Communication systems

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.

1 . 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.   
   
   
       2 . The method of  claim 1  comprising controlling one or both of the first and second portions to substantially equalise operational parameters of the first wireless communications system with equivalent operational parameters of the second wireless communications system. 
   
   
       3 . The method of  claim 1  comprising selecting one or both of the first and second portions of spectrum to reduce a level of interference in at least one of the first wireless communications system and the other wireless communications systems, based on levels of interference in the first and second portions. 
   
   
       4 . The method of  claim 1  comprising assigning the first portion of spectrum from the first wireless communications system to a second wireless communications system amongst the one or more other wireless communications systems, and accepting the assignment of the second portion of spectrum from the second wireless communications system to the first wireless communications system. 
   
   
       5 . The method of  claim 1  comprising assigning the first portion of spectrum from the first wireless communications system to a second wireless communications system amongst the one or more other wireless communications systems, and accepting the assignment of the second portion of spectrum from a third wireless communications system amongst the one or more other wireless communications systems to the first wireless communications system, the second and third wireless communications systems being different. 
   
   
       6 . The method of  claim 1  comprising, before the exchange, identifying a high-interference portion of spectrum to serve as the first portion of spectrum. 
   
   
       7 . The method of  claim 6  comprising analysing interference levels in each of a plurality of sub-chunks of spectrum used by the first wireless communications system before the exchange, and identifying the high-interference portion of spectrum by selecting a said sub-chunk associated with a level of interference which is higher than levels of interference associated with other said sub-chunks. 
   
   
       8 . The method of  claim 7  wherein analysing the interference levels comprises each of a plurality of network elements of the first wireless communications system analysing the interference levels in each of a plurality of sub-chunks of the spectrum used by the first wireless communications system before the exchange, and each of the network elements identifying a said sub-chunk associated with a level of interference which is higher than levels of interference associated with other said sub-chunks. 
   
   
       9 . The method of  claim 8  wherein identifying the high-interference portion of spectrum comprises, in the case that the network elements all identify the same sub-chunk, selecting that sub-chunk as the high-interference portion, and, in the case that the network elements identify different sub-chunks, determining a region of spectrum which has the greatest degree of overlap with all of the different sub-chunks and selecting that region as the high-interference portion. 
   
   
       10 . The method of  claim 1  comprising transmitting outgoing signalling specifying the first portion of spectrum as an exchange candidate. 
   
   
       11 . The method of  claim 10  wherein transmitting the outgoing signalling comprises transmitting an exchange request specifying the first portion of spectrum as an exchange candidate in order to trigger the instance of the spectrum assignment process. 
   
   
       12 . The method of  claim 10  comprising transmitting the outgoing signalling following the receipt of an exchange request specifying the second portion of spectrum as an exchange candidate. 
   
   
       13 . The method of  claim 1  comprising receiving incoming signalling specifying the second portion of spectrum as an exchange candidate. 
   
   
       14 . The method of  claim 1  comprising comparing the first and second portions of spectrum before the exchange, and proceeding only if the first portion of spectrum is different to the second portion of spectrum. 
   
   
       15 . The method of  claim 1  comprising, before the exchange, analysing an expected level of interference associated with the second portion of spectrum. 
   
   
       16 . The method of  claim 1  comprising, following the exchange, operating the first wireless communications system to use the second portion of spectrum and to avoid using the first portion of spectrum. 
   
   
       17 . The method of  claim 1  comprising selecting one or both of the first and second portions of spectrum to reduce the number of separate, continuous regions of spectrum used by at least one of the first wireless communications system and the other wireless communications systems. 
   
   
       18 . Apparatus for 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 apparatus comprising
 spectrum assignment circuitry configured to exchange a first portion of spectrum for a second, different portion of spectrum, in a single instance of the spectrum assignment process, 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.   
   
   
       19 . A computer program storage medium comprising a computer readable storage medium and computer program instructions, recorded on the computer readable storage medium, for controlling spectrum use in a first wireless communications system, which, when run on a computer comprising a processor and a memory storing the computer program instructions and forming part of a network element or an external controlling element, causes the computer to perform 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.