Abstract: In accordance with some embodiments of the present disclosure, a method may include digitally pre-distorting a digital baseband signal with an opposite phase of a C-IM3 distortion term such that the pre-distortion and C-IM3 distortion cancel each other out in a transmitter. The method may also include digitally conditioning the pre-distorted digital signal in order to provide a flat amplitude response of a composite filter comprising a baseband filter and a digital half-band filter of the transmitter, and to provide a linear phase response for the composite filter.

Abstract: In accordance with some embodiments of the present disclosure, a method may include digitally pre-distorting a digital baseband signal with an opposite phase of a C-IM3 distortion term such that the pre-distortion and C-IM3 distortion cancel each other out in a transmitter. The method may also include digitally conditioning the pre-distorted digital signal in order to provide a flat amplitude response of a composite filter comprising a baseband filter and a digital half-band filter of the transmitter, and to provide a linear phase response for the composite filter.

Abstract: Embodiments of wireless devices and transmitters are provided, which perform embodiments of automatic gain control methods. The embodiments of wireless devices and transmitters include a ramp generator, a digital gain signal generator, a combiner, and a variable gain amplifier. The ramp generator is adapted to receive a gain control input signal and to generate a gain ramp signal based on the gain control input signal. The digital gain signal generator is adapted to generate and incorporate a gain arc into a digital gain signal. A combiner is adapted to receive and combine a digital input signal with the digital gain signal, to generate a pre-compensated digital signal. The variable gain amplifier is adapted to apply gains indicated in the gain ramp signal to a pre-adjusted analog signal, which is generated based on the pre-compensated digital signal, in order to generate a gain-adjusted analog signal.

Abstract: Embodiments of wireless devices and transmitters are provided, which perform embodiments of automatic gain control methods. The embodiments of wireless devices and transmitters include a ramp generator, a digital gain signal generator, a combiner, and a variable gain amplifier. The ramp generator is adapted to receive a gain control input signal and to generate a gain ramp signal based on the gain control input signal. The digital gain signal generator is adapted to generate and incorporate a gain arc into a digital gain signal. A combiner is adapted to receive and combine a digital input signal with the digital gain signal, to generate a pre-compensated digital signal. The variable gain amplifier is adapted to apply gains indicated in the gain ramp signal to a pre-adjusted analog signal, which is generated based on the pre-compensated digital signal, in order to generate a gain-adjusted analog signal.

Abstract: Apparatus, and an associated method selects an adaptive switching threshold level responsive to a constrained optimization scheme. The switching level is selected by an LRI function forming a portion of a transmitting station, such as a base transceiver station operable in a cellular communication system. The switching threshold level is utilized in the selection by an adaptive modulator of a modulation parameter by which data transmitted by the transmitting station is encoded or modulated.

Abstract: A method for transmitting a signal uses a channel impulse response to determine a sub-carrier frequency function for at least two different basis functions. For each of the at least two sub-carrier frequency functions, a performance measure is predicted using the associated frequency function. These predicted performance measures are then stored and compared. One of the at least two basis functions are selected based on the comparing. A signal to be transmitted is converted from the frequency to the time domain using the selected basis function, and then transmitted over multiple sub-carriers via a time radio-frequency channel. Adaptive modulation, coding, bit and/or power loading may also be used in conjunction with the adaptive basis functions. A transmitter, modulator, and computer program are also described.

Abstract: Apparatus, and an associated method, for selecting operational parameters pursuant to which a radio communication system is operable. The operational parameters form, for instance, adaptive switching thresholds used in an adaptive modulation scheme. Separate learning controllers are configured to operate independently and cooperatively to select the adaptive switching thresholds, or other operational parameters. Iterative operation of the learning controllers causes the values to converge to optimal values.

Abstract: In one aspect thereof this invention provides a method to increase data throughput in an Orthogonal Frequency Division Multiplex (OFDM) wireless communications system. The method includes modeling data throughput as a function of received Signal to Noise Ratio (SNR) with a sigmoid function to produce a throughput curve characterized as having a lower knee region and an upper knee region; and performing a gradient ascent search along the throughput curve by varying the power of a plurality of sub-carriers so as to remove power from any sub-carrier having a received SNR to the left of the lower knee region, and to re-allocate the removed power to sub-carriers having a received SNR to the right of the lower knee region.

