Patent ID: 12261638

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the presently disclosed subject matter. However, it will be understood by those skilled in the art that the presently disclosed subject matter can be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the presently disclosed subject matter.

In the drawings and descriptions set forth, identical reference numerals indicate those components that are common to different embodiments or configurations.

Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as Processor210or the like, include action and/or processes of a computer that manipulate and/or transform data into other data, said data represented as physical quantities, e.g., such as electronic quantities, and/or said data representing the physical objects. The terms “computer”, “processor”, “processing resource”, “processing circuitry”, and “controller” should be expansively construed to cover any kind of electronic device with data processing capabilities, including, by way of non-limiting example, a personal desktop/laptop computer, a server, a computing system, a communication device, a smartphone, a tablet computer, a smart television, a processor (e.g. digital signal processor (DSP), a microcontroller, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc.), a group of multiple physical machines sharing performance of various tasks, virtual servers co-residing on a single physical machine, any other electronic computing device, and/or any combination thereof.

The operations in accordance with the teachings herein can be performed by a computer specially constructed for the desired purposes or by a general-purpose computer specially configured for the desired purpose by a computer program stored in a non-transitory computer readable storage medium. The term “non-transitory” is used herein to exclude transitory, propagating signals, but to otherwise include any volatile or non-volatile computer memory technology suitable to the application.

As used herein, the phrase “for example,” “such as”, “for instance” and variants thereof describe non-limiting embodiments of the presently disclosed subject matter. Reference in the specification to “one case”, “some cases”, “other cases” or variants thereof means that a particular feature, structure or characteristic described in connection with the embodiment(s) is included in at least one embodiment of the presently disclosed subject matter. Thus, the appearance of the phrase “one case”, “some cases”, “other cases” or variants thereof does not necessarily refer to the same embodiment(s).

It is appreciated that, unless specifically stated otherwise, certain features of the presently disclosed subject matter, which are, for clarity, described in the context of separate embodiments, can also be provided in combination in a single embodiment. Conversely, various features of the presently disclosed subject matter, which are, for brevity, described in the context of one exemplary embodiment, can also be provided separately or in any suitable sub-combination.

In embodiments of the presently disclosed subject matter, fewer, more and/or different stages than those shown inFIGS.4and5can be executed. In embodiments of the presently disclosed subject matter one or more stages illustrated inFIGS.4and5can be executed in a different order and/or one or more groups of stages can be executed simultaneously.FIGS.1A,1B,2, and3illustrates a general schematic of the system architecture in accordance with one exemplary embodiment of the presently disclosed subject matter. Each module inFIGS.1A,1B,2, and3can be made up of any combination of software, hardware and/or firmware that performs the functions as defined and explained herein. The modules inFIGS.1A,1B,2, and3can be centralized in one location or dispersed over more than one location. In other embodiments of the presently disclosed subject matter, the system can comprise fewer, more, and/or different modules than those shown inFIGS.1A,1B,2, and3.

Any reference in the specification to a method should be applied mutatis mutandis to a system capable of executing the method and should be applied mutatis mutandis to a non-transitory computer readable medium that stores instructions that once executed by a computer result in the execution of the method.

Any reference in the specification to a system should be applied mutatis mutandis to a method that can be executed by the system and should be applied mutatis mutandis to a non-transitory computer readable medium that stores instructions that can be executed by the system.

Any reference in the specification to a non-transitory computer readable medium should be applied mutatis mutandis to a system capable of executing the instructions stored in the non-transitory computer readable medium and should be applied mutatis mutandis to method that can be executed by a computer that reads the instructions stored in the non-transitory computer readable medium.

One technical problem dealt with by the disclosed subject matter is a need to prevent even stronger jamming signals from interfering with wireless communication and to avoid further division of the electromagnetic spectrum in advance.

One technical solution is to allow for even further spreading the bandwidth of a transmitted signal significantly beyond what is available today, for example spreading the bandwidth of the transmitted signal to about 10 Gigahertz.

Another technical problem dealt with by the disclosed subject matter is that further attempting to spread the transmitted signal bandwidth, using existing techniques, results in a loss that exceeds the profit. The reason being that using existing techniques significantly increases required processing resources. Performing the calculations in real-time in the transmitter and the receiver will require immense resources for sampling, and digital signal processing. Which will lead to a dramatic increase in size, weight, cost, and power consumption. It will also be appreciated that a significant increase in processing gain alone, i.e., no bandwidth increase accordingly, causes a significant reduction in the data rate per user.

Another technical solution is cascading at least two spreaders on the transmitter side and respectively at least two correlators on the receiver side. In some exemplary embodiments, the transmitter's first spreader and the receiver's second correlator can utilize digital signal processing technology. Whereas the transmitter's second (doubly) spreader and the receiver's first (doubly) correlator can be implemented using optical processing technique of the present disclosure.

In some exemplary embodiments, the transmitter's second-spreader and the receiver's second-correlator, of the present disclosure, can be provided for upgrading existing transmitters and receivers having spread spectrum. The upgrade can be implemented by cascading at least one second-spreader to an egress of the existing transmitter and respectively cascading at least one second-correlator to an ingress of the existing receiver. In conclusion, cascading additional spreaders/correlators increases the total processing gain and the total bandwidth of the augmented system.

Reference is now made toFIG.1A, showing a schematic block diagram of a transmitter utilizing a cascaded spread-spectrum system, in accordance with some exemplary embodiments of the disclosed subject matter.

FIG.1Adepicts a transmitter's cascaded spread-spectrum system implemented in a Transmitter (Tx)101of the present disclosure. Tx101is a wireless transmitter designed to encode information originating in an input signal, i.e., a signal having information to be transmitted, by Tx101. Tx101can be also designed to transmit signals having wider bandwidth (BW) than its input signal BW.

In some exemplary embodiments, Tx101is adapted for encoding high bitrate data signals. In some exemplary embodiments, Tx101can comprise a First-Spreader110and a Second-Spreader120connected in series to First-Spreader110egress.

In some exemplary embodiments, First-spreader110multiplies a Data-In-Signal111, comprising information to be transmitted, by a First-Spreading-Sequence (1SpSeq)112, thereby producing a First-Spread-Spectrum-Signal (SS1-Signal)113. It will be noted that spreading-sequences of the present disclosure comprise a number of bits per second (chips per second). Different spreading-sequences can be utilized by Tx101for spreading (encoding) Data-In-Signal111for each transmission uniquely.

It will be noted that 1SpSeq112can have higher chip rate than Data-In-Signal111, bit rate. In some exemplary embodiments, Second-Spreader120multiplies SS1-Signal113by a Second-Spreading-Sequence (2SpSeq)122, thereby producing (generating) a Doubly-Spread-Spectrum-Signal (SS2-Signal)123. It will be noted that 2SpSeq122has higher chip rate than that of SS1-Signal113. It will also be noted that the chip rate of 2SpSeq122is much greater than the chip rate of 1SpSeq112and that either one of the multiplications can be regular multiplication, complex multiplication and any combination thereof, or the like.

Additionally, or alternatively, Tx101can further comprise a Frequency Converter130and a Carrier-Generator131used for modulating SS2-Signal123into an RF Doubly-Spread-Spectrum-Signal (RF-SS2-Signal)132in order to broadcast it with a Transmission-Amplifier (TxAmp)140coupled by an Antenna141.

