摘要:
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).
摘要:
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).Such an arrangement is particularly suitable for a high speed downlink data service, where the fast selection of the optimum primary station and/or channel parameters improves link robustness and system throughput.
摘要:
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.These techniques overcome the problem that, because synchronisation can take a significant time to be established, there is a danger that transmission power may be increased too much and cause unacceptable interference.
摘要:
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.
摘要:
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. The secondary station receives the plurality of data packets, determines whether each packet is received correctly and signals this determination (typically as an acknowledgement (304) or a negative acknowledgement (306)) to the primary station for each of the plurality of packets. The signaling may be by any convenient means, for example transmitting each acknowledgement or negative acknowledgement via a different subset of available uplink paths.
摘要:
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.
摘要:
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. The invention is applicable to power control in both primary and secondary stations.
摘要:
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.In one embodiment the quality parameter is a site selection signal indicating a preferred subset of primary stations for subsequent data transmissions. In another embodiment the quality parameter relates to the quality of the radio link and enables the primary station to select suitable modulation and coding schemes and/or transmit power levels.
摘要:
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. The invention is applicable to power control in both primary and secondary stations.
摘要:
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 adjusting the transmission power immediately after the interruption by an offset from the power used before the interruption. The offset may be fixed or may be determined from the transmission power in the period before the interruption. This technique reduces, on average, the time taken for power control to be re-established, thereby addressing the problem that data transmissions immediately after the interruption are likely to be corrupted if the power level is too low, or to generate extra interference if the power level is too high.