WE CLAIM:
1. A baseband signal processing cluster (100) associated to a first radio cell cluster of a wireless communication network, the first radio cell cluster comprising a first plurality of remote radio heads, the baseband signal processing cluster (100) comprising:
a plurality of baseband signal processing units (110) and at least one unit-specific processing resource management entity (120) operable to manage a processing resource allocation within an associated baseband signal processing unit (110);
an intra-cluster processing resource management entity (130) coupled to the at least one unit-specific processing resource management entity (120) and operable to manage a processing resource allocation among the plurality of baseband signal processing units (110), wherein the intra-cluster processing resource management entity (130) comprises an information management entity (132) operable to determine available baseband signal processing resources of the baseband signal processing cluster (100) based on unit-specific load status information (502) provided from the unit-specific processing resource management entities (120) of the plurality of baseband signal processing units (110), and a decision entity (134) operable to assign a user-specific baseband signal processing task to one or more baseband signal processing units (110) of the baseband signal processing cluster (100) based on a comparison of the unit-specific load status information (502) a required processing resource capacity for the user-specific baseband signal processing task; and
an inter-cluster processing resource management entity (140) is coupled to the intra-cluster processing resource management entity (130) and is operable to exchange information with at least one remote inter-cluster processing resource management entity of a remote baseband signal processing cluster associated to a second radio cell cluster comprising a second plurality of remote radio heads to effect a remote processing resource allocation,
wherein the intra-cluster processing resource management entity (130) is operable to forward a user-specific baseband signal processing request (506) from a baseband signal processing unit (110) to the inter-cluster processing resource management entity (140) for initializing a remote processing resource allocation within at least one remote baseband signal processing cluster, if available processing resources of the baseband signal processing cluster (100) are not sufficient for the user-specific specific baseband signal processing request (506).

2. The baseband signal processing cluster (100) according to claim 1, wherein the intra-cluster processing resource management entity (130) is operable to receive a user-specific specific baseband signal processing request (628) via the inter-cluster processing resource management entity (140) to initialize an allocation of one or more baseband signal processing units (110) having sufficient available processing capabilities for performing user-specific baseband signal processing for a user associated to a remote baseband signal processing unit of a remote baseband signal processing cluster.
3. The baseband signal processing cluster (100) according to claim 1, wherein the intra-cluster processing resource management entity (130) is operable to provide a network address of an allocated baseband signal processing unit (110) having sufficient available processing capabilities for performing user-specific baseband signal processing for a user associated to a remote baseband signal processing unit of a remote baseband signal processing cluster, a network address of said remote baseband signal processing unit, and an identifier of said user to a network router (180) and/or the inter-cluster processing resource management entity (140) of baseband signal processing cluster (100).
4. The baseband signal processing cluster (100) according to claim 1, wherein the inter-cluster processing resource management entity (140) comprises:
an information management entity (142) operable to access information on available processing resources of the baseband signal processing cluster (100), the information comprising information on a baseband signal processing unit (110) having the maximum available processing capacity of the baseband signal processing cluster (100); and
a decision entity (144) operable to determine, based on the information on the available processing resources (504), a remote baseband signal processing cluster having sufficient processing resources available according to a user-specific baseband signal processing request (506; 508) from baseband signal processing cluster (100), if available processing resources of the baseband signal processing cluster (100) are not sufficient for said user-specific baseband signal processing request (506; 508).

5. The baseband signal processing cluster (100) according to claim 1, wherein the inter-cluster processing resource management entity (140) is operable, in response to a received user-specific baseband signal processing request (618) from a remote baseband signal processing cluster, to access information (620) on available processing resources of the baseband signal processing cluster (100), and to acknowledge (642) the received user-specific baseband signal processing request (618) in case of sufficient available processing resources or to reject the received user-specific baseband signal processing request (618) otherwise.
6. The baseband signal processing cluster (100) according to claim 1, wherein the inter-cluster processing resource management entity (140) is operable to forward (628) a received user-specific baseband signal processing request (618) from a remote baseband signal processing cluster together with an associated processing capacity description derived from quality of service parameters of an original radio bearer request (506) to the intra-cluster processing resource management entity (130) of the baseband signal processing cluster (100).
7. The baseband signal processing cluster (100) according to claim 1, wherein the inter-cluster processing resource management entity (140) is operable to initiate a time delay measurement (612) for determining a signal propagation delay between the baseband signal processing cluster (100) and the at least one remote baseband signal processing cluster.
8. The baseband signal processing cluster (100) according to claim 7, wherein the inter-cluster processing resource management entity (140) is operable, in response to the time delay measurement (612), to update (616) a list of suitable remote baseband signal processing clusters as possible neighbors leading to a signal propagation delay for a remote processing below a maximum allowed time delay.
9. The baseband signal processing cluster (100) according to claim 8, wherein the inter-cluster processing resource management entity (140) is operable to forward (618) a user-specific baseband signal processing request (506; 508) from the baseband signal processing cluster (100) to all remote inter-cluster processing resource management entities of the potential remote baseband signal processing clusters of the updated neighbor list.

10. The baseband signal processing cluster (100) according to claim 1, wherein the inter-cluster processing resource management entity (140) is operable to select a remote baseband signal processing cluster for remote processing related to a radio bearer request (506), which has been the first remote baseband signal processing cluster to acknowledge a related remote processing resource request (618) from the inter-cluster processing resource management entity (140) or, wherein the inter-cluster processing resource management entity (140) is operable to select a remote baseband signal processing cluster, which indicates the largest available processing capability.
11. The baseband signal processing cluster (100) according to claim 1, wherein the inter-cluster processing resource management entity (140) is operable to forward (626) a network address of a baseband signal processing unit (110) and an identifier of a user associated to at least one remote radio head of said baseband signal processing unit (110) to a selected remote baseband signal processing cluster for remote processing of radio bearer data associated to said user.
12. The baseband signal processing cluster (100) according to claim 1, wherein the inter-cluster processing resource management entity (140) is operable to forward a user-specific baseband signal processing request (628) received from a remote baseband signal processing cluster to the intra-cluster processing resource management entity (130) to initialize an allocation of at least one baseband signal processing unit (110) having sufficient available processing capabilities for performing user-specific baseband signal processing for a user associated to a remote baseband signal processing unit of the remote baseband signal processing cluster, wherein the user-specific baseband signal processing request (628) comprises a network address of said remote baseband signal processing unit and an identifier of said user.
13. A method (300) for a baseband signal processing cluster (100) associated to a first radio cell cluster of a wireless communication network, the first radio cell cluster comprising a first plurality of remote radio heads, the baseband signal processing cluster (100) comprising a plurality of baseband signal processing units (110), the method comprising:

providing information (310; 502) on an available signal processing capability of the plurality of signal processing units (110) of the baseband signal processing cluster (100); and
in response to a user-specific processing request (506) for a user associated to a remote radio head coupled to a baseband signal processing unit (110) of the baseband signal processing cluster (100):
allocating (340) signal processing resources among the plurality of baseband signal processing units (110) of the baseband signal processing cluster (100), if the information on the available signal processing capability of the baseband signal processing cluster (100) indicates sufficient available processing resources for the user-specific processing request (506), or,
sending (350) a remote processing resource request to at least one remote baseband signal processing cluster associated to a second radio cell cluster comprising a second plurality of remote radio heads, if the available signal processing capability of the baseband signal processing cluster (100) indicates not sufficient available signal processing resources for the user-specific processing request (506).