In some exemplary embodiments, First-Spreader110and Second-Spreader120can be electronically implemented using DSSS technique for encoding Data-In-Signal111and SS1-Signal113respectively. Both First-Spreader110and Second-Spreader120multiply their input stream signals by their corresponded spreading-sequences.

In some exemplary embodiments, a spreading-sequence can be an encoding series, such as pseudo-noise (PN) sequence signal, based on a Barker sequence; a Gold sequence; and any combination thereof, or the like. Additionally, or alternatively, the PN sequence of any one of the spreaders, e.g., First-Spreader110and Second-Spreader120, can be a complex PN sequence. It will be noted that the PN sequence of de-spreaders/correlators implemented in receivers, such as Rx102and Rx300(to be described in detail further below), can utilize a PN sequence that is either identical to the transmitter's PN, or a complex conjugate of the transmitter's PN sequence. It will also be noted that an outcome signal of spreaders, i.e., SS1-Signal113and SS2-Signal123can resemble bandlimited white noise.

In some exemplary embodiments, spreading-sequences, i.e., 1SpSeq112and 2SpSeq122, can be generated by First-Spreader110and Second-Spreader120, respectively. Additionally, or alternatively, either First-Spreader110and/or Second-Spreader120can be provided with spreading-sequences from an external resource such as an external device/processor. In some exemplary embodiments, Data-In-Signal111can be the input stream signal of First-Spreader110, whereas SS1-Signal113(outcome of First-Spreader110) can be the input stream signal of Second-Spreader120, thereby cascading the Second-Spreader120to the First-Spreader120.

In some exemplary embodiments, the function of First-Spreader110and Second-Spreader120is to alter the spectral bandwidth of their respective input signal to a wider spectral bandwidth at their output signal. It should be noted that, a ratio between a BW of the output signal and a BW of the input signal is defined as a processing gain (PG). Thus, PG of First-Spreader110(G1) is given by the BW of SS1-Signal113divided by the BW of Data-In-Signal111. Similarly, PG of Second-Spreader120(G2) is given by the BW of SS2-Signal123divided the bandwidth of SS1-Signal113.

It will be noted that Data-In-Signal111is characterized by high spectral density at a narrow bandwidth, e.g., BW111′. While after encoding Data-In-Signal111, by First-Spreader110, the outcome of SS1-Signal113, is lowered in spectral density over a wider bandwidth, e.g., BW113′. Likewise, after spreading SS1-Signal113, by Second-Spreader120, the outcome of SS2-Signal123is further lowered in spectral density over an even wider bandwidth, e.g., BW123′.

It will be appreciated that the product of G1 (PG of First-Spreader110) by G2 (PG of Second-Spreader120) significantly lowers the spectral energy over a very wide bandwidth, i.e., making the transmission: harder to detect and intercept; less interfering with other channels, and less vulnerable to jamming.

In some exemplary embodiments, the Tx101can be provided as an add-on device, configured to receive at its input (i.e., Data-In Signal111) an RF signal from a transceiver, and then generate SS1-Signal113followed by SS2-Signal123, which will be modulated and transmitted as an RF-SS2-Signal132. Additionally, or alternatively, the RF-SS2-Signal132can be routed back to the transceiver for transmission.

In some exemplary embodiments, the Tx101can be provided as an add-on device, configured to receive (from a transceiver) a first-spread-spectrum signal, such, as SS1-Signal113, and then generate SS2-Signal123, which will be modulated to RF-SS2-Signal132for transmission by either Tx101or the device.

In some exemplary embodiments, the Tx101of the wideband communication system of the present disclosure, is configured to perform a wireless communication transmitting method. In some exemplary embodiments, the transmitting method comprising: obtaining a Data-In-Signal111and spreading it, using First-Spreader110, to SS1-Signal113; followed by spreading the SS1-Signal113, using Second-Spreader120, to SS2-Signal123.

Additionally, or alternatively, the transmitting method can also comprise modulating SS2-Signal123, using Frequency Converter130and a Carrier-Generator131to RF-SS2-Signal132, which can be transmitted by TxAmp140and an Antenna141.

In some exemplary embodiments, 1SpSeq112and 2SpSeq122used, in the spreading process, by First-Spreader110and Second-Spreader120respectively, employ complex spreading-sequences; such as bi-phase spreading-sequence; polyphase spreading-sequence; and any combination thereof, or the like.

It will be noted that in some exemplary embodiments, 1SpSeq112and 2SpSeq122are identical. Thus, both First-Spreader110and Second-Spreader120can utilize the same spreading sequence in any given spreading process.

In some exemplary embodiments, Second-Spreader120can re-transmit a plurality of identical information replicas encapsulated in SS2123signal for improving Signal-to-Noise-Ratio (SNR) on the receiver end.

Reference is now made toFIG.1B, showing a schematic block diagram of a receiver utilizing a cascaded de-spread-spectrum system, in accordance with some exemplary embodiments of the disclosed subject matter.

FIG.1Bdepicts a receiver's cascaded de-spread-spectrum system implemented in a Receiver (Rx)102of the present disclosure. Rx102is a wireless receiver, designed to receive RF signals, having very high BW, and extract (decode) information, originated at the input signal of a transmitter, such as Data-In-Signal111of Tx101, ofFIG.1A.

The Rx102is adapted for decoding (correlating) high chip rate signals for the purpose of extracting information originated in an input signal, such as Data-in Signal111ofFIG.1A. The Rx102can be comprised of a Second-De-spreader170and a First-De-spreader180, which is connected in series to Second-De-spreader170egress.

Additionally, or alternatively, Rx102can also comprise an RF Receiver Amplifier (RxAmp)150coupled by an Antenna151adapted to receive an RFin signal and amplify it to an RF Received-Doubly-Spread-Spectrum-Signal (RF-RSS2-Signal)152. In addition, Rx102can further comprise a Frequency-Converter160and a Carrier-Generator161adapted to convert the RF-RSS2-Signal152into a Received-Doubly-Spread-Spectrum-Signal (RSS2-Signal)162.

In some exemplary embodiments, Second-De-spreader170and First-De-spreader180are configured to de-spread RSS2-Signal162for extracting information originating from a spread-spectrum transmitter, such as Tx101ofFIG.1A. De-spreading RSS2-Signal162can comprise multiplying RSS2-Signal162, by a Second-De-Spreading-Sequence (2DSpSeq)171with Second-De-spreader170for yielding an Extracted-First-Spread-Spectrum-Signal (ESS1-Signal)172. Followed by multiplying ESS1-Signal172, by a First-De-Spreading-Sequence (1DSpSeq)181with First-De-spreader180for yielding a Data-Out-Signal182, i.e., reconstructed information originated in Tx101, ofFIG.1A.

It will be noted that first and second de-spreading-sequences of Rx102are associated with corresponding spreading-sequences, i.e., first and second spreading-sequences, of the Tx101. In some exemplary embodiments, the de-spreading-sequences of the receiver are complex-conjugates of the spreading-sequences of the transmitter, i.e., 1DSpSeq181and 2DSpSeq171are complex-conjugates of 1SpSeq112and 2SpSeq122ofFIG.1A, respectively. It will also be noted that the de-spreading process of Second-De-spreader170and First-De-spreader180utilizes 2DSpSeq171and 1DSpSeq181, respectively, for correlating RSS2-Signal162and ESS1-Signal172with the transmission. In some exemplary embodiments, correlating RSS2-Signal162with 2DSpSeq171can be performed for yielding a correlated signal from which the ESS1-Signal172is created. Additionally, Second-De-spreader170can be used for sampling the correlated signal within a correlation pulse width.

