WO2001033747A1

WO2001033747A1 - Optical data network

Info

Publication number: WO2001033747A1
Application number: PCT/AU2000/001340
Authority: WO
Inventors: Leonard Charles Layton
Original assignee: Lake Technology Limited
Priority date: 1999-11-01
Filing date: 2000-11-01
Publication date: 2001-05-10
Also published as: AU1119301A

Abstract

An interconnection network including: a series of repeater transceivers (2, 5, 7, 8), the transceivers being arranged, in use, to transmit data signals between them in the form of laser pulses transmitted through the air. The repeater transceivers (2, 5, 7, 8) are mounted, in use, on one or more of the group of existing power poles (3, 6), existing street lighting poles, and existing telegraph poles.

Description

Optical Data Network

Field of the Invention

The present invention relates to the field ol data transmission and. in particular, to the transmission of data to a large numbei ot households or the like. Background of the Invention

Recently, it has become increasingly important to ^"w ire up^" neighboui hoods to a data li ansmission medium which is interconnected to the Internet and provides tor a high bandwidth iorm ol transmission.

Of ten, a severe bottleneck in Internet access is the last connection stage I rom a wired aiea oi international network to households This last connection is commonly known as the "local loop^" oi "the last mile^" The most common Iorm oi data transmission over the local loop is to utilise the li aditional lramewoi k oi telecommunications cai πei s and to utilise copper cable interconnect. Unlorlunateiy. the coppci cable interconnect ot standard telephone systems have limited bandwidth and, in most cases, the telephone system to the home is bandwidth limited to the utilisation ot 56,000 bits pci second via a telephone modem New cable modems often provide a higher bandwidth but requite a total cable rewiring of a neighbourhood. This leads to widespread community dissatislaction with unsightly co-axial cabling systems tor cable television and Internet usage

Wueless alternatives such as satellite and RF data systems have been proposed but sutler I rom legulatory problems with spectrum allocation and, in the case oi satellite, a high speed inbound data rate but very low outbound data rate ( the outbound data rate being typically over standard phone lines.

Summary of the invention

It is an object of the present invention to provide tor an alternative iorm of data transmission to and from e.g. a collection ot houses.

In accordance with a tirst aspect of the present invention, there is provided an interconnection network including a series of repeater transceivers, the transceivers being arranged, in use, to transmit data signals between them in the form of laser pulses transmitted throush the an The repeater transceivers are preferably mounted, in use. on one or more of the group oϊ existing power poles, existing street lighting poles, and existing telegraph poles.

Preferably, the network further comprises a series of terminal transceivers mounted, in use, adjacent to corresponding destination areas to and from which data signals are to be transmitted over the interconnection network, the terminal transceivers being arranged, in use. to transmit to and receive data signals Irom at least one repeater transceiver in the form of laser pulses transmitted through the air

Preferably, the network is configured with some of the destination areas located in one or more ot the group of a harbour, a river or a loreshore environment and some of the repeater transceivers are located on harbour, river or foreshore areas.

At least one of the repeater or terminal transceivers preferably can include a background noise suppression means for suppressing background noise around the repeater or terminal transceivers.

The network can further be arranged, in use. in a manner such that the data signals are transmitted in portions of the network by means ot radio Irequency or other frequency electromagnetic emissions.

The repeater transceivers are preferably powered by one or more of the group of solar panels, power cells, wind or tidal power generation mechanisms

The network can f urther include mirrors to f acilitate, in use, transmission of the data signals aiound obstacles and/or optical libre lor transmitting the data signals, in use. around obstacles. The fibre preferably has optical amplification and/or switching capabilities.

The network is preferably arranged in a manner such that, in use. the laser pulses are beam expanded.

The network may be arranged in a manner such that, in use. backreflection interference is being reduced by means of at least one of the group of Anti reflection coatings, angled or textured surfaces, beam splitters, half-slivered or angled mirrors, modulation of the light signals, and transmission at different wavelengths.

In accordance with a second aspect of the present invention, there is provided a method ol^" providing an interconnection to destination points within an interconnection network, the method including the step ot tiansmitting data signals in the form of laser pulses tiansmitted through the air between a series of repeater transceivers

In accordance with a third aspect of the piesent invention there is piovided a repeater tiansceiver airanged, in use. to tiansmit and leceive data signals in the form of laser pulses tiansmitted thiough the an trom other repeater tiansceivers. tor providing an interconnection to destination points within an inteiconnection netwoi k

The tiansceivei preferably includes means foi , in use, mounting the tiansceivei to on of the group ol existing powei poles, existing street lighting poles, and existing telegraph poles

Brief description of the drawings

Notwithstanding anv othei lorms which may tall within the scope ot the piesent invention pieleired loi ms ot the invention will now be described, by way ot example only with lefeience to the accompanying di awings in which

Fig 1 illustiates schematically the ai rangement ot the piereired embodiment, Fig 2 is a schematic illustration of the design of a repeater module.

