Optical communication system
First Claim
1. A method for transferring information within a cellular communications network, comprising acts of:
- transmitting an optical carrier from a first network-element of the network;
modulating the optical carrier with the information;
detecting the modulated optical carrier in an avalanche photo-diode (APD) comprised in a second network-element of the network so as to recover the information; and
altering a gain of the APD responsive to a level of the optical carrier so as to prevent saturation of the APD.
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0 Petitions
Accused Products
Abstract
A method for transferring information within a cellular communications network (20), consisting of transmitting an optical carrier from a first network-element (26A) of the network, modulating the optical carrier (57, 59) with the information, and detecting the modulated optical carrier in an avalanche photo-diode (APD) (150) in a second network-element (24A) of the network so as to recover the information. The method includes altering a gain of the APD responsive to a level of the optical carrier so as to prevent saturation of the APD. Other methods and apparatus are also provided for transferring the information via the optical carrier, and also for using the information transferred.
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Citations
74 Claims
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1. A method for transferring information within a cellular communications network, comprising acts of:
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transmitting an optical carrier from a first network-element of the network;
modulating the optical carrier with the information;
detecting the modulated optical carrier in an avalanche photo-diode (APD) comprised in a second network-element of the network so as to recover the information; and
altering a gain of the APD responsive to a level of the optical carrier so as to prevent saturation of the APD. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 29, 30, 31, 32, 33, 35, 36, 38, 39, 40, 41, 42, 43)
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13. Apparatus for transferring information within a cellular communications network, comprising:
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a first network-element of the network, comprising;
an emitter which is adapted to transmit an optical carrier; and
a modulator which is adapted to modulate the optical carrier with the information; and
a second network-element of the network, comprising;
an avalanche photo-diode (APD) which is adapted to detect the modulated optical carrier so as to recover the information; and
a gain controller which is adapted to alter a gain of the APD, responsive to a level of the optical carrier, so as to prevent saturation of the APD.
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25. Apparatus for transferring information within a cellular communications network, comprising:
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a first network-element of the network, comprising;
a first amplifier which is adapted to receive and amplify a radio-frequency (RF) signal so as to generate a first-amplified-RF-signal;
a detector which indicates attainment of a predetermined level of the received-RF-signal;
a first gain device which is adapted to alter a gain of the first amplifier by a predetermined gain-value responsive to the attainment of the predetermined level; and
an optical transmitter which modulates an optical carrier with the first-amplified-RF-signal and which transmits the modulated carrier; and
a second network-element of the network, comprising;
an optical receiver which receives the modulated carrier and generates a recovered-RF-signal therefrom;
a second amplifier which is adapted to receive and amplify the recovered-RF-signal so as to generate a second-amplified-RF-signal; and
a second gain device which is adapted to alter a gain of the second amplifier by a value substantially equal to a negative of the predetermined gain-value responsive to the attainment of the predetermined level at the first network-element.
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28. Apparatus for receiving information transmitted in a cellular communications network, comprising:
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an optical assembly which is adapted to receive an optical carrier modulated with the information and output the received-modulated-carrier;
a first optical unit which is coupled to receive the received-modulated-carrier at a first end of the first optical unit and to convey the received-modulated-carrier therein;
a first receiver which is coupled to a second end of the first optical unit to receive a first fraction of the received-modulated-carrier and which, responsive thereto, is adapted to generate a first output representative of the information;
a second optical unit which is coupled to the first optical unit so as to convey a second fraction of the received-modulated-carrier into the second optical unit;
a second receiver which is coupled to the second optical unit so as to receive the second fraction of the received-modulated-carrier and which, responsive thereto, is adapted to generate a second output representative of the information; and
a switch which selects from the first and the second outputs responsive to a level of the received-modulated-carrier.
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34. Apparatus for transferring information within a cellular communications network, comprising:
a first network-element of the network, comprising;
an analog-to-digital converter (ADC) which is adapted to convert a radio-frequency (RF) signal to a digital signal, the RF signal being receivable from a transceiver operative within the network;
an optical modulator which is coupled to receive the digital signal and is adapted to modulate an optical carrier with the signal; and
a transmitter which is adapted to transmit the modulated optical carrier; and
a second network-element of the network, comprising;
a receiver which is coupled to receive the modulated optical carrier;
a demodulator which is adapted to recover the digital signal from the modulated optical carrier; and
a digital-to-analog converter (DAC) which is adapted to convert the digital signal so as to recover the RF signal.
