Abstract: A radio communication system has means for improving power control of a communication channel for the transmission of data after an interruption in the transmission. This is done by applying power control in steps of variable size at the start of a transmission, using a large step size initially which is reduced as the power approaches a target value. In one embodiment the step size is reduced when the sign of a power control command reverses, while in another embodiment the step size is reduced after a predetermined time. These techniques reduce the time taken for power control to be established, thereby addressing the problem that data transmissions at the start of a data channel are likely to be corrupted if the power level is too low, or to generate extra interference if the power level is too high.

Abstract: A method of operating a radio communication system uses a random access channel to enable a secondary station to transmit a message to a primary station. The secondary station transmits a preamble to the primary station. After successful receipt of the preamble the primary station transmits a control channel including power control information to instruct the secondary station to adjust the output power of its transmitter. This method ensures that the secondary station transmits at a sufficient power for the message to be received successfully by the primary station, while minimizing interference generated by the transmission.

Abstract: A method of operating a radio communication system uses a random access channel to enable a secondary station to transmit a message to a primary station. The secondary station-transmits a preamble to the primary station. After successful receipt of the preamble the primary station transmits a control channel including power control information to instruct the secondary station to adjust the output power of its transmitter. This method ensures that the secondary station transmits at a sufficient power for the message to be received successfully by the primary station, while minimizing interference generated by the transmission.

Abstract: A radio communication system has a random access channel for the transmission of data (214) from a secondary station to a primary station. Such a channel is intended for use by secondary stations having data (214) to transmit to a primary station while not actually engaged in a call. A secondary station requesting access chooses a signature corresponding to the resource it requires to encode an access preamble (202). It may be known, from a resource availability message (402) broadcast by the primary station, that certain resources are unavailable. In this case the primary and secondary stations dynamically re-assign signatures corresponding to the unavailable resources to available resources, thereby reducing the probability of collisions between different secondary stations requesting the same resource.

Abstract: A method of operating a radio communication system uses a random access channel to enable a secondary station to transmit a message to a primary station. The secondary station transmits a preamble to the primary station. After successful receipt of the preamble the primary station transmits a control channel including power control information to instruct the secondary station to adjust the output power of its transmitter. This method ensures that the secondary station transmits at a sufficient power for the message to be received successfully by the primary station, while minimizing interference generated by the transmission.

Abstract: In a radio communication system having a primary station and a plurality of secondary stations, the power of uplink and downlink channels between the primary station and a secondary station is controlled in a closed loop manner by each station transmitting power control commands to the other station. In response to these commands the receiving station adjusts its output power in steps.

Abstract: In a radio communication system having a primary station and a plurality of secondary stations, the power of uplink and downlink channels between the primary station and a secondary station is controlled in a closed loop manner by each station transmitting power control commands to the other station. In response to these commands the receiving station adjusts its output power in steps. By combining a plurality of received power control commands before adjusting its output power the receiving station may emulate the ability to use a smaller power control step size than its minimum, thereby improving performance under certain channel conditions. In one embodiment when the required power control step size is less than the minimum step size of a particular station, that station processes a group of power control commands to determine whether to adjust its output power by its minimum step size. In an alternative embodiment the power control step size is fixed when the combining algorithm is used.

Abstract: There is disclosed a method of dealing with a computer virus which self-propagates by causing an infected computer to send an email containing the virus to another computer using an email address present in an address book of the infected computer. The method comprises the steps of (i) receiving an email suspected of having been caused to be sent by such a virus at a computer; and (ii) upon step (i), carrying out a computer automated service for dealing with such a virus, wherein the automated service is rendered either to the computer from which the email was sent or to a computer in receipt of the email other than the one in step (i). Also disclosed is a corresponding computer system and related methods.

Abstract: A radio communication system comprises a communication channel for the transmission of data packets from a primary station (100) to a secondary station (110). In response to receipt of a data packet, the secondary station transmits an acknowledgement signal to the primary station indicating the status of the received data packet. The signal is selected from a set of at least two available signal types (for example positive and negative acknowledgements, ACK and NACK), and the power at which it is transmitted depends on the type of the signal.

Abstract: In a radio communication system having a primary station and plurality of secondary stations, power of uplink and downlink channels between the primary station and a secondary station is controlled in a closed loop manner by each station transmitting power control commands to the other station. Responsive to these commands receiving station adjusts its output power in steps. By considering a plurality of received power control commands receiving station may emulate the ability to use power control step sizes other than those it directly implements, for example step sizes smaller than its minimum or intermediate between implemented step sizes. Performance can thereby be improved under certain channel conditions. In one embodiment when required power control step size is less than the minimum step size of the receiving station, that station processes a group of power control commands to determine whether to adjust its output power by its minimum step size.

