863 results about "Channel power" patented technology

A WCDMA system includes a Base Station (BS) transmitter, or forward transmitter and a pilot channel that transmits control signals between the BS and a Mobile Station (MS) to reconfigure their transmitter/receiver. Reconfiguration is performed according to the prediction of the channel attenuation and the threshold set at the BS or MS based on its channel power probability density function separated into three distinct equal probable regions. In one embodiment, Seamless Rate Change (SRC)/Transmitter Power Control (TPC) logic uses the predicted channel attenuation to signal both the transmitter and the receiver in a channel to reconfigure their transmit power level according to the power density function (pdf) of the channel power and threshold level. A transmission rate is reduced when the power level is below the threshold and increased when the channel power is above threshold. The pilot channel is used to signal the mobile station and the base station.

A WCDMA system includes a Base Station (BS) or forward transmitter and a pilot channel that transmits control signals between a Mobile Station (MS) and BS to reconfigure their transmitter/receiver according to the prediction of the channel power and channel power probability density function separated into three distinct equal probable regions. Data signals are encoded using a one-half Viterbi encoder and interleaved. The interleaved data bits are modulated using Quadrature Phase Shift Keying (QPSK) modulation. The QPSK data is multiplexed with the pilot channel and spread by an appropriate code in an OFDM transmitter modified by a long code. Output of the transmitter may be provided to two diverse antennas for reliable communications to the receiver. Data may be received at two diverse antennas. The outputs are provided to match filters coupled to a coherent rake receiver and a channel prediction system. The future attenuation of the channel coefficients and power are determined by the prediction system for several milliseconds. The power levels of each finger in the Rake receiver can be predicted and the strongest ones used in determining the optimum transmitter power or rate control for operating the system transmitters and receivers based on computing a long range power prediction of each finger of a rake receiver.

A shared signaling channel can be used in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system to provide signaling, acknowledgement, and power control messages to access terminals within the system. The shared signaling channel can be assigned to a predetermined number of sub-carriers within any frame. The assignment of a predetermined number of sub-carriers to the shared signaling channel establishes a fixed bandwidth overhead for the channel. The actual sub-carriers assigned to the channel can be varied periodically, and can vary according to a predetermined frequency hopping schedule. The amount of signal power allocated to the signaling channel can vary on a per symbol basis depending on the power requirements of the communication link. The shared signaling channel can direct each message carried on the channel to one or more access terminals. Unicast messages allow the channel power to be controlled per the needs of individual communication links.

A method of transmitting data using a generalized phase shift based proceding or an extended phase shift precoding scheme in a multiple-antenna system using a plurality of subcarrier and a transceiver for supporting the same are disclosed. A phase shift based precoding matrix may be generalized and determined by a product of a diagonal matrix for phase shift and a unitary matrix for maintaining orthogonality in spatial domain. The diagonal matrix may be extended by a product of a proceding matrix for increasing channel power and the diagonal matrix for phase shift. The design of the transceiver can be simplified or communication efficiency can be improved by generalizing and extending the phase shift based proceding.

A distributed dynamic channel allocation algorithm for a multi-carrier CDMA cellular system having at least one mobile base station. The distributed dynamic channel allocation algorithm uses channel power measurements from both the requesting mobile station and the mobile base station attempting to allocate an available resource to the mobile station. The distributed dynamic channel allocation algorithm attempts to allocate the best available resource for the requesting mobile station, in terms of interference, while minimizing the amount of interruption that the allocated resource may cause to existing connections in neighboring cells. Thus, the distributed dynamic channel allocation algorithm follows a “least-interference, least-interruption” strategy. The distributed dynamic channel allocation algorithm is load balancing, since it tends to assign new resources to mobile base station with lighter loads.

Channel estimation techniques are provided for a receiver of a wireless communication system using orthogonal frequency division multiplexing (OFDM), including legacy 802.11a and various extended rate systems. Training signals are received from one or more receive antennas. An estimated channel impulse response is computed from the received training signals by reference to a training sequence. The estimated channel impulse response is truncated in the time domain based on channel power and noise data. Channel response tracking techniques may also be implemented to correct for variations in channel response over the transmission time of a packet.

Disclosed is a channel power adjustment method and system based on positional information of plural self-organizing subnets in a restricted area. The method includes a first setting step of setting, based on the positional information of the plural self-organizing subnets, a positional priority for each of the plural self-organizing subnets; and a first adjustment step of adjusting, at least partially based on the positional priorities of the plural self-organizing subnets, a power of a first device in a first self-organizing subnet working in a first channel, satisfying a predetermined rule to a first power of the first channel.

The invention discloses an application of selecting round key XOR input to perform side-channel power analysis of an SM4 cryptographic algorithm. The application is characterized in that in the process of the side-channel power analysis of the SM4 cryptographic algorithm, S boxes or round functions are selected to serve as attack points to establish a Hamming distance (HD) model, the round key XOR input is taken as a preceding state v1 of the HD model, and when the S boxes are attacked, the subsequent state v2 of the HD (v1, v2) model is S box output; and when the round functions are attacked, the subsequent state v2 of the HD (v1, v2) model is output/input of the round functions. The method can be applied to the side-channel power analysis of a CPA (correlation power analysis) and DPA (differential power analysis) of the SM4 cryptographic algorithm. With the adoption of the method, the correlation between a right guessing secret key and a power message is improved, the effectiveness of the analysis is enhanced, and the success rate is increased.

A 3D printer device utilizing at least one Quantum Cascade Laser (QCL) image head having at least one beam focused in a focal plane of the device for building on a surface of the device a 3D model of a target object from a digital image. The inventive 3D printer is more compact in size due to the use of QCL image heads, which provides focused wavelengths of QCLs matching the absorption properties in plastics for more efficient absorption of the radiant energy. Each QCL channel power in the inventive 3D printer can be doubled by combining two lasers with a polarization beam splitter. The QCL image head is provided with Pulse Width Modulation (PWM) for compensating for imaging speed. The invention includes a method for scaling up the building speed of 3D printing regardless of detail level. The invention discloses an affordable 3D printer using QCL technology while maintaining high standards of resolution, use of quality materials, and rapid building speeds.

The invention discloses a plaintext or ciphertext selection based side channel power analysis attack method on round function output of the SM4 cipher algorithm. The method includes the steps of S1, selecting plaintext or ciphertext to input X<i+0>, X<i+1>, X<i+2> and X<i+3> on the condition of allowing the exclusive OR result of the X<i+1>, X<i+2> and X<i+3> to be a constant value and guaranteeing randomness of the X<i+0>, utilizing side channel power attack processes to attack the output C of linear transform L of each round of the first four round functions, and deducing inversely to acquire the round key rk of the first four round functions in encryption or decryption according to the output C; S2, according to the round keys rk<0>, rk<1>, rk<2> and rk<3> of the first four found functions, inversely calculating the initial key by a key expansion algorithm. The method can realize power analysis attack by means of multiple attacks and can attack with selection of proper-length bits according to actual computing capacity, thus flexibility, effectiveness and success rate of analysis are improved.