Communications system

Abstract

A mobile communications system is proposed in which mobile communications devices are arranged to transmit signals to and to receive signals from a base station using one or a subset of available sub-bands, with the base station being configured to move the mobile communications devices between the sub-bands. An anchor sub-band is also provided on which idle mobile communications devices camp until they are moved to one or more other sub-bands in addition to or instead of the anchor sub-band.

1 . A communications device comprising:
 a transceiver operable to transmit downlink data to and to receive uplink data from a remote communications device using a plurality of component carriers; and   a controller operable to control the transceiver so that the communications device transmits broadcast and paging channels on an anchor subset of said component carriers but not on another subset of the component carriers.   
     
     
         2 . A communications device according to  claim 1 , wherein the controller is operable to cause the transceiver to transmit control data to the remote communications device instructing the remote communications device to monitor one or more component carriers in the other subset of component carriers. 
     
     
         3 . A communications device according to  claim 2 , wherein the controller is operable to cause the transceiver to transmit DRX control data to the remote communications device to cause the remote communications device to switch off transceiver circuits for component carriers that it is not monitoring. 
     
     
         4 . A communications device according to  claim 2 , wherein said controller is operable to cause the transceiver to transmit said control data within a MAC layer communication message, a Physical layer communications message or an RRC layer communication message. 
     
     
         5 . A communications device according to  claim 1 , wherein the controller is operable to receive a connection request from the remote communications device on a component carrier of said anchor subset and is operable to cause the transceiver to transmit downlink data for the remote communications device on a different component carrier. 
     
     
         6 . A communications device comprising:
 a transceiver operable to transmit uplink data to and to receive downlink data from a remote communications device on a plurality of component carriers, wherein an anchor subset of the component carriers include broadcast and paging channels; and   a controller operable to control the transceiver so that during an idle mode, the communications device is operable to camp on one or more of the component carriers in the anchor subset.   
     
     
         7 . A communications device according to  claim 6 , wherein the controller is operable to receive control data from the remote communications device instructing the communications device to monitor one or more component carriers in another subset of the component carriers and wherein the controller is operable to control the transceiver to monitor the component carriers in the other subset. 
     
     
         8 . A communications device according to  claim 7 , wherein the controller is operable to receive DRX control data from the remote communications device and wherein the controller is operable to use the received DRX control data to determine when to switch off parts of the transceiver configured for component carriers that are not to be monitored. 
     
     
         9 . A communications device according to  claim 8 , wherein the DRX control data includes an ON duration and a DRC cycle, and wherein the controller is operable to switch off parts of the transceiver that are not to be monitored during the On durations defined by the DRX control data, 
     
     
         10 . A communications device according to  claim 8 , wherein said DRX control data includes control data in respect of each component carrier and defines times during which transceiver circuitry for the different component carriers can be switched off. 
     
     
         11 . A communications device according to  claim 7 , wherein said controller is operable to receive said control data within a MAC layer communication message, Physical layer message or RRC layer message. 
     
     
         12 . A communications device according to  claim 6 , wherein the controller is operable to transmit a connection request on the component carrier on which the device is camped and is operable to receive downlink data from the remote communications device on a different component carrier that the communications device has been instructed to monitor. 
     
     
         13 . A communications device according to  claim 6 , wherein the controller is operable to switch off parts of the transceiver for component carriers on which the communications device is not camped. 
     
     
         14 . A communications device comprising:
 a transceiver operable to transmit downlink data to and to receive uplink data from a remote communications device using a subset of component carriers; and   a controller operable to control the transceiver so that:
 i) during a first interval the communications device is operable to communicate with the remote communications device on a first subset of component carriers; 
 ii) the communications device transmits control data to the remote communications device using the first subset of component carriers, the control data instructing the remote communications device to communicate with the communications device using a second subset of component carriers; and 
 iii) during a second interval the communications device is operable to communicate with the remote communications device on the second subset of component carriers. 
   
     
     
         15 . A communications device comprising:
 a transceiver operable to transmit uplink data to and to receive downlink data from a remote communications device using a subset of component carriers; and   a controller operable to:
 i) control the transceiver so that during a first interval the communications device is operable to communicate with the remote communications device on a first subset of component carriers; 
 ii) receive control data from the remote communications device using the first subset of component carriers, the control data instructing the communications device to communicate with the remote communications device using a second subset of component carriers; and 
 iii) control the transceiver so that during a second interval the communications device is operable to communicate with the remote communications device on the second subset of component carriers. 
   
     
     
         16 . A communications device according to  claim 14 , wherein the control data instructing use of the second subset of component carriers is provided in a MAC layer message, a Physical layer communications message or an RRC layer communication message. 
     
     
         17 . A communications device according to  claim 15 , wherein the controller is operable to switch off parts of the transceiver for component carriers not included in the subset that is to be used for communicating with the remote communications device. 
     
     
         18 . A communications device according to  claim 17 , operable to receive DRX control data from the remote communications device and wherein the controller is operable to switch off parts of the transceiver for component carriers not included in the subset that is to be used for communicating with the remote communications device in dependence upon the received DRX control data. 
     
     
         19 . A communications device according to  claim 18 , wherein the DRX control data includes an ON duration and a DRX cycle, and wherein the controller is operable to switch off parts of the transceiver that are not to be monitored during the On durations defined by the DRX control data, 
     
     
         20 . A communications device according to  claim 18 , wherein said DRX control data includes control data in respect of each component carrier and defines times during which transceiver circuitry for the different component carriers can be switched off. 
     
     
         21 . A method performed by a communications device comprising:
 transmitting downlink data to and receiving uplink data from a remote communications device using a plurality of component carriers; and   controlling a transceiver so that the communications device transmits broadcast and paging channels on an anchor subset of said component carriers but not on another subset of the component carriers.   
     
     
         22 . A method performed by a communications device comprising:
 transmitting uplink data to and receiving downlink data from a remote communications device on a plurality of component carriers, wherein an anchor subset of the component carriers include broadcast and paging channels; and   controlling a transceiver so that during an idle mode, the communications device camps on one or more of the component carriers in the anchor subset.   
     
     
         23 . A method performed by a communications device comprising:
 transmitting downlink data to and receiving uplink data from a remote communications device using a subset of component carriers; and   controlling a transceiver so that:
 i) during a first interval the communications device communicates with the remote communications device on a first subset of component carriers; 
 ii) the communications device transmits control data to the remote communications device using the first subset of component carriers, the control data instructing the remote communications device to communicate with the communications device using a second subset of component carriers; and 
 iii) during a second interval the communications device communicates with the remote communications device on the second subset of component carriers. 
   
     
     
         24 . A method performed by a communications device comprising:
 transmitting uplink data to and receiving downlink data from a remote communications device using a subset of component carriers; and   controlling a transceiver:
 i) so that during a first interval the communications device communicates with the remote communications device on a first subset of component carriers; 
 ii) to receive control data from the remote communications device using the first subset of component carriers, the control data instructing the communications device to communicate with the remote communications device using a second, different, subset of component carriers; and 
 iii) so that during a second interval the communications device communicates with the remote communications device on the second subset of component carriers. 
   
     
     
         25 . A non-transitory computer readable recording medium comprising computer implementable instructions for causing a programmable computer device to become configured as the communications device of any of  claim 1 .