Cellular Communication System, a Base Station and a Method of Resource Allocation
A cellular communication system ( 100 ) comprises a network controller ( 113 ) having a first resource allocator ( 117 ) for allocating codes to a first set of calls in a cell. The network controller ( 113 ) is coupled to a base station ( 109 ) which comprises a second resource allocator ( 119 ) for allocating codes to a second set of calls in the cell. The first resource allocator ( 117 ) and the second resource allocator ( 119 ) share a code tree associated with the cell. The base station ( 109 ) comprises a code tree processor ( 209 ) that determines which codes are allocated by the first resource allocator ( 117 ) in response to call event signalling received from the network controller ( 113 ). The call event signalling may be related to a call setup, a call termination, a call handover and/or a call admission characteristic. The second resource allocator ( 119 ) allocates codes in response to the codes allocated by the first resource allocator ( 117 ) and in particular may allocate only codes not used by the first resource allocator ( 117 ).
1 . A cellular communication system comprising:
a network controller comprising a first resource allocator for allocating codes to a first set of calls in a cell from a code tree associated with a cell;
a base station coupled to the network controller and comprising a second resource allocator for allocating codes to a second set of calls in the cell from the code tree associated with the cell; wherein
the base station comprises means for determining codes allocated by the first resource allocator in response to call event signalling received from the network controller; and
the second resource allocator is operable to allocate codes in response to the codes allocated by the first resource allocator.
2 . A cellular communication system as claimed in claim 1 wherein the means for determining codes allocated by the first resource allocator is operable to determine a subset of the code tree used by the first resource allocator and the second resource allocator is operable to allocate only codes not belonging to the subset.
3 . A cellular communication system as claimed in claim 1 wherein the call event signalling comprises signalling for a plurality of call events; and the means for determining codes allocated by the first resource allocator is operable to designate a code of the code tree as unavailable for the second resource allocator in response to call event signalling for a single call event.
4 . A cellular communication system as claimed in claim 3 wherein the call event signalling comprises an indication of a code allocation by the first resource allocator associated with the single call event.
5 . A cellular communication system as claimed in claim 1 wherein the call event signalling comprises at least one of the group of; call setup signalling, handover signalling, and call termination signalling.
6 . A cellular communication system as claimed in claim 1 further comprising means for designating a first subset of the code tree as allocated to the first resource allocator and a second subset of the code tree as allocated to the second resource allocator.
7 . A cellular communication system as claimed in claim 1 wherein the first resource allocator is operable to temporarily allocate codes of the second subset to the first set of calls.
8 . A cellular communication system as claimed in claim 7 wherein the first resource allocator is operable to allocate codes of the second subset in response to at least one of the group of; a buffer loading associated with the second set of calls, a delay associated with the second set of calls, a throughput associated with the second set of calls, and a call admission characteristic associated with the second set of calls.
9 . A cellular communication system as claimed in claim 8 wherein the network controller comprises means for determining an increased code requirement of the second subset by the second resource allocator and the first resource allocator is operable to terminate a call of the first set of calls having a code allocated of the second subset in response to the determination of the increased code requirement.
10 . A method of resource allocation in a cellular communication system, the method comprising:
a first resource allocator of a network controller allocating codes to a first set of calls in a cell from a code tree associated with the cell;
at a base station determining codes allocated by the first resource allocator in response to call event signalling received from the network controller; and
a second resource allocator of a base station allocating codes to a second set of calls in the cell from the code tree associated with the cell in response to the codes allocated by the first resource allocator.