Abstract: A method for synchronizing measurements in a mobile communication apparatus having a first active radio access means (100) adapted to communicate according to a first radio access technology (RAT) and at least a second passive radio access means (200) adapted to communicate according to a second RAT. A time reference common to the first and the second access means (100) is generated. At least one time schedule is obtained, said schedule indicating at least one time gap wherein the second access means (200) is allowed to be active. The activation time of the schedule is based on the common time reference. An arrangement adapted to generate the common time reference and the time schedule is also disclosed.

Abstract: A method and system enables matched filters of a CDMA system to be simplified using a two stage search. A course stage and a fine stage jointly produce the location(s) of received signal path-rays. In a first stage, an oversampled digital signal is decimated, and the decimated signal is applied to a matched filter to eventually produce an approximate location. In a second stage, the oversampled signal is shifted based on the determined approximate location and then correlated to a generated code, and a more-exact location is selected from the outputs of the correlations. Alternatively, a shifted version of the generated code is correlated to the oversampled signal, and the more-exact location is selected from the outputs of those correlations.

Abstract: Coded digital data symbols sent from a transmitter through a transmission channel of a communications network are received in a receiver. An estimate, represented by a first number of bits, of a sent data symbol is calculated, and a second number of bits, lower than the first number, is selected from the estimate to achieve a rounded estimate represented by the second number of bits. The rounded estimate is decoded to achieve a decoded data symbol. A target value for a block error rate of the transmission channel is received from the network; and the second number of bits is selected in dependence on the target block error rate value. Thus an optimal rounded estimate is provided in most situations, and the method can be performed with the limited computational resources of a terminal.

Abstract: The uplink transmission timing from a mobile communications device is defined with reference to the downlink reception timing of signals from a particular reference cell. When that reference cell is removed from the active set, there is defined a virtual reference cell, the timing of which is defined with reference to one or more of the cells remaining in the active set, such that the timing of this new virtual reference cell corresponds to the timing of the previous reference cell. The timing of the uplink transmission from the user equipment are then defined with reference to the new virtual reference cell, in the conventional way. This has the advantage that, following a soft handover, it is not necessary to adjust the timing of uplink transmissions from the user equipment.

Abstract: A mobile terminal can identify cellular control channels that can be received by the mobile terminal from a cellular system, by identifying a cellular control channel that can be received from a history list of cellular control channels that were previously received by the mobile terminal. A next cellular control channel that can be received by the mobile terminal then is scanned for, by skipping at least one cellular control channel that is adjacent the cellular control channel that was identified, based on channel allocation rules in the cellular system.

Abstract: A channel estimate generator generates a plurality of channel estimates and a Doppler frequency estimator uses two or more channel estimates to generate a Doppler frequency estimate. The Doppler frequency estimator generates the Doppler frequency estimate by calculating the normalized distance between two consecutive channel estimates. A receiver uses the Doppler frequency estimate to either (1) adjust the receiver, (2) estimate the velocity of the receiver, (3) determine whether it is necessary to search for new paths, or (4) predict or track new paths. The receiver can use a moving average of Doppler frequency estimates or a weighted combination of Doppler frequency estimates from different paths of a received signal to calculate the Doppler frequency estimate.

Abstract: A mobile terminal can identify cellular control channels that can be received by the mobile terminal from a cellular system, by identifying a cellular control channel that can be received from a history list of cellular control channels that were previously received by the mobile terminal. A next cellular control channel that can be received by the mobile terminal then is scanned for, by skipping at least one cellular control channel that is adjacent the cellular control channel that was identified, based on channel allocation rules in the cellular system.

Abstract: Method and system are disclosed for providing advanced RAKE delay control in wireless communications systems. The RAKE delay control method and system of the invention is capable of tracking presently known paths over time and merging the tracking results with new path searcher results. The invention is particularly suitable for devices where the resources (e.g., computational load, power) available for detecting the multipath components are limited. The result is a resource efficient architecture for positioning the RAKE fingers to best extract the signal power available in the channel and to utilize the inherent diversity due to the multipath nature of the signal.

Abstract: Channel estimation is performed in a mobile communications system. In order to reduce the computational load, and thereby decrease power consumption, a polynomial expression is used to approximate a Minimum Mean Squared Error (MMSE) based channel estimator with respect to Doppler and SIR variations. A lookup table may be used to supply coefficients for the polynomial expression. In another aspect of the invention, coefficients for the polynomial expression may, themselves, be approximated by a second polynomial expression.

