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. 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).

Abstract: A radio communication system comprises a primary station (100) for transmitting information signals on a downlink channel (122) and for receiving signals from one or more secondary stations (110) on an uplink random access packet channel (RACH) (124), the downlink and uplink channels being independent of each other. Power control is applied to the transmitted downlink signals by at least one of the secondary stations transmitting indicia indicating the prevailing radio channel characteristics of the uplink channel, the indicia being used by the primary station to apply power control to the downlink signals. If the uplink signals are CDMA signals the indicia may comprise a timing offset which has a value related to the quantity to be signalled.

Abstract: A secondary station has a receiver capable of resolving signals received as a plurality of multipath signals from a plurality of base stations during a soft handover process. This capability may, for example, be provided by a Rake receiver. In order to decode and act upon the received signals in a very short period of time, signals (402g,402h) arriving after a predetermined time are not processed by the receiver which is able instead to process weaker signals (402d,402e) which arrived before the time (t1). Such a secondary station is particularly suitable for decoding and acting upon power control commands included in received signals in a UMTS system, for which a very limited period of time is provided by the UMTS specification. In this application the predetermined time (t1) is the time after which signals are received too late for use in determining the next power control change.

Abstract: A radio communication system has means for enabling the control channels associated with a data channel transmitting packet data with a low duty cycle to be switched to a dormant state or interrupted entirely. This reduces the excessive overhead that such control channels represent on a data channel only using a small proportion of the available channel capacity.

Abstract: A radio communication system includes a communication channel for the transmission of data packets from a primary station to a secondary station. In operation, on detection of a data packet, the secondary station transmits an acknowledgement signal to the primary station to indicate the status of the received data packet, and resets a timer. While the timer is running, the secondary station modifies a characteristic of uplink transmissions. In one embodiment the modification includes the secondary station transmitting a negative acknowledgement for each time at which a data packet could have been transmitted if no indication of a data packet is received. In another embodiment the modification includes the secondary station altering a parameter relating to transmission of channel quality information to the primary station.

Abstract: The invention provides a method of conformance testing of a secondary station for use in a radio communication system which permits a soft handover process in which the secondary station engages in communication with a plurality of primary stations. The method permits testing the response of the secondary station to power control commands received simultaneously from each of the plurality of primary stations instructing it to adjust its output transmission power. In particular, the method enables testing the secondary station's assessment of the reliability of the power control commands received from each primary station, which has not been possible previously. The test is performed by transmitting known sequences of power control commands to the secondary station from each of the primary stations, then comparing the actual pattern of changes in output transmission power with the expected pattern of changes.

Abstract: A method and apparatus for transferring information over a communications link includes transmitting information at a first power level, monitoring for correct reception of the transmitted information and transmitting further information at a second, power level other than that used for the original transmission if correct reception did not occur. The further information allows the content of the originally transmitted information to be established and in one embodiment constitutes a retransmission of the originally transmitted information. By retransmitting at a different power level the probability of correct reception may be enhanced, especially when the communications link is wireless. The first and second transmission power levels are governed using closed loop power control such that transmission power level is controlled to achieve a required quality of reception parameter at the receiving end of the link. In one arrangement the quality or reception parameter is the signal-to-interference ratio.

Abstract: A radio communication system has means for ensuring that power control of a communication channel has been established before the transmission of data. This is done by delaying initial transmission of a data channel (either at the start of a transmission or after a pause) until after the initial transmission of control channels. In one embodiment the transmission of a data channel can be delayed until adequate power control has been established. These techniques overcome the problem that data transmissions at the start of a data channel are likely to be corrupted if their power level is too low, or to generate extra interference if their power level is too high.

Abstract: A radio communication system comprising a primary station and a plurality of secondary stations has a communication channel for the transmission of information from a secondary station to the primary station. The secondary station can adjust its output transmission power at a plurality of different rates, and the primary station can instruct the secondary station which of the plurality of rates it should use. The primary station determines the optimum rate for the secondary station to use by measurement of characteristics of signals received from the secondary station, for example the average signal to interference ratio, and instructs the secondary station accordingly. Other indication may be used to determine or verify the optimum rate, for example further properties of the received signals or information on the speed of the secondary station.

