Patent Description:
Intensity modulation and direction detection (IM/DD) is widely used in short-reach transmission systems. One type of IM/DD includes phase shift keying (PSK) in which the phase of the carrier wave is modulated with a signal to transmit data. Implementing different types of PSK on IM/DD systems is difficult because of noise, signal loss, and phase detection issues. Examples of devices using ternary modulation are provided in <CIT>, <CIT>, <CIT> and <CIT>.

The following description includes discussion of figures having illustrations given by way of example of implementations of embodiments of the disclosure. The drawings should be understood by way of example, and not by way of limitation. As used herein, references to one or more "embodiments" are to be understood as describing a particular feature, structure, or characteristic included in at least one implementation of the presently taught subject matter. Thus, phrases such as "in one embodiment" or "in an alternate embodiment" appearing herein describe various embodiments and implementations of the presently taught subject matter, and do not necessarily all refer to the same embodiment. However, they are also not necessarily mutually exclusive. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure ("FIG. ") number in which that element or act is first introduced.

Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as discussing other potential embodiments or implementations of the various concepts presented herein. An overview of embodiments of the disclosure is provided below, followed by a more detailed description with reference to the drawings.

In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide an understanding of various embodiments of the presently taught subject matter. It will be evident, however, to those skilled in the art, that embodiments of the presently taught subject matter may be practiced without these specific details. In general, well-known instruction instances, structures, and techniques are not necessarily shown in detail.

Generally, intensity modulation / direct detection is common in some short-reach transmission systems. One approach includes on-off keying (OOK), which is among the oldest modulation formats used in optical IM/DD systems that still remains popular due to its low implementation cost. However, the <NUM>-bit carrying OOK format cannot meet the ever-increasing bandwidth requirement in today's information society. <NUM>-level pause amplitude modulation (PAM4), which carries <NUM> bits per symbol, has been proposed and commercially implemented in intra/inter-data center networks. However, lots of optics manufacturers use a wait-and-see approach about the mass production of PAM4 transceivers, especially in the application of beyond <NUM> reach. Accordingly, OOK cannot meet modern bandwidth requirements, coherent solution approaches are still too expensive to be commercially deployed in inter/intra-date center networks, and PAM4 solutions are not easily upgradable to coherent solutions in the future and thus may become out of date and impractical as technology evolves.

To this end, a ternary phase shift keying (TPSK) based optical communication system can be implemented to transmit and receive data in TPSK format. In some example embodiments, the binary data is converted into TPSK symbols using a distribution matcher to generate TPSK sequence data. The TPSK data can be mapped to a non-TPSK format that is easy to transmit over existing systems (e.g., existing binary systems). For example, the TPSK data is mapped to QPSK data using a phase mapping. Further, forward error correction can be implemented by converting the symbol data into binary data for forward error correction, then converting it back into the symbol data for transmission.

In some example embodiments, the data is transmitted over a single mode fiber to a receiver, which can use various detection schemes, such as direct or coherent detection, to detect the signal. The received signal data can be sampled at transient time between the symbol segments using an analog-to-digital converter and channel equalizer. The sampled QPSK symbol data can be converted into binary data for forward error correction decoded, and then mapped back TPSK data using the QPSK to TPSK phase mapping. Further, the receiver implements an inverse distribution matching module to recover and store the binary message data.

The TPSK-based optical communication system provides benefits over traditional OOK because it carries more bits per symbol than traditional OOK. Further, the TPSK-based optical communication system is easier to upgrade to coherent solutions than PAM4 while still being compatible with a traditional OOK-based system. Further, users implementing the system can select coherent detection and/or direct detection as per their requirements, so the proposed solution can meet the diverse market requirements. Additionally, the interoperable transmitter of the TPSK system can be readily adapted for use with newer detection schemes.

<FIG> shows an example architecture <NUM> of a phase shift keying transmitter and receiver, according to some example embodiments. In the transmitter <NUM>, binary data can be modulated using phase modulation of an optical carrier (e.g., light). The modulated signal is then boosted using an amplifier (e.g., EDFA) and transmitted to the receiver over a transmission architecture <NUM>, such as a network, in open air as radio waves, or an optical medium such as single mode fiber <NUM> (SMF) with several amplifiers. In the receiver <NUM>, the received optical signal is recovered and translated back into the binary data for output.