In some exemplary embodiments, Second-De-spreader170and a First-De-spreader180can be electronically implemented using DSSS technique for decoding RSS2-Signal162and ESS1-Signal172respectively.

In some exemplary embodiments, 2DSpSeq171and 1DSpSeq181used in the de-spreading process, by Second-De-spreader170and First-De-spreader180respectively, employ general complex de-spreading-sequences; such as bi-phase de-spreading-sequence; polyphase de-spreading-sequence; and any combination thereof, or the like.

It will be noted that in some exemplary embodiments, 1DSpSeq181and 2DSpSeq171are identical. Thus, both First-De-spreader180and Second-De-spreader170can utilize the same de-spreading sequence in any given de-spreading process.

In some exemplary embodiments, Second-De-spreader170can comprise a digital matched filter; a noncoherent-integrator; a peak (threshold) detector; a Phase-Locked-Loop (PLL), configured to assemble (extract) ESS1-signal out of RSS2-Signal162. In some exemplary embodiments, RSS2-Signal162can be probed at a rate of W*G1*G2*K Hertz [Hz]. Thus 1/(W*G1*G2*K) seconds defines one probing time-shift (probing-cycle) out of a plurality of time-shifts in which RSS2-Signal162is probed. Where W is the bit rate, and K is the number of probs per chip. In some exemplary embodiments, the digital matched filter can be configured to generate correlation pulses by means of calculating a sum of multiplications of 2DSpSeq171by RSS2-Signal162for each probing time-shift. The noncoherent-integrator can be configured to perform a plurality of noncoherent integrations (typically, the number of noncoherent integrations can be G2*K) for probing time-shifts. The integration can be performed on probs separated by 1/(W*G1) seconds. Thereby performing the noncoherent integration for time-shifts that can accommodate a peak of the correlation pulse. Consequently, the peak detector searches for an outcome of an integration out of the plurality of integrations, that has the highest value outcome. Consequently, the PLL operating at the period of the correlation pulse (1/(W*G1) seconds), can be configured to lock on the peak detector output, thereby determining a synchronization area within boundaries of the correlation pulse.

In some exemplary embodiments, assembling the ESS1-signal comprises: at least one probing per chip of the RSS2-signal for each time-shift; generating the correlation pulse by calculating a sum of multiplications of 2DSpSeq171by the probing's outcome of each time-shift; performing a plurality of noncoherent integrations of the probing's outcome of each time-shift; searching for a highest value outcome of the noncoherent integrations; determining a synchronization area within boundaries of the correlation pulse.

In some exemplary embodiments, the digital-matched filter output is probed according to the PLL output. These probes can be defined as a correlated signal, i.e., ESS1-Signal172.

As an example, assuming that G1=G2=20 db of Tx101and a detection of Data-Out-Signal182prefers SNR of 10 db. Thus, the SNR of RSS2-Signal162can be 10−40=−30 dB and then, the Second-De-spreader170increases the SNR by 20 db to −10 db. Assuming the correlation peak detection, after noncoherent integration, have a high detection probability of 0.9 and a false detection probability of 10−6, then the required noncoherent integration gain will be 23 db to increase the SNR of the noncoherent integration result to 13 db. For the SNR of minus-infinity, the noncoherent integration gain is √{square root over (N)} where N is the number of sums. It can be determined that for an SNR of −10 db the noncoherent integration gain is N0.63, and therefore, to obtain a gain of 23 dB or a factor of 200, the number of sums can be about 4500.

In some exemplary embodiments, First-De-spreader180comprises a digital matched filter (not shown) and a noise-riding-threshold-detector (not shown). Similarly, the digital matched filter of First-De-spreader180can be configured to generate correlation pulses by means of calculating a sum of multiplications of 1DSpSeq181by ESS1-Signal172for each sampling time-shift, typically 1/(W*G1) seconds. While the noise-riding-threshold-detector acts as a filter for seeking and extracting the correlation peaks.

Additionally, or alternatively, the Rx102can utilize a serial search technique for determining optimal sampling timing of the correlation pulses. In some exemplary embodiments, Second-De-spreader170is configured to execute serial search and obtain a feedback from First-De-spreader180for each time-shift in the serial search until First-De-spreader180flags that the current time-shift provides samples of the correlation pulses that are adequate for further processing by the First-De-spreader180.

The synchronization of Second-De-spreader170can require additional synchronization time beyond the synchronization time of First-De-spreader180. Thus, in some exemplary embodiments, an additional synchronization sequence can be added, in accordance with the SNR for the detection of Data-Out-Signal182.

As an example, for packet transmission, additional time can be needed for the Second-De-spreader170to complete its synchronization, namely, sampling the exact time of the correlation pulse before First-De-spreader180starts its usual synchronization. In some exemplary embodiments, additional transmission time can be allocated before First-De-spreader180receives ESS1-Signal172on which it can be synchronized.

Additionally, or alternatively, additional time can be added to the transmitted signal, which allows for synchronization of the First-De-spreader180. The additional time doesn't affect the transmission, and it can also be acceptable for continuous transmission (non-packet transmission).

It will be noted that RSS2-Signal162is characterized by its very low spectral density across a very wide bandwidth, e.g., BW162′. While after de-spreading RSS2-Signal162by Second-De-spreader170the outcome of ESS1-Signal172has higher spectral density over a narrower bandwidth, e.g., BW172′. Likewise, after de-spreading ESS1-Signal172, by First-De-spreader180, the outcome Data-Out-Signal182has even higher spectral density over an even narrower bandwidth, e.g., BW182′. It will be appreciated that the product of G2 (PG of Second-De-spreader170) by G1 (PG of First-De-spreader180) significantly increases the spectral energy over a very narrow bandwidth.

In some exemplary embodiments, the Rx102can be provided as an add-on device, configured to receive RF-RSS2-Signal152from a transceiver and demodulate it to RSS2-Signal162. This can be followed by a two-step sequential de-spreading, first by Second-De-spreader170followed by First-De-spreader180for extracting the data represented by Data-Out-Signal182. Additionally, or alternatively, Data-Out-Signal182can be routed back to the transceiver for further processing.

In some exemplary embodiments, the Rx102can be provided as an add-on device, configured to receive (from a transceiver) a demodulated signal, i.e., RSS2-Signal162, and then conduct the two-step sequential de-spreading process using Second-De-spreader170followed by First-De-spreader180for extracting the data represented by Data-Out-Signal182. Additionally, or alternatively, Data-Out-Signal182can be routed back to the transceiver for further processing.

In some exemplary embodiments, the Rx102can be provided as an add-on device, configured to obtain RSS2-Signal162from a transceiver and execute a de-spreading process using Second-De-spreader170for assembling the ESS1-Signal172. This can be followed by routing the ESS1-Signal172back to the transceiver for completing the extracting process. Additionally, or alternatively, such add-on device can be configured to receive RSS2-RF-Signal152and demodulate it to RSS2-Signal162.