Abstract: In recent years adaptive modulation has emerged as a popular technique to improve data throughput and system capacity in a wireless system. The basic idea is to adapt the modulation scheme to the fading channel quality, using different schemes for different channel conditions. Therefore one primary issue is to determine the switching thresholds between the modulation schemes. Typically these thresholds are fixed according to a certain criterion. This paper introduces a novel adaptive learning approach that is capable of dynamically adjusting the thresholds so as to maximize the throughput. A key feature of the proposed self-learning scheme is that no dedicated training signal is required, instead it utilizes the long-term average throughput to continuously update the thresholds as the data is transmitted.

Abstract: In a multi-user frequency domain spreading downlink MC-CDMA system. a group of sub-carriers can be replaced by an equivalent sub-carrier of a conventional OFDM modem for purposes of resource allocation to improve the system performance. The chips for a given user are spread only within the group. Confinement insures synchronization between different users' chips that is essential to the recovering and separation of user symbols at the receiver. There is no limit imposed on the group size, which permits different spreading code lengths to be used for different scenarios or for performance tuning.

Abstract: Disclosed is an OFDM communications system and a method of operating the OFDM communications system. The system includes an OFDM transmitter for transmitting data over a plurality of OFDM sub-channels, where the OFDM transmitter has a plurality of modulators of different types. The system further includes an OFDM receiver for receiving the data from the plurality of OFDM sub-channels, where the OFDM receiver has a plurality of corresponding demodulators of the different types. The system further includes, in accordance with this invention, an adaptive learning automata that contains a group or team of independent, decentralized automaton operating in accordance with a game theory-based approach. Each of the plurality of automaton are responsible for managing one MCS switching threshold value so as to maximize at least one selected performance criterion.

Abstract: Disclosed is a method to operate an orthogonal frequency duplex multiplexing (OFDM) communications system, and an OFDM system that operates in accordance with the method. The method includes, when transmitting data over a plurality of OFDM sub-channels from an OFDM transmitter (12A) to an OFDM receiver (12B) through a channel (24), operating an adaptive learning automaton (50) to adjust values of modulation coding scheme (MCS) switching thresholds so as to maximize at least one selected performance criterion; based on the values of the switching thresholds, selecting a MCS and modulating data with the selected MCS and transmitting the modulated data over at least some of the sub-channels. The method further includes receiving the data at the OFDM receiver and demodulating the received data using a demodulator that corresponds to the selected MCS.

Abstract: Apparatus, and an associated method, for selecting operational parameters pursuant to which a radio communication system is operable. The operational parameters form, for instance, adaptive switching thresholds used in an adaptive modulation scheme. Separate learning controllers are configured to operate independently and cooperatively to select the adaptive switching thresholds, or other operational parameters. Iterative operation of the learning controllers causes the values to converge to optimal values.

Abstract: In recent years adaptive modulation has emerged as a popular technique to improve data throughput and system capacity in a wireless system. The basic idea is to adapt the modulation scheme to the fading channel quality, using different schemes for different channel conditions. Therefore one primary issue is to determine the switching thresholds between the modulation schemes. Typically these thresholds are fixed according to a certain criterion. This paper introduces a novel adaptive learning approach that is capable of dynamically adjusting the thresholds so as to maximize the throughput. A key feature of the proposed self-learning scheme is that no dedicated training signal is required, instead it utilizes the long-term average throughput to continuously update the thresholds as the data is transmitted.

Abstract: Apparatus, and an associated method selects an adaptive switching threshold level responsive to a constrained optimization scheme. The switching level is selected by an LRI function forming a portion of a transmitting station, such as a base transceiver station operable in a cellular communication system. The switching threshold level is utilized in the selection by an adaptive modulator of a modulation parameter by which data transmitted by the transmitting station is encoded or modulated.