<FIG> show example constellation and eyediagrams, according to some example embodiments. <FIG> displays a quaternary constellation diagram and <FIG> displays a quaternary eyediagram that corresponds to the quaternary constellation diagram of <FIG> displays a ternary constellation diagram and <FIG> displays a ternary eyediagram that corresponds to the ternary constellation diagram of <FIG>.

A constellation diagram (e.g., <FIG>) is a representation of a signal modulated by a digital modulation scheme (e.g., quadrature amplitudebased modulation, quaternary phase-shift keying, ternary phase shift keying, and so on). Constellation diagrams display the signal as a two-dimensional XY-plane scatter diagram in the complex plane at symbol sampling instants. The angle of a point, measured counterclockwise from the horizontal axis, represents the phase shift of the carrier wave from a reference phase. The distance of a point from the origin represents a measure of the amplitude or power of the signal.

An eyediagram (e.g., <FIG>) is an example signal detection display (e.g., oscilloscope display) in which a signal from a receiver is repetitively sampled and applied to the vertical input, while the data rate is used to trigger the horizontal sweep.

In the constellation diagram of <FIG>, the four symbols (e.g., modes, states) of the quaternary scheme include "<NUM>", "<NUM>", "<NUM>", and "<NUM>", each of which corresponds to a phase and amplitude for the given symbol. As discussed, if quaternary modulation is implemented, phase loss can occur and some transitions between the symbols will become indistinguishable from one another.

For example, in <FIG>, the transition from symbol "<NUM>" to "<NUM>" corresponds to a curve <NUM> in the eyediagram of <FIG>, which is distinguishable from the other curves in <FIG>. Further, again with reference to <FIG>, the transition from "<NUM>" to "<NUM>" corresponds to a curve <NUM> in the eyediagram of <FIG>, which is again distinguishable from the other curves in <FIG>.

However, when using direct detection, some quaternary scheme transitions will be degenerate in that they are indistinguishable from one another and have approximately the same transition curve in the detected displays (e.g., eyediagram of <FIG>). In particular, for example, in <FIG>, the transition from "<NUM>" to "<NUM>" and the transition from "<NUM>" to "<NUM>" both result in curve <NUM> in the eyediagram of <FIG>. Thus, as the two are indistinguishable, systemic errors will occur in of the QPSK data when transmitted and received (e.g., using direct detection).

To this end, a ternary phase shift keying scheme can be implemented to avoid indistinguishable phases and errors. In particular, as illustrated in the constellation diagram in <FIG>, a ternary phase shift keying scheme includes three symbols (modes) including "<NUM>", "<NUM>", and "<NUM>"; however, no mode is implemented in the bottom left had quadrant (as denoted by the non-solid circle <NUM> in <FIG>), thereby avoiding degenerate phases.

For example, in <FIG>, the transition from symbol "<NUM>" to "<NUM>" corresponds to a curve <NUM> in the eyediagram of <FIG>, which is distinguishable from the other curves in <FIG>. Further, again with reference to <FIG>, the transition from "<NUM>" to "<NUM>" corresponds to curve <NUM> in the eyediagram of <FIG>, and the transition from "<NUM>" to <NUM>" (in <FIG>) corresponds to curve <NUM> (in <FIG>). As illustrated in <FIG>, no transitions overlap and thus they can be distinguished (e.g., when transitions are detected using direct detection), and thereby properly decoded without systemic error.

<FIG> shows a mapping architecture <NUM> for converting TPSK to a non-TPSK format (e.g., QPSK, binary PSK, additional higher order PSK formats) for transmission, according to some example embodiments. As discussed with reference to <FIG> above, implementing TPSK can avoid errors by using curves that are distinguishable by the receiver detector (e.g., in direct detection, a fast photo diode). To facilitate transmission of TPSK-encoded data over existing networks (e.g., binary networks configured to transmit data in <NUM>'s and <NUM>'s), the TPSK data is converted to QPSK data for transmission and then converted back into TPSK at the receiver, in accordance with some example embodiments.

The example displayed in <FIG> shows example mapping from TPSK to QPSK for transmission, where the reverse mapping process can then be used at the receiver to convert received QPSK data back into TPSK data for further processing (e.g., sampling, ternary based decoding).

As illustrated, the eyediagram <NUM> displays a ternary encoding scheme for TPSK symbols. In the example, the TPSK symbols - <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> - create curve mappings on the diagram <NUM>, where "<NUM>" corresponds to no change and no turning (e.g., can be displayed as a loop back to the same symbol), "<NUM>" corresponds to turning <NUM> degrees clockwise, and "<NUM>" corresponds to turning <NUM> degrees clockwise.