In some exemplary embodiments of the disclosed subject matter, Tx101(ofFIG.1A); Rx102; and combination thereof can be implemented and integrated into a wideband communication system/device.

In some exemplary embodiments, the Rx102of the wideband communication system of the present disclosure, is configured to perform a wireless communication receiving method. In some exemplary embodiments, the receiving method comprising: obtaining RSS2-Signal162, either from Frequency-Converter160or from an external transceiver, and de-spreading it with Second-De-spreader170, to ESS1-Signal172. Followed by, de-spreading the ESS1-Signal172with First-De-spreader180, to Data-Out-Signal182.

In some exemplary embodiments, Frequency-Converter160obtains an RF-RSS2-Signal152from RxAmp150and utilizes Carrier-Generator161for demodulating RF-RSS2-Signal152into RSS2-Signal162.

In some exemplary embodiments, Second-De-spreader170can be configured to obtain (receive) RSS2-Signal162that comprise a plurality of identical information replicas encapsulated in RSS2-Signal162. Additionally, or alternatively, Second-De-spreader170can be also be configured to extract the plurality of information replicas encapsulated in the RSS2-Signal162for adjusting the Rx102to improve an SNR of Data-Out-Signal182.

Reference is now made toFIG.2, showing a schematic block diagram of a transmitter utilizing another cascaded spread-spectrum system, in accordance with some exemplary embodiments of the disclosed subject matter.

FIG.2depicts a transmitter's cascaded spread-spectrum system implemented in a Transmitter (Tx)200of the present disclosure. Tx200is a wireless transmitter designed to encode information originating from the input signal of Tx200. Tx200is also designed to transmit signals having very wide BW, e.g., 10 Giga Hz. Tx200, can also be adapted for encoding high bitrate data signals.

In some exemplary embodiments, Tx200can comprise an Electronic-Spreader220(first-spreader); a Processor210; an Optical-Spreader230(second-spreader); a Frequency Converter240; and a Transmission-Amplifier (TxAmp)250coupled by an Antenna251.

In some exemplary embodiments, Electronic-Spreader220multiplies a Data-In-Signal221, comprising information to be transmitted, by a 1SpSeq211, thereby producing an SS1-Signal222. It will be noted that 1SpSeq211has higher chip rate than Data-In-Signal221bit rate.

Optical-Spreader230can be configured to multiply SS1-Signal222by a 2SpSeq212, for generating a SS2-Signal237. It will be noted that the bandwidth of SS2-Signal237, e.g., BW237′, is much greater than the bandwidth of SS1-Signal222, e.g., BW222′.

In some exemplary embodiments, Tx200can utilize Frequency Converter240for modulating SS2-Signal237with a Carrier-Signal213to an RF-SS2-Signal241(RFout) in order to broadcast it by TxAmp250and antenna251.

It will be noted that Data-In-Signal221is characterized by high spectral density at a narrow bandwidth, e.g., BW221′. Spreading Data-In-Signal221, by Electronic-Spreader220, yields SS1-Signal222, that is lowered in spectral density over a wider bandwidth, e.g., BW222′. Likewise, spreading SS1-Signal222, by Optical-Spreader230, yields SS2-Signal237, that is further lowered in spectral density over an even wider bandwidth, e.g., BW237′.

It will be appreciated that the product of G1 (i.e., PG of Electronic-Spreader220) by G2 (i.e., PG of Optical-Spreader230) significantly lowers the spectral energy over a very wide bandwidth. Thereby, making the transmission: harder to detect and intercept; less interfering with other channels, and less vulnerable to jamming.

In some exemplary embodiments, Tx200can comprise a Processor210that can be configured to control and or generate 1SpSeq211; 2SpSeq212; Carrier-Signal213; light pulses, by means of an Optical-generator231; and any combination thereof, or the like. Thus, it will be appreciated that by controlling 1SpSeq211, 2SpSeq212, and the light pulses, Processor210can determine the processing gain, i.e., G1 and G2, as well as the BW of SS2-Signal237.

Additionally, or alternatively, Processor210can be utilized to tune, with Carrier-Signal213, the modulating frequency of Frequency Converter240, thereby controlling Tx200broadcast frequency, i.e., RF-SS2-Signal241.

In some exemplary embodiments, Tx200can utilize Processor210to perform methods such as depicted inFIG.4. Processor210can be also utilized to perform computations needed by Tx200or any of its subcomponents. In some exemplary embodiments of the disclosed subject matter, Processor210can comprise an Input Output (I/O) module (not shown). The I/O module can be utilized as an interface to communicate information and instructions between Processor210and an external computer; other transmitters; and any combination thereof, or the like.

In some exemplary embodiments, Processor210can comprise a memory module (not shown). The memory module can be comprised of volatile and/or non-volatile memories, based on technologies such as semiconductor, magnetic, optical, flash, a combination thereof, or the like. The memory module can retain program code operative to cause Processor210to perform acts associated with any of the steps shown inFIG.4. In some exemplary embodiments, the memory module (not shown) of Processor210can be used to retain encoding information; data representations of a plurality of different spreading-sequences; and a combination thereof, or the like.

It will be noted that Processor210can be an integral component of Tx200. Additionally, or alternatively, Processor210can be equipped within an adjacent transceiver, which is configured to provide the Tx200with signals, such as 1SpSeq211; 2SpSeq212; and Carrier-Signal213.

In some exemplary embodiments, Tx200can be provided as an add-on device, configured to obtain at its input (i.e., Data-In-Signal221) an RF-out signal (of a transceiver), and then generate SS1-Signal222followed by SS2-Signal237, which will be modulated and transmitted as RF-SS2-Signal241. Additionally, or alternatively, RF-SS2-Signal241can be routed back to the transceiver for transmission.

In some exemplary embodiments, Optical-Spreader230can be comprised of an Optical-generator231; an Optical-Modulator232; Fourier Transform optics (FT-Optics)233; a Spatial Light Modulator (SLM)234; an Inverse-Fourier-Transform-Optics (IFT-Optics)235; and an Optical to Electrical Converter (O2E-Converter)236.

Optical-generator231can be an optical pulse (flash of light) generator configured to emit periodic light pulses that can be emitted, for example by a Laser based optical-generator, in a range of picoseconds. In some exemplary embodiments, the pulse width (duty-cycle) is approximately ten to thousand times smaller than the cycle of the pulse. It will also be noted that Processor210can be used to control the optical modulation of Optical-Modulator232by means of Optical-generator231e.g., by controlling the pulse width and cycle of the Laser based optical-generator, such as Optical-generator231.

Optical-Modulator232can be a Mach-Zehnder modulator or any similar type of electro-optical device having an interferometric structure made from a material with a strong electro-optic effect, such as Lithium Niobate (LiNbO3); Gallium Arsenide (GaAs); Indium Phosphide (InP); and any combination thereof, or the like. In some exemplary embodiments, applying an electric field, i.e., SS1-Signal222, to Optical-Modulator232input changes optical path lengths resulting in phase modulation of light entering, by Optical-generator231, the Optical-Modulator232optical input. In some exemplary embodiments, the Optical-Modulator232can be viewed as a modulator or as a multiplier configured to convert SS1-Signal222to a time-domain-optical-signal.

FT-Optics233can be comprised of a grating and one or more Fourier lenses, configured as an optical-signal processing component. In some exemplary embodiments, FT-Optics233can be utilized for performing a time to spatial frequency conversion. Viz. converting the time-domain-optical-signal to a frequency-domain-optical-signal.

