A transmission device includes: a first mapper that maps a first bit stream of a first data series to generate a first modulated symbol stream of the first data series; a second mapper that maps a second bit stream of a second data series to generate a second modulated symbol stream of the second data series; a converter that subjects the second modulated symbol stream to conversion in accordance with the first modulated symbol stream; a superposition unit that superposes the first modulated symbol stream and the second modulated symbol stream at a predetermined amplitude ratio to generate a multiplexed signal, the second modulated symbol stream having been subjected to the conversion in accordance with the first modulated symbol stream; and a transmitter that transmits the multiplexed signal.

A transmission device includes: a first mapper that maps a first bit stream of a first data series to generate a first modulated symbol stream of the first data series; a second mapper that maps a second bit stream of a second data series to generate a second modulated symbol stream of the second data series; a converter that subjects the second modulated symbol stream to conversion in accordance with the first modulated symbol stream; a superposition unit that superposes the first modulated symbol stream and the second modulated symbol stream at a predetermined amplitude ratio to generate a multiplexed signal, the second modulated symbol stream having been subjected to the conversion in accordance with the first modulated symbol stream; and a transmitter that transmits the multiplexed signal.

An apparatus including: a first transmission processing unit that generates transmission signal sequences of multiple power layers that are to be multiplexed using power allocation; and a second transmission processing unit that processes a transmission signal sequence of a power layer using an interleaver, a scrambler, or a phase coefficient corresponding to the power layer for each of one or more of the multiple power layers. The apparatus improves accuracy of decoding of a desired signal when multiplexing/multiple access is performed using power allocation.

An apparatus including: a first transmission processing unit that generates transmission signal sequences of multiple power layers that are to be multiplexed using power allocation; and a second transmission processing unit that processes a transmission signal sequence of a power layer using an interleaver, a scrambler, or a phase coefficient corresponding to the power layer for each of one or more of the multiple power layers. The apparatus improves accuracy of decoding of a desired signal when multiplexing/multiple access is performed using power allocation.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive user data and provide electrical signals based on the data; and a modulator operable to modulate the optical signal to provide optical subcarriers based on the electrical signals. A first one of the subcarriers carriers carries first TDMA encoded information and second TDMA encoded information, such that the first TDMA encoded information is indicative of a first portion of the data and is carried by the first one of the subcarriers during a first time slot, and the second TDMA encoded information is indicative of a second portion of the data and is carried by the first one of the subcarriers during a second time slot. The first TDMA encoded information is associated with a first node remote from the transmitter and the second TDMA encoded information is associated with a second node remote from the transmitter. A second one of the subcarriers carries third information that is not TDMA encoded, the third information being associated with a third node remote from the transmitter. A receiver and system also are described.

Consistent the present disclosure, a network or system is provided in which a hub or primary node may communication with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity that may be greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed that receive data carrying optical signals from and supply data carrying optical signals to the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, and optical add/drop multiplexer, for example. Consistent with an aspect of the present disclosure, optical subcarriers may be transmitted over such connections. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced. In addition, the subcarriers may be employed using multiple access techniques, such as frequency division multiplexing (FDM), code-division multiple access (CDMA), and time-division multiple access so that the primary node can communicate with a relatively large number of secondary nodes. In addition, an out-of-band control channel may be provided to carry OAM information from the primary node to the secondary nodes, as well as from the secondary nodes to the primary nodes.

Consistent the present disclosure, a network or system is provided in which a hub or primary node may communication with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity that may be greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed that receive data carrying optical signals from and supply data carrying optical signals to the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, and optical add/drop multiplexer, for example. Consistent with an aspect of the present disclosure, optical subcarriers may be transmitted over such connections. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced. In addition, the subcarriers may be employed using multiple access techniques, such as frequency division multiplexing (FDM), code-division multiple access (CDMA), and time-division multiple access so that the primary node can communicate with a relatively large number of secondary nodes. In addition, an out-of-band control channel may be provided to carry OAM information from the primary node to the secondary nodes, as well as from the secondary nodes to the primary nodes.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive data and provide a plurality of electrical signals based on the data; and a modulator operable to modulate the optical signal to provide a plurality of optical subcarriers based on the plurality of electrical signals. One of the plurality of subcarriers carries first information indicative of a first portion of the data in a first time slot and second information indicative of a second portion of the data in a second time slot. The first information is associated with a first node remote from the transmitter and the second information is associated with a second node remote from the transmitter. A receiver as well as a system also are described.

Methods and apparatus for increasing spectral efficiency in non-orthogonal multiple access (NOMA) communication, that implement receiving a signal stream from a user, splitting the signal stream into a plurality of sub-streams, applying a forward error coding (FEC) to each one of the sub-streams, and outputting a corresponding plurality of FEC encoded sub-streams. This can include modulating a corresponding carrier with each of the FEC encoded sub-streams, and combining and transmitting the corresponding plurality of modulated carrier signals. The modulated carrier signals can each carry a respective one of the FEC encoded sub-streams.

Methods and apparatus for increasing spectral efficiency in non-orthogonal multiple access (NOMA) communication, that implement receiving a signal stream from a user, splitting the signal stream into a plurality of sub-streams, applying a forward error coding (FEC) to each one of the sub-streams, and outputting a corresponding plurality of FEC encoded sub-streams. This can include modulating a corresponding carrier with each of the FEC encoded sub-streams, and combining and transmitting the corresponding plurality of modulated carrier signals. The modulated carrier signals can each carry a respective one of the FEC encoded sub-streams.