In the illustrated example, starting from the top left symbol ("START HERE"), the first TPSK symbol is "<NUM>," (from the TPSK symbols) which is a <NUM>-degree turn to the top-right point (corresponding to mapping arrow <NUM>). The second TPSK symbol is "<NUM>", which is a repeat symbol back to the top-right point (corresponding to mapping arrow <NUM>). The third TPSK symbol is "<NUM>," which is a <NUM>-degree turn to the bottom left symbol (corresponding to mapping arrow <NUM>). The third symbol is another <NUM>, which is another <NUM>-degree turn back to the top right symbol (corresponding to mapping arrow <NUM>). The fourth symbol is a "<NUM>," which is a <NUM>-degree turn from the top right symbol to the bottom right symbol (corresponding to mapping arrow <NUM>). The fifth symbol is another "<NUM>," which is a <NUM>-degree turn from the bottom right to bottom left symbol (corresponding to mapping arrow <NUM>).

To generate the QPSK symbols, the mapping <NUM> from the TPSK symbol sequence is then applied to the QPSK constellation diagram <NUM>, in which the top left symbol is "<NUM>", the top right symbol is "<NUM>", the bottom right symbol is "<NUM>" and the bottom left symbol is "<NUM>". That is, in particular, the mapping <NUM> starts from the top left symbol so the QPSK symbols start with "<NUM>", followed by "<NUM>", followed by a repeat "<NUM>" due to the looped curve <NUM>, and so on.

In the example of <FIG>, the starting point is the top left symbol, which generates a starting "<NUM>" in the QPSK symbol sequence. However, it is not necessary to always start from the top-left symbol; any point can be used. For the decoding purpose (e.g., at the receiver), there can be an indicator (e.g., stored in memory or decoding instructions) to show where the symbols start from. Therefore, if starting from <NUM>, the QPSK symbols will lead with a <NUM>; if starting from <NUM>, the QPSK symbols will lead with a <NUM>, and so on.

Additionally, the TPSK symbols can be converted to other formats, other than QPSK (e.g., binary PSK (BPSK)), for transmission across a network, according to some example embodiments. That is, for example, a higher order PSK format having <NUM> states or modes can be mapped to (from TPSK) using different phase shifts per TPSK symbol. For instance, while the above example for QPSK uses no turn for "<NUM>", <NUM> degree turn for "<NUM>", and <NUM> degree turn for "<NUM>", the amount of turn per TPSK signal can be customized to work for higher order PSK schemes (e.g., an <NUM> mode scheme) by turning by different amounts per TPSK symbol (e.g., <NUM> digress for "<NUM>", <NUM> degree turn for "<NUM>" and <NUM> degree turn "<NUM>" of the TPSK signals), such that the mapping created maps TPSK to different modes of the higher order PSK scheme, or lower order scheme (e.g., BPSK), according to some example embodiments.

<FIG> and <FIG> show example sampling configurations, according to some example embodiments. Generally, QPSK symbols can only be detected by coherent detection, where symbol sampling occurs at the center of symbol time as non-center sampling locations incur signal-to-noise ratio issues. However, sampling at center symbol time using the TPSK scheme can result in loss in information. For example, in the sampling graph <NUM> of <FIG>, the center sampled point <NUM> may miss the data to be detected. In contrast, as shown in <FIG>, in sampling graph <NUM>, the sampling of ternary data is implemented at transient time (e.g., transition points between symbols), and each signal can be sampled for the TPSK data as illustrated by sampling point <NUM>.

<FIG> shows an example transmitter <NUM> and receiver <NUM>, according to some example embodiments. In the example of <FIG>, the components of the transmitter <NUM> and receiver can be implemented using software (applications, non-transitory or transitory instructions stored in or conveyed to memory), hardware (e.g., servers, switches), electrical devices (e.g., chips, control circuitry, an Field Programmable Gate Array), optical devices (e.g., lasers, fiber cables, photodiodes) and combinations thereof. In the transmitter <NUM>, one or more light sources, such as laser <NUM>, can generate binary data <NUM>. In some example embodiments, the binary data <NUM> is not generated by the light sources, but is rather received from an external source not depicted in <FIG>, such as a fiber from another component, or may be identified as binary data stored in memory and ready for transmission via the transmitter <NUM>.