In some exemplary embodiments, SLM234is an electro-optical component, based for example on liquid crystal technology, that spatially varies (modulates) a light beam by controlling its transparency. SLM234can modulate light beam intensity and light beam phase simultaneously. In some exemplary embodiments, SLM234can be utilized as spatial light modulator (encoder) for encoding spectrum of optical signals at its entrance (input) in accordance with a preregistered spreading-sequence.

It will be noted that SLM234of Tx200can be configured as an SLM-encoder utilized to encode the frequency-domain-optical-signal.

In some exemplary embodiments, the encoding involves scrambling the spectrum of SLM234input-signal through complex multiplication of the frequency components of the SLM's234input signal by a spreading-sequence. For example, the spreading-sequence can be a general complex spreading-sequence; a bi-phase spreading-sequence (e.g., Barker codes, m-sequences, and the like); a polyphase spreading-sequence (e.g., Frank codes, P4-codes, and the like); and any combination thereof, or the like.

In some exemplary embodiments, the time-domain-optical-signal passes through FT-Optics233that comprises a grating and a lens. The time-domain-optical-signal (collimated light) is diffracted by the grating into a plurality of spectral components that are collected and focused by the lens. At the focal plane of the lens, the plurality of spectral components of the optical-signal are linearly spatially separated. It will be noted that SLM234is positioned at the focal plane of the lens where these spatially separated spectral components (of the optical-signal) are passing (traversing) through at least one row of elements (pixels) of SLM234which contains the elements of a distinct spreading-sequence, thereby encoding the spectral components by the corresponding elements of the distinct spreading-sequence. For example, with a binary spreading-sequence for bits equal to 1 the phases of the corresponding pixels of SLM234are set to π radians, and for bits equal to 0 the phases are set to 0 radians, thereby shifting the phase of the corresponding spectral component by π or 0 radians respectively. Additionally, or alternatively, the amplitude of the spectral components can be controlled by setting the amplitude of the corresponding element of the spreading-sequence, thereby controlling the gain of the spectral components of the optical-signal.

IFT-Optics235can be comprised of one or more Fourier lenses and a grating, configured as optical-signal processing components. In some exemplary embodiments, IFT-Optics235can be utilized for performing spatial frequency to time conversion of its input optical-signal. Hence reassembling the different encoded spectral components into a single collimated output beam in the time-domain, which will be the basis of doubly spread spectrum signal.

O2E-Converter236can be a wide-band converter designed to perform optical to electrical conversion of optical-signals to measurable electrical signals. In some exemplary embodiments, the O2E-Converter236can be a bi-directional converter; hence it can be used as electrical to optical converter as well. It will be noted that the O2E-Converter236used in the present disclosure can be rated for sub-nanoseconds duration signals.

In some exemplary embodiments, optical pulses generated by Optical-generator231can be used for sampling SS1-Signal222(in the time-domain), which consequently yields a time-domain SS1-optical-signal. The time-domain SS1-optical-signal can be mathematically viewed as a multiplication of SS1-Signal222by the optical pulses (of Optical-generator231) in the time-domain. In some exemplary embodiments, the time-domain SS1-optical-signal traverses through FT-Optics233in order to convert it to the frequency-domain, thereby yielding a frequency-domain-optical-signal.

In some exemplary embodiments, the frequency-domain-optical-signal that egress the FT-Optics233enters SLM234, where it is encoded in accordance with second-spreading-sequence for yielding a frequency-domain-encoded-optical-signal. It will be appreciated that SLM234(SLM-encoder) can comprise at least one, pre-registered, second-spreading-sequence, provided via 2SpSeq212.

Additionally, or alternatively, encoding the frequency-domain-optical-signal with 2SpSeq212can comprise pre-emphasizing the frequency-domain-optical-signal. Pre-emphasizing the frequency-domain-optical-signal can be implemented by adjusting the elements of pre-registered 2SpSeq212in the SLM234for higher gain intensities and/or predetermined phases for spatial frequency segments related to higher frequencies, in order to compensate for increased attenuation at high frequencies parts of the signal.

It will be appreciated that 2SpSeq212is used for providing SLM234with one or a plurality of spreading-sequences, which will be utilized for encoding the optically-modulated input of SLM234. It will be noted that SLM234can be a matrix having columns (first dimension) and rows (second dimension), wherein each row contains elements of a single sequence.

It will be noted that in some exemplary embodiments, 1SpSeq211and 2SpSeq212are identical. Thus, both Electronic-Spreader220and Optical-Spreader230can utilize the same spreading sequence in any given spreading process.

In some exemplary embodiments, the spreading-sequences can be registered to SLM234, and altered from time to time. It will be noted that the registration time can take up to a few milliseconds.

Additionally, or alternatively, the plurality spreading-sequences can be registered to SLM234at the same time, utilizing a second dimension of the SLM234, wherein each sequence of the plurality of sequences can be instantly selected, as desired, by Processor210. The selection of the sequence is performed for example by an optical device (such as a mirror or an electro-optic beam deflection device, or the like) which deflects the light beam to the appropriate area in the SLM in the second dimension. Alternatively, a bank of Optical Heterodyne Detectors will be placed to receive all possible results associated with all spreading-sequences and appropriate detector output will be selected.

In some exemplary embodiments, the frequency-domain-encoded-optical-signal, i.e., output of the SLM-encoder, can be converted by IFT-Optics235to yield a time-domain-encoded-optical-signal. Subsequently, time-domain-encoded-optical-signal can be converted by O2E-Converter236for yielding the SS2-Signal237.

In some exemplary embodiments, Tx200can be provided as an add-on device, configured to receive (from a transceiver) a first-spread-spectrum signal, such as SS1-Signal222, and then generate, with Optical-Spreader230, the SS2-Signal237, which can be either modulated to RF-SS2-Signal241and transmitted by TxAmp250, or routed back to the transceiver for transmission. That is to say that in some exemplary embodiments, such add-on device can only incorporate Optical-Spreader230and connections to the transceiver.

In some exemplary embodiments of the disclosed subject matter, Tx200can be implemented and integrated into a wideband communication system/device.

In some exemplary embodiments, Optical-Spreader230can re-transmit a plurality of identical information replicas encapsulated in SS2237signal for improving SNR on the receiver end.

Referring now toFIG.3, there is shown a schematic block diagram of a receiver utilizing another cascaded de-spread-spectrum system, in accordance with some exemplary embodiments of the disclosed subject matter.

FIG.3depicts a receiver's cascaded spread-spectrum system implemented in a Receiver (Rx)300of the present disclosure. In some exemplary embodiments, Rx300can be a wireless receiver, designed to receive RF signals and reconstruct (decode) information, originated at the input signal of a transmitter, such as Data-In-Signal221of Tx200, ofFIG.2.

In some exemplary embodiments, Rx300can comprise an Optical-Correlator330(second de-spreader) and an Electronic-De-Spreader320(first de-spreader) that is connected via a Filter332in series to Optical-Correlator330egress.

Additionally, or alternatively, Rx300can further comprise an RF input amplifier (RxAmp)350coupled by Antenna351that are adapted to amplify received signals into an RF-RSS2-Signal352; and a Frequency-Converter340used for demodulating RF-RSS2-Signal352, to an RSS2-Signal341.