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37. Apparatus for transferring information within a cellular communications network, comprising:
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a first network-element of the network, comprising;
a splitter, which is adapted to receive an initial radio-frequency (RF) signal comprising the information and to split the signal into a first RF signal and a second RF signal;
a first optical transmitter which is coupled to modulate a first optical carrier with the first RF signal and to transmit the first modulated optical carrier; and
a second optical transmitter which is coupled to modulate a second optical carrier with the second RF signal and to transmit the second modulated optical carrier;
a second network-element of the network, comprising;
a first optical receiver which is adapted to receive and demodulate the first modulated optical carrier to recover the first RF signal;
a second optical receiver which is adapted to receive and demodulate the second modulated optical carrier to recover the second RF signal; and
a summer which is coupled to add the first and second recovered RF signals so as to regenerate the initial RF signal; and
a first feedback network, coupling the first optical receiver to the first optical transmitter, which alters a first characteristic of the first modulated optical carrier responsive to a first parameter indicative of a first quality of information transferred by the first modulated optical carrier measured at the second network-element.
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44. Apparatus for transferring information within a cellular communications network, comprising:
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a first network-element of the network, comprising;
a first mixer which is adapted to modulate a first RF sub-carrier with a first RF signal;
a second mixer which is adapted to modulate a second RF sub-carrier with a second RF signal;
a summer which is coupled to add the first and second modulated sub-carriers to generate a combined RF signal; and
an optical transmitter which is coupled to transmit an optical carrier modulated with the combined RF signal; and
a second network-element of the network, comprising;
an optical receiver which is adapted to receive the modulated optical carrier and to recover the combined RF signal;
a splitter which is coupled to recover from the combined RF signal the first modulated sub-carrier and the second modulated sub-carrier as separate signals;
a third mixer which is adapted to receive the first modulated sub-carrier and to recover the first RF signal; and
a fourth mixer which is adapted to receive the second modulated sub-carrier and to recover the second RF signal. - View Dependent Claims (45, 47, 49, 50)
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46. A method for transferring information within a cellular communications network, comprising the acts of:
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receiving and amplifying, in a first amplifier comprised in a first network-element of the network, a radio-frequency (RF) signal so as to generate a first-amplified-RF-signal;
altering a gain of the first amplifier by a predetermined gain-value, responsive to the RF signal attaining a predetermined level;
modulating an optical carrier with the first-amplified-RF-signal and transmitting the modulated carrier;
receiving in an optical receiver comprised in a second network-element of the network the modulated carrier and generating a recovered-RF-signal therefrom;
receiving and amplifying the recovered-RF-signal in a second amplifier so as to generate a second-amplified-RF-signal; and
altering a gain of the second amplifier by a value substantially equal to a negative of the predetermined gain-value, responsive to the RF signal attaining the predetermined level.
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48. A method for receiving information transmitted in a cellular communications network, comprising the acts of:
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receiving in an optical assembly an optical carrier modulated with the information and outputting therefrom the received-modulated-carrier;
coupling the received-modulated-carrier into a first end of a first optical unit and conveying the received-modulated-carrier therein;
receiving a first fraction of the received-modulated-carrier in a first receiver coupled to a second end of the first optical unit and responsive thereto generating a first output representative of the information;
coupling a second optical unit to the first optical unit;
conveying a second fraction of the received-modulated-carrier into the second optical unit;
receiving in a second receiver coupled to the second optical unit the second fraction of the received-modulated-carrier and, responsive thereto, generating a second output representative of the information; and
selecting between the first and the second outputs responsive to a level of the received-modulated-carrier.
