Nokia Corporation

Other

Nokia Mobile Phones Limited

Clive K Tang

Victor Stolpman

Giridhar Dhati Mandyam

Roy Thomas Derryberry

Mohamed A El-Rayes

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.

Adaptive basis functions in a multicarrier communication system

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.

Apparatus, and associated method, for selecting a switching threshold for a transmitter utilizing adaptive modulation techniques

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.

Gradient based method and apparatus for OFDM sub-carrier power optimization

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.

Apparatus, and associated method, for selecting radio communication system parameters utilizing learning controllers

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.

Method and apparatus providing enhanced reservation access mode for a CDMA reverse channel

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.

Multiple user adaptive modulation scheme for MC-CDMA

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. The OFDM transmitter is responsive to the MCS switching thresholds for selecting an appropriate one or ones of said modulators for modulating the data for various ones of the sub-channels.

Method and apparatus providing decentralized, goal-orientated adaptive learning in an adaptive orthogonal frequency division multiplex communication system

Growing community of inventors

Irving, TX, United States of America

Clive K Tang