In some exemplary embodiments, a process of information extraction from RSS2-Signal341can comprise correlating RSS2-Signal341with a 2DSpSeq312using Optical-Correlator330, which yields an ESS1-Signal333, followed by Multiplying ESS1-Signal333, by a 1DSpSeq311, using Electronic-De-Spreader320, which yields a Data-Signal-Out321.

It will be noted that first and second de-spreading-sequences of Rx300are associated with a corresponding spreading-sequences, i.e., first and second spreading-sequences, of the Tx200. In some exemplary embodiments, the de-spreading-sequences of Rx300are a complex-conjugate of the spreading-sequences of Tx200, i.e., 1DSpSeq311and 2DSpSeq312are respectively equal to the complex-conjugate of 1SpSeq211and 2SpSeq212ofFIG.2. Additionally, or alternatively, 1DSpSeq311and 2DSpSeq312are respectively equal to the complex-conjugate of 1SpSeq112and 2SpSeq122ofFIG.1A.

It will be noted that RSS2-Signal341is characterized by its very low spectral density across a very wide bandwidth, e.g., BW341′. While after correlating and filtering the RSS2-Signal341, by Optical-Correlator330and Filter332, the outcome of ESS1-Signal333, has higher spectral density over a narrower bandwidth, e.g., BW333′. Likewise, after de-spreading ESS1-Signal333, by Electronic-De-Spreader320, the outcome, Data-Out-Signal321has even higher spectral density over an even narrower bandwidth, e.g., BW321′.

In some exemplary embodiments, Rx300can comprise a Processor310that can be configured to control and generate 1DSpSeq311; 2DSpSeq312; Carrier-Signal313and any combination thereof, or the like. Thus, it will be appreciated that by controlling 1DSpSeq311and 2DSpSeq312Processor310controls the correlation process in which the data is reconstructed (extracted). Additionally, or alternatively, Processor310can be utilized to tune, with Carrier-Signal313, the demodulating frequency of the Frequency Converter340, thereby controlling Rx300reception frequency, i.e., RSS2-Signal341.

In some exemplary embodiments, Rx300can utilize Processor310to perform methods such as depicted inFIG.5. Processor310can be also utilized to perform computations needed by Rx300or any of its subcomponents. In some exemplary embodiments of the disclosed subject matter, Processor310can comprise an I/O module (not shown). The I/O module can be utilized as an interface to communicate information and instructions between Processor310and an external computer; other transmitters, such as Tx200; and any combination thereof, or the like.

In some exemplary embodiments, Processor310can comprise a memory module (not shown). The memory module can be comprised of volatile and/or non-volatile memories, based on technologies such as semiconductor, magnetic, optical, flash, a combination thereof, or the like. The memory module (not shown) can retain program code operative to cause Processor310to perform acts associated with any of the steps shown inFIG.5. In some exemplary embodiments, the memory module (not shown) of Processor310can be used to retain encoding information; data representations of a plurality of different de-spreading-sequences; and a combination thereof, or the like.

It will be noted that Processor310can be an integral component of Rx300. Additionally, or alternatively, Processor310can be equipped within an adjacent transceiver, which can be configured to provide the Rx300with signals, such as 1DSpSeq311; 2DSpSeq312; and Carrier-Signal313.

In some exemplary embodiments, Optical-Correlator330can be comprised of: Optical-generator231; Optical-Modulator232; FT-Optics233; SLM234; IFT-Optics235; O2E-Converter236; a Noncoherent-Integrator335; and a Pulse Detector336.

In some exemplary embodiments, Optical-generator231, of Optical-Correlator330, can be an optical-generator, such as a continuous wave Laser based optical-generator.

Optical-Modulator232can be a Mach-Zehnder modulator or any similar type of electro-optical device having an interferometric structure made from a material with a strong electro-optic effect, such as LiNbO3; GaAs; InP; or any combination thereof, or the like. In some exemplary embodiments, applying an electric field to Optical-Modulator232input, i.e., with RSS2-Signal341, changes optical path lengths resulting in phase modulation of light entering Optical-Modulator232from Optical-generator231, thereby converting the RSS2-Signal341to a time-domain optical-signal. In some exemplary embodiments, the output of Optical-Modulator232can be viewed as a modulator or as a multiplier. It will also be noted that Processor310can be used to control the optical modulation of Optical-Modulator232by means of Optical-generator231.

FT-Optics233can be comprised of a grating and one or more Fourier lenses configured as an optical-signal processing component. In some exemplary embodiments, FT-Optics233can be utilized for performing a time-to-spatial frequency conversion of the time-domain optical-signal into a frequency-domain-optical-signal.

In some exemplary embodiments, SLM234; is an electro-optical component, based for example on liquid crystal technology, that spatially varies (modulate) a light beam by controlling its transparency. SLM234can modulate light beam intensity; light beam phase and simultaneously a combination thereof. In some exemplary embodiments, SLM234, of Rx300, can be configured as an SLM-decoder utilized to decode the encoded spectrum at its input, e.g., frequency-domain-optical-signal. It will be noted that SLM234of Rx300, i.e., the SLM-decoder is utilized to decode the frequency-domain-optical-signal to a frequency-domain-decoded-optical-signal.

In some exemplary embodiments, the time-domain-optical-signal (collimated light) passes through the grating and lenses of FT-Optics233signal where it is diffracted into a plurality of spectral components that are collected and focused by a lens. At the focal plane of the lens, the spectral components of the optical-signal are linearly spatially separated. It will be noted that SLM234is positioned at the focal plane of the lens where these spatially separated spectral components, of the time-domain-optical-signal, are passing through at least one row of elements (pixels) of the SLM234. In some exemplary embodiments, the elements correspond to a distinct spreading-sequence, thereby decoding the spectral components by the corresponding elements of the distinct de-spreading-sequence. For example, with a binary spreading-sequence for bits equal to 1 the phases of the corresponding pixels of SLM234are set to π radians, and for bits equal to 0 the phases are set to 0 radians, thereby shifting the phase of the corresponding spectral component by π or 0 radians respectively. Additionally, or alternatively, an amplitude of each spectral component can be controlled by setting the amplitude of the corresponding element of the spreading-sequence, thereby controlling the gain of each spectral component of the optical-signal.

It will be appreciated that SLM234, of Rx300, is utilized for decoding, using at least one 2DSSeq312to decode the frequency-domain-optical-signal into a frequency-domain-decoded-optical-signal. In some exemplary embodiments, SLM234can be utilized for filtering interference from the frequency-domain-optical-signal.

IFT-Optics235can be comprised of one or more Fourier lenses and a grating configured as optical-signal processing components. In some exemplary embodiments, IFT-Optics235can be utilized for performing spatial frequency to time conversion of its input optical-signal by reassembling the different decoded spectral components into a single collimated output beam in the time-domain, thereby transforming a frequency-domain-decoded-optical-signal to a time-domain-decoded-optical-signal.

O2E-Converter236can be a wide-band converter designed to convert optical-signals to measurable electrical signals. In some exemplary embodiments, the O2E-Converter236can be an Optical Heterodyne Detector that converts an optical-signal to an electrical signal while preserving the phase. It will be noted that O2E-Converter236of the present disclosure can be rated for nanoseconds duration signals for performing optical to electrical conversion of an optically sampled time-domain-correlated-optical-signal (to be described in detail further below) to a correlated electrical signal, i.e., ESS1333.

