摘要:
A method of operating a communications system which comprises a communication station (UE1) and a further station (BS), the stations having means (26, 10) whereby they can communicate with each other, and the communication station having buffer memory means (BUF1 to BUFn) for storing data units in at least one queue. One of the stations (UE1, BS) has means (36) for estimating the transmission delay of at least one of the data units in the at least one queue, and means (30) responsive to the estimated transmission delay exceeding a threshold value for requesting permission from the further station (BS) to enable the communication station (UE1) to transmit at least one data unit to the further station (BS). The further station (i.e. the base station) will either “grant” the permission (in the form of an acceptance of using a certain rate, to transmit to a certain power level, or to transmit for a certain period of time).
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.
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 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. By enabling access requests (202) to be transmitted with a greater range of possible signatures, a much greater number of degrees of freedom is available to a secondary station requesting access to a random access channel. This enables significantly improved efficiency of resource allocation by increasing the amount of information transmitted to the primary station by the access request (202).
摘要:
In a mobile communication system comprising a base station (100) and a plurality of mobile stations (200) and operating closed loop transmitter power control, power control commands for transmission on an uplink are derived from measurements made on received downlink signals comprising nonpredetermined data values. Optionally the non-predeterrnined data values may comprise power control commands for uplink transmit power control.
摘要:
A communication system comprises a downlink indicator channel (DL1) for the transmission of a indicator signal (302) indicating that a data packet (202) is scheduled to be transmitted on a downlink data channel (DL2) from a primary station to a secondary station. In operation, on detection of the indicator signal, the secondary station transmits a status signal, for example a negative acknowledgement signal (204), on an uplink channel (UL) to the primary station immediately before transmission of a positive (206) or negative acknowledgement signal to indicate the status of the received data packet. By providing the primary station with two chances to detect the case where the secondary station fails to detect the indicator signal, peak power requirements of the uplink channel can be reduced, thereby reducing system interference levels.
摘要:
A communication system comprises a downlink data channel for the transmission of data packets from a primary station to a secondary station and two uplink control channels, a first channel for transmission of status signals to indicate the status of received data packets and a second channel for transmission of pilot information. In operation, on detection (402) of a data packet the secondary station increases (404) the transmission power of the second channel, thereby enabling the primary station to obtain a better estimate of uplink channel properties and hence increase the accuracy with which it can decode the status signal. The secondary station transmits (406) the status signal, typically either an acknowledgement (ACK) or negative acknowledgement (NACK), and decreases (408) the transmission power of the second control channel signal. The increase and decrease in power are not necessarily identical, for example as a result of the effects of power control.
摘要:
A mobile station (100), when performing soft handover between base stations (200), receives transmit power control commands from each base station (200). The mobile station (100) determines the reliability of each received transmit power control command by measuring its amplitude relative to a reliability threshold, and combines the power control commands to determine how to adjust its transmit power. The reliability threshold is dependent on the number of base stations (200), or the number of “up”and/or “down” commands received over a time period, or a function of a measured characteristic of received signals. Equivalently, instead of varying the threshold, the amplitude of the power control commands may be scaled, where the scaling factor is dependent on the number of base stations (200), or the number of “up” and/or “down” commands received over a time period, or a function of a measured characteristic of received signals. The reliability threshold, or scaling factor, may be different for commands from each different base station (200).
摘要:
In a radio communication system (50) employing closed loop power control a primary station (100) adjusts its transmit power in response to control information including power control commands received from a secondary station (100). If the primary station (100) fails to obey the power control commands the secondary station modifies the control information and the primary station (100) uses the modified control information to adapt a characteristic of a transmission.
摘要:
A system (50) for communicating data packets from a first station (100) to a destination (400) via at least one of a plurality of second stations (200) which are coupled to the destination (400), in which the second stations (200) acknowledge receipt of the data packets. The first station (100) decides whether to retransmit a data packet or to proceed with transmitting the next data packet, the decision being dependent on receiving a plurality of positive acknowledgements or a plurality of negative acknowledgements.