The binary data <NUM> is input into a distribution matcher <NUM> (e.g., a constant composition distribution (CCDM) based distribution matcher), which is configured to efficiently convert binary data to a symbol sequence following any entropy, including for example a ternary symbol scheme (e.g., three symbols: <NUM>, <NUM>, <NUM>). The distribution matcher <NUM> (DM) encodes a binary input data sequence into a sequence of symbols (codewords), with desired target probability distribution. In some example embodiments, the distribution matcher <NUM> uses a CCDM version of distribution matching to map the binary data <NUM> to <NUM>, <NUM>, <NUM> ternary symbols, where each symbol is generated with equal probability (<NUM>/<NUM>). In some example embodiments, it is not necessary to generate each of the three symbols with equal likelihood. For example, the distribution matcher <NUM> can implement an exponential distribution to generate a more power-efficient modulation format, according to some example embodiments. The set of the output codewords constitutes a codebook (or code) of the DM <NUM>. Further, constant-composition DM (CCDM) uses arithmetic coding to efficiently encode data into codewords from a constant-composition (CC) codebook, which can be implemented to decode the symbols back into binary data using inverse distribution matcher <NUM> in the receiver <NUM>.

The TPSK data from the distribution matcher <NUM> is then input into the TPSK-QPSK converter <NUM>, which converts the TPSK symbol data into QPSK symbol data, as discussed above with reference to <FIG>.

The QPSK symbols output by the TPSK-QPSK converter <NUM> are then converted into bits using a bit labeling module <NUM>. For example, with reference to the constellation diagram <NUM> in <FIG>, if the QPSK symbol is "<NUM>," it is converted into binary "<NUM>" by the bit labeling module <NUM>.

The bit data is then input into forward error correction (FEC) coding module <NUM> for error correction processing. Generally, forward error correction is a technique used for controlling errors in data transmission over unreliable or noisy communication channels. In FEC, the transmitter encodes the message in a redundant way, most often by using an error-correcting code (ECC). The redundancy allows the receiver to detect a number of errors that may occur anywhere in the message (e.g., errors accumulated while in transit), and often to correct these errors without re-transmission.

FEC enables the receiver the ability to correct errors without needing a reverse channel to request re-transmission of data. In some example embodiments, non-binary FEC is implemented; however, non-binary FEC is complex and can be difficult to implement. In the illustrated embodiment, the QPSK data has already been converted into binary data and thus a binary FEC scheme can be beneficially implemented by the transmitter <NUM> and receiver <NUM>. The FEC coding module <NUM> outputs binary data, which is then input into binary-to-symbol (B2S) mapping module <NUM> for conversion back into QPSK symbols.

The data is then input into a pre-compiler CD <NUM> for processing, followed by a digital-to-analog converter <NUM> (DAC), which then converts the data into analog data, which is then transmitted via I/Q modulator <NUM> using laser <NUM>.

The data is transmitted from the transmitter <NUM> to the receiver <NUM> over transmission architecture <NUM>, such as a single mode fiber (SMF) and one or more amplifiers (e.g., erbium-doped fiber amplifier (EDFA)) to boost the signal along the way.

At the receiver <NUM>, a detector <NUM> receives the data from the transmission architecture <NUM> (e.g., as analog signal). Notably, the detector <NUM> can be a direct detection (DD)-based detector or coherent detection-based detector, either of which will work with transmitter <NUM> without requiring a matching transmitter type, as discussed in further detail below with reference to <FIG>.

The detector <NUM> outputs the analog data into an analog-to-digital converter (ADC) <NUM>, which initially samples the analog data, and then the optimal transient points are obtained by re-sampling algorithms using the channel equalizer <NUM> to generate QPSK data. The data is then converted from QPSK symbols into binary data by symbol-to-binary (S2B) mapping module <NUM> for binary-based error correction using the FEC decoding module <NUM>. The FEC decoding module <NUM> performs binary-based error correction decoding, and then outputs the binary data into S2B mapping module <NUM>. The binary data is then converted into QPSK symbols by the S2B mapping module <NUM> and then converted into TPSK symbols using QPSK-TPSK converter <NUM>. For example, the QPSK-TPSK converter <NUM> uses the reverse of the process discussed with reference to <FIG> above (e.g., mapping QPSK curves to TPSK data). The TPSK symbols are output by the QPSK-TPSK converter <NUM>, and then converted from ternary symbols into binary data using an inverse distribution matcher <NUM> discussed above, which then outputs binary data <NUM> for further process or storage (e.g., in memory).

