Abstract: A wireless sensor network having mobile sensors (64, 65) is provided with a mobile sink (70). To re-position the sink, candidate sink positions are found using information from the sensors. The candidate sink locations are then assessed to give a measure of their suitability to act as the new permanent position. To do this, the sink moves to each of the candidate positions in turn and obtains data and/or signals from the sensors (64, 65) within range to estimate a total throughput expected if the sink is located at that position. The sink then transfers to the most suitable candidate position permanently, until the dynamic repositioning process is triggered again. In this way it is possible to achieve a better performance than if only the centre of gravity of the sink range is taken into account to position the sink.

Abstract: An interference mitigation method in a wireless network in which a plurality of nodes share an available frequency spectrum by performing wireless communication on sub-channels defined within the available spectrum. The nodes are grouped into clusters, each cluster having a leader of the cluster. Preferably, every node in the cluster is a transceiver equipped to act as leader and this leader role is rotated around the cluster.

Abstract: Controlling spectrum use in a first wireless communications system which takes part in a spectrum assignment process, in which one of the first wireless communications system and a second wireless communications system assigns a portion of spectrum to the other of the first and second wireless communications system. The first wireless communications system includes a plurality of network elements some or all located within a cell associated with a particular network element of the second wireless communications system.

Abstract: A method of controlling spectrum use in a first wireless communications system which is operable to take part in a spectrum assignment process involving a plurality of wireless communications systems including the first wireless communications system, in which spectrum assignment process one of the said wireless communications systems assigns a portion of spectrum to at least one of the other said wireless communications systems. The method comprising effecting an instance of the spectrum assignment process in response to a trigger which is based on network conditions.

Abstract: A wireless communication system is comprised of multiple radio access networks—RANs—which at least partly share the same frequency spectrum. Each RAN is provided with a gateway—GW—(GW1, GW2, GW3) for managing the network. Spectrum sharing in the system is achieved through a hierarchy of processes including long-term—LT—spectrum assignment, short-term—ST—spectrum assignment, and dynamic channel allocation, the latter process assigning sub-channels to base stations (BS1, . . . BS5; BS6, . . . BS10; BS11, . . . BS16) in each RAN. However, so-called “red” sub-channels (subject to interference) are liable to arise.

Abstract: A method of controlling spectrum use in a first wireless communications system, the first wireless communications system being operable to take part in a spectrum assignment process involving at least the first wireless communications system and one or more other wireless communications systems, the method comprising in a single instance of the spectrum assignment process, exchanging a first portion of spectrum for a second, different portion of spectrum, by assigning the first portion of spectrum from the first wireless communications system to the one or more other wireless communications systems and accepting the assignment of the second portion of spectrum from the one or more other wireless communications systems to the first wireless communications system.

Abstract: A method of, and apparatus for, reducing interference inflicted by a first wireless communications system on a second wireless communications system, and a method of, and apparatus for, interacting with a first wireless communications system.

Abstract: A method of reducing interference in a first wireless communications system, the first wireless communications system being operable in use to take part in a spectrum assignment process involving at least a second wireless communications system, the method comprising defining an exclusion zone in proximity to the first wireless communications system, the exclusion zone indicating that any mobile communications apparatus located within the exclusion zone is not permitted to communicate with the second wireless communications system using a portion of spectrum which was pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system as part of the spectrum assignment process; and varying the local size of a part only of the exclusion zone in dependence on a level of interference inflicted on the first wireless communications system.

Abstract: A method of reducing interference in a first wireless communications system, the first wireless communications system being operable in use to take part in a spectrum assignment process involving at least a second wireless communications system, the method comprising defining an exclusion zone in proximity to the first wireless communications system, the exclusion zone indicating that any mobile communications apparatus located within the exclusion zone is not permitted to communicate with the second wireless communications system using a portion of spectrum which was pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system as part of the spectrum assignment process; and dynamically varying the size of the exclusion zone in dependence on a level of interference inflicted on the first wireless communications system.

Abstract: A spectrum-assignment method for use in a wireless communication system, wherein the system comprises at least a group of communication apparatuses, and wherein each such communication apparatus has a portion of communication spectrum pre-assigned to it for communication, and wherein one of the communication apparatuses of the group is a leader of the group, the method comprising: on a dynamic basis and within the leader of the group, controlling re-assignments of said spectrum between communication apparatuses of the system involving at least one said communication apparatus of the group in dependence upon spectrum requirements of those communication apparatuses, so as to tend to improve spectrum utilization between those communication apparatuses.

