to other internal transceivers 60 and full duplex connectivity to the address and function specific interface units 61 and 62 as shown in FIGURE 20. The internal transceiver 60 uses a light emitting diode 57 as a transmitter and a photodiode 52 as a receiver. The internal transceiver 60 is usually placed within line-of-sight of the internal transceiver interface unit 56. Interface units 61 and 62 are built into applications specific connectors such as the"RJ"series for local area network and telephone applications and"DB" series connectors for use on computer products. Interface units 61 and 62 may be embedded into any application specific device connector. The interface units 61 and 62 use a light emitting diode 57 as a transmitter and a photodiode 52 as a receiver. The internal transceiver 60 assigns specific addresses to each unique interface unit 61 and 62. The internal transceiver interface unit 56 in conjunction with the internal transceiver 60 is capable of supporting at least five sub-address layers.

The internal transceiver 60 is designed to be mounted to a ceiling or wall internal to a structure. It preferably is line-of-sight to the internal transceiver interface unit 56 or line-of sight to another internal transceiver 60 which provides connectivity to the internal transceiver interface unit 56.

FIGURE 21 illustrates.. internal connectivity. The external transceiver 39 receives, transmits, and removes addressed data for a specific user. The user specific data in connected through wall or barrier 59 to the internal transceiver interface unit 56 which assigns a sub-address for each internal transceiver 60. The internal transceiver 60 then assigns a sub-sub-address to devices 61,62, and 63. As each device has a unique address it may then simultaneously transmit and receive data through the internal transceiver 60. An internal device may also connect with other internal devices through the internal transceiver 60. An internal device such as interface device 61 may then communicate with other similar devices internally through the internal transceiver 60 or externally through the internal transceiver 60 to the internal transceiver interface unit 56 to the external transceiver 39 and back into the laser based wireless communication cell 100.

The combination of interface units 61 and internal transceivers 60 may be applied to local area networks.

Since each device has a unique address throughout a given structure the use of interface units 61 and internal transceivers 60 provide a wireless connection infrastructure for networks. In addition connectivity to internet is provided through the internal transceiver

interface unit 56 and the external transceiver 39. The external transceiver 39 connects to and from the transceiver hub 74 and the originating signal driver 51.

Telephone connectivity is supported by the telephone interface unit 61 to and from the internal transceiver 60 which is then either connected to another internal telephone interface unit 61 or to the internal transceiver interface unit 56. The connectivity infrastructure remains essentially the same for any type of data signal or device type.

To support mobile applications there are two varieties of mobile external transceivers. The smaller of these is designed to be integrated into telephones and portable computers to support system connectivity.

The mobile external transceiver 68 shown in FIGURES 22A, 21B, and 21C functions in the same manner as the external transceiver 39. The mobile external transceiver 39 is designed to be mounted to an automobile, aircraft, or other mobile structure. The mobile external transceiver 68 consists of photodiode receiver 52 which is mounted within housing 65 and through the clear lens and filtering plate 66 above the flexible reflective sheet 71. A laser diode 53 is mounted within housing 65 and through the protective lens 64. Both the laser transmitting unit 28 and photodiode receiving unit 29 are internally connected to the support electronics 73. The flexible reflective sheet 71 is connected to the housing 65 by springs 69. The entire assembly is connected to the external surface of the mobile unit with mounting plate 70.

As velocity increases the air flow through air intake/outlet 68A increases. As the air flow increases,

the flexible reflective sheet 71 distorts as shown in FIGURE 22B. The distortion is directly proportional to velocity and provides a constantly changing mechanism for focusing laser energy onto the photodiode 52. The focal length of the reflected laser energy will increase relative to velocity. As the focal length increase the focus of the reflective sheet 71 becomes smaller thus concentrating more energy onto photodiode 52. The flexible reflective sheet 71 increases in depth within the plenum 67 until it is restrained by the air pressure/vacuum differences as shown in FIGURE 22C which represents the maximum energy focus.

This mechanism allows for a stable concentration of appropriately modulated photons at the photodiode 52 regardless of velocity or acceleration.

The external transceiver is presented in FIGUREs 23 through 25. The external Transceiver 200 is a unit designed to mounted at the peak of a slanted roof or at the top of a building. It consists of three main elements: A Protective Sphere 202 which houses the diameter receiver mirror 204, the laser module 206 and the laser optics 208. The protective sphere 202 can be rotated 360 degrees horizontally and tilted from 0 degrees to 90 degrees vertically.