In some exemplary embodiments, Noncoherent-Integrator335can be configured to optically probe the outcoming time-domain decoded optical-signal from IFT-Optics235, and to derive a plurality of integrations (typically, the number of integrations is G2*K), each shifted by a time-shift with respect to the previous probing. In some exemplary embodiments, the outcoming time-domain decoded optical-signal can be optically probed at a rate of W*G1*G2*K Hz. [Hz]. Thus 1/(W*G1*G2*K) seconds defines one optical-probing time-shift (cycle) out of a plurality of time-shifts in which time-domain decoded optical-signal can be optically probed. Where W is the bit rate of 2DSSeq312, and K is an optical-probing factor. The noncoherent integration can be performed on probes separated by 1/(W*G1) seconds, thereby performing the noncoherent integration for time-shifts that can accommodate the peak of the correlation pulse. Pulse Detector336can be configured to optically sample the outcoming time-domain-decoded-optical-signal from IFT-Optics235. In some exemplary embodiments, Pulse Detector336can comprise a peak (threshold) detector (not shown) used to detect pulses generated by Noncoherent-Integrator335; and a PLL, operating at the period of the correlation pulse (1/(W*G1) seconds). Therefore, the PLL can be used to lock on the period of the detected noncoherently integrated pulses thus providing Pulse Detector336an indication for selecting the optically sampled correlation pulses at the outcoming time-domain-decoded-optical-signal, thereby determining a synchronization area within boundaries of the correlation pulse, which enables optically-sampling the time-domain-decoded-optical-signal within the correlation pulse width for yielding the optically sampled-time-domain-correlated-optical-signal.

Additionally, or alternatively, the Rx300can utilize a serial search technique for determining an optimal optical sampling timing of the correlation pulses. In some exemplary embodiments, Optical correlator330can be configured to execute a serial search and obtain a feedback from Electronic De-spreader320for each time-shift in the serial search until Electronic De-spreader320flags that the current time-shift provides samples of the correlation pulses that are adequate for further processing by the Electronic De-spreader320.

In some exemplary embodiments, Optical correlator330can extend its synchronization time, in accordance with the SNR, beyond synchronization time needed by Electronic De-spreader320.

As an example, for packet transmission, additional time can be needed for the Optical correlator330to complete its synchronization, namely, sampling the exact time of the correlation pulse before Electronic De-spreader320starts its usual synchronization. In some exemplary embodiments, additional synchronization transmission time can be allocated before Electronic De-spreader320receives the ESS1-Signal333on which it will be synchronized.

Additionally, or alternatively, additional time can be added to the transmitted signal, which allows for synchronization of the Electronic De-spreader320. The additional time doesn't affect the reception, and this can also be acceptable for continuous reception (non-packet transmission).

In some exemplary embodiments, the optical-signal generated by Optical-generator231is used for modulating RSS2-Signal341(in the time-domain), which consequently yields a time-domain optical-signal. The time-domain optical-signal can be mathematically viewed as a multiplication of RSS2-Signal341by the optical-signal (of Optical-generator231) in the time-domain. In some exemplary embodiments, the time-domain optical-signal traverses through FT-Optics233in order to be converted to the frequency-domain, thereby yielding the frequency-domain-optical-signal. In some exemplary embodiments, the frequency-domain-optical-signal that egress the FT-Optics233enters SLM234, where its spectrum shall be decoded in accordance with 2DSpSeq312that was pre-registered in SLM234and thereby yielding a frequency-domain-decoded-optical-signal.

It will be appreciated that 2DSpSeq312is used for providing SLM234with at least one de-spreading-sequence utilized for decoding the frequency-domain-optical-signal. In some exemplary embodiments, the de-spreading-sequences can be registered to SLM234, and altered from time to time. It will be noted that the registration time can take up to a few milliseconds. Additionally, or alternatively, the plurality of de-spreading-sequence can be registered to SLM234at the same time, utilizing a second dimension of the SLM234, wherein, consequently, each sequence of the plurality of sequences can be instantly selected, as desired, by Processor310. The selection of the sequence is performed for example by an optical device (such as a mirror, or an electro-optic beam deflection device, or the like) which deflects the light beam to the appropriate area in the SLM in the second dimension. Alternatively, a bank of Optical Heterodyne Detectors will be placed to receive results associated with the sequences and appropriate detector output will be selected.

In some exemplary embodiments, the frequency-domain-decoded-optical-signal, i.e., SLM234outcome, can be converted by IFT-Optics235to a time-domain-decoded-optical-signal.

In some exemplary embodiments, Pulse Detector336and Noncoherent-Integrator335mutually produce the correlation pulses that are used to decode (reconstruct) the original first spread-spectrum from the time-domain-decoded-optical-signal. In some exemplary embodiments, Pulse Detector336yields a First-Extracted-Spread-Spectrum (ESS1)-optical-signal followed by converting it by O2E-Converter236to electrical representation, i.e., ESS1-Signal333, which can undergo analog filtration by Filter332.

In some exemplary embodiments, the Rx300can be provided as an add-on device, configured to receive RF-RSS2-Signal352from a transceiver and demodulate it to RSS2-Signal341. This can be followed by a two-step sequential de-spreading, first by Optical-Correlator330followed by Electronic-De-Spreader320for reconstructing (extracting) the data that is represented by Data-Out-Signal321. Additionally, or alternatively, Data-Out-Signal321can be routed back to the transceiver for further processing.

It will be noted that in some exemplary embodiments, 1DSpSeq311and 2DSpSeq312are equal. Thus, both Electronic-De-Spreader320and Optical-Correlator330can utilize the same de-spreading sequence in any given de-spreading process.

In some exemplary embodiments, the Rx300can be provided as an add-on device, configured to receive (from a transceiver) a demodulated signal, i.e., RSS2-Signal341, and then generate with Optical-Correlator330and Filter332the ESS1-Signal333, which can be routed back to the transceiver for completing the next de-spreading step and the reception process. That is to say that, in some exemplary embodiments, such add-on device can incorporate Optical Correlator330and connections to the transceiver.

Additionally, or alternatively, the add-on device depicted above can comprise an Electronic-De-Spreader320configured to process the ESS1-Signal333for reconstructing the data that is represented by Data-Out-Signal321. In turn, Data-Out-Signal321can be routed back to the transceiver for further processing.

In some exemplary embodiments of the disclosed subject matter, Rx300can be implemented and integrated into a wideband communication system/device.

In some exemplary embodiments, Rx300can be configured to obtain (receive) RSS2-Signal341that comprise a plurality of identical information replicas encapsulated in RSS2-Signal341. Additionally, or alternatively, Rx300can be also configured to extract the plurality of information replicas encapsulated in the RSS2-Signal for the purposes of adjusting the Rx300, leading for improving the SNR of the RSS2-Signal.

Reference is now made toFIG.4showing a flowchart diagram of a transmitting method for the transmitter ofFIG.2, in accordance with some exemplary embodiments of the disclosed subject matter.

In step401, an SS1-Signal can be obtained. In some exemplary embodiments, the SS1-Signal (such as SS1-Signal113ofFIG.1A; SS1-Signal222, ofFIG.2; and an external SS1-Signal, generated by an external transceiver) can be obtained by a second spreader (such as Optical-Spreader230ofFIG.2, and Second-Spreader120ofFIG.1A).

