Abstract: A method includes receiving at least two space-time coded signals from an antenna system associated with a first station, determining complex channel state information based on the received space-time coded signals, and sending the complex channel state information to the first station. In an alternative embodiment, a method includes transmitting at least two space-time coded signals in respective beams of a multi-beam antenna array, measuring a channel impulse response for each space-time coded signal at a second station, and sending an indicia of a selected set of least attenuated signals from the second station to the first station. The multi-beam antenna array is associated with a first station. The beams transmit a signature code embedded in each respective space-time coded signal, and the signature codes are orthogonal so that the second station can separate and measure the channel impulse response corresponding to each space-time coded signal.

Abstract: A method includes receiving at least two space-time coded signals from an antenna system associated with a first station, determining complex channel state information based on the received space-time coded signals, and sending the complex channel state information to the first station. In an alternative embodiment, a method includes transmitting at least two space-time coded signals in respective beams of a multi-beam antenna array, measuring a channel impulse response for each space-time coded signal at a second station, and sending an indicia of a selected set of least attenuated signals from the second station to the first station. The multi-beam antenna array is associated with a first station. The beams transmit a signature code embedded in each respective space-time coded signal, and the signature codes are orthogonal so that the second station can separate and measure the channel impulse response corresponding to each space-time coded signal.

Abstract: The invention relates to a method of performing code acquisition on a signal to be received and to a receiver implementing the method. In the method the receiver receives a signal from a transmitter by at least two antenna beams, and to perform code acquisition, the antenna beams formed are searched at different delays of the spreading code. The number M of antenna beams can also be changed adaptively by determining a signal-to-noise ratio and by forming a number of antenna beams which is proportional to the signal-to-noise ratio. The receiver performs code acquisition by receiving a signal from the transmitter and by searching the antenna beams formed at the different delays of the spreading code.

Abstract: A radio system includes a base station and a remote station. The base station includes a space-time encoder, an antenna system, a transmitter, a base station receiver, and a power management controller. The space-time encoder encodes a stream of symbols into first and second space-time coded signals, and the transmitter transmits the first and second space-time coded signals at respective first and second initial transmit powers from the antenna system so as to form respective first and second radiation patterns. The base station receiver receives power coefficient indicator information from the remote station, and the power management controller determines first and second adjusted transmit powers based on the respective first and second initial transmit powers and the power coefficient indicator information. In an alternative embodiment, a transmit station of a radio system includes a circuit to determine an angular power spectrum, a space-time encoder, and a transmitter.

Abstract: A method of directional radio communication in a wireless communications network between a first station and a second station. The method comprises the steps of transmitting a plurality of communication bursts from the first station to the second station, each of the bursts being substantially continuous and comprising a reference signal having a plurality of reference signal components and a data signal having a plurality of data signal components wherein respective signal components of the reference signal are transmitted in substantially different directions, the data signal components being transmitted in the substantially different directions.

Abstract: A method of selecting radio transmission resources of a first station for communicating between the first station and a plurality of second stations in a wireless communications network. The method comprises the steps of grouping the plurality of second stations based on a traffic characteristic of respective ones thereof, and selecting at the first station radio transmission resources for communication with the second stations such that the transmission resources are used substantially equally within each group.

Abstract: The invention relates to a method of improving radio connection (170) quality in a cellular radio network and a cellular radio network. The cellular radio network comprises a vase station system (126) and subscriber terminals (150). Between the base station system (126) and the subscriber terminal (150) there is a bidirectional radio connection (170) using a directional antenna beam (304, 306). In the method, a direction of arrival (302A) of the antenna beam (304A) directed on the basis of a radio signal (304A) received uplink, transmitted by the subscriber terminal (150) is formed in the base station system (126). The base station system (126) transmits a radio signal (306) downlink to the subscriber terminal (150) in the direction of transmission (308) formed on the basis of the direction of arrival (302A). In forming the direction of transmission (308) a preknown number (L) of previously formed directions of arrival (402, 302C, 302B, 302A) are utilized.

Abstract: A method for directing an antenna beam, and a transceiver which comprises antenna arrays forming antenna beams in the transmission direction, by means of which beams a signal is transmitted, and which receives signals that propagate via different paths to the transceiver. The transceiver comprises estimating means for estimating directions of arrival of the received signals, when the transceiver receives signals propagated via different paths, measuring means for measuring the strengths of the signals received from different paths of arrival, and beam directing means. The directing means command the antenna array to form in the transmission direction the main antenna beam which is formed in the direction wherefrom the strongest signal is received, if the directions of arrival of the received signals differ only slightly from one another.

Abstract: A method of directional radio communication between a first station (6) and a second station, comprising the steps of defining at the first station (6) a plurality of beam directions (b1-b8) for transmitting signals to said second station, each of said beam directions being selectable. A plurality of beam directions are selected at said first station in which a signal is to be transmitted form said first station to said second station. Said signal i transmitted in said plurality of beam directions, whereby the power level of the signal transmitted in each of said selected plurality of beam directions is individually selectable.

Abstract: The invention relates to a radio system comprising transceivers. One of the transceivers comprise, for instance, means for comparing a parameter representing signal quality measured from the received signal with at least one threshold value and means for determining a quality class for the performance of a MIMO common channel. At least one of the transceivers comprises means for storing the observations made by the second transceiver about the quality class transitions of the transfer channel of the first transceiver and means for estimating the next quality class of the transfer channel of the first transceiver from the stored quality class transition observations.