Mounting pipe 210 which provides extension above the peak of a roof or the edge of a building.

Electronics Section 212 which contains the transmitter electronics 214 and the receiver electronics 216. In addition it contains the input/output port 220 to the structure on which the External transceiver 200 is mounted and the power input 218 from the building.

Multiple mounting flanges 222 are attached to the outer case of the Electronics Section 212 to allow maximum flexibility for connecting directly to the building. At least one restraining straps 224 retains the mounting pipe 210 by being bolted into the outercase of the Electronics Section 212. This minimizes vibration by improving stability. Transmitter electronics 214 are positioned less than 36"from laser module 206. This allows the data rate of 2.48 Gbit/sec or greater to be transferred to the laser module 206. The Receiver Electronics 216 is connected to the Collimator 226, which is positioned in the center of the Mirrors 204, by a single mode optical fiber. Collimator 226 is held in position by 4 Collimator Support Bars 228.

These bars are hollow and the single mode optical fiber (not shown) is threaded through the support bar 228 and into the Mounting Pipe 210. The optical fiber is then fed out of Mounting Pipe 228 into the Receiver Electronics 216 In the embodiment shown, Mirrors 204 are contained inside a section of PVC Pipe 230 and epoxied to the back of the Mounting Flange 232. FIGURE 24 presents a side view of External transceiver 200. In this specific embodiment Collimator 226 is wavelength specific at 1550 nm as is the Daylight Filter 234.

Protective Sphere 202 is constructed of a material designed to block white light sources. The spherical shape, or similar shape, of the Protective Sphere minimizes the chance of foreign materials adhering to the surface beneath the horizontal equator of Protective Sphere 202. As Collimating Lens 208 is located in the lower hemisphere, Collimating Lens 208 should remain reasonably clean.

Protective Sphere 202 may be constructed of 2 hemispheres

epoxied together and may be cleaned with a water hose.

While Protective Sphere 202 is not hermetically sealed, the units contained within the Protective Sphere 202 are hermetically sealed.

FIGURE 24 depicts a side view of External Transceiver.

Mounting Pipe 210 is shown mounted to the back of the electronics section 214. Restraining Straps 224 are bolted directly into the structure containing electronics section 214 to reduce vibration. Power is provided from the structure via power input 218.

FIGURE 25 depicts External Transceiver 200 as viewed from above. This Figure depicts the relationship of the Mounting Pipe 210 to the other elements of external transceiver 200. The PVC Pipe is shown to contain the mirror assemblies. Mounting Pipe 210 passes through PVC Pipe 230.

In an additional embodiment of the present invention the transceiver unit may be a Head End as described below.

FIGURE 26 depicts the head end.

Head End 300 (HE): HE 300 gathers various data streams such as video 302, telephone 304, Internet 306, and other like interactive data streams 308 for transmission over an area containing thousands of users. HE 300 multiplexes the data streams together and converts them to a single laser output. HE 300 may contain from 1 to 4 laser/PIN transceiver units (or sub-head end 310). Head End 300 is connected to Sub-Head End 310 either by optical fiber 312 or by laser link 314. Head End 300 performs the following:

System Console 316 allows an operator to monitor and control the operation of the network from a single location.

HE 300 maintains the network database 318. The database 318 contains data defined, gathered, and used by HE 300 to perform the following functions: (1) Initialization Control-Initializes the network and all of its elements, including the backbone. This function will also automatically and dynamically react to network problems to rapidly heal the system in the face of disruption from power failures, bad weather, and other disruptive events.

(2) Sub-Head End Control Function-Controls the local Sub-Head End and all remote Sub-Head Ends attached to the network; controls all communications channels, data gathering activities, and control loops for the Sub-Head Ends.

(3) Bandwidth Allocation-the automatic and dynamic reallocation of Internet Bandwidth as needed to temporarily allocate any end user additional bandwidth.

(4) Tuning Control-Continually monitor the health and operation of the network and all laser links including the laser links that are not primary data paths.