In step402, the SS1-Signal can be converted to the optical domain. In some exemplary embodiments, Optical-generator231, ofFIG.2, and Optical-Modulator232, ofFIG.2, are mutually used for sampling and optically modulating SS1-Signal in order to produce a SS1-Optical-Signal.

In step403, the SS1-Optical-Signal can be transformed to the frequency-domain-optical-signal. In some exemplary embodiments, FT-Optics233, ofFIG.2, can be used for transforming SS1-Optical-Signal that is characterized by a plurality of spectral components.

In step404, the frequency-domain-optical-signal can be encoded using an SLM-encoder. In some exemplary embodiments, SLM234, ofFIG.2that is configured as SLM-encoder encodes frequency-domain-optical-signal in accordance with a spread sequence that was pre-registered in SLM234, ofFIG.2, by means of 2SpSeq212, ofFIG.2, thereby yielding a frequency-domain-encoded-optical-signal.

In step405, the frequency-domain-encoded-optical-signal can be transformed to time-domain-encoded-optical-signal. In some exemplary embodiments, IFT-Optics235, ofFIG.2, can be used for transforming the frequency-domain-encoded-optical-signal to the time-domain.

In step406, the time-domain-encoded-optical-signal can be converted to an electrical signal. In some exemplary embodiments, O2E-Converter236, ofFIG.2, can be utilized for converting the time-domain-encoded-optical-signal to SS2-electrical signal, such as SS2-Signal237, ofFIG.2.

In step407the time-domain SS2-Signal, such as SS2-Signal237(ofFIG.2) and SS2-Signal123(ofFIG.1A) can be modulated and transmitted. In some exemplary embodiments, a frequency converter, such as Frequency Converter240, ofFIG.2; and the Frequency Converter130, ofFIG.1A, can be utilized (respectively) for modulating SS2-Signal237into RF-SS2-Signal241(ofFIG.2) and SS2-Signal123into RF-SS2-Signal132(ofFIG.1A). Additionally, RF-SS2-Signal241(ofFIG.2) and RF-SS2-Signal132(ofFIG.1A) can be, respectively, transmitted by TxAmp250(ofFIG.2) and TxAmp140(ofFIG.1A).

It is to be further noted that, with reference toFIG.4, some of the blocks can be integrated into a consolidated block or can be broken down to a few blocks and/or other blocks can be added. Furthermore, in some cases, the blocks can be performed in a different order than described herein. It is to be further noted that some of the blocks are optional. It will be also noted that whilst the flow diagram is described also with reference to the system elements that realizes them, this is by no means binding, and the blocks can be performed by elements other than those described herein.

Referring now toFIG.5, there is shown a flowchart diagram of a receiving method for the receiver ofFIG.3, in accordance with some exemplary embodiments of the disclosed subject matter.

In step501, an RF-RSS2-Signal can be received and demodulated. In some exemplary embodiments, the RF-RSS2-Signal, such as RF-RSS2-Signal352(ofFIG.3) and RF-RSS2-Signal152(ofFIG.1B) can be received and amplified by RxAmp350(ofFIG.3) and RxAmp150(ofFIG.1B), respectively. In some exemplary embodiments, the RF-RSS2-Signal can be demodulated to an RSS2-Signal by Frequency Converter240(ofFIG.3), or Frequency-Converter160, (ofFIG.1B), which are used to demodulate RF-RSS2-Signal352(ofFIG.3) and RF-RSS2-Signal152(ofFIG.1B) into RSS2-Signal341(ofFIG.3) and RSS2-Signal162(ofFIG.1B), respectively.

In step502, the RSS2-Signal can be converted. In some exemplary embodiments, Optical-generator231and Optical-Modulator232(ofFIG.3) can be mutually used for optically modulating the SS2-Signal to an optical-signal.

In step503, the optical-signal can be transformed to the frequency-domain. In some exemplary embodiments, FT-Optics233, (ofFIG.3) can be used for transforming the optical-signal from the time-domain to a frequency-domain-optical-signal.

In step504, the frequency-domain-optical-signal can be decoded using a Spatial Light Modulator (SLM). In some exemplary embodiments, an SLM, such as SLM234(ofFIG.3), decodes the frequency-domain-optical-signal, in accordance with de-spreading-sequence by 2DSpSeq312. In some exemplary embodiments, the de-spreading-sequences can be pre-registered in SLM234, ofFIG.3, by means of 2DSpSeq312, ofFIG.3, thereby yielding a frequency-domain-decoded-optical-signal. Additionally, or alternatively, the RSS2-Signal can be decoded using DSSS decoding.

In step505, frequency-domain-decoded-optical-signal can be converted to the time-domain. In some exemplary embodiments, IFT-Optics235(ofFIG.3) can be used for converting the frequency-domain-decoded-optical-signal to time-domain-decoded-optical-signal. In some exemplary embodiments, Pulse Detector336and Noncoherent-Integrator335(ofFIG.3) are configured to mutually produce correlation pulses utilized to extract an original first-spread-spectrum signal. In some exemplary embodiments, Pulse Detector336(ofFIG.3) yields an optically sampled time-domain correlated optical-signal.

In step506, the optically sampled time-domain correlated optical-signal can be converted to a correlated electrical signal. In some exemplary embodiments, O2E-Converter236(ofFIG.3) can be utilized for converting the optically sampled time-domain correlated optical-signal to a correlated electrical signal. Additionally, or alternatively, the correlated electrical signal can be filtered by an analog filter, such as Filter332(ofFIG.3), thereby yielding a first extracted spread spectrum (ESS1) electrical signal such as ESS1-Signal333(ofFIG.3).

In step507, the time-domain correlated electrical signal, i.e., a ESS1 electrical signal can be de-spread by a supplementary correlator to a baseband signal. In some exemplary embodiments, the ESS1 electrical signal can undergo a second stage de-spreading process with a supplementary correlator, such as First-De-spreader180(ofFIG.1B); and Electronic-De-Spreader320(ofFIG.3) that yield Data-Out-Signal182(ofFIG.1B) and Data-Signal-Out321(ofFIG.3), respectively.

It is to be further noted that, with reference toFIG.5, some of the blocks can be integrated into a consolidated block or can be broken down to a few blocks and/or other blocks can be added. Furthermore, in some cases, the blocks can be performed in a different order than described herein. It is to be further noted that some of the blocks are optional. It will be also noted that whilst the flow diagram is described also with reference to the system elements that realizes them, this is by no means binding, and the blocks can be performed by elements other than those described herein.

It is to be understood that the presently disclosed subject matter is not limited in its application to the details set forth in the description contained herein or illustrated in the drawings. The presently disclosed subject matter is capable of other embodiments and of being practiced and carried out in various ways. Hence, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception upon which this disclosure is based can readily be utilized as a basis for designing other structures, methods, and systems for carrying out the several purposes of the present presently disclosed subject matter.

It will also be understood that the system according to the presently disclosed subject matter can be implemented, at least partly, as a suitably programmed computer. Likewise, the presently disclosed subject matter contemplates a computer program being readable by a computer for executing the disclosed method. The presently disclosed subject matter further contemplates a machine-readable memory tangibly embodying a program of instructions executable by the machine for executing the disclosed method.