Abstract: The invention relates to a method of performing code acquisition on a signal to be received and to a receiver implementing the method. In the method the receiver receives a signal from a transmitter by at least two antenna beams, and to perform code acquisition, the antenna beams formed are searched at different delays of the spreading code. The number M of antenna beams can also be changed adaptively by determining a signal-to-noise ratio and by forming a number of antenna beams which is proportional to the signal-to-noise ratio. The receiver performs code acquisition by receiving a signal from the transmitter and by searching the antenna beams formed at the different delays of the spreading code.

Abstract: A method of directional radio communication between a first station (BTS4) and a second station (MS) comprises the following steps. A plurality of consecutive signals are received at the first station (BTS4) from the second station (MS). The signals are each receivable from at least one of a plurality of different directions. For each of a plurality of sequential signals which are received by the first station (BTS4) from the second station (MS) the value of at least one parameter is determined. The value of at least one parameter is selected for a signal to be transmitted from the first station (BTS4) to the second station (MS), the value of the at least one parameter of the signal to be transmitted by the first station (BTS4) being selected in dependence on the determined values of the at least one parameter of the plurality of sequential signals.

Abstract: The invention relates to a method and a system for implementing diversity in transmission utilizing orthogonal antenna beams formed using digital beam forming methods. In this method antenna beams (604, 606) are directed to be adjacent so as to set at least one of the estimated directions of arrival (614) of the received signal within the range between antenna amplification maximums (610, 612) of the antenna beams and signal is sent using said antenna beams. An advantage provided by the method and system of the invention is to improve the performance of the system in the downlink direction and also to reduce the imbalance between the uplink performance and the downlink performance. The method of the invention also allows to carry out power control specifically for each antenna beam.

Abstract: The invention relates to a method of transmitting data from a transmitter to a receiver in a radio system, and to a radio system.

Abstract: A method for carrying out code synchronization when a signal has been spread-coded by a pseudo-random spreading code. The method comprises forming angular cells (400, 402, 404, 406, 408, 410), determining interference power in each angular cell (400, 402, 404, 406, 408, 410), arranging the angular cells (400, 402, 404, 406, 408, 410) according to the interference power, carrying out code acquisition by examining the arranged angular cells (400, 402, 404, 406, 408, 410) by using different delays of the spreading code, starting from the angular cell with the lowest interference power. The angular cells (400, 402, 404, 406, 408, 410) can e.g. be arranged as a vector in ascending order according to the interference power. The method comprises determining the number of angular cells to be formed e.g. by means of an estimated interference power.

Abstract: The invention relates to a method of improving the quality of a radio connection (170) in a cellular radio network. Relevant for the invention, the cellular radio network includes a base station system (126) and a subscriber terminal (150). A bidirectional radio connection (170) using a directional antenna beam (304) is provided between the base station system (126) and the subscriber terminal (150). In the method, in the base station system (126) an angle of incidence (302) of the directional antenna beam (304) is formed on the basis of a received radio signal (170A) transmitted by the subscriber terminal (150). The base station system (126) transmits a radio signal (170B) to the subscriber terminal (150) in the direction of an angle of departure (308) formed on the basis of the angle of incidence (302). In accordance with the invention, a ratio is formed for the imbalance between the downlink and uplink traffics.

Abstract: A method of directional radio communication between a first station and a second station comprises the steps of determining from at least one signal received at the first station from the second station which of a plurality of different radio environment types is present between said first and second stations. A signal is transmitted from the first station to the second station with at least one parameter of said transmitted signal being dependent on the determined radio environment type.

Abstract: A method of directional radio communication between a first station and a second station comprises the following steps. A first signal transmitted from the second station is received at the first station. The first signal is receivable from a plurality of different directions. A principle beam direction from which the first signal is received by the first station is determined. A plurality of beam directions for transmitting a radiation beam is defined at the first station. Each of the beam directions is selectable. The determined principle beam direction and at least one other auxiliary beam direction is selected at the first station. The at least one auxiliary beam direction is adjacent to the determined principle beam direction. A second signal is transmitted from the first station to the second station in the selected beam direction.

Abstract: A method for carrying out code synchronization when a signal has been spread-coded by a pseudo-random spreading code. The method comprises forming angular cells (400, 402, 404, 406, 408, 410), determining interference power in each angular cell (400, 402, 404, 406, 408, 410), arranging the angular cells (400, 402, 404, 406, 408, 410) according to the interference power, carrying out code acquisition by examining the arranged angular cells (400, 402, 404, 406, 408, 410) by using different delays of the spreading code, starting from the angular cell with the lowest interference power. The angular cells (400, 402, 404, 406, 408, 410) can e.g. be arranged as a vector in ascending order according to the interference power. The method comprises determining the number of angular cells to be formed e.g. by means of an estimated interference power.

Abstract: A method of directional radio communication in a mobile communication network between a first station and a second mobile station includes the following steps. Signals transmitted by the second station are received at the first station. A parameter representative of the distance between the second station and the first station is monitored. A signal beam is transmitted from the first station to the second station, the angular spread of the signal beam transmitted by the first station being dependent on the distance between the first and second stations.