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End Node B or Node B HUB

The RBS provides the radio resources and is a component that serves one or more cells with radio coverage and isresponsible for radio transmission and reception to and from the UE.

The RBS corresponds to the domination Node B in 3GPP specifications.

The Node B is a logical node responsible for radio transmission/reception in one or more cells to/from the UE. The Node Bterminates the Iub interface towards the RNC.

 A Node B can be configured to serve as a transport network aggregation node, providing both ATM cross connect and

 AAL2 switching functions, although with lower capacity than a RANAG.

 A Node B that provides transport network aggregation services to other Node B’s is denoted “Node B HUB". 

 A collection of Node B’s which share a common ATM Virtual Path (VP) resources from a Node B HUB or RANAG node in

the direction towards RNC is referred to as a Node B cluster.

These common ATM VP resources may consist of a single Virtual Path Connection (VPC), or a set of two or more VPCs

configured for load sharing or link redundancy.

If the AAL2 connections between RNC and the Node B's in a cluster are aggregated by use of AAL2 switching, these AAL2

connections will typically be routed through a common group of AAL2 paths, established within the set of VPCs allocated to

the RBS cluster. Each such common group of AAL2 paths is controlled by an AAL2 signaling association using the ITU-T

Q.2630 protocol. Node B clusters may be formed independently by each aggregation node if more than one aggregation

node exists on the path between RNC and an RBS.

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End Node B or Node B HUB…..continued  

The node performing the transport network aggregation function for the Node B’s belonging to the same Node B cluster isserving as an Node B Cluster Controller. This function can be performed either by a Node b HUB or by a RANAG node. ARANAG node typically serves as cluster controller for several Node B clusters.

 Aggregation of VPCs from a number of Node B nodes to a common VPC, or set of VPCs, towards RNC can be performedwith or without AAL2 switching. In the latter case all ATM VCCs, including those carrying AAL2 paths and Q.2630 signalingare cross connected.

This method does not offer the bandwidth aggregation and redundancy benefits achievable with AAL2 switching. It willhowever reduce the number of VPCs that need to be configured in intermediate ATM VP cross connect nodes or networkstowards the RNC.

Node B Functions

Node B functions are divided into a number function groups listed below:

 – Radio Transport Functions

 – Supports interfaces from 1.5 Mbps up to 155 Mbps E1, E3 and STM-1.

 – Hub functionality, supporting several topologies ,e.g. rings and chains

 –  ATM/AAL2 aggregator funictionaliy can be used in low-to-medium-to-high end clusters, and allowing for a combination ofcross connect and AAL2 switching.

 –  Aggregation with AAL2 Switching gives a percentage of E1 savings.

 – Synchronization Functions

 – Bearer Functions

 – Traffic Control Functions

 – Configuration Management Functions

 – Fault Management Functions

 – Performance Management Functions

 – User Interface Functions

 – Infrastructure Functions

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Node B or Node B HUB….continued  

Node B EXTERNAL INTERFACES 

The Node B has the following external interfaces.

Iub

This is the interface between an RNC and an RBS used for traffic

related signalling. This includes both NBAP control signalling and user

data signalling using Frame Protocols.

Uu

This is the interface between an RBS and a UE. Generally, only air

interface layer 1 of the Uu is terminated in the RBS. Higher layers (i.elayer 2 and signalling), are terminated in RNC and/or core network.

Mub

Mub is the management interface provided by the RBS. It is used for

element management and network management.

GUI

The GUI, Graphical User Interface is provided to the operator to

enable operation and maintenance of the RBS in a user friendly way.

VMI

The Visual and Mechanical Interface is the interface a human site

visitor encounters. It consists of visual indicators (e.g. LEDs),

manually operable switches/buttons (e.g. board reset button) and

incoming external power. Also, connectors and the actual mounting of

cables and screws etc. is part of this interface.