| 摘要 |
A satellite cellular radio-communication system using beam formation is provided. The satellite cellular radio-communication system includes a satellite, at least one satellite access station, terminals, at least one control unit of a virtual cell. A terminal is configured to transmit and receive on a transmission channel having at least two frequency and spatial transmission resources of a same virtual cell that are different by their frequency band, a frequency and spatial transmission resource being a sub-band of a frequency band used in a beam, the frequency band being taken from among a predetermined number of frequency bands and having been allocated to said beam according to a reuse function. A method for changing transmission resources within a same virtual cell during a communication of a terminal and a method for changing transmission resources with switching from a first virtual cell to a second virtual cell during switching of a terminal in a satellite cellular radio-communications are also provided. |
| 主权项 |
1. A method for changing transmission resources within a same virtual cell during a communication of a terminal in a satellite cellular radio-communications system comprising a transparent communication satellite, serving as a relay, placed in a geostationary orbit or a highly inclined elliptical orbit, at least one satellite access station, transmitting and receiving, configured to transmit and receive service and signal messages to and from the satellite on a first bidirectional wireless way, a set of user terminals configured to receive and transmit the service and signal messages from and to the satellite on a second bidirectional wireless way, the second bidirectional wireless way being made up of a second outbound downlink and a second inbound uplink and at least one control unit of a virtual cell connected to one or more satellite access stations, a virtual cell being a set of frequency and spatial transmission resources, the method comprising the steps of:
performing a wide band measurement of the transmission quality of each sub-band of the virtual cell, the terminal previously attached to a virtual cell having a first list of frequency sub-bands used in the virtual cell; sending, from the terminal to the control unit of the virtual cell, through a first channel using one or more sub-bands of the virtual cell, a first message containing information representative of the quality of each sub-band administered by the control unit of the virtual cell; using the control unit to determine, from the quality information of the sub-bands of the current virtual cell and a second list of free channels of the virtual cell, the transmission parameters of a second channel comprising one or more sub-bands that corresponds to wireless reception conditions that are more favorable than those of the first channel, when such a second channel exists; when a second channel exists, using the control unit to reserve the one or more sub-bands of the second channel, and to prepare and send a second message to the terminal containing identification information of the one or more new sub-bands of the second transmission channel, and an order to switch from the first channel to the second channel; and after receiving and decoding the second message, using the terminal to execute the order to switch from the first channel to the second channel and to send the satellite any new message using the one or more reserved sub-bands used by the second channel. |