(5) Service Function-Assists in the installation and maintenance of Network Components. This includes the generation of an action plan and topological map automatic real time exchange of information while service personnel are on-site, and record keeping of such installation data such as GPS readings, signal levels, error rates, etc. In addition this function will coordinate the configuration of the entire system to accommodate scheduled events and

different operating environments that may arise. Such events might include reserved bandwidth, special events, and routine maintenance; (6) Recording Systems-record data for the following applications: a) Snapshot Data-gathering streams of data that reflect the operation,, of the system. b) Network Operation Parameters-Accumulate Network statistics that are vital to the operation and expansion of the network. Monitoring, flagging, and controlling congestion within the network as it develops. c) Accounting-Documents the services consumed by each users. d) Video Stream-Monitoring the integrity of the video stream. e) Telephone Stream-Monitoring the integrity of the telephone traffic streams. f) Internet Stream-Monitoring the integrity of the ISP traffic streams.

(7) Security-Implementing the selected security algorithms to effect an acceptable level of security for the digital traffic on the network.

(8) Documents Function-Provides access to system design and control documents for internal personnel and authorized service personnel off-site.

(9) Reformatting Rack-An electronic system which provides the interface between the Sub-Head End, the video media service provider, and control function equipment. It will perform at least the following tasks:

a) Reformat the signals provided by the video media service provider to suit entry into and exit from the Sub-Head End. b) Support dedicated high-speed channels that will allow the Head End control functions to communicate rapidly and reliably with individual Super External Transceivers and External. Transceivers.

(10) Media Service Provider Systems-interface with the reformatting rack, which provides all necessary conversion functions.

(11) One or more Sub-Head End systems-To prepare data for the Super External Transceiver.

(12) One or more Super External Transceivers-To convert the data to laser beams and back again.

Sub-Head End (SubHE) 310: A SubHE 310 is responsible for receiving the HE 300 signal through either laser duplex 314 or optical fiber 312. SubHE routes the broadcast/interactive data to the Super External Transceiver (SuperET) 316 and receiving interactive data from the SuperET 316 and External Transceiver (ET) 300.

Sub-Head End 310 is smaller than the Head End 300. It is designed to off-load Internet 304 and telephone 306 traffic from the network into the Internet 318 and public switched telephone network 320. Sub-Head End 310 receives control and video feed information from the Head End 300, mixes it with Internet data and voice data. The data is formatted for transmission and interfaces with the Network using a Super External Transceiver 316. a) Sub-Head End 310 will contain the interface between a Super External Transceiver 316 and the Telephone

Media Service Provider equipment connected to the PSTN 320.

It will reformat the signals offered by the Telephone Media Service Provider to suite entry and exit from a Super External Transceiver 316. b) Sub-Head End 310 will contain the interface between a Super External Transceiver 316 and the Internet Media Service Provider equipment connected to the local Internet Backbone 318. c) Sub-Head End 310 will contain the interface between a Super External Transceiver 316 and the Head End 300 feed from the Head End reformatting rack 322 from local or equivalent remote feed.

FIGURE 27 depicts a network using the above-described equipment. Super External Transceiver 316 will be a double stacked External Transceiver with twice as many lasers and receivers. Every External Transceiver Ring 324 will have at least one Super External Transceiver 316. Super External Transceivers 316 will communicate with one another so the External Transceiver Rings 324 can communicate with one another much the way a bridge connects two Local Area Networks. The Super External Transceivers 316 will be arranged in a tree structure with a Head End 300 at the root. Using a tree analogy, the Network will have a Head End 300 as the root, Sub-Head Ends 310 as the trunk, Super External Transceivers 316 as the branches, and rings 320 of External Transceivers 200 as the leaves. Each Super External Transceiver 316 will contain at least the following: a) Two External Transceiver Cards each supporting one transceiver.

b) A high-speed board between the External Transceiver Cards that emulates a laser connection between the two External Transceivers. c) Either a second power supply or a larger power supply.

The basic element of the of the Network is the External Transceiver 200 that Will consist of two lasers, two receivers, optics, a circuit board, power supply, and support electronics. External Transceivers 200 will communicate in a ring 324 structure that must incorporate a Super External Transceiver 316.

In summary, the laser based wireless communications system and method of the present invention includes a transceiver unit, an external transceiver unit, and a data feedback unit. The transceiver unit receives data from a data input source. The external transceiver unit continuously detects and receives transceiver modulated laser energy from the transceiver unit, manipulates the transceiver modulated laser energy yielding external transceiver manipulated laser energy, and transmits the external transceiver manipulated laser energy to the data feedback unit. The external transceiver unit also receives data feedback unit manipulated laser energy from the data feedback unit, manipulates the data feedback unit manipulated laser energy yielding external transceiver manipulated laser energy, and transmits the external transceiver manipulated laser energy back to the transceiver unit or other external transceiver units.

Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as described by the appended claims.