One benefit of the TPSK scheme of <FIG> is that the transmitter (e.g., transmitter <NUM>) is interoperable with different types of receivers. This enables a single transmitter to function with the current state of the art (e.g., direct detection systems) and advances to such systems, such as coherent detection systems, which rolled out while requiring minimal or no changes to the TPSK transmitters. <FIG> show examples of interoperable transmitter and receiver configurations, according to some example embodiments.

<FIG> shows an example direct detection (DD) TPSK communication architecture <NUM>, according to some example embodiments. In the illustrated example, the TPSK transceiver <NUM> and TPSK transceiver <NUM> both include a TPSK transmitter (Tx), such as transmitter <NUM>. Further, each of TPSK transceivers <NUM> and <NUM> includes direct detection-based receivers (D-Rx). For example, both of the both of TPSK transceivers <NUM> and <NUM> include a direct detection version of detector <NUM> in <FIG>.

<FIG> shows an example hybrid TPSK communication architecture <NUM>, according to some example embodiments. In the illustrated example, the TPSK transceiver <NUM> and TPSK transceiver <NUM> both include a TPSK transmitter (Tx), such as transmitter <NUM>. However, the transceivers <NUM>, <NUM> have different types of receiver modules. For example, the transceiver <NUM> may have upgraded to a coherent detection-based receiver (C-Rx), while the transceiver <NUM> retains its detection-based receiver (D-Rx). However, due to the interoperable TPSK architecture (e.g., transmitter <NUM> of <FIG>), the transceiver <NUM> does not need to modify its transmitter to work with the coherent detection-based receiver of transceiver <NUM> and can use its same transmitter with any other TPSK-based receiver, whether it is a direct detection-based receiver or coherent detection-based receiver.

<FIG> shows an example coherent detection based TPSK communication architecture <NUM> in which the present invention may be deployed. In the illustrated example, the TPSK transceiver <NUM> and TPSK transceiver <NUM> both include a TPSK transmitter (Tx), such as transmitter <NUM>. Further, the transceivers <NUM>, <NUM> have the same type of receivers, i.e., coherent-based receivers (e.g., C-Rx). For example, both transceivers <NUM>, <NUM> have upgraded to coherent detection-based detectors in their receiver modules. Further, while coherent detection-based receivers are discussed as an example of an upgraded receiver, the architecture of TPSK transmitter (e.g., transmitter <NUM>) removes the emphasis on receiver type, thereby allowing future receiver types to be integrated into the TPSK architecture to allow future upgradeability.

<FIG> shows an example TPSK data center architecture <NUM> in which the present invention may be deployed. As illustrated, data center <NUM> comprises TPSK transceiver <NUM>, TPSK transceiver <NUM>, and TPSK transceiver <NUM>. Data center <NUM> is a separate data center (e.g., a data center at a different geographic location) and comprises TPSK transceiver <NUM>, TPSK transceiver <NUM>, and TPSK transceiver <NUM>. Each data center <NUM>, <NUM> can use its TPSK transceivers to communicate data with other transceivers, each of which may have different receiver types (e.g., direct detection, coherent detection, etc.) but can still implement the same interoperable TPSK transmitter. For example, TPSK transceiver <NUM> can use its TPSK transmitter (Tx <NUM>) to send TPSK data (e.g., TPSK data in non-TPSK format) to the coherent detection-based receiver (C-Rx <NUM>) in transceiver <NUM>. Similarly, TPSK transceiver <NUM> uses its interoperable TPSK transmitter (Tx <NUM>) to send data to a direct detection-based receiver (D-Rx <NUM>) in the TPSK transceiver <NUM>, which is located in the same data center <NUM>; further, TPSK transceiver <NUM> can also use its same TPSK transmitter (Tx <NUM>) to send an inter-data center link communication to transceiver <NUM>, which receives the data using a coherent detection-based receiver (C-Rx <NUM>). Thus, as illustrated, not all receivers need be of the same exact type; different receiver types can be used, and they can be upgraded at different points in time and still receive the TPSK data in an efficient and robust manner.

<FIG> shows a flow diagram of an example method <NUM> for implementing a TPSK transmitter (e.g., transmitter <NUM>), according to some example embodiments. At operation <NUM>, the TPSK transmitter <NUM> generates binary data. For example, the TPSK transmitter <NUM> generates binary data using a light source. According to some alternative embodiments, the data may be identified instead of generated at operation <NUM>. That is, for example, the binary data has already been generated and is stored in memory of the transmitter ready for encoding and transmission.

