Patent ID: 8571468
Filing Date: 2013-10-29
Classification: H04B,H04W

Abstract:
1. A communication system comprising a source apparatus, an intermediate apparatus and a base station, the source apparatus being operable to transmit a communication signal, via the or each intermediate apparatus, to the base station, the base station and the/each intermediate apparatus comprising an indicator derivator operable to derive one or more indicators of the quality of a communication signal received at the base station or at the intermediate apparatus respectively, and wherein the communication system further comprises: i) a controller provided in the base station; ii) an indicator deviator detector operable to detect a change in one said indicator derived by the base station from a desired value, wherein said desired value is the value of the indicator of the quality of the communication signal derived by the base station when the value is at a target value set by the base station and when a measure of a communication signal received at the base station is in balance with a measure of a communication signal received at the intermediate apparatus; iii) an imbalance detector periodically operable to detect an imbalance between one said indicator derived by the base station and one said indicator derived by the intermediate apparatus; iv) a determination unit operable, following the detection of a change by the indicator deviator detector, to determine a required change in the transmit power of the intermediate apparatus that will tend to bring said indicator to said desired value, wherein said determination unit further comprises a request transmitter operable to transmit a request for a change in the transmit power of the intermediate apparatus to the controller, the determination unit being further operable, following detection of an imbalance by the imbalance detector, to determine a required change in the transmit power of the source apparatus that will tend to substantially restore balance between one said indicator subsequently derived by the base station and one said indicator subsequently derived by the intermediate apparatus, wherein said required change in the transmit power of the source apparatus is determined relative to the degree of imbalance detected by said imbalance detector, the controller being further operable, following determination of said change, to issue a command to said source apparatus commanding a change in the transmit power of the source apparatus and if said command is for an increase in transmit power, to monitor said indicator derived by the intermediate apparatus in order to determine if said transmit power of said source apparatus has been changed in accordance with said command, wherein if it is determined that a change in transmit power of the source apparatus has not been carried out in accordance with said command, said controller is operable to prohibit any subsequent increases in transmit power of said intermediate apparatus, and wherein if an increase in transmit power of said intermediate apparatus is prohibited, and if no subsequent imbalance is detected by said imbalance detector, said controller is operable to allow a subsequent increase in transmit power of said intermediate apparatus.