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51. A method for transferring information within a cellular communications network, comprising the acts of:
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converting, in an analog-to-digital converter (ADC), a radio-frequency (RF) signal to a digital signal, the RF signal being receivable by a transceiver operative within the network;
modulating a n optical carrier with the digital signal; and
transmitting the modulated optical carrier from a transmitter comprised in a first network-element of the network; and
receiving and demodulating the modulated optical carrier in a receiver comprised in a second network-element of the network, so as to recover the digital signal; and
converting the digital signal in a digital-to-analog converter (DAC) so as to recover the RF signal. - View Dependent Claims (52, 53)
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54. A method for transferring information within a cellular communications network, comprising the acts of:
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receiving an initial radio-frequency (RF) signal comprising the information and splitting the signal into a first RF signal and a second RF signal;
modulating a first optical carrier with the first RF signal to produce a first modulated optical carrier and transmitting the first modulated optical carrier from a first optical transmitter in a first network-element of the network;
modulating a second optical carrier with the second RF signal to produce a second modulated optical carrier and transmitting the second modulated optical carrier from a second optical transmitter in the first network-element;
receiving in a first optical receiver in a second network-element of the network the first modulated optical carrier and demodulating the first modulated optical carrier to recover the first RF signal;
receiving in a second optical receiver in the second network-element the second modulated optical carrier and demodulating the second modulated optical carrier to recover the second RF signal;
coupling the first optical receiver to the first optical transmitter by a first feedback network which alters a first characteristic of the first modulated optical carrier, responsive to a first parameter indicative of a first quality of information transferred by the first modulated optical carrier measured at the second network-element; and
adding the first and second recovered RF signals to regenerate the initial RF signal. - View Dependent Claims (55, 56, 57, 58, 59, 60)
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61. A method for transferring information within a cellular communications network, comprising the acts of:
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modulating a first RF sub-carrier with a first RF signal to form a first modulated sub-carrier;
modulating a second RF sub-carrier with a second RF signal to form a second modulated sub-carrier;
adding the first and second modulated sub-carriers to generate a combined RF signal;
transmitting an optical carrier modulated with the combined RF signal from a first network-element of the network;
receiving the modulated optical carrier in a second network-element of the network and recovering the combined RF signal;
separating the combined RF signal into the first modulated sub-carrier and the second modulated sub-carrier;
recovering the first RF signal from the first modulated sub-carrier; and
recovering the second RF signal from the second modulated sub-carrier.
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62. A method for allocating capacity to a network-element operating in a cellular communications network, comprising the acts of:
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providing a plurality of spatially fixed network-elements, each network-element having a respective capacity for transmitting and receiving signals compatible with the cellular communications network;
coupling pairs of the plurality of network-elements by respective optical carriers, each carrier being modulated so as to convey the signals between the respective coupled pair of network-elements; and
transferring at least some of the capacity of the coupled network-elements therebetween via the optical carriers, responsive to a level of the signals detected by the plurality of network-elements. - View Dependent Claims (63)
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64. Apparatus for allocating capacity in a cellular communications network, comprising:
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a first plurality of spatially fixed network-elements, each network-element having a respective capacity for transmitting and receiving signals compatible with the cellular communications network; and
a second plurality of optical carriers, each carrier coupling a pair of the network-elements and being modulated so as to convey the signals therebetween, and being adapted to transfer at least some of the capacity of the coupled network-elements therebetween, responsive to a level of the signals detected by the network-elements.
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65. A method for transferring information within a cellular communications network, comprising the acts of:
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transmitting an optical carrier from a first network-element of the network to a second network-element of the network;
modulating the optical carrier with the information so as to transfer the information from the first network-element to the second network-element;
transmitting a pilot signal from the first network-element to the second network-element;
measuring a received power level of the pilot signal at the second network-element;
generating a mapping between the received power level of the pilot signal and a parameter indicative of a quality of the information transferred from the first network-element to the second network-element; and
adjusting at least one of a transmitted power level of the optical carrier and a communication bandwidth of the optical carrier, responsive to the received power level of the pilot signal and the mapping, so as to maintain a predetermined minimum quality of the information transferred from the first network-element to the second network-element. - View Dependent Claims (66, 67, 68, 69)
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70. Apparatus for transferring information within a cellular communications network, comprising:
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a first network-element of the network, comprising;
an optical emitter which transmits an optical carrier modulated with the information as a modulated optical carrier;
a pilot signal generator which transmits a pilot signal; and
a first central processing unit (CPU) which controls the emitter and the pilot generator;
a second network-element of the network, comprising;
a transducer which receives the modulated optical carrier and generates recovered information therefrom;
a detector which measures a received power level of the pilot signal;
a second CPU which receives the measured power level; and
a memory which stores a mapping between the received power level of the pilot signal and a parameter indicative of a quality of the recovered information, at least one of the first and second CPUs being adapted to adjust at least one of a transmitted power level of the optical carrier and a communication bandwidth of the optical carrier, responsive to the received power level of the pilot signal and the mapping, so as to maintain a predetermined minimum quality of the recovered information. - View Dependent Claims (71, 72, 73, 74)
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Specification