Fig 3 illustiates the utilization ot the preferred embodiment in a harboui environment.

Fig 4 illusti ates the utilization of a backing board with a lepeater module so as to minimize background noise

Description of the Preferred and other Embodiments In the preferred embodiment, the infrastructure of the powei supply system and, in particular powei supply poles, is utilised to provide for free space data communication between adjacent power poles As a substantial amount ot power supply is still being provided by oveihead wuing on power poles, the power poles can be utilised as a data staging and transmission device carπei utilising inferred data communications Preferably, high performance, long range line of sight optical data transmission is provided utilising devices such as those available from Astroteira Corporation who market a device able to provide for high speed transmission utilising infrared data communications

The utilisation oi the overhead power supply and power poles has the added advantage that because of the danger of fire and supply interruption, power supply authorities and companies have diligentlv removed tiees and other obstructions from the vicinity of power poles and power lines There is therefore an increased likelihood of line ot sight thoroughfare aiound the city or neighbourhood tiom power pole to power pole

Further, a laige segment ot the worlds population lives close to the sea oi to πveis For example, where a harboui is piesent, then this is a huge lesource of open space that is able to provide line of sight communications to a large number ol homes

The pieterred embodiment therefore comprises a numbei of portions ot hardwaie which most impoitantly include a senes ot repeater modules As iUustiated in Fig 1 , the repeater modules eg 2 aie located on powei poles eg within the line ot sight 4 ot othei modules eg 5 which aie also located on powei poles eg 6 A senes of terminal modules eg 7 are mounted on houses oi buildings and piovide foi end teimination of the data transmission

Powei tor the lepeatei s eg 2 5 can be obtained ti om the power supply on the coi iesponding pole oi alternatively solai panels oi battenes could be utilised The terminal modules 7 aie mounted within a line oi sight ol icpeatei module 8 and powei Ioi the terminal module can be supplied by the end usei The tci minal modules include a lelevant lntei face adaptoi Ioi data delivei y to the end usei s equipment such as computei s telephones, televisions etc

The lepeatei modules e 2, 5, 8 may also contain switching hardwaie that allows data to be routed intelligently to its destination rather than being repeated throughout the network In this manner the operation can be similai to a packet switch netwoi k such as the TCP - IP Intei net Pi otocol

An example schematic sti uctuie ol a lepeater module can be as iUustiated in Fig 2 wheiein a series ot receivers eg 10 are provided for receiving signals from other repeater modules The information received is controlled and routed by a control and routing chip 1 1 to a senes ot transmittei s 12 The control and routing chip 1 1 can be an ASIC circuit implementing i outing opei ation in a similar matter to standard Internet packet routing systems

As a tuither application, the lepeatei modules can themselves be fitted with cellulai telephony base stations or mobile phone communication As a result of^" the likely small cell size, extremely low power portable equipment can be utilised and other frequencies previously unusable can be attained Further the small cell size also fosters a dual use high resolution tracking and navigation utilization of the interconnect The software provided for the overall control ot the system can include a switching network protocol for data transmission, a synchronous broadcast protocol for real time media such as video and a network management software infrastructure to handle billing, routing, fault analysis etc. The utilization ot an in-air laser transmission interconnect can have a number ot benef its. Firstly, the system can utilize a wider bandwidth than say a fibre system because the propagation is not dependant upon frequency as in a dispersive fibre Further, utilizing both wideband links and a switched packet network also increases overall perlormance of the system The system does not require the laying ot fibre cables and can be implemented utilizing commodity parts which can be mass produced. The lacililics can be highly flexible and upgradable as need be Further, other modifications are possible For example, where a river or harbour structure is present, then a repeater module can be located on a headland or around the πvei or the harbour so as to provide for an excellent backbone infrastructure lor the system. A schematic example ot such an ai rangc ent is illustrated in Fig 3 wherein a lepeater module 20 is located on an island structure in a harbour and communicates with a second repeater module 21 located on the foreshores. In order to enhance the performance of the point to point link, each transmitting station as illustrated in Fig. 4 can include a backing board eg. 25 of an arbitrary size which helps discriminate the transmitted signal from background noise

A number of further refinements are possible to the above arrangements For example, in a f irst ref inement, radio ticquency oi other f requency electiomagnetic connections between the pole-mounted repeater/s itch units can be made both between poles and poles and substations These connections can be v ia both directional and general emitters

Further, the system can be mounted on other types of poles including street lighting poles or telegraph poles Further the system can be driven by various power sources including solar panels or other power cells mounted on the poles. Alternatively, wind or tidal power can be provided for remote locations.