Abstract: A hierarchical cellular radio communication system comprises a plurality of pico cells (106) and an umbrella macro cell (102), each cell having a controlling primary station (104, 108). A secondary station (110) has a communication channel with the system split into a control sub-channel (212), for the transmission of control information, and a data sub-channel (214), for the transmission of user data. The control sub-channel connects the secondary station to the primary station serving the macro cell while the data sub-channel connects the secondary station to the primary station serving the pico cell.

Abstract: A radio communication system comprises a primary station (100) and at least two secondary stations (110a, 110b), each of which comprises at least one antenna (108, 118). The primary station is arranged to transmit respective communication channels to each of the secondary stations from respective mutually exclusive subsets of its antennas (108). The communication channels are defined solely by the respective subsets of antennas (108), and each secondary station has means (414) for extracting from the received signals the subset comprising its respective communication channel.

Abstract: An internal powerline network is provided with a routing device for routing a signal on only a part of the network. In this way the data capacity of the network is increased. The routing device is advantageously attached to the fuse box of the powerline network.

Abstract: A radio communication system comprises a communication channel for the transmission of data packets (302) from a primary station having a plurality of antennas to a secondary station having at least one antenna. The channel comprises a plurality of paths, and the primary station transmits a plurality of packets substantially simultaneously. Each of the plurality of packets is transmitted via a different subset of the plurality of paths, for example by arranging for each packet to be transmitted via a different antenna or antenna beam.

Abstract: A radio communication system comprises a primary station which is arranged to transmit a series of data packets to a secondary station which operates according to an ARQ scheme for acknowledging correct reception of each packet. The primary station transmits error correction information relating to any packets that are not received correctly, thereby enabling the secondary station to extract correctly the data. The data packets are transmitted via a plurality of logical channels, so that an error in transmission of one packet does not hold up transmission of packets in other channels. Transfer of data transmission from one primary station to another is done by transferring each channel when correct reception of a data packet on that channel has been acknowledged, thereby avoiding the extra signalling required in transferring logical channels in which a data packet has been received in error and the error correction transmissions have not been completed.

Abstract: A radio communication system comprises a secondary station (110) having a plurality of communication channels (226a, 226b, 226c) with a plurality of primary stations (100a, 100b, 100c) for the transmission of data packets from one or more selected primary stations to the secondary station. The selection of primary station(s) is performed on the basis of a plurality of metrics, and may be performed in the secondary station, the primary stations, or shared between primary and secondary stations. Use of a plurality of metrics enables improved system behaviour.

Abstract: A radio communication system comprises a secondary station having a communication channel with a primary station for the transmission of data packets from the primary station to the secondary station. In response to receipt of a data packet, the secondary station transmits a combined acknowledgement and quality parameter signal (402) to the primary station. The signal (402) indicates whether the data packet was received correctly and the value of the quality parameter enables the primary station to select transmission parameters for further data transmissions. A range of formats for the combined signal are possible.

Abstract: A radio communication system comprises a secondary station (110) having a plurality of communication channels (226a,226b,226c) with a plurality of primary stations (100a,100b,100c). Separate closed loop power control is performed for each of the communication channels (226a,226b, 226c). This enables the optimum primary station for transmission of data to the secondary station (110) to be selected. Parameters derived from operation of each power control loop enable optimum setting of channel parameters for each primary station (100a,100b,100c).

Abstract: A radio communication system comprises a communication channel between a transmitter (108) having a plurality of antennas (110) and a receiver (114) having at least one antenna (110). In such a system the communication channel comprises a plurality of paths (112) having a range of characteristics. Data for transmission is generated by one or more applications (102) and has one or more categories assigned to it, for example by the addition of tags by a tagging block (204) indicating its importance or other requirements. Depending on the assigned categories and the characteristics of the paths (112), the data is mapped to one or more of the transmitter's antennas (110) to select a suitable transmission path (112).

Abstract: A radio communication system has improved power control of transmissions between a first station and a second station. The second station adjusts the power of its transmissions to the first station in response to power control commands received from the first station. The first station determines when it has synchronised to transmissions from the second station and informs the second station of synchronisation. After synchronisation has been signalled, the rate of adjustment of transmission power by the second station is increased (508). The changed rate of power control can be achieved by adjustments to the power control step size, or by other modifications to the response of the second station to received power control commands or to its rate of reception of power control commands.