62 results about "Rake combining" patented technology

A receiver includes a receiver circuit that decodes multiple signals of interest contained in a composite received signal. The receiver comprises a plurality of successive signal detection stages to detect respective signals contained in the composite received signal. Each detection circuit comprises at least one Generalized RAKE combining circuit and generates a detected signal at an output. Each but the last stage further comprises a signal regeneration circuit that cancels the signal of interest detected by that stage from a stage input signal provided to the next stage such that successive detection of the signals of interest benefits from cumulative cancellation of the previously detected signals.

A receiver includes a receiver circuit that decodes multiple signals of interest contained in a composite receive signal. The receiver comprises at least one Generalized RAKE combining circuit and a joint demodulation circuit and generates a detected signal at an output. The joint demodulation circuit contains a reduced search soft value generator circuit and generates soft bit values that represent coded bits received from the transmitter.

One aspect of the present invention is a method for combining a direct sequence spread spectrum signal comprising signal components that each may be characterized by a space variable and a time variable comprising the steps of: dispreading the signal components; and determining a set of combining coefficients from the signal components using a Minimum Mean Square Error combining method that considers the space and time variables of the signal components in parallel. The Minimum Mean Square Error combining methods may utilize iterative methods such as the Least Mean Squares method or the Recursive Least Squares method.

In a mobile communication system, the tracking of synchronization is conducted in a stable state even in a multipath environment. A delay profile detector calculates a delay profile a(n) using a despread signal for each processing unit n. A delay profile averaging unit averages a(n) to produce Ave(|a(n)|<2>). A data symbol detector conducts rake combining of the despread signal using a(n) and Ave(|a(n)|<2>). According to a(n) and Ave(|a(n)|<2>, a weighting function unit calculates a representative value representing delay waves. A loop filter generates a control signal in response to the representative value. A clock controller controls a spread code generator according to the control signal.

Multipath components of a signal transmitted through a time-varying digital radio channel are received with individual delays (τ) within a range of possible delay values. An instantaneous delay profile indicating an instantaneous magnitude (g(τ)) for each of a number of individual delays (τ) is calculated repetitively, and an averaged delay profile indicating an averaged magnitude for the individual delays is generated from a number of repetitively calculated instantaneous delay profiles. The averaged delay profile is limited to comprise only delay values in a subset (W₁, W₂, W₃) of the range of possible delay values. The delay of each individual multipath component is estimated from the averaged delay profile; and at least some estimated delays are used for RAKE combining. In this way, the benefits of an averaged delay profile are achieved without the need for the additional storage and computational resources normally required by a general averaged delay profile image.

An SIR calculation section 130 calculates an SIR value D4 after RAKE combining from a desired signal power value for each finger calculated by an RSCP calculation section 110 and an interference signal power value for each finger calculated by an ISCP calculation section 120. An SIR correction section 140 corrects the SIR value D4 using the number of discrete signals used to calculate RSCP, the number of discrete signals used to calculate ISCP and the number of fingers L used for RAKE combining. As a result, even when the number of discrete signals used to calculate RSCP is different from the number of discrete signals used to calculate ISCP, it is possible to realize an SIR measuring apparatus 100 capable of resolving a static error with respect to a theoretical value and realizing measurements at a high degree of accuracy and freedom.

A receiver of a spread spectrum communication system comprises a plurality of despreading circuits, a rake circuit, and a path searcher. The plurality of despreading circuits despreads received signals having multipath components at predetermined timing allocated thereto. The rake circuit performs rake combining of the signals despread by despreading circuits. The path searcher forms a first window showing a part of a search range and calculates delay profile data of said received signals in said first window to search an effective path, forms at least one second window in the search range except said first window and calculates delay profile data of said received signals in said second window, and detects timing at which said received signals are despread based on calculated delay profile data to allocate the detected timing to said despreading circuits.

In an adaptive array antenna receiving apparatus which is used in a CDMA communication system and which includes a predetermined number L (L is an integer greater than 1) of fingers, no correlation exists between respective fingers. An adaptive update algorithm of calculating an antenna weighting factor by the use of an N-order correlation matrix independently for the respective fingers is equivalent to an adaptive update algorithm of calculating an (N×L)-order correlation matrix. In the adaptive array antenna receiving apparatus, the antenna weighting factor is controlled by the use of the adaptive update algorithm independently for the respective fingers so that a mean square of a common error signal produced by a subtractor (8) after rake combination by a rake combining circuit (6) is minimized. In this manner, the amount of calculation in the adaptive update algorithm used in all MMSE control circuits is considerably reduced proportionally from (NL)² to N²L. As a consequence, the processing load upon the DSP can be decreased.

MIXR is implemented with a realistic amount of hardware even when the number of detected paths is large. From among path timings detected by a path searcher and MICTs generated based on the detected path timings, as many timings as there are fingers are selected by a timing selector and the selected timings are assigned to the fingers. When selecting the timings, the value of SNIR expected to be achieved by RAKE combining in a RAKE combiner, for example, is predicted by calculation from a received signal, and the path timing and MICT that maximize the SNIR are selected.

In maximum delay time setting section 106, a delay time width W′ used for cancelling the interference is set using the delay profile. In the present embodiment, delay spread is calculated and a delay wave included in the delay spread is set as W′. First, the delay spread is calculated in delay spread calculating section 1061 of maximum delay time setting section 106. That is to say, the standard deviation of the delay profile is calculated. The calculated delay spread is outputted to maximum delay time determining section 1062. The maximum delay time (window width) W′ is determined in maximum delay time determining section 1062 based on the delay spread. Therefore, the delay wave included in the maximum delay time which is determined by such a way is set to be an object of interference cancellation in joint detection. Thus, besides interference cancellation performance, optimization of calculation scale can be planned without losing performance of RAKE combining.

In a wireless diversity reception apparatus, a combining unit RAKE-combines signals of multipaths transmitted from a mobile station and received by a plurality of antennas. An antenna failure detection unit detects an antenna failure based on selection result information representing paths used for RAKE combining. A mobile station control unit calculates the total reception power value of a cell in accordance with an antenna failure detection state and outputs power control information to make the total reception power value of the cell match a target total reception power value. A transmission unit transmits the power control information to the mobile station to perform transmission power control of the mobile station. A wireless diversity reception method is also disclosed.

The present invention provides a CDMA receiving apparatus capable of corresponding to the service types of data and system conditions flexibly and efficiently, so as to achieve such processing for electric power control, diversity control and the like, requested to have real-time property. A CDMA signal inputted into a memory is searched by searcher units of each reception processing block. Voice data and low-speed data are demodulated immediately by a finger unit for data field and a finger unit for control field, and combined by RAKE-combining units. Data fields of packet data and high-speed data are accumulated in memories for data field and demodulated by finger units for data field successively based on path information stored in memories for path information.