At operation <NUM>, the TPSK transmitter <NUM> generates TPSK data. For example, the TPSK transmitter <NUM> uses a distribution matcher to convert the binary data into ternary symbols, e.g., <NUM>, <NUM>, <NUM>, using an equal distribution likelihood.

At operation <NUM>, the TPSK transmitter <NUM> converts the TPSK data to transmission format. For example, the TPSK transmitter <NUM> maps the TPSK symbol sequence into a non-TPSK format, such as a QPSK symbol sequence, as discussed above. Additionally, and in accordance with some example embodiments, the generated QPSK symbols are then converted into bits for FEC coding, and then converted back into QPSK for transmission.

At operation <NUM>, the TPSK transmitter <NUM> transmits non-TPSK data to its destination. For example, the TPSK transmitter <NUM> transmits the data in the non-TPSK format to the receiver <NUM> over a single mode fiber boosted by one or more amplifiers.

<FIG> shows a flow diagram of an example method <NUM> for implementing a TPSK-based receiver, according to some example embodiments.

At operation <NUM>, the TPSK receiver <NUM> receives data in the non-TPSK format. For example, the TPSK receiver <NUM> uses direct detection-based system to receive the data. Alternatively, the TPSK receiver <NUM> uses a coherent detection-based receiver or other types of receiver detectors, such as antennas, to receive the data.

At operation <NUM>, the TPSK receiver <NUM> samples the received data at transient time. For example, the data is received as an analog signal, which is then first sampled by an analog-to-digital converter (ADC). Then the optimal transient points are obtained by implementing re-sampling in the channel equalization module in the receiver.

At operation <NUM>, the TPSK receiver <NUM> converts the sampled non-TPSK data to TPSK data. For example, the non-TPSK sampled data can be data in the QPSK format. The QPSK data is then converted into binary data to undergo binary FEC decoding and is then converted back into the QPSK data. After binary-based error correction, the QPSK data is then converted into TPSK data using a phase mapping as discussed in <FIG> above. For example, the QPSK data sequence curves are mapped to a TPSK constellation diagram to generate the TPSK data.

At operation <NUM>, the TPSK receiver <NUM> converts the TPSK data into binary data. For example, the TPSK receiver <NUM> implements an inverse distribution matcher using the same codebook as the distribution matcher in the transmitter <NUM> to convert the TPSK symbols into binary data.

<FIG> illustrates a diagrammatic representation of a machine <NUM> in which the present invention may be deployed, the form of a computer system within which a set of instructions may be executed for causing the machine to perform any one or more of the methodologies discussed herein, according to an example embodiment. Specifically, <FIG> shows a diagrammatic representation of the machine <NUM> in the example form of a computer system, within which instructions <NUM> (e.g., software, a program, an application, an applet, an app, or other executable code) for causing the machine <NUM> to perform any one or more of the methodologies discussed herein may be executed. For example, the instructions <NUM> may cause the machine <NUM> to execute the method <NUM> of <FIG> (as a transmitter) and/or execute the <NUM> of <FIG> (as a receiver). Additionally, or alternatively, the instructions <NUM> may implement the transmitter <NUM> or the receiver <NUM> in <FIG>, and so forth. The instructions <NUM> transform the general, non-programmed machine <NUM> into a particular machine <NUM> programmed to carry out the described and illustrated functions in the manner described. In alternative embodiments, the machine <NUM> operates as a standalone device or may be coupled (e.g., networked) to other machines. In a networked deployment, the machine <NUM> may operate in the capacity of a server machine or a client machine in a server-client network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine <NUM> may comprise, but not be limited to, a server computer, a client computer, a personal computer (PC), a tablet computer, a laptop computer, a netbook, a set-top box (STB), a PDA, an entertainment media system, a cellular telephone, a smart phone, a mobile device, a wearable device (e.g., a smart watch), a smart home device (e.g., a smart appliance), other smart devices, a web appliance, a network router, a network switch, a network bridge, or any machine capable of executing the instructions <NUM>, sequentially or otherwise, that specify actions to be taken by the machine <NUM>. Further, while only a single machine <NUM> is illustrated, the term "machine" shall also be taken to include a collection of machines <NUM> that individually or jointly execute the instructions <NUM> to perform any one or more of the methodologies discussed herein.

