Transmitters and communication systems are disclosed. In one example, a transmitter includes first to third serializers that generate first to third serial signals; a first output section configured to set a voltage of a first output terminal; a first output control circuit configured to control an operation of the first output section on the basis of the first serial signal and the second serial signal; a second output section configured to set a voltage of a second output terminal; a second output control circuit configured to control an operation of the second output section on the basis of the third serial signal and the first serial signal; a third output section configured to set a voltage of a third output terminal; and a third output control circuit configured to control an operation of the third output section on the basis of the second serial signal and the third serial signal.

A system and method for recovering encoded data from a modulated baseband signal is disclosed. Aspects and embodiments of the system and method include receiving an analog input signal representing a modulated baseband signal, counting clock cycles of a reference clock, detecting a first transition and a second transition of the analog input signal indicating a first change and a second change in the modulated baseband signal, storing a first counter value corresponding to an amount of clock cycles elapsed between the first transition and the second transition, and determining a binary-valued bit sequence corresponding to the first counter value.

Embodiments may provide a way of communicating via an electromagnetic radiator, or light source, that can be amplitude modulated such as light emitting diode (LED) lighting and receivers or detectors that can determine data from light received from the amplitude modulated electromagnetic radiator. Some embodiments may provide a method of transmitting/encoding data via modulated LED lighting and other embodiments may provide receiving/decoding data from the modulated LED lighting by means of a device with a low sampling frequency such as a relatively inexpensive camera (as might be found in a smart phone). Some embodiments are intended for indoor navigation via photogrammetry (i.e., image processing) using self-identifying LED light anchors. In many embodiments, the data signal may be communicated via the light source at amplitude modulating frequencies such that the resulting flicker is not perceivable to the human eye.

Signals transmitted on the backhaul links of a cloud radio access network may be compressed using joint compression encoding. Joint compression encoding may be performed using a successive estimation-compression architecture. Joint compression encoding may include designing preceding matrices that may be used with signal compression. Joint compression encoding may be applied to signals transmitted on the downlink of the cloud radio access network. One or more baseband signals to be delivered over the backhaul links may be jointly compressed using multivariate compression. Multivariate compression may be implemented using successive compression based on a sequence of minimum mean squared error (MMSE) estimations and per BS compression.

It is possible to improve the spectral efficiency of multi-layer multiple input multiple output (MIMO) transmissions by estimating the magnitude parameter at the receiver side, rather signaling the magnitude parameter from the transmitter to the receiver. In long term evolution (LTE) networks, the user equipment (UE) may estimate the power allocation (Pa) parameter by executing a series of steps. For example, the UE may define a single unknown variable from a received downlink MIMO signal, extend the single unknown scalar variable to a multivariate signal model for multiple channels (N), convert the multivariate signal model to a MIMO configured signal model, and then obtain the Pa parameter from the MIMO configured multivariate signal model.

A PAM-N receiver capable of adaptively adjusting threshold voltages determining a level of a received signal and a method of adaptively adjusting threshold voltages thereof are disclosed. According to the method of the present invention, the result of comparison between reference data levels and the level of data in the received signal are used to adjust the reference data levels, and the threshold voltages of a PAM-N receiver are adaptively calculated from the adjusted reference data levels, thereby reflecting transmission line conditions and Inter-Symbol Interference.

A transceiver of the present inventive concept includes a transmitter and a receiver connected by a first line and a second line, and the transmitter includes a first encoder; a second encoder; and a transmission driver. The first encoder generates a first encoded data different from a first data during a first period and the second encoder generates a second encoded data equal to a second data during the first period, the second encoder generates the second encoded data different from the second data during a second period and the first encoder generates the first encoded data equal to the first data during the second period, and the first period and the second period are arranged to alternate with each other.

A quadrature transmitter is described that comprises: a first transmitter path and a second transmitter path that are matched. Each transmitter path comprises: at least one input arranged to receive respective first or second sets of quadrature baseband signals; at least one local oscillator, LO, port configured to receive respective first and second sets of quadrature LO signals; at least one mixer stage coupled to the at least one input and configured to respectively multiply the sets of quadrature baseband signals with the respective first or second sets of quadrature LO signals to produce a respective output radio frequency, RF, signal; and a combiner configured to combine the output radio frequency signals of the first transmitter path and the second transmitter path. The first set of quadrature signals is a substantially 45° phase shifted version of the second set of quadrature signals; and the first set of quadrature LO signals is a reverse substantially 45° phase shifted version of the second set of quadrature LO signals.

A quadrature transmitter is described that comprises: a first transmitter path and a second transmitter path that are matched. Each transmitter path comprises: at least one input arranged to receive respective first or second sets of quadrature baseband signals; at least one local oscillator, LO, port configured to receive respective first and second sets of quadrature LO signals; at least one mixer stage coupled to the at least one input and configured to respectively multiply the sets of quadrature baseband signals with the respective first or second sets of quadrature LO signals to produce a respective output radio frequency, RF, signal; and a combiner configured to combine the output radio frequency signals of the first transmitter path and the second transmitter path. The first set of quadrature signals is a substantially 45° phase shifted version of the second set of quadrature signals; and the first set of quadrature LO signals is a reverse substantially 45° phase shifted version of the second set of quadrature LO signals.

Systems an methods are provided that disclose providing a positioning service for devices based on light received from one or more light sources. This light based positioning service uses light information transmitted by each light source to determine the position of the device. The positioning information can include three dimension position information in a building that can then be used to deliver services and information to a mobile device. The content delivered to a mobile device can include multimedia, text, audio, and/or pictorial information. The positioning information along with other location or positioning information can be used in providing augmented reality or location aware services. The light sources can be independent beacons that broadcast information in visible light at a rate that is undetectable by the human eye. Content can be retrieved from a server over a communications connection.