The system can further include mirror to transmit around obstacles. Further, this can be extended to utilise fibre transmission to transmit around obstacles before returning to in-air transmission once the obstacle has been passed. The utilisation of fibre segments can allow tor all optical amplification and switching capabilities during transmission.

Further, beam expansion techniques can be used to widen a transmitted beam to a parallel cylinder for eye safety and resistance to scintillation effects can be provided. Suitable arrangements can include Cassegrain or Schmidtt-Cassegrain optics ( such as those set out in US patents 4.054,364 and 5,500.520. Alternative modes of expansion can be provided via beam expansion on the end of a fibre bundle or a lens arrangements

In certain arrangements, it is somewhat less expensive to utilise the same optical path tor both the transmit and receive on a link. Therefore it is desirable to minimize reflections trom the transmitter coming straight back and interfering with the receiver in the same unit. This can be provided by a combination ot the following techniques:

( a) Anti reflection coatings on the f ront and inside surfaces of each unit;

( b ) angled surfaces ai ound a receiver so that ref lections go off at an angle and transmission goes straight through can be used A textured surf ace having zig zag pattern or suitably constructed irregular surf aces can also be used to minimise back reflections

( c ) A beam splitter or hall-slivered, angled mirror may also be suitable Ideally, it is mounted do the same )ob - but mount it close to the photodiode and LED at the local point of the optics to maximize suppression (d) Modulating the light signal with an identifying code (CDMA, FM, etc) that is unique f or each direction

(e) Utilising a separate wavelength for each direction.

It would be appreciated by a person skilled the ai t that numerous variations and/oi modifications may be made to the present invention as shown in the specif ic embodiments without departing tiom the spirit oi scope ot the invention as broadly described The piesent embodiments are, theretoie. to be considered in all respects to be illustrative and not lestπctive

Claims

1. An interconnection network including: a series of repeater transceivers, the transceivers being arranged, in use. to transmit data signals between them in the form of lasei pulses transmitted through the air

2. A network as claimed in claim 1. wherein the repeater transceivers are mounted, in use, on one or more of the group of existing power poles, existing street lighting poles, and existing telegraph poles.

3. A network as claimed in claims 1 or 2. wherein the network further comprises a senes of^" terminal transceivers mounted, in use, adjacent to corresponding destination areas to and from which data signals are to be transmitted over the interconnection network, the terminal transceivers being arranged, in use, to transmit to and receive data signals from at least one repeater transceiver in the form ot laser pulses transmitted through the air

4 A network as claimed in claim 3, wherein the network is configured with some of the destination areas located in one or more of^" the group of a harbour, a river or a foreshore environment and some of the repeater transceivers are located on harbour, river or foreshore areas.

5. A network as claimed in any one of the preceding claims, wherein at least one of the repeater or terminal transceivers includes a background noise suppression means for suppressing background noise around the repeater or terminal transceivers.

6 A network as claimed in any one of the preceding claims, wherein the netwoik is further arranged, in use, in a manner such that the data signals are transmitted in portions ot the netwoi k by means of^" radio frequency or other frequency electromagnetic emissions

7. A network as claimed in any one of the preceding claims, wherein the repeater transceivers are powered by one or more of the group of solar panels, power cells, wind or tidal power generation mechanisms.

8. A network as claimed in any one of the preceding claims, wherein the network further includes mirrors to facilitate, in use, transmission of the data signals around obstacles.

9 A network as claimed in any one of the preceding claims, wherein the network further includes optical fibre for transmitting the data signals, in use. around obstacles.

10. A network as claimed in any one of the preceding claims, wherein the network is arranged in a manner such that, in use, the laser pulses are beam expanded.

11. A network as claimed in any one of the preceding claims, wherein the network is arranged in a manner such that, in use, backreflection interference is being reduced by means of at least one of the group of Anti reflection coatings, angled or textured surfaces, beam splitters, half-slivered or angled mirrors, modulation of the light signals, and transmission at different wavelengths.

12. A method of providing an interconnection to destination points within an interconnection network, the method including the step of transmitting data signals in the form of laser pulses transmitted through the air between a series of repeater transceivers, wherein the repeater transceivers are mounted, in use, on one or more of the group of existing power poles, existing street lighting poles, and existing telegraph poles.

13. A repeater transceiver arranged, in use, to transmit and receive data signals in the form of laser pulses transmitted through the air from other repeater transceivers, for providing an interconnection to destination points within an interconnection network, the transceiver including means for, in use, mounting the transceiver to on of the group of existing power poles, existing street lighting poles, and existing telegraph poles.