Abstract: A receiver can identify the source of a signal from an unsynchronized source. The receiver has an antenna for receiving two signals. The receiver correlates the first signal with a code to find a first location in time, and correlates the second signal with the same code to find a second location in time. The receiver calculates a time difference between the first location in time and the second location in time and uses the time difference to identify the source of the two signals. A group of base stations or directional antennas use the same long code and synchronization codes. However, each source shifts the long code by a different amount so that for any two sources there is a unique difference between the shifts in the long code. Each source shifts a set of synchronization codes the same amount as the long code. The synchronization codes can be any short code that is relatively easy for the mobile station to detect.

Abstract: A spread spectrum signal is processed by correlating the spread spectrum signal with a spreading sequence at a first plurality of correlation times to produce a first plurality of time-offset correlations. The first plurality of time-offset correlations is processed to produce a first symbol representation for a symbol. A first quality is determined for the first symbol representation. Responsive to the determined first quality, it is determined whether to further process the first symbol representation or to process a second symbol representation for the symbol generated from the spread spectrum signal. The first quality may be determined, for example, by decoding the first symbol representations to generate a decoding metric or error check indicator, such as a CRC result. The symbol representations may be generated and/or evaluated for quality in a serial fashion or a parallel fashion.

Abstract: A method, apparatus, and system perform fast sector identification and base station synchronization. The base station transmits information in primary and secondary control channels to the remote station. The remote station performs synchronization using information in the primary and secondary control channels. A group of identification codes corresponding to the sector is determined using information in the secondary control channel. If this does not result in identification of the sector, an identification code corresponding to the sector is determined from information in the primary control channel. If this does not result in identification of the sector, the sector is identified based on information multiplied with symbols, e.g., pilot symbols, in the primary control channel, without having to decode the BCCH.

Abstract: A mobile communications terminal for use in a cellular communications system e.g. CDMA systems, comprising an electronic circuit (200) for receiving a wire-less communications signal carrying signal channels having processing means for extracting the signal channels. The electronic circuit (200) is adapted to classify a type of interference, affecting the communications quality, by evaluating signals selected in the electronic circuit that are selected as signals having information for classifying a type of interference in one of at least two predetermined classes of interference.

Abstract: The present invention provides a system and method for reducing the power consumed by a RAKE receiver. In exemplary embodiments of the present invention, an environment variation estimator is implemented in a CDMA mobile station. The environment variation estimator is connected to the searcher of the RAKE receiver and provides an estimate of the rate at which the mobile station's environment is changing. By providing an estimate of the rate of change of the mobile station's environment, the duty cycle of the searcher can be optimized, thereby reducing the overall power consumed by the receiver. By also providing the estimate to the RAKE fingers, channel tracking can be improved.

Abstract: A method and apparatus increase a maximum available bit rate on a single data link, in order to gain capacity within single cells. An orthogonal frequency division multiplex signal is filtered by a pulse shaping operation so as to suppress side lobes of the signal. This pulse shaping introduces known inter symbol interference (ISI) and loses orthogonality between subcarriers. However, a receiver utilizes the idea of overcoming ISI by applying equalization to the signal such that the loss of orthogonality is overcome.

Abstract: A method of a mobile radio system for synchronization a transmitter and receiver. The system relates to MC/DS-CDMA-system. In the system information is transmitted digitally in frames. For that purpose a data channel, a pilot channel and a synchronization channel are created. In the data channel the data blocks D0, D1, D2 etc are separated by a guard space .DELTA.. In the pilot channel, respective the synchronization channel, the information is arranged in blocks which are synchronous with each other. The repeating distance, A, of the pilot channel, corresponds to the length of one of the data blocks D0, D1, D2 etc. The repeating distance for the synchronization channel is S, corresponding to a number of blocks in the data channel. In the synchronization channel information is introduced into the blocks which indicates their relation to the data channel.

Abstract: A random access protocol system and method for communicating between a mobile station and a base station in a multi-access digital radio communication system, including the steps of cyclically repeating a random access sequence and transmitting each cyclically repeated random access sequence in an orthogonal frequency division multiplex format from the mobile station as an uplink transmission.