Telefonaktiebolaget Lm Ericsson (publ)

Hitachi, Ltd.

Fipa Frohwitter Intellectual Property Ag

Hitachi Communication Technologies, Ltd.

Riaz Esmailzadeh

Takashi Yano

Nobukazu Doi

Karim Jamal

Erik Bengt Dahlman

Yi-Pin Eric Wang

Jonas B Karlsson

Paul Peter Butovitsch

Maria Gustafsson

Sandeep Chennakeshu

Per Hans Willars

Masayuki Ariyoshi

Christiaan Roobol

Johan Nystr&ouml;m

Per Johan Anders Nystr&ouml;m

Erik B L Dahlman

Bo Lyckeg&aring;rd

In order to accomplish efficient communication of data between a base station and a plurality of mobile terminals, particular orthogonal codes are transmitted from the mobile stations to the base station as alert signals indicating the presence of data to be transmitted. The base station checks whether particular orthogonal codes are contained in the alert signals, and when the particular orthogonal codes are detected in the alert signals, information representing the detected orthogonal codes and the schedules for transmitting the data from the mobile terminals to the base station are transmitted from the base station to the mobile terminals as an alert response to the alert signals. When the information representing the orthogonal codes used for the alert signals are contained in the alert response transmitted from the base station to the mobile terminals, the data waiting to be transmitted is transmitted from the mobile terminals to the base station according the data transmission schedules in the alert response.

Method of mobile communication and apparatus therefor

A wireless telecommunications system capable of transmitting desired information to a plurality of mobile stations efficiently is adapted to transmit the information to the plurality of mobile stations by forming a signal beam that covers these mobile stations simultaneously. Since information can thus be sent to a plurality of mobile stations at the same time, it is possible to send information in a highly efficient. In addition, because transmission power can be reduced, interference acting upon other mobile stations can be suppressed.

Telecommunications system, base station thereof and telecommunications method

A method and apparatus for controlling the power of a signal transmitted between a base station and a mobile terminal which constitute a mobile communication system. At least one of the base station and the mobile terminal has functions to compare a predetermined reference value and a necessary transmission power obtained as a result of transmission power control in order to compensate for a signal intensity fluctuation occurring on a link between the base station and the mobile terminal, temporarily stopping the transmission if the necessary transmission power is larger than a predetermined permissible value, and transmit the signal if the necessary transmission power is equal to or smaller than the predetermined permissible value.

Transmission power control method and apparatus for mobile communication system

Transmission control method and apparatus for mobile communication system

Method and apparatus for minimizing the processing delay incurred by an IC receiver over conventional receivers in a CDMA cellular system are disclosed. The method and apparatus involve operating the conventional receiver and the IC receiver in parallel to each other. Data from the conventional receiver are then used to supplement data from the IC receiver in order to minimize the delays incurred by the IC receiver.

Zero delay interference cancellation

The purpose of the present invention is to offer a structure of a CDMA system having a power control method and interference cancellers which can effectively increase the system capacity and is resistant to sudden changes on the communication path, and to achieve a power control method with a fast response capable of preventing unnecessary increases in the transmission power (and multiple access interference) of the uplink by reflecting the values of the post-interference cancellation signal-to-interference power ratio in the generation of power control command information. The invention is directed to a power control method in a communication system for performing communications by code-division multiple access between a mobile station and base station, wherein a multiple access interference signal contained in a reception signal from the mobile station is cancelled, a post-interference cancellation signal-to-interference power ratio of the reception signal currently received is estimated, a power control command is generated by comparing the estimated post-interference cancellation signal-to-interference power ratio and a target value for power control, and transmitting this power control command to the mobile station to control the transmission power of the mobile station.

Communication method and its power control method

A special coding scheme is disclosed for more effectively acquiring a long code and frame timing during a cell search in a CDMA communications system. A code set of length M Q-ary code words including symbols from a set of Q short codes is defined with certain properties. The primary property to be satisfied is that no cyclic shift of a code word yields a valid code word. The other properties to be satisfied are that there is a one-to-one mapping between a long code message and a valid code word, and a decoder should be able to find both the random shift (thereby implicitly finding the frame timing) and the transmitted code word (i.e., its associated long code indication message) in the presence of interference and noise, with some degree of accuracy and reasonable complexity.

Cell searching in a CDMA communications system

The invention is concerned with a radio receiver station, a multi-user interference cancellation unit and a multi-user cancellation method in a system with several transmitting radio stations. In the method, a radio signal is received as a sum of the signals from at least two of the transmitting radio stations in the system. Interference from at least two of the transmitting radio stations is cancelled. The interfering signals from at least some of the transmitting radio stations are processed in at least two separate operations in one or more stages, the result of each separate operation being taken into consideration in the estimation of the desired modulated signal sent to the receiver. Preferably, a part of the interfering signals is processed in one of the separate operations, while the rest of the interfering signals are processed in the other separate operations. If the cancellation is carried out in more than one step, the cancellation results of the first cancellation stage are used in the second interference cancellation stage, the method being correspondingly continued in the possible further cancellation stages.

Interference cancellation in radio stations

In a communications system, communications resources are allocated in a dynamic, &ldquo;as needed&rdquo; fashion. No explicit signaling is needed to exchange information pertaining specifically to an allocated communications resource. Instead, resources are implicitly allocated by using one or more parameters known to both the radio access network and mobile station that are more or less unique to the mobile station. Such parameters are used to generate or address a communications resource for use by the mobile station. The parameters might, for example, be information readily acquired or communicated as a result of a synchronization procedure, a mobile station registration procedure, a mobile station access procedure, a paging procedure, etc. Example parameters may include a system frame number, a system identification, a radio access network identification, a base station identification, a cell identification, a mobile station-associated signature, an access reference number corresponding to the mobile station, a time instant when an acknowledgment message is received, etc.

Implicit resource allocation in a communication system

A method is disclosed for processing mobile-originated random access requests in a mobile telecommunications system that randomly selects new signatures for re-transmissions in the event that collisions have occurred. As such, the random access re-transmissions are randomized over the signature domain instead of just over the time domain. Consequently, the disclosed invention significantly shortens random access delays caused by collisions or erroneous arrivals at base station receivers, and also significantly reduces the interval between random access re-transmissions.

Random access in a mobile telecommunications system

A method for improving the performance of a random access communications system in a variable radio environment is disclosed, whereby at least one valid set of burst signatures is used for transmission by one or more mobile stations. Each set includes at least one signature with a different signature-length than the signatures in other sets. The different signature-lengths can be optimized for the operational environments involved (e.g., longer signatures for slower-moving mobile stations, and shorter signatures for high-speed mobile stations). Alternatively, at least one differentially-encoded signature is used for random access transmissions, in order to reduce the radio channel's sensitivity to large doppler spreads and frequency errors.

Growing community of inventors

Yokohama, Japan

Riaz Esmailzadeh