Patents of the Mobile Radio Transmission Group

The method involves causing or coordinating transmission of modified signal structures with pilot symbols of base stations with adjusted high power by the base stations of a backbone network. Transmission power of signals and/or signal components is adjusted in the base stations in such a manner that the signals and/or signal components comprise different base stations at a mobile communication terminal of similar level, where the signals are modified by pilot symbols.

The method involves using an extended Kalman-Filter for tracking of a condition, with which an estimation of a condition takes place in a prediction step and estimation of covariance matrix for an action period on basis of a corrected condition. A Kalman amplification, a corrected condition and corrected covariance matrix are computed in a correction step.

A non-loss diversity technique is combined with a local expansion technique shown as a block expansion technique in a code division multiplexing transmission (CDMT) method. Intermittent shift in signals to be transmitted is adapted to an applied spread/code length in a related CDMT system in every dimension, i.e. frequency and/or time.

Keywords: synchronisation, position information

The method involves transmitting redundant signals as macro diversity event from a transmitter of base stations (BS0, BS1) of two or multiple segments by each transmit antenna per base station. A mobile user terminal device (MT0) residing in radio reception region of the stations is received and combined. The redundant signals transmitted in data block form by the stations stay in relationship to each other based on space-time-block coding e.g. Alamouti coding. Usable information is derived from a discriminatable bit error rate performance relative to a radial position for functionalities.

The method involves using a gray-mapping algorithm or a reference algorithm when sending a data packet block for coding and generating data symbols, where the algorithms allow maximum high priori information. A decision is made by receiving a transmitting and receiving station on the basis of the priori information and respective signal to noise ratio to initiate an iterative decoding and reference algorithm. The priori information is present in a receiver of the transmitting and receiving station after transmitting and receiving the data symbols.

A multiple antenna (5) digital data transmission procedure uses time dispersive discontinuous time signal shifts to produce a spectrally discontinuous transmission to provide additional diversity (14, 19) to allow correct detection. Suitable for use with Automatic Repeat reQuest (ARQ) procedures such as incremental redundancy or chase combining to provide additional diversity for transmission error correction and multi-carrier code division multiplexing using time and frequency diversity to improve transmission quality without rate loss.

The device has a connection device (10) that is provided between a presenter-computer (2) and a projector (3). The connection device has an analog or digital video signal from the presenter-uter as an input signal (20), and exhibits two output signals (30). The input signal is applied to a software-processing device, which detects a current presentation image in comparison with the preceding presentation image. Presentation information that is accepted into the processing device is distributed to public over a wireless-LAN (WLAN)-access point-unit of the connection device.

An apparatus for iteratively estimating a channel transfer function of a communication channel from a received signal being a receivable version of a transmit signal, the transmit signal being transmitted through the communication channel, the transmit signal being a frequency-time transformed version of a transmit sequence, the transmit sequence resulting from processing a data sequence using a processing scheme comprises a detector (101) for obtaining an estimate of the data sequence from a version of a spectrum of the received signal, a processor (107) for processing the estimate of the data sequence to obtain an estimate of the transmit sequence using the processing scheme, a channel estimator (113) for estimating the channel transfer function using the estimate of the transmit sequence and the spectrum of the received signal to obtain an estimate of the channel transfer function, wherein the channel estimator is configured for providing a predetermined value as an estimate of the channel transfer function at a frequency point when an amplitude of a value of the estimate of the transmit sequence at the frequency point is below a thresh-old or for combining the value of the estimate of the transmit sequence at the frequency point with a value of the spectrum of the received signal at the frequency point to obtain an estimate of the channel transfer function at the frequency point when the amplitude of the value of the estimate of the transmit sequence at the frequency point is above the threshold, wherein the processor (107) is configured for providing the estimate for the transmit sequence as the version of the spectrum of the received signal for further iteration.

Keywords: Iterative channel estimation

Apparatus and method for detecting a group of received symbolsAbstractAn apparatus for detecting a group of received symbols includes means (18) for providing information on the transmission channel, means (12) for deriving candidate values based on a difference between the group of received symbols and a value dependent on a possible group of transmitted symbols, the code vectors used for CDMA spreading in a transmitter, information on a phase rotation applied to the code vectors during transmission and the information on the transmission channel. The means (12) for deriving the candidate values (14) for each of the possible groups of transmitted symbols is connected to a means (16) for determining received symbols corresponding to a group of transmitted symbols based on the candidate values for the plurality of different possible groups of transmitted symbols.; The multi-user detector based on maximum likelihood sequence estimation or maximum likelihood symbol by symbol estimation with hard or soft decision enhances the perform-ance for multi-channel-CDMA systems by at least 2 dB compared to a detector operating on non-rotated code vectors.

The multiple access communication system, especially OFDMA-CDM system, transmitting digital data symbols in packet form uses automatic repeat request (ARQ) means combined with soft parallel or serial interference cancellation (IC) means to achieve error free multi-user wireless transmission of packets. Superimposed packet allocation for packet transmission is provided where each transmitted packet is associated with one spreading code. An iterative algorithm is applied which is a combination of IC and hybrid ARQ based on soft value combining (SVC), said algorithm exploiting reliability information of erroneously received copies of the same data packet to improve the performance of interference cancellation. Ideal reconstruction of the interference of correctly received packets is performed and reconstructed interference is subtracted from received signal vector. The invention may be used for multi-carrier wireless or wired transmission systems with any type of interference.

Keywords: ARQ, interference cancellation

Antenna lobes are directed to the receiver (2). These emanate from one or more intelligent antenna arrays (5) at the transmitter (1). An adaptive antenna processor (4) controls this process. In determining optimum directions of radiation, the processor exploits actual conditions obtaining in the topographic channels. The form of signals radiated in various directions is changed, such that the spectrum of received signals can be used in reconstitution and detection of the transmitted signal.

Antenna lobes are directed to the receiver (2). These emanate from one or more intelligent antenna arrays (5) at the transmitter (1). An adaptive antenna processor (4) controls this process. In determining optimum directions of radiation, the processor exploits actual conditions obtaining in the topographic channels. The form of signals radiated in various directions is changed, such that the spectrum of received signals can be used in reconstitution and detection of the transmitted signal.