The machine <NUM> may include processors <NUM>, memory <NUM>, and I/O components <NUM>, which may be configured to communicate with each other such as via a bus <NUM>. In an example embodiment, the processors <NUM> (e.g., a Central Processing Unit (CPU), a Reduced Instruction Set Computing (RISC) processor, a Complex Instruction Set Computing (CISC) processor, a Graphics Processing Unit (GPU), a Digital Signal Processor (DSP), an ASIC, a RadioFrequency Integrated Circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, a processor <NUM> and a processor <NUM> that may execute the instructions <NUM>. The term "processor" is intended to include multi-core processors that may comprise two or more independent processors (sometimes referred to as "cores") that may execute instructions contemporaneously. Although <FIG> shows multiple processors <NUM>, the machine <NUM> may include a single processor with a single core, a single processor with multiple cores (e.g., a multi-core processor), multiple processors with a single core, multiple processors with multiples cores, or any combination thereof.

The memory <NUM> may include a main memory <NUM>, a static memory <NUM>, and a storage unit <NUM>, both accessible to the processors <NUM> such as via the bus <NUM>. The instructions <NUM> may also reside, completely or partially, within the main memory <NUM>, within the static memory <NUM>, within the storage unit <NUM>, within at least one of the processors <NUM> (e.g., within the processor's cache memory), or any suitable combination thereof, during execution thereof by the machine <NUM>.

The I/O components <NUM> may include a wide variety of components to receive input, provide output, produce output, transmit information, exchange information, capture measurements, and so on. The specific I/O components <NUM> that are included in a particular machine will depend on the type of machine. For example, portable machines such as mobile phones will likely include a touch input device or other such input mechanisms, while a headless server machine will likely not include such a touch input device. It will be appreciated that the I/O components <NUM> may include many other components that are not shown in <FIG>. The I/O components <NUM> are grouped according to functionality merely for simplifying the following discussion and the grouping is in no way limiting. In various example embodiments, the I/O components <NUM> may include output components <NUM> and input components <NUM>. The output components <NUM> may include visual components (e.g., a display such as a plasma display panel (PDP), a light emitting diode (LED) display, a liquid crystal display (LCD), a projector, or a cathode ray tube (CRT)), acoustic components (e.g., speakers), haptic components (e.g., a vibratory motor, resistance mechanisms), other signal generators, and so forth. The input components <NUM> may include alphanumeric input components (e.g., a keyboard, a touch screen configured to receive alphanumeric input, a photo-optical keyboard, or other alphanumeric input components), point-based input components (e.g., a mouse, a touchpad, a trackball, a joystick, a motion sensor, or another pointing instrument), tactile input components (e.g., a physical button, a touch screen that provides location and/or force of touches or touch gestures, or other tactile input components), audio input components (e.g., a microphone), and the like.

In further example embodiments, the I/O components <NUM> may include biometric components <NUM>, motion components <NUM>, environmental components <NUM>, or position components <NUM>, among a wide array of other components. For example, the biometric components <NUM> may include components to detect expressions (e.g., hand expressions, facial expressions, vocal expressions, body gestures, or eye tracking), measure biosignals (e.g., blood pressure, heart rate, body temperature, perspiration, or brain waves), identify a person (e.g., voice identification, retinal identification, facial identification, fingerprint identification, or electroencephalogram-based identification), and the like. The motion components <NUM> may include acceleration sensor components (e.g., accelerometer), gravitation sensor components, rotation sensor components (e.g., gyroscope), and so forth. The environmental components <NUM> may include, for example, illumination sensor components (e.g., photometer), temperature sensor components (e.g., one or more thermometers that detect ambient temperature), humidity sensor components, pressure sensor components (e.g., barometer), acoustic sensor components (e.g., one or more microphones that detect background noise), proximity sensor components (e.g., infrared sensors that detect nearby objects), gas sensors (e.g., gas detection sensors to detection concentrations of hazardous gases for safety or to measure pollutants in the atmosphere), or other components that may provide indications, measurements, or signals corresponding to a surrounding physical environment. The position components <NUM> may include location sensor components (e.g., a GPS receiver component), altitude sensor components (e.g., altimeters or barometers that detect air pressure from which altitude may be derived), orientation sensor components (e.g., magnetometers), and the like.

Communication may be implemented using a wide variety of technologies. The I/O components <NUM> may include communication components <NUM> operable to couple the machine <NUM> to a network <NUM> or devices <NUM> via a coupling <NUM> and a coupling <NUM>, respectively. For example, the communication components <NUM> may include a network interface component or another suitable device to interface with the network <NUM>. In further examples, the communication components <NUM> may include wired communication components, wireless communication components, cellular communication components, Near Field Communication (NFC) components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components to provide communication via other modalities. The devices <NUM> may be another machine or any of a wide variety of peripheral devices (e.g., a peripheral device coupled via a USB).