Abstract: A radio communication system a primary station and a secondary station operating according to two (or more) two-way communication modes. An uplink and/or a downlink communication channel is present for the first mode, but only one of an uplink and a downlink channel is present for the second mode. Modifications to the protocols of the first and second modes enable the traffic for an absent communication channel of one mode to be carried by the corresponding channel of the other mode.

Abstract: A cellular radio communication system operating in accordance with a time division multiple access protocol assigns different fractional loading factors to different time slots. As a result, as well as because of the effects of local propagation conditions, different time slots will have different interference levels. A mobile station in a worst-case propagation environment (such as near the edge of a cell or when subject to severe shadowing fading) can be assigned a time slot having a low interference level, while a mobile station in a good propagation environment can be assigned a time slot having a higher interference level.

Abstract: A communication system includes first and second terminals which are able to communicate control messages to each other. One of the terminals can reconfigure itself by a process of service negotiations with the other terminal where the capabilities of the reconfigurable terminal are provided to the other terminal. Each of the terminals has a transceiver, a memory for storing software functions, and a processor for controlling the operation of the terminal in accordance with stored software functions. At least one of the software functions is alterable in response to the receipt of a control message containing the new software function plus interface software required by the processor in building a new function into an actual implementation on the terminal. The communication system may be a cordless and/or cellular telephone system where messages are sent over-the-air, or a corded system where messages are relayed by landline.

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 the 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 range of time offsets relative to the boundary (302) of their time slot, 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).

Abstract: A radio communication system has a random access channel for the transmission of data from a secondary station to a primary station while the secondary station is not engaged in a call. A secondary station wishing to use a random access channel resource transmits a preamble encoded with a signature corresponding to the required resource. In response the primary station can transmit a positive acknowledgement (ACK) corresponding to the received preamble, indicating that a channel is available, or a negative acknowledgement (NACK), indicating that the resource is not available. A first set of signatures are used to encode ACKs and a second set of signatures are used to encode NACKs. The two sets of signatures have the property that no signature in one set is the inverse of a signature in the other set, thereby avoiding the possibility of simultaneously transmitting an ACK and a NACK with signatures that are the inverse of one another.

Abstract: A radio communication system includes 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 signaling 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 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 problem with known systems of this type is that a secondary station requesting access also specifies which of a plurality of resources it wishes to access. If that resource is busy access is denied, even if other suitable channels are available. In the present system allocation of a channel is performed by the primary station when acknowledging (206,210) a secondary station's access attempt (202,208), thereby eliminating wasted attempts. In one embodiment the primary station also periodically broadcasts a short message indicating the availability of channels for access attempts.

Abstract: A method and apparatus for transferring information over a communications link includes transmitting information at a first power level, monitoring for correct reception of the transmitted information and transmitting further information at a second-, greater power level than that used for the original transmission if correct reception did not occur. The further information allows the content of the originally transmitted information to be established and in one embodiment constitutes a retransmission of the originally transmitted information. By retransmitting at a greater power level the probability of correct reception is enhanced, especially when the communications link is wireless. A transmitter employing the present invention may offer reduced power consumption since the transmission power level used for the original transmission may be lower than that used by a transmitter not benefiting from the present invention.

Abstract: A method of transferring information in units over a wireless digital communications link between a transmitting station and a receiving station comprising the steps of: transmitting first information units at a first energy level; monitoring if correct reception of the transmitted units occurred; and transmitting second information units associated with the first information units, for which first information units the monitoring did not indicate correct reception occurred, at second energy levels, the second information units allowing the content of the first information units to be established, wherein at least one of the associated second information units is transmitted at an energy level which is selected at least partly so as to minimise the total transmitted energy when averaged over a series of first information unit transmissions with respective second information unit transmissions.

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: The invention relates to a radio communication system in which secondary stations (110) can request services from a primary station (100) using a random access channel employing a time division multiple access protocol, An access request comprises an access packet (200) having a predetermined maximum data capacity. If a secondary station requires to transmit an access request including more payload data (202,206) than can be accommodated in a single access packet the data is subdivided into a plurality of parts each of which is transmitted in a separate access packet. The primary station combines the data from the plurality of access packets (200) forming the access request, and issues an acknowledgement to the secondary station.