A plurality of error correction circuits corrects errors of the data transmitted through the plurality of transmission lines. A combining portion combines the plurality of transmission lines to the plurality of error correction circuits. The plurality of transmission lines includes a first transmission line, and a second transmission line having a lower transmission characteristic than the first transmission line. The plurality of error correction circuits includes a first and a second error correction circuit having lower error correction capability and power consumption than the first error correction circuit. The combining portion uses a function to combine a plurality of error correction circuits with one transmission path, combines the first transmission line with the second error correction circuit at a higher rate than the first error correction circuit, and combines the second transmission line with the first error correction circuit at a higher rate than the second error correction circuit.

Systems and methods for applying a pilot tone to multiple spectral bands are provided. An initial signal is divided into multiple spectral bands. A pilot tone is applied to each of the spectral bands, and then the signals are again combined for transmission. The pilot tones differ in some way, for example in phase or frequency.

Systems and methods providing for dynamic switching between the various waveforms on the downlink are described. Embodiments of a dynamic downlink waveform switching implementation may, for example, support utilization of one or more multiple carrier (MC) waveform (e.g., OFDMA) or other high peak to average power ratio (PAPR) waveform and one or more SC (SC) waveform (e.g., discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM)) or other low PAPR waveform. Dynamic selection of a downlink waveform may be made by an access point based upon various metrics, including relative distance to a served an access terminal and the preference of downlink waveform indicated by a served an access terminal. A downlink waveform selection indication may be signaled from the access point to the served an access terminal using downlink control information (DCI).

A transmission system for performing communication according to time division duplex (TDD), includes a relay unit configured to relay uplink signals and downlink signals in the first and second communication systems, a TDD information estimation unit configured to estimate a transmission stop period during which no uplink signal of the first communication system is transmitted, an estimation error detection unit configured to detect that the estimation of the transmission stop period is erroneous on the basis of the uplink signal or the downlink signal of the first communication system, and a bandwidth allocation unit configured to prioritize allocation of a bandwidth in the relay unit for the uplink signal of the first communication system over allocation of a bandwidth in the relay unit for the uplink signal of the second communication system if the estimation of the transmission stop period is erroneous.

Various features related to using a multi-port synchronization signal as reference for demodulating a multi-port broadcast channel are described. In an aspect, a synchronization signal, e.g., SSS, may be repurposed to serve as a demodulation reference for a downlink channel, e.g., PBCH, thereby obviating the need for a base station to send an additional reference signal for PBCH demodulation. A base station may select two or more logical antenna ports to transmit a synchronization signal, transmit the synchronization signal from the selected two or more logical antenna ports, and transmit information on the PBCH, from at least the selected two or more logical antenna ports. A UE may receive the synchronization signal from the two or more logical antenna ports at the base station, receive information on the PBCH from the at least the two or more logical antenna ports, and demodulate the information based on the received synchronization signal.

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for transmitting signals with a high data rate. In some implementations, an apparatus includes a first digital signal processor outputting first data at a first data rate. A second digital signal processor outputting second data at a second data rate. A filter circuitry receiving and up-sampling the first and second data. Additionally, the apparatus includes a combiner circuit that receives the first up-sampled data and the second up-sampled data, the combiner circuit combining the first and second up-sampled data to provide a multiplexed output, the multiplexed output having a third data rate that is greater than the first data rate or the second data rate.

Currently, wideband channel simulation/emulation is carried out through channel realizations obtained from dispersion functions dictated by communication standards, in order to perform the tests and validation of the new data communication schemes. However, the channel models available in the state of the art only consider the simulation/emulation of stationary channels with separable dispersion characteristics, allowing only the treatment of unrealistic channels. The present invention describes and details a method and apparatus for performing the channel simulation/emulation in scenarios where the channel is doubly selective, i.e., selective in time and frequency, where the simulation/emulation is of an arbitrarily long duration, and for a channel that is locally non-stationary in time, not stationary in frequency and with a non-separable dispersion function. To solve this, the orthogonalization technique of the channel is used in conjunction with a windowing scheme in order to generate arbitrarily long realizations of doubly dispersive channels.

A method for generating a tone signal (TS) having a tone frequency, f, wherein the method comprises the following steps: supplying (S1) a binary bit stream (BBS) having a mark pattern with a supply bit rate, BR, to a signal filter unit; and filtering (S2) the supplied binary bit stream (BBS) by said signal filter unit to generate the tone signal (TS), wherein the mark pattern of the binary bit stream (BBS) supplied to said signal filter unit is adapted to minimize a ratio of the supply bit rate, BR, to the tone frequency, f, of the generated tone signal (TS).

An optical transmitter has an optical modulator with a Mach-Zehnder interferometer, a pilot signal generator configured to generate a pilot signal to be superimposed on a drive signal for driving the optical modulator or on a substrate bias voltage applied to the optical modulator, and a controller configured to detect a ratio between a pilot component and a direct current component contained in a light output from the optical modulator and control at least one of an amplitude of the drive signal and a level of the substrate bias voltage such that the ratio becomes a constant value.

A relay transmission system includes a relay unit configured to relay uplink signals and downlink signals in the first and second communication systems, a time division duplex (TDD) information estimation unit configured to estimate a transmission period of network devices in the first communication system on the basis of the uplink or downlink signal of the first communication system that is relayed by the relay unit, a surplus bandwidth determination unit configured to determine a surplus bandwidth in which an uplink signal of the first communication system is not allocated to a relay target of the relay unit during the transmission period on the basis of the number of network devices and a maximum transmission capacity of the network devices, and a bandwidth allocation unit configured to allocate the uplink signal of the second communication system to the relay target of the relay unit in the surplus bandwidth.