The various memories (i.e., <NUM>, <NUM>, <NUM>, and/or memory of the processor(s) <NUM>) and/or storage unit <NUM> may store one or more sets of instructions and data structures (e.g., software) embodying or utilized by any one or more of the methodologies or functions described herein. These instructions (e.g., the instructions <NUM>), when executed by processor(s) <NUM>, cause various operations to implement the disclosed embodiments.

As used herein, the terms "machine-storage medium," "device-storage medium," "computer-storage medium" mean the same thing and may be used interchangeably in this disclosure. The terms refer to a single or multiple storage devices and/or media (e.g., a centralized or distributed database, and/or associated caches and servers) that store executable instructions and/or data. The terms shall accordingly be taken to include, but not be limited to, solid-state memories, and optical and magnetic media, including memory internal or external to processors. Specific examples of machine-storage media, computer-storage media and/or device-storage media include non-volatile memory, including by way of example semiconductor memory devices, e.g., erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), Field Programmable Gate Array (FPGA), and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The terms "machine-storage media," "computer-storage media," and "device-storage media" specifically exclude carrier waves, modulated data signals, and other such media, at least some of which are covered under the term "signal medium" discussed below.

In various example embodiments, one or more portions of the network <NUM> may be an ad hoc network, an intranet, an extranet, a VPN, a LAN, a WLAN, a WAN, a WWAN, the Internet, a portion of the Internet, a portion of the PSTN, a plain old telephone service (POTS) network, a cellular telephone network, a wireless network, a Wi-Fi® network, another type of network, or a combination of two or more such networks. For example, the network <NUM> or a portion of the network <NUM> may include a wireless or cellular network, and the coupling <NUM> may be a Code Division Multiple Access (CDMA) connection, a Global System for Mobile communications (GSM) connection, or another type of cellular or wireless coupling. In this example, the coupling <NUM> may implement any of a variety of types of data transfer technology, such as Single Carrier Radio Transmission Technology (1xRTT), Evolution-Data Optimized (EVDO) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for GSM Evolution (EDGE) technology, third Generation Partnership Project (3GPP) including <NUM>, fourth generation wireless (<NUM>) networks, Universal Mobile Telecommunications System (UMTS), High Speed Packet Access (HSPA), Worldwide Interoperability for Microwave Access (WiMAX), Long Term Evolution (LTE) standard, others defined by various standardsetting organizations, other long range protocols, or other data transfer technology.

The instructions <NUM> may be transmitted or received over the network <NUM> using a transmission medium via a network interface device (e.g., a network interface component included in the communication components <NUM>) and utilizing any one of a number of well-known transfer protocols (e.g., hypertext transfer protocol (HTTP)). Similarly, the instructions <NUM> may be transmitted or received using a transmission medium via the coupling <NUM> (e.g., a peer-to-peer coupling) to the devices <NUM>. The terms "transmission medium" and "signal medium" mean the same thing and may be used interchangeably in this disclosure. The terms "transmission medium" and "signal medium" shall be taken to include any intangible medium that is capable of storing, encoding, or carrying the instructions <NUM> for execution by the machine <NUM>, and includes digital or analog communications signals or other intangible media to facilitate communication of such software. Hence, the terms "transmission medium" and "signal medium" shall be taken to include any form of modulated data signal, carrier wave, and so forth. The term "modulated data signal" means a signal that has one or more of its characteristics set or changed in such a matter as to encode information in the signal.

The terms are defined to include both machine-storage media and transmission media.

Therefore, from one perspective, there has been described a ternary phase shift keying transmitter and receiver can efficiently communicate using ternary encoded data that avoids indistinguishable transition curves for each of the three modulated states in the ternary encoded data. The transmitter is interoperable and can function with different types of receivers including direct detection-based receivers and coherent detection-based receivers.

Claim 1:
A method for processing optical data using a phase shift key transmitter, the method comprising:
identifying (<NUM>) data in a binary format;
generating (<NUM>) ternary phase shift key data from the data in the binary format, the data being encoded in the ternary phase shift key data in three states;
generating (<NUM>) non-ternary phase shift key data from the ternary phase shift key data, the data being encoded in the non-ternary phase shift key data in a quantity of states other than the three states; and
transmitting (<NUM>) the non-ternary phase shift key data to a receiver as light.