Abstract: A spectrum-assignment method for use in a wireless communication system, the system comprising at least first and second communication apparatuses each having a portion of communication spectrum pre-assigned to it for communication, the method comprising: on a dynamic basis, controlling re-assignments of said spectrum between the first and second communication apparatuses in dependence upon spectrum requirements of those apparatuses and at least one indicator indicative of interference expected to result from such re-assignments, so as to tend to improve spectrum utilization between the first and second communication apparatuses.

Abstract: Soft handover techniques are disclosed for use in a system comprising a base station and a plurality of user equipments. The amount of data in the data buffer of each of the user equipments is determined, the amount of data in the data buffers is compared to obtain a relative indicator, the relative indicator indicating how full a user equipment's data buffer is in comparison to the data buffers of the other user equipments, and a base station is selected as an active base station in dependence on the relative indicator.

Abstract: A transmitter 100 transmits an orthogonal frequency division multiplexing (OFDM) signal. A control unit 104 receives a group of input symbols (X0 to XN-1) based on which the transmitted signal is to be generated. The control unit selects, from among a plurality of available allocations of input symbols to sub-carriers, one allocation to apply to the received group of input symbols. Each available allocation serves to allocate the input symbols to respective sub-carriers in a different way from each other available allocation. The allocation selection is based on predicted values of a predetermined property, e.g. a peak-to-average power ratio (PAPR), of the transmitted signal for different available allocations. The available allocations may be different rotations. Further elements 102, 14, 16 of the transmitter generate the transmitted signal using the selected allocation.

Abstract: A method of transmitting data packets in an uplink from a plurality of source user equipments to a base station, the data packets being for onward transmission to a plurality of destination user equipments, is disclosed. The method comprising the steps of determining a measure of a quality of service from the base station to a destination user equipment, and scheduling uplink transmissions from the source user equipments to the base station in dependence on the measure of a quality of service.

Abstract: A transmitter for use, for example, in an OFDM communication system transmits a plurality of signals simultaneously to one or more receivers. Each signal carries data. At the transmitter, a suitable phase vector is selected from among a plurality of available phase vectors to apply to the plurality of signals. Each available phase vector comprises a plurality of phase elements each of which corresponds to one or more of said signals and sets a phase adjustment to be applied by the transmitter to the corresponding signal(s). The suitability of each available phase vector may be judged based on a peak-to-average power ratio reduction achievable by applying the phase vector concerned to the plurality of signals. The selection of the suitable phase vector is initially limited to phase vectors belonging to a first set of the available phase vectors, and is expanded to further phase vectors outside said first set when no suitable phase vector is found in the first set.

Abstract: A method of selecting an active base station during soft handover is disclosed. The active base station is for receiving data from a source user equipment for onward transmission to a destination user equipment. The method comprises determining a measure of a quality of service from the base station to the destination user equipment, and selecting the base station as an active base station based on the measure of the quality of service.

Abstract: A method of scheduling uplink transmissions from a plurality of source user equipments to a base station is disclosed. The method comprises the steps of determining the amount of data in the data buffer of each of the user equipments, comparing the amount of data in the data buffers of the user equipments to obtain, for each user equipment, a relative indicator, the relative indicator indicating how full that user equipment's data buffer is in comparison to the data buffers of the other user equipments, and scheduling uplink transmissions in dependence on the relative indicators. In this way, each user equipment is given some knowledge of the state of the buffer in the other user equipments. The user equipments are therefore able to make more efficient scheduling decisions. This can improve the throughput and give lower packet delivery delays.

Abstract: Packet scheduling apparatus schedules packets of data for transmission from a transmitter such as a Note B to a plurality of receivers such as a plurality of UEs via at least one channel, for example in a high-speed downlink packet access system (HSDPA). A first measures producing unit produces first measures of scheduling performance in at least two different aspects. A decision unit employs a weighted combination of the first measures to decide the receiver(s) to which packets are to be transmitted. The weighted combination is produced by combining the first measures according to respective corresponding weights. A second measures producing unit produces at least one second measure of scheduling performance. A classifying unit classifies the weights for the or each second measure into at least two different classes of weights according to a probable influence the weight is expected to have on the second measure concerned.

Abstract: A packet scheduling method is used to schedule packets of data for transmission from a transmitter via at least one channel to a plurality of receivers, for example in a high speed downlink packet access system of a wireless communications network. Weightings are assigned to at least two different aspects of scheduling performance, for example quality of service, delay and fairness. For each individual receiver at least one combined measure of the scheduling performance in the different aspects is produced according to the assigned weightings. The respective combined measures for different receivers are employed to decide the receiver(s) to which packets are to be transmitted. The weightings may be adjusted by an operator of the transmitter or be adjusted automatically based on the scheduling performance.