Abstract: A technique for performing adaptive predistortion in a transmitter includes receiving, at a first input of an error signal unit, a delayed version of a baseband input signal. The technique also includes receiving, at a second input of the error signal unit, a power amplifier feedback signal from an output of a power amplifier. An input error signal that corresponds to a difference between the delayed version of the baseband input signal and the power amplifier feedback signal is then provided at an output of the error signal unit. The input error signal is then received at an input of a signal conditioner. An adjusted error signal that has a lower direct current offset than the input error signal is provided at an output of the signal conditioner.

Abstract: Apparatus, systems, and methods are provided for controlling the output of a transmitter using a digital error signal. A method comprises generating a digital reference signal based on a baseband input signal and converting the digital reference signal to an analog reference signal. The method further comprises generating an analog error signal in response to a difference between the analog reference signal and an analog output signal. The method further comprises generating a digital error signal from the analog error signal, and generating an input signal for the transmitter based on the baseband input signal and the digital error signal.

Abstract: Techniques and technologies are provided for compressing differential samples of bandwidth-limited data and coding the compressed differential samples to reduce bandwidth and power consumption when communicating bandwidth-limited data over a serial interface which couples one integrated circuit to another integrated circuit.

Abstract: Apparatus, systems, and methods are provided for controlling the output of a transmitter using a digital error signal. A method comprises generating a digital reference signal based on a baseband input signal and converting the digital reference signal to an analog reference signal. The method further comprises generating an analog error signal in response to a difference between the analog reference signal and an analog output signal. The method further comprises generating a digital error signal from the analog error signal, and generating an input signal for the transmitter based on the baseband input signal and the digital error signal.

Abstract: A technique for performing adaptive predistortion in a transmitter includes receiving, at a first input of an error signal unit, a delayed version of a baseband input signal. The technique also includes receiving, at a second input of the error signal unit, a power amplifier feedback signal from an output of a power amplifier. An input error signal that corresponds to a difference between the delayed version of the baseband input signal and the power amplifier feedback signal is then provided at an output of the error signal unit. The input error signal is then received at an input of a signal conditioner. An adjusted error signal that has a lower direct current offset than the input error signal is provided at an output of the signal conditioner.

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: Techniques and technologies are provided for compressing differential samples of bandwidth-limited data and coding the compressed differential samples to reduce bandwidth and power consumption when communicating bandwidth-limited data over a serial interface which couples one integrated circuit to another integrated circuit.

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: A method is described for transmitting data from a mobile station to a wireless network, as is a wireless communications system that operates in accordance with the method. The method includes (a) requesting permission to transmit data using an access channel; (b) in response to receiving a permission message from the wireless network, transmitting the data from the mobile station to the wireless network over a control channel using a modulation and channel coding scheme determined in the wireless network, and communicated to mobile station in the permission message; and (c) in response to receiving the transmitted data at the wireless network, soft combining the received data with previously received data, if any, until a desired decoding result is achieved, and transmitting an acknowledgment of data reception to the mobile station. The steps of transmitting and receiving preferably use a code division, multiple access technique.

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: A method is described for transmitting data from a mobile station to a wireless network, as is a wireless communications system that operates in accordance with the method. The method includes (a) requesting permission to transmit data using an access channel; (b) in response to receiving a permission message from the wireless network, transmitting the data from the mobile station to the wireless network over a control channel using a modulation and channel coding scheme determined in the wireless network, and communicated to mobile station in the permission message; and (c) in response to receiving the transmitted data at the wireless network, soft combining the received data with previously received data, if any, until a desired decoding result is achieved, and transmitting an acknowledgment of data reception to the mobile station. The steps of transmitting and receiving preferably use a code division, multiple access technique.